PURPOSE: To contrive to reduce vibration and noise, by a method wherein a pressure sensor for detecting the pressure inside a combustion chamber is provided, and the opening of an intake throttle valve is controlled according to the pressure.
CONSTITUTION: An injection pump 7 is provided with a control lever 10 for controlling the injection amount, and the pressure sensor 11 is fixed to the combustion chamber 3. A projection 7b for detecting a reference signal 7b is provided on a driving gear 7a for the injection pump 7. A main intake passage 5a and an auxiliary intake passage 5b are provided on the upstream of an intake pipe 5, and a main intake throttle valve 12a and an auxiliary intake throttle valve 12b are located in the passages 5a and 5b, respectively. When the maximum combustion pressure is not lower than a preset pressure value, the opening of the auxiliary throttle valve 12b is gradually reduced by a predetermined amount in each predetermined period, and when the maximum combustion pressure is lower than the preset pressure value, the opening of the valve 12b is gradually enlarged. Accordingly, the air amount can be controlled accurately, and it can be contrived to reduce the vibration and noise.
KAWAI HISASHI
ITOU TOSHIHIKO
TANAKA TAKESHI
