Ifp Energies Nouvelles

Dominique Auclair

Alexandre Pagot

Laurent Duval

Jean-Marc Zaccardi

Benoist Thirouard

Olivier Lejeune

Olivier Masson

A method for detection of abnormal combustion for internal combustion engines is disclosed. A physical model is chosen that describes, as a function of the angle &#x3b1; of rotation of the engine crankshaft, the development of pressure in the cylinder during combustion without any pre-ignition phenomenon. The cylinder pressure P(&#x3b1;) is estimated using this model and the intake pressure is measured. The beginning of abnormal combustion is detected by comparing a first value of a variable calculated using the measurement of the cylinder pressure, to a second value of the variable calculated using the estimation of the cylinder pressure. The amplitude of the pre-ignition is determined by repeating these steps for a defined number of crankshaft angles. Then the progress of the abnormal combustion detected in the combustion chamber is controlled as a function of the amplitude of the pre-ignition phenomenon.

Method for detection of abnormal combustion for internal combustion engines

The invention is an abnormal combustion detection method for spark-ignition internal-combustion engines. For each engine cycle, a parameter characterizing a distribution of N combustion indicator values, CA10 for example, acquired over N cycles preceding the cycle in progress, is determined while ignoring extreme values. A threshold is defined from this parameter for the combustion indicator. The start of an abnormal combustion is then detected by comparing the combustion indicator with this threshold and the course of the abnormal combustion detected in the combustion chamber is controlled.

Abnormal combustion detection method for internal-combustion engines

A method for determining as a function of time the angle of rotation of a crankshaft by estimating the position of missing teeth on a target wheel is disclosed which has application to engine control. A sensor acquires, as a function of time, a periodic signal comprising a pulsating waveform, each pulse indicating the passage of a tooth past this sensor. The position of a missing pulse on the signal is estimated from a missing tooth on the target wheel, by: estimating, during a cycle N, a time interval S between the passage past the sensor of a tooth dpreceding the missing tooth d and the passage past the sensor of a tooth dfollowing missing tooth d, by means of the time interval between the passages of the same teeth during the previous cycle N&#x2212;1 then, estimating the position of the missing pulse in this interval S, according to the position of the pulses in time interval A between the passage past the sensor of tooth d&#x2212;r and the passage past the sensor of tooth d&#x2212;r during cycle N, with the engine being a j-stroke (2 or 4) engine and comprising k cylinders and a target wheel with l teeth, including the missing tooth; finally, determining as a function of time the crankshaft rotation angle by the modified signal.

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Villiers sur Marne, France

Dominique Auclair