A knock sensor mounted on an engine block in the middle on the four-cylinder machine, for example mounted between the cylinder 2 and the cylinder 3, or 1, a middle cylinder 2, a middle cylinder 3,4. The engine is used to determine the degree of jitter, when the engine is used to knock the ignition advance angle. The piezoceramic usually, when the engine jitter which is pressed to produce a ceramic electrical signal, the electrical signal is weak because it is connected to the general line of the knock sensor are wire wrapped shield.
knock sensor signal generator is AC, but they are most other automotive AC generator differ, as in addition to the speed of magnetic crankshaft and camshaft position sensors detect the same position and the shaft, which also detect vibration or mechanical stress. The stator and the magnetoresistors different, they are usually a piezoelectric device. They can sense vibrations or mechanical stress (e.g. to produce an AC voltage when starting the engine knock) of special material.
premature ignition, exhaust gas recirculation poor, low-grade fuel and other causes engine knock can cause engine damage. Knock sensor providing a knock signal to a computer (via some mold tactics control point), so that the computer can re-adjust the ignition timing to prevent further knocking. They are in fact act as an ignition timing feedback control loop “oxygen sensor” role.
The knock sensor placed in different positions of the engine block or cylinder. When vibration or knocking occurs, it generates a small voltage peak, the larger the vibration or knock. The main peak of the knock sensor producing greater. Indicates that certain frequency is high or knock knocking, knock sensor typically designed to 5 to 15 kHz frequency range measured. When the control unit receives these frequencies, the computer re-correcting the ignition timing to prevent knocking continues, a knock sensor is generally very durable. Therefore, the sensor will be damaged because of their failure.
the pressure wave generated when an engine knock, a frequency of 1-10 KHz. Cylinder pressure wave to pass, so that the metal particle vibration acceleration. Knock sensor is an accelerometer by measuring acceleration of the vibration of the cylinder surface detecting a knock intensity of the pressure. is a major cause of premature ignition timing knocking Since the maximum power requirements of the engine can be issued, in order not to loss of engine power while knocking does not occur, the installation of the knock sensor, electronic control means for automatically adjusting the electrical ignition timing.