Crankshaft Position Sensor: Design and Diagnostics
The position sensor is used to control the internal combustion engine. With its help, the electronic unit on the microprocessor reads information. More specifically, it determines in which position the crankshaft is located, on this basis, sees where the pistons are located at a particular point in time. This parameter is necessary for the correct operation of the injection system and gas distribution.
The main properties of KDPV
There are several names for this device, all equivalent. The most common term is “crankshaft position sensor,” or abbreviated KDP. Sometimes it is called the top dead center sensor, a bit more often - a phase or synchronization sensor. But no matter how it is called, failure leads to the fact that the engine stops and can not continue to work. The reason is that it is he who determines at what point in time it is necessary to apply a discharge to the spark plug electrodes.
In the event that the engine has stopped, it will not start, although even a rubber timing belt is intact and transmits movement to the camshaft, it is possible to judge the malfunction of the DPKV. In addition, on the dashboard, if the sensor fails, the warning lamp will illuminate, indicating any malfunction in the ACS. In order to correctly diagnose this device, it is necessary to know the principle of its operation and the device.
CKPV design and its main elements
The VAZ crankshaft position sensor has a fairly simple circuit. It contains several basic elements:
- Magnetized steel core.
- The frame of the caprone.
- A coil of thin copper wire in lacquer insulation was wound over the frame.
- All elements are filled with compound.
Set DPKV in the immediate vicinity of the crankshaft pulley, which has teeth. And all of them should be 60, but in one place two are cut out. Due to this gap, the control unit sees when the piston of the first cylinder is located at TDC.
The principle of the sensor
In the work of the CES incorporated the principle of electromagnetic induction. When the crankshaft rotates, the pulley with the teeth moves near the sensitive surface of the sensor.At the moment when the metal tooth passes near KDPV, a weak impulse starts to be generated in the winding. There are 60 such current surges per revolution (according to the number of teeth on the pulley). But there is a small gap, as mentioned earlier.
Due to the fact that there is a gap between the teeth, at a certain point the time interval between the pulses increases. The ECU sees the crankshaft starting to make the next turn. At the same time, the crankshaft position sensor 2110 counts 20 pulses. This is exactly the moment when in the first cylinder the piston is located in the highest position. Due to this, voltage is applied to the electrode of the candle.
Sensor installation location
Its location is on the side of the gas distribution mechanism. In this place there is a pulley of the generator drive, on which the teeth are applied. The sensor is located on the engine side, which is closer to the partition of the engine compartment. Not very convenient location to make a replacement, you will need to remove the right wheel. The device is connected to the on-board network using a wire, its length is 0.7 meters.
By the way, you can make a simple anti-theft system using the signal from the crankshaft position sensor.To do this, it is enough to install a simple relay with normally open contacts in the switching circuit. In the ignition key to mount a small but strong magnet, and in the lock - reed switch. Such a simple scheme will be able to protect the car from theft, since the slightest distortion or even interruption of the signal from the sensor leads to a complete stop of the engine.
Immediately it should be noted that many factors affect the operation of the sensor. Moreover, it is necessary to carefully monitor that there are no interference from high-voltage wires. If they are, then an error may appear on the dashboard, although the engine will operate normally. The presence of a warning is misleading, since no visible signs appear.
To check you need only a multimeter. The main thing is to be able to measure the resistance of the sensor winding. To do this, unplug the plug and connect a multimeter to it. The resistance value should be about 0.85-0.9 kΩ. If it deviates from this in any direction, then there is a short circuit between the turns. The signal is eventually distorted, the computer does not perceive it.Also often happens and wire breakage. As a result, there is no signal at all.
To remove the old and install a new one instead, you will need to lift the right side of the car. After that, unscrew the bolts on the wheel in order to gain access to the installation site of the CELP. In fact, the crankshaft position sensor, which is replaced only according to this scheme, can be removed without removing the wheel. True, there is no convenience. Therefore, it is better to raise the car on a jack.
Do not forget when replacing that the gap between the upper part of the pulley tooth and the sensitive surface of the sensor should be in the range of 1-1.5 millimeters. Otherwise, it will not work correctly.
This is what a crankshaft position sensor is. Its price is about 300-350 rubles. It is better to always have a spare in the glove compartment so that its breakage does not come as a surprise to you.