waste heat recovery unit

Abstract

Waste heat recovery system, including: an engine (1) comprising at least one oil pan (2); an exhaust pipe (51, 52) through which exhaust gas flows which is emitted by the engine (1); a catalyst (6), part or all of which is provided upstream of the engine (1) in a vehicle to clean the exhaust gas; and a waste heat recovery device (7) comprising a heat exchange medium and exchanging heat between the heat exchange medium and the exhaust gas, wherein the waste heat recovery device (7) is provided intermediately in the exhaust pipe (52) downstream of the catalyst (6), and part of the waste heat recovery device (7) is provided at least under a base area (2a) of the oil pan (2), wherein part of the waste heat recovery device (7) is provided between a lower surface of at least the base area (2a) of the oil pan (2) and a plane comprising a lower end position of a suspension frame (8), wherein the waste heat recovery device (7) is provided with an inlet pipe (74) and an outlet pipe (75) for the heat exchange medium, and both the inlet pipe (74) and the outlet pipe (75) are provided above a plane that includes the lower end position of the suspension frame (8), and wherein the output pipe (75) is connected to a wastewater pipe (76) which is positioned between a radiator (4) of the motor (1) and a water pump (11) by means of a pipe body.

Description

[Technical field]

[0001] The present invention relates to a waste heat recovery apparatus that transfers heat in an exhaust gas of a vehicle to an engine heat exchange medium. [State of the art]

[0002] Document JP 2016-121557 A discloses a structure in which a waste heat recovery device is positioned in a floor tunnel.

[0003] Document DE 10 2015 204 352 A1 discloses an internal combustion engine with an exhaust system and a heat collection housing. [Summary of the invention][Problem to be solved by the invention]

[0004] However, since the exhaust heat recovery device described in JP 2016-121557 A is positioned in the floor tunnel, an exhaust duct in a vehicle with a front engine becomes long and a temperature of the exhaust gas flowing into the exhaust heat recovery device decreases and thus the amount of heat recovery decreases, and the reduction of a warm-up time tends to be insufficient. Furthermore, as a channel of the heat exchange medium becomes long, the weight of the heat exchange medium increases, the temperature rise of the cooling water is likely to be delayed, and the reduction of the warm-up time tends to be insufficient. Furthermore, since the heat radiation area of ​​a cooling water channel is large, the amount of heat recovered by the cooling water is more likely to be emitted into the atmosphere before being used for warming up, and the reduction in warming up time tends to be insufficient. Furthermore, since the waste heat recovery device is positioned in the floor tunnel, the cabin space is reduced.

[0005] The present invention has been completed to solve the problems described above, and it is an object of the present invention to provide a waste heat recovery apparatus capable of increasing cabin space while reducing warm-up time. [Means of solving the problem]

[0006] The present invention is defined in independent claim 1. The dependent claims define embodiments of the invention. Disclosed is a waste heat recovery apparatus provided with an engine including at least an oil pan, an exhaust pipe through which exhaust gas discharged from the engine flows, a catalyst, a part or all of which is provided upstream of the engine in a vehicle to purify the exhaust gas, and a waste heat recovery device including a heat exchange medium and exchanging heat between the heat exchange medium and the exhaust gas, in which the waste heat recovery device is interposed in the exhaust pipe downstream of the catalyst, and a part of the waste heat recovery device is provided at least below a base portion of the oil pan. [Advantageous effect of the invention]

[0007] As the exhaust gas temperature increases, the storage amount of the heat exchange medium decreases, and the heat radiation area of ​​the heat exchange medium channel decreases, it is possible to reduce the warm-up time and further increase the cabin space. [Brief description of the drawings] [ Fig. 1] Fig. 1 is a perspective view of a bottom part of an engine of a vehicle, seen obliquely from below. [ Fig. 2] Fig. 2 is a perspective view of a waste heat recovery device and a radiator, seen from the front of the vehicle. [ Fig. 3] Fig. Figure 3 is a conceptual diagram of the waste heat recovery device, viewed from the right side of the vehicle. [ Fig. 4] Fig. Figure 4 is a conceptual diagram of the waste heat recovery apparatus, viewed from the side surface of the engine. [ Fig. 5] Fig. 5 is a bottom view of the waste heat recovery device, viewed from the side of the undersurface of the engine. [ Fig. 6] Fig. 6 is a conceptual diagram of the waste heat recovery device, viewed from the front of the vehicle. [ Fig. 7] Fig. 7 is an enlarged plan view of the waste heat recovery device, viewed from the upper surface. [ Fig. 8] Fig. 8 is a conceptual cross-sectional view of the waste heat recovery device, viewed from the side surface. [ Fig. 9] Fig. 9A is a conceptual cross-sectional view along a line AA in Fig. 8, Fig. 9B is a modification of Fig. 9A, and Fig. 9C is another modification of Fig. 9A. [ Fig. 10] Fig. 10 is a block diagram illustrating the engine equipped with the waste heat recovery device and a flow of a heat exchange medium. [Mode for carrying out the invention]

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings shown in Fig. 1 to Fig. 10 are shown. Fig. 1 to Fig. 6 show an engine and a waste heat recovery apparatus provided around the engine. Fig. 1 illustrates the bottom of the engine 1 viewed from a side surface, and an oil pan 2 is provided at the bottom. Reference numeral 3 denotes a flywheel provided on the side surface of the engine 1. A radiator 4 that sends a heat exchange medium to the engine 1 is provided in front of the engine 1, an exhaust pipe 51 to which exhaust gas from the engine 1 is sent is provided behind the radiator 4, and a casing 6 containing a catalyst is provided interposed in the exhaust pipe 51. A tubular waste heat recovery device 7 is provided downstream of the catalyst casing 6 from the front to the rear of the vehicle, an exhaust pipe 52 is connected downstream of the waste heat recovery device 7, and a muffler (not shown) is connected further downstream of the exhaust pipe 52.The exhaust pipe 52 is positioned to extend over a suspension frame 8 and is formed to be bent in an inverted U-shape over the suspension frame 8.

[0009] The suspension frame 8 is positioned behind the engine 1 and left and right tires are provided on both the left and right sides of the suspension frame 8 via suspension devices (not shown). The exhaust heat recovery device 7 is positioned near the bottom of the oil pan 2 so as to extend below a base portion 2a of the oil pan 2 in the longitudinal direction of the vehicle body, and is positioned to efficiently radiate heat of the exhaust gas to the oil pan 2. One of the left and right sides at the bottom of the oil pan 2 is formed in a concave portion 2b, and the exhaust heat recovery device 7 is positioned so as to extend through the position of the concave portion 2b. The exhaust heat recovery device 7 is positioned above a plane including the lower end position of the suspension frame 8, that is, at a position above a horizontal plane H, which is an extension of the bottom of the suspension frame 8 (see Fig. 4).

[0010] The waste heat recovery device 7 is constructed from an outer cylinder 7a made of a tubular body 70 of the recovery device, and an inner cylinder 7b positioned inside and concentric with the outer cylinder 7a, as shown in Fig. 8. The body 70 of the recovery device is positioned in a side view substantially horizontally in the longitudinal direction of the vehicle body, with a part thereof on the side of the catalyst housing 6, which tilts obliquely upwards. As shown in Fig. 7, the body 70 of the recovery device is positioned so that in a plan view a part thereof is on the side of the suspension frame 8 opposite a diagonally left side. The waste heat recovery device 7 is composed of an exhaust duct 71 formed inside the outer cylinder 7a and a heat exchange medium (coolant) passage 72 having a certain length formed with the inner cylinder 7b positioned concentrically with the outer cylinder 7a, as shown in Fig. 9A. Heat transfer fins 73 are provided radially on a circumferential surface of the inner cylinder 7b between the outer cylinder 7a and the inner cylinder 7b. The heat transfer fins 73 are provided over a certain length L in the axial direction between the exhaust duct 71 and the heat exchange medium passage 72. An input pipe 74 into which the heat exchange medium is introduced and an output pipe 75 from which the heat exchange medium is discharged are connected to the front and rear surfaces of the heat exchange medium passage 72. The input pipe 74 and the output pipe 75 penetrate the side surface of the recovery device body 70 and are led out. The input pipe 74 is provided downstream of the recovery device body 70, and the output pipe 75 is provided upstream of the recovery device body 70. The input pipe 74 is to connect the waste heat recovery device 7 and a heater core, which will be described later, and the output pipe 75 is to connect the waste heat recovery device 7 and a water inlet pipe or a radiator outlet pipe, which will be described later. Furthermore, as in Fig. As shown in Figure 7, the discharge pipe 75 is preferably provided on a generator side (right side of the vehicle) with respect to a center line of the waste heat recovery device 7 in a plan view of the vehicle. This makes it possible to shorten the distance from the discharge pipe 75 and the radiator 4 to a drain pipe 76, thereby further shortening the path of the cooling water reciprocating between the engine 1 and the waste heat recovery device 7. It does not matter which of the input pipe 74 or the output pipe 75 is positioned at the front of the vehicle in the longitudinal direction of the vehicle. Note that, with respect to the exhaust duct 71 and the heat exchange medium passage 72, the inner cylinder 7b, which is the heat exchange medium passage 72, may be positioned at an eccentric position of the outer cylinder 7a, which is the body 70 of the recovery device, as shown in FIG. Fig. 9B. Furthermore, a polygonal shaped passage 722 of the heat exchange medium may be used, as shown in Fig. 9C shown.

[0011] As in Fig. 8, the waste heat recovery device 7 is configured such that a flow X of the exhaust gas of the exhaust passage 71 of the recovery device body 70 is opposite to a flow Y of the heat exchange medium of the heat exchange medium passage 72 to enable the heat transfer fins 73 to efficiently cool the exhaust gas.

[0012] Fig. 10 illustrates a flow of the heat exchange medium that cools the engine 1. The heat exchange medium heated by cooling the engine 1 is sent to a heater (heater core) 10 to heat the heater 10 and is supplied to the exhaust heat recovery device 7. The heat exchange medium heated with the exhaust gas from the exhaust heat recovery device 7 combines with the heat exchange medium cooled by the radiator 4 and is supplied to the engine by a water pump 11. The exhaust heat recovery device 7 is connected to the water pump 11 via the drain pipe (radiator outlet pipe 41 or water inlet pipe 42) 76, which is connected to the discharge pipe 75. The heat exchange medium from the engine 1 is also sent to a thermal valve 12, supplied to a radiator 13 of a CVT (continuously variable transmission), and then supplied to the engine 1 via the water pump 11.

[0013] According to the above-described embodiment, the temperature of the exhaust gas in the exhaust pipe below the base portion of the oil pan 2 near the catalyst housing 6 containing the catalyst is approximately 150 to 200°C higher than the temperature of the exhaust gas in the exhaust pipe below the floor tunnel. Therefore, positioning the waste heat recovery device 7 below the base portion of the oil pan 2 rather than below the floor tunnel achieves a larger temperature difference from the heat exchange medium and provides a greater amount of waste heat recovery. Furthermore, positioning the waste heat recovery device 7 above the plane including the lower end position of the suspension frame 8, that is, the horizontal plane that is an extension of the bottom surface of the suspension frame 8, makes it possible to bring the waste heat recovery device 7 closer to the oil pan 2 and increase the amount of heat radiation from the exhaust gas to the oil pan.This makes it possible to increase the amount of heat recovered by the heat exchange medium and shorten the warm-up time.

[0014] According to the above-described embodiment, the waste heat recovery device 7 is positioned below the base portion of the oil pan 2 near the engine 1, thus shortening the heat exchange medium passage 72 between the engine 1 and the waste heat recovery device 7. Therefore, it is possible to reduce the volume of the heat exchange medium contained therein. It is therefore possible to reduce the delay in the temperature rise of the heat exchange medium, make the heat exchange medium easily heatable, shorten the warm-up time, and also reduce the weight. Furthermore, it is possible to reduce the heat radiation area from the heat exchange medium channel 72, reduce the heat dissipation amount, and thereby prevent the amount of heat recovered by the heat exchange medium from being emitted into the atmosphere before being used for warm-up. This makes it possible to shorten the warm-up time, reduce the load on the water pump 11, and prevent performance deterioration of the engine 1.

[0015] Positioning the waste heat recovery device 7 under the floor tunnel reduces the cabin space, but since the present invention does not position the waste heat recovery device 7 under the floor tunnel, it does not reduce the cabin space. This makes it possible to increase the cabin space and improve passenger comfort. Furthermore, the degree of design freedom of the floor tunnel and the periphery is improved. Since the waste heat recovery device 7 is positioned above the horizontal plane H, which includes the lower end position of the suspension frame 8, it is possible to prevent the suspension frame 8 near the waste heat recovery device 7 from first touching the ground, thereby causing the waste heat recovery device 7 to touch the ground, even in the event of an emergency. This makes it possible to prevent damage to the waste heat recovery device 7.

[0016] Since the waste heat recovery device 7 is provided with the heat exchange medium input pipe 74 and the output pipe 75, and both the input pipe 74 and the output pipe 75 are provided above the plane including the lower end position of the suspension frame 8, it is possible to prevent the suspension frame 8 from first touching the ground, thereby causing the input pipe 74 and the output pipe 75 provided in the waste heat recovery device 7 to touch the ground. This makes it possible to prevent damage to the waste heat recovery device 7.

[0017] Since the discharge pipe 75 is connected to the drain pipe 76 positioned between the radiator 4 and the water pump 11 of the engine 1 via a pipe body (not shown), the heat exchange medium (cooling water) from the discharge pipe 75 does not pass through the radiator 4 during the warm-up process, and thus the heat exchange medium is not cooled by the radiator 4. Furthermore, since the distance between the discharge pipe 75 and the water pump 11 is small, the heat exchange medium (cooling water) can reach the water pump 11 directly while maintaining the recovered heat amount. This makes it possible to shorten the warm-up time.

[0018] Since the pipe body is positioned between the drain pipe 76 and the catalyst housing 6, if the pipe body is not positioned between the drain pipe 76 and the catalyst housing 6, the drain pipe 76 can hardly receive radiant heat from the catalyst, and thus the temperature of the cooling water passing through the drain pipe 76 hardly rises. Therefore, if no such pipe body is positioned between the drain pipe 76 and the catalyst housing 6 after the warm-up is completed, waste water from the radiator 4 can prevent a temperature rise by the catalyst. Therefore, it is possible to reduce the volume of the radiator 4 and sufficiently protect the engine 1.

[0019] Since the waste water of the heater (heater core) 10 is input into the input pipe 74, it is possible to reduce the amount of heat recovered to the cooling water, unlike a case where the cooling water is not cooled by the heater (heater core) 10. Therefore, the heat shielding performance (non-heat recovery performance required after the warm-up process is completed) is improved.

[0020] The waste heat recovery device 7 is connected between the input pipe 74 and the output pipe 75, is provided with the first channel 72A as the passage 72 of the heat exchange medium provided in the inner cylinder 7b through which the heat exchange medium flows, and the second channel 71A as the exhaust gas channel 71 provided between the inner cylinder 7b and the outer cylinder 7a of the waste heat recovery device 7, and at least the side of the oil pan 2 is provided near the second channel 71A, and thus the following effects can be obtained. Since the conventional waste heat recovery device, as described in JP 2016-121557 A, has a structure in which the cooling water passage is positioned on the outer peripheral side of the heat exchange unit, radiant heat from the temperature of the cooling water at about 90°C is transferred to the oil pan 2. The structure of the waste heat recovery device 7 is a structure in which the exhaust gas passage 71 on the outer cylinder 7a side, which is the second passage 71A, is positioned on the outer peripheral side of the cooling water passage 72 as the heat exchange unit, which is the first passage 72A, and thus radiant heat from the temperature of a high-temperature exhaust gas at about 300 to 500°C is transferred to the oil pan 2. Therefore, positioning the waste heat recovery device 7 under the oil pan base 2a rather than under the floor tunnel enables higher temperature heat to be recovered to the engine oil. This makes it possible to increase the amount of heat that is recovered to the engine oil.

[0021] The exhaust pipe 52 is provided with a bent portion 5a bent from below the oil pan base portion 2a toward above the drive shaft, and the vehicle rear end of the first duct 72 is closer to the vehicle front than the bent portion, and thus the following effects are provided. The interior of the exhaust pipe below the oil pan base portion 2a has a shape such that condensed water tends to accumulate. Here, when the first channel 72A on the inner cylinder 7b side serves as the cooling water heat exchange medium channel, and the second channel 71A on the outer cylinder 7a side serves as the exhaust channel 71, heat exchange between the first channel 72A and the second channel 71A is not affected by condensed water or ice, which is solidified condensed water. Therefore, highly efficient heat exchange can be maintained.

[0022] Since the vehicle rear end of the first duct 72A is located closer to the front of the vehicle than the vehicle front end of an engine torsion bar of the engine, it is possible to prevent the problem of thermal deformation of the engine torsion bar. [Industrial applicability]

[0023] In the above-described embodiment, cooling water is used as the heat exchange medium, but any liquid other than water, or a gas, may also be used. The above-described embodiment is not limited to a gasoline engine, but is also applicable to a diesel engine. The input pipe 74 is preferably located on the transmission side (left side of the vehicle) with respect to the center line of the waste heat recovery device 7 in a plan view of the vehicle, as shown in Fig. 7 shown. Since the distance between the input pipe 74 and the heater core 10 can be reduced, the path of the cooling water moving back and forth between the engine 1 and the waste heat recovery device 7 can be shortened. The discharge pipe 75 is preferably arranged on the generator side (right side of the vehicle) with respect to the center line of the waste heat recovery device 7 in a plan view of the vehicle, as shown in Fig. 7 shown. Since the distance between the discharge pipe 75 and the waste pipe 76 of the radiator 4 can be reduced, the path of the cooling water moving back and forth between the engine 1 and the waste heat recovery device 7 can be further shortened. It doesn't matter which of the input pipe 74 or the output pipe 75 is positioned at the front of the vehicle in the longitudinal direction of the vehicle. Note that the output pipe 75 is positioned at the front of the vehicle, which is preferable because it makes it possible to further shorten the path of the cooling water moving back and forth between the engine 1 and the waste heat recovery device 7. Furthermore, a thermoelectric element may be provided. More electricity can be generated using waste heat via the thermoelectric element. Note that the thermoelectric element can be either the waste heat recovery device 7, which is a heat transfer unit, or the oil pan 2, which is a heat receiving unit. In addition, the invention can, of course, be implemented by making appropriate modifications within the scope of the present invention. [List of reference symbols] 1 engine 2 oil pan 3 flywheel 4 Radiators 41 Radiator outlet pipe 42 Water inlet pipe 51, 52 exhaust pipe 6 Catalytic converter housing 7 Waste heat recovery device 7a outer cylinder 7b inner cylinder 8 hanging frames 10 Heating 11 Water pump 70 Body of the recovery device 71 exhaust duct 71A second channel 72, 722 Passage of the heat exchange medium 72A first channel 73 heat transfer fins 74 Input pipe 75 Discharge tube 76 sewer pipe

Claims

[1] Waste heat recovery apparatus comprising: an engine (1) comprising at least one oil pan (2); an exhaust pipe (51, 52) through which an exhaust gas discharged from the engine (1) flows; a catalyst (6), part or all of which is provided in front of the engine (1) in a vehicle to purify the exhaust gas; and a waste heat recovery device (7) comprising a heat exchange medium and exchanging heat between the heat exchange medium and the exhaust gas, wherein the waste heat recovery device (7) is provided intermediately in the exhaust pipe (52) downstream of the catalyst (6), and a part of the waste heat recovery device (7) is provided at least under a base portion (2a) of the oil pan (2), wherein a part of the waste heat recovery device (7) is provided between a lower surface of at least the base portion (2a) of the oil pan (2) and a plane comprising a lower end position of a suspension frame (8), wherein the waste heat recovery device (7) is provided with an input pipe (74) and an output pipe (75) of the heat exchange medium, and both the input pipe (74) and the output pipe (75) are provided above a plane which includes the lower end position of the suspension frame (8), and wherein the discharge pipe (75) is connected to a waste pipe (76) positioned between a radiator (4) of the engine (1) and a water pump (11) by means of a pipe body. [2] A waste heat recovery apparatus according to claim 1, wherein the pipe body is positioned between the waste pipe (76) and the catalyst (6). [3] A waste heat recovery apparatus according to claim 1 or 2, wherein waste water of a heater core is introduced into the input pipe (74). [4] A waste heat recovery apparatus according to any one of claims 1 to 3, wherein the waste heat recovery device (7) comprises a first passage (72A) through which the heat exchange medium flows, and a second passage (71A) provided at a peripheral portion of the first passage (72A) through which the exhaust gas flows, and the second passage (71A) is positioned between the first passage (72A) and the oil pan (2). [5] A waste heat recovery apparatus according to claim 4, wherein the exhaust pipe (52) includes a bent portion (5a) bent from below the base portion (2a) of the oil pan (2) toward above a drive shaft, and a vehicle rear end of the first duct (72A) is located closer to the front of the vehicle than the bent portion (5a). [6] A waste heat recovery apparatus according to claim 4 or 5, wherein the vehicle rear end of the first duct (72A) is located closer to the front of the vehicle than the front end of the vehicle of an engine torsion bar of the engine (1).

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