| 摘要 |
An internal gas transfer method for operating an engine with at least a first and a second intake port controlled by respective first and second poppet valves normally timed to open and close during the intake period of the engine cycle. Variable valve timing is provided for at least the second poppet valve, and a non-return valve is mounted in the second intake port positioned such that the valve automatically shuts in the flow direction away from the engine cylinder when the said port and the non-return valve are subjected to a pressure higher than the intake air supply pressure. An auxiliary chamber is provided which communicates with the cylinder via the second intake port and downstream of the non-return valve. When internal gas transfer is required, the second poppet valve is moved in timing to open and close during a period other than the air intake period of the engine cycle, thus briefly connecting the second intake port and non-return valve with the engine cylinder, shutting the said non-return valve, and permitting transfer of gas between the cylinder and the auxiliary chamber during the power conversion phase of the engine cycle.
|
