| 摘要 |
PURPOSE:To prevent vapor lock which generates in high temperature range by varying the valve-opening set pressure for a valve body by controlling in variable ways the environmental temperature of a spring made of shape memory alloy, according to the engine operation state. CONSTITUTION:In the idling range in the state where the engine temperature is higher than a prescribed value or in the operation range where the possibility of generating vapor-lock is high as on restart, a heater 21 is put into electric conduction through a harness 22. Then, the environmental temperature of a sub-return spring 20 made of shape memory alloy is raised. When the environmental temperature of the sub-return spring 20 rises over 80 deg.C, the sub-return spring 20 sharply extends to increase spring constant. Then, the urging force in the direction for opening a valve body 15 increases, and the fuel pressure increases, and fuel atomization is suppressed to prevent vapor lock. |
