COMPRESSION RATIO ADJUSTMENT DEVICE FOR A COMBUSTION ENGINE AND METHOD FOR CONTROLLING THE COMPRESSION RATIO ADJUSTING DEVICE FOR A COMBUSTION ENGINE

摘要

It is an object of the present invention to provide a novel compression ratio adjusting apparatus for an internal combustion engine which can improve a knocking resistance performance and can prevent or reduce a temperature increase of the exhaust gas. The compression ratio adjusting device is configured to relatively reduce a mechanical compression ratio in a high load region of the internal combustion engine while also setting a mechanical expansion ratio to a relatively high ratio. With this configuration, the compression ratio adjusting apparatus performs control for decreasing the mechanical compression ratio in the high load region of the internal combustion engine and further increasing the mechanical expansion ratio to improve the knocking resistance performance and prevent or reduce temperature increase of the exhaust gas, thereby causing thermal damage can be avoided on a part in the exhaust system.