The Brief Introduction :There Are Several Sensors And Their Functions In The Howo Trucks Engine Electronic Control System:

(1) Air Flow Sensor

The hot film air flow sensor is mounted on the engine intake manifold to measure the air flow into the engine. The air flow sensor is actually.
Contains a combination of air temperature sensor and air pressure sensor, air flow sensor feedback information, is the ECU calculation of fuel injection.
The important basis of quantity. The four wiring terminals of the sensor connect to the four terminals of the ECU, as shown in figure 1-106. Ground cable 1 connects to A19 of the ECU, temperature signal cable 2 connects to A2 of the ECU, positive 5V power cable 3 connects to A3 of the ECU, and pressure signal cable 4(0-5 v) connects to A34 of the ECU.

(2)Flywheel (Engine) Speed Sensor

Flywheel speed sensor can also be called engine speed sensor. It is an induction sensor, and 58 signals are generated in the edge system of flywheel front end face.
Two vacant holes are available, as shown in Figure 1-107. The flywheel speed sensor head, fixed on the cylinder body, will directly feel the changes in the position of these holes. The signal of the position of the vacant hole measured by the engine flywheel at each turn is identified by the electric control unit (ECU) as the top stop of the first cylinder piston.
Baseline signal to the point swearset. This signal is used by FCU to realize the advance Angle and injection time of main injection and pre-injection, and the signal is transferred by FCU.
Change engine tachometer to show engine speed.
The two terminals of the flywheel speed sensor are connected with wires to THE ECU terminals A29 and A37. When installing, the gap between sensor induction head and flywheel is 0.8~1.5mm, and keep vertical. If the clearance and position are not correct, check and adjust sensor support 4 as shown in Figure 1-108, and tighten bolt 3.

(3) Coolant Temperature Sensor

The coolant temperature sensor is a NTC torture sensor. That is, the positive value decreases as the temperature increases. It uses NTC thermosensitive electric plate as sensing element to measure the resistance value of coolant at different temperatures, and then converts it into 0~5V voltage signal and sends it to FCU, so that FOU can work to the relevant actuator.
The instructions. The electropositive value of the coolant temperature sensor at different temperatures is as follows: the electropositive value is 48.5kq at 40℃, and the negative value is 1 at -20℃.
At 5.67kq.0 ℃, the resistance value is 5.86KQ2.50Ko at 20℃, 1.17kq at 40℃, and 0 at 60℃.
59K2, 80℃ positive value is 0.32KQ 100℃ resistance value is 0.18K ω.
The coolant temperature sensor is mounted on the thermostat seat, and the two wiring terminals of the sensor are connected with wires respectively to A1 and A30 terminals of the ECU. When the coolant temperature exceeds 98 ° C (or up to 105 ° C), the ECU electronic control center starts the electromagnetic cooling fan. The ECU also disconnects the electromagnetic clutch of the air conditioner compressor and stops the operation of the air conditioner.

(4)Cam Phase Sensor

The camshaft position sensor is also an inductive sensor. The two wire terminals of the sensor are connected with the two terminals A4 and A31 of the ECU by wire.
It is used by ECU to determine the end point of the live cold compression stroke of each cylinder of the engine (the inlet and exhaust valves are closed at the same time), and it is an important reference point to determine the injection timing of electronic injector (pre-injection and main injection). The camshaft position sensor is mounted on the cylinder cover and the sensor head is aligned with the camshaft drive gear.
The timing information of prejet and main jet can be obtained by the ECU after two adjacent boss and vacancy on the inner edge of. The air clearance of the sensor head ranges from 0.8 mm to 15mm. Adjust the position of support 4 as shown in figure 1-109. Camshaft position sensor at 20℃, its normal negative value is 860Ω.

(5)Fuel Temperature Sensor

The fuel temperature sensor contains a fuel clog sensor, also of NTC type, assembled on a fuel filter assembly and connected with wires to terminals A15 and A30 of the ECU. When the fuel temperature exceeds 70℃, the ECU will reduce the injection pressure; Engine power is reduced to 60% when fuel temperature exceeds 90 ° C.

(6)Clutch Pedal Sensor And Brake Pedal Sensor

Respectively mounted on the clutch pedal and brake pedal bracket, the structure and principle are the same, the conventional state is closed circuit, step down state is cut off electricity
Lk. When the pedal is pressed down, the ECU cuts off the signal by circuitry, rapidly reducing the amount of fuel injected into the electronic injector: the brake pedal also lights up the rear brake lamp.

(7) Fuel Pressure Sensor

The fuel pressure sensor is mounted on the common rail accumulator to provide common rail fuel pressure information. It has semiconductor pressure sensitive strain limited type bridge electricity inside.
It can convert the received fuel pressure signal into electrical signal, and output 0.5~4.5V voltage signal to ECU electric control sheet after calculation and amplification.
This will control the fuel pressure regulator to correct the fuel pressure to the appropriate level.
The fuel pressure sensor is connected to terminals A6, A14 and A33 of THE ECU by three wires respectively.

(8) Accelerator Pedal Position Sensor

Accelerator pedal position sensor is composed of position sensor and speed switch, which is a special part for accelerator pedal. The position sensor is a sliding potentiometer, which feedback to the ECU at any time when the accelerator pedal throttle opening voltage signal, the input voltage is 5V, throttle resistance value is 1kQ.
When the accelerator pedal is completely released and the ignition switch is turned off, the ECU receives a signal to immediately cut off the fuel supply to the electronic injector. When the engine.
Idle switch on a point before reaching the lowest speed can maintain the stable operation of the engine. Accelerator pedal position sensor with wire and ECU respectively.
The B2, B13, B27, B35 terminals are connected.

(9) Atmospheric Pressure Sensor

The atmospheric pressure sensor is located inside the ECU, which can measure the atmospheric pressure at different altitudes and convert it into electrical signals for the ECU to correct the amount of fuel injection at non-return altitudes.

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