Precision Control Technology for Automotive Engines

Masaaki Fujisawa, Automotive Products Division, Hitachi, Ltd.
Masami Nagano, Automotive Products Division, Hitachi, Ltd.
Toshio Ishii, Automotive Products Division, Hitachi, Ltd.
Masakatsu Fujishita, Automotive Products Division, Hitachi, Ltd.


Automotive engine control has several simultaneous requirements, such as purifying exhaust gases and reducing fuel consumption to protect the global environment and enhancing power performance and silencing noise to make motor vehicles more comfortable and safer. These requirements can be satisfied only through more precise analysis and control of engine behavior.

To that end, we have developed new control systems, including:

(1) a model-based control system that models the behavior of air and fuel supplied to the engine and, based on that model, precisely controls the air/fuel ratio in order to purify exhaust gases;

(2) a digital knock detection system that analyzes the frequency of vibration waveforms of engine knocking and thereby detects the knock precisely, all on a real-time basis, in order to improve fuel efficiency;

(3) an on-board diagnosis technology that conforms to the California OBD-II regulations; and

(4) an active ignition timing control system to attain better drivability.

In order to realize these controls for on-vehicle use, we also developed a compact engine control unit with densely mounted electronic components, including a high-performance single-chip microcomputer.

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