Design Features

The engine fitted to cars Chevrolet Lanos, equipped with electronic engine management with fuel injection. This system ensures that the current standards for toxic emissions and vapors while maintaining high ride quality and low fuel consumption.

Managing devices in the system is an electronic control unit (ECU). On the basis of information received from the sensors, the computer calculates the fuel injection control and ignition timing control. In addition, in accordance with the incorporated algorithm ECU controls the operation of the motor cooling fan motor and electromagnetic clutch of the compressor air conditioner performs a self-diagnosis function elements of the system and alert the driver of any fault.

When failure of individual sensors and actuators control unit includes emergency operation to ensure efficiency of the engine.

The amount of fuel supplied to the injectors is determined by the duration of the electric signal from the ECU. The electronic unit monitors the data on the state of the engine, expects demand for fuel and determines the required duration of the fuel supply nozzle (signal duration). To increase the fuel supply quantity signal duration increases to decrease the fuel supply - is reduced.

The engine management system, along with an electronic control unit includes sensors, actuators, connectors and fuses.

The electronic control unit (ECU) connected by electrical wires to all of the sensors. Getting information from them, the unit performs calculations in accordance with the parameters and the control algorithm stored in the memory of a programmable read-only memory (PROM), and controls the actuators of the system. Option program recorded in the memory PROM, identified by a number assigned to this modification of the ECU.

The control unit detects the fault, identifies and memorises the code, even if a failure is unstable and disappear (e.g., because of poor contact). Warning light engine management system in the instrument cluster goes out 10 seconds after the restore functionality of the failed node.

After the repair is stored in the control unit to erase fault code. To do this, turn off the power to the unit 10 (remove the supply fuse the electronic control unit or disconnect a wire from the plug "minus" of the storage battery).

The unit is powered by direct current voltage of 5 and 12 in the various sensors and switches control system. Since the electrical resistance of a circuit is high, the test lamp connected to a system, does not light up. To determine the voltage across the terminals of the ECU should be used voltmeter with an internal resistance of at least 10 MW.

ECU is not suitable for repair in the event of failure it must be replaced.

Diagnostic connector is used to output from the computer memory fault codes identified in the engine management system. Marking and pin diagnostic connector shown in Fig. 10.6.

Pin assignment:

A - "mass";

B - diagnostic output;

E - output "plus".

The diagnostic connector is located inside the vehicle in the footwell of the driver on the right side under the dashboard. Self-test mode is activated when connecting the output of the "B" (diagnostic output) with the conclusion "A" connected to "weight", and turn on the ignition (the engine must not be running). The diagnostic socket, you can connect a scanning device that reads information from the serial data line.

The coolant temperature sensor is installed in the engine cooling system. The sensing element is a thermistor whose electrical resistance varies inversely with temperature. At low coolant temperature (-40 ?� C), the thermistor resistance is about 100 ohms, with increasing temperature up to +130 ?� C - is reduced to 70 ohms.

Electronic unit temperature sensor circuit feeds a constant reference voltage. The voltage sensor as possible the engine is cold, and decreases as it is warm. As the value of voltage electronic control unit detects the temperature of the engine and allows it in the calculation of the adjustment parameters of injection and ignition. When the sensor fails or irregularities in the chain connecting his computer sets a fault code and stores it. For troubleshooting, check the reliability of contact connections in the wiring to the sensor or replace the sensor.

Sensor Intake Air Temperature (glued into the air supply hose) similar in design to the coolant temperature sensor, it is also used thermistor changes its resistance depending on the temperature.

Thermistor resistance is 100 ohm at a temperature of -40 ?� C and increasing the temperature to +130 ?� C is reduced to 70 ohms.

ECU feeds the sensor circuit constant reference voltage. Sensor signal voltage is maximum, when the air in the intake pipe is cold, and decreases with increasing temperature. As the value of the voltage control unit determines the intake air temperature and makes adjustments in the calculation of the ignition timing. When the sensor fails or irregularities in the chain connecting his computer sets a fault code and stores it. If the computer continues to give the fault code when serviceable contact connections in the wiring, replace the air temperature sensor.

The crankshaft position sensor inductive type for synchronization of the electronic control unit with piston TDC 1st and 4th cylinders and the angular position of the crankshaft.

The sensor is installed in front of the engine in front of the master disc on the crankshaft pulley. The master disc is a toothed wheel with equidistant depressions. Two teeth are cut to a pulse synchronization ("reference" pulse), which is required to coordinate the work of the control unit with the TDC of the pistons in the 1st and 4th cylinders.

When you rotate the crankshaft teeth alter the magnetic field sensor, inducing voltage pulses of alternating current. The control unit of the sensor signals determines the frequency of rotation of the crankshaft and sends pulses to the injectors.

When the sensor fails motor starter.

The throttle position sensor installed on the side of the throttle unit and is connected to the throttle valve axis.

The sensor is a potentiometer one end of which is supplied the "plus" voltage (5 V) and the other end connected to the "weight".

From the third output potentiometer (slider) is the output signal to the electronic control unit.

When the throttle is rotated (on the impact on the foot pedal), change the output voltage of the sensor. At closed throttle is less than 0.5 V. When the valve opens, the voltage at the output of the sensor increases at full throttle, it should be more than 4 V.

Tracking the sensor output voltage, the controller adjusts the fuel flow depending on the throttle opening (i.e., driver's demand).

Throttle position sensor requires no adjustment as the control unit receives the idle speed (ie the complete closure of the throttle) as the zero point.

The gauge of absolute pressure in the inlet pipe converts the vacuum in the pipe in the voltage at which the value of the electronic control unit determines the engine load. The sensor is installed in the engine compartment, mounted on the partition bulkhead and is connected to the inlet pipe by a rubber tube. The sensor output voltage varies in accordance with the pressure in the intake pipe - 4.9 V (at full throttle) to 0.3 V (when the valve is closed). At the idle engine control unit voltage sensor detects atmospheric pressure and adapts the control parameters to the specific injection altitude. Atmospheric pressure value stored in the memory, periodically updated with a uniform movement of the car, and during full throttle.

Vehicle speed sensor is mounted on the gearbox. The operating principle of the sensor is based on the Hall effect. The sensor outputs to the electronic control unit rectangular voltage pulses with a frequency proportional to the rotational speed of the drive wheels.

The gauge of concentration of oxygen (lambda probe) is screwed into the threaded hole of the exhaust manifold. The metal flask sensor is a galvanic cell, washed by the flow of exhaust gases. Depending on the oxygen content in exhaust gases from the combustion of air-fuel ratio sensor varies the signal voltage.

Information from the sensor is supplied to the control unit in the form of signals of low (0.1 V) and high (0.9 V) level. At low signal level control unit receives information on the high oxygen content and therefore on a lean mixture. A high level signal indicating a low oxygen content in the exhaust gases and therefore of pereobogaschenie mixture.

Continuously monitoring the voltage sensor signal, the control unit corrects the amount of injected fuel injectors. At a low level sensor (lean air-fuel mixture) fuel flow is increased at a high level signal (rich mixture) - decreases.