| 摘要 |
<p>In an ic engine which is to operate with a lean air-fuel ratio at normal loads and with a stoichiometric air-fuel ratio at high loads, a rapid, imperceptible change between the two conditions is effected by the provision of a supply of diluting air to the intake manifold 20 via a bypass pipe 30, 32 in addition to the metered quantity supplied through the main throttle 28. During such a change the output power of the engine is substantially unchanged since the quantity of fuel supplied to the engine is determined in accordance with the metered quantity of air passing the main throttle valve 28 which is itself substantially unchanged by the addition of the bypass air. The bypass valve 38 is mechanically linked to the main throttle valve 28 so as to move in synchronism therewith. EGR gases may be used to provide a dilution of up to 20%. Beyond this additional air is provided through the bypass pipe in accordance with a two way valve 34. <IMAGE></p> |
