Abstract
New 4-cylinder V-type engine has been developed with a concept of compact, low-vibration and pulse feeling. Traditional 4-cylinder 90-degree V-type engine places #2 and #4 cylinders on the V-type front bank while on the rear bank, it places #1 and #3 cylinders. On the other hand, new 76-degree V4 engine places #1 and #4 cylinders on the front bank while on the rear bank, #2 and #3 cylinders are placed for right-left symmetry. By adopting the OHC mechanism in which the intake valve is directly pressed by one cam and the exhaust valve is driven by the locker arm, higher rotation and output are enabled than those in traditional OHC engine while compared with a DOHC engine, the exhaust section at the top of cylinder head becomes compact, thereby reducing the longitudinal length of engine. The engine with V-bank angle of 76 degree can eliminate a primary vibration theoretically without the use of balancer by setting the crank pin phase to 28-degree.