VTEC System Description - Overview
The VTEC system improves fuel efficiency and reduces exhaust emissions at all levels of engine speed, vehicle speed, and engine load. The VTEC mechanism changes the valve lift and timing by using more than one cam profile.
The i-VTEC system provided in this engine is a system to switch the valve control depending on the running status to two stages of a normal valve control and an all-cylinder valve stop control. In the normal valve control, the intake and the exhaust valve operate to allow the vehicle to run based on the engine torque or the engine torque + IMA motor assist depending on the running conditions. This is for the purpose of providing an improved running performance and improved fuel consumption. In the all-cylinder valve stop control, the operations of the intake and the exhaust valve are stopped and the vehicle is allowed to run based on the IMA motor torque. By stopping all cylinders, exhaust emissions and friction losses are reduced and the regenerative energy of the IMA motor is improved leading to improved fuel consumption.