KR20240076700A - Large two-stroke uniflow scavenged internal combustion engine configured to operate with high jacket water temperature - Google Patents

Abstract

A large two-stroke uniflow scavenged internal combustion engine and method configured for operation with high jacket water temperatures. For throttling the flow of water from the wet cooling circuit 70 to the expansion tank 77 or pressure vessel 74 in case of inadvertent boiling of water in the cooling jacket, cylinder cover or exhaust valve due to stagnation in the wet cooling circuit 70. An orifice is provided at each fluid connection between the cooling circuit 70 and the expansion tank 77 or pressure vessel 74.

Description

LARGE TWO-STROKE UNIFLOW SCAVENGED INTERNAL COMBUSTION ENGINE CONFIGURED TO OPERATE WITH HIGH JACKET WATER TEMPERATURE}

The present disclosure relates to large two-stroke internal combustion engines configured to operate at high jacket water temperatures, and in particular to large two-stroke uniflow scavenged internal combustion engines with a crosshead running on fuel (gaseous or liquid fuel).

For example, large two-stroke turbocharged Uniflow scavenging internal combustion engines with crossheads are used as the main power source for propulsion of large ocean-going ships or power plants. These two-stroke diesel engines are not only larger in size but are also constructed differently from other internal combustion engines. The weight of the exhaust valve is up to 400 kg, the diameter of the piston is up to 100 cm, and the maximum operating pressure in the combustion chamber is usually several hundred bar. The forces that accompany these high pressure levels and piston sizes are enormous.

Large two-stroke turbocharged internal combustion engines operate on liquid fuels (e.g. fuel oil, marine diesel, heavy oil, ethanol, dimethyl ether (DME)) or gaseous fuels (e.g. ammonia, methane, natural gas (LNG), petroleum gas). (LPG), methanol or ethane).

Engines running on gaseous fuel may operate according to the Otto cycle in which the gaseous fuel is introduced by a fuel valve arranged centrally along the length of the cylinder cover or cylinder liner, i.e. such engines start well before the exhaust valve closes. introduces gaseous fuel during the upstroke (from BDC to TDC) of the piston and compresses the mixture of gaseous fuel and scavenge air in the combustion chamber, compressed at or near TDC by means of timed ignition, for example a liquid fuel injector. Ignite the mixture.

Engines running on liquid fuel and engines running on gaseous fuel via high-pressure injection inject gaseous or liquid fuel when the piston is at or near TDC, i.e. when the compression pressure in the combustion chamber is at or near maximum, thus creating a diesel cycle. Accordingly, it operates with compression ignition.

The fuel economy of a two-stroke turbocharged internal combustion engine is limited by Carnot's theorem (https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics)), whereby operating at higher absolute temperatures increases fuel economy. do. In known two-stroke turbocharged internal combustion engines, the cylinder liners, cylinder covers and exhaust valves are cooled by jacket water maintained at a temperature of about 80 to 90° C., which reduces the temperature of the cylinder liners, cylinder covers and exhaust valves and, indirectly, Limits the maximum temperature of the combustion chamber. Simply increasing the temperature of the jacket water in known engines is not possible because known jacket water cooling systems are not configured to handle such high temperatures, which carries the risk of the jacket water boiling and thus causing the jacket water to escape from the jacket water system. If forced quickly and there is no jacket water in the jacket water cooling system, the engine will have no forced cooling capability.

JP2015132191 discloses a large two-stroke internal combustion engine according to the preamble of claim 1.

The aim is to provide an engine and method that overcomes or at least reduces the problems mentioned above.

The above and other objects are achieved by the features of the independent claims. Additional embodiment forms become apparent from the dependent claims, description and drawings.

According to a first aspect, a large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead is provided, the engine comprising:

a plurality of combustion chambers each defined by a cylinder liner, a piston configured to reciprocate in the cylinder liner, and a cylinder cover;

a scavenge port arranged in each cylinder liner for introducing scavenge gases into the combustion chamber;

at least one cooling channel in the cylinder cover,

an annular cooling chamber surrounding a portion of each cylinder liner;

an exhaust gas outlet arranged in each cylinder cover and controlled by an exhaust valve;

the plurality of combustion chambers being connected to a scavenge gas receiver through a scavenge port and to an exhaust gas receiver through an exhaust gas outlet;

an exhaust gas system comprising a turbine of a turbocharger system driven by a flow of exhaust gases;

an air inlet system comprising a compressor of a turbocharger system, wherein the compressor is configured to supply pressurized scavenge gas to a scavenge gas receiver;

At least one primary circulation pump configured to circulate water in the primary cooling circuit, wherein at least one cooling channel in the cylinder cover and preferably also an annular cooling chamber of the plurality of combustion chambers are configured to circulate water in the primary cooling circuit. primary cooling circuit, which is part of

A pressure vessel or expansion tank connected by a fluid connection to the primary cooling circuit to allow expansion and contraction of water in the primary cooling circuit,

The fluid connection is formed by one or more conduits, each conduit comprising an orifice for throttling the flow of water from the primary cooling circuit to the pressure vessel or expansion tank.

By providing an orifice at each fluid connection between the pressure vessel or expansion tank and the primary cooling circuit, water from the primary cooling circuit into the pressure vessel or expansion tank in case the water in the cooling chamber inadvertently boils due to stagnation in the primary cooling circuit. The flow is throttled. This throttling effect (if the engine is stopped or the engine load is reduced when water in the primary cooling circuit unintentionally stagnates) causes the pressure from the primary cooling circuit to decrease sufficiently to reduce the temperature of the cooling chamber by passive cooling. It slows the discharge of water into the vessel or expansion tank and thus prevents the primary cooling circuit from emptying of the water, thereby allowing rapid restart of normal engine operation when the circulating capacity of the primary cooling circuit is re-established.

In a possible implementation of the first aspect, the orifice reduces the cross-sectional area available for flow by a factor of at least 50, preferably by a factor of at least 100 and most preferably by a factor of at least 150 for one or more conduits forming the fluid connection.

In a possible implementation of the first aspect, the orifice reduces the cross-sectional area available for flow by a factor of 75 to 250.

In a possible implementation of the first aspect, the one or more conduits have a substantially constant internal diameter between 35 mm and 80 mm, and the at least one orifice has a minimum diameter between 3 and 5 mm.

In a possible implementation of the first aspect, the engine preferably has one of the at least one orifices in parallel with one of the at least one orifices to allow water to flow from the pressure vessel or expansion tank into the primary cooling circuit when the water contracts in the cooling circuit. The fluid connection preferably includes a first non-return valve in the supply conduit fluidly connecting the pressure vessel or expansion tank to the deaerator.

In a possible implementation of the first aspect, the engine preferably stores water in a pressure vessel or expansion tank from the primary cooling circuit when the pressure of the water in the primary cooling circuit rises above a threshold due to the expansion of the water in the primary cooling circuit. and a pressure setting valve in a supply conduit fluidly connecting the pressure vessel or expansion tank to the fluidic connection, preferably to the deaerator, in parallel with one of the at least one orifices to allow flow to the deaerator.

In a possible implementation of the first aspect, the engine preferably has a pressure vessel or expansion tank in the fluid connection, preferably in the de-aerator, in parallel with one of the at least one orifices, for initially filling the cooling circuit with water. A first control valve is included in the fluidically connecting supply conduit.

In a possible implementation of the first aspect, the engine may:

- Engine coolant inlet and engine coolant outlet,

- a primary circulation conduit extending from the engine coolant outlet to the engine coolant inlet, and

- a deaerator arranged in the circulation conduit and connected to the pressure vessel or expansion tank by a supply conduit comprising an orifice and a first vent conduit comprising an orifice, and

- preferably comprising a second vent conduit connecting the engine water outlet to a pressure vessel or expansion tank and comprising an orifice.

In a possible implementation of the first aspect, an orifice is arranged in the primary circulation conduit at a position upstream of the deaerator, and a second control valve is arranged in parallel with the orifice.

In a possible implementation of the first aspect, at least one primary circulation pump is arranged upstream of the deaerator.

In a possible implementation of the first aspect, the engine comprises a cooler for cooling the water of the primary cooling circuit, the cooler preferably arranged in parallel with a cooler limiter arranged in the primary circulation conduit and the cooler preferably comprising: It is connected to the circulation circuit by a third valve and the third control valve is preferably controlled by a controller.

In a possible implementation of the first aspect, the engine comprises a controller that receives a first signal indicative of the temperature of the water in the cooling circuit, preferably close to the position where the water leaves the engine and enters the primary circulation conduit,

The controller is configured to control the temperature of the water in the primary cooling circuit to a temperature of at least 100°C, preferably between 120 and 130°C.

In a possible implementation of the first aspect, the engine is controlled by a controller and applies a selective amount of cooling to the water in the primary cooling circuit under the control of the controller to adjust the amount of cooling applied to the water in the primary cooling circuit to a temperature of at least 100. and a cooler configured to control the temperature of the water in the primary cooling circuit to a temperature of 120 to 130 ℃.

In a possible implementation of the first aspect, the engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load, and the controller is configured to operate for the maximum engine load, and preferably for the entire range between the minimum engine load and the maximum engine load. It is arranged to control the temperature of the water in the primary cooling circuit to a temperature above 100° C. for the engine load range, preferably close to the position where the water leaves the engine and enters the primary circulation conduit.

In a possible implementation of the first aspect, the engine is configured to operate with a pressure of at least 3 barg in the primary cooling circuit.

In a possible implementation of the first aspect, the secondary cooling circuit is connected to a pressure vessel or expansion tank to regulate the pressure of the water in the primary cooling circuit and to allow expansion and contraction of the water in the primary cooling circuit.

In a possible implementation of the first aspect, the primary cooling circuit includes a first portion internal to the engine and a second portion external to the engine, the first portion extending from the engine inlet to the engine outlet, and the first portion cooling. chamber, and preferably at least one channel in the cylinder cover and preferably at least one channel and/or chamber in the housing of the exhaust valve.

In a possible implementation of the first aspect, the second part comprises a circulation conduit, the circulation conduit comprising at least one primary circulation pump, a de-aerator upstream of the at least one primary circulation pump, and preferably a de-aerator. Includes an upstream cooling device.

In a possible implementation of the first aspect, the engine includes an annular water jacket surrounding at least a portion of the cylinder liner and defining an annular cooling chamber with a radially outer side of the cylinder liner.

According to a second aspect, a large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead is provided, the engine comprising:

a plurality of combustion chambers each defined by a cylinder liner, a piston configured to reciprocate in the cylinder liner, and a cylinder cover;

at least one cooling channel in the cylinder cover,

a scavenging port arranged in each cylinder liner for introducing scavenging gas into at least one combustion chamber;

an annular cooling chamber surrounding a portion of each cylinder liner;

an exhaust gas outlet arranged in each cylinder cover and controlled by an exhaust valve;

the plurality of combustion chambers being connected to a scavenge gas receiver through a scavenge port and to an exhaust gas receiver through an exhaust gas outlet;

an exhaust gas system comprising a turbine of a turbocharger system driven by a flow of exhaust gases;

an air inlet system comprising a compressor of a turbocharger system, wherein the compressor is configured to supply pressurized scavenge gas to a scavenge gas receiver;

a secondary circulation pump configured to circulate water in the secondary cooling circuit, wherein at least one cooling channel in the cylinder cover and preferably also the cooling chambers of the plurality of combustion chambers are part of the secondary cooling circuit. Circuit,

a secondary cooling circuit fluidly connected to the primary cooling circuit by a valve system for mixing water from the primary cooling circuit with water in the secondary cooling circuit;

the primary cooling circuit comprising at least one primary circulation pump for circulating water in the primary cooling circuit;

a controller for receiving a first signal representing the temperature of the water in the secondary circuit and receiving a second signal representing the temperature of the water in the primary cooling circuit;

The controller preferably controls the valve system to adjust the amount of water from the primary cooling circuit mixed into the water in the secondary cooling circuit, thereby controlling the temperature of the water in the primary cooling circuit to a temperature below 95°C and above 100°C. It includes being configured to control the temperature of the water in the secondary cooling circuit to a temperature of, preferably, a temperature of 120°C to 140°C.

By providing a secondary cooling system comprising an annular cooling chamber in the cylinder and operating the secondary cooling system at temperatures exceeding 100° C., the fuel efficiency of the engine can be increased as explained above with reference to Carnot's theorem while 1 The secondary cooling system may be configured in the same or similar manner as a conventional primary cooling system, which typically operates at a temperature of 80 to 90° C. Therefore, only the secondary cooling system and associated components need to be suitable for operation at higher temperatures.

In a possible implementation of the second aspect, the engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load, and the controller is configured to operate the engine for the maximum engine load, and preferably between the intermediate engine load and the maximum engine load. It is arranged to control the temperature of the water in the secondary cooling circuit to a temperature above 100° C. for the load, and more preferably for the engine load between the minimum engine load and the maximum engine load.

In a possible implementation of the second aspect, the valve system comprises a fourth control valve, preferably a three-way control valve controlled by a controller, the fourth control valve being arranged in the primary cooling circuit and providing secondary cooling via a return conduit. Fluidically connected to the cooling circuit, the fourth control valve is configured to diverge a controllable amount of water flow from the secondary cooling circuit through a return conduit.

In a possible implementation of the second aspect, the engine comprises a supply conduit connecting the secondary cooling circuit to the primary cooling circuit, preferably upstream of the fourth control valve.

In a possible implementation of the second aspect, the valve system comprises a second checkpoint arranged in the secondary cooling circuit, preferably between the position at which the return conduit is connected to the secondary cooling circuit and the position at which the supply conduit is connected to the secondary cooling circuit. Includes valves.

In a possible implementation of the second aspect, the engine includes a cooler for cooling the water in the secondary cooling circuit.

In a possible implementation of the second aspect, the engine is provided with a pressure vessel arranged in the primary cooling circuit conduit and configured to regulate the water pressure in the primary and secondary cooling circuits and to allow expansion and contraction of water in the primary and secondary cooling circuits; or and a de-aerator connected to an expansion tank, the pressure vessel or expansion tank preferably having sufficient pressure to prevent the water in the secondary cooling circuit from boiling for water temperatures of up to 140°C, preferably up to 130°C. It is configured to maintain.

According to a third aspect, a method is provided for operating a large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead, the engine comprising:

a plurality of combustion chambers each defined by a cylinder liner, a piston configured to reciprocate in the cylinder liner, and a cylinder cover;

at least one cooling channel in the cylinder cover,

a scavenging port arranged in each cylinder liner for introducing scavenging gas into at least one combustion chamber;

an annular cooling chamber surrounding a portion of each cylinder liner;

an exhaust gas outlet arranged in each cylinder cover and controlled by an exhaust valve;

the plurality of combustion chambers being connected to a scavenge gas receiver through a scavenge port and to an exhaust gas receiver through an exhaust gas outlet;

an exhaust gas system comprising a turbine of a turbocharger system driven by a flow of exhaust gases;

an air inlet system comprising a compressor of a turbocharger system, wherein the compressor is configured to supply pressurized scavenge gas to a scavenge gas receiver;

a secondary circulation pump configured to circulate water in the secondary cooling circuit, wherein at least one cooling channel in the cylinder cover and preferably also the cooling chambers of the plurality of combustion chambers are part of the secondary cooling circuit. Circuit,

the primary cooling circuit being fluidly connected to the primary cooling circuit by a valve system for mixing water from the primary cooling circuit with water from the secondary cooling circuit;

the primary cooling circuit comprising at least one primary circulation pump for circulating water in the primary cooling circuit,

detecting the temperature of water in the secondary circuit;

detecting the temperature of water in the primary cooling circuit;

controlling the temperature of the water in the primary cooling circuit to a temperature below 95°C, and

and controlling the temperature of the water in the secondary cooling circuit to a temperature above 100°C, preferably between 120°C and 140°C.

In a possible implementation of the third aspect, the engine is configured to operate in an engine load range between the minimum engine load and the maximum engine load, at least for the maximum engine load, and preferably between the intermediate engine load and the maximum engine load. and more preferably for engine loads between the minimum and maximum engine loads, controlling the temperature of the water in the secondary circuit to a temperature above 100° C., preferably at a temperature between 120 and 140° C. do.

In a possible implementation of the third aspect, the method may comprise controlling the temperature of the water in the secondary cooling circuit comprising controlling the amount of water from the primary cooling circuit that is mixed into the water in the secondary cooling circuit by controlling a valve system. includes includes.

In a possible implementation of the third aspect, the method includes maintaining a pressure of at least 5 barg in the primary and secondary cooling circuits.

These and other aspects will become clear from the examples described below.

In the following detailed portions of the present disclosure, aspects, embodiments and implementations will be described in greater detail with reference to example embodiments shown in the drawings.

Figure 1 is a perspective view of a large two-stroke diesel engine.
Figure 2 is a perspective view from another angle of the large two-stroke engine of Figure 1;
Figure 3 is a schematic diagram of a large two-stroke engine according to Figures 1 and 2;
Figure 4 is a schematic diagram of a first embodiment of the engine of Figures 1 to 3;
Figure 5 is a schematic diagram of a second embodiment of the engine of Figures 1 to 3;
Figure 6 is a schematic diagram of a third embodiment of the engine of Figures 1 to 3;

In the following detailed description, internal combustion engines will be described with reference to a large two-stroke, low-speed, turbocharged internal combustion crosshead engine as an example embodiment. 1, 2 and 3 show an embodiment of a large, low-speed turbocharged two-stroke diesel engine with a crankshaft (8) and a crosshead (9). Figures 1 and 2 are perspective views seen from different angles. Figure 3 is a schematic diagram of an embodiment of the large, low-speed turbocharged two-stroke diesel engine of Figures 1 and 2 with intake and exhaust systems. In this embodiment the engine has six cylinders in a row. However, a large low-speed turbocharged two-stroke internal combustion engine may have 4 to 14 cylinders in line, with cylinder liners provided by the engine frame 11. The engine can be used, for example, as the main engine of a marine vessel or as a stationary engine to run a generator in a power plant. The total output of the engine may be, for example, 1,000 to 110,000 kW.

In this example embodiment the engine is a two-stroke uniflow scavenge engine with a scavenge port (18) in the lower region of the cylinder liner (1) and a central exhaust valve (4) in the cylinder cover (22) at the top of the cylinder liner (1). It is an expression type engine. Scavenging gas passes from the scavenging gas receiver (2) through the scavenging port (18) of the individual cylinder liner (1) when the piston (10) is below the scavenging port (18).

When the engine is operated as a premix engine (Otto principle), the gaseous fuel (e.g. methanol, petroleum gas or LPG, methane, natural gas LNG or ethane) is released as the piston 10 moves upward (from BDC to TDC). , and flows in from the gaseous fuel inlet valve 50' under the control of the electronic controller 100 before the piston 10 passes through the fuel valve 50' (gas inlet valve). Gaseous or liquid fuel (eg fuel oil) is injected at high pressure (preferably above 300 bar) and into the combustion chamber fuel valve 50 when the piston 10 is at or near TDC. The fuel gas is introduced at relatively low pressure, less than 30 bar, preferably less than 25 bar, more preferably less than 20 bar, and is supplied by the gaseous fuel supply system 30'. A flow containing fuel for injection through the fuel valve 50 is supplied by the fuel system 30 . The high pressure can be generated by the fuel system 30 (common rail) or in the fuel valve 50. The fuel inlet valves 50' are distributed around the circumference of the cylinder liner, preferably evenly, and are arranged in a central region of the length of the cylinder liner 1. The inflow of gaseous fuel occurs when the compression pressure is relatively low, i.e. much lower than the compression pressure when the piston reaches TDC, thus allowing inflow at relatively low pressure.

When the engine is operated as a compression ignition engine (diesel principle), there is no gas inlet valve 50' and when the piston 10 is at or near TDC, fuel (gaseous or liquid) flows under high pressure through the fuel valve 50. is sprayed as

The piston 10 of the cylinder liner 1 compresses a charge of gaseous fuel and scavenge gas (or compresses the scavenge gas if operated with fuel injection only at TDC) and ignition at or near TDC preferably occurs in the cylinder. It is triggered by injection of high-pressure fuel from a fuel valve 50 arranged in the cover 22 or through compression in the case of liquid fuel injection only at or near TDC. This causes combustion and produces exhaust gas containing it.

When the exhaust valve (4) is opened, the combustion gases flow through the combustion gas duct associated with the cylinder (1) to the combustion/exhaust gas receiver (3) and continue to the selective catalytic reactor ( It flows through a first exhaust gas conduit (19) comprising 33).

Via the shaft, the turbine (6) drives the compressor (7), which is supplied with fresh air through the air inlet (12). The compressor (7) delivers pressurized scavenge air to the scavenge air conduit (13) leading to the scavenge air receiver (2). The scavenge air in conduit 13 passes through an intercooler 14 to cool the scavenge air.

Upstream (shown) or downstream (not shown) of intercooler 14 an exhaust gas recirculation conduit 35 is connected to a scavenge air conduit 13 . In this position, the recirculated exhaust gas mixes with the scavenge air to form scavenge air that flows to the scavenge air receiver 2. The controller 100 (electronic control unit) is configured to adjust the ratio between scavenge air and exhaust gas in the scavenge gas, as described in more detail below.

The cooled scavenge air or gas is supplied by an electric motor ( It passes through the auxiliary blower (16) driven by 17). At higher engine loads the turbocharger compressor (7) delivers sufficient compressed scavenging air and the auxiliary blower (16) is bypassed via the non-return valve (15). This review may include one or more turbochargers (5) to form a turbocharger system.

The controller 100, which may consist of several interconnected electronic units including a processor and other hardware to perform the functions of the controller, generally controls the operation of the engine and controls, for example, gaseous fuel intake (amount and timing), liquid Controls are exerted over fuel injection (quantity and timing), opening and closing of the exhaust valve (4) (timing and degree of lift), recirculated exhaust gas rates and operation of various coolers, pumps and other equipment. Accordingly, the controller 100 detects the operating status of the engine from sensors (engine load, engine speed, blower speed, scavenge gas temperature, exhaust gas temperature at various points, exhaust gas temperature at various points, scavenge system, combustion chamber, It receives various signals that inform it of the pressure in the exhaust gas system and (if present) the exhaust gas recirculation system. Preferably the engine includes a variable timing exhaust valve actuation system allowing individual control of exhaust valve timing for each combustion chamber. The controller 100 detects the angles of the fuel valve 50, the liquid fuel inlet valve 50', the exhaust valve actuator, and the crankshaft via a signal line or wireless connection and the angular position to generate a signal indicative of the position of the crankshaft. It is connected to a sensor and preferably to a pressure sensor in the cylinder cover 22 or alternatively to a pressure sensor in the cylinder liner 1 which generates a signal indicative of the pressure in the combustion chamber.

Depending on the engine size, the cylinder liners 1 can be manufactured in various sizes, with cylinder bores generally from 250 mm to 1000 mm and corresponding typical lengths from 1000 mm to 4500 mm.

The cylinder liners 1 are mounted on a cylinder frame 23 with a cylinder cover 22 disposed on top of each cylinder liner 1 with an airtight interface therebetween. At least one cooling channel is provided in the cylinder cover 22 for cooling the cylinder cover 22, wherein at least one channel of each cylinder cover 22 is connected to the wet cooling system 60, 70, which will be described in detail below. fluid connection. The piston 10 is arranged to reciprocate between bottom dead center (BDC) and top dead center (TDC). These two extreme positions of the piston 10 are separated by 180 degrees of rotation of the crankshaft 8. The cylinder liner (1) provides a supply of cylinder lubricant when the piston (10) passes through the cylinder lubrication hole (25), after which a piston ring (not shown) in the piston (10) transfers the cylinder lubricant to the cylinder liner ( 1) A plurality of circumferentially distributed cylinder lubrication holes are provided, which are connected to a cylinder lubrication line that distributes to the working surface (inner surface) of the cylinder. The cylinder liner is provided with a jacket (not shown) and the jacket coolant circulates in the space between the jacket and the cylinder liner.

Liquid fuel valves 50 (typically one or more, preferably three or four per cylinder) are mounted on the cylinder cover 22 and connected to a source 30 of pressurized fuel. The liquid fuel valves 50 are preferably evenly distributed circumferentially around the exhaust valve 4, especially around the central outlet (opening) in the cylinder cover 22. The central outline is controlled by the exhaust valve (4). The timing and amount of apparition fuel injection are controlled by the controller 100. The fuel valve 50 is only used to inject a small amount of ignition liquid (pilot) when the engine is operating in premix mode. When the engine operates in compression ignition mode, the amount of liquid fuel required to operate the engine at the actual engine load is injected through the liquid fuel valve 50. The cylinder cover 22 may be provided with a prechamber (not shown), and the tip of the liquid fuel valve 50, generally a tip provided with a nozzle having one or more nozzle holes, allows pilot oil (ignition liquid) to be injected into the prechamber. and is arranged to be sprayed to trigger ignition. The prechamber helps ensure stable ignition.

The fuel inlet valve 50' is installed in the cylinder liner 1 (or cylinder cover 22), and its nozzle is substantially flush with the inner surface of the cylinder liner 1 and is located at the center of the fuel valve 50'. The rear end protrudes from the outer wall of the cylinder liner 22. Typically one or two, but possibly as many as three or four fuel valves 50' are provided in each cylinder liner 1 and distributed circumferentially around the cylinder liner 1 (preferably around the circumference). distributed evenly in each direction. The fuel inlet valve 50' is arranged substantially centrally along the length of the cylinder liner 1 in the embodiment. The fuel inlet valve 50' is connected to a pressurized source of gaseous fuel 30' (e.g. methanol, LPG, LNG, ethane or ammonia), i.e. the fuel is gaseous when delivered to the fuel inlet valve 50'. It is in a state. Since gaseous fuel is introduced during the stroke of the piston (10) from BDC to TDC, the pressure of the source of gaseous fuel need only be higher than the pressure present in the cylinder liner (1), and generally a pressure of less than 20 bar is required to open the fuel inlet valve. (50') is sufficient for the gaseous fuel delivered. Fuel inlet valve 50' is connected to a controller 100 that determines the timing of opening and closing of fuel inlet valve 50' and the duration of opening of fuel inlet valve 50'.

The liquid fuel for ignition is in embodiments fuel oil, marine diesel, heavy oil, ethanol or dimethyl ether (DME).

The aircraft operating mode may be one of several operating modes of the engine. Other modes may include a liquid fuel operation mode in which all fuel required for operation of the engine is provided in liquid form through the liquid fuel valve 50. In the gaseous fuel mode of operation, the engine operates with gaseous fuel as the main fuel, i.e. the one that provides most of the energy supplied to the engine, which enters the engine at relatively low pressure during the stroke of the piston from BDC to TDC, while liquid fuel provides It constitutes a relatively small amount of fuel that makes only a relatively small contribution to the amount of energy supplied, and its purpose is for just-in-time ignition, i.e. the liquid fuel acts as an ignition liquid.

Accordingly, the engine of this embodiment may be a dual fuel engine, that is, the engine has a mode in which it operates only with liquid fuel and a mode in which it operates almost exclusively with gaseous fuel.

In this embodiment the engine is shown as a premix engine operating according to the Otto principle. However, the engine may also be a compression ignition engine (operating on diesel principles) in which fuel (gas or liquid) is injected at high pressure when the piston 10 is at or near TDC.

An engine operates by supplying fuel (liquid and/or gaseous fuel) to a combustion chamber and burning the fuel in the combustion chamber to produce a stream of exhaust gases. In an embodiment not shown, a first part of the flow of exhaust gases (or combustion gases in the case of embodiments in which the recirculated gases are taken directly from the combustion chamber) is recirculated, and the other (second) part of the flow of exhaust gases as exhaust gases. is exhausted.

Downstream of the turbine 6 of the turbocharger 5 the exhaust gases generally enter a second exhaust conduit 28 which leads the exhaust gases to a boiler 20 (also known as an economizer) configured to produce steam. Steam is used, for example, on marine vessels equipped with engines for various purposes. Downstream of the boiler 20 a second exhaust conduit 28 extends to the atmosphere.

The cylinder liner (1) is provided with a jacket (21) defining an annular cooling chamber (23). The annular cooling chamber 23 is preferably arranged in the thermally most loaded upper part of the cylinder liner 1 . The annular cooling chamber 23 is fluidly connected to wet cooling systems 60, 70, which will be described in more detail below. Typically, the cylinder cover 22 and the housing for the exhaust valve 4 are provided with channels and chambers for receiving coolant from the wet cooling system.

Figure 4 shows a first embodiment of an engine with a wet cooling system shown schematically. The wet cooling system in this embodiment includes a primary cooling circuit (70) and a secondary cooling circuit (60). The primary cooling circuit 70 includes a primary circulation conduit 73 that is filled with water during engine operation. The primary circulation conduit 73 includes a primary circulation pump 72 that serves to circulate water in the primary circulation circuit 73. Two or more primary circulation pumps 72 are provided for redundancy. A non-return valve is provided downstream of each primary circulation pump 72. A first temperature sensor 75 is provided upstream of the check valve. Upstream of the primary circulation pump 72, a deaerator (deaeration vessel) 78 is arranged to remove air, gas, or steam accumulated in the water and to remove trapped air bubbles. De-aerator 78 is connected to pressure vessel 74 or expansion tank 77 via supply and vent lines. The function of the pressure vessel 74 expansion tank 77 is to store water, provide pressure to the wet cooling system, and allow expansion and contraction of the water in the wet cooling system as the water temperature changes.

Typically, a cooling device is provided upstream of the deaerator 78, including a cooler 79, for example a heat exchanger for exchanging heat with sea water if the engine is installed on a ship, or another cooling medium. The cooler 79 is fluidly connected to the primary circulation conduit 73 by a third control valve 71, for example a three-way control valve, which controls the cooler for that portion of the flow bypassing the cooler 79. A restriction to the flow approximately equal to that of the cooler 79 so that varying the size of the portion of water flowing through 79 does not materially affect the flow conditions, i.e. the resistance experienced by the primary circulation pump 72. It is arranged in parallel with an orifice (not shown in FIG. 4, shown as orifice 83 in FIGS. 5 and 6). The third control valve 71 is controlled by the controller 100 and regulates the temperature of the water in the primary cooling circuit 70 by adjusting the ratio of water passing through the cooler 79 and water bypassing the cooler 79. Adjust cooling performance to Accordingly, the controller 100 receives a signal indicating the temperature of the coolant from the first temperature sensor 75, and the controller 100 sets the temperature of the water in the primary cooling circuit 70 to a target temperature of 85°C, e.g. For example, it is adjusted to a temperature of 80 to 90°C, preferably less than 90°C. The primary circulation conduit 73 is coupled to the engine by an engine water inlet 41 and an engine water outlet 42, for example by a flange.

A fourth control valve (56), e.g. a three-way valve, is connected to the primary circulation circuit (73) downstream of the primary circulation pump (72) and the associated non-return valve, preferably at the engine outlet (42) to the engine inlet ( 41) is arranged in the part of the primary circulation conduit 73 extending therebetween. The fourth control valve 56 is connected to a return conduit 82 which is connected to the secondary circulation conduit 63 of the secondary circulation circuit 60 . The secondary circulation conduit 63 includes a secondary non-return valve 57 and a return conduit 82 is connected to the secondary circulation conduit 60 upstream of the secondary non-return valve 57 . The supply conduit (81) is connected to the primary circulation conduit (73) upstream of the fourth control valve (56) and to the secondary circulation conduit (63) at a location downstream of the secondary check valve (57).

The pressure vessel 74 expansion tank 77 together with the primary circulation pump 72 ensures that the water in the primary and secondary cooling circuits 60, 70 is supplied for a water temperature of up to 140°C, preferably up to 130°C. It is configured to maintain a pressure sufficient to prevent boiling, i.e. to maintain the water pressure in the primary cooling circuit to be at least 3 barg, preferably at least 4 barg and most preferably at least 5 barg.

The fourth control valve 56 is controlled by the controller 100 and regulates the ratio between the water supplied to the secondary circulation conduit 63 and the water bypassing the secondary circulation conduit 63 to form a secondary cooling circuit. The amount of water in the primary circulation conduit (73) mixed with the water in the secondary circulation circuit (63) is adjusted relative to the water temperature of (60). Accordingly, the controller 100 receives a signal indicating the temperature of the coolant in the secondary circulation circuit 63 from the second temperature sensor 65, and the controller 100 receives the temperature of the water in the secondary cooling circuit 60, for example. For example, it is configured to adjust the temperature to a temperature exceeding 100°C, preferably 120 to 140°C. The secondary circulation pump 62 ensures the circulation of water in the circulation circuit 63. Provision is made to bypass the secondary circulation pump 62 so that the secondary circulation pump 62 can be bypassed when necessary.

The fourth control valve 56 is preferably a three-way control valve controlled by the controller 100, the fourth control valve 56 being arranged in the primary cooling circuit 70 and via the supply conduit 82. Fluidically connected to the secondary cooling circuit 60, the fourth control valve 56 diverges a controllable amount of water flow to the secondary cooling circuit 60 through the supply conduit 82, thereby forming the secondary cooling circuit. It is configured to branch a flow of water of the same size from (60) to the primary cooling circuit (70).

The cooling circuit 60 passes through the annular cooling chamber 23 of all cylinder liners 1 and the cylinder cover 22 and, optionally, also through the housing of the exhaust valve 4, (2), and optionally also for the housing of the exhaust valve 4 to operate at increased temperatures (increased compared to known large two-stroke internal combustion engines operating with coolant in a cooling chamber having a temperature of 80 to 90° C.). This improves fuel efficiency.

The dashed rectangles in Figure 4 represent all components that are considered part of the actual engine, while the remaining components are considered part of the wet cooling system, i.e. the auxiliary system.

Figure 5 shows a second embodiment of the engine. In this embodiment, structures and features that are the same or similar to corresponding structures and features previously described or shown are denoted by the same reference numerals as previously used for simplicity. Since the engine and its operation in this embodiment are almost identical to the previous embodiment, only the differences from the previous embodiment will be described in detail.

This embodiment comprises a primary cooling circuit (70) connected to the engine by an engine water inlet (41) and an engine water outlet (42), with a portion of the cooling circuit flowing through the engine, in particular through the cooling chamber (23). It extends through the cylinder cover 22 and the housing of the exhaust valve 4, optionally also for cooling these components. In this embodiment, the expansion tank 77 serves to ensure static pressure, and is a storage tank to allow expansion and contraction of the water in the primary cooling circuit 70 due to fluctuations in the temperature of the water in the primary cooling circuit 70. form

The expansion tank 77, together with the primary circulation pump 72, maintains sufficient pressure to prevent the water in the primary cooling circuit 70 from boiling for water temperatures of up to 140°C, preferably up to 130°C. It is configured to maintain the water pressure in the primary cooling circuit at least 3 barg, preferably at least 4 barg and most preferably at least 5 barg.

A supply conduit (89) is connected to the expansion tank (77) to provide a resupply of water and is vented to keep the pressure in the expansion tank constant by allowing air above the surface of the water in the expansion tank (77) to connect to the atmosphere. (90) is provided. In an embodiment a level sensor is provided to monitor the water level in the expansion tank 77. Therefore, during normal operation the expansion tank 77 is always partially filled with water.

The cooler 79 and the associated third control valve 71 and orifice 83 are arranged upstream of the deaerator, and the third control valve 71 is operated under the control of the controller 100.

Although three primary circulation pumps 72 are shown in this embodiment, it should be understood that the primary cooling circuit may cooperate with two or more circulation pumps to provide a sufficient level of redundancy. The deaeration vessel 78 is connected by a first vent conduit 85 to allow air, gas or steam removed from the water in the primary cooling circuit 72 to escape the expansion tank 77 to the atmosphere that fired it. It is connected to the expansion tank (77). The de-aeration vessel 78 is also connected to the expansion vessel 77 by a supply conduit 84, which communicates the water pressure and exchanges water volumes between the primary circulation circuit 73 and the expansion tank 77. Forms the main fluid connection for A second discharge conduit (87) connects the engine water outlet (42) directly to the expansion tank (77). Accordingly, in this embodiment there are three conduits 84, 85, 87 connecting the expansion tank 77 to the primary circulation circuit 73. Each of these three conduits 84, 85, 87 is provided with an orifice 87, 88, 93 for throttling the flow of water from the primary circulation conduit 73 to the expansion tank 77. In case of stagnation of water in (73), this means that in the engine, especially in the cooling chamber (23) and through the cylinder cover (22), and in particular the cylinder liner (1) and cylinder cover (22) are relatively hot. When the engine is operated at high or full load, this can lead to water loading of part of the circuit 73. In this situation it is advantageous for the boiling water not to discharge all the water from the primary circulation conduit 73 into the expansion tank 77 and possibly from the expansion tank 77 into the atmosphere. This is achieved by the throttling effect of the orifices 78, 88, 93 which slows down the flow of water towards the expansion tank 77, thereby providing pressure for the cylinder liner 1 (and cylinder cover 22 and exhaust valve 4). housing) to passively cool, so that most or all of the water in the primary circulation conduit 73 is retained in the primary circulation conduit 73. The piping forming the supply conduit 84, first vent conduit 85 and second vent conduit 87 generally has a substantially constant internal diameter of 35 mm to 80 mm, and the orifice is preferably 3 to 5 mm. It has a minimum diameter of mm. Preferably orifices 87, 88, 93 reduce the cross-sectional area available for flow by at least 50 times, preferably at least 100 times, and most preferably at least 150 times compared to conduits 84, 85, 87.

In one embodiment the first non-return valve 91 is arranged in the supply conduit 84 in parallel with the orifice 93 to ensure rapid filling of water from the expansion tank 77 into the circulation conduit 73 when the water contracts. do.

In one embodiment, a pressure setting valve 92 is arranged in the supply conduit 84 in parallel with the orifice 93, preferably to allow expansion of the water in the primary cooling circuit 70 to reduce pressure in the primary cooling circuit 70. When the water pressure rises above the threshold (the pressure threshold is set by the opening pressure of the pressure setting valve), water is allowed to flow from the primary cooling conduit 73 into the pressure vessel 74 or expansion tank 77. .

In an embodiment the first control valve 94 is arranged in the supply conduit 84 in parallel with the orifice 93 for initially charging the cooling circuit 70 with water.

In an embodiment, the controller receives a first signal indicating the temperature of the water in the cooling circuit, preferably close to the location where the water leaves the engine and enters the primary circulation conduit, and the controller 100 controls the primary cooling circuit 70 It is configured to control the water temperature to a temperature of at least 100°C, preferably 120 to 130°C. The cooler 79 is controlled by the controller 100, and applies a selective cooling amount to the water in the primary cooling circuit 70 under the control of the controller 100 to cool the water in the primary cooling circuit 70. It is configured to control the temperature of the water in the primary cooling circuit 70 to at least 100°C, preferably 120 to 130°C, by adjusting the cooling amount.

The engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load (maximum continuous rating), and the controller 100 is configured to operate at least for the maximum engine load, preferably for the entire range between the minimum engine load and the maximum engine load. It is configured to control the temperature of the water in the primary cooling circuit (70) close to the position where the water leaves the engine and enters the primary circulation conduit (73) to a temperature above 100°C for the engine load range.

Although the embodiment of Figure 5 is disclosed using an expansion tank 77, it is understood that this embodiment will function equally well with a pressure vessel 74. Although the embodiment of Figure 5 is disclosed as using a single cooling circuit 70 (primary cooling circuit), this embodiment uses a primary cooling circuit 70 and a secondary cooling circuit (as disclosed with reference to Figure 4). It is understood that it will function the same using a combination of 60).

Figure 6 shows a third embodiment of the engine. In this embodiment, structures and features that are the same or similar to corresponding structures and features previously described or shown are denoted by the same reference numerals as previously used for simplicity. Since the engine and its operation in this embodiment are almost identical to the previous embodiment, only the differences from the previous embodiment will be described in detail.

The third embodiment is basically the same as the second embodiment except that a pressure vessel 74 is used to accommodate the pressure and accommodate the expansion and contraction of water in the primary circulation conduit 73. Also the supply conduit 84 is not provided with an orifice 93, instead an orifice 98 is arranged in the primary circulation conduit 73 downstream of the engine water outlet 42. The return valve between the primary circulation pump (72) and the engine water inlet (41) may become stagnant, for example due to a failure of the circulation pump (72) or lack of power to the electric motor driving the circulation pump (72). Prevents the flow of water from the engine inlet toward the primary circulation pump in situations where Therefore, in this situation with stagnation of water in the primary circulation conduit 73 , for example water in the annular cooling chamber 23 can only escape via the engine water outlet 42 . However, orifice 98 throttles the flow from annular cooling chamber 23 and cylinder cover 22 to pressure vessel 74. However, during normal operation the orifice 98 should not restrict the circulation of water in the primary circulation conduit 73. Accordingly, optionally a second control valve 97 is arranged in parallel with the orifice 98 . The second control valve 97 is normally open and automatically closed, for example, when water stagnates in the primary circulation conduit 73. The second control valve responds to a lack of flow in the primary circulation circuit 73 by means of a hydraulic or hydrodynamic device or optionally by a signal, for example a signal that the primary circulation pump 72 is not operating or a signal that the primary circulation pump 72 is not operating. It can be selectively triggered to automatically close by another signal indicating stagnation of water in the conduit.

Although the embodiment of Figure 6 is disclosed using a pressure vessel 74, it is understood that this embodiment will function equally well with an expansion tank 77. While the embodiment of FIG. 6 is disclosed as using a single cooling circuit 70 (primary cooling circuit), this embodiment uses a primary cooling circuit 70 and a secondary cooling circuit (as disclosed with reference to FIG. 4 ). It is understood that it will function the same using a combination of 60).

Various aspects and implementations have been described in connection with various embodiments. Embodiments may be combined in various ways. Additionally, other modifications to the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed subject matter, from reference to the drawings, disclosure, and appended claims. In a claim, the word "comprising" does not exclude another element or step, and the indefinite article "a" or "an" does not exclude a plurality. A single processor, controller or other unit may perform the functions of several items recited in the claims. Just because certain measures are mentioned in different dependent claims does not mean that a combination of these measures cannot be used to advantage. Reference signs used in the claims should not be construed as limiting their scope.

Claims (28)

A large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead, comprising:
a plurality of combustion chambers each defined by a cylinder liner (1), a piston (10) configured to reciprocate in the cylinder liner (1), and a cylinder cover (22);
a scavenging port (18) arranged in each cylinder liner (1) for introducing scavenging gas into the combustion chamber;
at least one cooling channel in the cylinder cover (22),
an annular cooling chamber (23) surrounding a portion of each cylinder liner (1);
an exhaust gas outlet arranged in each cylinder cover (22) and controlled by an exhaust valve (4);
the plurality of combustion chambers being connected to the scavenging gas receiver (2) via a scavenging port (18) and to the exhaust gas receiver (3) via an exhaust gas outlet;
An exhaust gas system comprising a turbine (6) of a turbocharger system (5) driven by a flow of exhaust gases,
an air inlet system comprising a compressor (7) of the turbocharger system (5), wherein the compressor (7) is configured to supply pressurized scavenge gas to the scavenge gas receiver (2);
At least one primary circulation pump (72) configured to circulate water in the primary cooling circuit (70), comprising at least one cooling channel in the cylinder cover (22) and preferably also in the plurality of combustion chambers. The annular cooling chamber (23) includes a primary cooling circuit (70) that is part of the primary cooling circuit (70),
A pressure vessel (74) or expansion tank (77) is connected to the primary cooling circuit (70) by fluid connections (73, 84, 85, 87) to allow expansion and contraction of water in the primary cooling circuit (70). become,
The fluid connection is formed by one or more conduits (73, 84, 85, 87), each conduit for throttling the flow of water from the primary cooling circuit (70) to the pressure vessel (74) or expansion tank (77). Characterized by comprising orifices (87, 88, 93, 98),
engine. According to paragraph 1,
Orifices (87, 88, 93, 98) provide at least 50 times the flow, preferably at least 100 times, most preferably at least 150 times the flow relative to one or more conduits (73, 84, 85, 87) forming a fluid connection. reducing the cross-sectional area available to,
engine. According to paragraph 2,
One or more conduits (73, 84, 85, 87) have a substantially constant internal diameter of 35 mm to 80 mm, and at least one orifice (87, 88, 93, 98) has a minimum diameter of 3 to 5 mm. ,
engine. According to any one of the preceding claims,
Preferably, when the water contracts in the cooling circuit 70, at least one orifice 87, 88 is provided to allow water to flow from the pressure vessel 74 or expansion tank 77 into the primary cooling circuit 70. , 93, 98), a supply conduit fluidly connecting the pressure vessel 74 or expansion tank to the fluid connections 73, 84, 85, 87, preferably to the de-aerator 78. Comprising a first check valve (91) at (84),
engine. According to any one of the preceding claims,
Preferably, when the pressure of the water in the primary cooling circuit 70 rises above a threshold due to the expansion of the water in the primary cooling circuit 70, water is discharged from the primary cooling circuit 70 into the pressure vessel 74 or In parallel with one of the at least one orifices (87, 88, 93, 98) to allow flow to the expansion tank (77), at the fluid connection (73, 84, 85, 87), preferably a de-aerator ( 78) comprising a pressure setting valve (92) in the supply conduit (84) fluidly connecting the pressure vessel (74) or expansion tank.
engine. According to any one of the preceding claims,
to the fluid connections 73, 84, 85, 87, preferably in parallel with one of the at least one orifices 87, 88, 93, 98, for initially filling the cooling circuit 70 with water. comprising a first control valve (94) in the supply conduit (84) fluidly connecting the pressure vessel (74) or expansion tank (77) to the deaerator (78),
engine. According to any one of the preceding claims,
- Engine coolant inlet (41) and engine coolant outlet (42),
- a primary circulation conduit (73) extending from the engine coolant outlet (42) to the engine coolant inlet (41), and
- to the pressure vessel (74) or expansion tank (93) by means of a supply conduit (84) arranged in the circulation conduit (73) and comprising an orifice (93) and a first vent conduit (85) comprising an orifice (87). A connected de-aerator (87), and
- preferably comprising a second vent conduit (87) connecting the engine water outlet (42) to the pressure vessel (74) or expansion tank (77) and comprising an orifice (88).
engine. In clause 7,
An orifice (98) is arranged in the primary circulation conduit (73) at a position upstream of the deaerator (87), and a second control valve (97) is arranged in parallel with the orifice (98).
engine. According to paragraph 7 or 8,
At least one primary circulation pump 72 is arranged upstream of the de-aerator 78,
engine. According to any one of claims 7 to 9,
comprising a cooler (79) for cooling the water in the primary cooling circuit (70), the cooler being preferably arranged in parallel with a cooler limiter (83) arranged in the primary circulation conduit (73) and cooler (79) ) is preferably connected to the circulation circuit 73 by a third valve 71 and the third control valve 71 is preferably controlled by the controller 100,
engine. According to any one of the preceding claims,
a controller (100) receiving a first signal indicative of the temperature of the water in the cooling circuit (70), preferably close to the position where the water leaves the engine and enters the primary circulation conduit (73);
The controller 100 is configured to control the temperature of the water in the primary cooling circuit 70 to a temperature of at least 100° C., preferably between 120 and 130° C.
engine. According to clause 11,
By applying a selective amount of cooling to the water in the primary cooling circuit 70 under the control of the controller 100 to adjust the amount of cooling controlled by the controller 100 and applied to the water in the primary cooling circuit 70. comprising a cooler (79) configured to control the temperature of the water in the primary cooling circuit (70) to a temperature of at least 100° C., preferably between 120 and 130° C.
engine. According to any one of the preceding claims,
The engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load, and the controller 100 is configured to operate over the maximum engine load, and preferably over the entire engine load range between the minimum engine load and the maximum engine load. configured to control the temperature of the water in the primary cooling circuit (70) to a temperature above 100°C, preferably close to the position where the water leaves the engine and enters the primary circulation conduit (73). felled,
engine. According to any one of the preceding claims,
Primary cooling circuit 70 is connected to a pressure vessel 78 or expansion tank 77 to allow expansion and contraction of water in primary cooling circuit 70.
engine. According to any one of the preceding claims,
The primary cooling circuit 70 includes a first portion internal to the engine and a second portion external to the engine, the first portion extending from the engine inlet 41 to the engine outlet 42, and the first portion comprising: Comprising a cooling chamber (23), and preferably at least one channel of the cylinder cover (22) and preferably at least one channel and/or chamber of the housing of the exhaust valve (4).
engine. According to clause 15,
The second part comprises a primary circulation conduit (73), the circulation conduit (73) comprising at least one primary circulation pump (72), a de-aerator (78) upstream of the at least one primary circulation pump (72) ), and preferably a cooling device (71, 79, 83) upstream of the deaerator (78).
engine. According to any one of the preceding claims,
Comprising an annular water jacket (21) surrounding at least a part of the cylinder liner (1) and defining an annular cooling chamber (23) with the radially outer side of the cylinder liner (1).
engine. A large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead, comprising:
a plurality of combustion chambers each defined by a cylinder liner (1), a piston (10) configured to reciprocate in the cylinder liner (1), and a cylinder cover (22);
at least one cooling channel in the cylinder cover (22),
a scavenging port (18) arranged in each cylinder liner (1) for introducing scavenging gas into at least one combustion chamber;
an annular cooling chamber (23) surrounding a portion of each cylinder liner (1);
an exhaust gas outlet arranged in each cylinder cover (22) and controlled by an exhaust valve (4);
the plurality of combustion chambers being connected to the scavenging gas receiver (2) via a scavenging port (18) and to the exhaust gas receiver (3) via an exhaust gas outlet;
An exhaust gas system comprising a turbine (6) of a turbocharger system (5) driven by a flow of exhaust gases,
an air inlet system comprising a compressor (7) of the turbocharger system (5), wherein the compressor (7) is configured to supply pressurized scavenge gas to the scavenge gas receiver (2);
a secondary circulation pump (62) configured to circulate water in the secondary cooling circuit (60), comprising at least one cooling channel in the cylinder cover (22) and preferably also in the plurality of combustion chambers (1). The cooling chamber 23 includes a secondary cooling circuit 60, which is part of the secondary cooling circuit 60;
The secondary cooling circuit 60 provides fluid to the primary cooling circuit 70 by valve systems 56, 57 for mixing water from the primary cooling circuit 70 with the water in the secondary cooling circuit 60. connected to the enemy,
The primary cooling circuit (70) includes at least one primary circulation pump (72) for circulating water in the primary cooling circuit (70),
A controller 100 that receives a first signal representing the temperature of the water in the secondary circuit 60 and a second signal representing the temperature of the water in the primary cooling circuit 70,
Controller 100 preferably controls valve systems 56, 57 to adjust the amount of water from primary cooling circuit 70 mixed with water in secondary cooling circuit 60 to achieve a temperature below 95°C. and configured to control the temperature of the water in the primary cooling circuit (70) and to control the temperature of the water in the secondary cooling circuit (60) to a temperature above 100°C, preferably to a temperature between 120°C and 140°C. ,
engine. According to clause 18,
The engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load, and the controller 100 is configured to operate for the maximum engine load, and preferably for engine loads between the intermediate engine load and the maximum engine load, and More preferably configured to control the temperature of the water in the secondary cooling circuit (60) to a temperature above 100° C. for engine loads between the minimum and maximum engine loads.
engine. According to claim 18 or 19,
The valve system 56 , 57 comprises a fourth control valve 56 , preferably a three-way control valve controlled by a controller 100 , wherein the fourth control valve 56 controls the primary cooling circuit 70 and is fluidly connected to the secondary cooling circuit 60 via a return conduit 82, and the fourth control valve 56 has a size controllable from the secondary cooling circuit 60 via the return conduit 82. configured to branch the flow of water,
engine. According to clause 20,
Comprising a supply conduit (81) connecting the secondary cooling circuit (60) to the primary cooling circuit (70), preferably upstream of the fourth control valve (56).
engine. According to claim 20 or 21,
The valve system (56, 57) is connected to the secondary cooling circuit (60), preferably at the point where the return conduit (82) is connected to the secondary cooling circuit (60) and the supply conduit (81) is connected to the secondary cooling circuit (60). ), comprising a second non-return valve 57 arranged between positions connected to
engine. According to any one of claims 18 to 22,
Comprising a cooler (79) for cooling the water in the secondary cooling circuit (70),
engine. According to any one of claims 18 to 23,
arranged in the primary cooling circuit conduit (70), for regulating the water pressure in the primary and secondary cooling circuits (60, 70) and allowing expansion and contraction of water in the primary and secondary cooling circuits (60, 70). and a de-aerator (87) connected to a pressure vessel (74) or expansion tank (77), wherein the water of the secondary cooling circuit (60) is preferably configured to maintain sufficient pressure to prevent boiling for water temperatures of up to 140°C, preferably up to 130°C,
engine. A method of operating a large two-stroke turbocharged uniflow scavenging internal combustion engine having a crosshead, comprising:
The engine is
a plurality of combustion chambers each defined by a cylinder liner (1), a piston (10) configured to reciprocate in the cylinder liner (1), and a cylinder cover (22);
at least one cooling channel in the cylinder cover (22),
a scavenging port (18) arranged in each cylinder liner (1) for introducing scavenging gas into at least one combustion chamber;
an annular cooling chamber (23) surrounding a portion of each cylinder liner (1);
an exhaust gas outlet arranged in each cylinder cover (22) and controlled by an exhaust valve (4);
the plurality of combustion chambers being connected to the scavenging gas receiver (2) via a scavenging port (18) and to the exhaust gas receiver (3) via an exhaust gas outlet;
An exhaust gas system comprising a turbine (6) of a turbocharger system (5) driven by a flow of exhaust gases,
an air inlet system comprising a compressor (7) of the turbocharger system (5), wherein the compressor (7) is configured to supply pressurized scavenge gas to the scavenge gas receiver (2);
a secondary circulation pump (62) configured to circulate water in the secondary cooling circuit (60), comprising at least one cooling channel in the cylinder cover (22) and preferably also in the plurality of combustion chambers (1). The cooling chamber 23 includes a secondary cooling circuit 60, which is part of the secondary cooling circuit 60,
Primary cooling circuit 60 provides fluid to primary cooling circuit 70 by valve systems 56, 57 for mixing water from primary cooling circuit 70 with water from secondary cooling circuit 60. connected to the enemy,
The primary cooling circuit (70) includes comprising at least one primary circulation pump (72) for circulating water in the primary cooling circuit (70),
Detecting the temperature of water in the secondary circuit 60,
Detecting the temperature of water in the primary cooling circuit (70),
controlling the temperature of the water in the primary cooling circuit (70) to a temperature below 95° C., and
controlling the temperature of the water in the secondary cooling circuit (60) to a temperature above 100°C, preferably to a temperature between 120°C and 140°C.
method. According to clause 25,
the engine is configured to operate with an engine load range between the minimum engine load and the maximum engine load,
At a temperature above 100°C, at least for the maximum engine load, and preferably for engine loads between the intermediate and maximum engine loads, and more preferably for engine loads between the minimum and maximum engine loads, comprising controlling the temperature of the water in the secondary circuit, preferably at a temperature of 120 to 140° C.
method. According to claim 25 or 26,
The step of controlling the water temperature in the secondary cooling circuit 60 controls the amount of water from the primary cooling circuit 70 mixed with the water in the secondary cooling circuit 60 by controlling the valve systems 56 and 57. Including the steps of:
method. According to any one of claims 25 to 27,
maintaining a pressure of at least 5 bar in the primary and secondary cooling circuits (60, 70),
method.