General System Description

Fig. 12 Electronic Concentrated Engine Control System (ECCS).:

The Electronic Concentrated Engine Control System (ECCS), incorporates Bosch L-Jetronic Fuel Injection (EFI) and employs a micro-computer within the control unit. This micro-computer controls fuel injection, spark timing, exhaust gas recirculation (EGR), idle speed, fuel pump operation, air controls, and mixture ratio feedback. The micro-computer processes incoming signal data from engine and vehicle sensors and computes signal combinations to be sent to the electrical actuators.

Control Unit:

Components

E.C.U. (E.C.C.S. control unit)
The E.C.U. consists of a microcomputer, inspection lamps and a diagnostic mode selector for signal input and output, and for power supply. The unit has control of the following functions;
- Injected fuel amount.
- Mixture ratio feedback.
- Ignition timing.
- Spark plug switching.
- Idlespeed.
- E.G.R.operation.
- A.l.V. operation.
- Fuel pressure regulator operation.
- Fuel pump operation.
- Air regulator operation.
- Self-diagnosis.

Distributor Crank Angle Sensor:

CRANK ANGLE SENSOR
The crank angle sensor is a basic component of the entire E.C.C.S. It monitors engine speed and piston position, and sends to the E.C.U. signals on which the controls of fuel injection, ignition timing and other functions are based.

Crank Angle Sensor Cut Away View:

The crank angle sensor has a rotor plate and a wave forming circuit. The rotor plate has 360 slits for 1° signal (crank angle signal) and 4 slits for 180° signal (engine speed signal). Light Emitting Diodes (L.E.D.) and Photo Diodes are built in the wave forming circuit.

Crank Angle Sensor Rotor Plate:

When the rotor plate passes the space between the L.E.D. and the Photo Diode, the slits of the rotor plate continually cut the light which is sent to the photo diode from the L.E.D. This causes generating rough-shaped pulses. They are then converted into on-off pulses by the wave forming circuit, which are sent to the E.C.U.