Method of transferring signals within electronic control system for internal combustion engines

DETAILED DESCRIPTION It is therefore the object of the invention to provide a method of transferring signals within an electronic control system for internal combustion engines, which enables precise and complicated control of a plurality of items such as fuel injection quantity and ignition timing, and also enables data transfer between CPU's without incurring complication of the system construction and other inconveniences as well as of the control programming, to thereby make the best of a limited number of CPU terminals.
According to the invention, the above object is attained through a method of transferring at least one signal between a first central processing unit provided in an electronic control system for controlling fuel supply to an internal combustion engine and a second central processing unit provided in the electronic control system for controlling ignition of a mixture supplied to the engine, wherein a value of at least one operating parameter of the engine is detected, and the detected value of the at least one operating parameter is used both for controlling the fuel supply to the engine and for controlling the ignition of the mixture supplied to the engine.
The method is characterized by comprising the following steps: connecting at least one signal transfer line between the first and second central processing units; causing one of the first and second central processing units to produce a digital signal representing the detected value of the at least one operating parameter; and causing the one of the first and second central processing units to transfer the digital signal to the other central processing unit through the at least one signal transfer line in a start-stop serial manner.
Preferably, data consisting of a predetermined number of bits is produced as the digital signal in the one of the central processing units in the one central processing unit; serializer means is provided in the one central processing unit and transforms the data into a sequence of pulses, of which each pulse corresponds to respective one of the bits, and also transfers the pulses one by one to the other central processing unit through the signal transfer line; and deserializer means is provided in the other central processing unit and transforms the sequence of pulses transferred thereto back into data consisting of the predetermined number of bits