# US 10,767,592 B2 · Failure diagnosis device for in-cylinder pressure sensor

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- Number: US 10,767,592 B2
- Document ID: US10767592B2
- Status: Granted
- Kind: B2
- Application number: 16/459,969
- Filed: 2019-07-02
- Published: 2020-03-05
- Granted: 2020-09-08
- Earliest claimed: 2018-09-03
- Assignees: Mazda Motor Corporation
- Applicants: Mazda Motor Corporation
- Inventors: Shoji Fujiwara; Hidetoshi Hashimoto; Takuji Okumura; Shigeru Nakagawa; Yasushi Torii; Masayuki Kinoshita; Yuichiro Tsumura; Daisuke Tanaka; Taiki Maiguma
- Web page: https://patentgrep.com/patent/US10767592B2

## CPC

- F02D 35/023: {by determining the cylinder pressure}
- F02D 41/222: {relating to the failure of sensors or parameter detection devices}
- F02B 77/085: {with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame}
- F02D 41/123: {the fuel injection being cut-off}
- F02P 5/045: {combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02)}
- F02P 5/151: {with means for compensating the variation of the characteristics of the engine or of a sensor, e.g. by ageing}
- G01M 15/08: by monitoring pressure in cylinders
- G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)}
- G07C 5/0825: {using optical means}
- G08B 21/182: {Level alarms, e.g. alarms responsive to variables exceeding a threshold}
- F02D 41/3041: {with means for triggering compression ignition, e.g. spark plug}
- F02D 2200/021: Engine temperature
- F02D 2200/024: Fluid pressure of lubricating oil or working fluid
- Y02T 10/40: Engine management systems
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- 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)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A failure diagnosis device for an in-cylinder pressure sensor includes an in-cylinder pressure sensor, and a controller comprised of circuitry configured to execute a diagnosis module into which a signal of the in-cylinder pressure sensor is inputted and configured to diagnose a failure of the sensor based on the signal. The diagnosis module includes a reading module configured to read the signals of the in-cylinder pressure sensor at a first timing that is a timing retarded by a specific crank angle from a compression top dead center, and at a second timing that is a timing advanced by the specific crank angle from the compression top dead center, and a failure determining module configured to determine that the in-cylinder pressure sensor has failed when the failure determining module determines that a difference between signal values at the first timing and at the second timing exceeds a predefined threshold.

## Claims

### Claim 1

A failure diagnosis device for an in-cylinder pressure sensor, comprising:
an in-cylinder pressure sensor disposed so as to face to the inside of a combustion chamber of an engine mounted to an automobile, and configured to output a signal corresponding to a pressure inside the combustion chamber; and
an engine controller comprised of circuitry configured to execute a diagnosis module into which the signal of the in-cylinder pressure sensor is inputted to diagnose a failure of the in-cylinder pressure sensor based on the signal of the in-cylinder pressure sensor,
the diagnosis module including:
a reading module configured to read the signal of the in-cylinder pressure sensor at a predefined first timing that is a timing retarded by a specific crank angle from a compression top dead center, and the signal of the in-cylinder pressure sensor at a predefined second timing that is a timing advanced by the specific crank angle from the compression top dead center; and
a failure determining module configured to determine that the in-cylinder pressure sensor has failed when the failure determining module determines that a difference between a signal value of the in-cylinder pressure sensor at the first timing and a signal value of the in-cylinder pressure sensor at the second timing exceeds a predefined threshold.

### Claim 2 (depends on 1)

The failure diagnosis device of claim 1, wherein the diagnosis module makes the threshold smaller as a speed of the engine increases.

### Claim 3 (depends on 1)

The failure diagnosis device of claim 1, wherein the diagnosis module makes the threshold larger as an amount of air filled up in the combustion chamber increases.

### Claim 4 (depends on 1)

The failure diagnosis device of claim 1,
wherein the failure determining module repeatedly performs a comparison of the difference with the threshold, and
wherein the failure determining module determines that the in-cylinder pressure sensor has failed when a determination that the difference exceeds the threshold is made continuously a plurality of times.

### Claim 5 (depends on 4)

The failure diagnosis device of claim 4, further comprising an engine control module into which a signal of a one or more sensors at least including the in-cylinder pressure sensor is inputted and configured to operate the engine based on the signal of the one or more sensors,
wherein the engine control module stops a supply of fuel to the engine when a fuel cut condition is satisfied while the automobile travels, and
wherein the diagnosis module performs the failure diagnosis of the in-cylinder pressure sensor while the engine control module stops the supply of fuel to the engine.

### Claim 6 (depends on 5)

The failure diagnosis device of claim 5, further comprising an ignition plug disposed so as to face to the inside of the combustion chamber and configured to ignite a mixture gas inside the combustion chamber in response to an ignition signal of the engine control module,
wherein a portion of the mixture gas inside the combustion chamber starts combustion accompanied by flame propagation, by forcible ignition of the ignition plug, and remaining unburnt mixture gas then combusts by self-ignition,
wherein the engine control module outputs the ignition signal to the ignition plug before a target timing so that the unburnt mixture gas self-ignites at the target timing, and
wherein the engine control module estimates a timing at which the unburnt mixture gas self-ignites based on the signal of the in-cylinder pressure sensor.

### Claim 7 (depends on 1)

The failure diagnosis device of claim 1, wherein the diagnosis module includes an informing device configured to inform of the failure when the failure determining module determines the failure of the in-cylinder pressure sensor.

### Claim 8 (depends on 7)

The failure diagnosis device of claim 7, wherein the engine controller is connected to a warning lamp provided to the automobile, and causes the warning lamp to light up when the in-cylinder pressure sensor is determined to be failed.

### Claim 9 (depends on 1)

The failure diagnosis device of claim 1, further comprising an engine control module into which a signal of one or more sensors at least including the in-cylinder pressure sensor is inputted and configured to operate the engine based on the signal of the one or more sensors,
wherein the engine control module stops a supply of fuel to the engine when a fuel cut condition is satisfied while the automobile travels, and
wherein the diagnosis module performs the failure diagnosis of the in-cylinder pressure sensor while the engine control module stops the supply of fuel to the engine.

### Claim 10 (depends on 9)

The failure diagnosis device of claim 9, further comprising an ignition plug disposed so as to face to the inside of the combustion chamber and configured to ignite a mixture gas inside the combustion chamber in response to an ignition signal of the engine control module,
wherein a portion of the mixture gas inside the combustion chamber starts combustion accompanied by flame propagation, by forcible ignition of the ignition plug, and remaining unburnt mixture gas then combusts by self-ignition,
wherein the engine control module outputs the ignition signal to the ignition plug before a target timing so that the unburnt mixture gas self-ignites at the target timing, and
wherein the engine control module estimates a timing at which the unburnt mixture gas self-ignites based on the signal of the in-cylinder pressure sensor.