| 摘要 |
<p>PROBLEM TO BE SOLVED: To lower a load of a transmitting mechanism for transmitting the rotary force of a crank cam shaft to a cam shaft so as to prevent the lowering of useful lifetime. SOLUTION: An engine 11 is provided with an intake cam shaft 24, an exhaust cam shaft 25 and a crankshaft 17. A timing belt 33 is wrapped around cam pulleys 30, 31 of each cam shaft 24, 25 and a crank pulley 32 of the crankshaft 17. Each cam shaft 24, 25 drives for opening and closing an intake valve 21 and an exhaust valve 21 through valve cams 26, 27. The other end of the exhaust cam shaft 25 is provided with a pump cam 41 for driving a fuel injection pump 40. Phase of this pump cam 41 is set so that the fluctuation of torque to be generated in each cam shaft 24, 25 is offset by the driving reaction force to be generated in the exhaust cam shaft 25 at the time of driving the fuel injection pump 40.</p> |
