a first speed detecting means detects whether the engine speed has fallen below a prescribed level . a second speed detecting means detects whether an accelerator pedal angle has been changed at a speed higher than a predetermined value . a third speed detecting means is provided to detect whether the speed of the automobile is equal to , or higher than , a predetermined value . upon receipt of the output signals from the first , second and third speed detecting means , a solenoid drive circuit drives engine vibration absorbers for a predetermined period of time . more specifically , the circuit energizes solenoids for this period . the solenoids rotate the thus rotary valves of the absorbers , thus closing the orifices of the absorbers . as a result , the absorbers generate great forces damping the back - and - forth motion of the engine . the vibrations of the engine are therefore not transmitted to the chassis of the automobile .