| 摘要 |
An exhaust braking control apparatus for use with an automotive vehicle having an engine and an automatic transmission. The exhaust braking control apparatus includes a control valve situated for movement within an engine exhaust passage to control exhaust gas flow from the engine to the atmosphere. A control unit is provided to produce an engine braking command signal when the automatic transmission is in low gear for engine braking. In the presence of the engine braking command signal, the control valve moves in a closing direction to provide an engine braking effect. The control unit includes an inhibit circuit arranged to interrupt the engine braking command signal during a gear change produced in the automatic transmission from a higher gear to a lower gear. Such a change down is produced when the vehicle speed is less than a reference value. In the event of failure of the inhibit circuit, the reference value is changed to a smaller value.
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