multi valve engine

8/10/2019 multi valve engine

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SEMINAR

ONMULTI VALVE ENGINE

PRESENTED BY:

Vikram Vijayant Rana

www vijayantrana co cc

MECHANICAL ENGG.


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CONTENTS

Introduction

History

Classification of multi valve engine

Working principles

Advantages Disadvantages


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INTRODUCTION

In automotive engineering a multi-valve or multivalve engine is one where eachcylinder has more than two valves. A multi-valve

engine has better breathing and can operate athigher revolutions per minute(RPM) than a two-valve engine, delivering more power

Multi-valve engines started life in 1912 on aPeugeot GP racing car.


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HISTORYMulti-valve engines started

life in 1912 on a Peugeot GPracing car. It was then briefly

used by the pre-war Bentley

and Bugatti. However, mass

production on road cars cameas late as 1970 - Triumph

Donomite Sprint (1973),

Chevrolet Cosworth Vega

(1975), Lotus Esprit (1976),

Abarth (1976) and BMW

(1979) were the earliest

adopters.


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CLASSIFICATION OF MULTI VALVE

ENGINES

3-valve engines

4-valve engines

5-valve engines


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3-VALVEENGINES

The earliest mass

production multi-valve

engines were 3-valves

because of its simple

construction - it needsonly a single camshaft to

drive both intake valves

and the exhaust valve of

each cylinder. Today,there are still some low-

end cars using this cheap

but less efficient design


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4-VALVE ENGINE

Most 4-valve engines employ twin-cam for its obvious

benefits, for instance, cross-flow intake/exhaust, low inertia

and friction, and the allowance of independent intake and

exhaust variable cam phasing.

This is the most common type of multi-valve head, with

two exhaust valves and two similar (or slightly larger) inlet

valves. This design allows similar breathing as compared to

a three-valve head, and as the small exhaust valves allowhigh RPM, this design is very suitable for high power

outputs

Today, by far the majority of multi-valve enginesemploy 4 valves per cylinder.


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5-valve engines

Less common is the five-valve head, with two exhaust valves

and three inlet valves. All five valves

are similar in size. This design allows

excellent breathing, and, and as every

valve is small, high RPM and very highpower outputs are available.

Yamaha was the expert of 5-valve

technology. Since it had been using 5-valve technology on its

high-performance motorcycles. In 1991, it helped Toyota to

produce a 1.6-liter 20-valve engine for Corolla Levin (Trueno).


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Advantages

it increases the coverage of valves over the

combustion chamber, allowing faster breathing

thus enhance power at high rev.

It allows the spark plug to be positioned in the

center of combustion chamber, enabling quickerflame propagation, more even and more efficient

burning.

Using more but smaller valves instead of two large

valves means lower mass for each valve. Thisprevent the valves "float" from its designed position

at very high rev, thus enabling the engine to rev

higher and make more power as a result.


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Reduced fuel consumption.

Multi valve combustion.

Greater pick up.

Optimized valve timing.

Higher torque over the entire range of

engine speed.


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Disadvantages

multi-valve engines use morecomponents, thus they carry more

weight and higher costs.

At low to medium rpm they actuallyproduced less torque than the

equivalent 2-valve engines.


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THANK YOU

multi valve engine

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