Geo Knock Sensor

Geo knock sensor is just one of the standard sensors found in Geo vehicles that monitor the different automobile parameters. A knock sensor is a small piezoelectric microphone embedded on the engine block to detect the characteristic frequency of engine knocking or fuel detonation. It is connected to the electronic control unit or ECU of the engine. When engine knocking is detected the knock sensor sends electrical signal to the ECU. In turn, the ECU makes appropriate adjustment to counteract the engine knocking. Sparkplug firing is slowed down and the amount of fuel injection is reduced. Engine knocking sometimes can be audibly detected as a pinging metallic sound. During engine knocking, the pressure inside the combustion chambers increases catastrophically.

Since pressure seeks to escape, a sudden buildup of pressure may cause the gaskets to rupture. On the other hand, the pistons and crankshaft may become dislocated. The damage on this stage is seldom reversible. In extreme cases, the engine itself may explode. Under normal condition, combustion occurs as a smooth and calibrated process. Fuel/air mixture is rapidly burned at the correct timing. This allows the pistons to optimize the power stroke and return to maximum recovery. However, when fuel detonation occurs, this process is disrupted. Engine combustion itself may cease. Pressure instantaneously builds up but rapidly diminishes. The pistons are not given enough time to adjust. Hence, engine knocking becomes counterproductive.

Combustion is initiated by the sparkplug. The sparkplug discharges a high-voltage spark that ignites the fuel/air mixture. However, there are instances wherein the fuel/air mixture is prematurely ignited and explosion occurs. When this happens, the shockwave of detonation reverberates throughout the engine block. The Pressure inside the combustion chambers may be thrown out of balance. If the shockwaves are intense enough, the normal motion of the pistons and crankshaft will be disrupted. Optimal power stroke will not be reached and the pistons will not have enough time to recover to start maximum compression. Maximum compression is necessary to assure the complete combustion of the fuel.

Ironically, although engine detonation is more energetic than normal combustion, energy and engine power are wasted. Engine knocking is a detonation that is ill-timed. Instead of contributing to the overall output of the engine, it counteracts engine output. Consequently, engine output is effectively cancelled because combustion is interrupted. Although engine knocking can be prevented, an engine knock sensor is still necessary to counteract engine knocking when it occurs. A defective engine knock sensor will not send correct data to the ECU. Hence, a defective knock sensor must be replaced immediately. If you are looking for high quality knock sensor, Parts Train is the one stop online shop for aftermarjet knock sensors and other automotive supplies.

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