WO2013046936A1

WO2013046936A1 - Device for using engine waste heat

Info

Publication number: WO2013046936A1
Application number: PCT/JP2012/070043
Authority: WO
Inventors: 永井　宏幸; 貴幸石川; 真一朗溝口; 今井　智規
Original assignee: 日産自動車株式会社; サンデン株式会社
Priority date: 2011-09-30
Filing date: 2012-08-07
Publication date: 2013-04-04
Also published as: JP2013076514A

Abstract

This device for using engine waste heat, which is provided with a Rankine cycle containing a coolant pump that is driven by motive force regenerated by an expander, is provided with: a refrigeration cycle that shares a condenser, and that includes an evaporator that guides and evaporates the coolant from the condenser; an ejector that uses the coolant at the exit of a heat exchanger as driver gas to draw in the coolant from the exit of the evaporator and return the coolant to the condenser; and a flow rate distribution ratio control mechanism that can control the distribution ratio of the coolant flow rate supplied from the exit of the heat exchanger to the ejector and the coolant flow rate supplied from the exit of the heat exchanger to the expander.

Description

Waste heat utilization device of engine

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a waste heat utilization device for an engine, and more particularly to an integrated one with a Rankine cycle and a refrigeration cycle.

There is known a technique for performing a Rankine cycle operation and a refrigeration cycle operation by driving an ejector (see JP2004-322933A).

However, JP2004-322933A does not disclose that the refrigerant serving as the drive source of the ejector is supplied using engine waste heat. Therefore, there is no description about distributing the refrigerant supplied by the refrigerant pump driven by the expander torque to the expander and the ejector under such a premise configuration.

Efficiency is improved by changing the ratio of the refrigerant supplied to the expander driving the refrigerant pump and the refrigerant supplied to the ejector according to the environment (conditions) in which the waste heat utilization device is placed. For example, under conditions where the capacity of the condenser is high (the amount of heat release is large), high expander torque can be obtained even with a relatively small amount of refrigerant, so by relatively increasing the amount of refrigerant supplied to the ejector, the output of the refrigeration cycle (cooling Ability) can be improved.

The present invention can arbitrarily adjust the driving force (the amount of refrigerant) of the refrigerant pump and the driving force (the amount of refrigerant) of the ejector when circulating the refrigerant that is also the driving source of the ejector using engine waste heat. It is an object of the present invention to provide a waste heat utilization apparatus with further improved efficiency by configuring the

The present invention comprises a heat exchanger for recovering engine waste heat into a refrigerant, an expander for generating power using the refrigerant at the outlet of the heat exchanger, a condenser for condensing the refrigerant leaving the expander, and the expander The present invention is directed to a waste heat utilization device of an engine provided with a Rankine cycle that includes a refrigerant pump that is driven by the power regenerated by the engine and that supplies the refrigerant from the condenser to the heat exchanger. And, in the waste heat utilization device of the engine of the present invention, the refrigeration cycle including the evaporator sharing the condenser and guiding and evaporating the refrigerant from the condenser, and using the refrigerant at the heat exchanger outlet as a driving gas A distribution ratio of an ejector for drawing in the refrigerant at the outlet of the evaporator and returning it to the condenser, and a flow rate of the refrigerant supplied from the heat exchanger outlet to the ejector and a refrigerant flow supplied to the expander from the heat exchanger outlet; A flow rate distribution ratio control mechanism that can be controlled is provided.

Embodiments of the present invention, advantages of the present invention, are described in detail below in conjunction with the attached drawings.

FIG. 1 is a schematic block diagram showing the whole system of the Rankine cycle which is the premise of the present invention. FIG. 2A is a schematic cross-sectional view of an expander pump in which the pump and the expander are integrated. FIG. 2B is a schematic cross-sectional view of a refrigerant pump. FIG. 2C is a schematic cross-sectional view of the expander. FIG. 3 is a schematic view showing the function of the refrigerant system valve. FIG. 4 is a schematic block diagram of a hybrid vehicle. FIG. 5 is a schematic perspective view of an engine. FIG. 6 is a schematic view of the arrangement of the exhaust pipe as viewed from below the vehicle. FIG. 7A is a characteristic diagram of a Rankine cycle operating region. FIG. 7B is a characteristic diagram of a Rankine cycle operating region. FIG. 8 is a timing chart showing how the hybrid vehicle 1 is accelerated while assisting the rotation of the engine output shaft by the expander torque. FIG. 9 is a timing chart showing a state of restart from the shutdown of the Rankine cycle. FIG. 10 is a schematic configuration diagram of an integrated cycle of the first embodiment of the present invention to which an ejector is added. FIG. 11 is a schematic cross-sectional view of the ejector. FIG. 12 is a schematic view showing Rankine cycle islanding operation. FIG. 13 is a schematic view showing the operation of the torque-assisted ejector air conditioner. FIG. 14 is a schematic view showing the operation of a torque assist-less ejector air conditioner. FIG. 15 is a schematic view showing the operation of the compressor air conditioner. FIG. 16A is a flowchart for describing control of the integration cycle of the first embodiment. FIG. 16B is a flowchart for describing control of the integration cycle of the first embodiment. FIG. 17 is a characteristic diagram of the radiator fan target rotational speed. FIG. 18 is a characteristic diagram of the target ejector supply flow rate. FIG. 19 is a characteristic diagram of the target ejector side opening degree. FIG. 20 is a characteristic diagram of the target pump rotational speed. FIG. 21 is a characteristic diagram of the target compressor drive amount. FIG. 22A is a flowchart for describing control of the integration cycle of the second embodiment. FIG. 22B is a flowchart for describing control of the integration cycle of the second embodiment. FIG. 23 is a characteristic diagram of the basic expander side opening degree of the second embodiment. FIG. 24 is a schematic configuration diagram of a hybrid vehicle. FIG. 25 is a layout view of the radiator and the condenser of the third embodiment. FIG. 26 is a schematic configuration diagram of an integration cycle of the fourth embodiment. FIG. 27 is a diagram showing an example of a circuit configuration that can be applied to the fifth embodiment. FIG. 28 is a diagram showing another example of the circuit configuration that can be applied to the fifth embodiment. FIG. 29 is a timing chart when control according to the fifth embodiment is performed.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

First Embodiment
FIG. 1 shows a schematic configuration diagram showing the whole system of Rankine cycle on which the present invention is premised. The Rankine cycle 31 of FIG. 1 is configured to share the refrigerant and the condenser 38 with the refrigeration cycle 51. Here, the cycle in which the Rankine cycle 31 and the refrigeration cycle 51 are integrated is referred to as an integrated cycle 30.

FIG. 4 is a schematic configuration diagram of the hybrid vehicle 1 on which the integrated cycle 30 is mounted. The integrated cycle 30 is a circuit (passage) through which the refrigerants of the Rankine cycle 31 and the refrigeration cycle 51 circulate, and a pump, an expander, a condenser and other components provided in the middle thereof, as well as a circuit of cooling water and exhaust. It refers to the whole system including (passage) etc.

In hybrid vehicle 1, engine 2, motor generator 81, and automatic transmission 82 are connected in series, and the output of automatic transmission 82 is transmitted to driving wheel 85 via propeller shaft 83 and differential gear 84. A first drive shaft clutch 86 is provided between the engine 2 and the motor generator 81. Also, one of the friction engagement elements of the automatic transmission 82 is configured as a second drive shaft clutch 87.

The first drive shaft clutch 86 and the second drive shaft clutch 87 are connected to the engine controller 71, and connection / disconnection (connection state) thereof is controlled in accordance with the driving condition of the hybrid vehicle. In the hybrid vehicle 1, as shown in FIG. 7B, when the vehicle speed is in the EV travel range where the efficiency of the engine 2 is low, the engine 2 is stopped, the first drive shaft clutch 86 is disconnected, and the second drive shaft clutch 87 is It connects and makes the hybrid vehicle 1 travel with only the driving force of the motor generator 81. On the other hand, when the vehicle speed deviates from the EV travel region and shifts to the Rankine cycle operation region, the engine 2 is driven to drive the Rankine cycle 31 (described later).

The engine 2 includes an exhaust passage 3, and the exhaust passage 3 includes an exhaust manifold 4 and an exhaust pipe 5 connected to a collecting portion of the exhaust manifold 4. The exhaust pipe 5 branches off from the bypass exhaust pipe 6 in the middle, and the exhaust pipe 5 of the section bypassed by the bypass exhaust pipe 6 is a waste heat recovery for performing heat exchange between the exhaust gas and the cooling water Vessel 22 is provided. The waste heat recovery unit 22 and the bypass exhaust pipe 6 are disposed between the underfloor catalyst 88 and the downstream sub-muffler 89 as a waste heat recovery unit 23 in which these are integrated as shown in FIG. 6.

First, an engine coolant circuit will be described based on FIG. The cooling water at about 80 to 90 ° C. that has left the engine 2 flows separately into the cooling water passage 13 passing through the radiator 11 and the bypass cooling water passage 14 bypassing the radiator 11. Thereafter, the two flows rejoin at the thermostat valve 15 which determines the distribution of the flow rate of the cooling water flowing through both

passages

13 and 14, and further return to the engine 2 through the cooling water pump 16. The coolant pump 16 is driven by the engine 2 and its rotational speed is in phase with the engine rotational speed.

When the coolant temperature is high, the thermostat valve 15 enlarges the valve opening on the coolant passage 13 side to relatively increase the amount of coolant passing through the radiator 11, and when the coolant temperature is low, the coolant passage The valve opening degree on the side 13 is reduced to relatively reduce the amount of cooling water passing through the radiator 11. In particular, when the coolant temperature is low before the engine 2 is warmed up, the radiator 11 is completely bypassed, and the entire amount of coolant flows on the bypass coolant passage 14 side. On the other hand, the valve opening on the bypass coolant passage 14 side is never fully closed. When the flow rate of the cooling water flowing through the radiator 11 increases, the flow rate of the cooling water flowing through the bypass cooling water passage 14 decreases as compared with the case where the entire amount of cooling water flows through the bypass cooling water passage 14 side. The thermostat valve 15 is configured so as not to stop completely. The bypass cooling water passage 14 bypassing the radiator 11 is branched from the cooling water passage 13 and directly connected to the heat exchanger 36 described later, and branched from the cooling water passage 13 to recover waste heat. And a second bypass coolant passage 25 connected to the heat exchanger 36 after passing through the vessel 22.

The bypass cooling water passage 14 is provided with a heat exchanger 36 which exchanges heat with the refrigerant of the Rankine cycle 31. The heat exchanger 36 is an integrated heater and superheater. That is, in the heat exchanger 36, the refrigerant passage 36c through which the refrigerant of the Rankine cycle 31 flows is a cooling water passage so that the two cooling

water passages

36a and 36b can exchange heat substantially between the refrigerant and the cooling water. It is provided adjacent to 36a and 36b. Furthermore, when looking through the heat exchanger 36, the

passages

36a, 36b, and 36c are configured such that the refrigerant and the coolant in the Rankine cycle 31 flow in opposite directions.

In detail, one cooling water passage 36 a located on the upstream (left in FIG. 1) side of the refrigerant of the Rankine cycle 31 is interposed in the first bypass cooling water passage 24. The heat exchanger left side portion including the coolant passage 36a and the coolant passage portion adjacent to the coolant passage 36a flows through the coolant passage 36c by directly introducing the coolant from the engine 2 into the coolant passage 36a. It is a heater for heating the refrigerant of the Rankine cycle 31.

The cooling water that has passed through the waste heat recovery unit 22 via the second bypass cooling water passage 25 is introduced to the other cooling water passage 36 b located on the downstream (right in FIG. 1) side with respect to the refrigerant of the Rankine cycle 31. The heat exchanger right portion (downstream side with respect to the refrigerant of the Rankine cycle 31) including the cooling water passage 36b and the refrigerant passage portion adjacent to the cooling water passage 36b Is introduced into the cooling water passage 36b to superheat the refrigerant flowing in the refrigerant passage 36c.

The cooling water passage 22 a of the waste heat recovery unit 22 is provided adjacent to the exhaust pipe 5. By introducing the cooling water at the outlet of the engine 2 into the cooling water passage 22a of the waste heat recovery unit 22, the cooling water can be heated to, for example, about 110 to 115 ° C. by high-temperature exhaust gas. The cooling water passage 22a is configured such that the exhaust gas and the cooling water flow in opposite directions when the entire waste heat recovery unit 22 is viewed.

A control valve 26 is interposed in the second bypass cooling water passage 25 provided with the waste heat recovery unit 22. The coolant temperature sensor at the outlet of the engine 2 so that the engine coolant temperature that indicates the temperature of the coolant inside the engine 2 does not exceed, for example, the allowable temperature (for example, 100 ° C.) for preventing engine efficiency deterioration and knocking. When the detected temperature 74 exceeds a predetermined value, the opening degree of the control valve 26 is decreased. When the engine water temperature approaches the allowable temperature, the amount of cooling water passing through the waste heat recovery unit 22 is reduced, so that the engine water temperature can be reliably prevented from exceeding the allowable temperature.

On the other hand, if the flow rate of the second bypass cooling water passage 25 decreases, the temperature of the cooling water rising by the waste heat recovery unit 22 rises too much and the cooling water is evaporated (boiled), the heat exchanger 36 In addition, the flow of the cooling water in the cooling water passage may be deteriorated and the temperature may be excessively increased. In order to avoid this, a bypass exhaust pipe 6 bypassing the waste heat recovery unit 22 and a thermostat valve 7 for controlling an exhaust passage amount of the exhaust recovery device 22 and an exhaust passage amount of the bypass exhaust pipe 6 are branched. It is provided in the department. That is, the valve opening degree of the thermostat valve 7 is the temperature of the cooling water leaving the waste heat recovery unit 22 so that the temperature of the cooling water leaving the waste heat recovery unit 22 does not exceed a predetermined temperature (eg boiling temperature 120 ° C.) Adjusted based on

The heat exchanger 36, the thermostat valve 7, and the waste heat recovery unit 22 are integrated as a waste heat recovery unit 23, and are disposed midway in the exhaust pipe below the floor approximately at the center in the vehicle width direction. The thermostat valve 7 may be a relatively simple temperature sensitive valve using a bimetal or the like, or may be a control valve controlled by a controller to which a temperature sensor output is input. Since the adjustment of the heat exchange amount from the exhaust gas to the cooling water by the thermostat valve 7 involves a relatively large delay, it is difficult to prevent the engine water temperature from exceeding the allowable temperature if the thermostat valve 7 is adjusted alone. However, since the control valve 26 of the second bypass cooling water passage 25 is controlled based on the engine water temperature (outlet temperature), the heat recovery amount can be rapidly reduced and the engine water temperature surely exceeds the allowable temperature. It can prevent. Further, if the engine water temperature has a margin up to the allowable temperature, heat exchange is performed until the temperature of the cooling water leaving the waste heat recovery unit 22 reaches a high temperature (for example, 110 to 115 ° C.) which exceeds the allowable temperature of the engine water temperature. To increase the amount of waste heat recovery. The coolant that has left the coolant passage 36 b is joined to the first bypass coolant passage 24 via the second bypass coolant passage 25.

If the temperature of the cooling water from the bypass cooling water passage 14 toward the thermostat valve 15 is sufficiently lowered by heat exchange with the refrigerant of the Rankine cycle 31 in the heat exchanger 36, for example, the cooling water passage 13 side of the thermostat valve 15 The valve opening degree of is decreased, and the amount of cooling water passing through the radiator 11 is relatively reduced. Conversely, when the temperature of the coolant flowing from the bypass coolant passage 14 toward the thermostat valve 15 is increased due to the Rankine cycle 31 not being operated, the valve opening on the coolant passage 13 side of the thermostat valve 15 is increased. The amount of cooling water passing through the radiator 11 is relatively increased. Based on the operation of the thermostat valve 15 as described above, the coolant temperature of the engine 2 is appropriately maintained, and heat is appropriately supplied (recovered) to the Rankine cycle 31.

Next, the Rankine cycle 31 will be described. Here, the Rankine cycle 31 is not a simple Rankine cycle, but is configured as part of an integrated cycle 30 integrated with the refrigeration cycle 51. In the following, the basic Rankine cycle 31 will be described first, and then the refrigeration cycle 51 will be mentioned.

The Rankine cycle 31 is a system that recovers the waste heat of the engine 2 as a refrigerant through the cooling water of the engine 2 and regenerates the recovered waste heat as power. The Rankine cycle 31 includes a refrigerant pump 32, a heat exchanger 36 as a superheater, an expander 37, and a condenser (condenser) 38, and each component is connected by refrigerant passages 41 to 44 through which a refrigerant (R 134a etc.) circulates. It is done.

The shaft of the refrigerant pump 32 is connected to the output shaft of the expander 37 on the same shaft, and the output (power) generated by the expander 37 drives the refrigerant pump 32 and the generated power is output from the engine 2 Supply to the crankshaft) (see FIG. 2A). That is, the shaft of the refrigerant pump 32 and the output shaft of the expander 37 are disposed parallel to the output shaft of the engine 2, and a belt 34 is disposed between the pump pulley 33 provided at the tip of the shaft of the refrigerant pump 32 and the crank pulley 2 a. (See Figure 1). A gear pump is used as the refrigerant pump 32 of the present embodiment, and a scroll expander is used as the expander 37 (see FIGS. 2B and 2C).

In addition, an electromagnetic clutch (hereinafter referred to as "expansion machine clutch") 35 is provided between the pump pulley 33 and the refrigerant pump 32, and the refrigerant pump 32 and the expansion machine 37 can be connected to and disconnected from the engine 2. (See Figure 2A). Therefore, the expander 37 is connected by connecting the expander clutch 35 when the output generated by the expander 37 exceeds the friction of the driving force of the refrigerant pump 32 and the rotating body (when the predicted expander torque is positive). The rotation of the engine output shaft can be assisted by the output generated by Fuel consumption can be improved by assisting the rotation of the engine output shaft using the energy obtained by waste heat recovery as described above. In addition, energy for driving the refrigerant pump 32 for circulating the refrigerant can also be provided by the recovered waste heat.

The refrigerant from the refrigerant pump 32 is supplied to the heat exchanger 36 via the refrigerant passage 41. The heat exchanger 36 exchanges heat between the coolant of the engine 2 and the refrigerant to vaporize and superheat the refrigerant.

The refrigerant from the heat exchanger 36 is supplied to the expander 37 via the refrigerant passage 42. The expander 37 is a steam turbine that converts heat into rotational energy by expanding a vaporized and superheated refrigerant. The power recovered by the expander 37 drives the refrigerant pump 32, is transmitted to the engine 2 via the belt transmission mechanism, and assists the rotation of the engine 2.

The refrigerant from the expander 37 is supplied to the condenser 38 via the refrigerant passage 43. The condenser 38 is a heat exchanger which performs heat exchange between the outside air and the refrigerant, cools the refrigerant, and liquefies the refrigerant. For this reason, the condenser 38 is disposed in parallel with the radiator 11 and is cooled by the radiator fan 12.

The refrigerant liquefied by the condenser 38 is returned to the refrigerant pump 32 through the refrigerant passage 44. The refrigerant returned to the refrigerant pump 32 is again sent to the heat exchanger 36 by the refrigerant pump 32, and circulates through the components of the Rankine cycle 31.

Next, the refrigeration cycle 51 will be described. The refrigeration cycle 51 is integrated with the Rankine cycle 31 in order to share the refrigerant circulating through the Rankine cycle 31, and the configuration itself of the refrigeration cycle 51 is simplified. That is, the refrigeration cycle 51 includes a compressor (compressor) 52, a condenser 38, and an evaporator (evaporator) 55.

The compressor 52 is a fluid machine that compresses the refrigerant of the refrigeration cycle 51 to a high temperature and a high pressure, and is driven by the engine 2. That is, as shown also in FIG. 4, the compressor pulley 53 is fixed to the drive shaft of the compressor 52, and the belt 34 is wound around the compressor pulley 53 and the crank pulley 2a. The driving force of the engine 2 is transmitted to the compressor pulley 53 via the belt 34, and the compressor 52 is driven. Further, an electromagnetic clutch (hereinafter referred to as a "compressor clutch") 54 is provided between the compressor pulley 53 and the compressor 52 so that the compressor 52 and the compressor pulley 53 can be connected and disconnected.

Returning to FIG. 1, the description will be continued. The refrigerant from the compressor 52 joins the refrigerant passage 43 via the refrigerant passage 56 and is then supplied to the condenser 38. The condenser 38 is a heat exchanger that condenses and liquefies the refrigerant by heat exchange with the outside air. The liquid refrigerant from the condenser 38 is supplied to the evaporator (evaporator) 55 via a refrigerant passage 57 branched from the refrigerant passage 44. The evaporator 55 is disposed in the case of the air conditioner unit, similarly to the heater core (not shown). The evaporator 55 is a heat exchanger that evaporates the liquid refrigerant from the condenser 38 and cools the conditioned air from the blower fan by the latent heat of evaporation at that time.

The refrigerant evaporated by the evaporator 55 is returned to the compressor 52 via the refrigerant passage 58. The mixing ratio of the conditioned air cooled by the evaporator 55 and the conditioned air heated by the heater core is changed according to the degree of opening of the air mix door, and is adjusted to the temperature set by the occupant.

In the integrated cycle 30 composed of the Rankine cycle 31 and the refrigeration cycle 51, various valves are appropriately provided in the middle of the circuit in order to control the refrigerant flowing in the cycle. For example, in order to control the refrigerant circulating through the Rankine cycle 31, a pump upstream valve 61 is provided in the refrigerant passage 44 connecting the refrigeration cycle branch point 45 and the refrigerant pump 32, and the heat exchanger 36 and the expander 37 are communicated. An expander upstream valve 62 is provided in the refrigerant passage 42 which is disposed. Further, a check valve 63 is provided in the refrigerant passage 41 connecting the refrigerant pump 32 and the heat exchanger 36 in order to prevent the backflow of the refrigerant from the heat exchanger 36 to the refrigerant pump 32. The refrigerant passage 43 connecting the expander 37 and the refrigeration cycle junction 46 is also provided with a check valve 64 for preventing the backflow of the refrigerant from the refrigeration cycle junction 46 to the expander 37. Further, an expander bypass passage 65 is provided which bypasses the expander 37 from the upstream of the expander upstream valve 62 and joins the upstream of the check valve 64, and a bypass valve 66 is provided in the expander bypass passage 65. Furthermore, a pressure regulating valve 68 is provided in the passage 67 that bypasses the bypass valve 66. An air conditioner circuit valve 69 is provided in the refrigerant passage 57 connecting the refrigeration cycle branch point 45 and the evaporator 55 also on the refrigeration cycle 51 side.

The four

valves

61, 62, 66, 69 are all electromagnetic on-off valves. The signal of the expander upstream pressure detected by the pressure sensor 72, the signal of the refrigerant pressure Pd at the outlet of the condenser 38 detected by the pressure sensor 73, the rotational speed signal of the expander 37, etc. are input to the engine controller 71 . The engine controller 71 controls the compressor 52 of the refrigeration cycle 51 and the radiator fan 12 based on the respective input signals in accordance with predetermined operation conditions, and the four electromagnetic on-off

valves

61, 62, 66. , 69 open and close control.

For example, the expander torque (regenerative power) is predicted based on the expander upstream pressure detected by the pressure sensor 72 and the expander rotational speed, and when the predicted expander torque is positive (the engine output shaft is assisted (When possible) and engage the expander clutch 35, and release the expander clutch 35 when the predicted expander torque is zero or negative. Compared with the case where the expander torque (regenerative power) is predicted from the exhaust temperature, the expander torque can be predicted with high accuracy, based on the sensor detection pressure and the expander rotational speed, and the expander torque generation state Accordingly, the expansion clutch 35 can be properly engaged and disengaged (see JP 2010-190185 A for details).

The four on-off

valves

61, 62, 66, 69 and the two

check valves

63, 64 are refrigerant system valves. The functions of these refrigerant valves are shown again in FIG.

In FIG. 3, the pump upstream valve 61 closes the refrigerant (including the lubricating component) to the Rankine cycle 31 by closing under a predetermined condition that the refrigerant tends to be biased to the circuit of the Rankine cycle 31 compared to the circuit of the refrigeration cycle 51. In order to prevent the deviation of the pressure, as described later, the circuit of the Rankine cycle 31 is closed in cooperation with the check valve 64 downstream of the expander 37. The expander upstream valve 62 shuts off the refrigerant passage 42 when the refrigerant pressure from the heat exchanger 36 is relatively low, so that the refrigerant from the heat exchanger 36 can be held to a high pressure. It is. By this, even if the expander torque can not be obtained sufficiently, it is possible to accelerate the heating of the refrigerant and to shorten, for example, the time until the Rankine cycle 31 is restarted (the regeneration can be actually performed). The bypass valve 66 is opened so that the refrigerant pump 32 can be operated after bypassing the expander 37 when the amount of refrigerant present on the Rankine cycle 31 side is not sufficient, for example, when the Rankine cycle 31 is started. To reduce the start-up time of the Rankine cycle 31. By operating the refrigerant pump 32 after bypassing the expander 37, the refrigerant temperature at the outlet of the condenser 38 or at the inlet of the refrigerant pump 32 changes from the boiling point considering the pressure at that portion to a predetermined temperature difference (subcool temperature SC If the above-mentioned state of reduction is realized, the Rankine cycle 31 is ready to be supplied with a sufficient amount of liquid refrigerant.

The check valve 63 upstream of the heat exchanger 36 is for maintaining the refrigerant supplied to the expander 37 at high pressure in cooperation with the bypass valve 66, the pressure control valve 68 and the expander upstream valve 62. Under conditions where the regenerative efficiency of the Rankine cycle 31 is low, the operation of the Rankine cycle 31 is stopped, and the circuit is closed over the sections before and after the heat exchanger 36 to raise the refrigerant pressure during stoppage. The Rankine cycle 31 can be restarted promptly by using it. The pressure control valve 68 has a role of a relief valve that opens when the pressure of the refrigerant supplied to the expander 37 becomes too high and releases the too high refrigerant.

The check valve 64 downstream of the expander 37 is for preventing the bias of the refrigerant to the Rankine cycle 31 in cooperation with the above-described pump upstream valve 61. If the engine 2 is not warmed up immediately after the start of the operation of the hybrid vehicle 1, the Rankine cycle 31 may become lower temperature than the refrigeration cycle 51, and the refrigerant may be biased to the Rankine cycle 31 side. Although the probability of deviation to the Rankine cycle 31 side is not so high, for example, because the cooling capacity is most required in the situation where it is desirable to quickly cool the vehicle interior immediately after the start of vehicle operation in summer, slight uneven distribution of refrigerant is eliminated. There is a demand to secure the refrigerant of the refrigeration cycle 51. Therefore, in order to prevent uneven distribution of the refrigerant on the Rankine cycle 31 side, a check valve 64 is provided.

The compressor 52 does not have a structure that allows the refrigerant to freely pass when the driving is stopped, and can prevent the bias of the refrigerant to the refrigeration cycle 51 in cooperation with the air conditioner circuit valve 69. This will be described. When the operation of the refrigeration cycle 51 is stopped, the refrigerant may move from the relatively high temperature Rankine cycle 31 side in steady operation to the refrigeration cycle 51 side, and the refrigerant circulating in the Rankine cycle 31 may run short. In the refrigeration cycle 51, immediately after the cooling is stopped, the temperature of the evaporator 55 is low, and the refrigerant tends to be accumulated in the evaporator 55 having a relatively large volume and a low temperature. In this case, the movement of the refrigerant from the condenser 38 to the evaporator 55 is shut off by stopping the driving of the compressor 52, and the air conditioner circuit valve 69 is closed to prevent the refrigerant from being unevenly distributed to the refrigeration cycle 51.

FIG. 5 is a schematic perspective view of the engine 2 showing a package of the entire engine 2. What is characteristic in FIG. 5 is that the heat exchanger 36 is disposed vertically above the exhaust manifold 4. By disposing the heat exchanger 36 in the space vertically above the exhaust manifold 4, the mountability of the Rankine cycle 31 on the engine 2 is improved. Further, the engine 2 is provided with a tension pulley 8.

Next, a basic operation method of the Rankine cycle 31 will be described with reference to FIGS. 7A and 7B.

7A and 7B are operation region diagrams of the Rankine cycle 31. FIG. FIG. 7A shows the operating region of the Rankine cycle 31 when the horizontal axis is the outside air temperature, and the vertical axis is the engine water temperature (cooling water temperature). FIG. 7B shows the operating region of the Rankine cycle 31 when the horizontal axis is the engine rotational speed and the vertical axis is the engine torque (engine load).

7A and 7B, the Rankine cycle 31 is operated when predetermined conditions are satisfied, and the Rankine cycle 31 is operated when both of these conditions are satisfied. In FIG. 7A, the operation of the Rankine cycle 31 is stopped in the low water temperature region where warm-up of the engine 2 is prioritized and the high outside air temperature region where the load of the compressor 52 increases. During warm-up where the exhaust gas temperature is low and the recovery efficiency is poor, the coolant temperature is raised promptly by not operating the Rankine cycle 31 rather. At high outside air temperatures where high cooling capacity is required, the Rankine cycle 31 is stopped to provide the refrigeration cycle 51 with sufficient refrigerant and cooling capacity of the condenser 38.

In FIG. 7B, since the hybrid vehicle is targeted, the operation of the Rankine cycle 31 is stopped in the EV travel region and the region on the high rotational speed side where the friction of the expander 37 increases. Since it is difficult to make the expander 37 a highly efficient structure with little friction at all rotational speeds, in the case of FIG. 7B, the friction is small and highly efficient in the engine rotational speed region where the operation frequency is high, The expander 37 is configured (dimensions and the like of each part of the expander 37 are set).

FIG. 8 is a timing chart showing, as a model, how the hybrid vehicle 1 accelerates while the rotation of the engine output shaft is assisted by the expander torque. Note that on the right side of FIG. 8, a state in which the operating state of the expander 37 changes at this time is shown on the expander torque map. Of the range divided by the contour line of the expander torque map, the expander rotational speed is low and the expander upstream pressure is high (upper left) is the largest expander torque and the expander rotational speed is high, the expander upstream pressure As the lower the value (the lower right), the expander torque tends to decrease. In particular, the range of the hatched portion represents a region where the expander torque is negative on the premise that the refrigerant pump is driven and the load is applied to the engine.

The constant speed traveling is continued until the timing t1 at which the driver depresses the accelerator pedal, and the expander 37 generates positive torque, and rotation assist of the engine output shaft by the expander torque is performed.

After timing t1, the rotational speed of the expander 37, that is, the rotational speed of the refrigerant pump 32, increases in proportion to the engine rotational speed, but the increase in exhaust temperature or coolant temperature is delayed with respect to the increase in engine rotational speed. Have. Therefore, the ratio of recoverable heat amount to the amount of refrigerant increased due to the increase of the rotational speed of the refrigerant pump 32 decreases.

Therefore, as the expander rotational speed increases, the refrigerant pressure upstream of the expander decreases and the expander torque decreases.

When the expander torque can not be obtained sufficiently (for example, at the timing of t2 when it becomes near zero) due to the reduction of the expander torque, the expander upstream valve 62 is switched from the open state to the closed state to deteriorate the regeneration efficiency ( The phenomenon in which the expander 37 is dragged to the engine 2 in reverse with the excessive reduction of expander torque is avoided.

After switching the expander upstream valve 62 from the open state to the closed state, the expander clutch 35 is switched from connection (engagement) to disconnection (release) at timing t3. The refrigerant pressure in the upstream of the expander is sufficiently lowered by disconnecting the expander clutch 35 by delaying the disconnection timing of the expander clutch 35 somewhat later than the timing at which the expander upstream valve 62 is switched from the open state to the closed state. It is possible to prevent the expander 37 from being over-rotated. Further, by supplying a larger amount of refrigerant into the heat exchanger 36 by the refrigerant pump 32 and effectively heating the refrigerant even while the Rankine cycle 31 is stopped, the operation resumption of the Rankine cycle 31 can be smoothly performed. There is.

After timing t3, the expander upstream pressure rises again due to the increase of the heat release amount of the engine 2, and at timing of t4, the expander upstream valve 62 is switched from the closed state to the open state to supply the refrigerant to the expander 37 Is resumed. In addition, the expander clutch 35 is connected again at the timing of t4. Reconnection of the expander clutch 35 restarts the rotation assist of the engine output shaft by the expander torque.

FIG. 9 shows a state in which the Rankine cycle 31 is restarted in a mode different from that of FIG. 8 (control of timing t4) from the operation stop of the Rankine cycle with the expander upstream valve 62 closed and the expander clutch 35 disconnected. Is a timing chart showing the model.

When the driver depresses the accelerator pedal at the timing of t11, the accelerator opening degree increases. At the timing of t11, the operation of the Rankine cycle 31 is stopped. For this reason, the expander torque is maintained at zero.

As the engine rotational speed increases from timing t11, the heat release amount of the engine 2 increases, and the increase in the heat release amount raises the temperature of the coolant flowing into the heat exchanger 36, and the temperature of the refrigerant in the heat exchanger 36 Will rise. Since the expander upstream valve 62 is closed, the refrigerant pressure upstream of the expander upstream valve 62, that is, the expander upstream pressure, is increased by the increase of the refrigerant temperature by the heat exchanger 36 (t11 to t12).

The change in the operating state switches the Rankine cycle non-operating range to the Rankine cycle operating range. When the expander upstream valve 62 is not present and the shift to the Rankine cycle operation region is made, the expander clutch 35 is immediately switched from the disconnected state to the connected state, and the expander 37 is connected to the engine output shaft. A torque shock occurs when 37 is a load on the engine 2.

On the other hand, in FIG. 9, when switching to the Rankine cycle operating region, the expander upstream valve 62 is not switched from the closed state to the open state immediately. That is, even after the shift to the Rankine cycle operation region, the closed state of the expander upstream valve 62 is continued.

It is determined that the expander 37 can be operated (driven) at a timing of t12 when the differential pressure between the expander upstream pressure and the expander downstream pressure increases and reaches a predetermined pressure or more, and the expansion valve upstream valve 62 is closed Switch to open state. By switching the expansion valve upstream valve 62 to the open state, the refrigerant having a predetermined pressure is supplied to the expander 37, and the expander rotational speed rapidly increases from zero.

The expander clutch 35 is switched from the disconnected state to the connected state at time t13 when the expander rotational speed reaches the engine rotational speed due to the increase in the expander rotational speed. If the expander clutch 35 is connected before the expander 37 sufficiently increases the rotational speed, the expander 37 becomes an engine load and a torque shock may occur. On the other hand, the expansion machine clutch 35 becomes an engine load by connecting the expansion machine clutch 35 at a timing of t13 when the rotational speed difference from the engine output shaft disappears, and the expansion machine clutch 35 is engaged. Can also prevent torque shock associated with

In the prior art, when the waste heat of the engine is sufficiently obtained, the energy is externally supplied to drive the pump to supply the refrigerant to the heat exchanger, and the ejector overheats by the waste heat to drive the refrigeration cycle. When the waste heat is insufficient, the pump is stopped and the compressor is driven by the engine to operate the refrigeration cycle. However, in the conventional apparatus, in order to obtain a high pressure refrigerant for driving the ejector, it is necessary to supply energy from the outside to drive the pump, and driving the pump deteriorates fuel consumption.

Therefore, in the first embodiment, even if an ejector is added, in order to obtain a high pressure refrigerant for driving the ejector, the pump does not have to be driven by supplying energy from the outside. This will be described with reference to FIG. 10 shows a configuration in which an ejector 92 is added to the configuration shown in FIG. 1 and the same parts as in FIG. 1 are given the same reference numerals.

As shown in FIG. 10, a refrigerant passage 91 for bypassing the compressor 52 is provided. That is, a refrigerant passage 91 which branches from the refrigerant passage 58 connecting the outlet of the evaporator 55 and the compressor 52 and joins the refrigeration cycle junction 46 is provided. An ejector 92 is interposed in the refrigerant passage 91. In the refrigerant passage 91 between the branch point of the refrigerant passage 91 and the ejector 92, a check valve 99 is interposed for blocking the flow of the refrigerant from the ejector 92 to the branch point of the refrigerant passage 91.

The above-described ejector 92 is a device capable of creating a near vacuum state from fluid without mechanical movement such as a pump. The ejector 92, as shown in FIG. 11, includes a chamber 93 surrounded by the periphery, a suction port 94 opened to the chamber 93, a nozzle 95 facing the chamber 93, and a diffuser 96. In the chamber 93, the nozzle 95 and the diffuser 96 face each other at an appropriate distance.

The refrigerant passage is connected as follows to the ejector 92 configured as described above. That is, in FIG. 10, the refrigerant passage 97 is branched from the refrigerant passage 42 close to the outlet of the heat exchanger 36, and the branched refrigerant passage 97 is connected to the nozzle inlet 95a.

The branch portion of the branch refrigerant passage 97 is provided with an electromagnetic flow control valve 98 capable of adjusting the distribution ratio of the flow rate of the refrigerant flowing to the expander 37 and the flow rate of the refrigerant flowing to the ejector 92. Here, as the control amount of the flow control valve 98, the "ejector side opening degree" and the "expansion unit side opening degree" are introduced. For example, when the ejector-side opening degree is zero, all the refrigerant exiting from the outlet of the heat exchanger 36 does not flow through the branch refrigerant passage 97, and when the ejector-side opening degree is maximized, it exits from the outlet of the heat exchanger 36 All of the refrigerant flows in the branched refrigerant passage 97. On the other hand, when the expander side opening degree is zero, all the refrigerant at the heat exchanger outlet does not flow through the refrigerant passage 42, and when the expander side opening degree is maximized, the refrigerant leaving the outlet of the heat exchanger 36 All flow through the refrigerant passage 42. That is, when the ejector side opening degree is zero, the expander side opening degree is maximum, and when the ejector side opening degree is gradually increased from zero, the expander side opening degree gradually decreases from the maximum. Then, when the ejector side opening degree is maximized, the expander side opening degree becomes zero.

As described above, the relationship between the two openings in the flow control valve 98 of the present embodiment is a relationship in which the remaining openings are uniquely determined by determining one of the openings. Therefore, the flow control valve 98 may be controlled by either the ejector side opening degree or the expander side opening degree. Here, the ejector side opening degree is controlled. Thus, since the refrigerant circuit is configured such that the ejector 92 is in parallel with the expander 37, the refrigerant can be arbitrarily diverted to the ejector side and the expander side, and the driving of the refrigerant pump 32 and the compressor 52 Driving can be performed as desired.

The refrigerant passage 91 on the evaporator 55 side is connected to the suction port 94, and the refrigerant passage 91 on the merging portion 46 side with the refrigerant passage 43 is connected to the ejector outlet 96a.

Here, the operation of the ejector 92 will be described. When a high pressure gas refrigerant is injected as a drive gas from the nozzle 95 toward the chamber 93, the gas refrigerant forms a low pressure supersonic flow and travels to the inlet of the diffuser 96. A negative static pressure is generated in the chamber 93 by the flow of the gas refrigerant, and the interior of the chamber 93 is in a state close to vacuum. Due to the static pressure and the viscosity of the gas refrigerant, the gas refrigerant from the evaporator 55 is drawn as a suction gas into the gas refrigerant flow jumping into the inlet of the diffuser 96. The gas refrigerant supplied to the nozzle 95 and the gas refrigerant sucked from the suction port 94 are mixed in the front half of the diffuser 96, and are discharged toward the diffuser outlet 96a while reducing the pressure and pressurizing in the rear half.

In the configuration in which the ejector 92 is added to the combined cycle 30, during the operation of the Rankine cycle 31, the ejector 92 is driven by guiding a part of the refrigerant flowing through the refrigerant passage of the Rankine cycle 31 to the ejector 92 as a driving gas. Then, the refrigeration cycle 51 can be operated. With such a configuration, it is not necessary to supply energy from the outside to drive the pump in order to obtain the high pressure refrigerant for driving the ejector as in the conventional device. Here, "operating the refrigeration cycle 51" means that the refrigerant is circulated in the refrigerant passage of the refrigeration cycle 51 (as a result, the cooling of the air conditioner is effective).

Thus, by adding the ejector 92, in the present embodiment, <1> Rankine cycle alone operation, <2> operation of the ejector air conditioner with torque assist, <3> operation of the ejector air conditioner without torque assist, <4> It became possible to use properly the four operations of compressor air conditioner operation. Here, "the operation of the ejector air conditioner" means that the refrigeration cycle 51 is operated by driving the ejector 92 without using the compressor 52. Further, “the operation of the compressor air conditioner” means that the refrigeration cycle 51 is operated by driving the compressor 52 without using the ejector 92. Hereinafter, each of the above operations will be described.

<1> Rankine cycle sole operation The Rankine cycle sole operation is performed when there is no air conditioning request (cooling request). As shown in FIG. 12, the ejector side opening degree of the flow control valve 98 is made zero (see the broken line), and the ejector 92 is not driven and the driving of the ejector 92 is stopped without supplying the gas refrigerant to the ejector 92.

The refrigerant is evaporated and superheated by the waste heat of the engine 2 by the heat exchanger 36, and all the gas refrigerant exiting from the outlet of the heat exchanger 36 is supplied to the expander 37 via the refrigerant passage 42 (see thick solid line) The expander 37 is rotationally driven by the pressure energy of the gas refrigerant. The refrigerant pump 32 is driven by the torque (output) generated by the expander 37 to circulate the refrigerant, and the Rankine cycle 31 is operated. Here, "operating the Rankine cycle 31" means circulating the refrigerant in the refrigerant passage of the Rankine cycle 31 (as a result, energy is recovered from the waste heat). When the torque generated by the expander 37 exceeds the driving force of the refrigerant pump 32, the expander clutch 35 is connected and the Rankine cycle 31 is operated to assist the rotation of the engine output shaft to improve the fuel efficiency.

<2> Operation of Ejector Air Conditioner with Torque Assist A torque assist can be performed when there is an air conditioner request such as during high-speed cruising mainly due to air conditioner request and there is sufficient torque generated by the expander 37. Operate the ejector air conditioner. As shown in FIG. 13, the ejector-side opening degree of the flow control valve 98 is controlled, and the gas refrigerant exiting from the outlet of the heat exchanger 36 is divided and supplied to the expander 37 and the ejector 92 to rotate the expander 37. While driving, the ejector 92 is driven.

The refrigerant pump 32 is driven by the torque (output) of the expander 37 to circulate the refrigerant, and the Rankine cycle 31 is operated. A part of the refrigerant circulating in the refrigerant passage of the Rankine cycle 31 is guided to the ejector 92 to drive the ejector 92, and the refrigerant is also circulated in the refrigerant passage of the refrigeration cycle 51. The refrigeration cycle 51 is operated without driving the compressor 52 to perform air conditioning of the vehicle interior. The driving of the compressor 52 is a load on the engine 2 and the fuel efficiency is deteriorated accordingly. However, if the refrigeration cycle 51 is operated by driving the ejector 92 during the operation of the Rankine cycle 31, It can control the deterioration.

Even if the refrigerant pump 32 is driven, the expander clutch 35 is connected when the expander torque remains, and the rotation of the engine output shaft is assisted by the expander torque remaining even if the refrigerant pump 32 is driven to improve the fuel efficiency. Let

<3> Operation of the ejector air conditioner without torque assist When there is an air conditioner requirement, such as during idle stop or low load, and the torque generated by the expander 37 is not sufficient and torque assist can not be performed, the ejector air conditioner without torque assist Do the driving. The difference from the operation of the torque-assisted ejector air conditioner described above in <2> is only that torque assist is not performed. That is, as shown in FIG. 14, the expander clutch 35 is disconnected, the ejector side opening degree of the flow control valve 98 is controlled, and the expander torque is used only to drive the refrigerant pump 32 without torque assist. The Rankine cycle 31 is operated by using it. The ejector 92 is driven by the gas refrigerant obtained by the operation of the Rankine cycle 31 to operate the refrigeration cycle 51. Even after a transition to idle stop for a while or at a low vehicle speed, the refrigeration cycle 51 can be operated only with engine waste heat without using the power (compressor 52).

<4> Operation of Compressor Air Conditioner After the operation of the ejector air conditioner without torque assist described above <3> can not be performed during idle stop or low load, the compressor air conditioner is operated. As shown in FIG. 15, the ejector side opening degree of the flow control valve 98 is made zero, and the pump upstream valve 61 (see FIG. 10) is closed to stop the supply of the refrigerant to the expander 37 and the ejector 92. The operation of the Rankine cycle 31 and the driving of the ejector 92 are stopped. If idle stop is in progress, current is supplied to the motor to drive the compressor 52 by the motor, and when the load is low, the compressor clutch 54 is connected and the engine 52 drives the compressor 52 to operate the refrigeration cycle 51 , Air conditioning the vehicle interior.

Next, this control performed by the engine controller 71 will be specifically described with reference to the flowcharts of FIGS. 16A and 16B. The flows of FIG. 16A and FIG. 16B are executed at a constant cycle (for example, every 10 ms).

In FIG. 16A, in step S1, it is determined whether there is an air conditioner request (compressor drive request). If there is no air conditioning request, the process proceeds to step S2 to stop the drive of the ejector 92, and the flow control valve 98 is controlled so that the ejector side target opening becomes zero.

In step S3, it is determined whether the engine 2 is in the idle stop state or the low load state. In the hybrid vehicle 1, for example, when under the EV traveling condition, it is determined that the idle stop state is established. In this case, particularly, the idle stop state in the hybrid vehicle is used as a condition, but the entire control for stopping the engine such as a fuel cut or a coast stop (engine stop state) can be used as a condition. Further, when the SOC (charging state) of the battery is insufficient and the engine 2 is operated for charging, it is determined that the engine 2 is in a low load state.

When the engine 2 is in the idle stop state or the low load state, it is determined that the Rankine cycle 31 can not be operated. At this time, the process proceeds to step S4, and the expander clutch 35 is disconnected. In order to stop the drive of the expander 37, the expander upstream valve 62 is fully closed, and the bypass valve 66 is fully open, and the expander 37 is bypassed to allow all the refrigerant to flow. Although not shown in the flow, both the expander upstream valve 62 and the bypass valve 66 are fully closed so as to confine the refrigerant in the heat exchanger 36 (maintain the pressure) in preparation for the next restart of operation. It can also be done.

On the other hand, when the engine 2 is not in the idle stop state or the low load state in step S3, it is determined that the Rankine cycle 31 can be operated, and the process proceeds to step S5. Step S5 is a part for performing the Rankine cycle solo operation shown in FIG. That is, the expander clutch 35 is connected, the expander upstream valve 62 is fully opened, the bypass valve 66 is fully closed, and all the gas refrigerant exiting from the outlet of the heat exchanger 36 is allowed to flow to the expander 37. As a result, when the expander 37 is rotationally driven and the torque (output) regenerated by the expander 37 exceeds the drive torque of the refrigerant pump 32, the torque that exceeds this is transmitted to the engine output shaft through the belt transmission mechanism. The power is transmitted to assist the rotation of the engine output shaft.

When the air conditioner request is made in step S1, the process proceeds to step S6, and the rotational speed of the radiator fan 12 is controlled in accordance with the table shown in FIG. As shown in FIG. 17, the radiator fan target rotational speed is zero when the vehicle speed is equal to or higher than a second predetermined value VSP2. This is because it is not necessary to drive the radiator fan 12 because a sufficient traveling wind can be obtained for the condenser 38 in the vehicle speed region above the second predetermined value VSP2. The radiator fan target rotational speed increases as the vehicle speed decreases below the second predetermined value VSP2, and becomes a constant value (positive value) when the vehicle speed is equal to or lower than the first predetermined value VSP1 (VSP1 <VSP2). This is because sufficient traveling wind can not be obtained for the condenser 38 in the vehicle speed range less than the second predetermined value VSP2, so that the condenser 38 needs to be cooled by the air from the radiator fan 12. The rotational speed of the radiator fan 12 is set in consideration of the heat radiation of both the refrigeration cycle 51 and the Rankine cycle 31.

In the flow not shown, according to the radiator fan target rotational speed, an amount of current to be supplied to a motor (not shown) for driving the radiator fan 12 is set, and the set current is supplied to the motor to rotate the radiator fan 12 .

In step S7, as in step S3, it is determined whether the engine 2 is in the idle stop state (engine stop state) or in the low load state. When the engine 2 is not in the idle stop state or the low load state, it is determined that the operation of the Rankine cycle 31 can be performed, and the process proceeds to step S8.

In step S8, the target ejector is searched by searching the map shown in FIG. 18 from the air conditioner set temperature and the heat release amount calculated based on the capacity of the condenser 38, for example, the vehicle speed, the radiator fan rotational speed, the outside air temperature and the like. Calculate the supply flow rate. As shown in FIG. 18, the target ejector supply flow rate decreases as the heat release amount increases under the condition that the air conditioner set temperature is constant, and increases as the air conditioner set temperature decreases when the heat release amount is constant.

In step S9, the target ejector side opening degree of the flow control valve 98 is calculated by searching the map shown in FIG. 19 from the target ejector supply flow rate calculated in step S8. As shown in FIG. 19, the target ejector side opening degree of the flow control valve 98 is larger as the target ejector supply flow rate is larger.

In step S10, the flow control valve 98 is controlled so that the calculated target ejector side opening degree is obtained.

In step S11, it is determined whether or not the torque assist of the engine 2 is possible, that is, whether or not a sufficient amount of expander torque can be obtained even if the refrigerant pump 32 is driven. Whether or not the expander torque sufficient for torque assist can be obtained can be determined based on the amount of waste heat recovery, the amount of heat radiation, and the air conditioner requirement. If the engine load is relatively low and the amount of waste heat recovery is small, the vehicle speed is low (running wind is small) or the outside temperature is high, etc., the amount of torque assist can be used when the amount of heat release is small Will be less. In addition, even when the deviation between the air conditioner set temperature and the actual vehicle interior temperature is large and the air conditioner demand is large, the amount of torque assist can be reduced. If torque assist is possible, the process proceeds to step S12, and if it is impossible, the process proceeds to step S13.

In step S12, to perform torque assist by driving the Rankine cycle 31, the expander clutch 35 is connected, the expander upstream valve 62 is fully opened, and the bypass valve 66 is fully closed. The gas refrigerant coming out of the outlet of is flowed to the expander 37. Step S12 is a portion for operating the torque-assisted ejector air conditioner shown in FIG.

On the other hand, in step S13, since the torque assist is not performed, the expander clutch 35 is disconnected, and the refrigerant pump 32 is driven by the expander torque by the operation of the Rankine cycle 31, so the expander upstream valve 62 is fully opened and bypassed. With the valve 66 fully closed, the gas refrigerant exiting from the outlet of the heat exchanger 36 is allowed to flow to the expander 37. Step S13 is a portion for operating the ejector air conditioner without torque assist shown in FIG.

By the way, when the vehicle speed is low, an expander torque sufficient to obtain the output of the refrigerant pump 32 corresponding to the flow rate of the refrigerant necessary for driving the ejector 92 can be obtained by rotating the radiator fan 12 (step S6 and FIG. 17). reference). Although energy is required to rotate the radiator fan 12, the regenerative energy from the waste heat recovery contributes to the expander torque, so that the energy for driving the compressor 52 of the refrigeration cycle 51 (by the power or electric power of the engine 2) Also, the energy for rotating the radiator fan 12 is smaller. Therefore, even when the radiator fan 12 is rotated, the operation of the ejector air conditioner is superior in total efficiency to the operation of the compressor air conditioner.

When the engine 2 is in the idle stop state or the low load state in step S7 of FIG. 16A, the process proceeds to step S15 of FIG. 16B. Basically, when the engine 2 is in the idle stop state (engine stop state) or low load state, the ejector air conditioner can not be operated, but immediately after the idle stop state or low load state, the ejector air conditioner is operated by residual heat. Can be done. Therefore, the operation of the ejector air conditioner is continued for a while, and when the operation of the ejector air conditioner becomes impossible, the operation is switched to the operation of the compressor air conditioner (compressor independent drive).

In step S15, it is determined whether or not the shift to compressor-only drive has been completed. For example, when the compressor single drive flag = 1, it is determined that the shift to the compressor single drive is completed, and when the compressor single drive flag = 0, it is determined that the shift to the compressor single drive is not completed. If it is determined that the compressor independent drive flag is 0, that is, it is determined that the compressor alone drive has not been shifted, the process proceeds to step S16.

Steps S16 to S21 are parts for operating the ejector air conditioner without torque assist shown in FIG. In step S16, the target ejector supply flow rate is calculated as in step S8. That is, the target ejector supply flow rate is obtained by searching the map shown in FIG. 18 from the air conditioner set temperature and the heat release amount calculated based on the capacity of the condenser 38, for example, the vehicle speed, the radiator fan rotational speed, the outside air temperature and the like. Calculate

In step S17, a target pump rotational speed is calculated by searching a table shown in FIG. 20 from the target ejector supply flow rate calculated in step S16. The target pump rotational speed is a target rotational speed of the refrigerant pump 32 required to obtain a target ejector supply flow rate. The target pump rotational speed is proportional to the target ejector supply flow rate, as shown in FIG. The target pump rotational speed is calculated because the pump rotational speed of the refrigerant pump 32 decreases in the operation of the ejector air conditioner using residual heat, so the degree of decrease of the actual pump rotational speed by comparing with the actual pump rotational speed To reduce the ejector-side opening degree of the flow control valve 98 (increase the expander-side opening degree) according to the degree of decrease.

In step S18, the actual rotational speed of the refrigerant pump 32 and the target pump rotational speed are compared. The actual rotational speed of the refrigerant pump 32 is detected by a pump rotational speed sensor 75 (see FIG. 10). When the actual rotational speed of the refrigerant pump 32 is higher than the target pump rotational speed, it is necessary to reduce the flow rate of the refrigerant flowing to the expander 37 to reduce the actual rotational speed of the refrigerant pump 32 to the target pump rotational speed. Therefore, in this case, the process proceeds to step S19, and the target ejector side opening degree of the flow control valve 98 is corrected to the increase side so that the refrigerant flow rate flowing to the ejector 92 increases (decreases the expander side).

In step S20, the flow control valve 98 is controlled to obtain the corrected target ejector side opening degree. In step S21, since the torque assist is not performed and the Rankine cycle 31 is operated, the expander clutch 35 is disconnected, the expander upstream valve 62 is fully opened, and the bypass valve 66 is fully closed. The gas refrigerant coming out of the outlet of is flowed to the expander 37. In this case, even if the expander torque drives the refrigerant pump 32, even if it generates a surplus, the torque assist is not performed, and the refrigerant used for assist is reduced and diverted to the ejector 92 side. Increase the refrigerant. This makes it possible to improve the effectiveness of the air conditioner (cooling) and prolong the duration.

When the actual rotation speed of the refrigerant pump 32 is less than the target pump rotation speed in step S18, the refrigerant flow rate flowing to the expander 37 is increased to increase the expander rotation speed, and the refrigerant pump 32 moves integrally with the expander 37. Needs to be raised to the target pump rotational speed. In this case, the process proceeds to step S22, and the target ejector side opening degree of the flow control valve 98 is corrected to the decrease side so that the expander side flow rate increases.

In step S23, auxiliary control by the compressor 52 is performed based on the table shown in FIG. Here, when the compressor 52 is driven by the drive of the engine 2, the compressor 52 can not be driven in the idle stop state in which the engine 2 is stopped. Therefore, as shown in FIG. 24, the compressor 52 is driven by the motor 101 so that the compressor assist can be performed when the process proceeds to step S23 in the idle stop state (without restarting the engine 2). It may be

The reason for performing the auxiliary control by the compressor 52 will be described. The driving condition for operating the ejector air conditioner without torque assist here is when it is in an idle stop state (engine stop state) or a low load state where it is difficult to obtain sufficient cooling capacity. If the actual rotational speed of the refrigerant pump 32 does not reach the target rotational speed, the expansion device opening degree of the flow control valve 98 may be increased, so that the flow rate on the ejector side may be insufficient. In such a case, the compressor 52 is driven within the range in which the total efficiency does not deteriorate, and the operation of the ejector air conditioner is continued.

As a result, when proceeding to steps S18, S22 and S23, both the operation of the non-torque ejector air conditioner shown in FIG. 14 and the operation of the compressor air conditioner shown in FIG. 15 are performed in an overlapping manner.

The auxiliary control by the compressor 52 will be specifically described. As shown in FIG. 21, the target compressor drive amount, that is, the target motor current amount has a positive value in a region where the target ejector side opening degree is equal to or less than the second predetermined value E2. This is due to the following reason. That is, in the region where the target ejector side opening degree is equal to or less than the second predetermined value E2, the refrigerant supply to the ejector 92 is insufficient, the ejector 92 does not operate sufficiently, and the cooling capacity falls. Therefore, when the refrigerant supply to the ejector 92 is insufficient, a current is supplied to the motor 101 (see FIG. 24) to drive the compressor 52 to increase the cooling capacity.

The degree to which the cooling capacity decreases in the region where the target ejector side opening degree is equal to or less than the second predetermined value E2 can be known in advance, so the characteristics of the target compressor drive amount shown in FIG. When the process proceeds to step S23 when the load is low, the target compressor driving amount shown in FIG. 21 is the amount of current to be supplied to the compressor clutch 54.

On the other hand, in the region where the target ejector side opening exceeds the second predetermined value E2, the compressor 52 is not driven with the target compressor drive amount being zero. This is because in the region, sufficient cooling capacity can be obtained by driving only the ejector 92 (that is, operation of the ejector air conditioner without torque assist).

In step S24, the evaporator temperature is compared with the target temperature. The temperature of the evaporator 55 is detected by a temperature sensor 76 (see FIG. 10). When the evaporator temperature is equal to or lower than the target temperature, it is determined that sufficient cooling capacity is obtained by adding the operation of the compressor air conditioner to the operation of the torque assist non-ejector air conditioner or to the operation of the torque assist non ejector air conditioner. That is, it is determined that it is not necessary to shift to the operation of the compressor air conditioner, and the process proceeds to steps S20 and S21, and the control of steps S20 and S21 is performed.

On the other hand, when the evaporator temperature is higher than the target temperature in step S24, it is determined that it is necessary to shift to the operation of the compressor air conditioner. In this case, the process proceeds to steps S25 to S27.

Steps S25 to S27 are portions for performing the compressor air conditioner operation shown in FIG. First, at step S25, the compressor single drive flag is set to 1 and a current is supplied to the motor 101 to drive the compressor 52 or the compressor clutch 54 is connected to drive the compressor 52 by the engine 2.

In step S26, in order to stop the drive of the ejector 92, the flow control valve 98 is controlled so that the target ejector side opening becomes zero. In step S27, the expander clutch 35 is disconnected in order to stop the operation of the Rankine cycle 31, and the expander upstream valve 62 is fully closed, and the bypass valve 66 is fully open to bypass the expander 37 for refrigerant Stream all of them.

Proceeding from step S15 to steps S25, S26 and S27 from the next time with the compressor only drive flag = 1 in step S25, the compressor 101 is driven by the motor 101 or the compressor clutch 54 is connected and the compressor 52 is driven by the engine 2 Operate the compressor air conditioner.

Here, the operation and effect of the present embodiment will be described.

According to the present embodiment, the heat exchanger 36 recovers the waste heat of the engine 2 as a refrigerant, the expander 37 generating power using the refrigerant at the outlet of the heat exchanger, and condensing the refrigerant leaving the expander 37 In the waste heat utilization device of an engine provided with a Rankine cycle 31 including a refrigerant pump 32 including a condenser 38, a refrigerant pump 32 which is driven by power regenerated by the expander 37 and supplies the refrigerant from the condenser 38 to the heat exchanger 36. A refrigeration cycle 51 including an evaporator 55 sharing the condenser 38 and guiding and evaporating the refrigerant from the condenser 38, and using the refrigerant at the outlet of the heat exchanger 36 as a driving gas, drawing the refrigerant at the outlet of the evaporator 55 And an ejector 92 for returning to the condenser 38.

According to the present embodiment, the Rankine cycle 31 is operated by driving the refrigerant pump 32 using the power regenerated by the expander 37, and the ejector 92 is a part of the refrigerant circulating in the refrigerant passage of the Rankine cycle 31. To drive the refrigeration cycle 51 (see steps S1 and S7 to S13 in FIG. 16A). Thereby, the refrigeration cycle 51 can be operated only by the heat energy of the waste heat of the engine 2.

Efficiency is improved by changing the ratio of the refrigerant supplied to the expander 37 that drives the refrigerant pump 32 and the refrigerant supplied to the ejector 92 according to the environment (conditions) in which the waste heat utilization device is placed. For example, in the condition where the capacity of the condenser 38 is high (the amount of heat release is large), a high expander torque can be obtained even with a relatively small amount of refrigerant. Under such conditions, the refrigerant supplied to the ejector 92 is relatively increased. Thus, the output (cooling capacity) of the refrigeration cycle 51 can be improved. In this embodiment, the flow control valve 98 can further control the distribution ratio between the flow rate of the refrigerant supplied to the ejector 92 from the outlet of the heat exchanger 36 and the flow rate of the refrigerant supplied to the expander 37 from the outlet of the heat exchanger 36. Since the (flow rate distribution ratio control mechanism) is provided, by controlling the flow rate control valve 98, the refrigerant superheated by the engine waste heat can be arbitrarily distributed to the expander 37 and the ejector 92. Therefore, when circulating and supplying the refrigerant that is also the driving source of the ejector 92 using engine waste heat, the driving force (the amount of refrigerant) of the refrigerant pump 32 and the driving force (the amount of refrigerant) of the ejector 92 are arbitrarily adjusted. The possible configuration can provide a waste heat utilization device with further improved efficiency.

According to the present embodiment, the target ejector supply flow rate (the refrigerant flow rate to the ejector 92 side) is calculated based on the air conditioner set temperature and the condenser capacity (heat release amount of the condenser 38) (step 8 of FIG. 16A, Even if the set temperature of the air conditioner and the condenser capacity (heat release amount of the condenser 38) are different, the target ejector supply flow rate can be given without excess or deficiency.

According to the present embodiment, when the power regenerated by the expander 37 exceeds the driving force of the refrigerant pump 32, the power transmission mechanism (2a, 33 to 35) is provided to transmit the increased power to the engine 2. Then, when there is an air conditioner request (cooling request) during idle stop (during engine stop) (may be when there is an air conditioner request in a low load state), the expander clutch 35 (clutch) is disconnected and regeneration is performed by the expander 37 The Rankine cycle 31 is operated so as not to transmit the motive power to the engine 2, and a part of the refrigerant circulating in the refrigerant passage of the Rankine cycle 31 is supplied to the ejector 92 to drive the ejector 92 and the refrigerant pump 32. The flow rate control valve 98 (flow rate distribution ratio control mechanism) is controlled so that the actual rotation speed of the target rotation speed coincides with the target rotation speed. For example, when the actual rotation speed is lower than the target rotation speed, the target ejector side opening degree is corrected to decrease (the distribution ratio of the refrigerant flow rate to the expander 37 is increased) and the actual rotation speed is higher than the target rotation speed. Because the target ejector side opening degree is increased and corrected (the distribution ratio of the refrigerant flow rate to the ejector 92 is increased) (see steps S18, S19, and S22 in FIG. 16B), the air conditioning capacity during idle stop is extended to a constant capacity. It can be maintained.

According to the present embodiment, the refrigeration cycle 51 is provided with the compressor 52 provided in parallel with the ejector 92, and the driving of the ejector 92 is stopped when the temperature of the evaporator 55 becomes higher than the target temperature. The compressor 52 is driven (see steps S24 and S25 in FIG. 16B). As a result, when there is an air conditioner request (cooling request) during idle stop (even if there is an air conditioner request in a low load state), the target temperature of the evaporator 55 can not be maintained in the operation of the refrigeration cycle 51 by the ejector 92 Also in this case, the target temperature of the evaporator 55 can be maintained so that the cooling capacity is not affected.

Second Embodiment
The flowcharts of FIGS. 22A and 22B are control performed by the engine controller 71 according to the second embodiment, and replace the flowcharts of FIGS. 16A and 16B of the first embodiment. The same steps as those in the flowcharts of FIGS. 16A and 16B are denoted by the same step numbers.

The parts different from FIGS. 16A and 16B of the first embodiment will be mainly described. If it has not been shifted to the compressor drive in step S15 in FIG. 22B, the process proceeds to step S31 and thereafter.

Steps S31 to S35 and S21, and steps S31, S36, S24, S35, and S21 are portions for performing the torque assistless ejector air conditioner operation shown in FIG. Among these, steps S31 to S36 are portions for gradually increasing the target expander side opening degree of the flow control valve 98 from the initial value. Here, not the ejector-side opening of the flow control valve 98 but the expander-side opening of the flow control valve 98 is controlled.

First, in step S31, it is determined whether the basic expander side opening degree of the flow control valve 98 has been calculated. For example, when the basic expander side opening calculated flag = 1, it is determined that the basic expander side opening of the flow control valve 98 has been calculated, and the basic expander side opening calculated flag = 0 At this time, it is determined that the basic expander side opening degree of the flow control valve 98 has not been calculated. If it is determined that the basic expander side opening calculated flag = 0, that is, if the basic expander side opening of the flow control valve 98 has not been calculated, the process proceeds to step S32. In step S32, the basic expander, which is the initial value of the flow control valve 98, is searched by searching the table shown in FIG. 23 from the temperature of the refrigerant exiting from the outlet of the heat exchanger 36 detected by the temperature sensor (not shown). Calculate the side opening. Here, although the expander side opening degree was calculated based on refrigerant | coolant temperature, it can also be calculated based on a refrigerant | coolant pressure.

The expander torque is affected by the temperature of the refrigerant exiting from the outlet of the heat exchanger 36, and when the refrigerant exiting from the outlet of the heat exchanger 36 becomes cold, the expander torque decreases. Therefore, as shown in FIG. 23, the basic expander side opening degree is set to increase as the temperature of the refrigerant exiting from the outlet of the heat exchanger 36 decreases, so that the expander torque does not run short.

Since the basic expander side opening degree is calculated in step S32, the basic expander side opening calculated flag is set to 1 in step S33, and the target expander expansion rate of the flow control valve 98 is set to the initial value in step S34. Put in the machine side opening.

In step S35, the flow control valve 98 is controlled to have the target expander side opening (initial value). In step S21, since the torque assist is not performed and the Rankine cycle 31 is operated, the expander clutch 35 is disconnected, the expander upstream valve 62 is fully opened, and the bypass valve 66 is fully closed. The refrigerant flowing out of the outlet of is flowed to the expander 37. In this case, even if the expander torque drives the refrigerant pump 32 and there is still a surplus, torque assist is not performed, and the amount of refrigerant used for torque assist is reduced and directed to the ejector 92 side. Increase the amount of refrigerant. This makes it possible to improve the effectiveness of the air conditioner (cooling) and prolong the duration.

By setting the basic expander side opening calculated flag = 1 at step S33, the process proceeds from step S31 to step S36 from the next time. In step S36, the target expander side opening degree is updated by the following equation.
Target expander side opening degree = target expander side opening degree + ΔZOU (1)
However, ΔZOU: expansion side opening degree per control cycle (positive value)

The “target expander side opening degree” on the right side of the equation (1) represents a value calculated last time, and the “target expander side opening degree” on the left side of the equation (1) represents a value calculated this time. Since the basic expander side opening degree is set as the initial value to the target expander side opening degree at the previous time, a value obtained by adding the increment ΔZOU to the basic expander side opening degree is calculated as the target expander side opening degree. At the next time, a value obtained by adding the increment ΔZOU × 2 to the basic expander side opening degree is calculated as the target expander side opening degree. Thus, the target expander side opening degree is gradually increased from the initial value.

Here, the reason for gradually increasing the target expander side opening degree from the initial value is as follows. That is, it is at the time of an idle stop state (engine stop state) or a low load state to progress to step S31 or later of FIG. 22B. In particular, considering the case where the process proceeds from step S31 in FIG. 22B at the timing when the operation state of the engine 2 is shifted to the idle stop to stop the engine 2, the engine with the passage of time from the start of the idle stop at which the engine 2 stops. Since the residual heat of 2 is gradually dissipated, the temperature of the refrigerant exiting from the outlet of the heat exchanger 36 decreases. For this reason, if the target expander side opening degree is maintained at the initial value, the expander torque decreases as the refrigerant temperature decreases. When the expander torque decreases, the pump rotational speed decreases, and the flow rate of the refrigerant circulating through the Rankine cycle 31 decreases. Then, the flow rate of the refrigerant supplied to the ejector 92 decreases, the flow rate of the refrigerant circulating through the refrigeration cycle 51 decreases, and the cooling capacity decreases. In order to prevent such a decrease in cooling capacity, it is necessary to maintain the expander rotational speed at the idle stop transition timing even after the start of the idle stop or after shifting to a low load state. Therefore, by gradually increasing the target expander side opening degree from the start of the idle stop, the expander torque at the idle stop transition timing is maintained even after the start of the idle stop.

If the target expander side opening degree is gradually increased, the ejector side opening degree gradually decreases conversely, the driving of the ejector 92 becomes insufficient, and eventually the ejector 92 can not operate the refrigeration cycle 51. When the ejector 92 can not operate the refrigeration cycle 51, the evaporator temperature can not be maintained, and the evaporator temperature starts to rise. In order to observe the temperature rise of the evaporator, the evaporator temperature is compared with a predetermined value in step S24. When the evaporator temperature is equal to or lower than the predetermined value, it is determined that the sufficient cooling capacity is obtained by the drive of the ejector 92 by the refrigerant supply at the current ejector side opening degree. That is, it is determined that it is not necessary to shift to the operation of the refrigeration cycle 51 driven by the compressor 52, and the process proceeds to steps S35 and S21, and the processes of steps S35 and S21 are performed.

The target expander side opening degree gradually increases by repeating the process of step S36 as long as the evaporator temperature is equal to or less than the predetermined value. If the target expander side opening degree of the flow control valve 98 is gradually increased, the ejector side opening degree of the flow control valve 98 gradually decreases. If the ejector side opening degree of the flow control valve 98 becomes smaller gradually, the operation of the ejector 92 becomes worse, and the movement of the refrigerant circulating through the refrigeration cycle 51 becomes dull. As a result, the evaporator temperature eventually rises and reaches a predetermined value. In this case, the process proceeds from step S24 to steps S25 to S27.

Steps S25 to S27 are parts for operating the compressor air conditioner. First, at step S25, the compressor single drive flag is set to 1 and a current is supplied to the motor 101 to drive the compressor 52 or the compressor clutch 54 is connected to drive the compressor 52 by the engine 2.

In step S26, the expander clutch 35 is disconnected in order to stop the operation of the Rankine cycle 31, and the expander upstream valve 62 is fully closed, and the bypass valve 66 is fully open to bypass the expander 37 for refrigerant Stream all of them.

According to the second embodiment, the engine controller 71 (idle stop device) for performing idle stop to stop the engine 2 when a predetermined condition is satisfied during operation of the vehicle 1 is provided. When there is a demand (when there is a demand for an air conditioner in a low load state), the Rankine cycle 31 is operated with the expander clutch 35 (clutch) disconnected. While a part of the refrigerant circulating in the refrigerant passage of the Rankine cycle 31 is supplied to the ejector 92 to drive the ejector 92, the basic expander side opening degree (expansion (expansion) as the temperature of the refrigerant exiting from the outlet of the heat exchanger 36 decreases. The flow control valve 98 (flow distribution ratio control mechanism) is controlled so that the distribution ratio of the refrigerant flow to the device 37 becomes large (see step S32 in FIG. 22B). Under conditions where the amount of waste heat recovery is large, high expander torque can be obtained even with a relatively small amount of refrigerant. Under such conditions, the amount of refrigerant supplied to the ejector 92 is relatively large, so that the output of the refrigeration cycle 51 (cooling Ability) can be improved. According to the present embodiment, while the amount of waste heat recovery is large (the temperature of the refrigerant at the outlet of the heat exchanger 36 is high), the opening degree on the ejector 92 side is increased to obtain a high cooling capacity. When the amount is small (the refrigerant temperature at the outlet of the heat exchanger 36 is low), the expansion unit 37 side is enlarged to secure the expansion unit torque necessary for the operation of the ejector air conditioner, thus making the ejector air conditioner longer Driving can be continued. Further, even if the pump rotational speed can not be detected, the control of the air conditioning capacity during idle stop can be performed by the temperature of the refrigerant exiting from the outlet of the heat exchanger 36, and the rotational speed sensor can be omitted to reduce the cost.

With the passage of time from the start of the idle stop (or low load state), the remaining heat of the engine 2 disappears. According to this tendency, according to the second embodiment, the target expander side opening degree (the distribution ratio of the flow rate of the refrigerant to the expander 37) is increased with the passage of time from the start of the idle stop (FIG. 22B (See steps S31, S32, S34, steps S31 and S36), and as the remaining heat of the engine 2 disappears with the passage of time from the start of the idle stop, the refrigerant coming out of the outlet of the heat exchanger 36 Can be supplied.

Third Embodiment
FIG. 25 is a layout diagram of the radiator 11 and the condenser 38 of the third embodiment. In the relationship with FIG. 10, it corresponds to what took out and showed only the radiator 11 and the condenser 38 from the structure of FIG. Therefore, the remaining configuration is the same as the configuration shown in FIG.

In the first and second embodiments, the condenser 38 is disposed in parallel with the radiator 11, and both are collectively cooled by the radiator fan 12. In the third embodiment, as shown in FIG. 25, the radiator 11 and the condenser 38 are cooled by

independent fans

12 and 105. That is, the radiator 11 is configured to be cooled by only the radiator fan 12, and the condenser 38 is configured to be cooled by the cooling fan 105 dedicated to the condenser 38. When the air conditioner is required during idle stop, the cooling fan 105 is driven.

According to the third embodiment, the cooling fan 105 for blowing air only to the condenser 38 is provided, and when there is an air conditioning request (cooling request) during idle stop, this cooling fan 105 is driven. This makes it possible to cool only the refrigerant without cooling the cooling water, requiring only a small amount of energy, and the residual heat of the engine 2 keeps the air conditioning capacity during idle stop, while the cooling air is supplied only to the condenser 38 It can be extended more than the case without the cooling fan 105 for sending.

Fourth Embodiment
FIG. 26 is a schematic configuration diagram of an integration cycle of the fourth embodiment. In the fourth embodiment, the branch refrigerant passage 97 forming the ejector circuit has a role of a passage that bypasses the expander 37, thereby reducing the expander bypass passage 65 provided in the first embodiment. did. Here, when it is desired to bypass the expander 37, the flow rate control valve 98 increases the refrigerant flow ratio on the ejector 92 side. For example, when the Rankine cycle 31 is activated, the refrigerant flow ratio (opening degree) on the ejector 92 side of the flow control valve 98 is increased, and the expansion device 37 is bypassed to shorten the activation time. Further, when it is not necessary to operate the refrigeration cycle 51 while the Rankine cycle 31 is operating, all refrigerants are made to flow to the expander 37 side.

According to the fourth embodiment, since the branch refrigerant passage 97 (ejector circuit) also serves as a passage for bypassing the expander 37, the expander bypass passage 65 provided in the first embodiment is used. It can be reduced and the system can be simplified.

Fifth Embodiment
The schematic block diagram of the integration cycle of the fifth embodiment is the same as the schematic block diagram of the fourth embodiment shown in FIG. In the previous embodiments, the opening degree of the flow control valve 98 is controlled so as to arbitrarily distribute the flow rate on the expander 37 side and the refrigerant flow rate on the ejector 92 side. In this case, Problems may arise.

For example, when the flow rate of refrigerant on the ejector 92 side is relatively large, the flow rate of refrigerant bypassing the expander 37 (passing through the ejector 92) is increased, and the pressure difference across the expander 37 (between upstream and downstream) The pressure difference between the front and back may be reduced, and the ejector performance may be degraded. Therefore, if the flow path on the side of the ejector 92 is narrowed in order to reduce the flow rate of the refrigerant on the side of the ejector 92, a pressure loss occurs this time to cause an energy loss, and the pressure difference before and after the ejector 92 also decreases. It may cause a drop in ejector performance. As described above, when the ejector 92 is operated under the condition that the efficiency of the ejector 92 is low, energy may be wasted due to the refrigerant pressure difference (the pressure difference between the expander 37 or the ejector 92).

Therefore, in the present embodiment, for example, in the case where the flow rate on the ejector 92 side is reduced under the condition of operating the ejector 92 due to the request of the air conditioner cooler (drive of the refrigeration cycle 51), the refrigerant flow rate on the ejector 92 side is zero. By doing this, energy loss is prevented. When the refrigerant flow rate on the ejector 92 side becomes zero, the pressure difference before and after the expander 37 increases, so the high-pressure side pressure (the outlet pressure of the heat exchanger 36) has a first predetermined value (pressure A in FIG. 29 described later). If it becomes above, a refrigerant | coolant will be flowed to the ejector 92 side (At this time, a throttling is eliminated or it makes a small throttling). When the high-pressure side pressure again becomes equal to or less than a second predetermined value (pressure B in FIG. 29 described later) smaller than the first predetermined value, the refrigerant flow rate on the ejector 92 side is made zero. By repeating such an operation, the pressure difference before and after the ejector 92 always becomes large, and the performance / efficiency improvement at the time of operation of the ejector 92 can be realized.

For the predetermined value of the high-pressure side pressure (the outlet pressure of the heat exchanger 36), the first predetermined direct pressure (pressure A in FIG. 29 described later) is an upper limit pressure for preventing the expander 37 from over-rotation. The second predetermined value (pressure B in FIG. 29 described later) can be set to the lower limit pressure that prevents the expander 37 from obtaining sufficient power regeneration (A> B). The high-pressure side pressure may be measured by providing a pressure sensor (not shown) at the outlet of the heat exchanger 36 (before branching).

In addition, in order to prevent the expander 37 from being overrotated frequently when the refrigerant flow rate on the ejector 92 side is made zero, it is possible to provide a means for narrowing the passage on the expander 37 side. FIGS. 27 and 28 show an example in which the flow path on the ejector 92 side is made zero and the passage on the expander 37 side can be narrowed. In FIG. 27, the on-off valve 106 is provided in the upstream portion of the ejector 92 of the branch refrigerant passage 97, and the opening 37 on the expander 37 side of the flow control valve 98 is adjusted when the on-off valve 106 is closed. It is possible to squeeze the passage of In FIG. 28, similarly to FIG. 27, after providing the on-off valve 106 in the upstream portion of the ejector 92 of the branch refrigerant passage 97, the flow control valve 107 in the upstream portion of the expansion device 37 of the refrigerant passage 42 instead of the flow control valve 98. By adjusting the opening degree of the flow control valve 107 when the on-off valve 106 is closed, the passage on the expander 37 side can be narrowed. In this case, the flow distribution ratio can be controlled by the cooperation of the on-off valve 106 and the flow control valve 107.

FIG. 29 shows the control states of the on-off valve 106 and the flow control valve 107, the high pressure (the outlet pressure of the heat exchanger 36), and the expander 37 (refrigerant pump) when the high pressure is controlled according to the fifth embodiment. 32 is a timing chart showing transition of the rotational speed. When the high-pressure side pressure reaches the upper limit pressure (pressure A which is a first predetermined value) for preventing the expander 37 from over-rotation, the on-off valve 106 is opened and the opening degree of the flow control valve 107 is increased. Do. Also, when the high pressure side pressure reaches the lower limit pressure (pressure B which is a second predetermined value) that prevents sufficient power regeneration from being obtained by the expander 37, the on-off valve 106 is closed and the flow control valve 107 Reduce the degree of opening. By repeating such an operation, the pressure difference before and after the ejector 92 always becomes large, and the performance / efficiency improvement at the time of operation of the ejector 92 can be realized.

As in the case of clutch cycling of the compressor 52, the temperature of the outlet air of the air conditioner evaporator 55 is detected within the range where the expander 37 does not cause excessive rotation, and the temperature falls within a predetermined target temperature range. The operation / non-operation of the ejector 92 may be controlled.

Alternatively, the passage on the expander 37 side is intermittently shut off (stopping the refrigerant supply), for example, every predetermined period to adjust the average refrigerant flow rate per unit time, and without narrowing the path on the expander 37 side. The rotational speed of the expander 37 can also be adjusted. In this way, the energy loss due to the refrigerant pressure loss generated by the throttling (FIGS. 27 and 28) is eliminated, the refrigerant flow rate on the ejector 92 side is increased by that amount, and the performance of the ejector 92 can be improved.

According to the fifth embodiment, when the flow rate on the ejector 92 side is reduced, the refrigerant flow rate on the ejector 92 side is made zero, so generation of energy loss is prevented, and the pressure difference before and after the ejector 92 is always large. As a result, performance / efficiency improvement can be realized when the ejector 92 operates.

Although the above embodiment has been described in the case of a hybrid vehicle, the present invention is not limited to this. The present invention can be applied to a vehicle equipped with only the engine 2. The engine 2 may be either a gasoline engine or a diesel engine.

The present application claims priority based on Japanese Patent Application No. 2011-216756 filed on September 30, 2011, to the Japanese Patent Office, and the entire contents of this application are incorporated herein by reference.

Claims

A heat exchanger which recovers the waste heat of the engine as a refrigerant, an expander which generates power by using the refrigerant at the outlet of the heat exchanger, a condenser which condenses the refrigerant which has exited the expander, which is regenerated by the expander In a waste heat utilization device of an engine provided with a Rankine cycle including a refrigerant pump driven by power and supplying a refrigerant from the condenser to the heat exchanger,
A refrigeration cycle including an evaporator that shares the condenser and leads and evaporates the refrigerant from the condenser;
An ejector that uses the refrigerant at the outlet of the heat exchanger as a drive gas and draws the refrigerant at the outlet of the evaporator back to the condenser;
A waste heat utilization device of an engine provided with a flow distribution ratio control mechanism capable of controlling a distribution ratio between the flow rate of refrigerant supplied to the ejector from the heat exchanger outlet and the flow rate of refrigerant supplied to the expander from the heat exchanger outlet .
In the engine waste heat utilization device according to claim 1,
The waste heat utilization device of the engine which calculates the refrigerant | coolant flow volume to the said ejector side based on the air-conditioner preset temperature and the capability of the said condenser.
In the engine waste heat utilization device according to claim 1 or 2,
It further comprises a power transmission mechanism for transmitting the motive power that has been regenerated by the expander to the engine when the motive power regenerated by the expander exceeds the driving force of the refrigerant pump,
When there is a cooling demand while the engine is stopped, the Rankine cycle is operated so that the power regenerated by the expander is not transmitted to the engine, and a portion of the refrigerant circulating in the refrigerant passage of the Rankine cycle is the ejector And driving the ejector, and controlling the flow distribution ratio control mechanism such that the actual rotational speed of the refrigerant pump matches the target rotational speed.
In the engine waste heat utilization device according to claim 1 or 2,
It further comprises a power transmission mechanism for transmitting the motive power that has been regenerated by the expander to the engine when the motive power regenerated by the expander exceeds the driving force of the refrigerant pump,
When there is a cooling demand in a low load state of the engine, the Rankine cycle is operated so that the power regenerated by the expander is not transmitted to the engine, and a part of the refrigerant circulating in the refrigerant passage of this Rankine cycle is An exhaust heat utilization device for an engine, which supplies the ejector to drive the ejector and controls the flow rate distribution ratio control mechanism so that the actual rotational speed of the refrigerant pump coincides with a target rotational speed.
In the engine waste heat utilization device according to claim 1 or 2,
It further comprises a power transmission mechanism for transmitting the motive power that has been regenerated by the expander to the engine when the motive power regenerated by the expander exceeds the driving force of the refrigerant pump,
When there is a cooling demand while the engine is stopped, the Rankine cycle is operated so that the power regenerated by the expander is not transmitted to the engine, and a portion of the refrigerant circulating in the refrigerant passage of the Rankine cycle is the ejector An engine for controlling the flow rate distribution ratio control mechanism so as to drive the ejector and drive the ejector and to increase the distribution ratio of the refrigerant flow rate to the expander as the refrigerant temperature or the refrigerant pressure at the heat exchanger outlet decreases. Waste heat utilization device.
In the engine waste heat utilization device according to claim 1 or 2,
It further comprises a power transmission mechanism for transmitting the motive power that has been regenerated by the expander to the engine when the motive power regenerated by the expander exceeds the driving force of the refrigerant pump,
When there is a cooling demand in a low load state of the engine, the Rankine cycle is operated so that the power regenerated by the expander is not transmitted to the engine, and a part of the refrigerant circulating in the refrigerant passage of this Rankine cycle is While supplying to the ejector to drive the ejector, the flow distribution ratio control mechanism is controlled such that the distribution ratio of the refrigerant flow to the expander increases as the refrigerant temperature or refrigerant pressure at the heat exchanger outlet decreases. Waste heat utilization equipment for engines.
In the engine waste heat utilization device according to claim 6,
An engine waste heat utilization device for increasing the distribution ratio of the refrigerant flow rate to the expander as time passes from the start of the engine stop or the low load state of the engine.
In the engine waste heat utilization device according to any one of claims 3 to 7,
The cooling device further includes a cooling fan for blowing air to the condenser.
The waste heat utilization device of the engine which drives this cooling fan in the engine stop or the low load state of the engine.
In the engine waste heat utilization device according to claim 8,
The cooling fan is provided separately from a radiator fan provided for engine cooling water, and is a cooling fan that blows air only to the condenser.
The waste heat utilization device for an engine according to any one of claims 3 to 8,
The refrigeration cycle includes a compressor provided in parallel with the ejector,
The waste heat utilization device of the engine which stops the drive of the said ejector and drives the said compressor, when the temperature of the said evaporator becomes higher than target temperature.
The waste heat utilization device for an engine according to any one of claims 1 to 10,
Under the condition for operating the ejector, when the value correlated with the refrigerant pressure at the heat exchanger outlet becomes equal to or more than a first predetermined value, the refrigerant is supplied from the heat exchanger outlet to the ejector to operate the ejector When the value correlated with the refrigerant pressure at the outlet of the expander becomes equal to or less than a second predetermined value smaller than the first predetermined value, the refrigerant supply to the ejector is stopped and the refrigerant is transferred from the heat exchanger outlet to the expander The waste heat utilization device of the engine which repeats supply and stop of the refrigerant to the said ejector by supplying to.
In the engine waste heat utilization device according to claim 11,
The engine waste heat utilization apparatus which adjusts the rotational speed of the said expander by adjusting the opening degree of the control valve provided upstream of the said expander, when stopping the refrigerant | coolant supply to the said ejector.
The engine waste heat utilization device according to any one of claims 1 to 12,
The flow rate distribution ratio control mechanism changes the refrigerant supply amount from the heat exchanger outlet to the expander per predetermined time by intermittently stopping the refrigerant supply to the expander, thereby changing the expander Waste heat utilization device of the engine to adjust the rotation speed of