| 摘要 |
<p>The vehicle heater is provided with hot water from the coolant system, with the flow of the hot water controlled by a vacuum servo operated valve (8). The amount of force required for the water flow valve is greater than could be supplied by the vacuum level in emission control systems and a special high response non-return valve (29) is incorporated between the inlet manifold and the servo (15). The non-return valve is set so that it only opens on the suction stroke of the engine. The valve has to open and close at a fast rate and special valve diaphragm is used for this. The action of the valve can also be controlled by a solenoid, with a rapid acting facility. Sufficient vacuum level is thus provided in all states of the engine operation.</p> |
