Electrical engineering

“Knocking” occurs when the air-fuel mixture self-ignites prematurely. Sustained knocking causes damage primarily to the cylinder head gasket and cylinder head. The knock sensor identifies the high-frequency engine vibrations characteristic of knocking and transmits a signal to the ECU. The aim is to obtain the maximum energy yield by starting ignition as early as possible. Engines with a knock sensor can reduce fuel consumption and increase torque. What is knock sensor? The knock sensor monitors the combustion process in the engine. Its signal helps the engine control to prevent knocking combustion and therefore protect the motor/engine control. On this page we will provide you with various information, including how a defective knock sensor becomes noticeable, the causes that may lead to its failure, and how it can be tested in the workshop. Important safety note The following technical information and practical tips have been compiled by HELLA in order to provide profess...

A wheel speed sensor (WSS) or vehicle speed sensor (VSS) is a type of tachometer. It is a sender device used for reading the speed of a vehicle's wheel rotation. It usually consists of a toothed ring and pickup. Purpose The wheel speed sensor was initially used to replace the mechanical linkage from the wheels to the speedometer, eliminating cable breakage and simplifying the gauge construction by eliminating moving parts. These sensors also produce data that allows automated driving aids like ABS to function. Construction The most common wheel speed sensor system consists of a ferromagnetic toothed reluctor ring (tone wheel) and a sensor (which can be passive or active). The tone wheel is typically made of steel and may be an open-air design, or sealed (as in the case of unitized bearing assemblies). The number of teeth is chosen as a trade-off between low-speed sensing/accuracy and high-speed sensing/cost. Greater numbers of teeth will require more machining operation...

 The camshaft sensor enables the engine control to determine the exact position of the crankshaft drive. This information is required to calculate the ignition point and injection point, among other things. On this page, you can find out how a fault on the camshaft sensor can manifest itself, and which steps should be taken during troubleshooting. 1. CAMSHAFT SENSOR FUNCTION:  FUNCTIONAL      PRINCIPLE The task of the camshaft sensor is to work with the crankshaft sensor to define the exact position of the crankshaft drive. Through the combination of both sensor signals, the engine control unit knows when the first cylinder is in the top dead point.  This information is needed for three purposes: (1)For the start of injection during sequential injection. (2)For the actuation signal of the solenoid valve for the pump-nozzle injection system. (3)For cylinder-selective knocking control.  The camshaft sensor works according to the Hall principl...

A growing focus on reducing CO2 emissions means that mass airflow sensors are becoming increasingly important in ensuring the optimum air fuel ratio. Mass airflow sensors are positioned directly after the air filter in the intake manifold and supply information on temperature, humidity and intake air volume. Despite their highly compact construction they feature precision technology to capture information, which – together with other engine data – enables optimum engine management. This data includes: Intake air temperature Intake air humidity Intake air volume In gasoline engines, mass airflow measurement is used in conjunction with other sensor readings to regulate the supply of fuel to the engine. In diesel engines, mass airflow sensors are used to regulate the exhaust gas recirculation rate and calculate the maximum injection quantity. Our mass airflow sensors are exceptionally reliable and highly capable of withstanding environmental factors. Their dynamic measurement ...