The camshaft is an important part of the engine air distribution mechanism. In order to ensure that the engine can work in a timely manner inhalation of fresh air, and timely discharge of the exhaust gas, the camshaft is responsible for driving the valve on and off on time, some camshaft also has the function of driving the distributor. The speed of the car engine is very high, in order to ensure the efficiency of intake and exhaust, the valve with overhead design, camshaft through the hydraulic tappet and other institutions to drive the valve action.
Although the speed of the camshaft is half the speed of the crankshaft in a four-stroke engine, its speed is still high and requires a lot of torque, so the requirements for the strength and reliability of the camshaft are high. The main body of the camshaft is a cylinder with the same length as the cylinder block. There are a number of cams. The material of the camshaft is usually special cast iron, sometimes made of forged steel and alloy. Most of the interior of the camshaft is made into a hollow structure, which not only reduces the quality of the camshaft, but also increases the ability of the cam bearing to be loaded. The camshaft is also machined with a lubricating oil passage, which is lubricated by components such as camshafts, rocker shafts, and rocker arms.
Camshaft position sensor is also called synchronous signal sensor, it is a cylinder identification positioning device, input to the ECU camshaft position signal, is the ignition control of the master signal.
The camshaft position sensor acquires the position signal of the valve camshaft and inputs the ECU so that the ECU recognizes the cylinder 1 to compress the top dead center, thereby performing sequential injection control, ignition timing control and deflagration control. In addition, the camshaft position signal is also used to identify the first ignition timing when the engine is started. Because the camshaft position sensor can recognize which cylinder piston is about to reach the top dead center, it is also known as the cylinder identification sensor.
The engine computer controls the four cylinders according to the camshaft position signal and the crankshaft position signal in the order of 1-3-4-2.
When the engine computer can not receive the camshaft position signal, according to the simultaneous injection of 1,4 cylinder, 2,3 cylinder jet injection control the way. Because the ignition coil to produce double spark, so the engine can still start and run, then deflagration control off, ignition advance angle delayed, the output power down.