Abstract: A method of mounting an accelerometer to an internal combustion engine comprises securing the accelerometer to a mating surface on an engine component external to a combustion chamber where the accelerometer can generate a signal output that is characteristic of engine knock, when it occurs, and at least one other combustion behavior inside the combustion chamber during a combustion event. The method further comprises connecting a signal wire at one end to the accelerometer and at an opposite end to a signal processor, and increasing the signal output's signal-to-noise ratio.

Abstract: In the case of non-execution of catalyst warm-up acceleration control, the engine misfire detection procedure compares a 30-degree rotation time computed as a time required for a 30-degree rotation of an engine crankshaft with preset reference values Tref1 and Tref2 and distinctly detects the occurrence of intermittent engine misfires and the occurrence of either a single engine misfire or consecutive engine misfires (steps S120 to S150). In the case of execution of the catalyst warm-up acceleration control, the engine misfire detection procedure compares the 30-degree rotation time computed as the time required for a 30-degree rotation of the engine crankshaft with preset reference values Tref3 and Tref4 and distinctly detects the occurrence of the consecutive engine misfires and the occurrence of either the single engine misfire or the intermittent engine misfires (steps S160 to S190).

Abstract: A computer implemented system for engine misfire detection employs a crankshaft-originated speed signal that includes normal variability due to target wheel tooth error and the like. A Discrete Fourier Transform (DFT) is performed on the speed signal to convert it into a frequency-domain raw misfire detection metric. The system is configured to normalize the raw misfire detection metric using a non-misfire metric that is obtained by and corresponds to non-misfire operation of an internal combustion engine. A resulting normalized misfire detection metric has such normal variations removed leaving variations attributable to misfire. The system detects a misfire when the normalized misfire detection metric exceeds a predetermined threshold and is bounded by a predetermined phase angle region. The system detects both continuous misfire as well as intermittent misfire. The system also detects single cylinder misfire and multiple cylinder misfire.

Abstract: A method to dynamically determine a parametric value for combustion chamber deposits (CCD), e.g. in a controlled auto-ignition engine, including in-situ evaluation of thickness of CCD, based on a sensor which monitors combustion in a homogeneous charge compression ignition engine. It includes a temperature sensor operative to monitor the combustion chamber, and a CCD parameter that is based upon a peak combustion temperature measured at a crank angle. A CCD parameter can also be determined utilizing an in-cylinder pressure monitor, wherein a combustion chamber deposit parameter is based upon crank angle location of a peak in-cylinder pressure parameter.