Abstract: A method of minimizing engine noise emitted from a motor vehicle air intake system. An objective function to be minimized, such as emitted engine noise, is selected. A model of a motor vehicle engine and intake manifold as an acoustic source is generated. Next, a model of required air induction system components is generated. A set of air induction system components and system dimensional constraints is selected. A model of the air induction system is then created given the generated models of the acoustic source and the required induction system components, the selected air induction system components and the system dimensional constraints to thereby minimize the objective function. The methodology of the present invention minimizes the guesswork associated with multi-component induction system design, as it ties all functions together into a model that can be easily manipulated as needed in response to changing design parameters.

Abstract: An engine induction system resonator that is designed to minimize emitted engine noise. The resonator includes an enclosed tube that has a first diameter and that defines a resonant chamber therein. The resonator also includes a pipe that has a second diameter smaller than the tube diameter. The pipe extends axially through the tube and has first and second ends that connect to other induction system components to channel inductive air flow therethrough. The pipe defines a plurality of perforated holes distributed along a section of the pipe housed within the tube. The plurality of perforated holes is distributed along the pipe in a manner that minimizes emitted engine noise. The resonator is designed in view of other system components to minimize overall system cost and overall required system implementation area.

Abstract: An apparatus and corresponding method for detecting misfires of a motor vehicle internal combustion engine. The apparatus includes a speed sensor for generating a signal. Also, the apparatus includes a filter means for filtering noise-related events from said signal corresponding to sensed engine speed to thereby produce a filtered output signal. In addition, a pressure sensor for measuring average manifold absolute pressure over a cylinder firing event to set a misfire threshold change in engine speed value is shown. A comparison means for comparing said filtered output signal with said threshold change in engine speed value to detect an engine misfire condition for said cylinder firing event is also included.

Abstract: A digital filter system is used in an internal combustion engine misfire detection system. The digital filter system includes a signal input for inputting a digital signal generated in response to sensed crankshaft angular velocity. A plurality of digital filters is connected to the signal input, with each of the filters being activated over a predetermined range of engine speeds. Each of the plurality of digital filters, upon being activated, operates as a bandpass filter to filter the digital signal at an engine spatial firing frequency and at a predetermined number of multiples of the engine spatial firing frequency. A signal output is also connected to the plurality of digital filters for outputting the filtered digital signal for engine misfire detection purposes.