Five-valve Cylinder Head
There has been in the vehicle history only one piston-stroke engine featuring more than five valves sensibly. However, it was so complicated that it disappeared again after a short while. The engine had oval pistons and therefore enough space in the cylinder head. This is different for the one illustrated on top.
There are differences in the interpretation of whether the expenditure pays off. The manufacturer claims advantages for the performance provision and the mileage. Testers have difficulties to track this.
How it works
Because the intake is more difficult than the exhaust, the solution is to design the inlet side a little bigger than the outlet side. In this case they simply take three intake valves and two exhaust valves. So far so well, but how to control all these valves? You take exactly like with four valves double overhead camshafts, keeping the same separation of inlet and outlet. If you take a close look at the intake valves on the (enlarged) picture, you will recognise for the lower ones a different work angle because it must also reach the common camshaft.
Unfortunately, there is hardly a future for the aesthetic beauty of this cylinder head. The petrol direct fuel injection system is claiming space. An injector must fit into the cylinder head, thus the fifth valve disappears again. 06/08
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