The presentation includes the information about multi valve engine technology. The presentation include the types of multi valve engine with pictures, advantages and disadvantages.
3. A multi-valve engine has better breathing and can operate at higher revolutions
per minute(RPM) than a two-valve engine, delivering more power
Multi-valve engines started life in 1912 on a Peugeot GP racing car.
INTRODUCTION
4. HISTORY
Multi-valve engines started life in 1912 on a Peugeot GP racing car. It was then briefly used
by the pre-war Bentley and Bugatti. However, mass production on road cars came as late as
1970 - Triumph Dolomite Sprint (1973), Chevrolet Cosworth Vega (1975), Lotus Esprit
(1976), Abarth (1976) and BMW (1979) were the earliest adopters.
5. CLASSIFICATION OF MULTI VALVE ENGINES
MULTI VALVE
3 VALVE
ENGINE
4 VALVE
ENGINE
5 VALVE
ENGINE
6. 3 VALVE ENGINES
The earliest mass production multi-valve engines were 3-valves because of its simple
construction - it needs only 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
7. 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 allow high RPM, this design is
very suitable for high power outputs
8. 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 high power 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).
9. 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 quicker flame propagation, more even and more efficient burning.
➔ Using more but smaller valves instead of two large valves means lower mass for
each valve. This prevent 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.
10. ➔ Multi-valve engines use more components, thus they carry more weight and higher
costs.
➔ At low to medium rpm they actually produced less torque than the equivalent 2-
valve engines.
DISADVANTAGES