Denso Corporation

Takahiro Joko

Yasuhiro Tanaka

Yoshiharu Takeuchi

Yoshifumi Ozeki

Hidemasa Miyano

The engine ECU includes a control CPU and a monitoring CPU. The control CPU has a vehicular engine control function and an electronic throttle control function. The monitoring CPU is connected to the control CPU in an intercommunicative manner. The monitoring CPU communicates with the control CPU to receive data at least on the throttle control from the control CPU. The monitoring CPU determines whether the data from the control CPU is properly received. If the date is not properly received, the monitoring CPU resets the control CPU.

Electronic control device having control and monitoring cpus

An engine ECU comprises a control CPU for executing engine control and a watchdog circuit for monitoring the CPU. The watchdog circuit stores, whenever a reset signal is outputted to the CPU, a reset information indicating a fault record. The CPU executes, after it is once reset and re-started, the predetermined fail-safe process based on the reset information stored. When a monitor CPU connected to the control CPU for making communication is used as the watchdog circuit, fault detection times X and Y are specified to satisfy the relationship of X&gE;Y, when the communication fault detection time is defined as X and the watchdog pulse fault detection time as Y.

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Toyota, Japan

Takahiro Joko