| 摘要 |
A variable compression ratio (VCR) would enable better efficiency of four-stroke internal combustion engines. The invention relates to modifications to said engines in order to vary the compression ratio in a continuous mode. The invention comprises adding, on the side of each cylinder, one or more auxiliary combustion chambers connected by a valve-controlled duct to the conventional combustion chamber. The valve of the auxiliary chamber is open at the beginning of the compression phase and is closed according to a variable setting during this same phase. The angular setting of the closing of the valve of the auxiliary combustion chamber mainly depends on the density of the drawn air and on the target compression ratio for the ignition. Said differential compression phase results in a variable portion of the air being redirected towards the auxiliary chamber, and leaves the necessary amount of air to be compressed in the conventional chamber, which makes it possible to control the compression ratio in the conventional combustion chamber for ignition. After ignition, the valve of the auxiliary combustion chamber is opened again so that the burning mixtures can mix with the gases in the auxiliary combustion chamber so as to carry on the cycle with the expansion. Said system offers flexibility in the angular setting of the optimal compression and in the variable angular setting of the ignition, thereby offering possibilities of optimising the driving phase.
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