Method and device for automatically adjusting the spark advance of a controlled ignition engine
AssigneeInstitut Francais du Petrole
InventorsAndre Douaud, Joseph Rialan
Life of this patent
Estimating the term…
Abstract
An accelerometer located on the cylinder head of an engine supplies a signal which is twice integrated thus giving a resulting signal whose peak value is detected. The spark advance is automatically adjusted so that this peak value occurs in a preselected angular position of the crankshaft. The advance may also be similarly adjusted based instead on the null point of the signal which results after an integration of the signal coming from the accelerometer.
Claims9
A method for automatically adjusting the ignition timing of a controlled ignition engine to the optimum value of this timing for any working condition of the engine corresponding to the maximum output and efficiency of the engine, wherein the ignition timing is so adjusted that the pressure peak in at least one cylinder occurs at a predetermined angular position of the drive shaft of the engine, this method comprising:
- determining the angular position of the drive shaft,
- detecting the accelerations at a location on the cylinder head of the engine and providing, during at least a selected fraction of the rotation of the drive shaft and in a low frequency band, a first signal corresponding to these accelerations,
- integrating said first signal to obtain a second signal for determining the null value of said second signal with respect to the angular position of the drive shaft, and
- adjusting the ignition timing as a function of the angular position of the drive shaft corresponding to the determined null value of said second signal.
A device for automatically adjusting the ignition timing of an engine, comprising ignition control means and a detector of the angular rotation of the engine drive shaft, wherein the device comprises an accelerometer secured to the cylinder head of the engine for generating a first signal representing the accelerations to which the cylinder head is subjected at the point of location of the accelerometer, a low pass filter connected to said accelerometer for filtering said first signal, an integrator connected to said filter for generating a second signal, first detecting means connected to said integrator for detecting a zero value of said second signal during at least a portion of the rotation of the engine drive shaft, second detecting means connected to said means for detecting the zero value of the second signal and to said detector of angular rotation, for detecting the angular position of the drive shaft corresponding to the zero value of the second signal, comparing means connected to said second detecting means for measuring the difference between said angular position and a reference angular position, and adjusting means connected to said comparing means for adjusting said ignition control means as a function of said difference.
Dependencies are inferred from the claim text.