• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An internal combustion engine comprising one or more cylinders (1), a combustion cell (40), a fuel gas supply system (30) configured for supplying a flow of fuel gas at a given pressure and temperature to the cylinders (1) and configured for supplying a flow of the fuel gas at the same given pressure and temperature to the combustion cell (40). The one or more cylinders (1) each being provided with at least one gas admission valve (31), the combustion cell (40) being provided with a nozzle (49) for injecting the flow of fuel gas from the fuel gas supply system (30) into the combustion cell (40). The engine further comprises a supply line (42) for supplying a flow of oxidizer gas to the combustion cell (40), an exhaust conduit (47) for conveying a flow of combustion gas away from combustion cell (40) and a sensor (48) for measuring the proportion of oxygen in the flow of combustion gas.
    公开号:DK201670286A1
    申请号:DKP201670286
    申请日:2016-05-02
    公开日:2017-12-11
    发明作者:Stefan Mayer
    申请人:Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland；
    IPC主号:
    专利说明:

    A INTERNAL COMBUSTION ENGINE WITH FUEL GAS PROPERTY MEASUREMENT SYSTEM
    TECHNICAL FIELD
    The disclosure relates to internal combustion engines that are operated on fuel gas.
    BACKGROUND
    Internal combustion engines, such as two-stroke engines, four stroke engines, using the Otto or Diesel principle can be operated with a liquid fuel or with a gaseous fuel. For proper operation of modern engines the load of the engine needs to be known accurately. This information is needed to control various parameters such as e.g. injection timing- and length exhaust valve opening timing- and length, variable turbocharger setting, SCR setting, EGR setting, gas pressure for injection, hydraulic system pressure, exhaust gas bypass opening degree, cooling fan speed, cooling liquid pump setting. This is not exhaustive and depends on the engine type. However, all internal combustion engines have in common that the load needs to be determined accurately for proper operation .
    In the art it is known to measure the torque and rotational speed of the crankshaft and to derive the engine load from this information. It is also known to measure the amount of fuel consumed to determine the load. However, this requires that the properties of the fuel, especially the calorific properties and density are known or can be determined accurately. For gaseous fuels it is more difficult to determine density of the fuel delivered due to variations in the pressure, temperature and it is typically more difficult to determine the calorific properties due to variations in the composition of the gas that is delivered to the combustion chambers in the engine.
    One way of determining the properties of the gaseous fuel is to use a gas chromatograph, and to take samples at timed intervals. By analyzing the gas composition it is possible to compute the necessary information on the properties of the gas. However, taking samples at timed intervals with e.g. a gas chromatograph is expensive and time-consuming, and does not provide instantaneous results so that the engine is always operating on information that is outdated, typically at least a few minutes outdated. This delay between the actual gas sampling and the outlet of the measurement result decreases the accuracy of the operation of the engine.
    Other available instruments measure or output a standard Wobbe index. The Wobbe Index is an indicator of the interchangeability of fuel gases. The Wobbe Index, Iw, is defined as: Iw = Vc/ (sqrt Gs) , with Vc being the higher calorific value, and Gs being the specific gravity.
    The Wobbe Index is used to compare the combustion energy output of different composition fuel gases in an appliance. If two fuels have identical Wobbe Indices then for given pressure and valve settings the energy output will also be identical.
    However, the Wobbe index is not precisely the information that is needed to accurately determine the engine load since the Wobbe Index will only provide a comparison between gas qualities/properties.
    There is therefore a need to determine the fuel gas properties and its state as delivered to the engine accurately and without significant delay, in order to be able to improve control of internal combustion engines operated on fuel gas.
    SUMMARY
    It is an object of the invention to provide a system that overcomes or at least reduces the problem indicated above.
    The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures .
    According to a first aspect there is provided an internal combustion engine comprising one or more cylinders, a combustion cell, a fuel gas supply system configured for supplying a flow of fuel gas at a given pressure and temperature to the cylinders and configured for supplying a flow of the fuel gas at the same given pressure and temperature to the combustion cell, the one or more cylinders each being provided with at least one gas admission valve, the combustion cell being provided with a nozzle for injecting the flow of fuel gas from the fuel gas supply system into the combustion cell, a supply line for supplying a flow of oxidizer gas to the combustion cell, an exhaust conduit for conveying a flow of combustion gas away from combustion cell, and a sensor arrangement for measuring the proportion of oxygen in the flow of combustion gas. A direct measure of the energy or of a value representing the calorific property of the fuel gas that is injected though the nozzle of the combustion cell can be determined under the exact same conditions that apply to the fuel gas supplied to the gas admission valves of the internal combustion engine. This information can be used directly in the engine control without any further correction to take account of the fuel gas temperature and pressure or other calibration. The range of permitted/feasible gas qualities for internal combustion engines can thus be greatly widened. The system, can be directly integrated either into either the internal combustion engine itself or in the gas valve train (gas supply system).
    According to a first possible implementation of the first aspect the engine comprises an arrangement to keep the oxygen mass rate in the flow of oxidizer gas kept constant.
    According to a second possible implementation of the first aspect the engine comprises an arrangement to control the oxygen mass rate in the flow of oxidizer gas.
    According to a third possible implementation of the first aspect the engine comprises an arrangement for measuring the flow rate of oxidizer gas supplied to the combustion cell or the oxygen mass rate in the flow of oxidizer gas supplied to the combustion cell.
    According to a fourth possible implementation of the first aspect the engine comprises a control unit informed of the oxygen mass rate in the oxidizer gas flow to the combustion cell and in receipt of a signal from the arrangement for measuring the proportion of oxygen in the flow of combustion gas .
    According to a fifth possible implementation of the first aspect the engine comprises a control unit configured to determine the energy that is injected through the nozzle on the basis of the signal from the arrangement for measuring the oxygen mass rate in the oxidizer gas flow and the signal from the arrangement for measuring the proportion of oxygen in the flow of combustion gas.
    According to a sixth possible implementation of the first aspect the control unit is configured to determine a value representative of the calorific value of the fuel gas supplied to the cylinders and the combustion cell.
    According to a seventh possible implementation of the first aspect the engine comprises a control unit configured to determine the energy that is injected or admitted through the fuel admission valves into the one or more cylinders taking into account the amount of energy that is injected through the nozzle or taking into account the value representative of the calorific value of the fuel gas supplied to the cylinders and the combustion cell.
    According to an eighth possible implementation of the first aspect the control unit is configured to determine the engine load from the amount of energy that injected or admitted via the fuel admission valves into the one or more cylinders.
    According to a ninth possible implementation of the first aspect the control unit is informed of the relation between the size of the nozzle and the size of the fuel admission valves .
    According to a tenth possible implementation of the first aspect the control unit is informed of the exact size of the nozzle and the exact size of the fuel admission valves.
    According to an eleventh possible implementation of the first aspect the control unit is configured to use the value representative of the calorific value of the fuel gas supplied to the cylinders and the combustion cell as a correction factor for calculating the engine load
    According to a twelfth possible implementation of the first aspect the oxidizer gas is air
    According to a thirteenth possible implementation of the first aspect the oxidizer gas is a mixture of air with additional nitrogen .
    According to a fourteenth possible implementation of the first aspect the oxidizer gas has an oxygen content that is lower than the oxygen content of ambient air.
    According to a fifteenth possible implementation of the first aspect the combustion cell is provided with an oxidation catalyst.
    According to a sixteenth possible implementation of the first aspect the combustion cell is provided with a cooling system.
    According to a seventeenth possible implementation of the first aspect the arrangement for determining the proportion of oxygen in the combustion gas flow comprises a lambda sensor .
    According to an eighteenth possible implementation of the first aspect the control unit is configured control the oxygen mass rate or the flow rate of oxidizer gas in response to the signal from the arrangement for determining the proportion of oxygen in the combustion gas.
    According to a nineteenth possible implementation of the first aspect the flow rate of the flow of fuel gas to the combustion cell is small compared to the flow rate of the flow of fuel gas to the one or more cylinders.
    According to a twentieth possible implementation of the first aspect the control unit is configured to determine the amount of oxygen consumed during combustion in the combustion cell.
    According to a twenty-first possible implementation of the first aspect the combustion cell is calibrated, i.e. the nozzle size is determined, using a known gas, preferably a pure gas, such as e.g. pure methane. Knowing the needed oxygen consumption of the combustion cell with a known gas, all other gases can then be treated as a deviation from that reference case .
    According to a second aspect, there is provided a method for determining a property of fuel gas in an internal combustion engine that is operated on fuel gas, the method comprising: supplying fuel gas to the cylinders of the engine at a given pressure and temperature and supplying a flow of the fuel gas to a combustion cell at the same given pressure and given temperature, supplying a flow of oxidizer gas to the combustion cell, burning the fuel gas with the oxidizer gas in the combustion cell thereby creating a flow of combustion gas, and measuring the proportion of oxygen in the combustion gas .
    According to a first possible implementation of the second aspect the method further comprises determining or controlling the oxygen mass rate in the oxidizer gas flow, preferably in response to the measured proportion of oxygen in the combustion gas.
    According to a second possible implementation of the second aspect the method further comprises determining a value representative of the calorific properties of the fuel gas.
    According to a third possible implementation of the second aspect the method further comprises determining the engine load based on the time that fuel admission valves of the engine are open and on the value representative of the calorific properties of the fuel gas.
    According to a fourth possible implementation of the second aspect the method further comprises determining the amount of oxygen consumed during combustion in said combustion cell. These and other aspects of the invention will be apparent from and the embodiment described below.
    BRIEF DESCRIPTION OF THE DRAWINGS
    In the following detailed portion of the present disclosure, the invention will be explained in more detail with reference to the example embodiments shown in the drawings, in which:
    Fig. 1 is an elevated front view of a large two-stroke diesel engine according to an example embodiment,
    Fig. 2 is an elevated side view of the large two-stroke engine of Fig. 1,
    Fig. 3 is a diagrammatic representation the large two-stroke engine according to Fig. 1, and
    Fig. 4 is a diagrammatic representation of a system for determining the properties of the fuel gas supplied to the cylinders of the engine, and
    Fig. 5 is a flow chart illustrating a method for determining the properties of fuel gas to the cylinders of the engine.
    DETAILED DESCRIPTION
    In the following detailed description, an internal combustion engine will be described with reference to a large two-stroke low-speed turbocharged compression-ignited internal combustion engine with crossheads in the example embodiments, but it is understood that the internal combustion engine could be of another type, such as a two-stroke Otto, a four-stoke Otto or Diesel, with- or without turbocharging, with or without exhaust gas recirculation.
    Figs. 1, 2 and 3 show a large low-speed turbocharged two-stroke diesel engine with a crankshaft 8 and crossheads 9. Fig. 3 shows a diagrammatic representation of a large low-speed turbocharged two-stroke diesel engine with its intake and exhaust systems. In this example embodiment the engine has six cylinders in line. Large low-speed turbocharged two-stroke diesel engines have typically between four and fourteen cylinders in line, carried by a cylinder frame 23 that is carried by an engine frame 11. The engine may e.g. be used as the main engine in a marine vessel or as a stationary engine for operating a generator in a power station. The total output of the engine may, for example, range from 1,000 to 110,000 kW.
    The engine is in this example embodiment a compression-ignited engine of the two-stroke uniflow type with scavenge ports 18 at the lower region of the cylinder liners 1 and a central exhaust valve 4 at the top of the cylinder liners 1. The scavenge air is passed from the scavenge air receiver 2 to the scavenge ports 18 of the individual cylinders 1. A piston 10 in the cylinder liner 1 compresses the scavenge air, fuel is injected through fuel injection valves 31 in the cylinder cover 22, combustion follows and exhaust gas is generated.
    When an exhaust valve 4 is opened, the exhaust gas flows through an exhaust duct associated with the cylinder 1 into the exhaust gas receiver 3 and onwards through a first exhaust conduit 19 to a turbine 6 of the turbocharger 5, from which the exhaust gas flows away through a second exhaust conduit via an economizer 20 to an outlet 21 and into the atmosphere. Through a shaft, the turbine 6 drives a compressor 7 supplied with fresh air via an air inlet 12. The compressor 7 delivers pressurized scavenge air to a scavenge air conduit 13 leading to the scavenge air receiver 2. The scavenge air in conduit 13 passes an intercooler 14 for cooling the scavenge air.
    The cooled scavenge air passes via an auxiliary blower 16 driven by an electric motor 17 that pressurizes the scavenge air flow when the compressor 7 of the turbocharger 5 does not deliver sufficient pressure for the scavenge air receiver 2, i.e. in low- or partial load conditions of the engine. At higher engine loads the turbocharger compressor 7 delivers sufficient compressed scavenge air and then the auxiliary blower 16 is bypassed via a non-return valve 15.
    The engine is operated with fuel gas, such as for example natural gas, coal gas, biogas, landfill gas, methane, ethylene, LPG and supplied by a gas supply system 30 in gaseous form at a substantially stable pressure and temperature. However, depending on the details of the gas supply system and the type of gas supplied slight variations in temperature and pressure are unavoidable. Further, slight variations in the composition of the gaseous fuel can also occur.
    The gas supply system supplies all the fuel injection valves 31 with gaseous fuel under pressure. An electronic control unit 60 of the engine is in receipt of signals from various sensors via signal lines illustrated in Fig. 3 as interrupted lines. The signals from the various sensors include e.g. charging pressure and temperature, exhaust pressure and temperature and crank angle and speed, although it is noted that this list is not exhaustive and will depend on the construction of the engine, for example whether it includes exhaust gas recirculation or not, whether it includes a turbocharger or not, etc. The electronic control unit 60 controls the fuel injection valves 31, i.e. the electronic control unit determines when the fuel valve 31 open and determines the length of the opening time. The timing of the opening of the fuel valves highly affects the combustion pressure in a Diesel engine (compression ignited engine) and the duration of the opening of the fuel valves determines the amount of fuel admitted to the cylinders 1, with increasing duration leading to increasing amount of fuel being admitted to the cylinders 1. The electronic control unit 60 is configured to determine the engine load from the combined duration of the opening of all of the fuel valves 31. Since the electronic control unit 60 determines the length of the duration of the fuel valves 31, the electronic control unit 60 is perfectly informed of the combined duration of the opening time of all of the fuel valves 31.
    However, the properties of the fuel gas, such as temperature, pressure and composition of the fuel gas delivered to the fuel injection valves 31 can fluctuate and thereby cause inaccuracies in the calculation of the engine load. This could be problematic, since the engine load is the most important control parameter for the control of the operation of the internal combustion engine. The engine load affects many aspects of the operation of the internal combustion engine, such as e.g. the pressure in the hydraulic system, the timing of the opening of the exhaust valve, the timing of start of the fuel injection, the operation of an exhaust gas bypass, and the opening degree of the valve in such exhaust gas bypass, the setting of the variable turbocharger, activation and deactivation of SCR operation, activation and deactivation gas pressure of the fuel gas, etc.
    It is therefore important to be informed accurately and without (substantial) delay of the amount of energy that is injected through the fuel valves 31 during the open period of the fuel valve 31. For liquid fuels, such as diesel oil the variations due to pressure, temperature and composition of the diesel oil are negligible and thus by knowing the total duration of the opening of the fuel valves the engine load can be determined quite accurately for internal combustion engines are operated on diesel oil or other liquid fuel. This is unfortunately not the case for an engine operated on fuel gas, since the variations in pressure, temperature and composition of the fuel gas are not negligible.
    In order to be able to determine the engine load accurately from the duration of the opening of the fuel valves, the engine is provided with the system illustrated in Fig. 4.
    This system provides the information needed to adjust the engine load calculation, so that the engine load calculation can be based on the total duration of the time of the fuel valves, but adjusted for variations in the gaseous fuel supplied to the cylinders 1 in order to arrive at an accurate and instantaneous result.
    The gaseous fuel supply system 30 supplies the cylinders 1 through the fuel valves 31 with gaseous fuel at a given temperature and pressure. The gaseous fuel supply system 30 also supplies a combustion cell 40 with the same fuel gas at the same given pressure and temperature via a gaseous fuel supply conduit 41 that connects the fuel supply system 30 to a nozzle 49 and includes a valve 43. The valve 43 can be used to close off the gaseous fuel supply conduit 41.
    The nozzle 49 injects the fuel gas into the combustion cell 40 through one or more nozzle holes in the nozzle 49. The size of the nozzle 49 has been accurately determined, for example by calibration. The combination can be performed relative to the fuel valves 31 of the internal combustion engine concern or the calibration can be an absolute calibration. The size of the nozzle 49 is the size of the area of the one or more nozzle holes.
    The flow of fuel gas to the combustion cell 40 is very small when compared to the flow of fuel gas to the cylinders 1. The size of the nozzle 49 is preferably relatively small when compared to size of the fuel valves 31, in order to allow the flow of fuel gas to the combustion cell to be small as well. Since the supply of fuel gas to the combustion cell 40 is the same fuel gas at the same pressure and temperature as the fuel gas delivered to the cylinders 1, the nozzle 49 receives fuel gas at the same conditions as the fuel valves 31. A supply line 42 supplies a flow of oxidizer gas to the combustion cell 40. The oxidizer gas, is e.g. ambient air or ambient air diluted with nitrogen to reduce the oxygen content in the oxidizer gas relative to a mint air. When the ambient air is diluted with nitrogen, the oxidizer gas has a proportion of oxygen that is lower than that of ambient air, which has the advantage that the resulting combustion temperature is lower when compared to burning the fuel gas with air. In an embodiment the combustion cell 40 is provided with cooling means for managing the temperature of the combustion cell 40.
    The combustion cell 40 is in an embodiment provided with an oxidation catalyst the combustion process. Such oxidation catalyst are well known in the art. Alternatively, the combustion cell 40 can be provided with a simple ignition device, such as an electronic spark generating device.
    The supply line 42 includes in an embodiment a blower 44 a, a venturi 45, and a control valve 46. The pressure at the venturi 45 is measured in order to determine the flow rate of oxidizer gas into the combustion cell 40. The opening degree of the control valve 46 and the setting of the blower 44 are adjusted in order to control the flow rate of oxidizer gas into the combustion cell 40.
    An electronic control unit 50 controls the operation of the system. In an embodiment the electronic control unit 50 or controls the operation of the blower 44 and the electronic control valve 46. The electronic control unit 50 is in an embodiment in receipt of a signal from the pressure sensor at the venturi 45.
    The fuel gas is burned with the oxidizer gas in a chamber in combustion cell 40. The resulting combustion gas is discharged from the combustion cell 40 via an exhaust conduit 47. The exhaust conduit 47 is provided with a sensor 48 for measuring the proportion of oxygen in the flow of combustion gas. In an embodiment the sensor 48 is a lambda sensor 48. The electronic control unit 50 is in receipt of a signal from the sensor 48.
    The stream of oxidizing gas is controlled such that combustion in the combustion 40 takes place at controlled conditions, i.e. with a controlled stoichiometric coefficient. Preferably, the stoichiometric coefficient is kept between 1 and 2. In an embodiment it is preferred that combustion takes place at exact stoichiometric conditions, i.e. with a stoichiometric coefficient of 1.
    The stoichiometric coefficient is controlled by the electronic control unit 50 in response to the signal of the sensor 48 by controlling the operation of the blower 44 and/or the control valve 46 accordingly. Thus, the feedback of the sensor 48 is used to regulate the admission of oxidizer gas.
    The oxygen mass rate that is needed for the combustion at a controlled stoichiometric coefficient is monitored, preferably monitored continuously by the electronic control unit, e.g. with the signal from the venturi 45.
    In another embodiment, the system can be set up with an arrangement in the supply line 42 that keeps the oxygen mass rate constant without any control action of the control unit 50 and in this embodiment the electronic control unit 50 is simply informed of the value of the constant oxygen mass rate and determines the mass rate of oxygen used in the combustion process from the constant oxygen mass rate and the measured proportion of oxygen in the combustion gas.
    The oxygen mass rate is a direct measure of the chemical energy bound in the gas stream since a predetermined amount of heat can be freed for a given mass of oxygen. The amount of heat that can be freed per kilogram of air is approximately 3 MJ when the fuel gas consists of hydrocarbons (and the oxidizer gas is air). Thus, the oxygen mass rate or air mass rate used in the combustion process is directly proportional to the amount of energy injected through the nozzle per time unit. Since the nozzle size is in an embodiment calibrated relative to the size of the fuel valves 31 it becomes possible to accurately determine how much energy is injected through the fuel valves per time unit from knowing the exact amount of energy injected through the nozzle 49. This in turn allows exact calculation of the engine load by summing up the duration of the opening time of the fuel valves 31.
    In an embodiment the output signal of the system, for example a signal from the electronic control unit 50 to the electronic control unit 60 is in the form of a correction coefficient that corrects the engine load calculations of the electronic control unit 60 to the actual conditions of the fuel gas applied to the cylinders 1. Thus, the electronic control unit 60 can use the signal received from the electronic control unit 50 to adjust the engine load calculation and thereby render the engine load calculation more precise.
    The nature of the signal from the electronic control unit 50 to the electronic control unit 60 depends on the way in which the system is operated. If the system is operated with a constant flow of air or a constant oxygen mass flow into the combustion chamber, the resulting measured stoichiometric coefficient (measured e.g. with the lambda sensor 48) can be the input signal for the electronic control unit 64 determining the correction that needs to be applied to the calculation of the engine load on the basis of the duration of the opening of the fuel valves 31.
    If the system operates with controlling the size of the flow of oxidizer gas and keeping the stoichiometric coefficient constant, for example at 1, the input signal to the electronic control unit 60 could be the signal from the pressure sensor at the venturi 45. Based on this signal the electronic control unit 60 calculates the required adjustment of the engine load calculation. It is also feasible to measure the mass flow of oxidizer gas in other ways than with a venturi, such as for example using a hot-wire sensor or a moving vane meter. The signal from the arrangement for measuring or determining the size of the flow of oxidizer gas into the combustion cell 40 can be sent directly to the electronic control unit 60 or via the electronic control unit 50.
    In an embodiment the electronic control unit 50 is configured to determine the calorific value of the fuel gas supply to the combustion cell 40 and configured to transmit the determined calorific value to the electronic control unit 60. The calorific value may be expressed as Mw/mm2.
    In an embodiment the electronic control unit 60 is informed of the size of the fuel valves 31, i.e. the area of the nozzle holes in the nozzle of the fuel valves 31 relative to the size of the area of the nozzle hole or nozzle holes in the nozzle 49. The electronic control unit 60 can further be configured to determine the ratio between these two sizes and on the basis of this racial determine the exact amount of energy flowing through the injection valves 31.
    Although the electronic control unit 50 and the electronic control unit 60 have been described as separate electronic control units, it is understood that it is possible to provide the engine with one single electronic control unit that covers the functions of electronic control unit 50 and the electronic control unit 60.
    In an embodiment the combustion cell 40 is calibrated, i.e. the nozzle size is determined, using a known gas, preferably a pure gas, such as e.g. pure methane. Knowing the needed oxygen consumption of the combustion cell 40 with a known gas, all other gases can then be treated as a deviation from that reference case.
    Fig. 5 is a flowchart illustrating the operation of the system. The flow chart illustrates the principles of the method and the boxes in the flowchart do not represent consecutive steps. The method is used for determining a property of fuel gas in an internal combustion engine that is operated on fuel gas. The method includes supplying fuel gas to the cylinders 1 of the engine at a given pressure and temperature and supplying a flow of the fuel gas to a combustion cell 40 at the same given pressure and given temperature .
    The method further includes supplying a flow or oxidizer gas to the combustion cell 40, and burning the fuel gas with the oxidizer gas in the combustion cell 40 thereby creating a flow of combustion gas and measuring the proportion of oxygen in the combustion gas.
    The method includes determining or controlling the oxygen mass rate in the oxidizer gas flow supplied to the combustion cell 40. The control of the oxygen mass rate in the oxidizer gas flow supplied to the combustion cell 40 is preferably in response to the measured proportion of oxygen in the combustion gas .
    The method includes calculating the engine load based on the duration that fuel admission valves 31 of the engine are open, and adjusting the calculated engine load on the basis of the calculated oxygen mass rate used in the combustion process. The latter step may include calculating of the oxygen mass rate used in the combustion the basis of the measured or determined stoichiometric coefficient in relation to the measured or determined oxygen mass rate supplied to the combustion cell 40.
    In an embodiment the method may also comprise determining value representative of the calorific properties of the fuel gas. The method may in an embodiment include using the measured or determined calorific properties of the fuel in a calculation to determine the engine load.
    The invention has been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The reference signs used in the claims shall not be construed as limiting the scope.
    权利要求:
    Claims (22)
    [1] 1. An internal combustion engine comprising one or more cylinders (1), a combustion cell (40), a fuel gas supply system (30) configured for supplying a flow of fuel gas at a given pressure and temperature to the cylinders (1) and configured for supplying a flow of said fuel gas at the same given pressure and temperature to said combustion cell (40) , said one or more cylinders (1) each being provided with at least one gas admission valve (31), a supply line (42) for supplying a flow of oxidizer gas to the combustion cell (40), an exhaust conduit (47) for conveying a flow of combustion gas away from said combustion cell (40), and a sensor (48) for measuring the proportion of oxygen in the flow of combustion gas.
    [2] 2. An engine according to claim 1, comprising an arrangement (44,45) to keep the oxygen mass rate in said flow of oxidizer gas kept constant.
    [3] 3. An engine according to claim 1, comprising an arrangement (44,45,50) to control the oxygen mass rate in said flow of oxidizer gas.
    [4] 4. An engine according to any one of claims 1 to 3, comprising an arrangement (45) for measuring or determining the flow rate of oxidizer gas supplied to the combustion cell (40) or the oxygen mass rate in the flow of oxidizer gas supplied to the combustion cell (40).
    [5] 5. An engine according to any one of claims 1 to 4, further comprising a control unit (50) informed of the oxygen mass rate in the oxidizer gas flow to the combustion cell (40) and in receipt of a signal from the sensor (48) for measuring the proportion of oxygen in the flow of combustion gas.
    [6] 6. An internal combustion engine according to claim 5, wherein said control unit (50) is configured to determine the amount of oxygen consumed during combustion in said combustion cell.
    [7] 7. An engine according to claim 5 or 6, wherein said control unit (50) is configured to determine the energy that is injected through said nozzle (49) on the basis of the signal from said arrangement (45) for measuring or determining the oxygen mass rate in the oxidizer gas flow and the signal from the sensor (48) for measuring the proportion of oxygen in the flow of combustion gas.
    [8] 8. An engine according to claim 6 or 7, wherein said control unit (50) is configured to determine a value representative of the calorific value of the fuel gas supplied to the cylinders (1) and the combustion cell (40).
    [9] 9. An engine according to any one of claims 1 to 8, comprising a control unit (50) configured to determine the energy that is injected or admitted through said fuel admission valves (31) into said one or more cylinders (1) taking into account the amount of energy that is injected through said nozzle (49) or taking into account the value representative of the calorific value of the fuel gas supplied to the cylinders (1) and the combustion cell (40).
    [10] 10. An engine according to claim 9, wherein said control unit (50) is configured to determine the engine load from the amount of energy that is injected or admitted via said fuel admission valves (31) into said one or more cylinders (1).
    [11] 11. An engine according to any one of claims 1 to 10, wherein said control unit (50) is informed of the relation between the size of said nozzle (49) and the size of said fuel admission valves (31).
    [12] 12. An engine according to any one of claims 1 to 11, wherein said control unit (50) is informed of the exact size of said nozzle (49) and the exact size of said fuel admission valves (31), preferably by calibration.
    [13] 13. An engine according to any one of claims 9 to 12, wherein said control unit (50) is configured to use the value representative of the calorific value of the fuel gas supplied to the cylinders (1) and the combustion cell (40) as a correction factor for calculating the engine load.
    [14] 14. An engine according to any one of claims 1 to 13, wherein said oxidizer gas is a mixture of air with additional nitrogen.
    [15] 15. An engine according to any one of claims 1 to 143, wherein said oxidizer gas has an oxygen content that is lower than the oxygen content of ambient air.
    [16] 16. An engine according to any one of claims 1 to 15, wherein said sensor (48) for determining the proportion of oxygen in the combustion gas flow comprises a lambda sensor (48).
    [17] 17. An engine according to any one of claims 5 to 16, wherein said control unit (50) is configured to control the oxygen mass rate or the flow rate of oxidizer gas in response to the signal from the sensor (48) for determining the proportion of oxygen in the combustion gas.
    [18] 18. A method for determining a property of fuel gas in an internal combustion engine that is operated on fuel gas, said method comprising: supplying fuel gas to the cylinders (1) of the engine at a given pressure and temperature and supplying a flow of said fuel gas to a combustion cell (40) at the same given pressure and given temperature, supplying a flow of oxidizer gas to said combustion cell (40), burning said fuel gas with said oxidizer gas in said combustion cell (40) thereby creating a flow of combustion gas, and measuring the proportion of oxygen in said combustion gas.
    [19] 19. A method according to claim 18, further comprising determining or controlling the oxygen mass rate in said flow of oxidizer gas, preferably in response to the measured proportion of oxygen in said combustion gas.
    [20] 20. A method according to claim 18 or 19, further comprising determining a value representative of the calorific properties of said fuel gas.
    [21] 21. A method according to claim 20, further comprising determining the engine load based on the duration that the fuel admission valves (31) of the engine are open and on said value representative of the calorific properties of said fuel gas .
    [22] 22. A method according to any one of claims 17 to 21, further comprising determining the amount of oxygen consumed during combustion in said combustion cell (40).
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    同族专利:
    公开号 | 公开日
    KR20170124450A|2017-11-10|
    JP6306772B2|2018-04-04|
    DK179205B1|2018-02-05|
    KR101986275B1|2019-09-30|
    CN107339159A|2017-11-10|
    CN107339159B|2019-11-08|
    JP2017201175A|2017-11-09|
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    法律状态:
    优先权:
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    DKPA201670286A|DK179205B1|2016-05-02|2016-05-02|A internal combustion engine with fuel gas property measurement system|DKPA201670286A| DK179205B1|2016-05-02|2016-05-02|A internal combustion engine with fuel gas property measurement system|
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