What is a car ignition coil
The ignition coil of a car is the core component of the car ignition system . Its main function is to convert the 12V low-voltage direct current provided by the battery into high-voltage electricity of up to 20,000 to 30,000 volts through the principle of electromagnetic induction, providing the energy needed for the spark plug to break through the air-fuel mixture, thereby igniting the fuel mixture in the engine cylinder. Its working principle is based on electromagnetic induction: when the primary coil is energized to generate a magnetic field, the ECU (Electronic Control Unit) controls the current to be cut off, and the magnetic field disappears rapidly. The secondary coil induces high voltage due to the change in magnetic flux. This process needs to be precisely completed within milliseconds to ensure the efficient and stable operation of the engine.
The reason why the ignition coil can convert the low-voltage electricity on the vehicle into high voltage is that it has the same form as a common transformer, and the turns ratio of the primary coil to the secondary coil is large. However, the working mode of the ignition coil is different from that of a common transformer. A common transformer operates continuously, while the ignition coil operates intermittently. It repeatedly stores and releases energy at different frequencies according to the different speeds of the engine.
When the primary coil is connected to the power supply, a strong magnetic field is generated around it as the current increases, and the iron core stores the magnetic field energy. When the switch device disconnects the primary coil circuit, the magnetic field of the primary coil rapidly decays, and a very high voltage will be induced in the secondary coil. The faster the magnetic field of the primary coil disappears, the greater the current at the moment of current disconnection, and the larger the turns ratio of the two coils, the higher the voltage induced by the secondary coil.
A malfunction of the ignition coil in a car can cause a series of engine abnormalities, affecting driving safety and performance. The following explains from aspects such as symptoms, causes, detection and maintenance.
Youdaoplaceholder0 Fault symptoms: The typical manifestations of ignition coil failure include:
Youdaoplaceholder0 Difficulty in starting : When starting cold, the engine only makes a "dada" sound but fails to start, or the starting time exceeds 5 seconds.
Youdaoplaceholder0 idle vibration : Regular vibrations occur in the vehicle body, steering wheel or seat during idling, with the speed fluctuation exceeding ±50rpm.
Youdaoplaceholder0 Weak acceleration and jerking : Power is interrupted in the 2000-3000 RPM range. There is a "jerking sensation" when you press the accelerator hard. Power is lost when overtaking.
Youdaoplaceholder0 cylinder misfire phenomenon : Engine cylinder misfire can cause the exhaust pipe to make a "putt-putt" sound, increase fuel consumption and accelerate the formation of carbon deposits.
Youdaoplaceholder0 Serious fault : Complete misfire in individual cylinders may prevent the engine from starting or cause the three-way catalytic converter to get clogged.
Youdaoplaceholder0 Fault cause: Common causes include:
Youdaoplaceholder0 Overheating and environmental factors : engine overheating, high-temperature environment or poor heat dissipation can cause coil erosion.
Youdaoplaceholder0 Electrical issues : excessively high power supply voltage, open circuit or short circuit to ground in high-voltage lines, ignition controller failure.
Youdaoplaceholder0 component correlation problem : Excessive carbon deposits, too large gap or short circuit on the spark plug, increasing the load on the coil.
Youdaoplaceholder0 Quality and installation defects : Poor quality of the coil itself, inter-turn short circuit, or mismatch with the vehicle model.
Youdaoplaceholder0 Improper operation : forgetting to turn off the ignition switch after parking causes the coil to overheat due to prolonged power-on.
Detection and diagnosis methods: can be screened through the following steps:
Youdaoplaceholder0 Symptom observation : Pay close attention to high-incidence symptoms such as difficulty in cold start and jerking during sudden acceleration.
Youdaoplaceholder0 Visual inspection : Open the engine compartment and check if the coils have cracks, burn marks or oil stains.
Youdaoplaceholder0 Resistance test : Use a multimeter to measure the coil resistance. The normal range for the primary coil is 0.5-2Ω, and for the secondary coil, it is 8-15kΩ.
Youdaoplaceholder0 OBD fault code reading : Fault codes such as P0300 (random cylinder misfire) or P0301-P0304 (specific cylinder misfire) can assist in locating the problem.
Youdaoplaceholder0 Professional test : The normal range for ignition energy test is 20-40kV. If it is below 15kV, the coil needs to be replaced.
Youdaoplaceholder0 Maintenance and preventive measures: Regular maintenance can extend the lifespan of the coil:
Check the appearance of the coil, the connection status and the spark plug gap every 20,000 kilometers.
When replacing the spark plugs, check the coils simultaneously as their lifespans are related.
Keep the engine compartment clean and dry, and avoid direct rinsing when washing the car.
Start the vehicle and wait for more than 30 seconds to reduce the impact of instantaneous current.
Use recommended octane gasoline (such as No. 95) to reduce carbon deposit formation.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
