IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0609668
(2003-07-01)
|
우선권정보 |
JP-0193548 (2002-07-02) |
§371/§102 date |
20030805
(20030805)
|
발명자
/ 주소 |
- Nishimoto, Toshiaki
- Asanomi, Kouji
- Sumida, Kouji
- Hayashi, Takayoshi
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
10 인용 특허 :
10 |
초록
▼
A control device for a multicylinder spark-ignition engine includes a flow path switching unit for switching intake and exhaust flow paths between a two-cylinder interconnect configuration and an independent cylinder configuration and an air-fuel ratio control unit. In a low-load, low-speed operatin
A control device for a multicylinder spark-ignition engine includes a flow path switching unit for switching intake and exhaust flow paths between a two-cylinder interconnect configuration and an independent cylinder configuration and an air-fuel ratio control unit. In a low-load, low-speed operating range, the flow path switching unit switches the engine to the two-cylinder interconnect configuration, and the air-fuel ratio control unit produces a lean mixture having an air-fuel ratio larger than the stoichiometric air-fuel ratio by a specific amount in preceding cylinders by injecting fuel thereinto and an air-fuel ratio approximately equal to the stoichiometric air-fuel ratio in following cylinders by supplying fuel together with burned gas of a lean mixture state discharged from the preceding cylinders into the following cylinders to perform combustion in special operation mode. At engine startup, the flow path switching unit switches the engine to the independent cylinder configuration to perform combustion in normal operation mode.
대표청구항
▼
1. A control device for a multicylinder spark-ignition engine of which individual cylinders undergo successive combustion cycles with specific phase delays, wherein the engine is switched depending on its operating conditions between a normal operation mode, in which combustion is produced with the
1. A control device for a multicylinder spark-ignition engine of which individual cylinders undergo successive combustion cycles with specific phase delays, wherein the engine is switched depending on its operating conditions between a normal operation mode, in which combustion is produced with the individual cylinders set to work independently of one another, and a special operation mode, in which burned gas discharged from a preceding cylinder which is currently in an exhaust stroke is introduced directly into a following cylinder which is currently in an intake stroke, said control device comprising:a flow path switching unit for switching intake and exhaust flow paths to form a two-cylinder interconnect configuration in the special operation mode such that the burned gas discharged from the preceding cylinder is introduced into the following cylinder through an intercylinder gas channel and an independent cylinder configuration in the normal operation mode such that fresh air is introduced into the individual cylinders; and an air-fuel ratio control unit for controlling the air-fuel ratio in the individual cylinders in such a manner that combustion in the preceding cylinder is produced under lean mixture conditions at an air-fuel ratio larger than the stoichiometric air-fuel ratio by a specific amount by injecting fuel directly into the preceding cylinder and combustion in the following cylinder is produced at an air-fuel ratio approximately equal to the stoichiometric air-fuel ratio by supplying the fuel together with the burned gas of a lean mixture state discharged from the preceding cylinder in the special operation mode; wherein said flow path switching unit switches the intake and exhaust flow paths to the independent cylinder configuration at engine startup to perform combustion control operation in the normal operation mode. 2. The control device according to claim 1, said flow path switching unit including:a switching mechanism having: an actuating member which shifts from a home position where the intake and exhaust flow paths are set to the independent cylinder configuration to an activated position where the intake and exhaust flow paths are set to the two-cylinder interconnect configuration and a biasing member for exerting a pushing force on the actuating member to return it to the home position; and a drive mechanism for causing the actuating member to shift to the activated position; wherein the actuating member is automatically returned to the home position due to the pushing force of the biasing member under normal conditions. 3. The control device according to claim 2, wherein the preceding cylinder is provided with an intake port connected to an intake passage, a first exhaust port connected to an exhaust passage, a second exhaust port connected to the intercylinder gas channel, a first exhaust valve for opening and closing the first exhaust port and a second exhaust valve for opening and closing the second exhaust port, and the following cylinder is provided with a first intake port connected to the intake passage, a second intake port connected to the intercylinder gas channel, an exhaust port connected to the exhaust passage, a first intake valve for opening and closing the first intake port and a second intake valve for opening and closing the second intake port, and wherein the switching mechanism for setting the intake and exhaust flow paths to the independent cylinder configuration by switching the first exhaust valve and the first intake valve to their activated state when an actuating member returns to the home position and by switching the second exhaust valve and the second intake valve to their closed state is provided in valve actuating mechanisms of the first and second exhaust valves and the first and second intake valves.4. The control device according to claim 3, wherein a first switching mechanism for switching the first exhaust valve and the first intake valve to their activated state when an actuating member returns to its home position is provided in a first tappet portion for transmitting driving forces of cams to the first exhaust valve and the first intake valve, and a second switching mechanism for switching the second exhaust valve and the second intake valve to their closed state when an actuating member returns to its home position is provided in a second tappet portion for transmitting driving forces of cams to the second exhaust valve and the second intake valve.5. The control device according to claim 3, wherein the switching mechanisms for switching the first exhaust valve and the first intake valve to their activated state and the second exhaust valve and the second intake valve to their closed state when actuating members return to their home positions are provided to rocker arms for transmitting driving forces of cams to the first and second exhaust valves and the first and second intake valves.6. The control device according to claim 1, wherein the preceding cylinder is provided with an intake port connected to an intake passage, a first exhaust port connected to an exhaust passage and a second exhaust port connected to the intercylinder gas channel, and the following cylinder is provided with a first intake port connected to the intake passage, a second intake port connected to the intercylinder gas channel and an exhaust port connected to the exhaust passage, said flow path switching unit including:an intake on-off valve provided in a branched channel of the intake passage connected to the first intake port of the following cylinder; an exhaust on-off valve provided in a branched channel of the exhaust passage connected to the second exhaust port of the preceding cylinder; a gas channel on-off valve provided in the intercylinder gas channel; a first biasing member for exerting a pushing force on the intake on-off valve and the exhaust on-off valve toward open positions which are their home positions under normal conditions; a second biasing member for exerting a pushing force on the gas channel on-off valve toward a closed position which is its home position; a first solenoid actuator for driving the intake on-off valve and the exhaust on-off valve toward closed positions which are their activated positions against the pushing forces exerted by the biasing members; and a second solenoid actuator for driving the gas channel on-off valve toward an open position which is its activated position. 7. The control device for the spark-ignition engine according to claim 1, wherein a three-way catalyst is provided in an exhaust passage, the preceding cylinder is provided with an intake port connected to an intake passage, a first exhaust port connected to the exhaust passage, a second exhaust port connected to the intercylinder gas channel, a first exhaust valve for opening and closing the first exhaust port and a second exhaust valve for opening and closing the second exhaust port, and the following cylinder is provided with a first intake port connected to the intake passage, a second intake port connected to the intercylinder gas channel, an exhaust port connected to the exhaust passage, a first intake valve for opening and closing the first intake port and a second intake valve for opening and closing the second intake port, said flow path switching unit including:a switching mechanism having an actuating member which shifts from a home position where the intake and exhaust flow paths are set to the independent cylinder configuration with the first exhaust valve and the first intake valve set to their activated state to an activated position where the intake and exhaust flow paths are set to the two-cylinder interconnect configuration with the first exhaust valve and the first intake valve set to their closed state, and a biasing member for exerting a pushing force on the actuating member to return it to the home position; and a drive mechanism for causing the actuating member to shift to the activated position; and wherein said flow path switching unit switches the intake and exhaust flow paths to the independent cylinder configuration by causing the actuating member to automatically return to the home position due to the pushing force of the biasing member at engine startup to perform the combustion control operation in the normal operation mode.
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