Visteon Global Technolgoies, Inc.

Bruce Wang

Guoming Zhu

Kenneth L Gould

Garlan J Huberts

Kevin David Moran

Michael T Nation

David Lee Porter

Chao Fu Daniels

Constantine Panagos

Two embodiments of an integrated ionization detection circuit and ignition coil driver, an ASIC and a single electronic package, are disclosed. The apparatuses reduce the cost and complexity of an in-cylinder ionization detection system by combining like functionality into one ASIC or electronic module easing packaging constraints. In both embodiments, a current sink is used. The current sink removes noise in the form of voltage splices. The voltage spikes are high voltage, but of short duration. The current sink prevents these spikes from turning on the IGBT. However, the current sink allows the IGBT command signal to pass. This device also comprises a switch whereby ionization current and coil primary current are multiplexed.

Device for reducing the part count and package size of an in-cylinder ionization detection system by integrating the ionization detection circuit and ignition coil driver into a single package

The present feature of the invention is generally directed to a subsystem of an ignition diagnostics and feedback control system using ionization current feedback. It utilizes the ionization signal from an ionization detection circuit to monitor ignition parameters, such as primary charge timing, primary charge duration, ignition/spark timing, and ignition/spark duration for future 'smart' ignition system control. In addition, the ionization signal is also used to detect spark plug carbon fouling, as well as plug insulator overheating. These parameters can be monitored for every cylinder of the engine for each engine cycle.

Ignition diagnosis using ionization signal

A circuit for measuring ionization current in a combustion chamber of an internal combustion engine including an ignition coil, having a primary winding and a secondary winding, and an ignition plug. The ignition plug ignites an air/fuel mixture in the combustion chamber and produces an ignition current in response to ignition voltage from the ignition coil. A capacitor, charged by the ignition coil, provides a bias voltage producing an ionization current after ignition of the air/fuel mixture in the combustion chamber. A current mirror circuit produces an isolated current signal proportional to the ionization current. In the present invention, the ignition current and the ionization current flow in the same direction through the secondary winding of the ignition coil. The charged capacitor operates as a power source and, thus, the ignition current flows from the charged capacitor through the current mirror circuit and the ignition coil to the ignition plug.

Circuit for measuring ionization current in a combustion chamber of an internal combustion engine

In a first preferred embodiment, the present feature of the invention multiplexes both the ionization and driver current feedback signals into one signal, thus reducing cost and making coil packaging easier. The multiplexed signal first outputs the ionization detection signal and then replaces the ionization signal with the charge current feedback signal when the charge command Vis enabled. In other words, the multiplexed feedback signal outputs the ionization feedback signal and switches to the charge current feedback signal when the charge command Vis active. In a second preferred embodiment, the present feature of the invention comprises a method and apparatus to multiplex the ignition driver gate signal with both the ignition coil charge current feedback signal and the ionization signal, thus reducing the package pin count by two.

Method for reducing pin count of an integrated coil with driver and ionization detection circuit by multiplexing ionization and coil charge current feedback signals

A charge pump is used to supply current to the ionization detection circuit. To detect in-cylinder ions generated during the combustion process, a DC bias voltage needs to be applied. There are two ways to generate the DC bias: conventional DC power supply (large electronics) and capacitor charges by primary or secondary flyback voltage (high voltage capacitor). Typically, flyback voltage is used to charge the capacitor which supplies current to the ionization detection circuit. This necessitates the use of high voltage capacitors. Generally, ceramic capacitors are used. However, as temperature fluctuates, the board that the capacitor is mounted on can flex, causing the ceramic capacitor to crack. This invention proposes to use a high voltage charge pump to provide enough DC bias voltage for measuring ionization current. In a preferred embodiment, a model number M1C4827 EL driver is used in the charge pump circuit. The charge pump circuit will convert the 12 Volt DC at the B+ terminal to a 90 to 100 volt pulse train with a pulse repetition frequency of 500 kHz at the charge pump output.

Device to provide a regulated power supply for in-cylinder ionization detection by using a charge pump

Internal combustion engine (ICE) on-plug ignition coils with transistor drivers located in powertrain control modules (PCM) or other remote locations are prone to high electrical and magnetic interference (EMI) emissions and are subject to interference from other components due to long connecting wires. Ionization detection circuits have even greater sensitivity to EMI because of their very low signal current levels (mioroampere). The present feature of the invention integrates both the coil driver transistor and ionization detection circuits into the on-plug ignition coil. By placing the circuit on top or on the side of the coil, the connection distance from the circuit to the secondary winding is minimized. Thus, the circuit is less susceptible to electrical and electromagnetic noise.

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Troy, MI, United States of America

Bruce Wang