Method and system for engine auto-ignition detection and mitigation
First Claim
1. A method for detecting and mitigating auto ignition in a cylinder of an internal combustion engine, the method comprising:
- providing a first sensor for sensing a crank angle of a crankshaft of the engine;
providing a second sensor for detecting a knock intensity signal in the cylinder of the engine;
determining the crank angle using the first sensor;
calculating a knock intensity signal indicative of the cylinder pressure when the crank angle is between a first predetermined crank angle and a second predetermined crank angle;
determining at least one characteristic of the knock intensity signal, wherein the at least one characteristic is an amplitude of the knock intensity signal;
comparing the at least one characteristic of the knock intensity signal to at least one predetermined characteristic;
determining if the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic; and
performing at least one auto ignition mitigating action when the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic, wherein the at least one auto ignition mitigating action is selected from the group consisting of;
(a) enriching a fuel flow to the cylinder when an engine speed is between a first predetermined engine speed threshold and a second predetermined engine speed threshold and an engine load is between a first predetermined engine load threshold and a second predetermined engine load threshold;
(b) shutting off a fuel flow into the cylinder when an engine speed is between a third predetermined engine speed threshold and a fourth predetermined engine speed threshold, and the engine load is between a third predetermined engine load threshold and a fourth predetermined engine load threshold;
(c) adjusting an air intake camshaft position when engine speed is between a fifth predetermined engine speed threshold and a sixth predetermined engine speed threshold and the engine load is between a fifth predetermined engine load threshold and a sixth predetermined engine load threshold; and
(d) preventing a short term ignition retard when engine speed is between the first predetermined engine speed threshold and a seventh predetermined engine speed threshold and the engine load is between a seventh predetermined engine load threshold and a eighth predetermined engine load threshold.
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Accused Products
Abstract
A system and method for detecting and mitigating automatic ignition in a cylinder of an internal combustion engine. The method includes providing a first sensor for sensing and determining a crank angle of a crankshaft of the engine. A second sensor is provided for detecting a change in an engine vibration frequency caused by Auto Ignition (AI). The engine vibration signal of the second sensor is processed into a knock intensity signal. The knock intensity signal is indicative of the cylinder pressure and is acquired when the crank angle is between a first predetermined crank angle and a second predetermined crank angle. At least one characteristic of the knock intensity signal is determined and the at least one characteristic of the knock intensity signal is compared to at least one predetermined characteristic threshold. If the at least one characteristic of the knock intensity signal is determined to exceed the at least one predetermined characteristic threshold, then at least one auto ignition mitigating action is performed to mitigate the auto ignition event.
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Citations
8 Claims
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1. A method for detecting and mitigating auto ignition in a cylinder of an internal combustion engine, the method comprising:
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providing a first sensor for sensing a crank angle of a crankshaft of the engine; providing a second sensor for detecting a knock intensity signal in the cylinder of the engine; determining the crank angle using the first sensor; calculating a knock intensity signal indicative of the cylinder pressure when the crank angle is between a first predetermined crank angle and a second predetermined crank angle; determining at least one characteristic of the knock intensity signal, wherein the at least one characteristic is an amplitude of the knock intensity signal; comparing the at least one characteristic of the knock intensity signal to at least one predetermined characteristic; determining if the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic; and performing at least one auto ignition mitigating action when the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic, wherein the at least one auto ignition mitigating action is selected from the group consisting of; (a) enriching a fuel flow to the cylinder when an engine speed is between a first predetermined engine speed threshold and a second predetermined engine speed threshold and an engine load is between a first predetermined engine load threshold and a second predetermined engine load threshold; (b) shutting off a fuel flow into the cylinder when an engine speed is between a third predetermined engine speed threshold and a fourth predetermined engine speed threshold, and the engine load is between a third predetermined engine load threshold and a fourth predetermined engine load threshold; (c) adjusting an air intake camshaft position when engine speed is between a fifth predetermined engine speed threshold and a sixth predetermined engine speed threshold and the engine load is between a fifth predetermined engine load threshold and a sixth predetermined engine load threshold; and (d) preventing a short term ignition retard when engine speed is between the first predetermined engine speed threshold and a seventh predetermined engine speed threshold and the engine load is between a seventh predetermined engine load threshold and a eighth predetermined engine load threshold. - View Dependent Claims (2, 3, 4)
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5. A method for detecting and mitigating auto ignition in a cylinder of an internal combustion engine, the method comprising:
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providing a first sensor for detecting a cylinder pressure in the cylinder of the engine; calculating a knock intensity signal indicative of the cylinder pressure during an engine crank cycle; determining at least one characteristic of the knock intensity signal; comparing the at least one characteristic of the knock intensity signal to at least one predetermined characteristic, wherein the at least one characteristic is an amplitude of the knock intensity signal; determining if the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic; and performing at least one auto ignition mitigating action when the at least one characteristic of the knock intensity signal exceeds the at least one predetermined characteristic, wherein the at least one auto ignition mitigating action is selected from the group consisting of; (a) enriching a fuel flow to the cylinder when an engine speed is between a first predetermined engine speed threshold and a second predetermined engine speed threshold and an engine load is between a first predetermined engine load threshold and a second predetermined engine load threshold; (b) shutting off a fuel flow into the cylinder when an engine speed is between a third predetermined engine speed threshold and a fourth predetermined engine speed threshold, and the engine load is between a third predetermined engine load threshold and a fourth predetermined engine load threshold; (c) adjusting an air intake camshaft position when engine speed is between a fifth predetermined engine speed threshold and a sixth predetermined engine speed threshold and the engine load is between a fifth predetermined engine load threshold and a sixth predetermined engine load threshold; and (d) preventing a short term ignition retard when engine speed is between the first predetermined engine speed threshold and a seventh predetermined engine speed threshold and the engine load is between a seventh predetermined engine load threshold and a eighth predetermined engine load threshold. - View Dependent Claims (6, 7, 8)
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Specification