| 摘要 |
PURPOSE:To heat a riser section of an intake pipe promptly and to thereby improve the engine starting performance, by forming a riser heating water passage in the intake pipe, and communicating the passage with a water jacket for cooling an engine and a cooling water storing, heat-insulating tank. CONSTITUTION:In case of cold starting of an engine, changeover valves 7, 8 are shifted by a control unit 13 such that their ports 7b and 7c and ports 8b and 8c are respectively communicated with each toher. At the same time, a water pump 10 is set into operation and a changeover valve 9 is closed. Resultantly, the temperature of a riser section 2a can be raised by feeding cooling water kept at a relatively high temperature in a cooling water storing, heat-insulating tank 5 to a riser heating water passage 4. By thus promoting vaporization of fuel supplied from a carburetor 1, engine can be warmed up efficiently without causing misfiring. Subsequently, when the temperature of cooling water has become higher than a prescribed value, the valves 7, 8 are shifted such that their ports 7a-7c and 8a-8c are all communicated with each other. At the same time, operation of the water pump 10 is stopped and the changeover valve 9 is closed. |
