Dongfeng LoongGine Engine parts Ignition coil assembly 3705020-E9C00

As a key component of the engine’s ignition system, this assembly’s core function is to convert the vehicle’s low-voltage electrical energy (12V DC) into high-voltage energy (15-30 kV) required to ignite the air-fuel mixture in the combustion chamber. It operates based on the electromagnetic induction principle:

The assembly consists of a primary coil (with hundreds of turns of thick copper wire) and a secondary coil (with thousands of turns of thin copper wire), wrapped around a soft iron core.

When the engine ECU sends a trigger signal, the primary coil’s current is rapidly cut off, creating a strong changing magnetic field around the iron core.

This magnetic field change induces a high-voltage current in the secondary coil, which is transmitted to the spark plug via the integrated high-voltage terminal. The spark plug then generates an electric spark to ignite the air-fuel mixture, enabling engine combustion.

This process ensures stable ignition timing and sufficient spark energy, directly affecting engine power output, fuel efficiency, and emission levels

Designed to meet the rigorous demands of gasoline engine operation, the ignition coil assembly boasts excellent performance and stability:

Voltage Output: Delivers a stable high voltage of 18-25 kV (peak value) under normal operating conditions—sufficient to overcome the air gap resistance of the spark plug (typically 0.6-1.1 mm) and ensure reliable ignition even in high-altitude or high-humidity environments.

Energy Storage: Has an energy storage capacity of 40-60 mJ, ensuring the spark has enough duration (0.8-1.2 ms) to fully ignite the air-fuel mixture, reducing incomplete combustion and hydrocarbon emissions.

Operating Temperature Range: Maintains stable performance from -40℃ to 125℃—covering extreme cold (e.g., winter in northern regions) and high-temperature conditions (e.g., engine compartment heat during prolonged high-speed driving).

Electrical Efficiency: Converts low voltage to high voltage with an efficiency of ≥85%, minimizing energy loss and reducing the load on the vehicle’s alternator

The assembly features a robust structural design and multi-layer protection to withstand harsh engine environments:

Coil Housing: The outer housing is made of high-temperature resistant engineering plastic (PA66+GF30)—a material with excellent heat resistance (continuous use temperature up to 150℃) and impact resistance, protecting the internal coils from vibration, oil, and chemical corrosion.

High-Voltage Terminal: The terminal connecting to the spark plug is made of brass with a nickel plating (thickness: 5-10 μm), ensuring low electrical resistance and anti-corrosion performance. It is also equipped with a silicone rubber boot to prevent high-voltage leakage and water ingress.

Electrical Connector: The connector adopts a IP67 waterproof and dustproof design, with a rubber sealing ring and snap-in locking structure. This prevents water, dust, or engine oil from entering the connector, avoiding short circuits or signal interference.

Heat Dissipation Design: The housing features integrated heat dissipation ribs (distributed around the coil area) to accelerate heat transfer, preventing overheating of the coils during long-term operation and extending the assembly’s service life

The ignition coil assembly is widely applied in Dongfeng LoongGine-powered gasoline vehicles, including:

Dongfeng passenger vehicles (sedans, SUVs) for daily commuting and family use—requiring stable ignition for smooth driving and low fuel consumption;

Light commercial vehicles (minivans, pickup trucks) for urban logistics and short-distance transportation—operating under frequent start-stop cycles and varying load conditions;

Special-purpose vehicles (e.g., refrigerated delivery vans) that demand reliable ignition to ensure continuous operation of auxiliary systems.

In terms of installation, it offers significant advantages:

Direct OEM Replacement: Matches the original ignition coil’s dimensions, mounting points, and connector type—no modifications to the engine or wiring harness are needed. Installation only requires removing the old coil (via 1-2 mounting bolts) and plugging in the new assembly, which can be completed with standard tools in 15-20 minutes per cylinder.

Pre-Installed Components: The assembly comes with a pre-fitted high-voltage silicone boot and mounting hardware, eliminating the need to purchase separate parts and reducing the risk of compatibility issues.

Long-Term Reliability: Under normal use (with regular spark plug replacement), the assembly has a service life of over 60,000 km, reducing the frequency of ignition system maintenance and lowering overall vehicle operating costs