US5909724A — Engine control method

Claim 1

Independent Claim 116 words

An engine combustion condition judging method for detecting a crank angle speed of a multiple cylinder engine to judge a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, wherein the improvement comprises steps of; setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder to the given cylinder in an engine cycle for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within said predetermined crank angle range.

Claim 2

Dependent Claim 116 words

An engine combustion condition judging method for detecting a crank angle speed of a multiple cylinder engine to judge a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, wherein the improvement comprises steps of; setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder to the given cylinder in an engine cycle for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within said predetermined crank angle range.

Claim 3

Dependent Claim 34 words

A method as recited in claim 1 wherein said predetermined crank angle range for detecting the crank angle speed property is determined in a second half of an expansion stroke of the engine cycle.

Claim 4

Dependent Claim 39 words

A method as recited in claim 1 wherein said predetermined crank angle range is determined within a range of 100° crank angle to 200° crank angle after a top dead center of the second half of the expansion stroke.

Claim 5

Dependent Claim 22 words

A method as recited in claim 1 wherein said the predetermined crank angle range is set not smaller than 60° crank angle.

Claim 6

Dependent Claim 44 words

A method as recited in claim 1 wherein a crank angle speed or equivalent thereof is measured for detecting the crank angle speed property, and wherein frequency components corresponding to an engine explosive rotation degree are excluded in detecting the crank angle speed property.

Claim 7

Dependent Claim 59 words

A method as recited in claim 1 wherein the engine is provided with multiple cylinders, each of which combustion condition is judged, wherein a crank angle speed or equivalent thereof is measured for detecting the crank angle speed property, and wherein frequency components corresponding to an engine explosive rotation degree are excluded in detecting the crank angle speed property.

Claim 8

Dependent Claim 52 words

A method as recited in claim 1 wherein the frequency components corresponding to the explosive rotation degree of the engine can be removed by obtaining a difference in the detected data of the crank angle speed between the current cycle and the precedent cycle to obtain a crank angle speed change profile.

Claim 9

Dependent Claim 27 words

A method as recited in claim 6 wherein the frequency components corresponding to the engine explosive rotation degree is removed only in the high engine speed range.

Claim 10

Dependent Claim 46 words

A method as recited in claim 6 wherein a crank angle speed or equivalent thereof is measured for detecting the crank angle speed property, and wherein frequency components having degrees lower than 0.5 of the engine rotation is excluded in detecting the crank angle speed property.

Claim 11

Dependent Claim 145 words

An engine control method comprising steps of; detecting a crank angle speed of a multiple cylinder engine, for judging a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within the predetermined crank angle range, and controlling an air fuel ratio based on the judgment of the combustion condition in a lean burn operation in which the air fuel ratio is controlled to a value greater than the theoretical value in a predetermined operating range of the engine.

Claim 12

Dependent Claim 145 words

An engine control method comprising steps of; detecting a crank angle speed of a multiple cylinder engine, for judging a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within the predetermined crank angle range, and controlling an air fuel ratio based on the judgment of the combustion condition in a lean burn operation in which the air fuel ratio is controlled to a value greater than the theoretical value in a predetermined operating range of the engine.

Claim 13

Dependent Claim 21 words

A method as recited in claim 10 wherein an air fuel control ratio gain is controlled based on the combustion condition.

Claim 14

Dependent Claim 116 words

An engine control system, comprising; crank angle speed detecting means for detecting a crank angle speed or equivalent thereto of an engine in a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder for detecting a crank angle speed property, combustion condition judging means for judging the combustion condition based on said crank angle speed property within the predetermined crank angle range, and, air fuel ratio control means for controlling an air fuel ratio of the engine in accordance with the judgment of the combustion condition judging means.

Claim 15

Dependent Claim 116 words

An engine control system, comprising; crank angle speed detecting means for detecting a crank angle speed or equivalent thereto of an engine in a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminates in a given cylinder and another crank angle at which a combustion substantially starts in the next cylinder for detecting a crank angle speed property, combustion condition judging means for judging the combustion condition based on said crank angle speed property within the predetermined crank angle range, and, air fuel ratio control means for controlling an air fuel ratio of the engine in accordance with the judgment of the combustion condition judging means.

Claim 16

Dependent Claim 38 words

An engine control system as recited in claim 12 further comprising detected data processing means for excluding frequency components corresponding to an engine explosive rotation degree and those having degrees lower than 0.5 degree of the engine rotation.

Claim 17

Dependent Claim 78 words

An engine control system as recited in claim 12 wherein the air fuel ratio control means comprises an air fuel control gain setting means for setting a target air fuel control gain which provides a greater air fuel ratio than a theoretical air fuel ratio in a predetermined lean burn operation range and an air fuel ratio control gain compensation means for compensating the air fuel control gain base on the judgement to the combustion condition judgement means.

Claim 18

Dependent Claim 99 words

An engine control system as recited in claim 12 wherein the combustion condition judging means judges the combustion condition in the cylinder by comparing the crank angle speed change property with a first set value and a second set value lower than the first set value, the air fuel ratio compensation means compensates the air fuel ratio control gain to make an intake gas mixture rich when the crank angle speed fluctuation is greater than the first set value, and make the intake gas mixture lean when the crank angle speed fluctuation is smaller than the second set value.

Claim 19

Dependent Claim 58 words

An engine control system as recited in claim 12 wherein the crank angle speed detecting means detects the crank angle speed property or equivalent there to of the engine in the predetermined crank angle range selectively determined within the crank angle range between 100° crank angle and 200° crank angle after top dead center in the expansion stroke.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2002-06-07	2002-12-07	2003-06-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2006-06-07	2006-12-07	2007-06-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2010-06-07	2010-12-07	2011-06-08	$7700.00	Window Closed / Lapsed

Engine control method

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