# US 2019/0170077 A1 · Combustion control method and combustion control system with variable excess air coefficient for gasoline engine

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- Number: US 2019/0170077 A1
- Document ID: US20190170077A1
- Status: Published application
- Kind: A1
- Application number: 16/304,700
- Filed: 2017-09-28
- Published: 2019-06-06
- Earliest claimed: 2016-09-30
- Assignees: Guangzhou Automobile Group Co., Ltd.
- Applicants: Guangzhou Automobile Group Co., Ltd.
- Inventors: Hong CHEN; Yuhuai LI; Jujiang LIU; Wenfeng ZHAN; Sicong LIN
- Web page: https://patentgrep.com/patent/US20190170077A1

## CPC

- F02D 41/182: {for the control of a fuel injection device}
- F02D 41/0002: {Controlling intake air}
- F02D 41/0057: {Specific combustion modes (combustion modes per se F02D41/3017)}
- F02D 41/3041: {with means for triggering compression ignition, e.g. spark plug}
- F02N 11/087: {Details of the switching means in starting circuits, e.g. relays or electronic switches}
- F02P 5/045: {combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02)}
- F02D 11/105: {characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque}
- F02D 13/0269: {Controlling the valves to perform a Miller-Atkinson cycle}
- F02D 2041/001: {for engines with variable valve actuation}
- F02D 2200/0402: the parameter being determined by using a model of the engine intake or its components
- F02D 2200/0414: Air temperature
- F02N 11/00: Starting of engines by means of electric motors
- F02N 11/006: {using a plurality of electric motors}
- F02N 11/04: the motors being associated with current generators
- F02N 11/0803: {characterised by means for initiating engine start or stop (F02N11/0814 takes precedence)}
- F02N 11/0866: {comprising several power sources, e.g. battery and capacitor or two batteries}
- F02N 2011/0888: {DC/DC converters}
- Y02T 10/12: Improving ICE efficiencies
- 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)
- F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A combustion control method and a combustion control system with variable excess air coefficient for gasoline engine are provided. The combustion control method with variable excess air coefficient for gasoline engine comprises steps as follows: monitoring engine operating condition; determining current engine load condition based on the engine operating condition, wherein the engine load condition comprises part load, high load, and full load conditions; and selecting an appropriate excess air coefficient combustion mode in accordance with the current engine load condition; wherein the engine uses lean combustion mode with excess air coefficient of 1.6˜2.0 when the current engine load condition is the part load condition; the engine uses combustion mode with excess air coefficient of 1 when the current engine load condition is the high load condition; and the engine uses combustion mode with excess air coefficient of 0.8˜0.9 when the current engine load condition is the full load condition.

## Claims

### Claim 1

A combustion control method with variable excess air coefficient for gasoline engine, characterized in that, it comprises steps of:
monitoring an engine operating condition;
determining a current engine load condition based on the engine operating condition, wherein an engine load condition comprises a part load condition, a high load condition, and a full load condition; and
selecting an appropriate excess air coefficient combustion mode in accordance with the current engine load condition; wherein
a lean combustion mode of the engine with an excess air coefficient of 1.6˜2.0 is used when the current engine load condition is the part load condition;
a combustion mode of the engine with an excess air coefficient of 1 is used when the current engine load condition is the high load condition; and
a combustion mode of the engine with an excess air coefficient of 0.8˜0.9 is used when the current engine load condition is the full load condition.

### Claim 2 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, wherein the part load condition is a condition in which the engine operates at 0˜50% rated power, the high load condition is a condition in which the engine operates at 50%˜90% rated power, and the full load condition is a condition in which the engine operates at 90%˜100% rated power.

### Claim 3 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, when the current engine load condition is the part load condition, using the lean combustion mode of the engine with the excess air coefficient of 1.6˜2.0, in which combustion mode, a fuel supply amount is precisely controlled by means of a fuel injection system and an amount of intake fresh air is precisely controlled by means of a variable valve system so as to form a lean mixture with the excess air coefficient of 1.6˜2.0 inside the cylinder and ignite it, and meanwhile Miller cycle is used in combination with exhaust gas recirculation of the engine so as to lower combustion temperature inside the engine cylinder and make the combustion temperature inside the engine cylinder lower than 1900K.

### Claim 4 (depends on 3)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 3, characterized in that, controlling, by exhaust gas recirculation, a quantity and a temperature of re-circulated exhaust gas after combustion in such a manner that at the ignition timing a mixture temperature of the lean mixture inside the cylinder with the excess air coefficient of 1.6˜2.0 equals to quasi self-ignition temperature.

### Claim 5 (depends on 3)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 3, characterized in that, igniting the lean mixture with the excess air coefficient of 1.6˜2.0 by ignition energy greater than 400 MJ.

### Claim 6 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, when the current engine load condition is the high load condition, using the combustion mode of the engine with the excess air coefficient of 1, in which combustion mode, a fuel supply amount is precisely controlled by means of a fuel injection system and an amount of intake fresh air is precisely controlled by means of a variable valve system, so as to form a mixture with the excess air coefficient of 1 inside the cylinder and ignite it, and meanwhile, adjusting a quantity and a temperature of re-circulated exhaust gas by exhaust gas recirculation of the engine, so as to realize appropriate combustion.

### Claim 7 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, when the current engine load condition is the full load condition, using the combustion mode of the engine with the excess air coefficient of 0.8˜0.9, in which combustion mode, a fuel supply amount is precisely controlled by means of a fuel injection system and an amount of intake fresh air is precisely controlled by means of a variable valve system, so as to form a rich mixture with the excess air coefficient of 0.8˜0.9 inside the cylinder and ignite it, and meanwhile adjusting a quantity and a temperature of re-circulated exhaust gas by exhaust gas recirculation of the engine, so as to realize appropriate combustion.

### Claim 8 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, the combustion control method with variable excess air coefficient for gasoline engine further comprises a step of controlling a quantity of the re-circulated exhaust gas after combustion by exhaust gas recirculation, wherein quantities of the re-circulated exhaust gas under three combustion modes have a relationship as follows: the quantity in the lean combustion mode with the excess air coefficient of 1.6˜2.0>the quantity in the combustion mode with the excess air coefficient of 1>the quantity in the combustion mode with the excess air coefficient of 0.8˜0.9.

### Claim 9 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, the combustion control method with variable excess air coefficient for gasoline engine further comprises a step of controlling a temperature of the re-circulated exhaust gas after combustion by exhaust gas recirculation, wherein temperatures of the re-circulated exhaust gas under three combustion modes have a relationship as follows: the temperature in the lean combustion mode with the excess air coefficient of 1.6˜2.0>the temperature in the combustion mode with the excess air coefficient of 1>the temperature in the combustion mode with the excess air coefficient of 0.8˜0.9.

### Claim 10 (depends on 1)

The combustion control method with variable excess air coefficient for gasoline engine according to claim 1, characterized in that, after catalytic conversion of the exhaust gas to be discharged that is produced by the combustion in the engine, discharging the exhaust gas.

### Claim 11

A combustion control system with variable excess air coefficient for gasoline engine, characterized in that, it comprises a cylinder block structure, a variable valve system, a fuel injection system, a high energy ignition system, an exhaust gas recirculation system, an operating condition monitoring system, and an engine electronic control unit, wherein the cylinder block structure comprises a cylinder, the variable valve system is configured to control an amount of fresh air supplied to the cylinder, the fuel injection system is configured to control an amount of fuel injected into the cylinder, the high energy ignition system comprises a high energy spark plug and is configured for discharge ignition, and the exhaust gas recirculation system is configured to control a quantity and a temperature of re-circulated exhaust gas;
the engine electronic control unit is electrically connected with the operating condition monitoring system, the variable valve system, the fuel injection system, the high energy ignition system, and the exhaust gas recirculation system, respectively;
the operating condition monitoring system is configured to monitor an engine operating condition and transmit the monitored result to the engine electronic control unit;
the engine electronic control unit is configured to determine a current engine load condition based on the engine operating condition, wherein an engine load condition comprises a part load condition, a high load condition, or a full load condition;
the engine electronic control unit is configured to select an appropriate excess air coefficient combustion mode in accordance with the current engine load condition, wherein:
when the current engine load condition is the part load condition, the engine is controlled, by means of the engine electronic control unit, to use a lean combustion mode with an excess air coefficient of 1.6˜2.0;
when the current engine load condition is the high load condition, the engine is controlled, by means of the engine electronic control unit, to use a combustion mode with an excess air coefficient of 1;
when the current engine load condition is the full load condition, the engine is controlled, by means of the engine electronic control unit, to use a combustion mode with an excess air coefficient of 0.8˜0.9.

### Claim 12 (depends on 11)

The combustion control system with variable excess air coefficient for gasoline engine according to claim 11, characterized in that, the operating condition monitoring system comprises an engine speed monitoring sensor and a power monitoring device.

### Claim 13 (depends on 11)

The combustion control system with variable excess air coefficient for gasoline engine according to claim 11, characterized in that, the exhaust gas recirculation system comprises an exhaust gas recirculation line, an exhaust gas recirculation control valve, an exhaust gas recirculation intercooler, an exhaust gas bypass return line and a bypass waste gate, wherein the exhaust gas recirculation line has an outlet end in communication with the intake pipe, and the exhaust gas recirculation line has an inlet end in communication with the exhaust pipe, the exhaust gas recirculation control valve and the exhaust gas recirculation intercooler are arranged in the exhaust gas recirculation line in series connection, the exhaust gas bypass return line and the exhaust gas recirculation intercooler are arranged in parallel, and the bypass waste gate is arranged in the exhaust gas bypass return line.

### Claim 14 (depends on 11)

The combustion control system with variable excess air coefficient for gasoline engine according to claim 11, characterized in that, the exhaust gas recirculation system is configured to control the quantity of the re-circulated exhaust gas after combustion, wherein quantities of the re-circulated exhaust gas under three combustion modes have a relationship as follows: the quantity in the lean combustion mode with the excess air coefficient of 1.6˜2.0>the quantity in the combustion mode with the excess air coefficient of 1>the quantity in the combustion mode with the excess air coefficient of 0.8˜0.9.

### Claim 15 (depends on 11)

The combustion control system with variable excess air coefficient for gasoline engine according to claim 11, characterized in that, the exhaust gas recirculation system is configured to control the temperature of the re-circulated exhaust gas after combustion, wherein temperatures of the re-circulated exhaust gas under three combustion modes have a relationship as follows: the temperature in the lean combustion mode with the excess air coefficient of 1.6˜2.0>the temperature in the combustion mode with the excess air coefficient of 1>the temperature in the combustion mode with the excess air coefficient of 0.8˜0.9.

### Claim 16 (depends on 11)

The combustion control system with variable excess air coefficient for gasoline engine according to claim 11, characterized in that, ignition energy of the high energy spark plug is capable of igniting the rich mixture having an excess air coefficient of 0.8˜0.9 and the mixture having an excess air coefficient of 1, and is capable of igniting the lean mixture having an excess air coefficient of 1.6˜2.0.