# US 5,349,299 A · Fuel supply misfire-detecting system for internal combustion engines

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- Number: US 5,349,299 A
- Document ID: US5349299A
- Status: Granted
- Kind: A
- Application number: 07/989,438
- Filed: 1992-12-11
- Granted: 1994-09-20
- Earliest claimed: 1991-12-13
- Assignees: Honda Giken Kogyo Kabushiki Kaishi
- Inventors: Masaki Kanehiro; Yuichi Shimasaki; Takuji Ishioka; Shigeki Baba; Takashi Hisaki; Shigeru Maruyama; Masataka Chikamatsu; Shukoh Terata; Kenichi Maeda; Kazuhito Kakimoto
- Web page: https://patentgrep.com/patent/US5349299A

## CPC

- F02P 17/12: Testing characteristics of the spark, ignition voltage or current (testing of sparking plugs H01T13/60)
- F02P 2017/125: {Measuring ionisation of combustion gas, e.g. by using ignition circuits}
- F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00)

## Abstract

A misfire-detecting system detects a misfire occurring in an internal combustion engine. A value of sparking voltage for discharging a spark plug of the engine is detected. A differentiating circuit differentiates the detected value of the sparking voltage. A misfire-determining circuit compares the differential value of the sparking voltage with a predetermined value, and determines, based upon a result of the comparison, whether a misfire has occurred in the engine.

## Claims

### Claim 1

In a misfire-detecting system for detecting a misfire occurring in an internal combustion engine having an ignition system including at least one spark plug, engine operating condition-detecting means for detecting values of operating parameters of said engine, signal-generating means for determining ignition timing of said engine, based upon values of operating parameters of said engine detected by said engine operating condition-detecting means and generating an ignition command signal indicative of said determined ignition timing, and sparking voltage-generating means responsive to said ignition command signal for generating sparking voltage for discharging said at least one spark plug, and voltage value-detecting means for detecting a value of said sparking voltage generated by said sparking voltage-generating means after generation of said ignition command signal, the improvement comprising:
differentiating means, connected to said voltage value-detecting means, for differentiating a value of said sparking voltage detected by said voltage value-detecting means;
misfire-determining means, connected to said differentiating means, for comparing a differential value of said sparking voltage obtained by said differentiating means with a predetermined value, and for determining, based upon a result of said comparison, whether a misfire has occurred in said engine; and
time period-limiting means, inserted into a path from said voltage value-detecting means to said misfire-determining means and connected to said signal generating means, for setting a comparison period of time upon which said comparison, of said differential value of said sparking voltage with said predetermined value, is to be made, and wherein said misfire-determining means compares said differential value of said sparking voltage with said predetermined value to determine occurrence of a misfire solely during said comparison period of time set by said time period-setting means.

### Claim 2 (depends on 1)

A misfire-detecting system as claimed in claim 1, further including delay means, inserted into a path from said voltage value-detecting means to said misfire-determining means, for delaying a value of said sparking voltage detected by said voltage-detecting means, by a predetermined period of time, and wherein said misfire-determining means compares a value of said sparking voltage delayed by said delay means and differentiated by said differentiating means with said predetermined value.

### Claim 3 (depends on 2)

A misfire-detecting system as claimed in claim 2, wherein said time period-limiting means sets said comparison period of time at a time which is delayed by a period of time corresponding to said predetermined period of time by which said detected value of said sparking voltage is delayed by said delay means.

### Claim 4 (depends on 1, 2, 3)

A misfire-detecting system as claimed in any of claims 1, 2 or 3, further including second misfire-determining means, connected to said voltage value-detecting mean said second misfire-determining means measures a period of time over which a value of said sparking voltage detected by said voltage-detecting means exceeds a predetermined value, and determines that a misfire has occurred, when said measured period of time exceeds a predetermined value.

### Claim 5 (depends on 1, 2, 3)

A misfire-detecting system as claimed in any of claims 1, 2 or 3, further including third misfire-determining means, connected to said voltage value-detecting means, for comparing a value of said sparking voltage detected by said voltage value-detecting means with a predetermined value after a predetermined period of time has elapsed after generation of said ignition command signal, and determining, based upon a result of said last-mentioned comparison, whether a misfire has occurred in said engine.