Thermostatic Air Intake
The fresh air flap is controlled by the accelerator linkage and starts to open at a throttle valve angle of 20°. At about 60° angle, the flap is opened completely and closes off the warm air channel. The thermostat causes the warm air flap to begin closing at 104°F and flap is completely closed at 131°F. During normal running, the warm air flap fluctuates according to the temperature of the preheated air and the throttle opening. The intake air therefore maintains itself at about 100°F.