Self diagnosing ignition control
First Claim
1. A self-diagnosing ignition control apparatus for driving sequential first and second drive signals across spaced electrodes of a spark plug in an engine cylinder to ignite an air/fuel mixture in the engine cylinder and to diagnose improper ignition of the air/fuel mixture, comprising:
- a double strike ignition drive circuit having an ignition coil for delivering sequential first and second drive signals to the spark plug producing respective first and second arcs across the spark plug electrodes, the first arc for igniting the air/fuel mixture and the second arc for measuring a frequency band of energy trapped in the ignition coil;
a measurement circuit coupled to the ignition coil and having a network with a predetermined natural frequency, the network disposed between a terminal of the ignition coil and a ground reference, wherein the second drive signal includes a frequency component substantially at the predetermined natural frequency when improper ignition occurs and wherein the second drive signal does not include a frequency component at the predetermined natural frequency when proper ignition occurs; and
the measurement circuit further comprising diagnostic circuitry for diagnosing the improper ignition by distinguishing excitation of the natural frequency of the network when a frequency component is present in the second drive signal substantially at the predetermined natural frequency.
1 Assignment
0 Petitions
Accused Products
Abstract
A self-diagnosing ignition drive circuit for applying a first ignition drive signal to a spark plug in an internal combustion engine cylinder for generating an arc across the electrodes thereof to ignite an air/fuel mixture in the cylinder and, following a delay period, applying a second ignition drive signal to the spark plug for generating a second arc across the electrodes to contribute combustion energy and to provide for measurement of the frequency content of energy trapped in an ignition coil during combustion. If the frequency content includes a predetermined frequency, improper ignition in the cylinder is diagnosed through excitation of a natural frequency of a misfire detection circuit coupled to the ignition coil corresponding to at least one engine cylinder.
-
Citations
14 Claims
-
1. A self-diagnosing ignition control apparatus for driving sequential first and second drive signals across spaced electrodes of a spark plug in an engine cylinder to ignite an air/fuel mixture in the engine cylinder and to diagnose improper ignition of the air/fuel mixture, comprising:
-
a double strike ignition drive circuit having an ignition coil for delivering sequential first and second drive signals to the spark plug producing respective first and second arcs across the spark plug electrodes, the first arc for igniting the air/fuel mixture and the second arc for measuring a frequency band of energy trapped in the ignition coil; a measurement circuit coupled to the ignition coil and having a network with a predetermined natural frequency, the network disposed between a terminal of the ignition coil and a ground reference, wherein the second drive signal includes a frequency component substantially at the predetermined natural frequency when improper ignition occurs and wherein the second drive signal does not include a frequency component at the predetermined natural frequency when proper ignition occurs; and the measurement circuit further comprising diagnostic circuitry for diagnosing the improper ignition by distinguishing excitation of the natural frequency of the network when a frequency component is present in the second drive signal substantially at the predetermined natural frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A self-diagnosing ignition control circuit for applying ignition drive signals to a spark plug with spaced electrodes in an internal combustion engine cylinder for igniting an air/fuel mixture in the engine cylinder, comprising:
-
an ignition drive circuit including an ignition coil with opposing upper and lower electrical terminals, the upper electrical terminal coupled to the spark plug for applying sequential first and second drive signals to the spark plug for generating first and second arcs across the spaced electrodes; a misfire detection circuit having an input terminal, an output terminal and a network coupled between the input terminal and a ground reference, the input terminal coupled to the lower electrical terminal of the ignition coil, the network being tuned to a predetermined frequency; and the predetermined frequency selected as a frequency that is present in said drive signals at the lower electrical terminal in the absence of combustion in the engine cylinder and that is not present in said drive signals in the presence of combustion in the engine cylinder; wherein presence of the predetermined frequency in the second drive signal excites frequency of the network, causing a signal perturbation at the output terminal of the misfire detection circuit indicating improper combustion of the air/fuel mixture. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
Specification