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Certain harmonics of angular crankshaft velocity are indicative of engine imbalance induced by cylinder misfire. Application of the Digital Fourier Transformation (DFT) facilitates the production-feasible calculation of a singular index in the frequency domain indicative either of smooth engine operation or misfire. The phase of that particular index with proper interpretation directly points to a misfiring cylinder. The identification of a misfiring pair, either opposing or a non-opposing in the cylinder bank, requires a bit more sophisticated approach since the phase response of the characteristic index in the frequency domain becomes more complex. The method demonstrated here was successfully applied in real time in four-, six-, and eight-cylinder engines, both SI and Diesel, for the On-Board Diagnostic application with reliability exceeding relevant regulatory requirements.

In today's dynamic automotive environment, reducing the lead-time to introduce new product technologies to the market place can be a key competitive advantage. Employing proactive risk reduction techniques to define key product and process relationships is essential to enhance the production worthiness of a design while it is still in the advanced development phase of the program. This paper describes how Delphi Powertrain Systems applied the Shainin proactive risk reduction methodology in advanced product development to focus resources on understanding and mitigating the risk associated with the development of a new Delphi ammonia sensor. Organizational and technical strategies to accelerate profound knowledge capture, along with corresponding test results, are presented and discussed.