Abstract: An ignition switch is turned on, and when an abnormality is detected in any of electronic control instruments or sensors, real failure is established, and a fail-safe process is performed. After a lapse of a predetermined period from the establishment of the real failure, fault determination is established, a failure level is sent, and a hybrid fail-safe process is performed. Then, when the abnormality is eliminated, the real failure is not established, and the fail-safe process of an engine is finished. Then, when the ignition switch is turned off and then again turned on, sending of the failure level to a hybrid control unit is stopped, and the hybrid fail-safe process is finished.

Abstract: An ignition switch is turned on, and when an abnormality is detected in any of electronic control instruments or sensors, real failure is established, and a fail-safe process is performed. After a lapse of a predetermined period from the establishment of the real failure, fault determination is established, a failure level is sent, and a hybrid fail-safe process is performed. Then, when the abnormality is eliminated, the real failure is not established, and the fail-safe process of an engine is finished. Then, when the ignition switch is turned off and then again turned on, sending of the failure level to a hybrid control unit is stopped, and the hybrid fail-safe process is finished.

Abstract: A valve seating noise discriminating system discriminates valve seating noises caused by valves of a valve system in an engine from noises caused by knocking. Ignition timing can be prevented from being erroneously retarded due to the valve seating noises. A variable valve operation control unit A1 selects one of a plurality of valve operation modes. A knocking detecting unit A2 detects vibrations equivalent to knocking and issues a knocking present signal K. A valve seating noise discriminating unit A3 discriminates a valve seating noise when a level of a first knocking present signal K meets a predetermined requirement. When it is in a standby state, a cylinder number storage A4 stores a cylinder number associated with the first knocking present signal K when the valve seating noise discriminating units discriminates the valve seating noise.

Abstract: A fuel control device comprises a pair of valve change-over units KL and KH, an operation mode setting unit A1 for setting an engine in either a partial or full cylinder operation mode as a target operation mode according to engine operation data, a valve change-over controller A2 for controlling the valve change-over unit KL or KH to establish the target engine operation mode, a fuel supply unit FS to selectively supply fuel to active cylinders in the target engine operation mode, a mode change confirming unit A3 for confirming whether or not the engine is switched from the partial cylinder operation mode over to the full cylinder operation mode and issuing a mode change confirming signal, and a fuel supply controller A4 for operating the fuel supply unit FS in the partial cylinder operation mode when the partial cylinder operation mode is not successfully changed over to the full cylinder operation mode.