A four-cycle engine (1) structured to introduce fresh air into a cylinder (1a) via an intake port (1d) opened/closed by intake valves (IN1, IN2) and suck exhaust gas back into the cylinder (1a) via an exhaust port opened/closed by exhaust valves (EX1, EX2), wherein the exhaust port has a first exhau
A four-cycle engine (1) structured to introduce fresh air into a cylinder (1a) via an intake port (1d) opened/closed by intake valves (IN1, IN2) and suck exhaust gas back into the cylinder (1a) via an exhaust port opened/closed by exhaust valves (EX1, EX2), wherein the exhaust port has a first exhaust port (1p) and a second exhaust port (1e), and the exhaust gas is sucked in back from the first exhaust port (1p) and secondary air is sucked in from the second exhaust port (1e) to form, in the cylinder (1a), a first temperature layer (T1) at a high temperature mainly composed of the exhaust gas and a second temperature layer (T2) at a temperature lower than that of the first temperature layer (T1) mainly composed of the secondary air.
대표청구항▼
1. A four-cycle engine comprising: a first cylinder, and a second cylinder different in combustion timing from the first cylinder and structured to introduce fresh air into a cylinder via an intake port opened/closed by an intake valve and suck exhaust gas back into the cylinder via at least one of
1. A four-cycle engine comprising: a first cylinder, and a second cylinder different in combustion timing from the first cylinder and structured to introduce fresh air into a cylinder via an intake port opened/closed by an intake valve and suck exhaust gas back into the cylinder via at least one of first and second exhaust ports opened/closed by at least one exhaust valve, and includinga controller for controlling a valve opening system so that the exhaust gas is sucked through the first exhaust port and secondary air is sucked through the second exhaust port to form, in the cylinder, a first temperature layer having a high temperature containing the exhaust gas in the fresh air and a second temperature layer having a temperature lower than that of the first temperature layer containing the secondary air in the fresh air,a blowdown pressure wave supercharging system structured to cause a pressure wave from a combustion chamber at opening of the exhaust valves of the first cylinder to act on the exhaust ports of the second cylinder during a reopen period during which the exhaust valves of the second cylinder are reopened; anda secondary air supply system supplying secondary air to the second exhaust port,wherein the reopen period of the exhaust valves of the second cylinder is set from near a bottom dead center of an intake stroke to near a bottom dead center of a compression stroke of the second cylinder and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen period to introduce the exhaust gas through the first exhaust port into the second cylinder and introduce the secondary air supplied into the second exhaust port by the secondary air supply system into the second cylinder. 2. The four-cycle engine according to claim 1, wherein the secondary air supply system comprises an air pump connected to the second exhaust port via a secondary air supply path, and an open/close control valve interposed in the secondary air supply path, and supplies the secondary air to the second exhaust port during a close period of the exhaust valves, andwherein the reopen period of the exhaust valves of the second cylinder is set from near the bottom dead center of the intake stroke to near the bottom dead center of the compression stroke of the second cylinder, and the blowdown pressure wave acts on the exhaust ports of the second cylinder during the reopen period to introduce the exhaust gas from the first exhaust port into the second cylinder and introduce the secondary air supplied into the second exhaust port into the second cylinder from the second exhaust port. 3. The four-cycle engine according to claim 1, wherein the engine comprises an intake system having a supercharger driven by an electric motor or engine output interposed therein, and is structured to supply compressed fresh air at a pressure equal to or higher than an exhaust port internal pressure into the cylinders,wherein the secondary air supply system is structured to allow the compressed fresh air supplied from the intake system to flow through to the second exhaust port side to thereby supply the compressed fresh air into the second exhaust port during an EGR overlap period of the intake valve in the intake stroke and the second exhaust valve of the second exhaust port during the reopen period, andwherein the reopen period of the exhaust valves of the second cylinder is set from near the bottom dead center of the intake stroke to near the bottom dead center of the compression stroke of the second cylinder, and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen period to introduce the exhaust gas from the first exhaust port into the second cylinder and introduce the secondary air supplied into the second exhaust port into the second cylinder. 4. The four-cycle engine according to claim 1, wherein the engine is structured to supply compressed fresh air at a pressure equal to or higher than an exhaust port internal pressure into the cylinders by dynamic effects of an intake system and an exhaust system,wherein the secondary air supply system is structured to allow the compressed fresh air supplied from the intake system to flow through to the second exhaust port side to thereby supply the compressed fresh air into the second exhaust port during an EGR overlap period of the intake valve in the intake stroke and the second exhaust valve of the second exhaust port during the reopen period, andwherein the reopen period of the exhaust valves of the second cylinder is set from near the bottom dead center of the intake stroke to near the bottom dead center of the compression stroke of the second cylinder, and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen period to introduce the exhaust gas from the first exhaust port into the second cylinder and introduce the secondary air supplied into the second exhaust port into the second cylinder. 5. The four-cycle engine according to claim 3, wherein a reopen start time of the second exhaust valve is set to be earlier than a close time of the intake valve and a reopen start time of the first exhaust valve is set to be later than the reopen start time of the second exhaust valve, and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen periods of the first exhaust valve and the second exhaust valve of the second cylinder. 6. The four-cycle engine according to claim 2, wherein a combustion control is conducted by controlling a valve open period of the open/close control valve for each cylinder or each cycle. 7. The four-cycle engine according to claim 4, wherein a reopen start time of the second exhaust valve is set to be earlier than a close time of the intake valve and a reopen start time of the first exhaust valve is set to be later than the reopen start time of the second exhaust valve, and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen periods of the first exhaust valve and the second exhaust valve of the second cylinder. 8. The four-cycle engine according to claim 1, wherein a mask member to restrain flow of the sucked back exhaust gas to the intake valve side is provided on an opening on the combustion chamber side of the exhaust port. 9. The four-cycle engine according to claim 2, wherein a mask member to restrain flow of the sucked back exhaust gas to the intake valve side is provided on an opening on the combustion chamber side of the exhaust port. 10. The four-cycle engine according to claim 3, wherein a mask member to restrain flow of the sucked back exhaust gas to the intake valve side is provided on an opening on the combustion chamber side of the exhaust port. 11. The four-cycle engine according to claim 4, wherein a mask member to restrain flow of the sucked back exhaust gas to the intake valve side is provided on an opening on the combustion chamber side of the exhaust port. 12. The four-cycle engine according to claim 5, wherein a mask member to restrain flow of the sucked back exhaust gas to the intake valve side is provided on an opening on the combustion chamber side of the exhaust port. 13. The four-cycle engine according to claim 1, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 14. The four-cycle engine according to claim 2, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 15. The four-cycle engine according to claim 3, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 16. The four-cycle engine according to claim 4, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 17. The four-cycle engine according to claim 5, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 18. The four-cycle engine according to claim 6, comprising: a first fuel injection valve supplying fuel to the first temperature layer and a second fuel injection valve supplying fuel to the second temperature layer, wherein a ratio of the fuels injected from the first, second fuel injection valves is controlled. 19. A four-cycle engine structured to introduce fresh air into a cylinder via an intake port opened/closed by an intake valve and suck exhaust gas back into the cylinder via at least one of first and second exhaust ports opened/closed by at least one exhaust valve, and including a controller for controlling an EGR valve opening system so that the exhaust gas is sucked through the first exhaust port and secondary air is sucked through the second exhaust port to form, in the cylinder, a first temperature layer at a high temperature containing the exhaust gas in the fresh air and a second temperature layer having a temperature lower than that of the first temperature layer containing the secondary air in the fresh air,a first cylinder, and a second cylinder different in combustion timing from the first cylinder;a blowdown pressure wave supercharging system structured to cause a pressure wave from a combustion chamber at opening of the exhaust valves of the first cylinder to act on the exhaust ports of the second cylinder during a reopen period during which the exhaust valves of the second cylinder are reopened; anda secondary air supply system supplying secondary air to the second exhaust port,wherein the reopen period of the exhaust valves of the second cylinder is set from near a bottom dead center of an intake stroke to near a bottom dead center of a compression stroke of the second cylinder and the blowdown pressure wave from the first cylinder acts on the exhaust ports of the second cylinder during the reopen period to introduce the exhaust gas from the first exhaust port into the second cylinder and introduce the secondary air supplied into the second exhaust port by the secondary air supply system into the second cylinder.
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이 특허에 인용된 특허 (15)
Fukuda Takafumi (Iwata JPX) Ito Takeshi (Iwata JPX) Harada Keiichi (Iwata JPX), Combustion chamber for injected engine.
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