Working Principle and Types of Throttle Position Sensor

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I. Working Principle of Throttle Position Sensor

The principle of the throttle position sensor is actually a sliding varistor. When the throttle is pressed, the idle signal line is disconnected, the sliding varistor also follows the rotation, the computer detects the voltage value, the data obtained by comparison, analysis, and control basic Injective amount.

The throttle angle position sensor has two variable resistance, responsible for feedback to the system.

One of the electrical throttle resistances increased linearly, and the electrical throttle resistance value of the electronic throttle is decreased. The resulting voltage signal (position information of the throttle) is conveyed to the engine control unit to reflect the change of the throttle opening and the opening rate of the opening rate and is used to process information and control the throttle, which can feed back the position information of a throttle. The control unit forms a closed-loop control. Thus, when the control unit passes the instruction to the adjustment motor. The motor can correctly turn the throttle valve to rotate the throttle valve according to the information feedback of the sensor. Two sensors are for accurate and standby.

The throttle position sensor enters failure protection

1) When a sensor is reported, another sensor signal is used. The response to the accelerator pedal is unchanged, but there will be accelerated weakness, cruise system shutdown. EPC fault light is on, store the fault code.

2) When two signals are interrupted. The engine runs around 1500r / min. Stepping on the accelerator pedal without reaction, the EPC fault light is on, and there is a fault code storage.

Caution: The throttle position sensor, the idle air valve, and the throttle body are integrated structures. When the throttle position sensor or idle control valve fails. The throttle assembly should be replaced.

The throttle position sensor is also known as a throttle opening sensor or a throttle switch. Its main function is to detect the engine is in an idle condition or a load condition. It is an acceleration and reduction. It is essentially a variable resistor and several switches, mounted on the throttle, there are two contacts: full open contacts and idle contacts. When the throttle is in an idle position, the idle contact is closed, and the idle operating condition signal is output to the computer; when the throttle is in other locations, the idle contact is opened, the output is output relative to the voltage signal of different corners of the throttle, according to the signal The voltage value recognizes the load of the engine; the change in the change in increase in the signal voltage in a certain period of time is an acceleration operating condition or a deceleration. The computer corrects the amount of fuel according to this operating information or performs oil-oil control.

II. Types of Throttle Position Sensor

Traditional position sensors can be classified into sliding resistance position sensor, idle switching position sensor, and sliding resistance integration position sensor. The throttle position sensors used in the new intelligent electronic throttle shaft door control system are a double slide resistance sensors and linear double Hall sensors.

At present, the engine electrical control system mainly adopted the throttle position sensor with Hall components sensor and double slide resistance sensor. Toyota Camry, Carolla, etc. use Hall sensor; Nissan Scorpio, General Excelle use double slide resistance sensor.

1. Hall Throttle Position Sensor

2016 Toyota Camry Mixed Power Model (Engine Model 6Ar-FSE) uses a non-contact Double Hall element throttle position sensor. It is mainly composed of Hall elements and magnets, with magnets being mounted on the throttle axis and can be rotated around the Hall element.

The control circuit of the Hall-style throttle position sensor is shown in the figure above. When the throttle opening is changed, the magnet rotates, thereby changing the relative position between the Hall element, and the Hall integrated circuit is surrounded by the yoke. The Hall integrated circuit converts the change in the magnetic flux into an electrical signal and outputs it to the ECM in the form of the throttle position signal.

The throttle position sensor has two sensor circuits: VTA1 and VTA2, each emission a signal. VTA1 is used to detect throttle opening, and VTA2 is used to detect VTA1 failures. The sensor signal voltage is proportional to the throttle opening and is varied between 0 to 5V and transmitted to the ECM terminals VTA1 and VTA2.

When the throttle is closed, the sensor output voltage is lowered; when the throttle is opened, the sensor output voltage rises. ECM calculates the throttle opening according to these signals and controls the throttle effector to respond to the driver input. These signals are also used to calculate air-fuel ratio correction values, power lift correction values, and fuel cut control.

The throttle position sensor circuit of the 2016 Toyota Camry Mixed Power Version is shown below.

The throttle position sensor is integrated within the throttle assembly E16. E16 has 6 pins. Pins 1 and 2 For the throttle, the motor control port is performed. Pins 6 and 4 leave the output throttle position signal VTA1 and VTA2 to 122 # and 88 # of the engine control unit port E81 (f). Pin 5 is a VCTA 5V reference voltage supplied from the engine control unit 121; pin 3 is grounded through the engine control unit 120 #.

Testing

(1) Check the sensor power supply: Disconnect the throttle connector E16, measure the voltage between E16 / 5 and E16 / 3 with a multimeter, which should be 4.5 to 5.5V. Otherwise, check the ECU power circuit. If the ECU power circuit is normally, the ECU is replaced.

(2) Check the signal voltage of the sensor: Connect the fault diagnostic, turn on the ignition switch, step on the accelerator pedal, and read the throttle position sensor data VTA1 and VTA2 reading.

Check the sensor harness and connector: Disconnect the throttle connector E16 and the engine control unit ECM connector E81, and check the resistance between the plug or the ground between the connector and the body.

2. Slide Resistance Throttle Position Sensor

Slide resistance throttle position sensor, also known as linear output throttle position sensor, variable resistive throttle position sensor, potential ribbon throttle position sensor. At present, the dual variable resistance throttle position sensor is being applied to a large number of vehicles.

The sliding resistance throttle position sensor is a three-wire sensor, wherein the two pins are at both ends of the resistor and serve as the power terminal and the iron terminals by the engine ECU, and the third pin is connected to the sliding contact. The throttle shaft is linked to the contact (or contact). When the throttle is rotated, the sliding contact can move on the resistor, causing a change in the sliding contact potential to convert the throttle position signal to a voltage value. Since this voltage is linear, it is also known as a linear output throttle position sensor. According to this linear voltage value, the ECU can sense the opening degree of the throttle to correct the ECU.

Testing

The throttle position sensor circuit of the 2013 Buick Excelle is shown below. The engine control module provides a 5V reference voltage circuit to the throttle position sensor and provides a grounding of the low reference voltage circuit. The signal voltage provided by the throttle position sensor changes with the throttle opening. The throttle position sensor signal voltage is less than 0.5V at idle operation. The throttle position sensor voltage is generally close to 0V at idle speed but maybe as high as 0.5V. In the throttle full open (WOT), the valve position sensor voltage should be increased to 4V.

The throttle position sensor is tested as follows:

(1) Turn off the ignition switch and disconnect the wire harness connector on the throttle assembly.

(2) Measure the resistance between the throttle position sensor 5V reference terminal 2 # and the low-pressure reference terminal 1 # is 5.0 to 5.3 kΩ. If the resistor is not within the specified range, replace the throttle assembly.

(3) Measure the resistance between the throttle assembler signal terminal 3 # and the low-pressure reference terminal 1 #. The throttle sensor is detected in full range. The electrical resistance should be transformed between 2.5 to 6.8kΩ, without any peak or trough. If the resistor is not within the specified range or does not change, replace the throttle assembly.

(4) Use 5V voltage and grounding the applicable end terminal of the throttle sensor to detect the voltage between the signal terminal and the low-pressure reference terminal. The throttle sensor is detected in full range. The voltage should be transformed between 0.6 to 4.7V, without any peak or trough. If the voltage is not within the specified or not, replace the throttle assembly.