摘要:
An object is to improve a NO x reduction effect by allowing an increase in the amount of exhaust gas circulated to an intake pipe and also achieve energy conservation and a CO 2 reduction by reducing a power consumption amount when NO x in exhaust gas of a diesel engine equipped with a turbocharger is removed by using an EGR system. An EGR conduit 32 that returns a part of exhaust gas e to an intake collecting pipe 13 is provided in an exhaust pipe 16 of a marine diesel engine 10A. An EGR valve 34, an EGR scrubber 36, and an EGR blower 38 are provided in the EGR conduit 32. A transmission shaft 26 of a turbocharger 20 is provided with an electric generator 40, and electric power generated by the electric generator 40 is sent to a drive motor 39 of the EGR blower 38 via a conductive wire 42 to drive the drive motor 39. An SCR catalytic converter 28 is provided in an exhaust pipe 28 on the downstream side of a turbine 22 to remove NO x in the exhaust gas e.
摘要:
An ECU provided in a dual-fuel diesel engine performs governor control in which, when the load increases to a switching load ratio, the ECU reduces the rate of increase in the supply of oil fuel compared with that before the load increases to the switching load ratio and starts supplying gas fuel after a certain delay from timing at which the load reaches the switching load ratio. Furthermore, when the load decreases to the switching load ratio, the ECU reduces the supply of oil fuel to less than that before the load decreases to the switching load ratio and stops supplying gas fuel after a certain delay from the timing at which the load reaches the switching load ratio.
摘要:
A fuel gas injection valve according to the present invention includes: a holder (22) including a first injection hole (61) through which fuel gas is injected to produce premixed fuel, and a second injection hole (62) through which fuel gas is injected to produce diffusion fuel; a first needle valve (23) that slidably reciprocates in the holder (22) along an axial direction to open and close the first injection hole (61) and the second injection hole (62); and a second needle valve (25) having a sealing face (94) on the top thereof and a through-hole (91) provided along the axial direction at the central portion in a radial direction of the second needle valve (25), the sealing face being brought into contact with a needle valve seat (93) provided in the holder (22), the first needle valve (23) being slidably inserted into the through-hole, and the second needle valve (25) reciprocating in the holder (22) along the axial direction to prevent fuel gas from circulating to the first injection hole (61) and the second injection hole (62) when the sealing face (94) is in contact with the needle valve seat (93), and to allow the fuel gas to circulate to the first injection hole (61) or the second injection hole (62) when the sealing face (94) is separated from the needle valve seat (93).
摘要:
An object is to, in a low-load operating range of a dual-fuel diesel engine or a dual-fuel diesel engine unit including a plurality of the dual-fuel diesel engines, reduce the amount of injection of oil fuel so as to make it possible to make exhaust gas less harmful and to reduce fuel cost. On a cylinder head 14, a plurality of dual-fuel injectors 24a, 24b are disposed, each of which having a gas fuel injector 26 that injects a gas fuel being a main fuel and a pilot fuel injector 28 that injects an oil fuel "o". In a low-load operating range where it is not necessary for the dual-fuel injectors 24a, 24b to inject fuel at the same time for ignition, fuel is injected alternately from the dual-fuel injectors 24a, 24b and combusted in every single combustion cycle. As a result, it is possible to halve the amount of injection of oil fuel in the low-load operating range.
摘要:
An object is to provide a two-cycle gas engine in which generation of NOx (nitrogen oxide) is suppressed by promoting premix of fuel gas with air. A two-cycle gas engine includes a cylinder 2, a cylinder head 3, a piston 4 that defines a combustion chamber "c" with a surrounding wall 2a of the cylinder 2 and the cylinder head 3, a fuel gas injector 8 configured to inject fuel gas 8a, 8b into the combustion chamber "c", an ignition unit 10 configured to ignite the fuel gas inside the combustion chamber, a scavenging port 6 configured to supply air into the combustion chamber "c" upon the piston 4 being positioned in vicinity of a bottom dead center, a fuel gas injection timing control unit 12 configured to cause the fuel gas injector 8 to inject the fuel gas 8b upon the piston 4 being positioned at 10° to 100° before top dead center in an ascending stroke and to cause the fuel gas injector 8 to inject the fuel gas 8a upon the piston 4 being positioned in vicinity of the top dead center, and an ignition timing control unit 12 configured to ignite the fuel gas inside the combustion chamber "c" by the ignition unit 10 upon the piston 4 being positioned in the vicinity of the top dead center.
摘要:
An ECU provided in a dual-fuel diesel engine performs governor control in which, when the load increases to a switching load ratio, the ECU reduces the rate of increase in the supply of oil fuel compared with that before the load increases to the switching load ratio and starts supplying gas fuel after a certain delay from timing at which the load reaches the switching load ratio. Furthermore, when the load decreases to the switching load ratio, the ECU reduces the supply of oil fuel to less than that before the load decreases to the switching load ratio and stops supplying gas fuel after a certain delay from the timing at which the load reaches the switching load ratio.
摘要:
An object is to, during operation in the single combustion mode where only an oil fuel is injected, prevent blockage of nozzle holes of gas fuel injectors so as to smoothly shift from the single combustion mode to a dual combustion mode. When shifting to the single combustion mode, an electromagnetic opening-and-closing valve V 1 is closed so as to block a gas fuel. Then, an electromagnetic opening-and-closing valve V 3 is opened so as to discharge the gas fuel remaining in a gas fuel supply path 50 to the outside of the system. Then, an electromagnetic opening-and-closing valve V 2 is opened so as to introduce a replacement gas from a replacement gas reservoir tank 44 to the gas fuel supply path 50, thereby replacing the contents inside the gas fuel supply path 50 with the replacement gas. After completing the replacement, the electromagnetic opening-and-closing valves V 2 and V 3 are closed. Next, the electromagnetic opening-and-closing valve V 2 is opened and the replacement gas is injected from the gas fuel injectors 26 to a combustion chamber "c".
摘要:
An object is to provide a two-cycle gas engine which makes it possible to suppress generation of black exhaust, PM, or NOx during a gas operation mode. The two-cycle gas engine includes a piston 4 that defines a main combustion chamber c1 with a surrounding wall 2a of a cylinder 2 and a cylinder head 3, a fuel gas injector 8 configured to inject fuel gas 8a, 8b into the main combustion chamber c1, a scavenging port 6 that supplies air into the main combustion chamber c1 upon the piston 4 being positioned in vicinity of a bottom dead center, a precombustion chamber cap 9 that defines a precombustion chamber inside thereof, the precombustion chamber communicating with the main combustion chamber c1 through nozzle holes 9b, a fuel injection timing control unit 12 configured to inject the fuel gas 8b into the main combustion chamber c1 upon the piston being positioned at 10° to 100° before top dead center in an ascending stroke and to inject the fuel gas 8a into the main combustion chamber upon the piston being positioned in the vicinity of the top dead center, and an ignition timing control unit 12 configured to ignite a mixed air of the fuel gas and the air inside the precombustion chamber upon the piston being positioned in the vicinity of the top dead center.
摘要:
In a reciprocating internal combustion engine having a turbocharger, the removal of NO X from exhaust gas with use of a SCR system is made possible without causing deterioration of transient characteristics of the reciprocating internal combustion engine. In a reciprocating marine diesel engine (10) having a turbocharger (30) arranged in an exhaust pipe (38, 44, 48), an aqueous urea solution supply unit (42) is provided in the exhaust pipe (38) upstream of a turbine (34), so that an aqueous urea solution (b) is supplied from an aqueous urea solution tank (40). The aqueous urea solution (b) is evaporated with potential heat of the exhaust gas and hydrolyzed into ammonia gas. The ammonia gas is uniformly stirred and mixed with the exhaust gas in a highly turbulent field of the turbine (34). The exhaust gas is then sent to a SCR catalyst converter (46) provided in the exhaust pipe (44) downstream of the turbocharger (30), where NO X in the exhaust gas is reduced by the ammonia gas into nitrogen and water vapor. Since the aqueous urea solution (b) is supplied to the exhaust pipe (38) upstream of the turbine (34), ammonia gas can be generated without the need of any additional heating equipment such as an auxiliary burner.