ENGINE UNIT

A high-expansion cycle (Atkinson cycle) is used to improve heat efficiency.

On the intake side, Variable Valve Timing-intelligent Wide (VVT-iW), which optimally controls the intake camshaft (camshaft) according to driving conditions, is used.

A timing rotor for the camshaft position sensor is provided at each back end of the intake and exhaust camshafts.

The No. 1 valve rocker arm sub-assembly is used as a valve mechanism and by achieving size reduction while drastically reducing the amount of friction that occurs between the sliding parts and cams, low fuel consumption is achieved. Also, an oil pressure type valve lash adjuster assembly is used to make valve clearance adjustment unnecessary in consideration of serviceability.

A valve spring, whose upper portion is shaped like a beehive, is used to reduce inertial mass. As a result, the load on the valve spring and friction are reduced.

Together with the use of the No. 1 valve rocker arm sub-assembly, the cam profile has been designed with an indented R (radius). This results in increased valve lift when the valve begins to open and finishes closing, helping to achieve enhanced output performance.

The No. 1 valve rocker arm sub-assembly has been made thinner to reduce the thickness of the cam lobe, achieving valve system weight reduction.

The intake camshaft uses a structure that allows a vacuum pump to be operated.

The pump cam used to operate the fuel pump assembly (for high pressure) is built into the camshaft on the exhaust side. Also, a pump cam with 3 peaks is used, and by synchronizing fuel pressure-feeding and fuel injection, the difference in fuel pressure between cylinders is reduced.