JP2011027000A - Waste heat utilization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste heat utilization device capable of drastically reducing costs of a Rankine cycle and the waste heat utilization device. <P>SOLUTION: The waste heat utilization device includes: a fluid pressure circuit (38) having a fluid pressure pump (46) for pressurizing and circulating a working fluid interposed in a circulation passage (39) of the working fluid; and the Rankine cycle (6) having an evaporator (12) for heating and evaporating a refrigerant, an expander (20) expanding the refrigerant passing through the evaporator and generating a drive force, a condenser (24) condensing the refrigerant passing through the expander, and a refrigerant pump (28) pressure-feeding the refrigerant passing through the condenser to the evaporator which are interposed sequentially in a circulation passage (7) of the refrigerant. The fluid pressure circuit is constituted by interposing a fluid pressure motor (58) driven by the fluid pressure of the fluid pressurized by the fluid pressure pump in the circulation passage of the working fluid, and the refrigerant pump is driven by the fluid pressure motor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a waste heat utilization device, and more particularly to a waste heat utilization device suitable for recovering waste heat of an internal combustion engine mounted on a vehicle.

  This type of waste heat utilization device is mounted on, for example, a vehicle, and an evaporator that heats and evaporates the refrigerant with waste heat of the internal combustion engine in the refrigerant circulation path, and expands the refrigerant that passes through the evaporator to generate driving force. It has a Rankine cycle in which an expander that is generated, a condenser that condenses the refrigerant that has passed through the expander, and a refrigerant pump that pumps the refrigerant that has passed through the condenser toward the evaporator are disposed in order. Those that recover heat are known.

And the technique of providing the bypass path which bypasses the said refrigerant | coolant pump in Rankine cycle, and controlling the refrigerant | coolant flow volume which circulates a Rankine cycle by changing the refrigerant | coolant flow volume which flows through a bypass path is disclosed (for example, patent document 1). reference).
Moreover, the technique which changes the rotation speed of the said refrigerant | coolant pump and controls the refrigerant | coolant flow volume which circulates through a Rankine cycle is disclosed (for example, refer patent document 2).

JP 59-048772 A JP-A-2005-030727

By the way, in each said prior art, the rotation source of a refrigerant | coolant pump is not explained in full detail, but in the said patent document 1, it is thought that the constant-speed electric motor which rotates a refrigerant | coolant pump at a fixed speed is used for the said rotation source. On the other hand, in Patent Document 2, it is considered that a variable electric motor that rotates the refrigerant pump at a variable speed is used as the rotation source.
However, when a variable electric motor is used as the rotation source of the refrigerant pump, an expensive inverter motor is generally used, and there is a problem that the cost of the Rankine cycle and thus the waste heat utilization device increases.

  This invention is made | formed in view of such a subject, and it aims at providing the waste heat utilization apparatus which can reduce significantly the Rankine cycle and by extension, the cost of a waste heat utilization apparatus.

  In order to achieve the above object, a waste heat utilization apparatus according to claim 1 includes a fluid pressure circuit in which a working fluid circulation circuit is interposed in a working fluid circulation path to pressurize and circulate the working fluid, and a refrigerant circulation path. An evaporator that heats and evaporates the refrigerant, an expander that expands the refrigerant that passes through the evaporator to generate driving force, a condenser that condenses the refrigerant that passes through the expander, and an evaporator that passes through the condenser And a Rankine cycle in which refrigerant pumps that are pumped toward the fluid are sequentially inserted, and the fluid pressure circuit includes a fluid pressure motor driven by the fluid pressure of the fluid pressurized by the fluid pressure pump in the working fluid circulation path. The refrigerant pump is inserted and is driven by a fluid pressure motor.

According to a second aspect of the present invention, in the first aspect, the evaporator heats and evaporates the refrigerant by the waste heat of the internal combustion engine that drives the vehicle, and the fluid pressure circuit is operated by being pressurized by the fluid pressure pump. A vehicle mechanism for assisting driving of the vehicle is driven by fluid pressure of the fluid.
Furthermore, the invention of claim 3 is characterized in that, in claim 2, the fluid pressure motor is connected in parallel to the vehicle mechanism in the fluid pressure circuit.

Furthermore, the invention of claim 4 is characterized in that in any one of claims 1 to 3, a control means is provided for controlling the inflow amount of the working fluid to the fluid pressure motor in accordance with the operation control status of the Rankine cycle. It is said.
According to a fifth aspect of the present invention, in the fourth aspect, the fluid pressure circuit has pressure detection means for detecting the fluid pressure of the working fluid pressurized by the fluid pressure pump, and the control means is provided in the pressure detection means. When the detected fluid pressure is equal to or lower than a predetermined first lower limit pressure, the inflow of the working fluid to the fluid pressure motor is limited.

Furthermore, in the invention of claim 6, in claim 5, the fluid pressure circuit is characterized in that an accumulator is inserted in a working fluid circulation path between the fluid pressure pump and the vehicle mechanism.
Furthermore, the invention of claim 7 is characterized in that, in claim 6, the fluid pressure pump is driven by the driving force of the internal combustion engine.

According to an eighth aspect of the present invention, in the sixth aspect, the Rankine cycle has a generator motor connected coaxially to the expander, and the fluid pressure pump is a driving force of the expander and / or the generator motor. It is characterized by being driven by.
Further, in the ninth aspect of the present invention, in the eighth aspect, when the fluid pressure detected by the pressure detecting means is equal to or lower than a predetermined second lower limit pressure, the control means causes the fluid pressure pump to be driven by the driving force of the generator motor. It is characterized by driving.

Furthermore, in the invention of claim 10, in claim 8, the control means sets the fluid pressure pump to an expander and / or generator motor so that the fluid pressure detected by the pressure detection means becomes a predetermined set pressure. It is characterized by being driven by the driving force of
In the invention of claim 11, the Rankine cycle according to claim 8 is characterized in that an expander, a generator motor, and a fluid pressure pump are coaxially connected.

Furthermore, the invention of claim 12 is characterized in that, in any of claims 7 to 11, the fluid pressure pump is a hydraulic pump and the vehicle mechanism is a power steering mechanism of the vehicle.
Furthermore, the invention of claim 13 is characterized in that, in any of claims 7 to 11, the fluid pressure pump is a hydraulic pump and the vehicle mechanism is an active suspension mechanism of the vehicle.

  According to the waste heat utilization apparatus of the first aspect of the present invention, in the fluid pressure circuit, the fluid pressure motor driven by the fluid pressure of the fluid pressurized by the fluid pressure pump is inserted in the working fluid circulation path. Thus, the refrigerant pump is driven by a fluid pressure motor. This makes it possible to secure a rotation source capable of changing the number of revolutions of the refrigerant pump without using a generally expensive inverter motor for the refrigerant pump, thereby greatly reducing the cost of the Rankine cycle and thus the waste heat utilization device. can do.

Further, according to the invention of claim 2, specifically, the evaporator heats and evaporates the refrigerant by waste heat of the internal combustion engine that drives the vehicle, and the fluid pressure circuit is pressurized by the fluid pressure pump. The vehicle mechanism that assists in driving the vehicle is driven by the fluid pressure of the working fluid.
According to a third aspect of the present invention, the fluid pressure motor is connected in parallel to the vehicle mechanism in the fluid pressure circuit, so that the fluid pressure motor is more fluid than the case where the fluid pressure motor is connected in series to the vehicle mechanism. The influence on the driving of the vehicle mechanism can be reduced by controlling the pressure motor.

  Furthermore, according to the invention of claim 4, the control means for controlling the inflow amount of the working fluid to the fluid pressure motor according to the operation control status of the Rankine cycle is provided. Here, the amount of heat radiation that can be radiated by the condenser is determined in accordance with the outside air temperature and the vehicle speed, and it is preferable that the evaporator recovers waste heat having an appropriate amount of heat corresponding to the amount of heat radiation. The reason is that if the number of revolutions of the refrigerant pump increases, the amount of waste heat recovered in the evaporator is too large to dissipate heat in the condenser, and the low-pressure side pressure (condensation pressure) of the refrigerant in the Rankine cycle increases and expands. Since the differential pressure of the refrigerant before and after the machine is lowered, the output of the Rankine cycle is lowered. On the other hand, if the rotational speed of the refrigerant pump is too small, the amount of waste heat recovered in the evaporator is reduced, the flow rate of refrigerant circulating in the circulation path is reduced, and the Rankine cycle output is reduced. Therefore, the amount of waste heat recovered in the evaporator, that is, the Rankine cycle, is changed to the amount of heat released by the condenser by controlling the rotation speed of the fluid pressure motor and eventually the refrigerant pump according to the operation control status of the Rankine cycle. The amount of heat can be adjusted appropriately. Therefore, the output of the Rankine cycle can be reliably prevented by appropriately varying the rotational speed of the refrigerant pump in conjunction with the drive of the fluid pressure circuit such as the vehicle mechanism.

  According to the invention of claim 5, the control means limits the inflow of the working fluid to the fluid pressure motor when the fluid pressure detected by the pressure detection means is equal to or lower than a predetermined first lower limit pressure. Thus, when the fluid pressure of the working fluid decreases during idling or deceleration of the vehicle, the vehicle mechanism can be preferentially driven over the fluid pressure motor by the fluid pressure of the working fluid. It is possible to prevent troubles in driving the vehicle.

  According to a sixth aspect of the present invention, the fluid pressure circuit is configured such that an accumulator is interposed in the working fluid circulation path between the fluid pressure pump and the vehicle mechanism. Thereby, the surplus fluid pressure of the working fluid is accumulated, and the vehicle mechanism or the fluid pressure motor can be driven by the accumulated fluid pressure, thereby preventing the vehicle from being hindered by the Rankine cycle, The Rankine cycle, and thus the waste heat recovery efficiency of the waste heat utilization device can be improved.

Furthermore, according to the invention of Claims 7 and 8, the fluid pressure pump is driven by the driving force of the internal combustion engine (Claim 7) or the Rankine cycle expander and / or the generator motor (Claim 8). .
In particular, according to the invention of claim 8, by driving the fluid pressure pump, the fluid pressure motor, and eventually the refrigerant pump with the energy generated in the Rankine cycle, the driving energy between the Rankine cycle and the vehicle mechanism is obtained. The balance can be completed. Therefore, all of the driving force of the internal combustion engine can be effectively utilized for driving the vehicle.

  Moreover, since the drive of the fluid pressure pump can be assisted by the expander or the generator motor, in particular, the driving force required to drive the vehicle mechanism is increased, while the fluid pressure required for the fluid pressure circuit is increased. Since the vehicle mechanism can be driven preferentially over the fluid pressure motor when the vehicle is idling or decelerating because the waste heat collected in the Rankine cycle is low, the Rankine cycle hinders the vehicle drive. This can be surely prevented.

  According to the invention of claim 9, the control means drives the fluid pressure pump by the driving force of the generator motor when the fluid pressure detected by the pressure detection means is equal to or lower than a predetermined second lower limit pressure. As a result, even if the output of the expander decreases when the vehicle is idling, etc., the fluid pressure pump can be driven by the power stored in the generator motor. It can prevent reliably, and it can prevent much more reliably that it interferes with the drive of a vehicle by Rankine cycle.

Further, according to the invention of claim 10, the control means sets the fluid pressure pump by the driving force of the expander and / or the generator motor so that the fluid pressure detected by the pressure detection means becomes a predetermined set pressure. To drive. Thereby, since the working fluid pressure of the fluid pressure circuit can be made constant by the expander and / or the generator motor, the vehicle drive can be stabilized.
Furthermore, according to the invention of claim 11, the Rankine cycle is formed by coaxially connecting an expander, a generator motor, and a fluid pressure pump. Thereby, space saving in Rankine cycle and reduction of components can be achieved, and the cost of the Rankine cycle and thus the waste heat utilization device can be further reduced.

  Further, according to the inventions of claims 12 and 13, specifically, the fluid pressure pump is a hydraulic pump, and the vehicle mechanism is a vehicle power steering mechanism (claim 12) or an active suspension mechanism (claim 13). It is.

It is the schematic diagram which showed the waste-heat utilization apparatus of the internal combustion engine which concerns on 1st Embodiment of this invention. 2 is a flowchart showing a control routine of hydraulic motor control according to a waste heat recovery amount executed by an ECU of FIG. 1. 3 is a flowchart showing a control routine for hydraulic motor control according to hydraulic pressure executed by the ECU of FIG. 1. It is the schematic diagram which showed the waste-heat utilization apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described first from the first embodiment with reference to the drawings.
FIG. 1 schematically shows an example of a waste heat utilization device for an internal combustion engine. The waste heat utilization device 1 is mounted on a vehicle and a cooling water circuit 4 that cools an engine (internal combustion engine) 2 of the vehicle, A Rankine cycle 6 (hereinafter referred to as an RC circuit) that recovers waste heat of the engine 2 is provided.
The cooling water circuit 4 is connected to a cooling water circulation path 5 extending from the engine 2 in order from the flow direction of the cooling water in order of the exhaust gas heat exchanger 8, a superheater 10 described later, an evaporator 12 described later, a radiator 14, and a thermostat. 16, the water pump 18 is inserted and the closed circuit is comprised.

The exhaust gas heat exchanger 8 exchanges heat between the cooling water heated by cooling the cylinder block 3 of the engine 2 and the exhaust gas discharged from the exhaust gas pipe 9 of the engine 2 via the engine 2 at a predetermined set temperature. Further heating until.
The radiator 14 is arranged in series with the evaporator 12, and further cools the cooling water that has been absorbed by the refrigerant in the evaporator 12 and is cooled by heat exchange with the outside air or the like.

  The thermostat 16 is a mechanical three-way valve that controls the amount of cooling water passed to the radiator 14 in accordance with the temperature of the cooling water flowing into the thermostat 16, and includes two inlet ports and one outlet port. Have. A flow path 5a extending from the radiator 14 and a radiator bypass path 5c connected to bypass the radiator 14 from the flow path 5b between the evaporator 12 and the radiator 14 are connected to the two inlet ports, respectively. Thus, the amount of cooling water passed to the radiator 12 is increased or decreased according to the cooling water temperature, so that the cooling water temperature, and thus the temperature of the cylinder block 3 is properly maintained.

The water pump 18 is attached to the engine 2 and is driven according to the rotational speed of the engine 2 to circulate the cooling water suitably in the cooling water circuit 4.
On the other hand, the RC circuit 6 is connected to a circulation path 7 of a refrigerant such as Freon R134a as a working fluid in order from the flow direction of the refrigerant, the evaporator 12, the superheater 10, the expander 20, the regenerator 22, the condenser 24, A gas-liquid separator 26 and a refrigerant pump 28 are inserted to form a closed circuit.

The evaporator 12 causes the refrigerant pumped by the refrigerant pump 28 to exchange heat with cooling water that has passed through the engine 2, the exhaust gas heat exchanger 8, and the superheater 10 in order to evaporate at a predetermined evaporation temperature.
The superheater 10 exchanges heat between the refrigerant that has passed through the evaporator 12 and the cooling water that has passed through the exhaust gas heat exchanger 8 to make it superheat.
The expander 20 is a rotating device that generates a rotational driving force by expanding the refrigerant that has been brought into a superheated state via the superheater 10. The expander 20 receives the driving force generated by the expander 20. A generator 30 that is converted into electric power and can be used outside the waste heat utilization apparatus 1 is mechanically connected coaxially.

The regenerator 22 is a heat exchanger that heats the refrigerant before flowing into the evaporator 12 via the refrigerant pump 28 by the refrigerant before flowing into the condenser 24 via the expander 20.
The condenser 24 is a radiator that condenses and liquefies the refrigerant that has passed through the regenerator 22 by heat exchange with the outside air by blowing air from the fan 25.
The gas-liquid separator 26 separates the refrigerant condensed in the condenser 24 into gas-liquid two layers, and only the liquid refrigerant separated here flows out to the refrigerant pump 28.

The refrigerant pump 28 pumps the liquid refrigerant separated by the gas-liquid separator 26 toward the evaporator 12 and circulates it appropriately in the RC circuit 6.
The coolant circuit 4 and the RC circuit 6 configured as described above are controlled by an ECU 32 that is an electronic control device that comprehensively controls the vehicle.
By the way, in this embodiment, the vehicle is a power steering mechanism (vehicle mechanism) 36 (hereinafter referred to as a power steering mechanism) as an auxiliary mechanism for turning the steering 34 for steering the vehicle, and a working fluid for driving the power steering mechanism 36. And a hydraulic circuit (fluid pressure circuit) 38 through which the oil circulates.

The power steering mechanism 36 includes wheels 40 that are steered by the steering 34, a power cylinder 42, and a control valve 44, so that the driver of the vehicle can turn the steering 34 lightly without any sense of incongruity.
Specifically, the high pressure side and the low pressure side of the hydraulic circuit 38 are maintained at a predetermined pressure difference, and the steering 34 is controlled by the amount of oil flowing into the power cylinder 42. For example, the hydraulic circuit 38 causes a large amount of oil to flow through the power cylinder 42 when the driver of the vehicle turns the steering 34 large, while the power cylinder 42 when the driver turns the steering 34 small. The hydraulic circuit 38 always requires a predetermined amount of oil.

The power cylinder 42 adjusts the hydraulic pressure as necessary by a hydraulic circuit 38 so that the steering 34 is light when the vehicle is running at low speed or when the engine 2 is idling, and the steering 34 is rotated slightly heavier when the vehicle is running at high speed. An appropriate amount of oil is supplied.
The control valve 44 controls the operation direction of the power cylinder 42 by switching the direction of the hydraulic pressure applied to the power cylinder 42 according to the direction in which the steering 34 is rotated.

On the other hand, the hydraulic circuit 38 forms a closed circuit by inserting a hydraulic pump (fluid pressure pump) 46, a tank (accumulator) 48, and a control valve 44 in order from the oil flow direction into the oil circulation path 39. Yes.
The hydraulic pump 46 is a so-called vane pump, gear pump, or piston pump, pressurizes oil to circulate it in the circulation path 39 and generates hydraulic pressure for driving the power steering mechanism 36. The driving force of the engine 2 is transmitted to the rotating shaft of the hydraulic pump 46 via the pulley 50 and the belt 52, and the hydraulic pump 46 is driven by the driving force of the engine 2.

The tank 48 is a so-called accumulator capable of accumulating excess pressure of high-pressure oil pressurized by the hydraulic pump 46 and driving the power steering mechanism 36 by the accumulated oil pressure.
The hydraulic circuit 38 includes a bypass passage 54 that bypasses the hydraulic pump 46, and a pressure regulating valve 56 is inserted in the bypass passage 54.

The pressure regulating valve 56 is connected to a driving unit that drives the valve body by a pressure guiding pipe 57 extending from a circulation path 39 between the hydraulic pump 46 and the tank 48, and is hydraulic pressure guided from the pressure guiding pipe 57. This is a mechanism valve that opens and closes in response to the oil pressure, and the oil sent from the hydraulic pump 46 is returned to the low pressure side of the hydraulic circuit 38 to prevent the oil on the high pressure side of the hydraulic circuit 38 from becoming excessively high pressure. .
The hydraulic circuit 38 configured as described above flows into the power cylinder 42 by using the hydraulic pressure accumulated in the tank 48 in addition to pressurization by the hydraulic pump 46 during low-speed driving or idling of the vehicle. By increasing the amount of oil, the high pressure side and the low pressure side of the hydraulic circuit 38 are maintained at a predetermined pressure difference, and the steering 34 can be operated lightly. On the other hand, at the time of high-speed driving of the vehicle, the minimum amount of oil necessary for driving the power steering mechanism 36 is supplied to the power cylinder 42, thereby increasing the operation of the steering 34. Further, when the hydraulic pump 46 is driven in a higher rotational speed than necessary due to the high rotation of the engine 2 during normal operation of the vehicle, the oil flows into the bypass passage 54, and thereby the low pressure side of the hydraulic circuit 38. And a predetermined pressure difference between the high pressure side is maintained.

  Here, in the hydraulic circuit 38 of the present embodiment, a parallel path 39 a of the circulation path 39 is provided in parallel with the control valve 44, and the parallel path 39 a is driven by the hydraulic pressure of oil pressurized by the hydraulic pump 46. A hydraulic motor (fluid pressure motor) 58 is inserted, in other words, the hydraulic motor 58 is connected in parallel to the power steering mechanism 36 in the hydraulic circuit 38, and the refrigerant pump 28 is driven by the hydraulic motor 58.

The hydraulic motor 58 is a rotating device that generates a rotational driving force by the hydraulic pressure generated by the hydraulic pump 46, and controls the rotational speed of the rotary shaft 59 of the hydraulic motor 58 by controlling the amount of oil flowing into the hydraulic motor 58. can do. The rotating shaft 59 is coaxial with the refrigerant pump 28, and the hydraulic motor 58 is used as a rotation source of the refrigerant pump 28.
Further, a flow rate adjusting valve 60 for controlling the amount of oil flowing into the hydraulic motor 58 is inserted in the parallel path 39a.

The flow rate adjustment valve 60 is an electric on-off valve, and its drive unit is electrically connected to the ECU 32.
Further, a pressure sensor (pressure detection means) 62 which is also electrically connected to the ECU 32 is connected between the connection position 39 b of the bypass path 54 on the downstream side of the hydraulic pump 46 in the circulation path 39 and the connection position 39 c of the pressure guiding pipe 57. Is provided.

  Here, the amount of heat dissipated by the condenser 24 is affected by disturbance factors for the RC circuit 6 such as the outside air temperature and the vehicle speed, and the evaporator 12 generates waste heat having an appropriate amount of heat corresponding to the amount of heat dissipated. It is preferable to recover. This is because when the rotational speed of the refrigerant pump 28 is increased, the amount of waste heat recovered in the evaporator 12 is too large to dissipate heat in the condenser 24, and the low-pressure side pressure (condensation pressure) of the refrigerant in the RC circuit 6 is increased. When the pressure difference between the refrigerant before and after the expander 20 rises and the rotation speed of the refrigerant pump 28 is too small, the amount of waste heat recovered in the evaporator 12 decreases and the refrigerant flow rate circulating in the circulation path 7 This is because the rotational speed of the expander 20 is reduced, that is, the output of the RC circuit 6 is reduced.

  Therefore, the ECU 32 calculates an actual waste heat recovery amount Q in the RC circuit 6 based on signals from an outside air temperature sensor and a vehicle speed sensor (not shown) input to the ECU 32, and a target waste heat recovery corresponding to the heat dissipation amount. Set the quantity Qs. The ECU 32 controls the operation of the RC circuit 6 to increase the output of the RC circuit 6 so that the waste heat recovery amount Q follows the target waste heat recovery amount Qs. Further, the ECU 32 controls the rotational speed of the hydraulic motor 58 by controlling the amount of oil flowing into the hydraulic motor 58 by opening and closing the flow rate adjustment valve 60 according to the operation control status of the RC circuit 6. As a result, the rotational speed of the refrigerant pump 28 is controlled, and hydraulic motor control for appropriately adjusting the waste heat recovery amount Q to the target waste heat recovery amount Qs is executed (control means).

Hereinafter, a control routine for hydraulic motor control according to the amount of recovered waste heat executed in the ECU 32 will be described with reference to the flowchart of FIG.
First, when this control is started, the process proceeds to S1 (S represents a step, and the same shall apply hereinafter). In S1, the waste heat recovery amount Q recovered in the RC circuit 6 is equal to or greater than the target waste heat recovery amount Qs. It is determined whether or not (Q ≧ Qs). When it is determined that the determination result is true (Yes) and Q ≧ Qs is established, the process proceeds to S2, and when the determination result is false (No), Q ≧ Qs If it is determined that is not established, the process proceeds to S3.

In S2, the flow regulating valve 60 that is opened is closed, or when the flow regulating valve 60 is already closed, the flow regulating valve 60 is kept closed to restrict the inflow of oil to the hydraulic motor 58. Return this control routine.
On the other hand, in S3, the closed flow rate adjustment valve 60 is opened, the restriction on the amount of oil flowing into the hydraulic motor 58 is released, or when the flow rate adjustment valve 60 is already opened, the valve is opened. In this state, the oil is actively flowed into the hydraulic motor 58, and this control routine is returned.

Further, in the hydraulic motor control, the flow rate adjustment valve 60 is opened and closed according to the hydraulic pressure on the high pressure side of the hydraulic circuit 38 detected by the pressure sensor 62, and judgment information for controlling the flow rate adjustment valve 60 includes: The hydraulic pressure on the high pressure side of the hydraulic circuit 38 has priority over the operation control status of the RC circuit 6 (control means).
Hereinafter, a control routine for hydraulic motor control corresponding to the hydraulic pressure executed in the ECU 32 will be described with reference to the flowchart of FIG.

First, when this control is started, the process proceeds to S11. In S11, is the hydraulic pressure P detected by the pressure sensor 62 equal to or lower than a predetermined lower limit pressure (first lower limit pressure) P _L1 (P ≦ P _L1 )? If the determination result is true (Yes) and it is determined that P ≦ P _L1 is satisfied, the process proceeds to S12, and the determination result is false (No) and it is determined that P ≦ P _L1 is not satisfied. If yes, the process proceeds to S13. The lower limit pressure P _L1 is set to a minimum required hydraulic pressure for driving the power steering mechanism 36 at the time of low speed operation or idling of the vehicle.

In S12, the flow rate adjustment valve 60 that is opened is closed, or when the flow rate adjustment valve 60 is already closed, the flow rate adjustment valve 60 is kept closed to restrict the inflow of oil to the hydraulic motor 58. Return this control routine.
On the other hand, in S13, the closed flow rate adjustment valve 60 is opened, the restriction on the amount of oil flowing into the hydraulic motor 58 is released, or when the flow rate adjustment valve 60 is already opened, the valve is opened. In this state, the oil is actively flowed into the hydraulic motor 58, and this control routine is returned.

  As described above, in this embodiment, the hydraulic circuit 38 is provided with the hydraulic motor 58 driven by the hydraulic pressure of the oil pressurized by the hydraulic pump 46, and the refrigerant pump 28 is driven by the hydraulic motor 58. Since a rotation source capable of changing the rotation speed of the refrigerant pump 28 can be secured without using an expensive inverter motor for the refrigerant pump 28 in general, the cost of the RC circuit 6 and consequently the waste heat utilization apparatus 1 is greatly increased. Can be reduced.

Further, by executing the above hydraulic motor control, the rotational speed of the hydraulic motor 58 and thus the refrigerant pump 28 can be controlled according to the amount of waste heat recovered and the hydraulic pressure in the RC circuit. Thus, the rotational speed of the refrigerant pump 28 can be varied appropriately.
Specifically, the amount of waste heat recovered by the RC circuit 6 is released by the condenser by controlling the rotational speed of the hydraulic motor 58 and the refrigerant pump 28 in accordance with the operation control status of the RC circuit 6. Since the amount of heat can be appropriately adjusted to the amount of heat, the output of the RC circuit 6 can be reliably prevented by appropriately varying the number of revolutions of the refrigerant pump 28 in conjunction with the drive of the power steering mechanism 36. Can do.

Further, when the oil pressure P detected by the pressure sensor 62 is below the lower limit pressure P _L1, by limiting the flow of oil to the hydraulic motor 58, when the oil pressure is lowered during the idling or deceleration of the vehicle, the hydraulic Thus, the power steering mechanism 36 can be driven preferentially over the hydraulic motor 58, so that it is possible to prevent the vehicle from being hindered by the operation control of the RC circuit 6.

Further, since the hydraulic circuit 38 is provided with the tank 48, the excess hydraulic pressure on the high pressure side of the hydraulic circuit 38 can be accumulated, and the hydraulic motor 58 and thus the refrigerant pump 28 can be driven by the accumulated hydraulic pressure. Thus, it is possible to improve the waste heat recovery efficiency of the RC circuit 6 and thus the waste heat utilization apparatus 1 while preventing the vehicle from being hindered.
Further, the hydraulic motor 58 is connected in parallel to the power steering mechanism 36 in the hydraulic circuit 38, so that the power steering mechanism 36 is controlled by controlling the hydraulic motor 58 as compared with the case where the hydraulic motor 58 is connected in series to the power steering mechanism 36. The influence on driving can be reduced.

Next, a second embodiment of the present invention will be described.
FIG. 4 schematically shows a schematic diagram of the internal combustion engine waste heat utilization apparatus of the second embodiment.
In the second embodiment, the rotation source of the hydraulic pump 46 in the first embodiment is replaced with the expander 20 and / or the generator motor 31 from the engine 2, and the other configurations are the same as those in the first embodiment. I am doing.

The expander 20 and the pulley 64 are connected to the rotating shaft of the generator motor 31, and the expander 20 and / or the generator motor 31 are driven to the rotating shaft of the hydraulic pump 46 via the pulleys 50, 64 and the belt 52. Power is transmitted.
The generator motor 31 functions as a generator by the rotation of the expander 20, and electricity generated by the generator is stored in a battery (not shown). In a predetermined case, the generator motor is driven by electricity stored in the battery. Thus, the hydraulic pump 46 is driven by the driving force of the generator motor 31.

Further, when the power of the expander 20 is insufficient, such as when the vehicle is idling, the hydraulic pressure P detected by the pressure sensor 62 in the ECU 32 is equal to or lower than a predetermined lower limit pressure (second lower limit pressure) P _L2 (P ≦ When P _L2 ), the hydraulic pump 58 is driven by the driving force of the generator motor 31 (control means).
As described above, in the present embodiment, since the rotation source of the refrigerant pump 28 can be secured without using an inverter motor, as in the first embodiment, the RC circuit 6 and eventually the waste heat utilization device 1 can be secured. Cost can be greatly reduced.

Particularly in the second embodiment, the energy generated in the RC circuit 6 is used to drive the hydraulic pump 46, the hydraulic motor 58, and the refrigerant pump 28, thereby driving these between the RC circuit 6 and the power steering mechanism 36. Energy balance can be completed. Therefore, all of the driving force of the engine 2 can be effectively used for driving the vehicle.
Moreover, since the driving of the hydraulic pump 46 can be assisted by the generator motor 31, the driving force required for driving the power steering mechanism 36 is increased, and the hydraulic pressure required for the hydraulic circuit 38 is increased, while the RC circuit The power steering mechanism 36 can be driven more preferentially than the hydraulic motor 58 when the vehicle is idling or decelerating that the waste heat recovered at 6 is low, so that the RC circuit 6 hinders driving of the vehicle. Can be surely prevented.

Furthermore, even when the output of the expander 20 is small when the vehicle is idling or decelerating, the hydraulic motor 58 can be driven by the accumulated power of the generator motor 31 to prevent the hydraulic pressure of the hydraulic circuit 38 from being lowered. The RC circuit 6 can more reliably prevent the vehicle from being hindered.
Although the description of one embodiment of the present invention has been completed above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in each of the embodiments described above, the flow rate adjustment valve 60 that controls the amount of oil flowing into the hydraulic motor 58 is used. However, the present invention is not limited to this, and a bypass path that bypasses the hydraulic motor 58 is provided. A bypass valve may be provided to control this.
In each of the above embodiments, the driving force is transmitted to the hydraulic pump 46 via the pulleys 50 and 64 and the belt 52. However, the configuration is not limited to this, and the hydraulic pump 46 is configured coaxially with the engine 2 and the generator motor 31. Alternatively, the hydraulic pump 46 may be an electric pump as long as the rotational speed is controlled so as to obtain the functions and effects of the above embodiments.

Here, in the case of either a rotating source of the hydraulic pump 46 of the expander 20 or the generator motor 31 also, as the hydraulic pressure P detected by the pressure sensor 62 reaches a predetermined set pressure P _S, the hydraulic pump 46 is preferably driven by the driving force of the expander 20 and / or the generator motor 31 (control means). In this case, since the hydraulic pressure of the hydraulic circuit 38 can be kept constant by the expander 20 and / or the generator motor 31, the vehicle drive can be stabilized.

Further, in order to realize the above-described control, the RC circuit 6 is configured by connecting the expander 20, the generator motor 31, and the hydraulic pump 46 coaxially, thereby reducing the space in the RC circuit 6 and the configuration. The number of parts can be reduced, and the cost of the RC circuit 6 and the waste heat utilization apparatus 1 can be further reduced.
Furthermore, in each of the above-described embodiments, the hydraulic circuit 38 of the power steering mechanism 36 is linked to the RC circuit 6, but this is not a limitation, and the hydraulic circuit (active suspension mechanism (vehicle mechanism)) of the vehicle (not shown) is not shown. A fluid pressure circuit), a pneumatic circuit (fluid pressure circuit) of a vehicle air brake mechanism (vehicle mechanism), and the like may be linked to the RC circuit 6.

  Moreover, you may link the hydraulic circuit of the apparatus used for not only each said vehicle mechanism but various fields, such as plant equipment, with RC circuit. Specifically, it is conceivable to link a hydraulic circuit provided in the gas turbine / boiler power generator with an RC circuit that recovers waste heat of the gas turbine / boiler power generator. The hydraulic circuit of this device includes, for example, lubrication of the rotating shaft of the gas turbine, a drive source of a control valve that controls the fuel flow rate of fuel supplied to the device, and a control that controls the flow rate of steam and gas sent to the gas turbine. What is used as a drive source of a valve is known.

1 Waste heat utilization device 2 Engine (internal combustion engine)
6 Rankine cycle 7 Circuit (refrigerant circuit)
DESCRIPTION OF SYMBOLS 12 Evaporator 20 Expander 24 Condenser 28 Refrigerant pump 30 Generator 31 Generator motor 36 Power steering mechanism (vehicle mechanism, active suspension mechanism)
38 Hydraulic circuit (fluid pressure circuit)
39 Circuit (working fluid circuit)
46 Hydraulic pump (hydraulic pressure pump)
48 tanks (accumulator)
58 Hydraulic motor
62 Pressure sensor (pressure detection means)

Claims (13)

A fluid pressure circuit having a fluid pressure pump interposed in the working fluid circulation path to pressurize and circulate the working fluid;
An evaporator that heats and evaporates the refrigerant in a circulation path of the refrigerant; an expander that expands the refrigerant that passes through the evaporator to generate a driving force; a condenser that condenses the refrigerant that passes through the expander; A Rankine cycle sequentially inserted with a refrigerant pump that pumps the refrigerant through the condenser toward the evaporator,
The fluid pressure circuit is configured such that a fluid pressure motor driven by a fluid pressure of a fluid pressurized by the fluid pressure pump is inserted in the circulation path of the working fluid.
The waste heat utilization apparatus, wherein the refrigerant pump is driven by the fluid pressure motor. The evaporator heats and evaporates the refrigerant by waste heat of an internal combustion engine that drives a vehicle,
2. The waste heat utilization apparatus according to claim 1, wherein the fluid pressure circuit drives a vehicle mechanism that assists driving of the vehicle by a fluid pressure of a working fluid pressurized by the fluid pressure pump.   The waste heat utilization apparatus according to claim 2, wherein the fluid pressure motor is connected in parallel to the vehicle mechanism in the fluid pressure circuit.   The waste heat utilization apparatus according to any one of claims 1 to 3, further comprising a control unit that controls an inflow amount of the working fluid to the fluid pressure motor according to an operation control state of the Rankine cycle. The fluid pressure circuit has pressure detection means for detecting the fluid pressure of the working fluid pressurized by the fluid pressure pump,
5. The waste of claim 4, wherein the control means limits the inflow of the working fluid to the fluid pressure motor when the fluid pressure detected by the pressure detection means is equal to or lower than a predetermined first lower limit pressure. Heat utilization device.   6. The waste heat utilization apparatus according to claim 5, wherein the fluid pressure circuit has an accumulator interposed in the circulation path of the working fluid between the fluid pressure pump and the vehicle mechanism.   The waste heat utilization apparatus according to claim 6, wherein the fluid pressure pump is driven by a driving force of the internal combustion engine. The Rankine cycle has a generator motor connected coaxially to the expander,
The waste heat utilization apparatus according to claim 6, wherein the fluid pressure pump is driven by a driving force of the expander and / or the generator motor.   The said control means drives the said fluid pressure pump with the drive force of the said generator motor, when the fluid pressure detected by the said pressure detection means is below a predetermined 2nd minimum pressure. Waste heat utilization equipment.   The control means drives the fluid pressure pump by a driving force of the expander and / or the generator motor so that the fluid pressure detected by the pressure detection means becomes a predetermined set pressure. The waste heat utilization apparatus according to claim 8.   The waste heat utilization apparatus according to claim 8, wherein the Rankine cycle is configured such that the expander, the generator motor, and the fluid pressure pump are coaxially connected.   12. The waste heat utilization apparatus according to claim 7, wherein the fluid pressure pump is a hydraulic pump, and the vehicle mechanism is a power steering mechanism of the vehicle.   The waste heat utilization apparatus according to any one of claims 7 to 11, wherein the fluid pressure pump is a hydraulic pump, and the vehicle mechanism is an active suspension mechanism of the vehicle.

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