1994-03-01

Performance Improvement from Dual Energy Ignition on a Methanol Injected Cosworth Engine 940150

Based on testing done on a 4-cylinder Cosworth dual overhead cam engine, running on methanol, a significant performance improvement was achieved with a Dual Energy Distributor-Less Ignition system. Peak power was increased by 2%, with an over-all average power increase of 3% over the entire power curve. Peak torque was increased by 4% and, most significantly, MBT timing advance was decreased by 7 degrees. The system was tested with one ignition coil per cylinder, discharging 2 Joules of energy/firing to 7,200 RPM.
The Dual Energy ignition system delivers energy to the spark plug more efficiently by separating the voltage creation device from the current delivery device. This separation improves the impedance matching of the circuit during the SPARK and the ARC modes that occur during the ignition process. It is very simple to implement with the addition of two low-cost components to each ignition coil. The system does, however, require one shielded coil per cylinder to meet Federal requirements for electromagnetic interference.
The Dual Energy Ignition provides the benefit of allowing the engine control system to significantly vary the energy delivered to the spark plug. During cold starts energy delivered can be increased to reduce hydrocarbon emissions. Under normal operating conditions, requiring lower levels of ignition energy, this system consumes less power than current OEM systems.
This ignition was originally developed to enhance lean combustion. It was first tested at the Arthur D. Little laboratories, showing fuel economy gains of 6 to 10% were feasible. The biggest benefit comes from the extension of the lean limit, reducing the level of NOx created in a lean-burn engine.

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