Cylinder Identification (CID)
An cylinder identification sensor is used to identify cylinder firing sequence. The sensor is connected around the HT lead of
cylinder number 4 (4 cylinder) or cylinder number 6 (6 cylinder) adjacent to the distributor. As the HT pulses travel along the HT
lead, a small AC signal is induced in the sensor and returned to the ECU. The ECU utilises an ADC to transform the signal into a
digital pulse.
Fuel injection
The Motronic ECU contains a fuel map with an injector opening time for basic conditions of speed and load. Information is then
gathered from engine sensors such as the AFS, CAS, CTS, and TS. As a result of this information, the ECU will look-up the
correct injector pulse duration right across the engine rpm, load and temperature range.
The injectors are arranged in two banks with injectors 1 and 3 (4 cylinder) or 1, 3 and 5 (6 cylinder comprising one bank, and
injectors 2 and 4 (4 cylinder) or 2, 4 and 6 (6 cylinder) making up the other bank. Each bank is connected to the ECU via an
independent ECU pin.
The Motronic 1.1 & 1.3 multi-point injection system pulses the injectors semi-sequentially and once every two engine revolutions.
During engine start-up below 600 rpm the ECU pulses all injectors simultaneously. Once 600 rpm has been attained and if the
ECU has received a signal from the CID sensor, each injector bank will be pulsed alternatively according to which pair of
cylinders are approaching TDC. If a signal is not received from the CID sensor the injectors will remain on simultaneous
operation. However, if the CID sensor subsequently sends a signal to the ECU after the engine has commenced running, the
ECU will pulse the injectors semi-sequentially after the next deceleration phase - even if the CID sensor then ceases to send a
signal.
During start-up from cold, injector pulse duration is increased to provide a richer air/fuel mixture and pulse frequency is also
increased. In addition, the ignition timing is also retarded. Injector frequency & pulse duration and degree of timing retard depend
upon the engine temperature both during start-up and immediately afterwards. If the engine is restarted within one minute of the
first start occurance, less overall fuel is injected to reduce the risk of fuel flooding into the engine.
Fuel injectors
The fuel injector is a magnetically operated solenoid valve that is actuated by the ECU. Voltage to the injectors is applied from
the main relay and the earth path is completed by the ECU for a period of time (called pulse duration) of between 1.5 and 10
milliseconds. The pulse duration is very much dependant upon engine temperature, load, speed and operating conditions. When
the magnetic solenoid closes, a back EMF voltage of up to 60 volts is initiated.
The fuel injectors are mounted in the inlet stubs to the engine inlet valves so that a finely atomised fuel spray is directed onto the
back of each valve. Since the injectors are pulsed in two banks, fuel will briefly rest upon the back of a valve before being drawn
into a cylinder.
Тема: датчик идентификации цилиндра motronic 1.3 (Прочитано 12875 раз)