Project on New Product Development

SEQUENCE OF PRODUCT DEVELOPMENT TO IT’S PROMOTION AND SALE :

The assurance of customer quality satisfaction must being during new product development. Whenever a new product is planned and a new design begun, fully as much as major new marketplace opportunity, there will be potential quality risk to the company. Because this is so, there must be a thoroughly structured series of activities to minimize this risk and to assure the quality of the new design to satisfy the customer in the marketplace.

A. CYCLE FOR DEVELOPMENT OF NEW PRODUCT :

The cycle for development a new product that takes place in many companies is now summarized. Several steps may be consolidated in some companies; the order of steps may be interchanged in others. Of steps of steps may be interchanged in others.

1.A new market opportunity to serve customers is identified and a new design is contemplated.

2.Technical, production, customer-use, and marketing analyses are made of the marketplace and the design. Cost targets, production volume, and price levels are preliminarily established.

3.General specifications are written. They may be in the form of 

a.Sales propositions in the case of job-lot production.

b.Rough functional specifications for products that will be manufactured in mass quantity.

c. Broad identification of the coverage of the quality program for the product.

d.Overall outline of product service and maintenance objectives, quality-performance requirements, product life cycle targets, and other related product goals.

4.Preliminary design is made.

5.First prototypes are made. An extensive program of testing the characteristics of this design is carried out, including the components and sub assembling to be used. For products with electronic computing modules, the software will be evaluated and testing begun.

6.Preliminary design review takes place. Preliminary classification of characteristics of the design proceeds (including components and sub assembling); test procedures are evaluated; manufacturing and assembly capability are assessed; cost targets are reviewed; quality levels are identified design changes are defined and reviewed; process and manufacturing considerations are identified.

7.Intermediate design is made, including production drawing, and prototypes are build.

8.Tests are made on this inertmediate design review takes place. Action continues on classification of characteristics and upon manufacturing, assembling, and test requirement. Marketing and pricing estimates are reviewed. Design changes are defined and reviewed.

9.Final design is completed along with final specifications, standards, guarantees, quality planning and production drawings. Life and performance tests are culminated before final design completion. Components, section plants are developed; tool design and procurement are completed; and costing is finalized.

10.Sample production units are built.

11.Shipping and service procedures are defined.

12.Capability studies are made of new and current machines equipment and processes.

13.Supervisors and production employees are trained. Pilot runs are made using sample composed of production units. The results of the tests of these samples are incorporated into the design and manufacturing specifications if and as required.

14.Final design is reviewed. Product, software when appropriate, equipment, process, facilities, and development test results are analyzed by those functions which need to become familiar with the plans and which can make constructive inputs. The basic product cost targets and lie cycle cost objectives are reviewed to assure the goal of “design of cost”. Product qualification tests are satisfactory completed. Release for manufacturing of production tools and facilities is given, consistent with final design review approval and completion.

15.Marketing announcements are confirmed; product information manual, service publication, and training aids are competed, all with thorough attention to quality considerations.

16.The unit is released for active production.

B. The Fundamental Activities.

The fundamental activities of new-design control routines within the total quality program mesh into this sequence. These activities are now summarized:

1.Establishment of the quality requirement for the product. This involves analyses that culminate in customer-satisfaction-oriented specifications and standards which incorporated performance, reliability, maintainability, and safety requirements and the cost quality balance for the product and the components. It includes activation of that portion of the quality program which covers the reproduction evaluation and testing of the product

2.Design of a product which meets these requirements. This involves the establishment of the detailed drawing for the product and the preparation of the related engineering instructions. It includes following the quality program for classifying product and process characteristics, for conducting product life and safety evaluations, and the carrying on of environmental and other tests to determine the reliability of components and components and subassembling and of software where necessary. It also includes field tests and performance studies of assembled prototype of handmade samples. Simulation studies of product quality may be made where physical prototypes cannot be made available. Product cost and life cycle quality and cost goals are evaluated.

3.Planning to assure maintenance of the required quality. This involves the formal activation of the details of that portion of the quality program which covers the control of purchased material, the maintenance of quality during processing and production, and the assurance of quality during field installation and product servicing. It also includes the development of the final specifications for the quality information equipment which are required for incoming material, in processing control and field testing and evaluation.

4.Prepoduction review of the new design and its manufacturing facilities; formal release for active production. This involves the planned, formal evaluation of the designed product at several stages of the complete design process to assure its capabilities of meeting its warranties and guarantees under conditions of actual use. A series of performance and product qualification tests will be conducted, in terms required by the quality program, to review the product in all important customer and end-use aspects.

Particular emphasis is placed upon components testing under conditions which simulate actual customer use.

These four elements are quite in new design control programs of plants which produce such a wide variety of products as major electronic and mechanical products.

C. Typical New Design Development Sequence:

1.When such a new-design initiation is identified, representatives of key functional groups of the company work together to begin examination and evaluation of design data to ensure that the new product concept will meet the intended quality requirement. 

One step in this evaluation is the initial formal design review meeting on the product, for consideration of its concept, function, and preliminary design. The product design engineer chairs this meeting, with close participation by quality engineering. Also in attendance are representatives from marketing, production, manufacturing engineering, purchasing and production control, product service, and other key areas as indicated.

2.The purpose of this review are to discover critical features of the proposed design for expected customer use; to anticipate trouble the factory may have producting the product or in product service in maintaining it.

3.The engineers plane and carry out the necessary analyses and test programs aimed at finding answer to design-oriented questions generated in step 2, with close participation and support by quality engineering and  marketing, manufacturing, and service-oriented investigations that also from step 2.

4.The finding from the analyses and tests are incorporated by the design engineering into the new model design, as appropriate, classification of difficulties are eliminated. These changes are incorporate into the drawings and specifications. Life and performance test are begun and quality engineering product evaluation takes place. 

5.While these test are in progress manufacturing engineers complete the planning for all the processing equpements and tooling. Work proceed by marketing and production control to detail spare-parts requirements, purchasing with close participation by quality engineering.

6.Intermediate design review takes place.

7.When the production tools and processing equipment’s are received manufacturing begins and a pilot assembly run is started.

8.The engineering manufacturing & quality control analyze the performance of the pilot run. They also study the quality of parts  and assemblies produce for pilot run and final design review procedure is initiated.

9.Result of these analysis  are incorporated by the designer in to the final design specification, standards, and guaranties.

10.Final product qualification tests take place. All product documentation, configuration control, product service, advertising, and sales brochures are competed. Final design review is completed.

11.The product is approved for mass production and sale.

INVOLVEMENT OF CENTRAL QUALITY ASSURANCE DEPARTMENT IN PRODUCT EVALUATION AND RELEASE:

Objective

This chapter deals with the procedure of the quality system for evaluation and release of new models.

Personal response

The set(s) are received from PDD/Project Cell/ME, corresponding to the stage of evaluation as defined section.

Product identification

The set received for evaluation is identified as per the exhibit “Set Identification” which indicates details such as model number, stage of evaluation, in and out date, responsible person and other relevant details. 

Product evaluation stages

Major stages during Product-Evaluation Process w.r.t new models, are as follows.

1.Development model approval

2.Design approval(TTR1)

3.Pilot production approval(TTR2)

1.Development model approval

Receipt of sets: 

At this stage one or two number of sets are submitted by product design and development department (PDD). PDD also submit relevant documents such as a product specification, engineering specification, circuit diagrams etc. along with set.

Test schedule:

The test schedule of applicable tests is defined as per quality plan At this stage, emphasis given on verification of implementation of action taken against earlier field-complaints for some chassis, apart from electrical design aspects.

Reports of non-conformity:

Non-conformity if any is reported as per exhibit “observation/non-conformity report”.

Corrective action are informed and implemented by PDD department, against non-conformities noted.

Product release:

Release is accorded, for TTR-1 after confirmation of effectiveness of action taken against NCs and after review of plan/comment for closure of open non-conformities(if any).

2.Design  approval (TTR-1)

Receipt of sets:

At this stage 5 nos. of sets are submitted by project cell department.

Test schedule:

The test schedule of application tests is defined as per quality plan: At this stage, the set is checked for additional parameters like, aesthetics(color-scheme), packing, drop test etc.

Report of non-conformity:

Non-conformity if any is reported as per exhibit “observation/non-conformity report”. Corrective action are and implemented by ME department, against non-conformities noted.

Product release.

Release is accorded, for pilot-production (TTR-2) after confirmation of effectiveness of action taken against NSc and after review of plane/comments for closure of open non-conformities(if any).

3.Pilot Production Approval(TTR-2)

Receipt of sets:

At this stage 10 nos. os sets are submitted by ME (Manufacturing Engineering) department.

Test schedule:

The test schedule of application tests is defined as per quality plans. 

Test method and acceptance criteria:

The test schedule of application tests is defined as per quality plans: at this stage, emphasis is given on critical parametric measurements likely to vary due to process; and also to the confirmation of UGB and the carton box w.r.t product specifications.

Reports of non-conformity:

Non-conformity if any is reported as per non-confirmatory reports. Corrective action are informed and implemented by ME against NCs.

Product release:

Release is accorded, for mass-production after confirmation of effectiveness of action taken against NCs and after review of plane/comments for closure of open non-conformities(if any).

Retention of reference set(s)

One no. of set released after every development stage, is kept COA for reference till the next stage. One no. of set released for mass-production is retained as reference, for period of three months from start of mass-production.

Database updation:

Database having details such as model no., chassis no., brand, sub-brand, special features, type no. of major components etc. is updated after release of any new model.

Pre-sale inspection:

Pre-sale inspection is jointly conducted by factory, sevice and marketing at godown prior too release in the market.

FEED BACK OF INFORMATION FROM THE FIELD.

The field organization has an important responsibility in feeding back information to the company such flow provide a further information technique for obtaining action in improving product quality and is a most useful measurement of quality properties.

Any design feature that cause difficulty in servicing need to be made known, needed.

1.ACTUAL PRODUCT PERFORMANCE DATA are necessary along with supplementary data concerning condition under which the performance data were taken.

Field failure data customer complaints should be sufficiently detailed to provide a means for analyzing the causes, so that proper corrective action can be applied.

2. Report format can be designed to make it easy for repair personal to note the cause of the malfunction of a product.

3.More sources for such data are service tickets, service call reports installation report. Returned apparatus report and other complaints when systematic collection of such  data is included in quality cost accounting system of the company, the organizational component found responsible for causing the customer complaints can be charged for repair or replacement cost.

Personnel from central quality assurance (CQA) product design and development (P.D.D.) manufacturing engineering (M.E.) qualities assurance (Q.A) and central service operation (C.S.O.) 

ACTION REPORTS ON FIELD FEEDBACK PROCEDURE FOR DATA ANALYSIS AND ACTION W.R.T.  F.C.R.. DATA:

Complaint lodged by any customer or dealer is attended by the respective service center of that particular area. The data such as model no, serial no. warranty period, nature of complaint and action taken etc. is sent periodically by the respective zonal service centers to ‘ CENTRAL SERVICE OPERATION’ and sales department sends data about.

In –warranty population to C.S.O. based on the field complaints and In-warranty population, C.S.O. calculates F.C.R. for each model as per following formula.

Field calls rate (%)=( no. of complaints / in warrenty population) * 100

The F.C.R. report with all relevant details is sent by C.S.O. to factory (C.O.A.) on monthly bais.

REVIEW OF F.C.R. REPORT

1.the monthwise national F.C.R. report received from C.S.O. is reviewed and the “F.C.R. TREND” graphs is updated and communicated to management.

2.data collected from C.S.O. is analysed so as to find out the major contribution to field complaints for each chassis.

Major contribution to field call rate report which indicates total no. of field calls, in warrenty population ,F.C.R. data, 

Top-5 major contribnution along with their contribution for all the chassis is prepared and communicated to all the concerned department  in the organization.

The details w.r.t. the major contributors are reviewed for possible causes and are attributed as design, process and component.

Action On Major- Contributors

Following measures are considered depending on the type and severity of the problem.

1.Review of the defective components..

2.Review of the similar complaints in the factory.

3.Information about chassis details and field conditions.

4.Visit to customer dealer etc.

Based on above analysis given by the concerned department like design, component and process corrective actions are planned and effectiveness is verified.

Periodical meeting is held among the representatives of factory and those of C.S.O. information about action taken and planned is communicated in this meeting to C.S.O. the details of implementation of the corrective action in the sets from production line is informed to C.S.O. through “action taken report”.

If the solution is to be applied only against particular complaints and not as design change, then it is informed as service solution to C.S.O>

C.S.O> communication this information to all service centers.

Fast feed back:

Fast feed back depending upon the repetitiveness or severity of critical fields complaints for which immediate attention by the factory is necessary C.S.O. informs the feedback about such complaints generally reviewed as “ FAST FEEDBACK”. 

Customer attitude:

Customer attitude determination is intended to obtain and measure the opinions impression, reactions and degrees of satisfaction of individual customer regarding the overall efforts of the company towards providing quality for its products/ or service.

The result of such program are a basis for determining which factors customer regards as most important in a product for establishing corrective action on reported problems and for achieving  improvement in customer attitude.

Among the important attitudes which can be measured are the following.

1.Qualities of shipment.

2.Qualities of product installation.

3.Qualities of product operation.

4.Qualities of product functional design.

5.Maintainability.

6.Serviceability ( easily followed instructions easily obtainable tooling and so on.)

7.Qualities of service.

There are many methods and medias to collect this information one of the most generally used as questionnaires sent directly to the customer now a days it conducted through internet or telephone interviewing or personal visit by a company representatives.

Useful information can also be gained by examination of buying trends (graph) comparison with  bench mark. Model to model comparison and so forth.

Although the favorable attitudes and good will of each single customer is important to a company, it is apparent that some accounts are more critical than others regarding volume, size, revenue, cash , profit, potential business, prestige, image, and so fourth for this reason “ customer rating plan” is sometimes adopted as a means weighting customer response between  “critical customer” and  major customer.

CONCLUSION:

From this study I conclude that for compete with leading benchmark in the market and for customer satisfaction. Company should have to concentrate on the customer satisfaction, and company should study the customer attitude, and design should such as to improve:

1.Qualities of shipment.

2.Qualities of product installation

3.Qualities of product functional design.

4.Maintainability.

5.Serviceability.

6.Qualities of service.

Project on Weight Reduction

INTRODUCTION

In recent years it has become important for automobiles to satisfy many conflicting demands, as the demand for the automobiles increased, the engineers then stepped up their efforts to cut costs and look for processing methods that require fewer operations, less time and less materials. Due to this competition among automakers, engineers started making automobiles, which would increase power and performance, lower fuel consumption; lower polluted emission, decreased vibration and noise.So the need arose for the reduction in weight of the entire automobiles structure. Newer materials and alloys were used to reduce the weight. Also material substitution started taking place thus the concept of rationalizing the entire auto structure began with the addition of never materials to reduce weight came many more advantages.

Here in this seminar, I have tried to present how effectively the weight of an automobile can be reduced with increase in its efficiency, performance, etc.

NEED FOR WEIGHT REDUCTION

More weight implied more fuel consumption. This reduces the efficiency of the engine. Fuel economy is a thing of primary concern. Fuel (petrol/diesel) being a non-renewable source of energy, it is fast getting depleted or exhausted. Nevertheless its demand is increasing, ultimately its prices are touching the sky. Hence weight reduction becomes necessary to increase fuel efficiency and better the engine performance and reducing the costs also.bulkier the automobile, the less elegant it is in its 

Movement drive. Weight reduction enhances its performance i.e. mobility. The vehicle has a greater pick-up smooth drive, more speed less vibrations and less noise.In order to improve the fuel consumption of a vehicle, it is of general idea to improve consumption of a vehicle, it is of general idea to improve combustion efficiency to minimize aerodynamic drag and rolling resistance. Here reducing vehicle weight is much effective in minimizing the rolling resistance. Also it is becoming necessary to control exhaust gases fuel to increased public concern in these years.Thus considering all these advantages weight reduction is the in-thing in the automakers mind.

TYPES OF WEIGHT REDUCTION METHODS

From the automobile manufactures perspective, there are four basic approaches to weight reduction.

1.Material substitution.

2.Load reduction at the source.

3.Load averaging.

4.Load control.

With regard to materials substitution the objective involves replacing an existing material or component with one that its lighter overall but still capable of delivering the desired performance. Thus weight reduction can the achieved by using high strength lightweight alloys materials having high heat resistance and materials that provide highly effective sound insulation.

Load reduction can be achieved by reducing not only load but vibratory forces and heat emission as well. According to these principles, sound reduction at the source can reduce the amount or sound insulating material required or as another example the use of heat insulating glass could enable a reduction in the size of air conditioning units.

Weight reduction by load averaging results from optimizing structures and shapes and reducing excess materials. Load control or the high precision evaluation of load fluctuation enables weight reduction by using materials and structures at their performance limits.

WEIGHT REDUCTION METHOD

Various weight reduction technologies have been developed. Based upon the basic approaches to weight reduction outlined above. As depicted in the following fig., these technologies can be broadly categorized as design, materials and processes, each of which has close inseparable linkages with the others. The idea of reducing weight by rationalizing the arrangements of important parts in the car began the letter half of 1970 and is now widely improved. An example of this is the conversion of wheels from rear wheel drive to front wheel drive. At present approximately 70% of Japanese passenger cars use front wheel drive. The front wheel drive enable an approximately  4% weight reduction in the vehicle as well as space improvements. The concept of rationalizing the overall auto structure can be extended to individual parts as well by applying such techniques as integration, reduction, downsizing thinning and hollow structure design. For an example, the change of the Nissan Primera’s fuel tank steel to plastic enabled a weight reduction of approximately 30 % It is also possible to apply rationalization to fabrication.  

An example is a leaf spring for the front suspension of some models of the Nissan Vanette. Prior to 1985 the spring was made of multiple steel leaves. With the development of an industrial filament winding method, however if became possible to use a single piece glass fibre reinforced plastic which was then capable of accommodating tailored designs. The new leaf spring contributed to an approximately 70% weight reducing as well as improved ride for the vehicle. Another example of material substitution is the plastic outer body panel employed by the Nissan Be - 1. In addition to enabling a surface profile that is possible only with plastics an approximately 25 % reduction in weight was achieved. By substituting aluminum in the outer body panel and other part of three Nissan modes weight reduction of as much as 45 % were achieved which is far greater than reduction achieved with plastics.

THE STATUS OF WEIGHT REDUCTION

Prior to the turn of the century, the first automobiles were made primarily of wood and canvas. Soon however the changes were made to steel sheet and high-tension steel sheet has long since been applied. With the recent push towards weight reduction however steel has consequently become the subject of intense scrutiny. Even though steel sheet are now being used in variable thickness it no longer has exclusivity in a number of application, for example panels made of aluminum alloys and plastics are being used although the quantity is very small. In general the major advances in steel related weight reduction technologies might have already been made. Indeed it is possible to conclude that with regard to weight reduction most of the rationalization opportunities have been exploited as such the major area of innovation is materials substitution.

ROLE OF ALUMINIUM IN WEIGHT REDUCTION

Automotive applications of aluminum sheet are on the rise and are expected to accelerate throughout the decade. The metal’s low-density revocability fabricability gives it an edge over steel, plastics or copper depending on application. Demand fro aluminum automotive body sheet is projected to 

increases to 45000 tones annually by 1997 up from its current level of 10000 tones. Aluminum’s position with   respect to steel has been enhanced in recent years by the development of stronger alloys and also aluminum unlike plastics can be handles and formed using the existing plant infrastructure originally installed to process steel sheet. The aluminum heat exchanger market is larger and better established than body sheet aluminum continues to displace copper in radiators evaporators condensers and better heater cored and its share of these applications now exceeds 60 %.

Also wrought cast and forged aluminum sheets are used for wheels, which now account for 38 % of the market. Thus it has been said that aluminum is the material with the highest potential to impact automobile weight.

ROLE OF PLASTICS IN AUTOMOBILE

Plastics are now days extensively used as a major lot in the purpose of weight reduction. Plastics are contributing a lot in the purpose of weight reduction. New types of plastics are being developed which have excellent propertied useful in automobile industry. Fields in the use of plastics such as plastic gears piston rings casings of different parts, thermoplastics olefins, manifolds are now being shaped by plastics. There are also less costly and satisfy all the requirement such as temperature condition, smoother surfaces oil and grease resistance and can also be moulded to any shape.

Plastics are also used for the under hood application such as air filter housings radiator and tanks and cooling tanks. Some examples of plastics used in under-hood applications are Glass-Reinforced Nylon 6/6 and Hifax Series Thermoplastics.

THE CHANGING UNDERHOOD ENVIRONMENT

Higher corporate average fuel economy (CARE) requirement favor the substitution of lightweight component for traditional metal parts. Tougher emission standard foster the development of cleaner burning fuels, which can attack metals and other materials used to handle conventional gasoline. The corrosive potential of other automotive fluids-coolant, grease motor oil and brake fluid also must be considered in materials selection decisions.

Another important factor is a materials heat resistance. Underhood temperatures continue to rise at designers pack more hardware into as engine compartment that is shrinking due to styling trend such as sharply made hoods. In addition earlier weight reduction programme contributes to increased levels of noise vibration and harshness. Quarter running vehicles will rely at least in part on UTH components made of materials that demand engine noise and vibration.

SMC: -

Growth in the use glass fibre reinforced sheet moulding 

compound (SMC) and bulk moulding compound (BMC) materials based on vinyl ester resins is expected.

A glass fibre constant of 20 to 30 wt. Imparts adequate strength 

for a component such as valve corner.

SMC is a proven material for exterior body parts and is now 

being considered for value corners, oil pans and similar UTH component. Detroit Diesel and Cummins Engine are replacing car aluminum covers with SMC covers. Reported advantages of the switch include reduced valve train and other engine noise, elimination of machining via parts consolidation and improved seal integrity due to better dimensional stability weight and cost saving of 30 % and lower stricture borne noise levels are predicted by substitution SMC vinyl ester for aluminum in the oil pan for the engine German automakers also hope for a boost in engine performance i.e. oil should heat up faster because of the plastic’s lower thermal conductivity.

ROLE OF CERAMICS IN WEIGHT REDUCTION

Ceramic materials offer new and unique solution to engine design issues. They offer advantages of lower density, excellent wear resistance increased stiffness low thermal expansion and more high temperature capability over the traditionally used metals. The use of ceramic requires consideration of reliability defining specification for good wear resistance and controlling and reducing cost through optimization of the materials for the application.

LIGHT WEIGHT BENEFITS OF CERAMIC

Ceramic of high strength silicon nitride composition offer densities one half to one third that of the austenitic stainless and nickel alloys which are only suitable for moderate temperature application. This combination of low density with good high strength make ceramic ideal materials for light weight valves and valve train component, piston pins and piston crowns. The weight ceramic valve offers a good example of the benefits of weight reduction and the need for a systems approach. The valve weight for an example spark ignited engine can be reduced as shown in table.

Analysis indicates that the resultant weight decrease would allow the valve spiting opening load to be reduced from 500 N to 260 N while maintaining suitable valve gear  dynamics. For the system analyzed the opening spring load reduction would produce a resultant improvement in vehicle fuel economy of 0.8%. Not considered are the additional potential benefits of higher 

engine operating speed, more rapid valve opening and closing with their resultant higher power. Engine allowable speed could be increased because of the lighter weight if no change in the spring occurred. Camshaft stresses at the original engine speed will be reduced  approximate 20 % if the 260 N spring open load is viable. Also as the ceramic materials have low co-efficient of thermal 

expansion they can be used in engine construction.

USE OF METALS AND METAL ALLOYS IN WEIGHT REDUCTION

Automakers continue to effectively use metals to reduce the weight and improve the performance of auto engine. Although plastic are finding more applications in automobiles engines automakers rely on the use of metal products for several engine component such as engine blocks piston connecting rod and valve trains. This extensive use of metals provides opportunities for weight reduction and automakers who are seeking cost effective applications of light metals, metal-matrix composites and microalloyed steels in mass-produced engines.

IMPROVING POWER TO WEIGHT RATIOS

Proven methods to reduce weight in mass-produced autos include the use of aluminium and magnesium alloys as replacement for steel and cast iron. Magnesium castings are attractive candidates for engine applications because they are lightweight and have good strength and stiffness at both room and elevated temperatures. However they are not yet widely used by U. S. automakers in mass-produced engines. The average magnesium content of a U.S. built vehicle is about 1 Kg., with only a fraction of that being used in the engine.

Current engine applications include valve covers, cylinder head covers, intake manifolds, rocker arm covers, air intake adapters, induction systems and accessory drive brackets. In addition to magnesium’s low density, these applications may take advantage of the material’s high damping capacity and the thin wall capability of the magnesium die-casting process.

Aluminium alloys, on the other hand are widely used in high production engines because of their low density, corrosion resistance and good forming & casting characteristics.

A large weight reduction can be achieved by replacing cast iron 

engine blocks with either aluminium blocks having cast iron liners or liner less hypereutectic silicon-aluminium engine blocks.

Further weight reduction of engine blocks is possible by using reinforced aluminium metal matrix composite (MMC) liners. For Example, Honda Engg. Company Ltd., Japan has developed an aluminium block that incorporates cylinder liners made of alumina/ graphite short fibre reinforced aluminium. The block provides higher performance, is smaller and weighs less than either cast iron blocks or aluminium blocks with iron liners. The liner starts as a thin walled (2 mm., 0.08 in.) fibre perform, which undergoes a die casting process that allows aluminium to penetrate the fibre without causing damage to the perform.

The MMC liners are machinable, although the hardness of the 

alumina fibre requires the use of tooling having sufficient wear resistance, such as polycrystalline diamond cutting tool.

Other successful applications of aluminium MMC in automobile 

include drive shafts and pistons. In drive shafts, weight reduction is the primary benefit. A one-piece composite shaft, such as the graphite fibre, reinforced aluminium MMC also eliminates the need for a centre bearing.

ALTERNATE MATERIALS FOR WEIGHT REDUCTION

Material substitution is an effective approach for automotive 

engineers trying to reduce part weight. Consolidate parts, enhance efficiency and cut costs. Conventional materials have been replaced with aluminium matrix composites, thermoplastic composites, recycled resin, titanium and ductile iron.

ALUMINIUM COMPOSITES REPLACES CAST IRON

Engineers at Toyota replaced the cast iron hib of a crankshaft damper pulley with an aluminium matrix composite to reduce weight and engine vibrations. The pulley drives the alternator and power steering pump and acts to reduce torsional and bending vibrations of the crankshaft significantly.

One of the hub’s essential function is to maintain tension at the boss through which the hub is bolted to the crankshaft. Conventional aluminium alloys  deform plastically at the boss when the temperature rises because of thermal expansion difference between bolt and boss. They also deform because of creep after the bolt is tightened. However, when aluminium is reinforced with short aluminium fibres, it resists deformation and expands less when heated. To fabricate a composite hub and crankshaft pulley, fibre preforms were made by vacuum forming, then infiltrated with molten AL – S – MG alloy. Here weight was reduced by about 40% and crankshaft pulley weight was reduced by about 20%. These reductions allow the engine to rotate faster, enhancing engine performance.

ALUMINIUM COMPOSITE LINES CYLINDERS

Engine cylinder blocks cast entirely of iron were common until 

aluminium die cast blocks were introduced in the late 1970’s. However, the cylinders were typically linked with cast iron because aluminium has poor abrasion resistance and warps at cylinder temperatures. Although the aluminium block significantly reduces engine weight, the high-density iron liners hindered further improvements. To overcome aluminium lacks of wear and heat resistance in this application, Honda engineers developed an aluminium blocks with an integrally cost aluminium matrix  composite liner. The MMC layer consist of 12% alumina fibre and 95graphite fibre in an aluminium matrix and ranges from 1.5 to 2.5 mm. Thick depending on location.

Test shows composite wear depth is only one third that of the monolithic aluminium silicon alloy and is approximately equal to that of cast iron. Both scratch and seizure limits of the cylinder liners vs. the piston rings move upward as alumina fibre volume rises and they are pushed even higher when graphite fibre are added to alumina. However, total fibre volume has been set at 21% to facilitate finishing of the inner cylinder surface.

In addition to wear improvements, cooling efficiency is also improved. The temperature measured between the cylinder bores of a four cylinder engine operating under maximum load is approximate 10% lower than of cast iron liners. As a result of improved abrasion resistance and cooling 

performance, the block can be made smaller and engine can run faster. Overall weight is reduced by 50% compared with a cast iron block and by 20% compared with aluminium block having cast iron liners.

REPLACEMENT FOR BUMPER FASCIA

Conventional elastometer modified polypropelene (EMPP) has been a successful bumper fascia material because of its low co-efficient of thermal expansion (CIE), high impact resistance or toughness and paintability. However, attempts to cut the weight of large EMPP fascia by reducing material thickness have been accompanied by an unacceptable decrease in touchness. To overcome this problem, engineers at Toyota took a non-traditional approach to design EMPP materials and came up with “Super Olefin Polymer”. This new material has the thermal expansion characteristics, low  temp., impact resistance and portability of EMPP plus increased stiffness, which is required, for thin section parts, a higher melt flow rate or fluidity, which ensures high productivity in molding and high surface quality (rivaling that of sheet) in thin section and enhanced hardness, which makes fascia more resistant to scratching. Other reported advantages over conventional EMPP include a 11% total cost reduction and the ability to withstand 120 C paint baking cycles without deforming. In addition, the weight of a typical fascia is reduced by about 15% when super olefin polymer is substituted for conventional EMPP.

Recycling of the new material is said to be easy because all resin components are thermoplastic. And repeated recycling has no negative effect on low temperature impact resistance, stiffness, paintability or other properties and performance characteristics.

ALUMINIUM COMPOSITE BRAKE ROTORS 

Brake rotors made of aluminium matrix composites combine the low density of aluminium and wear resistance of ceramics. They weigh only about half as much as cast iron system, conduct heat three times more efficiently, and also reduce noise and vibration. The matrix alloy closely approximates the Al-Si casting alloy 359.0. the addition of 20% SiC particles greatly enhances wear resistance, increases thermal conductivity, raised room temperature strength & stiffness and improves high temperature strength in addition to its properties of weight reduction.

TITANIUM CONNECTING RODS BOOST POWER

An automobile engine’s connecting rods convert the reciprocating motion generated by combustion of the air/fuel mixture into high-speed rotary motion. Connecting rods must withstand high stresses and the surfaces that mate with pistons and crankshaft must resist wear at high surface pressures. For these reasons, connecting rods require usually high levels of strength, stiffness and wear resistance.

Connecting rods for production engines are generally made of medium carbon steel. Potential weight saving material for these parts include higher strength carbon steel and lower density materials such as titanium. Titanium alloys are particularly good candidate because they provide higher specific tensile and fatigue strengths than competing materials. Unfortunately, the alloys compare very unfavorably with other metals in terms of wear resistance (abrasion, seizing and scuffing, formability and machinability).

ADVANTAGES OF USING TITANIUM AS CONNECTING RODS 

Test data confirms that the new connecting rods offer better fatigue characteristics and an ample margin of strength when compared with parts made of medium carbon micro alloyed steel. The titanium parts weigh approximately 30% less than steel; connecting rods which translates into a weight saving of 1.2 kg. Lighter connecting rods reduce engine inertial force, which helps increase the seizure limit by thickening the oil film between crankshaft and connecting rod. The result, an increase provides a significant increase in output power. Use of the titanium parts also lowers engine vibrations and noise levels.

]

ENGINE WEIGHT REDUCTION

It was found that by application of lightweight materials, the engine performance of weight-reduced engine could be improved. That is improvements in response and friction loss. In particular, weight reduction of the major moving components such as connecting rods not only contributes to reduce friction loss but leads to a weight reduction for other components.

Applying weight reduction measures to an engine is not so effective in improving fuel consumption of a vehicle because engine weight accounts for no more than 10-15% of the vehicle one. However, since reduced engine weight induces to decreased external loads to chassis components, such as engine mounting systems and base carrier components including suspension, and engine should be so designed as to reduce these weights as a whole. Therefore, reducing engine weights brings about a reduction in overall vehicle weight, which results in fuel consumption for the vehicle. As means for reducing weight, there are several methods available including substituting lightweight materials for conventional materials, that is to decrease specific gravities, rationalization of structure(decrease number of the parts through integration) and dominizing (decrease the volume of each part).

The engine weight could be reduced by 37 kg. From a base one of 162 kg. (excluding engine oil and coolant). This corresponds to 23% weight reduction. As shown in fig. 13, the components weight ratio of the materials are 53% steel for the weight reduced engine (86% in the base engine), 33%(13%), aluminium alloys 7% (1%) plastics and elastomers , 6% (0%) other light weight materials such as titanium alloys and magnesium alloy, and 1% (0%) ceramics.

CONCLUSION

With the help of this seminar, I hope, I have been able to show how much important it is to reduce the weights in an automobile. As newer technologies are coming up, newer metals or alloys are being invented which are light in weight. Also the reduction in weight also reduces the cost to some extent in most of the cases. Also aluminium, plastics, ceramics, MMC’s are being used in automobiles in large quantities than ever before. Now a day more and more cars can be seen on the road. I would like to end my seminar saying that this aspect of automobiles is very important for the future years.

Project on Vortex Tube Refrigeration

INTRODUCTION

 “A vortex tube is a device, which produces cooling at one end and heating at other end simultaneously without having any moving part if high pressure air is available.” 

George Ranque in France in 1981, observed low temperatures in the rotating flow of air in cyclone separators.  Based on this observation, he deviced an arrangement known as the Ranque tube or Vortex tube.  In 1945, a German Engineer Prof. Hirsch further developed this. It was announced that a device is developed using compressed air discharged hot and cold stream simultaneously at its two ends.  Hartnett and Eckert gave a theoretical explanation of this behaviour.  The performance of the tube depends upon: 

a)Air Parameters b)Tube Parameters 

Timothy of I.I.T. Bombay obtained a drop of 780 C with inlet air at 8 bar and 300 K.  Hinge and Naganagoudar of I.I.T. Bombay were able to increase a drop to 830 C.  Parulekar developed a “short vortex tube”.  Its performance is not dependent on inaccurate workmanship or by a poor surface finish.

WORKING OF VORTEX TUBE 

 Fig.1.Counter flow vortex tube.

Fig.2. Uniflow vortex tube.

Fig.1. Shows a simple vortex tube.  In this tube, the outside air, duly compressed and cooled in the heat exchanger expands through a nozzle.  The nozzle, which is fitted tangentially to the pipe that is shown in fig. 

The tube can be made either counter flow or uniflow.  The counter flow is shown in Fig.1. A nozzle arranged tangentially at one end of a tube is supplied with compressed air.  The tube at that end is partially closed by diaphragm with a central hole approximately half the tube diameter. 

At the other end of the tube, a valve restrict the exist of air.  A stream of cold air leaves through the orifice when the valve is partly open.   While, the stream of warm air leaves through the valve.  On setting of the valve, the temperature of the cold air stream and the flow rate can be changed.  When the valve is fully open or close, the following are the results. 

(a) Valve fully open. All air comes out through the orifice.  There is no reduction of temperature. 

(b) When the valve is closed, the flow rate of cold stream increases.  When the flow rate is ½ or 1/3 rd of total, the temperature of cold air falls to a minimum value. 

(c) The temperature of the cold stream will increase again if the valve is closed further.  

Fig.2. Shows the uniform design of a vortex tube.  In this design, the cold stream comes out at the same end as the warm stream.  The central core of air stream is separated by a special arrangement of orifice and valve.  This design is not efficient as counter flow arrangement of a vortex tube. 

THEORY OF VORTEX TUBE

The theoretical explanation given by different research workers differs.  All research workers have tried to explain how in absence of a mechanical device, a flow of the core of cold air and the hot air around the periphery takes place.  The swirl motion is created when the compressed air expands through the nozzle.  By injecting smoke, this has been tested experimentally.  One of the theory generally accepted is as under: 

(i)The compressed air on expanding through the nozzle forms a free vortex due to the particular shape of the nozzle. 

(ii)The expanded air then moves a towards the valve end. 

(iii)The vortex travels along the periphery of the tube till it reaches the throttle valve due to centrifugal force. 

(iv)As the vortex of air reaches near the valve, the K.E.  of the air is converted into the pressure energy.  This will give point of stagnation. 

(v)The stagnation pressure near the valve (up stream region), which is partly closed, is more than the atmospheric pressure, a reverse axial flow starts from the valve end. 

(vi)This reversed flow comes in contact with forward moving free vortex.  This contact causes the reversed flow to rotate with it. 

(vii)There is an energy transfer from the central core to the peripheral layer.  Because of this energy transfer, central core is cooled and the outer core will be heated up. 

(viii)The outer layer is also heated up because of the friction with the tube and fluid friction. This energy (or heat) is given to the central layer.  The energy supply is insignificant compared to pumping of energy from core to the outer layer due to turbulent mixing in the centrifugal flow fields. 

(ix)This will result in a flow of cold core surrounding by a hot concentric flow field in the vortex tube. 

(x)The centre core passes out through the diaphragm emerges as a cold stream. 

(xi)The outer layer passes out through the throttle valve as hot stream. 

If the valve is fully open all the air go out at an average temperature slightly lower than the inlet temperature.  The diameter of the diaphragm is smaller than the chamber 

diameter.  The natural tendency of air is to flow towards the hot end, the end having larger diameter.  The reverse flow is not possible and hence no cooling will be obtained. 

The extract phenomenon of energy transfer is still need detail investigation. The length of hot tube is very important for proper performance of a vortex tube.  The heat transfer from the outer to inner layer of air is more if the length of the tube is long.  The temperature of core air will increase.  The central core is unable to transfer its kinetic energy to the outer layer in sufficient quantity if the length of the tube is less.  Thus the kinetic energy is not decreasing sufficiently.  This will affect the stagnation temperature and it will also not reduce sufficiently.  The usual variation in the length in design is from 20 to 40 times the tube diameter.

COMPONENTS 

Fig.3.Componant of vortex tube.

1. Nozzle: -

The nozzles are of concertinaing type, diverging type or converging – diverging type as per design.  An efficient nozzle is designed to have higher velocity, greater mass flow and minimum inlet losses. 

 The nozzle is used to develop a high tangential velocity in the chamber.  Hence, it has to be tangential to the chamber and the losses in the nozzle should be reduced to minimum.  The inlet area should be sufficiently large.  The length of the passage should be as small as possible.  The surface area should be minimum.  The nozzle should not be delicate. 

 Bombay in 1966, studied different forms of nozzles and their effect on the performance of vortex tube.

The nozzles recommended by Merkulov and Parulekar are simple in construction and nozzle tip is rectangular.  Merkulov recommended a tip area of 9% of the area of the cross-section of the tube, with the axial width to be twice the radial depth. Timothy found out that a convergent nozzle with both sides curved in opposite direction gave the best results. 

2.Diaphragm: -

 It is a cylindrical piece of small thickness.  It has a small hole of specific diameter at the centre.  Air stream traveling through the core of the hot side is emitted through the diaphragm hole.  Larger the diameter of diaphragm, smaller is the pressure drop and larger the ratio of mass of air emerging from the cold side to the mass of air emerging the tube in same time.  Smaller diaphragms will give maximum drop.  It should be placed as near nozzle as possible.  It was found by Alexeyev that a diaphragm with a circular concentric hole gives the best results.  He also found that, for maximum temperature drop, the diameter of the diaphragm must lie between (0.3 to 0.4) diameter of the vortex chamber (Dc).  Dr Parulekar and Timothy of IIT Bombay recommended and used a diaphragm of diameter 0.5 Dc. 

 3.Valve: -  

The valve obstructs the flow of air through hot side and it also controls the quantity of hot air through vortex tube. Timothy at I.I.T, Bombay investigated that, 19mm (2/4) needle valve oriented perpendicular to the axis of the tube gave better results.

4.Hot side: -  

It is a cylindrical in shape and circular in cross-section.  The length of the hot side tube of a vortex tube designed by Dr. Hilsch was bout 50 times the tube diameter.  Alexeyev tried hot ends of varying length on 16mm tube and has recommended the length of the tube as 50 times the diameter of the tube diameter same as Dr. Hilsch.  Merkulov reduced the length of the hot end. He had inserted a cross in the tube. This flow rectifiers serves as a vortex brake. This will reduce the energy loss due to friction of the hot stream. The optimum length of the hot end by him was (8 to 10) Dc (Tube diameter) Dr. Parulekar invented short vortex tube.  His hot end is consisting of three parts. 

1. A cylindrical or convergent piece of axial length equal to 6 mm. 

2. A divergent truncated cone with axial length equal to 18mm.

3. Cover, which also forms the third part of the hot side is cylindrical and of axial Length equal to 20mm.

 It was also found out that the roughness of internal surface does not seriously affect the results. 

Timothy at IIT found out that the hot ends with angle of divergence of 6.5 was giving best temperature drop while 10 angles was better for cooling effect. 

5. Cold air side: -

 This is the other side of the vortex tube.  Through this tube, cold air is flowing.  No valve is provided in this tube like hot air side tube. 

TEMPERATURE CONTROL

vortex tube temperature at it hot & cold end can be controlled by varying its different parameters such as 

1)Insulated and non insulated tube  

2)Cold orifice diameter 

3)Number of inlet tangential nozzle 

4)Diameter of tube.

1) Effect of insulation: -

Fig.4 (a) Cold tube

Fig.4 (b) Hot tube

Temperature and pressure of 290C and 3.5 bar respectively were made for the cold orifice diameter of 0.5D using the single inlet nozzle. The outside surface temperature of the non-insulated hot tube exposing to the surrounding was about 50- 600C, but this reduced to some 320C when using the insulated tube. The temperature differences between the inlet and the tube temperatures against various cold mass fractions are shown in Figures 4a and 4b for the cold and hot tubes, respectively. In the figure, the insulated tube provided higher temperature reduction than the non-insulated one. At a cold mass fraction of 0.345, the highest temperature reductions at the cold tube of the insulated and non-insulated tubes were 19 and 180C, respectively. In addition, in the hot tube the maximum temperature increases of the insulated and non-insulated tubes were found to be 24 and 20 0C respectively, at a cold mass fraction of 0.857. The average temperature 

differences between the insulated and non-insulated tubes were in a range of 2 to 30 0C for the cold tub and of 2 to 50Cfor the hot tube. This is because the insulated tube gave less energy loss to the surroundings than the noninsulatedone, causing the higher temperature difference within the tube. For the cold mass fraction ranging from 0.1 to 0.4, the temperature reduction in the cold tube increased, but then decreased for the cold mass fraction over 0.4. In the hot tube, for the cold mass fraction ranging from 0.1 to 0.8, the temperature proportionally increased, but then decreased rapidly for the cold mass fraction above 0.8.

2) Effect of cold orifice diameter: -   

                                                                  Fig.5

The experimental result of temperature drops for different cold orifice diameters ranging from 0.4D to0.9D using one inlet nozzle is depicted in Figure 5. The highest temperature reduction was achieved for all cold orifice diameters when the cold mass fraction was in a range of 0.3 to 0.4. Thus, the maximum temperature drop occurred if the cone valve was adjusted to let the cold mass flow rate leave the cold tube at 30 to 40% of the inlet air. The decrease in temperature in the cold tube was found to be 18, 19, 15, 14, 12, and 10 0C focusing cold orifice diameter of 0.4D, 0.5D, 0.6D, 0.7D, 0.8D and 0.9D at the cold mass fraction of 0.364, 0.375, 0.381, 0.378, 0.373, and 0.372, respectively. Furthermore, the cold orifice diameter of 0.5D yielded the highest potential of temperature reduction in the cold tube than the others. Using the cold orifice diameter ranging from 0.6D to 0.9D (bigger than that of 0.5D) would allow some hot air in vicinity of the tube wall to exit the tube with the cold air. Both the hot air and cold air as flowing out were mixed together which further affected the cold air to have higher temperature. On the other hand, for a small cold orifice diameter of0.4D, it has a higher backpressure and makes the temperature reduction at the cold tube lower.

3) Effect of number of inlet nozzle: -

Fig.6

The effect of the number of inlet nozzles on temperature reduction in the insulated vortex tube was experimentally investigated as shown in Figure 6.The increase in the number of inlet nozzles led to considerable temperature separation. In the figure, the use of 4 inlet nozzles resulted in a higher temperature reduction in the cold tube than that of 1 and 2 inlet nozzles for the cold orifice diameter of 0.5D. The highest temperature drops also were 19, 29 and 30 0C for using1, 2 and 4 nozzles, respectively. Mostly the maximum thermal separation occurred at a cold mass fraction between 0.3 and 0.4.Changing the number of inlet nozzles from 1 to 2 and 4 helped to speed up the flow And to increase the mass flow rate and strong swirl flow into the vortex tube. In addition, this gave rise to higher friction dissipation between the boundary of the flows and a higher momentum transfer from the core region to the wall region. This reduced temperature in the tube core while increased temperature in the tube wall area.

4) Diameter of tube: -

The vortex tube would offer considerably higher backpressures and, therefore, the tangential velocities between the periphery and the core would not differ substantially d for fixed inlet conditions (supply pressure), a very small diameter of to the lower specific volume of air (still high density) while the axial velocities in the core region are high. This would lead to low diffusion of kinetic energy which also means low temperature separation. On the other hand, a very large tube diameter would result in lower overall tangential velocities both in the core and in the periphery region, which would produce low diffusion of mean kinetic energy and also low temperature

separation.

 A very small cold orifice diameter would give higher back pressure in the vortex tube, resulting, as discussed above, in low temperature separation. On the other hand, a very large cold orifice diameter would tend to draw air directly from the inlet and yield weaker tangential velocities near the inlet region, resulting inflow temperature separation. Similarly, a very small inlet nozzle would give rise to considerable pressure dropping the nozzle itself, leading to low tangential velocities and hence low temperature separation. A very large inlet nozzle would fail to establish proper vortex flow resulting again in low diffusion of kinetic energy and therefore low temperature separation. The inlet nozzle location should be as close as possible to the orifice to yield high tangential 

velocities near the orifice. A nozzle location away from the orifice would lead to low tangential velocities near the orifice and hence low temperature separation.

WALL TEMPERATURE DISTRIBUTION

Fig.7 Arrangement of thermocouples along the hot tube wall

Wall temperatures of the hot tube were measured at 15 axial stations equally spaced along the axial distance downstream of the cold orifice plate as can be seen in Figure 7. Figure 8 displays the wall temperature distributions in terms of temperature difference between the wall and the inlet at different cold mass fractions. In a range from x/D=1 to x/D=11, the wall temperature distribution tended to increase, reaching a maximum at x/D=11. After x/D=11, the wall temperature distribution tended to decrease because the hot air near the tube wall region and the cold air in the core region were mixed together due to decaying of swirl flow close to the exit of hot tube. The temperature of the tube wall increased proportionally with the cold mass fraction, except when the cold mass fraction approached unity. It can be observed that at x/D=11, the temperature at the tube wall with 4 inlet nozzles was 780C above the inlet temperature for the cold mass fractions of 0.829.

COMPARISON OF THE PRESENT TUBE WITH THE PREVIOUS INVESTIGATOR

The details of geometries and working conditions of the present vortex tube and the previous work are shown in Table 1. Figure 9 displays the temperature reduction in the cold tube against the cold mass fraction for the present tube, Hilsch’s tube and Guillaume and Jolly’s tube. It is worth noting that the temperature reduction distributions for all tubes show a similar trend despite different tube sizes and inlet conditions. All tubes yield a maximum temperature reduction at the cold mass fraction between 0.3 and 0.4, having a maximum temperature decrease value at about 160C. 

A close examination reveals that when using a single tangential inlet nozzle, the temperature drop profile of the present tube is very close to that of Hilsch’s tube

but is slightly different with Guillaume and Jolly’s tube. This comparison has been made to help increase the confidence in the present measurements only.

Table 1. Comparison of the present tube with the previous investigator.

Fig 9. Comparison of temperature reduction in the cold tube

for the present work and previous work.

ADVANTAGES AND DISADVANTAGES

Advantages: -

1.Minor leakages are not important since air is used as a working substance. 

2.The vortex tube is quite simple in design.  The functioning of the vortex tube is also very simple.  This is so because; the hot/cold air is controlled with the help of the valve. 

3.The vortex tube has no moving parts and hence no maintenance is needed. 

4.It is light in weight. 

5.It is quite compact. 

6.It is possible to cool complicated space with the help of vortex tube. 

7.In initial investment it is cheaper. 

8.In order to operate this, no expert attendant is required. 

Disadvantages: -

Because of very low COP, the vortex tube is not suitable for large capacity refrigeration unit. 

APPLICATIONS

1.Cooling of cutting tools.  The vortex tube is best suited to cool the cutting tool in a workshop.  This is especially true for those materials for which, the use of coolant are not permitted. 

2.It is used to cool certain commodities at a low temperature of – 50 C by direct chilling.

3.Air suits.  Operators handling toxic gases use these suits.  These suits are using during spray painting, maintenance of pressure vessels etc. 

4.Vortex tube is also used and suitable for coalmine worker. 

5.The turbine blade needs cooling.  A vortex tube is used for that. 

6.The vortex tube is also used to cool the sample to be cooled and also to maintain the same sample at lower temperature. 

7.Since the vortex tube is able deliver cold and hot air simultaneously, it is used when heating and cooling requirements are simultaneous.  

8.Vortex tube can be used for shrink fitting where refrigeration is required for a short period. 

CONCLUSION

Pangjet Promvonge and Smith Elasma-ard of Thailand have carried out an experimental study on the temperature separation in the vortex tube and this research finding can be summarized as follows:

1)The increase of the number of inlet nozzles led to higher temperature separation in the vortex tube.

2)Using the tube with insulation to reduce loss to surroundings gave a higher temperature.

3)Separation in the tube than that without insulation around 2-30C for the cold tube and 2-50C for the hot tube.

4)A small cold orifice (d/D=0.4) yielded higher backpressure while a large cold orifice (d/D=0.7, 0.8, and 0.9) allowed high tangential velocities into the cold tube, resulting in lower thermal/energy separation in the tube.

Project On Automotion Noise and Vibration Control

ABSTRACT

The prime factors governing the automobile industry today are that of safety, efficiency and above all comfort, a lot of research has gone in to meet the above objectives. NVH is the industry term used to cover the subject of vibration and sounds.

Weight reduction of automobiles is necessary in improving fuel efficiency, but this would worsen the noise, vibration and harshness (NVH) characteristics of the vehicles, resulting in bad ride comfort. On the other hand, use of damping materials to improve the NVH characteristics would increase the weight of the vehicles, resulting in poor fuel efficiency. Important noise and vibration sources in automobiles are engine, “exterior air flow, road profile, and exhaust noise, power train noise. Among all these, the engine generated considerable noise and vibration in either running or standstill states, hence we can consider the engine one of the most important noise and vibration sources in automobiles. 

The main noise sources in the engine are the combustion noise, fuel injector noise, mechanical noise, inlet and exhaust noise, cooling fan noise from the ancillaries such as the generator or compressor. 

But in all the noise most of them so well attenuated. Hence engineering focus is switching to power train noise, road noise and tyre noise. Power train  noise is reduced largely by improvements in engines, transmission – housing and transfer core design, semiconductor technology that could lead to frictionless bearing and the possibilities using energy fields to transmit power verses solid media. 

In the following presentation we have focused on the recent development with the use of up coming material for cabin, have drastically cut down the noise level and also beefed up the fuel economy.


INTRODUCTION

Reducing noise, vibration, and harshness (NVH) generated in vehicles is a major priority within the automotive industry. Overall noise and vibration levels now are directly linked to vehicle quality. Development engineering are expending considerable effort to eliminate or reduce noise sources and determine their transmission path so the coupling of these sources to chassis modes can be eliminated.

NVH (noise, vibration, and harshness) is the industry term used to cover the subject of vibration and sounds. Unwanted sound regarded as noise. Vibration is typically felt rather than heard, and tends to be low frequency. Harshness usually means sudden events of short duration at higher frequencies.
During 1980 to 2000, the noise level inside a vehicle has been decreased by an average of 0.3 dB per year. As a vehicle gets quieter, the objective becomes one of tuning and balancing the sound rather than eliminating it, and new sources of noise become significant.

Older engine with a lumpy idle had a cam shaft with a lot of over lap, which was good for power and performance but bad for NVH. Also not all noise is bad. We want to manage the noise rather than eliminate it. Where it is very specific segment. Costumers for S- class Mercedes want an absence of noise.

We have more than 1000 NVH targets that fell into three main categories:-
1. Road Noise 2. Wind Noise    3.Power Train Noise                        

The main source of pass by noise had conditionally been the exhaust system but it is now so well attenuated that engineering focus is switching to power train and tyre noise. The new wide ratio, five speeds automatic transmission is dynamically balanced internally for enhance NVH characteristics. It provide further NVH benefits through increased power train stiffness with its 20 Kg(44-lb), one piece aluminum casting (rather than two piece aluminum casting on the previous model) for the transmission housing which is fully sealed.

CLASSIFICATION OF NVH


The classifications of NVH are:-

1.Road noise: - Road noise can be minimized by reducing air leakage, hence a noise path. Window and dual door seats that reduce air leakage by about 50% over the previous model. The vehicle’s body was also redesigned for less wind resistance by shifting the glass and door edge out of the air flow. Entering the passenger area include a dash panel made of laminated steel, a magnesium cross beam and additional sound insulation in the dash, rear quarters, wheel wells, hood fenders, pillars and drive shaft tunnel. For example, Ford conducted a road noise analysis of an early vehicle prototype that turned up a low frequency burst at a 37 and 49 Hz, which was traced to the rear roof panel and frame rail, minute vibration were attributed to the lift get glass, door panels, wind shield. As a result, the vehicle body mounts, rear frame tunning, rear roof adhesives were revised. According to company, the revised, microcellular body mounts-made of a vibration-damping combination of urethane and rubber as oppose to the previous, all-rubber mounts-alone reduced noise by 3.6 dB on average. All three modifications in combination to reduce interior sound by other 3 dB.

2.Wind noise: - Reduced wind noise created by slippery aerodynamics, muted engine and exhaust notes demanded by legislation.

3.Power steering noise: - Power steering noise and vibration are potential areas of costumer’s classification. These disturbances can manifest themselves in numerous ways- higher frequency vibrations as the ‘buzz’ felt through the steering wheel or the ‘chunk’ and ‘shudder’ as lock is applied and hydraulic ‘ moan’ that accompanies low speed parking maneuvers.
By employing noise path analysis and unique virtual test rig (UVTR) which predicts flow ripple in hydraulic systems. This allows engineers to predict fluid pulses and then minimize any vibration they might cause before the system is produced are installed in a vehicle.

4.Power train noise: - Power train noise is one of the major and latest problems for which engineers and researchers are looking for better and an economic solution. There are several researches had comes on this and many more to come. since the power train is a large vehicle subsystem mass, optimization of the engine mount system was seen as shake improvement strategy. Power train noise is reduced largely by improvements in engines, transmission-housing and transfer core design, semiconductor technology that could lead to frictionless bearing and the possibilities using energy fields to transmit power verses solid media. The process that proved effective in reducing lateral shake was to uncouple the power train lateral DOF from the other power train DOF s.

There are following ways to shake reduction:-

•Mount focusing, Stiffness roll axis, Focusing to uncouple DOFs ,Focusing process ,Revised mount system ,Evaluation of redesign,
Sources of ugly noise emanating from the power train, the road way and wind impact, design engineers cues on Neon 2000 ( soid as ply mouth Neon, Dodge Neon and chryster Neon)
Neon 2000 NVH attributes include:

•A higher volume muffler and an exhaust flex joint to make engine operation quieter.
•A four point engine mounts system to reduce steering wheel vibration at idle speed.
•Stiffer suspension cross members and controls arms to minimize the resonance from power train vibrations.
•Full frame doors (replacing glass roll up side windows) to form a tight-fitting body seal/noise barrier.
•All-season single ply tires (replacing previous Neon’s two-ply tires) to dampen road noise and beef up fuel economy.

PRESENT WORK AND INNOVATIONS:-

1.Material innovation
Many suppliers invest heavily in research to develop materials that will improve passenger materials that will improve passenger comfort, especially if considered in the early stages of design.

1.Elastically, from BASF, is an open-cell micro cellar polyurethane material that has high damping at high amplitudes, low damping at low amplitudes, and has good resistance to temperature extremes. Low lateral expansion and improved durability are other advantages over natural rubber.

2.It has developed an advanced acoustic interlayer for laminated glass that helps to optimize noise attenuation in the vehicle. Laminated glass is now being used in doors as well as windshields, and offers advantages over tempered glass-increased, intrusion resistance, reduced ultraviolet penetration, and reduced mass.

3.Quiet blend material is new blend of man-made and natural fibers that has demonstrated better sound absorption properties at lower mass than current fiberglass mat. The material will not melt or break down at typical engine and exhaust temperatures, it meets federal flammability guidelines, and low dust and fiber fallout means handling is easier.

4.Vibracoustic N.A. has developed a microcellular urethane material (MCU) for engine and body mounting, and a process for optimizing the material usage. The company also supplies other products such as linear mass dampers that can be tuned to attenuate unwanted vibrations, and a dual-mode crankshaft damper for engines.

5.Versa Mat is a family of thermal and acoustic insulating materials. Versa Mat 1000 is developed for interior applications, and versa mat 4800 is specially formulated for severe conditions. Improved acoustical and structural performance with lower mass is the advantages over traditional materials.

Vibracoustic’s answer to rubber engine mounts

Traditional product used for engine mounting is rubber,” and there has been no dramatic change to that material in decades.

Vibracoustics’ microcellular polyurethane (MCU) material isn’t new, either, but its application in engine mounts is. The foam product is “extremely durable, highly effective in insulation, and very flexible in its design and application to the vehicle”

The material’s primary use over the past 20 years has been in jounce bumpers, but the company is now looking at engine and body mounts as well as the coil spring. “It was found to be very effective and in some cases superior to rubber, It is up to 40% lighter than rubber.”

MCU has advantages in dynamics properties as well, In terms of dynamic stiffness, it’s more linear than rubber. Stiffness tends to increase as the frequency goes up with rubber. Not so with micro cellular polyurethane.”

“While conventional MCU degrades at lower temperature than rubber, an improved formulation outperforms rubber in high-temperature applications, now making it suitable for use in engine mounts, Testing of the “high-temperature MCU” is underway and the results to date have been great.

5: Polyurethane: one that it is eager to deploy is a polyurethane (PU) spray elastomer technology for dashboard insulators. “Cost, weight and acoustics are what we are looking for”, in dash board insulator “ is a technology for which the material and processes are repeatable and flexible”. 

The PU spray  elastomer has several advantages, it is said that over the most conventional material and method for making dashboard insulators: polyvinylchloride (PVC) and two step injection molding. The latter is a 12-step approach that involves moving the product several times during processing “It’s a dirty and time consuming process”. 

The comparison, the PU spray approach has only five steps in cell oriented process using a much smaller amount of floor space. Moreover, several of the steps are automated, resulting in reduced labor costs.

In the PU spray method, which is patent-pending, a robot applies a mold release agent and thin a thin coat of the polyurethane onto a tool located inside an injection molding machine. The robot then applies an additional layer on “acoustical hot spots.” It is finding that the process in some cases works better when the hot spots are treated first, with the second layer being applies  to the entire tool.

The mold then closes, and immediately sound-absorbing foam is injected. Shortly after these two automated operations, the mold reopens, and the dashboard mat is removed manually for trimming via water jet or 3-D die. Whereas the process uses a single injection molding machine for two operations, competing approaches use two machines-one for making the insulator mat and other to make foam sound absorbing sheet.

Preformed sheet foam sound absorbing material is popular because it is inexpensive to produce. But what the customers will most appreciate about the PU spray technology. It is ability to apply the elastomer material in varying thicknesses according to the specific application. All that need be done to accomplish this is reprogramming of the applicator robot. 

This feature will have special appeal that uses multiple engine/transmission combinations on a particular vehicle. Rather than use one dashboard insulator with uniform mat thickness for all vehicles, variable thickness technology allows for production of mats that are matched in mat material thickness to the specific noise profile produced by each power train configuration. The robot applicator can be programmed for extremely precise application thickness.

We will need to make sure that our sheet metal is within tolerance because the definition of the mat is good. Typically with PVC parts…… their may be some gaps and variances. It is interesting that of the eight dashboard mats as part of its research, non featured variable thickness even though that is possible (although expensive) with the injection molding method most often used at the moment. Another advantage is that it provides for better sealing of grommets, which are installed on the mold tool prior to application of the spray, the grommets is actually built into a mat when the spray coat is applied. 

ADVANTAGES OF REDUCING NVH ;

There are many advantages of reducing NVH. But some are listed below:-

• It improves vehicle quality.

• Mechanical parts life can be increased.

• By reducing vibration the pay of is not only comfort but also fuel economy improvements.

• Vehicle’s weight-saving beef up fuel economy.

• Quality drives can be achieved. 

• Safety and security are also enhanced.

• Reduce noise pollutions.

• Improves sound quality reduces human fatigue.

• Performance, handling and overall styling can be enhanced.

CONCLUSION

As we know that researches are going on to reduce NVH in the vehicle. There has been significant breakthroughs  in this field and further improvements are coming on. Development engineering are expanding considerable effort to eliminate or reduce noise sources and determine their transmission path so the coupling of these sources to chassis modes can be eliminated. The new development have eliminated problems of the previous one like first PVC was used as a NVH reducing material but now PU is a new material which has many advantages, like, automation results in reduced labor cost, easy method of production, sound absorbing foam, less cost of production as compared to PVC. In  coming years  there will be the use of predictive method /model to solve NVH that will enable us to conduct noise screening on the computer using entire system models, before prototype parts are built. As Engine accelerates through higher and higher rpms electronics could be used to null and void certain frequencies that  occur  only at certain rpm,  which is different from passive resonators that only address one noise frequency. By using electronics to cancel or enhance sounds, plastic hollow resonator could be eliminated.