Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
80
3) Test analysis
Wiring terminals: 1 - +5V, 2 – Signal +, 3 – Grounding
3. Turbocharger pressure sensor
1) Overview
The turbocharger pressure sensor is connected to the
intake pipe and is functioned to measure the absolute
pressure of the intake pipe. This sensor is composed of
one pressure unit with two sensing units and one
evaluation circuit chamber. The sensing units and
evaluation circuit are mounted on common ceramic
substrate. Each sensing unit incorporates one horn-shaped
diaphragm embodying the benchmark capacity for
determination of internal pressure. The diaphragm moves
towards large or small open extent as a function of
charging pressure. The pressure sensitive resistor is
mounted on the diaphragm surface, of which the resistance
varies under the application of pressure. These resistors are
connected to form a resistor bridge. Therefore, any
movement of the diaphragm will change the balance of
resistor bridge, namely the voltage of the resistor bridge is
one measurement of turbocharger pressure. The evaluation
circuit is functioned to amplify the bridge voltage and
compensate the linear variation of temperature influence
and pressure characteristic. The output signal of evaluation
circuit is transmitted to ECU and then the turbocharger
pressure is obtained by means of the programming
characteristic curve.
z The temperature sensor incorporates one negative
temperature coefficient (NTC) thermistor that is
connected in the voltage division circuit of 5V power
supply.
z The voltage drop on the resistor is inputted to the ECU via one analog and one digital converters (ADC), which
is one measurement for evaluating the temperature. The ECU micro-processor embodies one characteristic curve,
which defines the temperature as a function of given voltage.
z It’s installed on the pressure stabilizing chamber of intake manifold and take the priority to measure the pressure.
z Wiring terminals: 1 – Grounding, 2 – Temperature signal, 3 – +5V, 4 – Pressure signal.
2) Working Principle
The turbocharger pressure sensor is connected in the intake pipe and is capable of measuring the absolute pressure of
intake pipe at 0.5~3bar. This sensor is composed of one pressure unit with two sensing units and one evaluation circuit
chamber. The sensing units and evaluation circuit are mounted on common ceramic substrate. Each sensing unit
incorporates one horn-shaped diaphragm embodying the benchmark capacity for determination of internal pressure.
The diaphragm moves towards large or small open extent as a function of charging pressure. The pressure sensitive
Pressure
difference
sensor
5V power supply
Pressure difference signal
Earthing
To Next Page
Loading...