Luke Garratt, UK and Nordics Technical Services Manager at Delphi, observed: “Ignition coils today deliver the high electrical loads of starting cycles far more frequently due to Stop/Start and hybrid engines.” He continued: “These must produce up to 45,000 volts for efficient combustion and are expected to operate in larger temperature swings, with more high-load start cycles, increased performance expectations, and weight reductions. Short urban journeys can extend gaps and increase starting cycles further. Ignition coils still need to reliably deliver a strong spark, at the right time, to the right cylinder thousands of times per minute.” He added: “Multispark ignition coils have recently been developed by Delphi and will soon be made available to the aftermarket. They fire multiple sparks rather than a single spark on each cycle to burn fuel more efficiently.” Meanwhile, Delphi’s Masters of Motion hub includes videos on ignition coil replacement and ignition coil testing. For more information, visit: www.delphiautoparts.com/productstechnologies/vehicle-electronics-enginemanagement/ignition/ignition-coils Key role Matthew Smart, Head of Electronics at HELLA, said: “Ignition coils play a key role in the ignition system by transmitting high voltage to spark plugs, ultimately igniting the air-fuel mixture. Subjected to all the elements of the road, they also face high electrical, mechanical, thermal, and chemical stress. Alongside the iron core, there are three main components to an ignition coil; The primary winding, the secondary winding, and the electrical connections. “The magnitude of the induced high voltage relies on the rate of change in the magnetic field, the number of windings on the secondary coil, and the intensity of the magnetic field. The initial induction voltage of the primary winding typically falls between 300 and 400 V. The high voltage output of the secondary coil can reach up to 40 kV, depending on the specific ignition coil.” Matthew added: “Insufficient output voltage or energy will cause misfiring and incomplete fuel combustion in the cylinder, which can increase the vehicle’s fuel consumption, exhaust emissions and potentially, damage the catalytic converter.” For more information, visit: www.hella.com/techworld/uk/Car-parts/Autoelectrics/Ignition-coils-47430/ Warning signs Commenting on the potential causes of ignition coil failure, Fatiha Laauich, Pan European Strategic Marketing Manager at DENSO Europe said: “Although complete ignition coil 40 AFTERMARKET MARCH 2024 IGNITION www.aftermarketonline.net failure will mean the system will not be able to generate the spark required to ignite the air/fuel mixture in the combustion chamber, there are often warning signs that become apparent that potential problems exist, which owners need a qualified professional to investigate, before they suffer a breakdown. “If an ignition coil is identified as defective, to avoid a replacement also failing, it’s worth exploring the reasons why it might fail, as this can help technicians, as they diagnose the system, to correctly identify where the fault arises. However, the vehicle manufacturer’s ignition system instructions should always be the first point of reference. “The reasons for ignition coil failure can be summarised under four main headings; Internal short circuits, mechanical damage, contact failure and faults in the voltage supply. Internal short circuits can be caused by voltage overload due to a damaged or worn spark plug, an ECU control unit malfunction, general wear and tear resulting in a reduction of coil insulation, or excessive heat and abnormal engine vibration. When it comes to mechanical damage, this usually arises from an oil leakage from the valve cover gasket that degrades the insulation, but is sometimes from rodent bites from unwelcome residents! Contact failures are generally caused by water intrusion in spark plug recesses and voltage supply problems by a weak or failing battery, or faulty wiring. Fatiha added: “These factors further highlight the importance for technicians undertaking a repair to correctly identify the root cause of the issue, rather than simply replacing the first component in the process.” For more information, visit: www.densoam.eu/products/ignition/ignitioncoil#cataloguesAndLeaflets Common issues Looking towards solving ignition system issues, Autoelectro is urging mechanics to avoid trying to fix problems on cars by opting for parts swapping, and instead to work towards identifying the root cause of the issue. Autoelectro’s Harnek Bhogal said: “Blindly swapping parts without addressing the true problem could lead to an erosion of trust between garages and factors. This approach, addressing symptoms rather than causes, can lead to recurring issues and fails to provide a sustainable solution. It’s a short-term fix, not a long-term solution. Our HIGHER LOADS: BIGGER SWINGS Ignition systems are under more strain than ever before Above: Ignition coils are being put under higher demand than ever before
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