EP2063097A1

EP2063097A1 - Internal combustion engine having exhaust gas cooling in cooling jacket

Info

Publication number: EP2063097A1
Application number: EP07121246A
Authority: EP
Inventors: Martin Wayne Dirker
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2007-11-21
Filing date: 2007-11-21
Publication date: 2009-05-27

Abstract

An internal combustion engine (12) is disclosed that may include a cylinder housing element (50) having a wall structure defining at least one cylinder space (54) and a cooling fluid jacket (56) for cooling the cylinder housing element (50). A gas channel (58) may extend at least partly inside said cylinder housing element such that said cooling fluid jacket (56) reduces the temperature of a gas in the gas channel (58). Also disclosed is a method of cooling exhaust gas in an exhaust gas recirculation system (10) of an internal combustion engine (12) having a cylinder housing element (50) with a wall structure defining at least one cylinder space (54) and a cooling fluid jacket (56) for cooling the cylinder housing element (50). The method may include circulating a flow of exhaust gas in heat transferring contact with a cooling fluid inside the cooling fluid jacket (56).

Description

Technical Field

The disclosure relates to an internal combustion engine having exhaust gas cooling in the cooling jacket of a cylinder housing element.

Background

Exhaust gas recirculation (EGR) is a technique that is disclosed in, for example, EP-A-0 869 275 . EGR may be used for controlling the generation of undesirable pollutant gases and particulate matter in the operation of internal combustion engines. This technique has proven particularly useful in internal combustion engines used in motor vehicles such as passenger cars, light duty trucks, and other on-road motor equipment. The exhaust gas recirculation technique primarily involves the recirculation of exhaust gas into the intake air supply of the internal combustion engine. This exhaust gas thus reintroduced to the engine cylinder reduces the concentration of oxygen therein, which in turn lowers the maximum combustion temperature within the cylinder and slows the chemical reaction of the combustion process, decreasing the formation of nitrous oxide. Furthermore, the exhaust gases typically contain a portion of unburned hydrocarbon which is burned on its reintroduction into the engine cylinder, which further reduces the emission of exhaust gas by-products which would be emitted as undesirable pollutants from the internal combustion engine.
Another technique useful in the control and reduction of undesirable emissions from internal combustion engines is the use of pressure-charged intake air. This permits the use of relatively smaller cubic displacement and lighter weight internal combustion engines in a machine, for example, a mobile equipment, reducing in turn the specific fuel consumption of the machine and overall mass of the machine necessary to perform a given function. In addition to the benefits of reduced size and mass, the typical pressure-charging device may be controlled to provide improved emissions characteristics. Pressure-charging machines suitable for such applications include the exhaust gas driven turbocharger which is comprised typically of an exhaust gas driven turbine linked to a turbine compressor disposed in the intake air stream to provide compression of the intake air. The typical turbocharger is controlled by providing a gate which controls exhaust gas flow and gates exhaust gas to bypass the exhaust gas turbine and control the charging rate of the turbocharger so that the maximum pressure limits of the associated internal combustion engine are not exceeded.
Still another technique for controlling emissions used by many engine manufactures is the use of aftercooling the intake air thereby reducing the intake manifold temperature. Some of the related art techniques have also considered intercooling the EGR gases by routing the recirculated exhaust gases through an aftercooler. It is known that lower intake manifold temperatures tend to reduce the formation of nitrous oxides found in the exhaust.
When utilizing EGR in a turbocharged internal combustion engine, such as for example a diesel engine, the exhaust gas to be recirculated may preferably be removed upstream of the exhaust gas driven turbine associated with the turbocharger. In many EGR applications, the exhaust gas is diverted directly from the exhaust manifold. Likewise, the recirculated exhaust gas is preferably reintroduced to the intake air stream downstream of the compressor and air-to-air aftercooler. For example, in many EGR applications the recirculated exhaust gas is reintroduced to the intake manifold. Reintroducing the exhaust gas downstream of the compressor and air-to-air aftercooler is preferred due to the reliability and maintainability concerns that arise should the exhaust gas be passed through the compressor and aftercooler.
A disadvantage of cooled EGR is that an aftercooler has to be added to the system. Such an aftercooler may be bulky and in most cases the space that is available for mounting the aftercooler is limited. The number of parts, the assembly costs as well as the maintenance costs may be increased. Further, an EGR system, especially a cooled EGR system, tends to significantly increase the volume of the engine.
The current disclosure aims to alleviate or overcome one or more disadvantages associated with the prior art.

Summary of the Invention

In one aspect of the disclosure, an internal combustion engine is provided which may include a cylinder housing element having a wall structure defining at least one cylinder space and a cooling fluid jacket for cooling the cylinder housing element. A gas channel may extend at least partly inside said cylinder housing element such that said cooling fluid jacket reduces the temperature of a gas in the gas channel.
In another aspect, a method of cooling exhaust gas in an exhaust gas recirculation system of an internal combustion engine may be provided. The internal combustion engine may have a cylinder housing element with a wall structure defining at least one cylinder space and a cooling fluid jacket for cooling the cylinder housing element. The method may include circulating a flow of exhaust gas in heat transferring contact with a cooling fluid inside the cooling fluid jacket.

Brief Description of the Drawings

Fig. 1 shows a schematic view of an embodiment of an internal combustion engine with exhaust gas recirulation;
Fig. 2 shows a cross section of a first embodiment of a cylinder housing element with a gas channel;
Fig. 3 shows a cross section of a second embodiment of a cylinder housing element with a gas channel;
Fig. 4 shows a cross section of a third embodiment of a cylinder housing element with a gas channel;
Fig. 5 shows a cross section over line V-V in Fig. 4;
Fig. 6 shows a cross section of a fourth embodiment of a cylinder housing element with a gas channel; and
Fig. 7 shows a cross section of a fifth embodiment of a cylinder housing element with a gas channel

Detailed Description

Turning now to the drawings and particularly to FIG. 1 there is shown a schematic representation of an embodiment of an internal combustion engine 12 which may have an exhaust gas recirculation (EGR) system 10. The internal combustion engine 12 may, for example, be a turbocharged compression ignition engine 12 (i.e. diesel engine). However, other types of internal combustion engines with or without a turbocharger, are also feasible. The internal combustion engine 12 may include an intake manifold 14 which may be part of an air inlet system for supplying air to a cylinder chamber in the cylinder housing element. The engine 12 may have an exhaust system including an exhaust manifold 16. A turbocharger 18 may be provided having an exhaust gas driven turbine 22 that may be included in the exhaust gas system. The turbocharger 18 may be a fixed geometry turbocharger and may also include an exhaust gas inlet 26 and an exhaust gas outlet 28 that both may be in fluid communication with the exhaust gas driven turbine 22. The exhaust gas driven turbine 22 may be coupled to an intake air compressor 24 that may be part of the intake air system. The turbocharger 18 may further include a fresh intake air conduit 30 and a compressed air exit conduit 32 both of which may be in fluid communication with the air compressor 24. The air intake sytem may also include an air-to-air aftercooler 20. It should be noted that the air-to-air aftercooler 20 may be omitted and that the turbocharger 18 may be omitted.
In an embodiment, the internal combustion engine 12 may a include a cylinder housing element 50 having a wall structure 52 that may define at least one cylinder space 54. The housing element 50 may have a cooling fluid jacket 56 for cooling the cylinder housing element 50. A gas channel 58 may extend at least partly inside said cylinder housing element 50 such that said cooling fluid jacket 56 may reduce the temperature of a gas in the gas channel 58.
The EGR system 10 may include a gas conduit 34. The gas channel 58 may be connected to the gas conduit 34 and may thus have the function of an EGR cooler or heat exchanger for cooling exhaust gas to be recirculated. Optionally, a particulate trap 38 may be present in the gas conduit 34. As seen in FIG. 1, the EGR conduit 34 may be disposed in fluid communication with the exhaust manifold 16 and may be adapted for diverting a flow of exhaust gas from the exhaust manifold 16 to an air inlet system. Preferably, the exhaust gas conduit 34 may be connected to the air inlet system at a position downstream of the turbocharger 18 and air-to-air aftercooler 20 and proximate the intake manifold 14. The diverted flow of exhaust gas from the exhaust manifold 16 via the EGR conduit 34 may be controlled using one or more EGR valves 40 operatively associated with an engine controller 42 or similar such engine control module.
The EGR system 10 may also include intake air bypass conduit 36 for diverting a flow of cooled, compressed intake air from a position downstream of the turbocharger 18 and/or air-to-air aftercooler 20 to the exhaust manifold 16. The diverted flow of cooled, compressed intake air within the bypass conduit 36 may likewise be controlled using a bleed air valve 44 operating under the control of the engine controller 42. It should be noted that the intake air bypass conduit 36 may also be omitted from the system.
Figs. 2, 3, 4, 6, 7 each show a schematical cross-section of an exemplary embodiment of a cylinder housing element 50. The cylinder housing element may be a cylinder block 50 or a cylinder head of an internal combustion engine 12. The cylinder housing element 50 may comprise a wall structure 52 defining a number of cylinder spaces 54. The wall structure 52 may also define a cooling jacket 56 around the cylinder spaces 54. Although Fig. 2 depicts the cylinder spaces 54 as being arranged in a row, this is by no means necessary. The cylinder spaces 54 may be arranged as desired, such a for example according to a straight, flat, V or W cylinder configuration. Likewise, the number of cylinders is arbitrary and can be determined in accordance with the desired engine characteristics. Any number cylinder spaces 54 is possible, starting from one cylinder space 54. The cooling jacket 56 may be part of a cooling circuit 55 through which a cooling fluid, such as water or oil, is circulated. The cooling circuit 55 may further contain a pump 57 to drive the flow of cooling fluid through such a cooling circuit 55. The pump 57 may be driven by the internal combustion engine 12. The pump may also be driven by another motor, such as, for example, an electromotor. The cooling circuit 57 may include a heat exchanger 59 for cooling the cooling fluid which has been heated in the cooling jacket 56. The heat exchanger 59 may, for example, be a vehicle radiator.
The cylinder housing element 50 may include a gas channel 58 that may extend at least partly inside said cylinder housing element such that said cooling fluid jacket reduces the temperature of a gas in the gas channel 58. The shape of the gas channel 58 may be adapted freely to the specific configuration of the engine 12 at hand. Preferably though, it contains one or more bends to allow for an economical packaging of the gas channel inside the cylinder housing element 50.
As shown in the embodiment of Fig. 2, the gas channel 58 may be formed by a conduit 80. The conduit may be provided with cooling surface enlarging elements, such as fins 82, pins, vanes, ribs or the like. Such cooling surface enlarging elements may not only extend on the outside of the conduit 80 into the cooling jacket 56 but also on the inside of the conduit 80 into the gas channel 58. The cooling surface enlarging elements may increase the heat transferring surface of the conduit 80.
As shown in Fig. 3, the gas channel 58 may be formed by a spirally wound conduit 84. A spirally wound conduit 84 may have a large length in a relatively small space, thus providing a large heat transferring surface. Of course, also in this embodiment, the spirally wound conduit 84 may be provided with cooling surface enlarging elements, such as fins, pins, vanes, ribs or the like for increasing the heat transferring surface of the conduit. These cooling surface enlarging elements may be present both at the external and the internal surface of the spirally wound conduit 84.
In another embodiment, as shown in Figs. 4 and 5, the gas channel 58 may be formed by a plate heat exchanger 86. As shown in the embodiment, a number of hollow parallel plates 88 may be provided which may all be connected to a gas inlet 90 and a gas outlet 92. The plates 88 may have cooling surface enlarging elements such as vanes 94, ribs, pins, fins or the like. These cooling surface enlarging elements may be provided at the outside of the hollow plates 88 and extend in the cooling jacket 56. Additionally, such cooling surface enlarging elements may also extend in the gas channel 58. Mounting brackets 96 may be provided that connect the plate heat exchanger 86 to a cover 98 which may be connected to the cylinder housing element 50.
As shown in the embodiment of Fig. 6, the gas channel 58 may also be formed as an integral part of the casting that forms the cylinder housing element 50. The gas channel 58 is enclosed by a part 52a of the same wall structure 52 that may enclose the cylinder spaces 54 and the cooling jacket 56. A gas inlet 100 and a gas outlet 102 may be provided for connecting a exhaust gas recirculation conduit 34 to the gas channel 58. As shown, the wall structure 52 near enclosing the gas channel 58 may have a surface enlarging profile to increase the heat transferring surface. The gas channel 58 thus formed may also have a box-like configuration.
The gas channel 58 may also be partly enclosed by a part 52b of the same wall structure 52 that may enclose the cylinder spaces 54 and the cooling jacket 56. Additionally, the gas channel 58 may also be partly enclosed by a cover plate 104. The cover plate 104 may also include a gas inlet 106 and a gas outlet 108. However, the gas inlet 106 and the gas outlet 108 may also be provided in the wall structure 52 that may be a casting.
Although in the embodiments shown in Figs. 2-7 the hatching seems to indicate that the wall structure enclosing the cylinder spaces 54 and the wall structure enclosing the cooling jacket 56 are one part, for example, one casting, it should be noted that these wall structures may be separate parts. Further, instead of a casting, it is also possible that the wall structure is manufactured in another process, for example, welding.

Industrial Applicability

The present disclosure also provides a method of cooling gas, more specifically exhaust gas in an exhaust gas recirculation system of an internal combustion engine. The engine may have a cylinder housing element 50 with a wall structure 52 defining at least one cylinder space 54 and a cooling fluid jacket 56 for cooling the cylinder housing element 50. The method may include circulating a flow of exhaust gas in heat transferring contact with a cooling fluid inside the cooling fluid jacket 56.
The disclosure is applicable in any type of internal combustion engine having a cooling jacket.
Turning again to FIG. 1, one skilled in the art can appreciate and understand the preferred method of recirculating exhaust gas associated with the illustrated embodiment. Broadly speaking, the disclosed method of recirculating exhaust gas may include the steps of: recirculating a selected volume of exhaust gas from the exhaust manifold 16 to the intake manifold 14 via the EGR conduit 34; and cooling the recirculated exhaust gas in the EGR conduit 34 using cooling fluid in the cooling jacket 56.
Optionally, the method may include: diverting a flow of cool intake air to bypass the engine 12 via a bypass conduit 36. Although not shown, the method may also include the step of concurrently heating the intake air in the bypass conduit 36 using the recirculated exhaust gas. The heated intake air may be fed to the exhaust manifold 16 where it may be used to replace the recirculated exhaust gas. The intake air flowing through the intake air bypass conduit 36 may be combined with the exhaust gas remaining in the exhaust manifold 16 and may be used to drive the exhaust gas driven turbine 22 and associated compressor 24 thereby pressurizing the intake air approximate to the designed boost levels. It should be noted that the bypass conduit 36 and the provision of a flow of bypassed intake air to the exhaust inlet 26 of the turbocharger 18 does not form an essential part of the present disclosure.
In the embodiment illustrated in FIG. 1, the diverted exhaust gas may be driven to the intake manifold 14 by the positive displacement pumping action of one or more designated cylinders. The complete diversion of exhaust gas from one or more cylinders to the EGR conduit 34 may allow the EGR rate to be kept more or less constant without having to throttle the EGR valves 40. In addition, since the exhaust gas may be diverted from the selected cylinders, the diverted exhaust gas may be typically pressurized above that of the exhaust manifold 16 and intake manifold 14. As a consequence, the EGR system 10 may be adapted to operate within a broader range of engine operating conditions (i.e. at high load conditions) and generally may maintain the gas channel 58 extending in heat transferring contact with the cooling fluid inside the cooling fluid jacket 56, free of significant particle build up. As indicated above, there may exist some engine operating conditions, such as high load conditions, where the pressure differential between the intake manifold 14 and the exhaust manifold 16 may prevent many conventional EGR systems from being utilized without expensive and inefficient throttling arrangements in either the exhaust 16 or intake manifolds 14. Likewise, the use of heat exchangers in many conventional EGR systems may be avoided due to the problems associated with soot and particle build up over time. The disclosed embodiment may minimize such problems.
With the foregoing in mind, the depicted method may involve the steps of: (a) receiving fresh intake air 60 at the turbocharger 18; (b) compressing the fresh intake air 60 with turbocharger 18; (c) sending the compressed intake air 62 to the air-to-air aftercooler 20; (d) cooling the compressed intake air 62 using the air-to-air aftercooler 20 to yield cooled compressed intake air 64.
The method may also include the steps of (e) diverting a selected volume of hot exhaust gas 70 from the exhaust manifold 16 of the engine 12; (f) cleansing the diverted hot exhaust gas 70 using a particulate trap 38; (g) cooling the diverted hot exhaust gas 70 using the cooling capacity of cooling fluid inside the cooling jacket; and (h) forwarding the combined intake/EGR gas to the engine 12. Concurrently therewith the method may also include: (i) replacing the hot exhaust gas 70 diverted from the exhaust manifold 16 with intake air 74 which may be heated and combining the intake air 74 with any remaining exhaust gas 76 to form a selected volume of discharge air 78; (j) driving an exhaust gas driven turbine 22 of the turbocharger 18 with the discharge air 78; and (k) forwarding the discharge air 78 to the exhaust system associated with the engine 12.
Because a gas channel 58 is provided which may be in heat transferring contact with the cooling fluid in the cooling jacket 56 an improved component packaging compared to the conventional internal combustion engine with EGR-cooling may be obtained. Further, the number of parts necessary for providing EGR-cooling may be reduced and the amount of assembly operations may be reduced. In addition, the gas channel 58 may be less vulnerable to contamination with particles because the gas channel 58 can be comparatively large, relative to conventional gas/air heat exchangers. Especially, when the gas channel 58 is an integral part of the casting forming the cylinder housing element 50, the number of parts and the number of assembly operations may be reduced drastically relative to the prior art. Consequently, the proposed EGR-cooling is less expensive to manufacture and allows for improved component packaging relative to the prior art.
It will be apparent to those having ordinary skill in the art that various modifications and variations can be made to the disclosed EGR cooling system. Other embodiments will be apparent to those having ordinary skill in the art from consideration of the specification. It is intended that the specification and examples be considered as exemplary only. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims.

Claims

An internal combustion engine comprising:
a cylinder housing element having a wall structure defining at least one cylinder space and a cooling fluid jacket for cooling the cylinder housing element; and

a gas channel extending at least partly inside said cylinder housing element such that said cooling fluid jacket reduces the temperature of a gas in the gas channel.
The internal combustion engine according to claim 1, including an air inlet system for supplying air to at least one cylinder chamber in an associated one of the at least one cylinder space, an exhaust system for exhausting combustion gas from the at least one cylinder chamber to the atmosphere, and an exhaust gas recirculation system for feeding a portion of the exhaust gas from the exhaust system to the air inlet system, wherein the gas channel is part of the exhaust gas recirculation system.
The internal combustion engine according to any of the preceding claims, wherein the cooling fluid jacket is part of a cooling circuit configured for circulating cooling fluid and for extracting heat from the cylinder housing element and for removing the extracted heat.
The internal combustion engine according to any of the preceding claims, wherein the heat conductivity of the gas channel is larger than 20 W/(K·m).
The internal combustion engine according to any of the preceding claims, wherein the gas channel is provided with cooling surface enlarging elements.
The internal combustion engine according to claim 5, wherein the cooling surface enlarging elements are chosen from the group consisting of fins, pins, ribs.
The internal combustion engine according to any one of the preceding claims, wherein the gas channel has a spirally wound configuration.
The internal combustion engine according to any one of the preceding claims, wherein the gas channel includes a box like chamber having chamber walls of which at least one wall is in direct contact with cooling fluid in the cooling jacket.
The internal combustion engine according to any one of the preceding claims, wherein the gas channel includes a plate heat exchanger configuration.
The internal combustion engine according to any of the preceding claims, wherein the cylinder housing element, more specifically the wall structure of the cylinder housing element is a casting, wherein the gas channel is an integral part of the casting.
The internal combustion engine according to any one of the preceding claims, wherein the cylinder housing element is a cylinder block.
The internal combustion engine according to any one of claims 1-10, wherein the cylinder housing element is a cylinder head.
A method of cooling exhaust gas in an exhaust gas recirculation system of an internal combustion engine, the engine having a cylinder housing element with a wall structure defining at least one cylinder space and a cooling fluid jacket for cooling the cylinder housing element, the method comprising:
circulating a flow of exhaust gas in heat transferring contact with a cooling fluid inside the cooling fluid jacket.
The method according to claim 13, wherein the flow of exhaust is diverted from an exhaust gas system before the flow of exhaust gas is circulated in heat transferring contact with the cooling fluid inside the cooling fluid jacket.
The method according to claim 13 or 14, wherein, after the flow of exhaust gas has been brought in heat transferring contact with the cooling fluid inside the cooling fluid jacket, is supplied to an air inlet system of the combustion engine.
The method according to any one of claim 13-15, wherein said cooling fluid includes water.