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The global warming has been recognized as a potential hazard in the 21st century and all the power plants are asked to be more clean and energy saving, which is still the toughest problem. On the other hand, people are more anxious about the quality and longer useful life and higher maneuverability of their cars. A so called “Intelligent Engine” must become a reality in the not-too-distant future. Progress in the technologies of the three major elements of the engine control: (1)Sensors and Actuators (2)ECU (3)Control strategies continues. The application of modern control theory offers the big advancements and it expands from engine itself to the engine/vehicle system. As for sensors, combustion pressure sensors may become one of the key sensors for directly defectomg the fundamental signal from the mechanical phenomena of the engine.

Electronic Control Units (ECUs) for automobiles are usually composed of a main single-chip microcomputer and peripheral circuits with some standard and/or custom ICs. The peripheral circuits vary with the kinds of control or models of automobiles. When the peripheral circuits are replaced with a single-chip microcomputer, the ECU becomes compact and low in cost. This is because the ECU is constructed with only two LSIs and can be used for various kinds of control and various models of automobiles only by changing the program of the microcomputer. The microcomputer, however, requires many I/O functions and high reliability. We have developed a new 4-bit microcomputer suitable for these requirements. The new microcomputer has two remarkable features. One is powerful I/O functions such as high speed I/O, serial I/O, parallel I/O, analog I/O, and default output that is generated in place of the calculated output by the main CPU when it fails.

In the fall of 1984, Toyota marketed a new engine control system through the use of a commercial single-chip microcomputer. Engine control functions have been optimally allocated between the system's hardware and software, and three new circuit modules have been developed for the calculation of basic injected fuel amount, and knock control, ignition control. This has resulted in a large scale reduction of the load on the system's microcomputer, which has made the use of commercially available microcomputers possible, thus cutting costs while at the same time increasing the functions and reliability of the system.

Toyota succeeded in the fall of 1984 in manufacturing a complex engine and transmission control system using a newly developed single-chip microcomputer. This microcomputer, equipped with an 8K-byte ROM ( Read Only Memory) and a 256-byte RAM ( Random Access Memory), a powerful real time processing function, and a high-speed optimum instruction set, is better suited for automobiles. Application of the latest CMOS technology has enabled lower power consumption and improved noise immunity. The new system, which includes a new function; the electronic spark advance with knock control in addition to the conventional sophisticated system, has greatly improved the performance and driveability of vehicles.