# US 10,767,612 B2 · Control device for compression-ignition engine

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- Number: US 10,767,612 B2
- Document ID: US10767612B2
- Status: Granted
- Kind: B2
- Application number: 16/167,877
- Filed: 2018-10-23
- Published: 2019-05-16
- Granted: 2020-09-08
- Earliest claimed: 2017-11-10
- Assignees: Mazda Motor Corporation
- Applicants: Mazda Motor Corporation
- Inventors: Daisuke Tanaka; Yuichiro Tsumura; Kenko Ujihara; Yuto Matsushima; Masayoshi Higashio; Hiroki Morimoto
- Web page: https://patentgrep.com/patent/US10767612B2

## CPC

- F02M 61/14: Arrangements of injectors with respect to engines; Mounting of injectors
- F02D 19/024: {by controlling fuel injectors}
- F02D 35/023: {by determining the cylinder pressure}
- F02D 41/0027: {the fuel being gaseous (non-electrical control F02D19/02)}
- F02D 41/0057: {Specific combustion modes (combustion modes per se F02D41/3017)}
- F02D 41/006: {using internal EGR (control of valve overlap for internal EGR F02D13/0261; arrangements for internal EGR F02M26/01)}
- F02D 41/3041: {with means for triggering compression ignition, e.g. spark plug}
- F02D 41/3076: {with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing}
- F02M 21/023: {Valves; Pressure or flow regulators in the fuel supply or return system}
- F02M 21/0275: {for in-cylinder direct injection, e.g. injector combined with spark plug}
- F02B 3/06: with compression ignition (compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02)
- F02B 2075/125: {Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber}
- F02D 41/402: {Multiple injections}
- F02D 2200/025: Engine noise, e.g. determined by using an acoustic sensor
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/30: Use of alternative fuels, e.g. biofuels
- Y02T 10/40: Engine management systems
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A control device for a compression-ignition (CI) engine in which partial CI combustion including spark ignition (SI) combustion performed by combusting a portion of mixture gas inside a cylinder by spark ignition followed by CI combustion performed by causing the rest of the mixture gas inside the cylinder to self-ignite is executed within a part of an engine operating range, is provided, including an EGR (exhaust gas recirculation) controller configured to change an EGR ratio, and a combustion controller configured to control the EGR controller during the partial compression-ignition combustion to switch a combustion mode between first and second modes in which the EGR ratio is higher than the first mode. After the first mode is switched to the second mode, if a condition is satisfied, the combustion controller causes the resumption to the first mode after a given period of time has elapsed from the switching.

## Claims

### Claim 1

A control device for a compression-ignition engine in which partial compression-ignition combustion including spark ignition (SI) combustion performed by combusting a portion of a mixture gas inside a cylinder by spark ignition followed by compression ignition (CI) combustion performed by causing the remaining mixture gas inside the cylinder to self-ignite is executed at least within a part of an operating range of the engine, comprising:
an EGR (exhaust gas recirculation) controller configured to change an EGR ratio that is a ratio of exhaust gas recirculated into the cylinder; and
a combustion controller configured to control the EGR controller during the partial compression-ignition combustion to switch a combustion mode between a first mode and a second mode in which the EGR ratio is higher than the first mode,
wherein after the combustion mode is switched from the first mode to the second mode, the combustion controller is configured to cause the resumption to the first mode upon first determining that both of the following are satisfied:
a noise index value has fallen below an allowable limit, and
a given period of time has elapsed from the switching to the second mode.

### Claim 2 (depends on 1)

The device of claim 1, wherein when the second mode is selected, the combustion controller controls an air-fuel ratio that is a ratio of air to fuel inside the cylinder to be more reduced than when the first mode is selected.

### Claim 3 (depends on 1)

The device of claim 1, wherein after the partial compression-ignition combustion in the first mode is started and if the noise index value has fallen below the allowable limit, the combustion controller causes the switching to the second mode, immediately after the noise index value has fallen below the allowable limit or after a shorter period of time has elapsed from the start of the first mode than the given period.

### Claim 4 (depends on 1)

The device of claim 1, wherein a target value of a given control amount including a timing of the spark ignition is determined in advance so that a combustion center of gravity of the partial compression-ignition combustion in the first mode and a combustion center of gravity of the partial compression-ignition combustion in the second mode are located at the same position when an engine speed and an engine load are the same in the first mode and the second mode.

### Claim 5 (depends on 4)

The device of claim 4, wherein, during the partial compression-ignition combustion in the first and second modes, the combustion controller corrects the control amount with respect to the target value based on the noise index value representing noise accompanying the combustion, and when the noise index value is confirmed to exceed a given threshold while the first mode is selected, switches the combustion mode from the first mode to the second mode.

### Claim 6

A control device for a compression-ignition engine in which partial compression-ignition combustion including spark ignition (SI) combustion performed by combusting a portion of a mixture gas inside a cylinder followed by compression ignition (CI) combustion performed by causing the remaining mixture gas inside the cylinder to self-ignite is executed at least within a part of an operating range of the engine, comprising:
an air-fuel ratio controller configured to change an air-fuel ratio that is a ratio of air to fuel inside the cylinder; and
a combustion controller configured to control the air-fuel ratio controller during the partial compression-ignition combustion to switch a combustion mode between a first mode and a second mode in which the air-fuel ratio is lower than the first mode,
wherein after the combustion mode is switched from the first mode to the second mode, the combustion controller is configured to cause the resumption to the first mode upon first determining that both of the following are satisfied:
a noise index value has fallen below an allowable limit, and
a given period of time has elapsed from the switching to the second mode.