CN106837598B

CN106837598B - Heat exchanger for waste heat recovery

Info

Publication number: CN106837598B
Application number: CN201610566816.XA
Authority: CN
Inventors: 徐正玟
Original assignee: Hyundai Motor Co
Current assignee: Hyundai Motor Co
Priority date: 2015-12-07
Filing date: 2016-07-18
Publication date: 2022-05-06
Anticipated expiration: 2036-07-18
Also published as: KR20170066876A; DE102016212875A1; CN106837598A

Abstract

Disclosed herein is a heat exchanger for waste heat recovery, comprising: a housing; an inlet cover configured to be installed at one side of the housing and having an inlet hole into which the working medium is introduced; and a defroster configured to be installed inside the inlet cover to separate the lubricating oil from the working medium.

Description

Heat exchanger for waste heat recovery

Cross Reference of Related Applications

This application is based on and claims the benefit of priority of korean patent application No. 10-2015-0173066, filed on 7.12.2015 to the korean intellectual property office, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present disclosure relates to a heat exchanger for waste heat recovery, and more particularly, to a heat exchanger for waste heat recovery having a structure in which a heat exchanger disposed at a downstream side of an expander is integrated with an oil separating structure.

Background

Internal combustion engines have been widely used for vehicles, ships, small-sized generators, and the like, and attempts to improve the efficiency of internal combustion engines have been continuously made. In an internal combustion engine, a large amount of heat is generally discharged as waste heat, and a waste heat recovery system for increasing the overall efficiency of the internal combustion engine by recovering the waste heat as energy has been developed.

The exhaust heat recovery system is configured to recover exhaust heat discharged from the engine as energy and convert the recovered energy into electric energy or mechanical energy, and utilize the electric energy or mechanical energy in the engine, other accessories, and the like of the vehicle.

The waste heat recovery system includes a Rankine cycle (Rankine cycle) for recovering waste heat of the engine very efficiently. The rankine cycle includes a circulation path through which a working medium circulates, wherein the circulation path of the rankine cycle includes a boiler (evaporator) configured to heat and evaporate the working medium by waste heat of an engine (heat of exhaust gas and/or heat of EGR gas), an expander configured to expand the gaseous working medium supplied from the boiler to generate rotational energy, a condenser configured to condense the working medium discharged from the expander, and a pump configured to circulate the working medium on the circulation path.

The expander is the most important component in the overall performance and durability of the waste heat recovery system. The expander is directly exposed to the high temperature and high pressure working medium and continuously rotates within the system and therefore may have the highest risk of damage.

In addition, the expander needs to be supplied with lubricating oil to prevent wear and damage of rotating parts (such as high-speed rotating bearings). In this case, however, some of the lubricating oil may be introduced into each component of the waste heat recovery system while being mixed with the working medium. In particular, if the lubricating oil is introduced into a heat exchanger, such as a recuperator and a condenser, which are adjacently installed at the outlet of the expander, an oil film is generated, and thus heat transfer efficiency may be reduced.

Therefore, an oil separator is installed on the downstream side of the expander to separate oil from the working medium discharged from the outlet of the expander.

As described above, the existing waste heat recovery system has a problem in that, because the oil separator is installed between the outlet of the expander and the heat exchanger, the moving path of the working medium is complicated and thus the efficiency of the expander may be reduced.

Furthermore, the flow rate of the working medium passing through the oil separator needs to be maintained at about 1m/s or less to easily separate the oil within the working medium. Therefore, in order to maintain a low flow rate of the working medium, the size of the oil separator needs to be excessively large, and thus the oil separator may occupy a very large installation space in the vehicle.

Disclosure of Invention

The present disclosure has been made to solve the above-mentioned problems occurring in the prior art, while fully retaining the advantages achieved by the prior art.

An aspect of the present disclosure provides a heat exchanger for waste heat recovery capable of simplifying a moving path of a working medium by integrating a heat exchanger disposed at a downstream side of an expander with an oil separating structure, thereby improving efficiency of the expander.

According to an exemplary embodiment of the present disclosure, a heat exchanger for waste heat recovery disposed at a downstream side in a waste heat recovery system includes: a housing; an inlet cover configured to be installed at one side of the housing and having an inlet hole into which the working medium is introduced; and a defroster configured to be installed inside the inlet cover to separate the lubricating oil from the working medium.

The inside of the inlet cover may be provided with an extension space extending to be larger than the diameter of the inlet hole.

The defroster may be provided in an extended space of the inlet cover.

The defroster may be installed at a portion having the largest sectional area in the extension space.

The defroster may be constructed of at least one of a mesh pad and a blade group.

The lower portion of the defroster may be provided with a collection groove for collecting the lubricating oil separated from the working medium.

The protrusion may be formed at a side of the collecting groove adjacent to the housing to protrude upward.

According to another exemplary embodiment of the present disclosure, a heat exchanger for waste heat recovery disposed at a downstream side of an expander in a waste heat recovery system includes: a housing; an inlet cover configured to be mounted at one side of the housing; a defroster configured to be installed inside the inlet cover to separate the lubricating oil from the working medium; and a discharge device configured to discharge the lubrication oil separated by the defroster to the outside.

The drain device may include a collection groove configured to collect the lubricating oil separated by the defroster, and a drain port through which the collection groove communicates with the outside.

The discharge port may be opened and closed by a check valve.

The discharge port may have a diameter portion having a sectional area gradually decreasing toward the outside.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

FIG. 1 is a diagram showing one configuration of a general waste heat recovery system;

fig. 2 is a perspective view illustrating a heat exchanger for waste heat recovery according to an exemplary embodiment of the present disclosure;

FIG. 3 is a plan cross-sectional view of the heat exchanger for waste heat recovery of FIG. 2;

FIG. 4 is a cross-sectional view taken along line A-A in FIG. 3;

FIG. 5 is a cross-sectional view taken along line B-B in FIG. 3;

fig. 6 is an enlarged view of a discharge port of a heat exchanger for waste heat recovery according to an exemplary embodiment of the present disclosure, and illustrates a state in which the discharge port is opened by a check valve (check valve); and is

Fig. 7 is a diagram illustrating a state in which a discharge port of a heat exchanger for waste heat recovery is closed by a check valve according to an exemplary embodiment of the present disclosure.

Detailed Description

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. For reference, the sizes of components, the thicknesses of lines, and the like, illustrated in the drawings, to which reference is made in describing exemplary embodiments of the present disclosure, may be slightly enlarged for the purpose of understanding. In addition, terms used to describe the present disclosure are defined in consideration of functions in the present disclosure and thus may be changed according to user and operator intentions, practices, and the like. Therefore, the definitions of the terms should be construed based on the contents throughout the specification.

Fig. 1 is a diagram showing one configuration of a general exhaust heat recovery system.

Referring to fig. 1, the waste heat recovery system 10 includes a circulation path 11 through which a working medium circulates, wherein the circulation path 11 may include a boiler 13 configured to heat and evaporate the working medium by waste heat from an engine (heat from exhaust gas and/or heat from EGR gas), an expander 14 configured to expand the gaseous working medium supplied from the boiler 13 to generate rotational energy, a condenser 12 configured to condense the working medium discharged from the expander 14, and a circulation pump 16 configured to circulate the working medium on the circulation path 11.

Further, a storage tank 15 storing the liquefied working medium from the condenser 12 may be installed between the condenser 12 and the circulation pump 16, and a state in which the storage tank 15 stores the liquefied working medium supplied from the condenser 12 may be maintained, so that the working medium may be more smoothly circulated.

A boiler 13 may be installed at one side of the exhaust pipe to exchange heat between the working medium and the exhaust gas.

Further, a superheater 17 that heats the working medium by the EGR gas may be installed between the boiler 13 and the expander 14.

Further, a recuperator (regenerator) 18 is installed on a downstream side of the circulation pump 16 and may be configured to exchange heat between the working medium discharged from the condenser 12 and the working medium collected to the condenser 12. The working medium to be heated by the boiler 13 next can be appropriately preheated by the recuperator 18, and thus the evaporation efficiency of the boiler 13 can be improved, and the working medium to be collected to the condenser 12 next can be cooled in advance, and thus the condensation efficiency of the condenser 12 can be improved.

Fig. 2 is a perspective view illustrating one form of a heat exchanger for waste heat recovery according to an exemplary embodiment of the present disclosure. The heat exchanger 100 for waste heat recovery according to an exemplary embodiment of the present disclosure is a heat exchanger disposed at a downstream side of the expander 14, and the heat exchanger may be at least one of the recuperator 18 and the condenser 12.

The heat exchanger 100 for waste heat recovery according to an exemplary embodiment of the present disclosure may include a housing 110 in which a heat exchange core is accommodated, an inlet cover 120 disposed at one side of the housing 110, and a defroster (defroster) 150 installed inside the inlet cover 120.

The inlet cover 120 may be provided with a portion corresponding to the inlet of the case 110.

The inlet cover 120 may be provided with an inlet hole 121 into which a working medium is introduced and have an extension space 122 formed therein, wherein the extension space 122 may be formed to be larger than the diameter of the inlet hole 121.

The defroster 150 is disposed in the extension space 122 of the inlet cover 120, and particularly, the defroster 150 may be installed at a portion having the largest sectional area in the extension space 122. Accordingly, the defroster 150 may be disposed adjacent to the inlet cover 120 of the housing 110.

Specifically, the defroster 150 may be installed to entirely cover a section of the working medium introduction housing 110 such that the lubrication oil within the working medium may be separated by the defroster 150 before the working medium is introduced into the housing 110.

Further, the defroster 150 may be configured to include a mesh pad (mesh pad), a vane pack (vane pack), and the like.

With this configuration, if the working medium discharged from the outlet of the expander 14 is introduced into the inlet hole 121 of the inlet cover 120 of the heat exchanger 100 for waste heat recovery, the working medium is dispersed while passing through the extension space 122 extending to be larger than the inlet hole 121, and thus the flow rate of the working medium can be reduced. If the working medium having a reduced flow rate passes through the defroster 150, the lubrication oil in the working medium may be collected in the defroster 150 to separate the lubrication oil, and the lubrication oil collected in the defroster 150 may flow down to the lower portion of the defroster 150 by gravity.

The lower portion of the defroster 150 may be provided with a collection groove 130, and the collection groove 130 may be formed at the lower surface of the end of the inlet cover 120, in which the lubricating oil separated by the defroster 150 is collected.

Meanwhile, the lubricating oil flowing down to the lower portion of the defroster 150 may flow obliquely downward toward the case 110 due to the flow of the working medium in the horizontal direction, and may also splash or overflow toward the case 110 when the lubricating oil flows obliquely downward toward the heat exchanger 100.

In order to prevent the lubricating oil from splashing, overflowing, etc., a protrusion 135 protruding upward may be formed at a side of the collecting groove 130 adjacent to the housing 110. The bump 135 can prevent the lubricating oil from splashing or overflowing toward the housing 110.

As shown in fig. 4, the collection groove 130 may be extended lengthwise (length) from a lower surface of an end of the inlet cover 120, and one side of the inlet cover 120 may be provided with a discharge port 140 through which the collection groove 130 communicates with the outside. Specifically, the discharge port 140 may be formed at one end portion of the collection groove 130 to communicate with the outside.

As shown in fig. 6 and 7, the discharge port 140 may be configured to be opened and closed by a check valve 145, wherein the check valve 145 may necessarily prevent the lubrication oil from flowing back toward the collection groove 130. The check valve 145 may have a valve ball and a spring biasing the valve ball.

Further, the discharge port 140 may have a diameter portion 141 formed therein, wherein the diameter portion 141 may be formed to have a sectional area gradually decreasing toward the outside. The operability of the check valve 145 can be ensured by the diameter portion 141.

Describing this in detail, if the amount of collected oil increases, as shown in fig. 6, the pressure P1 of the oil may overcome the spring force of the spring of the check valve 145, so that the check valve 145 may open the discharge port 140 to discharge the lubrication oil.

After the oil is discharged as described above, if the sectional area a1 → a2 to which the oil applies the pressure P1 is gradually reduced, as shown in fig. 7, the pressure P2 of the oil is smaller than the spring force of the spring of the check valve 145, so that the check valve 145 can close the discharge port 140, thereby inevitably preventing the backflow of the lubricating oil and preventing the introduction of foreign substances and the like from the outside.

According to an exemplary embodiment of the present disclosure, an oil separating structure may be integrated at an inlet of a heat exchanger disposed at a downstream side of an expander to simplify a moving path of a working medium, thereby improving efficiency of the expander.

Furthermore, according to an exemplary embodiment of the present disclosure, an oil separating structure may be integrated at an inlet of a heat exchanger to greatly simplify the overall arrangement of a waste heat recovery system, thus saving manufacturing costs.

In the foregoing, although the present disclosure has been described with reference to the exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto, and various modifications and changes may be made by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure claimed in the appended claims.

Symbols of the various elements of the drawings

100: heat exchanger

110: shell body

120: inlet cover

121: inlet aperture

122: extension space

130: collecting groove

140: discharge port

141: diameter part

145: check valve

150: demister

Claims

1. A heat exchanger for waste heat recovery, comprising:

a housing;

an inlet cover provided at one side of the housing and having an inlet hole into which a working medium is introduced; and

a defroster installed inside the inlet cover to separate the lubricating oil from the working medium,

wherein a lower portion of the defroster is provided with a collection groove for collecting the lubricating oil separated from the working medium by the defroster,

wherein a protrusion is formed at a side of the collecting groove adjacent to the housing to protrude upward,

wherein the inlet cover is provided at an inside thereof with an extension space extending to be larger than a diameter of the inlet hole, wherein the defroster is provided in the extension space of the inlet cover, wherein the defroster is installed at a portion of the extension space having a maximum sectional area,

wherein the inlet cover and the housing are separate parts, the working medium flows in a horizontal direction and flows first through the inlet cover and then through the housing, and the defroster is disposed perpendicular to a flow direction of the working medium.

2. The heat exchanger of claim 1, wherein the defroster is constructed of at least one of a mesh pad and a set of blades.

3. A heat exchanger for waste heat recovery, provided on a downstream side of an expander in a waste heat recovery system, comprising:

a housing;

an inlet cover installed at one side of the case;

a defroster installed inside the inlet cover to separate lubricating oil from a working medium; and

a discharge device configured to discharge the lubrication oil separated by the defroster to the outside,

wherein an inside of the inlet cover is provided with an extension space extending to be larger than a diameter of an inlet hole of the inlet cover, wherein the defroster is provided within the extension space of the inlet cover, wherein the defroster is installed at a portion of the extension space having a largest sectional area,

4. The heat exchanger of claim 3, wherein the discharge means includes a discharge port through which the collecting groove communicates with the outside.

5. The heat exchanger of claim 4, wherein the discharge port is opened and closed by a check valve.

6. The heat exchanger of claim 5, wherein the discharge port has a diameter portion having a cross-sectional area that gradually decreases toward the outside.