JP2011185188A - Working gas circulation type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working gas circulation type engine adjustable the pressure of a combustion chamber properly. <P>SOLUTION: The working gas circulation type engine includes: the combustion chamber 11 in which a fuel and a working gas whose specific heat ratio is higher than that of air are supplied and the working gas can inflate along with the combustion of the fuel; a circulation path 20 which circulates the gas containing the working gas from the exhaust side to the intake side of the combustion chamber 11 and can supply it to the combustion chamber 11 again; an adjusting mechanism 70 provided in the circulation path 20 and adjustable the amount of working gas supplied to the combustion chamber 11; and a control device 60 that controls the adjusting mechanism 70 to reduce the amount of working gas to be supplied to the combustion chamber 11 according to the increase in a requested torque when the demanded torque is larger than a first predetermined torque set beforehand. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a working gas circulation engine.

  As a conventional engine, a working gas circulation type engine as a so-called closed cycle engine is known in which working gas is circulated from the exhaust side to the intake side of the combustion chamber and can be supplied to the combustion chamber again. As such a conventional working gas circulation engine, for example, Patent Document 1 discloses an internal combustion engine that increases the amount of working gas supplied to the combustion chamber as the required torque increases.

JP 2007-077784 A

  Incidentally, in the internal combustion engine described in Patent Document 1 as described above, for example, it has been desired that the pressure in the combustion chamber be adjusted to a more appropriate pressure.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a working gas circulation engine that can adjust the pressure in the combustion chamber to an appropriate pressure.

  In order to achieve the above object, a working gas circulation engine according to the present invention is provided with a combustion chamber in which a working gas having a higher specific heat ratio than fuel and air is supplied and the working gas can expand as the fuel burns. A circulation path in which a gas containing the working gas is circulated from the exhaust side to the intake side of the combustion chamber and can be supplied to the combustion chamber again, and the working gas provided in the circulation path and supplied to the combustion chamber When the required torque is larger than a first predetermined torque set in advance, the adjustment mechanism is controlled and supplied to the combustion chamber according to the increase in the required torque. And a control device for reducing the amount of the working gas.

  In the working gas circulation engine, the first predetermined torque may be a torque at which the pressure in the combustion chamber becomes a predetermined pressure set in advance.

  In the working gas circulation engine, the adjustment mechanism may include a variable throttle mechanism that makes a passage sectional area of the circulation path variable.

  In the working gas circulation engine, the variable throttle mechanism is supplied with the fuel or an oxidant that burns the fuel with reference to the combustion chamber with respect to a circulation direction of the circulating gas in the circulation path. It can be provided upstream of the supply position.

  In the working gas circulation engine, the adjusting mechanism may include a valve operating mechanism capable of adjusting an opening / closing operation of an intake valve capable of opening / closing an intake port communicating with the combustion chamber.

  Further, in the working gas circulation engine, the control device supplies an oxidant that burns the fuel supplied to the combustion chamber when the required torque is larger than a second predetermined torque set in advance. The amount can be controlled to be higher than the supply amount corresponding to the theoretical ratio of the combustion with the fuel.

  In the working gas circulation engine according to the present invention, when the required torque is larger than the first predetermined torque set in advance, the control device controls the adjustment mechanism and is supplied to the combustion chamber according to the increase in the required torque. Since the amount of the working gas is reduced, the pressure in the combustion chamber can be adjusted to an appropriate pressure.

FIG. 1 is a schematic configuration diagram of an engine according to the first embodiment. FIG. 2 is a diagram for explaining the argon reduction control of the engine according to the first embodiment. FIG. 3 is a diagram for explaining an example of the operation of the engine according to the first embodiment. FIG. 4 is a flowchart illustrating an example of control in the engine according to the first embodiment. FIG. 5 is a schematic schematic configuration diagram of an engine according to the second embodiment. FIG. 6 is a schematic configuration diagram of an engine according to the third embodiment. FIG. 7 is a flowchart illustrating an example of control in the engine according to the third embodiment. FIG. 8 is a diagram for explaining oxygen increase control of the engine according to the fourth embodiment. FIG. 9 is a flowchart illustrating an example of control in the engine according to the fourth embodiment. FIG. 10 is an example of a control map in the engine according to the fourth embodiment.

  Hereinafter, an embodiment of a working gas circulation engine according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram of an engine according to the first embodiment, FIG. 2 is a diagram illustrating argon reduction control of the engine according to the first embodiment, and FIG. 3 is an operation of the engine according to the first embodiment. FIG. 4 is a flowchart for explaining an example of control in the engine according to the first embodiment.

  An engine 1 as a working gas circulation engine of the present embodiment shown in FIG. 1 is supplied with an oxidant, fuel, and working gas in a combustion chamber 11 of an engine body 10, and the combustion chamber 11 accompanies combustion of fuel. The working gas expands to generate power. The engine 1 circulates the working gas from the exhaust side of the combustion chamber 11 to the intake side via a circulation path 20 that connects the intake side and the exhaust side of the combustion chamber 11 and basically releases it to the atmosphere. This is a so-called closed cycle engine that can be supplied to the combustion chamber 11 again without being performed. The combustion chamber 11 and the circulation path 20 are both filled with working gas, and the working gas circulates between the combustion chamber 11 and the circulation path 20.

Here, the oxidant used in the engine 1 is oxygen (O ₂ ), and the fuel is hydrogen (H ₂ ). Further, the working gas used in the engine 1 has a specific heat ratio higher than that of air, and here is a monoatomic gas, argon (Ar). Argon expands in the combustion chamber 11 due to reaction heat generated by the reaction between oxygen and hydrogen, that is, combustion heat generated by hydrogen combustion (exothermic reaction). That is, the engine 1 burns hydrogen in the combustion chamber 11 and thermally expands argon as the hydrogen burns to generate power, thereby improving thermal efficiency.

  Specifically, as shown in FIG. 1, the engine 1 includes an engine body 10 provided with a combustion chamber 11 in which oxygen and hydrogen react, and a circulation path 20 that connects an exhaust side and an intake side of the combustion chamber 11. And an oxygen supply device 30 for supplying oxygen, a hydrogen supply device 40 for supplying hydrogen, a condenser 50, and an electronic control device 60 as a control device.

The engine body 10 is configured to include a combustion chamber 11 to which oxygen, hydrogen, and argon are supplied and in which argon can expand as hydrogen is burned. The combustion chamber 11 can exhaust argon and water vapor (H ₂ O) as a combustion product after the combustion of hydrogen. The engine body 10 has a plurality of combustion chambers 11 (cylinders) (not shown). The circulation path 20 is configured to circulate a circulating gas containing argon from the exhaust side to the intake side of the combustion chamber 11 and supply it to the combustion chamber 11 again. The circulation path 20 includes an intake port 12 and an exhaust port 13 formed in the cylinder head and communicating with the combustion chamber 11, and various pipes. The circulation path 20 connects the intake port 12 and the exhaust port 13 outside the combustion chamber 11. It comprises a passage 21 and basically forms a circulatory system that is sealed against the outside air as a whole. The circulation path 20 is provided with a condenser 50 as a removal device that removes water vapor, which is a product generated by combustion from the circulation gas.

  Here, the circulating gas is a gas that is circulated from the exhaust side to the intake side of the combustion chamber 11 via the circulation path 20, and in addition to argon as a working gas, the combustion chamber after combustion of hydrogen in the combustion chamber 11. 11 and the like which include exhaust gas exhausted from the exhaust gas. Here, the exhaust gas includes, for example, surplus oxygen remaining after the combustion of hydrogen in the combustion chamber 11, surplus gas composed of hydrogen, water vapor as a product generated by the combustion of hydrogen, and the like. . That is, the circulating gas here includes argon as working gas, surplus oxygen after combustion, surplus gas composed of hydrogen, etc., water vapor, and the like.

  The oxygen supply device 30 injects oxygen into the circulation path 20 and supplies the oxygen to the combustion chamber 11 together with a circulation gas containing argon or the like. The hydrogen supply device 40 directly injects high-pressure hydrogen into the combustion chamber 11 and supplies it.

  The condenser 50 is provided in the circulation path 20 and removes most of the water vapor from the circulation gas circulating in the circulation path 20. The condenser 50 is driven by a cooling water pump 52 provided in the cooling water circulation path 51, so that cooling water as a cooling medium cooled by the radiator 53 is supplied to the inside through the cooling water circulation path 51. The condenser 50 cools the circulating gas by exchanging heat between the cooling water and the circulating gas, and liquefies and condenses the water vapor contained in the circulating gas into condensed water. To separate. Then, the circulating gas containing argon from which the water vapor has been separated by the condenser 50 circulates in the circulation path 20 as it is, and the condensed water condensed by the condenser 50 passes outside the circulation system of the circulation path 20 via the discharge valve 54. To be discharged.

  The electronic control device 60 is an electronic circuit mainly composed of a known microcomputer including a CPU, a ROM, a RAM, and an interface. The electronic control device 60 receives electrical signals corresponding to detection results detected by various sensors such as an accelerator opening sensor 61 that detects the accelerator opening and a crank angle sensor 62 that detects the crank angle. Here, the accelerator opening corresponds to the amount of operation of an accelerator pedal (not shown) provided at the driver's seat of the vehicle, and more specifically, the required engine load (required load factor) requested by the driver to the engine 1. ). The crank angle corresponds to the rotation angle of a crankshaft connected to the piston 16 via a connecting rod. For example, the electronic control unit 60 discriminates the intake stroke, compression stroke, expansion stroke, and exhaust stroke in each cylinder based on the crank angle detected by the crank angle sensor 62, and uses the engine speed (rpm) as the rotational speed of the engine 1. ) Is calculated. The electronic control device 60 outputs a drive signal to each part of the engine 1 such as the oxygen supply device 30, the hydrogen supply device 40, the cooling water pump 52, and the discharge valve 54 in accordance with the input detection result, and controls their drive. .

  The engine 1 configured as described above is exemplified as one that diffuses and burns hydrogen. In the engine 1, when the intake valve 14 provided in the intake port 12 is opened, the circulating gas circulating in the circulation path 20 is sucked (supplied) into the combustion chamber 11 together with oxygen from the oxygen supply device 30. The engine 1 injects high-pressure hydrogen from the hydrogen supply device 40 into a high-temperature compressed gas (oxygen and argon) formed in the combustion chamber 11 in accordance with the operation of the piston 16, thereby partially Ignites and burns while hydrogen and compressed gas (oxygen) are diffusely mixed. As a result, in the engine 1, steam is generated in the combustion chamber 11, and argon having a large specific heat ratio causes thermal expansion. As a result, the engine 1 can generate mechanical power by the piston 16 being pushed down by the combustion of hydrogen and the thermal expansion of argon, and the crankshaft rotating. When the exhaust valve 15 provided at the exhaust port 13 is opened, the engine 1 exhausts (exhausts) the exhaust gas after combustion of hydrogen from the combustion chamber 11 to the exhaust port 13 together with argon. And argon circulate through the circulation path 20 as a circulation gas and are again sucked into the combustion chamber 11. During this time, in the engine 1, most of the water vapor in the circulating gas is liquefied and condensed by the condenser 50 and separated. As a result, the engine 1 is not supplied with water vapor having a small specific heat ratio to the combustion chamber 11, and is again supplied with argon having a large specific heat ratio to the combustion chamber 11, so that the engine 1 can be operated with high thermal efficiency.

  During this time, the electronic control unit 60 determines the current engine load, engine speed, etc. based on the accelerator opening detected by the accelerator opening sensor 61, the crank angle detected by the crank angle sensor 62, etc. Oxygen and hydrogen supply amount (injection amount) and supply timing (injection timing) by the oxygen supply device 30 and the hydrogen supply device 40 so that the driving force (engine output) required by the driver can be obtained at the engine speed. ) To control. The electronic control device 60 basically has, for example, a supply amount map stored in advance in the storage unit in accordance with the driving state such as the accelerator opening and the engine speed corresponding to the amount of operation of the accelerator pedal by the driver. The supply amount and supply timing of hydrogen and oxygen that can obtain the required torque required at the current engine speed are determined from (not shown), and each part is controlled based on this.

  In addition, although this engine 1 was illustrated as a structure of the in-cylinder direct-injection self-ignition diffusion combustion type in which hydrogen is directly injected into the combustion chamber 11 to self-ignite and diffusely burn, it is not limited thereto. For example, the engine 1 may include a spark plug as an ignition device capable of igniting hydrogen supplied to the combustion chamber 11, and the spark plug may ignite hydrogen in the combustion chamber 11. Alternatively, a configuration may be adopted in which hydrogen is ignited with a spark plug to assist hydrogen self-ignition and diffuse combustion. Further, the engine 1 has, for example, an intake premixing configuration in which hydrogen is injected and supplied into the circulation path 20, here into the intake port 12, and supplied to the combustion chamber 11 together with a circulation gas containing argon or the like. Also good. The engine 1 may have a configuration in which oxygen is directly injected into the combustion chamber 11. Further, the engine 1 may have a so-called lean combustion type configuration.

  By the way, for example, when the engine 1 is operated so that the supply amount of argon is maximized within a range in which the combustion of hydrogen in the combustion chamber 11 does not become unstable, the engine 1 is supplied according to the increase in the required torque. The amount of argon also increases, and as a result, the pressure in the combustion chamber 11 may become too large. This is because the engine 1 using a working gas such as argon has a higher specific heat ratio of argon than that of air. Therefore, the thermal expansion of the gas in the combustion chamber 11 accompanying the combustion of fuel is greater than that of an engine that draws in normal air. This is because of the increase.

  Therefore, the engine 1 of the present embodiment is configured so that the electronic control device 60 reduces the supply amount of argon (working gas) supplied to the combustion chamber 11 in accordance with an increase in required torque under a predetermined condition. By executing gas) reduction control, the pressure in the combustion chamber 11 is adjusted to an appropriate pressure.

  Specifically, the engine 1 includes an adjustment mechanism 70, and the electronic control unit 60 controls the adjustment mechanism 70 according to the operating state, thereby executing the argon reduction control.

  The adjustment mechanism 70 is provided in the circulation path 20 and can adjust the amount of argon supplied to the combustion chamber 11, and has a variable throttle mechanism 71 here. The variable throttle mechanism 71 changes the cross-sectional area of the circulation path 20 and is electrically connected to the electronic control unit 60 to control its drive.

  The variable throttle mechanism 71 is located downstream of the supply position where hydrogen or oxygen is supplied, here the oxygen supply position where oxygen is supplied, with respect to the circulation direction of the circulating gas in the circulation path 20 with reference to the combustion chamber 11. Provided. The variable throttle mechanism 71 is provided between the oxygen supply position and the intake side of the combustion chamber 11.

  The variable throttle mechanism 71 adjusts the throttle amount of the passage between the oxygen supply position and the intake side of the combustion chamber 11 by driving a variable throttle valve provided in the circulation path 20, in other words, the circulation path 20. The amount of argon supplied to the combustion chamber 11 can be adjusted by adjusting the passage opening degree (passage cross-sectional area through which a fluid such as argon can pass). That is, the variable throttle mechanism 71 can reduce the amount of argon supplied to the combustion chamber 11 by relatively increasing the throttle amount and relatively reducing the passage opening degree of the circulation path 20. On the other hand, the variable throttle mechanism 71 can increase the amount of argon supplied to the combustion chamber 11 by relatively reducing the throttle amount and relatively increasing the passage opening degree of the circulation path 20.

  Then, as illustrated in FIG. 2, the electronic control unit 60 controls the adjustment mechanism 70 as the argon reduction control when the torque required for the engine 1 is larger than the first predetermined torque Tq1 set in advance. Thus, the amount of argon supplied to the combustion chamber 11 is reduced as the required torque increases. FIG. 2 schematically shows the ratio of the supply amounts of hydrogen, oxygen, and argon in the combustion chamber 11 at each required torque.

  Here, the first predetermined torque Tq1 is a torque at which the in-cylinder pressure, which is the pressure in the combustion chamber 11, becomes a predetermined pressure set in advance, and is set in advance based on experiments or the like. More specifically, the first predetermined torque Tq1 and the predetermined pressure are obtained by executing the above-described argon reduction control so that the maximum in-cylinder pressure, which is the maximum in-cylinder pressure in the combustion chamber 11, becomes the strength and specifications of the engine body 10 and the like. Is set to fall within an allowable range set in advance.

  When the required torque determined according to the accelerator opening and the engine speed based on the detection results of the accelerator opening sensor 61 and the crank angle sensor 62 is equal to or less than the first predetermined torque Tq1, the electronic control unit 60 The variable throttle valve 71 is maintained at a predetermined position (for example, a fully open position), the throttle amount of the variable throttle mechanism 71 is constant, and the amount of argon supplied to the combustion chamber 11 is constant.

  On the other hand, when the required torque is greater than the first predetermined torque Tq1, the electronic control unit 60 controls the variable throttle mechanism 71 to relatively increase the throttle amount and relatively reduce the passage opening of the circulation path 20. By doing so, the amount of argon supplied to the combustion chamber 11 is reduced. In this case, the electronic control unit 60 reduces the amount of argon supplied to the combustion chamber 11 as the required torque increases. That is, in this case, for example, in the engine 1, the amount of hydrogen and oxygen supplied to the combustion chamber 11 increases as the required torque increases, while the amount of argon supplied to the combustion chamber 11 decreases.

  As a result, as illustrated in FIG. 3, the engine 1 reduces the amount of argon present in the combustion chamber 11 at the start of compression in the combustion chamber 11 in an operation state where the required torque is greater than the first predetermined torque Tq1. Therefore, it is possible to suppress the compression end pressure from being lowered and the maximum in-cylinder pressure from becoming too large, and it can be maintained substantially constant. Therefore, the engine 1 can adjust the pressure in the combustion chamber 11 to an appropriate pressure. For example, the engine 1 can be adjusted to a suitable pressure according to the operating state within an allowable range according to the strength and specifications of the engine body 10. can do. In FIG. 3, the solid line L1 represents the maximum in-cylinder pressure in the engine 1 of the present embodiment that executes the argon reduction control, while the dotted line L2 represents the maximum in-cylinder pressure in the engine according to the comparative example that does not execute the argon reduction control. To express.

  Further, since the engine 1 can suppress the pressure in the combustion chamber 11 from becoming too large, for example, a cylinder head that constitutes the engine body 10 against an excessive increase in the pressure in the combustion chamber 11, There is no need to secure further pressure resistance by increasing the pressure resistance of structural members such as cylinder blocks. Therefore, since the engine 1 can suppress an increase in size and an increase in weight, it is possible to suppress deterioration in mountability on a vehicle and suppress an increase in manufacturing cost.

  Next, an example of control in the engine 1 will be described with reference to the flowchart of FIG. Note that these control routines are repeatedly executed at a control cycle of several ms to several tens of ms.

  First, the electronic control unit 60 acquires a required torque that is determined according to the accelerator opening and the engine speed based on the detection results of the accelerator opening sensor 61 and the crank angle sensor 62 (ST1).

  Next, the electronic control unit 60 determines whether or not the required torque acquired in ST1 is larger than a first predetermined torque Tq1 set in advance (ST2).

  When it is determined that the required torque is greater than the first predetermined torque Tq1 (ST2: Yes), the electronic control unit 60 controls the variable throttle mechanism 71 and compares it with the case where the argon reduction control is not performed (that is, the required torque). Is smaller than the first predetermined torque Tq1), the amount of argon supplied to the combustion chamber 11 is reduced by reducing the variable throttle according to the required torque (ST3), and the current control cycle is ended. Then, the next control cycle is started.

  When it is determined that the required torque is equal to or less than the first predetermined torque Tq1 (ST2: No), the electronic control unit 60 controls the variable throttle mechanism 71 to open the variable throttle and maintain it at a predetermined opening degree. The amount of argon supplied to is fixed (ST4), the current control cycle is terminated, and the next control cycle is started.

  According to the engine 1 according to the embodiment of the present invention described above, hydrogen and argon having a specific heat ratio higher than that of air are supplied, and the combustion chamber 11 in which argon can expand with combustion of hydrogen is included. A circulation path 20 that can circulate gas from the exhaust side to the intake side of the combustion chamber 11 and supply it to the combustion chamber 11 again, and an adjustment mechanism that is provided in the circulation path 20 and that can adjust the amount of argon supplied to the combustion chamber 11. 70, and when the required torque is greater than a preset first predetermined torque Tq1, the adjustment mechanism 70 is controlled to reduce the amount of working gas supplied to the combustion chamber 11 as the required torque increases. An electronic control unit 60. Therefore, for example, the engine 1 can suppress the pressure in the combustion chamber 11 from becoming too large, and can adjust the pressure in the combustion chamber 11 to an appropriate pressure.

[Embodiment 2]
FIG. 5 is a schematic schematic configuration diagram of an engine according to the second embodiment. The working gas circulation engine according to the second embodiment is different from the working gas circulation engine according to the first embodiment in the position of the variable throttle mechanism. In addition, about the structure, effect | action, and effect which are common in embodiment mentioned above, while overlapping description is abbreviate | omitted as much as possible, the same code | symbol is attached | subjected (the following embodiment is also the same).

  An engine 201 as a working gas circulation engine of the present embodiment shown in FIG. 5 includes an adjustment mechanism 70, and the adjustment mechanism 70 has a variable throttle mechanism 71.

  Then, the variable throttle mechanism 71 of the present embodiment is configured to supply a supply position of hydrogen or oxygen with respect to the circulation direction of the circulating gas in the circulation path 20 with reference to the combustion chamber 11, in this case, oxygen supplied with oxygen. Provided upstream from the supply position. The variable throttle mechanism 71 is provided between the oxygen supply position and the exhaust side of the combustion chamber 11. The variable throttle mechanism 71 is supplied to the combustion chamber 11 by driving a variable throttle valve provided in the circulation path 20 and adjusting the throttle amount of the passage between the oxygen supply position and the exhaust side of the combustion chamber 11. The amount of argon can be adjusted.

  In this case, the engine 201 is supplied to the combustion chamber 11 by the variable throttle mechanism 71 by providing the variable throttle mechanism 71 upstream of the oxygen supply position with respect to the circulation chamber with respect to the circulation direction. It is not necessary to adjust the amount of oxygen to be adjusted, and only the amount of argon supplied to the combustion chamber 11 can be adjusted. Thereby, the engine 201 can improve the controllability of engine control, for example, can improve the responsiveness at the time of engine output transition. In other words, the engine 201 does not change the amount of oxygen supplied to the combustion chamber 11 even if the amount of argon supplied to the combustion chamber 11 by the variable throttle mechanism 71 is changed. Only the amount of argon supplied to the chamber 11 can be easily adjusted, and the pressure in the combustion chamber 11 can be easily adjusted to a suitable pressure corresponding to the operating state within an allowable range.

  According to the engine 201 according to the embodiment of the present invention described above, the variable throttle mechanism 71 burns hydrogen or hydrogen with reference to the combustion chamber 11 with respect to the circulation direction of the gas circulated in the circulation path 20. It is provided upstream from the supply position where oxygen is supplied. Therefore, the engine 201 can improve the controllability of engine control.

[Embodiment 3]
FIG. 6 is a schematic schematic configuration diagram of an engine according to the third embodiment, and FIG. 7 is a flowchart illustrating an example of control in the engine according to the third embodiment. The working gas circulation engine according to the third embodiment is different from the working gas circulation engine according to the first embodiment in the configuration of the adjusting mechanism.

  The engine 301 as the working gas circulation engine of this embodiment shown in FIG. 6 includes an adjustment mechanism 370, and the adjustment mechanism 370 includes a valve mechanism 372. The valve operating mechanism 372 can adjust the opening / closing operation of the intake valve 14 that can open and close the intake port 12 communicating with the combustion chamber 11. The valve operating mechanism 372 adjusts the amount of gas sucked into the combustion chamber 11 by changing the lift amount and opening / closing timing of the intake valve 14 provided in the intake port 12 and changing them continuously. The valve operating mechanism 372 reduces the amount of argon supplied to the combustion chamber 11 by relatively retarding the closing timing of the intake valve 14 or relatively reducing the lift amount of the intake valve 14. can do. When the engine 301 relatively delays the closing timing of the intake valve 14, for example, the intake valve 14 is closed in the middle of the piston 16 past the bottom dead center toward the top dead center. Thus, the amount of argon supplied to the combustion chamber 11 can be reduced. On the other hand, the valve operating mechanism 372 relatively advances the valve closing timing of the intake valve 14 or relatively increases the lift amount of the intake valve 14 to thereby increase the amount of argon supplied to the combustion chamber 11. Can be increased. The valve operating mechanism 372 is electrically connected to the electronic control device 60 or connected via a hydraulic control circuit or the like, and its drive is controlled.

  Next, an example of control in the engine 301 will be described with reference to the flowchart of FIG.

  When it is determined that the required torque is greater than the first predetermined torque Tq1 (ST2: Yes), the electronic control unit 60 controls the valve mechanism 372 and compares it with the case where the argon reduction control is not performed (that is, the required torque). Is relatively retarded or the lift amount of the intake valve 14 is made relatively small according to the required torque. Alternatively, both are performed to reduce the amount of argon supplied to the combustion chamber 11 (ST33), the current control cycle is terminated, and the next control cycle is started.

  When the electronic control unit 60 determines that the required torque is equal to or less than the first predetermined torque Tq1 (ST2: No), the electronic control unit 60 controls the valve mechanism 372 to relatively set the closing timing of the intake valve 14 according to the required torque. Is advanced, or the lift amount of the intake valve 14 is relatively increased, or both are performed to increase the amount of argon supplied to the combustion chamber 11 (ST34), and the current control cycle ends. Then, the next control cycle is started.

  In this case, the engine 301 can adjust the amount of argon supplied to the combustion chamber 11 by the valve operating mechanism 372 without providing the variable throttle mechanism 71 described above. The engine 301 adjusts the amount of argon supplied to the combustion chamber 11 by the opening / closing operation of the intake valve 14 disposed at a position closer to the combustion chamber 11, so that the amount of argon is accurately and responsive. For example, it is possible to further improve the controllability and responsiveness of engine control during transient operation.

  According to the engine 301 according to the embodiment of the present invention described above, the adjusting mechanism 370 includes the valve operating mechanism 372 that can adjust the opening / closing operation of the intake valve 14 that can open and close the intake port 12 communicating with the combustion chamber 11. Have. Therefore, the engine 301 can further improve the controllability of engine control.

[Embodiment 4]
FIG. 8 is a diagram for explaining oxygen increase control of the engine according to the fourth embodiment, FIG. 9 is a flowchart for explaining an example of control in the engine according to the fourth embodiment, and FIG. 10 is in the engine according to the fourth embodiment. It is an example of a control map. The working gas circulation engine according to the fourth embodiment is different from the working gas circulation engine according to the first embodiment in that oxidant increase control is executed in addition to working gas reduction control.

  The engine 401 as the working gas circulation engine of the present embodiment described in FIGS. 8 to 10 is configured so that the supply amount of oxygen (oxidant) supplied to the combustion chamber 11 by the electronic control unit 60 under a predetermined condition. By executing increasing oxygen (oxidant) increase control, the pressure in the combustion chamber 11 is adjusted to a more appropriate pressure.

  As illustrated in FIG. 8, the electronic control device 60 according to the present embodiment performs oxygen supply as oxygen increase control when the required torque required for the engine 401 is greater than a preset second predetermined torque Tq2. The apparatus 30 is controlled to adjust the supply amount of oxygen for burning the hydrogen supplied to the combustion chamber 11 to a supply amount larger than the supply amount corresponding to the theoretical ratio of combustion with hydrogen.

  Here, the second predetermined torque Tq2 is a torque at which the in-cylinder pressure, which is the pressure in the combustion chamber 11, becomes a predetermined pressure set in advance, and is set in advance based on experiments or the like. More specifically, the second predetermined torque Tq2 and the predetermined pressure are obtained by executing the above-described oxygen increase control so that the maximum in-cylinder pressure, which is the maximum in-cylinder pressure in the combustion chamber 11, becomes the strength and specifications of the engine main body 10 Is set to fall within an allowable range set in advance. The second predetermined torque Tq2 may be equal to or different from the first predetermined torque Tq1 described above.

  In the normal control, the electronic control unit 60 is operated at the current engine speed from a supply amount map (not shown) stored in advance in the storage unit, for example, according to the operation state such as the accelerator opening and the engine speed. The supply amount and supply timing of hydrogen and oxygen capable of obtaining the required torque are determined. In this case, the supply amount of hydrogen and the supply amount of oxygen are set to have a theoretical ratio. Here, the supply amount of oxygen according to the theoretical ratio of the reaction with hydrogen in the combustion chamber 11 is a supply amount capable of burning an amount of hydrogen determined to obtain the required torque without excess or deficiency. The supply amount of oxygen according to the theoretical ratio of the reaction with hydrogen in the combustion chamber 11 is typically a supply amount of a half in a molar ratio with respect to the supply amount of hydrogen determined as described above. It is.

  On the other hand, in the oxygen increase control, the electronic control unit 60 increases and corrects the oxygen supply amount to a supply amount obtained by adding a predetermined amount to the oxygen supply amount corresponding to the theoretical ratio. As a result, in the engine 401, in the oxygen increase control, a predetermined amount of oxygen remains in the exhaust gas after the combustion of hydrogen in the combustion chamber 11. As a result, the engine 401 can reduce the specific heat ratio of the circulating gas supplied to the combustion chamber 11 according to the amount of oxygen that is increased and remains, and the maximum in-cylinder pressure becomes too large. It can suppress more reliably.

  Next, an example of control in the engine 401 will be described with reference to the flowchart of FIG.

  First, the electronic control unit 60 acquires a required torque that is determined according to the accelerator opening and the engine speed based on the detection results of the accelerator opening sensor 61 and the crank angle sensor 62 (ST41).

  Next, the electronic control unit 60 determines the required oxygen injection amount TAUO2req as the supply amount of oxygen supplied from the oxygen supply device 30 based on the required torque acquired in ST41 (ST42).

  Here, the electronic control unit 60 obtains the required oxygen injection amount TAUO2req based on, for example, the control map illustrated in FIG. In this control map, the horizontal axis indicates the required torque, and the vertical axis indicates the required oxygen injection amount. The control map describes the relationship between the required torque and the required oxygen injection amount. In this control map, the basic required oxygen injection amount indicated by the dotted line A in the figure increases as the required torque increases. This basic required oxygen injection amount is the supply amount of oxygen corresponding to the theoretical ratio of the reaction with hydrogen in the combustion chamber 11 described above. Further, the required oxygen injection amount after the increase correction of the predetermined amount α shown by the solid line B in the figure branches from the dotted line A representing the basic required oxygen injection amount at the second predetermined torque Tq2, and increases as the required torque increases. To do. Here, the predetermined amount α increases as the required torque increases. The control map is stored in the storage unit of the electronic control device 60 after the relationship between the required torque and the required oxygen injection amount is set in advance.

  In ST42, the electronic control unit 60 obtains the required oxygen injection amount TAUO2req from the required torque acquired in ST41 and the dotted line A representing the basic required oxygen injection amount based on the control map of FIG. In the present embodiment, the electronic control unit 60 calculates the required oxygen injection amount using the control map illustrated in FIG. 10, but the present embodiment is not limited to this. For example, the electronic control unit 60 may obtain the required oxygen injection amount based on a mathematical expression corresponding to the control map illustrated in FIG.

  Next, the electronic control unit 60 determines whether or not the required torque acquired in ST41 is greater than a second predetermined torque Tq2 set in advance (ST43).

  When the electronic control unit 60 determines that the required torque is greater than the second predetermined torque Tq2 (ST43: Yes), the required torque acquired in ST41 and the required oxygen injection after the increase correction based on the control map of FIG. A required oxygen injection amount TAUO2req is calculated from the solid line B representing the amount, with an increase correction of a predetermined amount α. Then, the electronic control unit 60 controls the oxygen supply unit 30 to inject and supply oxygen of the required oxygen injection amount TAUO2req taking into account the increase correction of the predetermined amount α into the circulation path 20 (ST44). End the cycle and move to the next control cycle.

  When the electronic control unit 60 determines that the required torque is equal to or less than the second predetermined torque Tq2 (ST43: No), the electronic control unit 60 controls the oxygen supply device 30 to obtain the oxygen of the basic required oxygen injection amount TAUO2req obtained in ST42. The fuel is injected and supplied to the circulation path 20 (ST45), the current control cycle is terminated, and the next control cycle is started.

  According to the engine 401 according to the embodiment of the present invention described above, the electronic control unit 60 allows the hydrogen supplied to the combustion chamber 11 when the required torque is larger than the second predetermined torque Tq2 set in advance. The supply amount of oxygen for burning is controlled to a supply amount larger than the supply amount corresponding to the theoretical ratio of combustion with hydrogen. Accordingly, since the engine 401 has a predetermined amount of oxygen remaining in the exhaust gas after the combustion of hydrogen in the combustion chamber 11, for example, the pressure in the combustion chamber 11 can be more reliably increased. Therefore, the pressure in the combustion chamber 11 can be adjusted to a more appropriate pressure.

  The working gas circulation engine according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. The working gas circulation engine according to the embodiment of the present invention may be configured by combining a plurality of the embodiments described above.

  The working gas circulation engine described above has been described on the assumption that the oxidant is oxygen and the fuel is hydrogen. However, the working gas is not limited to this, and the working gas may be expanded as the fuel is burned in the combustion chamber. Anything is possible. The working gas described above is not limited to argon, but may be a rare gas such as helium (He) which is a monoatomic gas.

  As described above, the working gas circulation engine according to the present invention is suitable for application to various working gas circulation engines capable of circulating the working gas from the exhaust side to the intake side of the combustion chamber and supplying the working gas to the combustion chamber again. .

1, 201, 301, 401 Engine (working gas circulation engine)
DESCRIPTION OF SYMBOLS 10 Engine body 11 Combustion chamber 12 Intake port 13 Exhaust port 14 Intake valve 15 Exhaust valve 20 Circulation path 30 Oxygen supply device 40 Hydrogen supply device 50 Condenser 60 Electronic control device (control device)
61 Accelerator opening sensor 62 Crank angle sensor 70, 370 Adjustment mechanism 71 Variable throttle mechanism 372 Valve mechanism

Claims (6)

A combustion chamber in which a working gas having a specific heat ratio higher than that of air and air is supplied and the working gas can expand as the fuel burns;
A circulation path through which the gas containing the working gas is circulated from the exhaust side to the intake side of the combustion chamber and can be supplied to the combustion chamber again;
An adjusting mechanism provided in the circulation path and capable of adjusting the amount of the working gas supplied to the combustion chamber;
A control device that controls the adjusting mechanism to reduce the amount of the working gas supplied to the combustion chamber in accordance with an increase in the required torque when a required torque is greater than a first predetermined torque set in advance. Characterized by comprising
Working gas circulation engine. The first predetermined torque is a torque at which the pressure in the combustion chamber becomes a predetermined pressure set in advance.
The working gas circulation engine according to claim 1. The adjustment mechanism has a variable throttle mechanism that makes the cross-sectional area of the circulation path variable.
The working gas circulation engine according to claim 1 or 2. The variable throttle mechanism is provided upstream of a supply position to which the fuel or an oxidant for burning the fuel is supplied with respect to the direction of circulation of the circulating gas in the circulation path with reference to the combustion chamber. ,
The working gas circulation engine according to claim 3. The adjusting mechanism has a valve operating mechanism capable of adjusting an opening / closing operation of an intake valve capable of opening / closing an intake port communicating with the combustion chamber.
The working gas circulation engine according to any one of claims 1 to 4. When the required torque is larger than a second predetermined torque set in advance, the control device sets a supply amount of an oxidant that burns the fuel supplied to the combustion chamber to the theory of combustion with the fuel. Control the supply amount higher than the supply amount according to the ratio,
The working gas circulation engine according to any one of claims 1 to 5.

Images