New 8-Bit Microcomputer for Transmission Control 891319
The progress of electronic technology, especially in the field of microcomputer application, is leading to better performance and more advanced functions in automotive electric control systems. The most modern microcomputer control technology has been adopted in many subsystems, such as:
Engine control systems
Transmission control systems
Antilock brake control systems
Instrument panel systems
For example, in transmission control systems, engineers are working to achieve better compatibility between more advanced electronic circuits and hydraulic control systems in order to boost transmission efficiency.
As one example, in the lock-up mechanism control system now in use, simple intermittent control is performed, but in order to obtain a smoother gear change, PWM (Pulse Width Modulation) control has been developed.
Along with this change, a linear solenoid valve which linearly changes the hydraulic pressure to control the lock-up clutch has come to be used in the hydraulic circuit, so a PWM function has been added accordingly in the electric circuit.
Thus, as higher performance automatic transmission. units have come into use, the input-output pulse signals has been increased in electronic circuits, and the on-chip timer/counter hardware system of conventional 8-bit microcomputers has become inadequate.
In this paper, we will describe about the functions of the electronic circuits necessary to control automatic transmission devices.
Next, we will introduce an example of a transmission control system which fully satisfies such functions those mentioned above by utilizing the µPD78214, a new 8-bit microcomputer with on-chip powerful timer/counter hardware.