JP5271961B2 - Supercharger for internal combustion engine - Google Patents

Description

  The present invention uses the heat energy of the exhaust gas of the internal combustion engine and the cooling water heat of the internal combustion engine to convert it into electric energy, and drives the electric motor of the hybrid supercharger using the electric energy to supply the electric energy. The present invention relates to a supercharging device for an internal combustion engine that increases the air pressure, and more particularly to a supercharging device suitable for a Miller cycle internal combustion engine.

The mirror cycle in a four-cycle engine avoids knocking and achieves high thermal efficiency by closing the intake valve earlier or later than bottom dead center to keep the compression ratio of the internal combustion engine smaller than the expansion ratio. It is effective for.
The Miller cycle is also known to realize a large expansion ratio and sufficiently expand the combustion gas so that the combustion energy can be utilized more effectively as torque.

  A PV diagram indicated by a solid line in FIG. 7 is a PV diagram of an internal combustion engine with a supercharger, and shows a mirror cycle in which an air supply is quickly closed based on an Otto cycle. It consists of a compression stroke (M1), a combustion / expansion step (M2), an exhaust stroke (M3), and an air supply stroke (M4). By closing the air supply valve at a point earlier than the bottom dead center at the point P of the air supply stroke, the air expands along the line m1 from the point P, returns along the line m1, and compresses again, and then compresses from the point P. It changes along the line of the stroke (M1).

  As a result, as shown in the lower part of FIG. 7, the piston stroke of the combustion chamber volume used for calculating the compression ratio is A1, the piston stroke of the combustion chamber volume used for calculating the expansion ratio is A2, and the compression ratio is set to the expansion ratio. It can be made smaller.

  Here, when the improvement of thermal efficiency is considered with respect to the current mirror cycle for quick closing of the supply air shown by the solid line in FIG. 7, the supply stroke (M4) and the exhaust stroke (M3) are performed by the supply air pressurization by the supercharger. ) Formed in the clockwise bag-like closed loop of M3 to M4 (shaded area in FIG. 7) forms a pumping work showing a positive work amount with respect to the internal combustion engine. It is effective to improve the thermal efficiency.

However, if the boost pressure is increased to increase the supply stroke (M4) in order to improve the pumping work, the exhaust pressure, which is the drive source of the turbocharger, needs to be increased. The pumping work to be done is not significantly improved compared to before boosting the supercharging pressure.
(The hatched area in FIG. 7 is only shifted upward (h).)
Further, just increasing the supercharging pressure causes the exhaust pressure to increase in the same manner, increasing the entire PV diagram (dotted line in FIG. 7) as shown in FIG. 7, and increasing the in-cylinder maximum pressure (Pmax). To rise.
As a result, the allowable maximum pressure may be exceeded, which adversely affects the mechanical strength and heat load of the internal combustion engine body.

On the other hand, Patent Document 1 (Japanese Patent Laid-Open No. 7-305606) and Patent Document 2 (Japanese Patent Laid-Open No. 2000-220480) are known as inventions related to the mirror cycle engine.
As shown in FIG. 8, the configuration disclosed in Patent Document 1 connects an exhaust gas supply pipe 03 from a mirror cycle gas engine 01 to a steam generator 05, and a working fluid circulation pipe connected to the steam generator 05. A steam turbine 09 is provided at 07, a supercharger 013 for supplying compressed air to the Miller cycle gas engine 01 is provided at an output shaft 011 of the steam turbine 09, and the combustion exhaust gas from the Miller cycle gas engine 01 is used as a heat source. The feeder 013 is driven to improve the internal combustion engine output.

  Patent Document 2 discloses a Miller cycle engine provided with a two-stage supercharger in series. Furthermore, an invention is shown in which exhaust gas recirculation (EGR) is employed in this Miller cycle engine to achieve high fuel efficiency while suppressing knocking.

JP-A-7-305606 JP 2000-220480 A

However, Patent Documents 1 and 2 do not disclose a technique for improving the thermal efficiency by increasing the pumping work formed by the exhaust stroke and the intake stroke in the mirror cycle engine.
Furthermore, as already described with reference to FIG. 7, simply increasing the supercharging pressure of the supercharger not only does not improve the thermal efficiency due to the pumping work, but also increases the in-cylinder maximum pressure (Pmax). Therefore, there is also a problem that an adverse effect occurs in the mechanical strength and heat load of the internal combustion engine body.

  Therefore, the present invention has been made in view of the above-described problems, and generates a steam by using the hot water on the internal combustion engine side or the thermal energy of the exhaust gas, and generates the hybrid by the electric power of the generator equipped with the steam turbine. Drives the electric motor of the turbocharger to increase the supply pressure without increasing the exhaust pressure, and sets the supply pressure to the upper limit of the supply pressure at which the in-cylinder maximum pressure of the internal combustion engine is less than the allowable value The internal combustion engine which improves the efficiency (increase in output) of the internal combustion engine, the smoke color improvement (combustion improvement) accompanying the increase in the air amount, the mechanical strength of the internal combustion engine body and the reliability against the heat load An object of the present invention is to provide a supercharging device.

The present invention achieves such an object, and an exhaust turbine driven by exhaust gas of an internal combustion engine, an electric motor driven by supply of electric power, and driving force of the exhaust turbine and the electric motor to the internal combustion engine. A hybrid turbocharger including a compressor for pressurizing supply air; a steam turbine driven by steam generated by utilizing exhaust heat of the internal combustion engine; and a generator for generating electric power by driving the steam turbine; the provided, the electric power generated by the generator possess the power supply supplied to the hybrid turbocharger, the power supply device further the exhaust passing through the exhaust turbine of the hybrid turbocharger Provided in an evaporator that generates the steam using exhaust heat of gas, and an exhaust system circuit between the hybrid supercharger and the evaporator; A second heat exchanger for heating the exhaust gas with steam from a boiler device provided separately from the internal combustion engine, a second bypass circuit provided in parallel with the second heat exchanger, and the second bypass circuit And a second flow rate adjusting valve that is adjusted in flow rate by a control device .

According to the above-described supercharging device for an internal combustion engine, the exhaust turbine of the hybrid supercharger is driven by the exhaust gas of the internal combustion engine. Further, steam is generated by using heat energy such as cooling water after cooling the internal combustion engine and exhaust gas of the internal combustion engine, and the steam is driven by the steam to convert it into electricity, and the electricity is hybrid supercharged. The turbocharger is driven by supplying to the electric motor of the machine. As a result, the supply pressure of the internal combustion engine can be increased without increasing the pressure of the exhaust gas of the internal combustion engine, and the output of the internal combustion engine can be improved by improving the pumping work formed by the exhaust stroke and the supply stroke. It is possible to improve fuel economy and smoke color.
Further, according to the supercharging device for an internal combustion engine described above, when the boiler device is installed, the exhaust gas is heated by the steam heat of the boiler, and the generated steam amount of the evaporator is adjusted to the second flow rate. By adjusting with the valve and adjusting the amount of power generated by the turbine, the supply pressure at the hybrid supercharger can be increased to effectively increase the internal combustion engine output.

  Further, a preferred aspect of the above-described supercharging device for the internal combustion engine includes a pressure detection device that detects a pressure of the supply air pressurized by the hybrid supercharger, and the internal combustion engine based on a detection result of the pressure detection device. And a control device that controls the amount of power supplied to the hybrid supercharger so that the maximum in-cylinder pressure becomes an air supply pressure that is equal to or lower than an allowable value.

  With such a configuration, the amount of power supplied to the hybrid supercharger is controlled so that the maximum cylinder pressure of the internal combustion engine becomes a permissible pressure or less. Strength and reliability against heat load can be improved.

Also preferably in the present invention, the evaporator, the condenser to condense the steam having driven the steam turbine and, working medium having a water supply means for water and condensed water which has been condensed in the condenser to the evaporator And a playback device.

  With such a configuration, the working medium is circulated and used, so that an increase in cost can be suppressed.

  Preferably, in the present invention, the power supply device is provided on the upstream side of the evaporator, and heats the condensed water condensed by the condenser with cooling water that has cooled the internal combustion engine. It is good to have a exchanger, the 1st bypass circuit provided in parallel with this 1st heat exchanger, and the 1st flow control valve provided in this 1st bypass circuit, and the flow control of which is carried out by the control device.

With this configuration, the working medium is heated with the cooling water of the internal combustion engine, so that exhaust heat from the internal combustion engine can be used effectively, and a load on the internal combustion engine side for increasing the supply air pressure is required. Therefore, the output of the internal combustion engine can be increased efficiently.
In addition, since the first flow rate adjusting valve is provided to adjust the coolant flow rate to the first heat exchanger, the amount of steam generated in the evaporator can be adjusted to control the amount of power generated in the generator.

  Preferably, in the present invention, the power supply device is provided between the evaporator and the working medium regenerator, and a third bypass circuit in which the working medium flows in parallel with the steam turbine; It is good to have a 3rd flow rate adjustment valve provided in a bypass circuit, and the flow rate of which is adjusted by the control device.

With this configuration, the amount of power generated by the generator can be controlled by adjusting the flow rate of the working medium flowing through the turbine with the third flow rate adjustment valve.
In addition, it is easy to control the power supplied to the electric motor of the hybrid turbocharger so that the maximum pressure in the cylinder of the internal combustion engine is less than the allowable value. Can do.

  In the present invention, preferably, the power supply device includes a fourth flow rate adjustment valve interposed between the water supply means and the evaporator, and the flow rate of which is adjusted by the control device.

  With this configuration, the medium flow rate to the evaporator is adjusted by the fourth flow rate adjustment valve, and the generated steam amount is adjusted, thereby controlling the generated power of the generator and the hybrid turbocharger. It is possible to effectively increase the output of the internal combustion engine by controlling the air supply pressure.

  Preferably, in the invention of the present application, the power supply device bypasses the exhaust turbine of the hybrid supercharger and bypasses the exhaust gas discharged from the internal combustion engine to supply the evaporator. An exhaust gas bypass valve whose flow rate is adjusted by the control device may be included in the fourth bypass circuit.

By adopting such a configuration, the opening of the exhaust gas bypass valve is fixed to an arbitrary opening, and the supply air pressure is controlled by the drive control of the electric motor. Since the air-fuel ratio between the gas and the fuel is required to be appropriate, it is easy to control the supply air pressure along the load fluctuation of the internal combustion engine, and the gas engine has the effect of easily improving the engine efficiency. .
The exhaust pressure at the turbocharger inlet can be reduced by increasing the amount of bypass to the exhaust gas bypass valve. Therefore, the pumping work formed by the supply stroke and the exhaust stroke can be increased.

  Preferably, in the present invention, the internal combustion engine is a Miller cycle engine that closes an air supply valve earlier or later than bottom dead center to make a compression ratio smaller than an expansion ratio, and the air supply valve has an opening / closing timing. It has a variable air supply valve that can be changed freely.

By applying it to the Miller cycle engine in this way, the smoke color of the exhaust gas can be improved by improving the output of the internal combustion engine accompanying the increase of the supply air pressure and improving the combustion accompanying the increase of the supply air amount without increasing the exhaust pressure. Figured.
Furthermore, since it becomes possible to increase the supply pressure without increasing the exhaust pressure, the pumping work formed by the exhaust stroke and the supply stroke is increased in the mirror cycle engine, thereby improving the thermal efficiency. Can be obtained effectively.

According to the present invention, steam is generated using the hot water on the internal combustion engine side or the thermal energy of the exhaust gas, and the hybrid turbocharger is driven by the electric power of the generator provided with the steam turbine to supply the air By controlling the pressure so that the supply pressure at which the maximum in-cylinder pressure of the internal combustion engine is below the allowable value is the upper limit, the efficiency of the internal combustion engine (improvement of output) and the smoke color improvement (combustion improvement) associated with the increase in air volume ) And the mechanical strength of the internal combustion engine body and the reliability against the heat load can be improved.
According to the present invention, the second heat exchanger is provided in the exhaust system circuit between the hybrid supercharger and the evaporator, and heats the exhaust gas with steam from a boiler device provided separately from the internal combustion engine. And a second bypass circuit provided in parallel with the second heat exchanger, and a second flow rate regulating valve provided in the second bypass circuit and regulated by a control device, thereby generating an evaporator. The amount of steam can be adjusted with the second flow rate adjustment valve to adjust the amount of power generated by the turbine, and the supply pressure at the hybrid supercharger can be increased to effectively increase the output of the internal combustion engine.

FIG. 1 is a schematic configuration diagram of a mirror cycle engine according to a first embodiment of the present invention. FIG. 2 is a schematic overall configuration diagram of the hybrid supercharging device according to the embodiment of the present invention. FIG. 3 is a PV diagram for explaining the present invention. FIG. 4 shows a PV diagram illustrating the mirror cycle of the present invention. FIG. 5 shows a supply air pressure control flow chart according to the first embodiment of the present invention. FIG. 6 shows a supply air pressure control flow chart of the gas engine according to the second embodiment of the present invention. FIG. 7 is a PV diagram illustrating a conventional mirror cycle. FIG. 8 is an explanatory diagram of the prior art.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specifically described. Only.

(First embodiment)
FIG. 1 is a schematic overall configuration diagram of a hybrid supercharging device for a Miller cycle engine (hereinafter collectively referred to as an internal combustion engine) according to an embodiment of the present invention.
In FIG. 1, the internal combustion engine 1 is described as a four-cycle engine as an example.
The cylinder 11 of the main body of the internal combustion engine 1 includes a piston 12 slidably fitted in a reciprocating manner, and a crankshaft (not shown) that converts the reciprocating motion of the piston 12 into rotation through a connecting rod (not shown). Further, an exhaust port 16 connected to the combustion chamber 15 and an exhaust valve 14 for opening and closing the exhaust port 16 are provided. The exhaust port 16 is connected to the exhaust turbine 22 of the hybrid supercharger 2 via the exhaust passage L1.

Compressed air from the hybrid supercharger 2 is supplied to the air supply port 17 via the air supply passage L2, and an air cooler 25 is provided in the air supply passage L2. The pressurized supply air cooled by the air cooler 25 is supplied to the combustion chamber 15 through the supply port 17 and the supply valve 13.
The air supply valve 13 is equipped with an air supply valve variable means 92 that opens and closes based on a signal from the valve opening / closing timing control means 91 of the control device 9.

  FIG. 2 shows a schematic overall configuration diagram of the hybrid supercharger, in which exhaust gas discharged from the internal combustion engine 1 is connected to an exhaust turbine 22 of the hybrid supercharger 2 via an exhaust passage. The hybrid supercharger 2 is supported coaxially with the exhaust turbine 22 and has a compressor 21 that generates pressurized air supply by the driving force of the exhaust turbine 22. Further, an electric motor 23 is connected to the compressor 21, and the compressor 21 is driven by electric power from the power supply device 4 described later to further pressurize the pressurized air.

The power supply device 4 is located on the downstream side of the exhaust system of the exhaust turbine 22 of the hybrid turbocharger 2 and heats the exhaust gas with steam of a boiler device provided separately from the internal combustion engine 1 when the exhaust gas heat is low. The second heat exchanger 7 and a liquid working medium that is located downstream of the exhaust system of the second heat exchanger 7 and generates power from the generator 3 described later with the exhaust gas heat that has passed through the second heat exchanger 7 (low Driven by the steam, the evaporator 5 that converts a boiling point liquid (for example, chlorofluorocarbon) into steam, the first heat exchanger 41 that heats the liquid working medium to be sent to the evaporator 5 with the cooling water heat of the internal combustion engine 1, and the steam The generator 3 is provided with a steam turbine 31 and the working medium regenerator 6 for liquefying the vaporized working medium again.
The exhaust gas that has passed through the evaporator 5 is detoxified with harmful components and released into the atmosphere.

  The working medium regenerator 6 heats the working medium that has passed through the steam turbine 31 of the generator 3 and heats the liquid working medium sent to the first heat exchanger 41. The condenser 62 that cools and liquefies the steam, which is the working medium, the receiver 63 that stores the liquefied working medium and removes dust and moisture, and the circulation pump that is the water supply means for sending the working medium of the receiver 63 64 and a fourth flow rate adjusting valve 65 that adjusts the amount of working medium delivered according to the amount of steam generated (power generation amount).

By heating the liquid working medium sent to the first heat exchanger 41 by the economizer 61, the temperature of the working medium in the first heat exchanger 41 is further increased, and steam is generated in the evaporator 5. The amount can be increased.
On the other hand, the steam discharged from the steam turbine 31 of the generator 3 is cooled by heating the liquid working medium sent to the first heat exchanger 41 by the economizer 61, thereby promoting the condensation of steam and the condenser 62. The action of cooling and condensing the steam of the generator 3 has the effect of increasing the pressure difference between the upstream and downstream of the steam turbine 31 of the generator 3 to increase the power generation output.

The first heat exchanger 41 is provided with a first bypass circuit 43 that bypasses the cooling water of the internal combustion engine 1, and a first flow rate adjustment valve 42 that adjusts the flow rate of the cooling water at an intermediate portion of the first bypass circuit 43. Is arranged. The first flow rate adjustment valve 42 adjusts the amount of cooling water of the internal combustion engine that flows in the first heat exchanger 41 so that the evaporator 5 generates an evaporation amount corresponding to the required power generation amount in the generator 3. Adjust the heating of the working refrigerant by the flow rate of the engine cooling water.
The second heat exchanger 7 heats the exhaust gas flowing in the exhaust gas passage 73 piped in the second heat exchanger 7 by receiving steam heat from a separately disposed boiler.
The second heat exchanger 7 is provided with a second bypass circuit 71 for bypassing the exhaust gas in parallel with the second heat exchanger 7, and the flow rate of the exhaust gas flowing through the second heat exchanger 7 is set in the middle part. A second flow rate adjustment valve 72 to be adjusted is disposed.

In order to cause the evaporator 5 to generate an evaporation amount corresponding to the required power generation amount in the generator 3, the amount of exhaust gas heated by the boiler steam is adjusted.
Furthermore, the 3rd bypass circuit 52 which distribute | circulates the steam from the evaporator 5 in parallel with the steam turbine 31 of the generator 3 is provided, and the quantity which flows into the steam turbine 31 side of this working medium (steam) in this 3rd bypass circuit 52 A third flow rate adjusting valve 51 for adjusting the amount of power generated by the generator 3 is adjusted.
Since the amount of the working medium (steam) flowing on the steam turbine 31 side can be directly adjusted as the amount of power generation, this third flow rate adjustment valve 51 has an effect that it is easy to quickly respond to the supply pressure adjustment. .

The electric power generated by the generator 3 is supplied to the electric motor 23 connected to the compressor 21 of the hybrid turbocharger 2 and is pressurized by the driving force of the electric motor 23 in addition to the driving force of the exhaust turbine. The supply air is discharged from the compressor 21. The discharged supply air is cooled by the air cooler 25 and supplied into the cylinder 11 of the internal combustion engine 1.
Since the pressurized supply air has a high supply air temperature, the air density is low, and a sufficient amount of air for the operation of the internal combustion engine 1 cannot be supplied.
Therefore, in order to supply a sufficient amount of air to the internal combustion engine 1, the air supply pressurized by the air cooler 25 is cooled to increase the air density.
Further, an air supply pressure sensor 26 that is a pressure detection device for measuring the air supply pressure is disposed downstream of the air cooler 25, and the detected pressure is transmitted to the control device 9.

The control device 9 controls the power to be supplied to the hybrid supercharger 2 by controlling the valve opening / closing timing control means 91 having a valve closing timing control map of the air supply valve 13 and the generated power of the generator 3, Power supply control means 93 for adjusting the supply air pressure.
The valve opening / closing timing control means 91 is controlled based on a valve closing timing control means 92 (based on a valve closing timing control map in which the valve closing timing of the air supply valve 13 corresponding to the air supply pressure detected by the air supply pressure sensor 26 is set. 1) is activated.

As shown in FIG. 3, the exhaust pressure Ph during the exhaust stroke (M3) and the intake pressure Pk during the intake stroke (M4) formed by the hybrid turbocharger 2 are An increase ΔP of the supply air pressure that is additionally pressurized by the electric motor 23 is added to obtain the pressure during the supply stroke (M4).
Accordingly, the total supply pressure (Pk + ΔP) of the supply pressure Pk by the exhaust gas of the hybrid supercharger 2 and the additional supply pressure ΔP by the electric motor 23 is detected by the supply pressure sensor 26, and based on this detected value. Thus, the closing timing of the air supply valve 13 is controlled.

In the valve closing timing control map, the relationship between the total air supply pressure (Pk + ΔP) and the valve closing timing of the air supply valve is set in advance. The valve closing timing of the air supply valve 13 is set so that the compression stroke is performed along the compression stroke (M1) line of FIG. 3, that is, the in-cylinder maximum pressure (Pmax) is set to the additional supply pressure by the electric motor 23. Therefore, the start position of the compression stroke on the line of the compression stroke (M1) is changed according to the total supply pressure (Pk + ΔP).
The closing timing of the air supply valve 13 is advanced or delayed so as to correspond to the start position.
That is, in the valve closing timing control map, the total air pressure (Pk + ΔP) and the air valve 13 are closed so that the compression stroke starts along the line of the compression stroke (M1) before the additional air pressure acts. The relationship with the valve timing is set in advance.

  Further, the supply pressure flowing into the combustion chamber 15 is directly detected by the supply pressure sensor 26, and the closing timing of the supply valve 13 is controlled by the detected value, that is, the atmospheric temperature, atmospheric pressure, humidity, etc. Since the effects of changes in outside air conditions are reflected in the supply air pressure, it is possible to accurately correct the closing timing of the supply valve in response to changes in the outside air conditions. (Pmax) can be kept constant.

For example, as shown in FIG. 4, when the outside air temperature becomes high, the supply air pressure decreases due to the decrease in air density, and the supply valve is closed when the total supply pressure (Pk + ΔP) = Pb supply stroke (M6). When the timing is set to Tb, the outside air temperature is lowered, the air density is increased, and the total supply pressure (Pk + ΔP) = Pa is the supply stroke (M7), the supply valve closing timing is set to Ta. The
Pc and Tc indicate a case where no additional pressurization by the electric motor 23 is performed.
As described above, since the optimal valve closing timing control of the air supply valve 13 is performed based on the preset total air supply pressure (Pk + ΔP), the outside air condition changes even when the additional air supply pressure acts. Even in this case, the maximum in-cylinder pressure (Pmax) is maintained at a constant and high accuracy because it proceeds on the compression stroke (M1) line before the additional supply air pressure acts.

As shown in FIG. 2, the power supply control means 93 of the control device 9 controls the signal line 31 for inputting the power generation amount of the generator 3 and the flow rate of the first flow rate adjustment valve 42 of the first bypass circuit 43. Communication line 44, a control communication line 74 for controlling the flow rate of the second flow rate adjustment valve 72 of the second bypass circuit 71, and a control line for controlling the flow rate of the third flow rate adjustment valve 51 of the third bypass circuit 52. A communication line 53, a control communication line 66 that is located downstream of the circulation pump 64 and controls the flow rate of the working medium to the evaporator 5 side of the fourth flow rate adjustment valve 65, and a load (kw) of the internal combustion engine 1 A control communication line 19 from the load sensor 28 to be detected is connected.
The power supply control means 93 adjusts each flow rate adjustment valve in accordance with the load of the internal combustion engine 1, the detected value of the supply air pressure sensor 28, and the intake air temperature sensor 27 (the supply air temperature after passing through the air cooler 25). By adjusting the heat exchange amount of the working medium in the heat exchanger, the generated power in the generator 3 is controlled.
These control the amount of power supplied to the electric motor 23 in the generator 3 so that the in-cylinder maximum pressure of the internal combustion engine 1 is less than or equal to the allowable upper limit value.
Further, the allowable intake pressure at which the in-cylinder maximum pressure of the internal combustion engine 1 is maintained below the allowable upper limit varies depending on the detected temperature (air density) of the intake temperature sensor 7.
In the present embodiment, a large number of flow rate adjustment valves are used as the control unit of the power supply control unit 93. However, an appropriate flow rate adjustment unit may be selected and controlled.

FIG. 5 shows a control flow of the power supply control means 93. Starting from step S1, the load kW signal of the internal combustion engine 1 is obtained in step S2, and the supply air pressure sensor 26 on the downstream side of the air cooler 25 in step S3. Is supplied to the control device 9.
Proceed to step S4. Step S4 is a map showing the relationship between the supply air pressure Ps and the associated maximum cylinder pressure upper limit with respect to the load kW signal. The supply air pressure Ps is a cylinder of the supply air pressure characteristic curve B with respect to the load kW. When the internal maximum pressure exceeds the supply air pressure Ps1 that is equal to or lower than the upper limit value, it is determined that the in-cylinder maximum pressure upper limit characteristic curve A exceeds the in-cylinder maximum pressure upper limit value.
On the other hand, when the supply air pressure Ps does not exceed the supply air pressure Ps1 at which the maximum in-cylinder pressure of the supply air pressure characteristic curve b is equal to or lower than the upper limit with respect to the load kW, the in-cylinder maximum pressure upper limit characteristic curve a Is determined not to exceed the maximum cylinder pressure limit.
If the supply air pressure Ps1 is not exceeded, the process proceeds to step S5, and in step S6, the current state is maintained or an increase in power supply to the hybrid turbocharger (hybrid T / C) 2 is instructed. The supply amount of the steam generated in the evaporator 5 is increased. It progresses to step S10 and returns.

  If the supply air pressure Ps1 is exceeded, the process proceeds to step S7, and an instruction is given to reduce the amount of power supplied to the hybrid supercharger 2 in step S8. That is, the steam supply amount to the steam turbine 31 of the generator 3 is decreased, and the power supply amount to the electric motor 23 of the hybrid supercharger 2 is decreased. It progresses to step S10 and returns.

  On the other hand, the flow in the case of a general diesel engine has been described, but when the valve opening / closing timing control means 91 of this embodiment is equipped, if it is determined that the supply air pressure Ps exceeds Ps1, step S7 is performed. To step S9, the air supply valve closing timing is called from the valve closing timing control map of the valve opening / closing timing control means 91, the air supply valve closing timing is called, the advance is performed, and the in-cylinder maximum pressure is set to the upper limit value Ps1. Control to: It progresses to step S10 and returns. (This will improve the efficiency of the mirror cycle engine.)

  In the present embodiment, steam is generated using the hot water of the internal combustion engine 1, the thermal energy of the exhaust gas, and the like, and the hybrid turbocharger 2 is connected to the exhaust turbine 31 by the electric power of the generator 3 including the steam turbine 31. And the electric motor 23 to improve the efficiency of the internal combustion engine 1 by controlling the supply air pressure so that the maximum in-cylinder pressure of the internal combustion engine 1 is less than the allowable value. (Improvement of output), smoke color improvement (combustion improvement) associated with an increase in air amount, mechanical strength of the internal combustion engine main body, and an effect of improving reliability against heat load.

(Second Embodiment)
In the case of gas engine (natural gas, LPG, etc.) fuel, as shown in FIG. 2, a bypass circuit 81 for bypassing the exhaust gas from the upstream side of the exhaust system of the hybrid turbocharger 2 is disposed as shown in FIG. The turbine 22 and the second heat exchanger are connected to an exhaust pipe 18, and an exhaust gas bypass valve 8 is disposed in the middle.
Since other parts are the same as described above, the description thereof is omitted.
In the case of a gas engine, the ratio of air to fuel must be maintained at a constant mixing ratio. If there is too much air relative to the fuel, the combustion speed will be slow, and if there is too much fuel relative to air, the combustion speed will be high. Abnormal combustion such as knocking may occur.
Therefore, it is necessary to quickly ensure the ratio of the air supply amount to the fuel (natural gas, LPG, etc.) against the load fluctuation.

FIG. 6 shows the flow of power supply control when gas is used as fuel, starting at step S1, detecting the load (kW) of the internal combustion engine 1 by the load sensor 28 (depending on the fuel injection amount, etc.) at step S2, In step S6, the fuel (gas) with respect to the load (kW) and the calculated calculation air amount (γs_cal) with respect to the fuel are calculated. On the other hand, the supply air pressure (Ps) detected by the supply air pressure sensor 26 in step S3 and the supply air temperature (Ts) are detected by the supply air temperature sensor 27 (see FIG. 2) in step S4. Based on the supply air pressure (Ps) in step S3 and the supply air temperature (Ts) in step S4, a measured air amount (γs_mesa) considering the air density and the like is obtained in step S7. In step S8, the amount of power supplied to the hybrid supercharger 2 (hybrid T / C) is controlled in order to adjust the measured air amount (γs_mesa) so as to be the calculated air amount (γs_cal) for the fuel (gas). The process returns at step S9.
As described above, when the fuel is a gas (natural gas, LPG, etc.), if the ratio of the fuel to the amount of air is small, the combustion speed becomes slow and the output of the internal combustion engine 1 decreases. The operation of S7 is necessary.

On the other hand, when the gas (natural gas, LPG, etc.) is used as the fuel and the valve opening / closing timing control means 91 is provided, the calculation air amount (γs_cal) is calculated in step S2 and step S6 starting from step S1. The part is the same as described above. In addition to the supply pressure (Ps) and the air density based on steps S3 and S4, in step S5, the supply valve closing timing is determined from the valve closing timing control map of the valve opening / closing timing control means 91. Is calculated. In step S7, a measured air amount (γs_mesa) in consideration of the supply air pressure (Ps), the air density, and the supply valve closing timing is obtained. In step S8, the amount of power supplied to the hybrid supercharger 2 (hybrid T / C) is controlled in order to adjust the measured air amount (γs_mesa) so as to be the calculated air amount (γs_cal) for the fuel (gas). The process returns at step S9.
In this embodiment, in addition to the effect of the first embodiment, there is an effect of cleaning exhaust gas.

  In the present embodiment, the description has been made mainly on the mirror cycle engine equipped with the valve opening / closing timing control means 91. However, as explained based on FIGS. 5 and 6, in general diesel engines, gas fuel engines, gasoline engines, and the like. Can be used as well.

  The present invention can be applied to an internal combustion engine that improves the efficiency of the internal combustion engine by increasing the supply pressure to the combustion chamber without increasing the exhaust pressure of the exhaust gas of the internal combustion engine.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Hybrid supercharger 3 Generator 4 Electric power supply apparatus 5 Evaporator 6 Working medium reproduction | regeneration apparatus 7 2nd heat exchanger 8 Exhaust gas bypass valve 9 Control apparatus 11 Cylinder 12 Piston 13 Supply valve 15 Combustion chamber 21 Compressor Part 22 Exhaust turbine 23 Electric motor 25 Intercooler 26 Supply air pressure sensor 27 Supply air temperature sensor 28 Load sensor 31 Steam turbine 41 First heat exchanger 42 First flow rate adjustment valve 43 First bypass circuit 51 Third flow rate adjustment valve 52 Third bypass circuit 61 Economizer 62 Condenser 64 Circulation pump 65 Fourth flow rate adjustment valve 72 Second flow rate adjustment valve 73 Second bypass circuit 91 Valve opening / closing timing control means 93 Electric power supply control means

Claims (8)

An exhaust turbine that is driven by exhaust gas of the internal combustion engine, an electric motor that is driven by supply of electric power, and a compressor that pressurizes supply air to the internal combustion engine by a driving force of the exhaust turbine and the electric motor. A hybrid turbocharger, a steam turbine driven by steam generated using exhaust heat of the internal combustion engine, and a generator that generates electric power by driving the steam turbine, and the electric power generated by the generator was closed and a power supply device for supplying to the hybrid turbocharger,
The power supply device further includes: an evaporator that generates the steam using exhaust heat of the exhaust gas that has passed through the exhaust turbine of the hybrid supercharger; and the hybrid supercharger and the evaporator A second heat exchanger that is provided in the exhaust system circuit and that heats the exhaust gas with steam from a boiler device provided separately from the internal combustion engine, and a second heat exchanger that is provided in parallel with the second heat exchanger. A supercharging device for an internal combustion engine , comprising: a two-bypass circuit; and a second flow rate adjusting valve provided in the second bypass circuit and having a flow rate adjusted by a control device. A pressure detection device for detecting the pressure of the supply air pressurized by the hybrid supercharger;
And a control device that controls the amount of power supplied to the hybrid supercharger so that the in-cylinder maximum pressure of the internal combustion engine becomes a permissible value or less based on the detection result of the pressure detection device. The supercharging device for an internal combustion engine according to claim 1. The power supply apparatus includes the evaporator, a condenser that condenses the steam that has driven the steam turbine, and a working medium regeneration device that includes water supply means for supplying condensed water condensed in the condenser to the evaporator. The supercharging device for an internal combustion engine according to claim 1 or 2, characterized by comprising:   The power supply device is provided on the upstream side of the evaporator, and heats the condensed water condensed by the condenser with cooling water that has cooled the internal combustion engine, and the first heat exchanger. 4. The internal combustion engine according to claim 3, further comprising: a first bypass circuit provided in parallel with the exchanger; and a first flow rate adjusting valve provided in the first bypass circuit and having a flow rate adjusted by the control device. Engine supercharger. The power supply device is provided between the evaporator and the working medium regenerator, and is provided in a third bypass circuit in which the working medium flows in parallel with the steam turbine, the third bypass circuit, and the control 5. The supercharging device for an internal combustion engine according to claim 3 , further comprising a third flow rate adjusting valve whose flow rate is adjusted by the device. The said electric power supply apparatus is interposed between the said water supply means and the said evaporator, and has a 4th flow volume adjustment valve by which the flow volume is adjusted by the said control apparatus , Any of Claim 3-5 A supercharging device for an internal combustion engine according to claim 1. The power supply device includes a fourth bypass circuit that supplies the exhaust gas discharged from the internal combustion engine to the evaporator by bypassing the exhaust turbine of the hybrid supercharger, and the fourth bypass circuit. The supercharging device for an internal combustion engine according to any one of claims 3 to 6, further comprising an exhaust gas bypass valve whose flow rate is adjusted by the control device. The internal combustion engine is a mirror cycle engine that closes an air supply valve earlier or later than bottom dead center to make the compression ratio smaller than the expansion ratio, and the air supply valve can freely change the opening and closing timing. The supercharging device for an internal combustion engine according to any one of claims 1 to 7, wherein the supercharging device is a variable air supply valve .

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