| 摘要 |
<p>The fresh air heating and ventilation system for the bus has foot level ducts to warm recirculated air, and face level ducts (6) which provide a variable ratio of recirculated and fresh air. The two systems have separate heat exchangers while the top system has a control flap (8) to control the ratio of fresh and recirculated air. The operation of the fresh air flap is also controlled in relation to the heat supply available from the heat exchangers. A control ensures that the heat drawn does not cause the engine coolant etc. to become too cool for the efficient operation of the engine.</p> |
