The Functions of CKP and CMP in Cars and How They Work, Let's Take a Look!
Knowing the functions of the CKP and CMP sensors in cars along with how they work is essential. The CKP and CMP sensors play an important role in the continuity of the EFI system in cars. So what are the functions of these sensors? To avoid misunderstanding, let’s take a look at the following review.
What is CKP? What are its Functions?
CKP is an acronym for crankshaft position. This component is only found in cars with a non-carburetor or injection system. Generally, the CKP sensor is located on the right side of the engine, at the back, or at the front of the engine. At a glance, the CKP sensor looks similar to the CMP sensor. However, the CKP sensor appears to be sturdier and harder. The CKP sensor has several functions as follows.
1. Detection Function (sensing)
The main function of the CKP sensor is actually for sensing or detecting engine rotation and piston top rotation. The signals generated from the CKP sensor are then used by the ECU to determine engine speed. Furthermore, the CKP sensor will optimize ignition and fuel injection performance.
2. Adjusting Engine Speed
Next, the CKP sensor functions to adjust the engine speed to always be ideal.
3. Reading Crankshaft Position and Angle
The CKP sensor also has the function of reading the position and angle of the crankshaft. The data read will later be used by the ECU to determine whether the piston is at TDC (Top Dead Center) or BDC (Bottom Dead Center).
4. Determining Ignition and Injection Timing
The CKP sensor also has another function, which is to determine the timing of ignition and injection. This function will operate when the ECU has received data from the CKP.
What is CMP? What are its Functions?
CMP is an acronym for camshaft. The CMP sensor itself is located at the distributor in the early release of EFI cars. Meanwhile, in modern EFI cars, the CMP sensor is located behind the CKP sensor. The functions of the CMP sensor are as follows.
1. Reading Camshaft Position
The main function of the CMP sensor is to accurately read the position of the camshaft with the help of the CKP sensor. Thus, the CMP sensor can determine the cylinder position at TDC (Top Dead Center) accurately. This information will then be forwarded to the ECU to determine when to open and close the intake and exhaust valves.
2. Determining Ignition and Fuel Injection Timing
In addition, the CMP sensor functions to determine the best timing for ignition and fuel injection in all engine combustion chambers in a structured manner.
How CKP and CMP Sensors Work in Cars
The operation of the CKP sensor is divided into two types, namely hall effect and induction. In the hall effect type sensor, the sensor does not rely on permanent magnets in its working mechanism, so changes in the magnetic field do not affect the performance of this type of sensor. The hall effect sensor only relies on a voltage of 5 V to operate. Meanwhile, for the induction type, the CKP sensor can generate low AC voltage (approximately 1 to 2 V) alternately.
As for the operation of the CMP sensor, it is also divided into two based on sensor type. In the inductive sensor, an induction coil with a resistance of 200-2500 ohms is embedded, allowing it to generate a voltage of 1-2 V. Meanwhile, in the hall effect sensor, the CMP sensor requires a higher voltage of 5-12 V.
Considering the crucial functions of the CKP and CMP sensors in the ignition and fuel injection processes, it is advisable to always check the condition of these sensors, and if there are any issues, immediately service the sensors at the nearest Daihatsu workshop.
