| 摘要 |
PURPOSE:To decrease a combustion noise by providing an intake air preheating pipe bypassing an intake pipe arranged beside an air cleaner and mounting a heat exchanger on the intake air preheating pipe which heats the intake air by the heat of exhaust gas, thereby the intake air preheating is carried out. CONSTITUTION:While the engine is idling, a power signal is inputted to valves 14, 15 through an AND gate 20 based on the outputs from an idle position detector 18 connected to a fuel injection rate control link 17 of a fuel injection pump 16 and a speed sensor 19. As a result, a passage 12 is opened whereas another passage 13 is closed, and therefore, the negative pressure from a negative pressure pump 21 is introduced into a negative pressure chamber 10 of an accumulator 8 so as to displace a diaphragm leftward against the force of a spring 11. As a result, a swith valve 6 closes the intake pipe 1 via a valve rod 7, communicating the intake air preheating pipe 3. The air thus led into the preheating pipe 3 is preheated by the exhaust gas through the heat exchanger 5 while it is passing therethrough and then supplied to a combustion chamber of the engine. |
