Internal combustion engine system

Abstract

An internal combustion engine system includes at least one combustor, a compressor arranged to compress air, an air guide arranged to guide compressed air from the compressor to at least one of the at least one combustor, an expander arranged to expand exhaust gases from at least one of the at least one combustor and to extract energy from the expanded exhaust gases, and an exhaust guide arranged to guide exhaust gases from at least one of the at least one combustor to the expander, wherein the exhaust guide is at least partly integrated with the air guide.

Claims

1. An internal combustion engine system comprising at least one combustor, a compressor arranged to compress air, an air guide arranged to guide compressed air from the compressor to at least one of the at least one combustor, an expander arranged to expand exhaust gases from at least one of the at least one combustor and to extract energy from the expanded exhaust gases, and an exhaust guide arranged to guide exhaust gases from at least one of the at least one combustor to the expander, the exhaust guide being at least partly integrated with the air guide, wherein the exhaust guide comprises an integrated portion which is located within the air guide, that the integrated portion presents a wall delimiting the integrated portion and that the integrated portion comprises an insulation layer located inside the wall.

2. A system according to claim 1, wherein the exhaust guide is arranged to penetrate an external wall of the air guide.

3. A system according to claim 1, wherein the integrated portion presents a circular cross section.

4. A system according to claim 1, wherein the intergrated portion presents a plurality of externally protruding flanges.

5. A system according to claim 1, wherein the air guide comprises an air buffer container arranged to provide an air buffer volume for the compressed air.

6. A system according to claim 5, wherein the system comprises a plurality of combustors, and that the air buffer container is arranged to deliver the compressed air to a plurality of the combustors.

7. A system according to claim 5, wherein the system comprises a plurality of compressors and that the air buffer container is arranged to receive compressed air from a plurality of the compressors.

8. A system according to claim 5, wherein the at least part of the exhaust guide is located within the air buffer container.

9. A system according to claim 1, wherein the exhaust guide comprises an exhaust buffer container.

10. A system according to claim 9, wherein the system comprises a plurality of combustors, and that the exhaust buffer container is arranged to receive exhaust gases from a plurality of the combustors.

11. A system according to claim 9, wherein the system comprises a plurality of expanders, and that the exhaust buffer container is arranged to deliver exhaust gases to a plurality of the expanders.

12. A system according to claim 9, wherein the exhaust buffer container is located within the air guide.

13. A system according to claim 5, wherein the exhaust guide comprises an exhaust buffer container, and the exhaust buffer container is located within the air buffer container.

14. A system according to claim 1, wherein a pre-expander exhaust treatment device is located in the exhaust guide, which pre-expander exhaust treatment device is arranged to provide an exhaust treatment process to the exhaust gases from the combustor.

15. A system according to claim 14, wherein the pre-expander exhaust treatment device is located in the integrated portion.

16. A system according to claim 14, wherein the pre-expander exhaust treatment device comprises an oxidation catalyst.

17. A system according to claim 14, wherein the pre-expander exhaust treatment device comprises a particulate filter.

18. A system according to claim 16, wherein the pre-expander exhaust treatment device comprises a particulate filter, and the particulate filter is located downstream of the oxidation catalyst.

19. A system according to claim 1, wherein the system comprises a post-expander exhaust treatment device arranged to receive exhaust gases from the expander and to provide an exhaust treatment process to the received exhaust gases.

20. A system according to claim 19, wherein the post-expander exhaust treatment device is a selective catalytic reduction (SCR) catalyst.

21. A system according to claim 19, wherein the post-expander exhaust treatment device and the air guide are integrated with each other.

22. A system according to claim 19, wherein the post-expander exhaust treatment device is located within the air wide.

23. A system according to claim 19, wherein the post-expander exhaust treatment device is located externally of the integrated portion and internally of an external wall of the air guide.

24. A system according to claim 23, wherein a pre-expander exhaust treatment device is located in the integrated portion which pre expander exhaust treatment device is arranged to provide an exhaust treatment process to the exhaust gases from the combustor.

25. A system according to claim 19, wherein the expander is a first expander and that the system comprises a second expander arranged to receive and expand exhaust gases.

26. A system according to claim 1, wherein the system comprises a crankshaft, and that the at least one combustor comprises a piston arranged to reciprocate in a cylinder, and to drive the crankshaft.

27. A system awarding to claim 1, wherein the compressor is a piston compressor.

28. A system according to claim 1, wherein the system comprises a crankshaft and that the compressor is arranged to be driven by the crankshaft.

29. A system according to claim 1, wherein the expander is a piston expander.

30. A system according to claim 1, wherein the system comprises a crankshaft, and that the expander is arranged to drive the crankshaft with the extracted energy.

31. A vehicle provided with an internal combustion engine system according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples. In the drawings:

(2) FIG. 1 is a partially sectioned side view of a vehicle in the form of a truck.

(3) FIG. 2 is a schematic perspective view of an engine system in the vehicle in FIG. 1.

(4) FIG. 3 is a schematic cross-sectional view of the engine system in FIG. 2.

(5) FIG. 4 shows a detail in FIG. 3.

(6) FIG. 5 shows a cross-section oriented as indicated with the arrows V-V in FIG. 4.

(7) FIG. 6 is a schematic cross-sectional view of an engine system according to an alternative embodiment of the invention.

(8) FIG. 7 shows a detail in FIG. 6.

(9) FIG. 8 shows a cross-section oriented as indicated with the arrows VIII-VIII in FIG. 7.

(10) FIG. 9 shows a cross-section oriented as indicated with the arrows IX-IX in FIG. 8.

(11) FIG. 10 is a schematic cross-sectional view of an engine system according to another alternative embodiment of the invention.

(12) FIG. 11 is a schematic perspective view of an engine system according to yet another embodiment of the invention.

DETAILED DESCRIPTION

(13) FIG. 1 shows a vehicle in the form of a truck, or a tractor for a semitrailer. It should be noted however that the invention is applicable to a variety of alternative types of vehicles, such as a car, a bus, or a working machine such as a wheel loader. The vehicle comprises an internal combustion engine system 1.

(14) FIG. 2 is schematic and does not show, for simplicity of this presentation, certain parts such as devices for the actuation of inlet and outlet valves in cylinders of the engine system. The engine system 1 comprises a multi-stage compression and expansion internal combustion engine. The engine comprises three combustors 3, in the form of cylinders with pistons, and three piston compressors 4.

(15) The system further comprises an air guide 5 arranged to guide compressed air from the compressors 4 to the combustors 3. The air guide is provided with an air buffer container 51, arranged to receive compressed air from the compressors 4, to provide an air buffer volume 511 for the compressed air, and to deliver the compressed air to the combustors 3.

(16) The system farther comprises three piston expanders 6 arranged to expand exhaust gases from the combustors 3 and to extract energy from the expanded exhaust gases. An exhaust guide 9 is arranged to guide exhaust gases from the combustors 3 to the expanders 6. The exhaust guide 9 comprises an exhaust buffer container 91 described closer below.

(17) It is understood that the engine system may comprise any number of combustors 3, compressors 4, and expanders 6. In this example, the combustors 3, compressors 4, and expanders 6 share a single air buffer 51 and a single exhaust buffer container 91. However, the number of air guides 5, air buffers 51, exhaust guides 9, and exhaust buffer containers 91 may vary as well. For example, it is conceivable that a plurality of air guides 5 with respective air buffers 51 extend between respective pairs of compressors 4 and combustors 3. Also, in some embodiments, there may be more than one exhaust guide 9 with respective exhaust buffer containers 91 extending between respective pairs of combustors 3 and expanders 6. In is also conceivable that there are two or more air guides, and two or more exhaust guides, connected to respective groups of combustors.

(18) Reference is made to FIG. 3 in which only one of the combustors 3, only one of compressors 4, and only one of the expanders 6 are shown. The piston 301 of each combustor 3 is arranged to reciprocate in the respective cylinder 302, whereby the pistons are all arranged to drive a crankshaft 2 of the engine. For simplicity, the combustor 3, the compressor 4, and the expander 6 are shown as all being located in the same cross-sectional plane; in a real implementation of the embodiment, the combustor 3, the compressor 4, and the expander 6 are preferably offset in relation to each other along the crankshaft 2.

(19) The combustors 3 are provided with respective sets of inlet and outlet valves 303, 304, arranged to be actuated in a manner which may be known per se, e.g. with cams mounted on camshafts, (not shown). The timing and the maximum movements of the valves 303, 304 may also be variable, as is also known per se.

(20) In addition, the combustors 3 are provided with respective fuel injectors 305 for injecting a fuel into the cylinders 302. In example, the combustors 3 are arranged to provide a Diesel cycle to extract work from the air and fuel provided. However, the invention is equally applicable to engines in which the combustors are arranged to provide an Otto cycle, wherein the engine system may be provided with means for air mass flow control, such as variable inlet and outlet valves of the compressors 4, for controlling the air supply to the combustors 3. Alternatively, or in addition, the means for air mass flow control may comprise one or more throttles, for controlling the air supply to the combustors 3. The engine system may be provided with spark plugs in the combustors.

(21) The pistons 601 of the expanders 6 are arranged to drive the crankshaft 2 with the energy extracted from the exhaust gases from the combustors 3. Further, the pistons 401 of the compressors 4 are all arranged to be driven by the crankshaft 2.

(22) The exhaust buffer container 91 is located within the air buffer container 51. Thereby, the exhaust guide 9 is arranged to penetrate an external wall of the air buffer container 51. Thus, the exhaust buffer container 91 forms an integrated portion 91 of the exhaust guide 9, whereby the exhaust guide 9 is partly integrated with the air guide 5. The integrated portion 91 is herein also referred to as an exhaust guiding portion 91. The air buffer container 51 is herein also referred to as a formn of air guiding portion 51. The exhaust guiding portion 91 and the air guiding portion 51, with the former located within the latter, is here also referred to as an exhaust guiding unit.

(23) It should be noted that in some embodiments, where there are two or more air guides 5, and two or more exhaust guides 9, connected to respective groups of combustors 3, the integration may be provided between an air guide and an exhaust guide which are connected to the same group of combustors 3, or alternatively to separate groups of combustors 3.

(24) Reference is made also to FIG. 4 and FIG. 5. A pre-expander exhaust treatment device 7, 8 is located in the exhaust buffer container 91, and arranged to provide an exhaust treatment process to the exhaust gases from the combustors 3. The pre-expander exhaust treatment device 7, 8 comprises an oxidation catalyst 7, and a particulate filter 8 located downstream of the oxidation catalyst 7.

(25) The exhaust buffer container 91 presents a circular cross-section. The exhaust buffer container 91 presents a wall 901, delimiting the exhaust buffer container 91, and an insulation layer 902 located inside the wall. The exhaust buffer container 91 further presents a plurality of externally protruding flanges 903.

(26) Thus, in the multi-stage compression and expansion engine in this example, the compressors 4 are arranged to compress the air, the combustors are arranged to compress the air further, and to expand the gases in the combustors 3, and the expanders are arranged to expand the gases further. Further, the exhaust buffer container 91 and the air buffer container 51 may be adapted for an operation of the engine system 1, in which the exhaust guide 9 presents a pressure within the range of 10-25 bar and temperature within the range of 300-950 C., and the air guide 5 presents a pressure within the range of 8-12 bar and a temperature within the range of 250-350 C.

(27) Since the exhaust buffer container 91 is located within the air buffer container 51, the pressure difference across the wall 901 of the exhaust buffer container 91 is considerably reduced, compared to a case where the exhaust buffer container 91 is in direct contact with the surrounding atmosphere. This reduces the structural load on the exhaust buffer container 91.

(28) In addition, the movement of the compressed air past the exhaust buffer container 91 provides for an exchange of heat from the exhaust buffer container 91 to the air. This heat exchange is augmented by the flanges 903 on the exhaust buffer container 91. Also, the heat exchange is increased by the elevated absolute pressure in the air buffer container 51. This heat exchange provides for reusing the heat for power production, which is of particular interest at a low load operation of the engine. Also, the heat transfer reduces the temperature load on the material of the exhaust buffer container 91.

(29) Reference is made to FIG. 6, showing an engine system according to an alternative embodiment of the invention. This embodiment shares features with the embodiment described with reference to FIG. 2-FIG. 5. However, some further advantageous features are also provided.

(30) The system in FIG. 6 comprises an exhaust buffer container 91 with an exhaust treatment device 7, 8, similar to the one in the embodiment described with reference to FIG. 2-FIG. 5, which is here referred to as a pre-expander exhaust treatment device 7, 8. The system in FIG. 6 further comprises a post-expander exhaust treatment device 11 in the form of a selective catalytic reduction (SCR) catalyst. The SCR catalyst 11 is arranged to receive exhaust gases from the expanders 6 and to provide an exhaust treatment process to the received exhaust gases, which process reduces nitrogen oxides (NOx) as is known per se. The system also comprises an injector (not shown) for injecting, a reductant for the process in the SCR catalyst 11.

(31) Reference is made also to FIG. 7-FIG. 9. In this advantageous embodiment, the post-expander exhaust treatment device 11, the air guide 5, and the exhaust guide 9 are integrated with each other. More specifically, the post-expander exhaust treatment device 11 is located externally of the exhaust buffer container 91 and internally of an external wall of the air buffer container 51. The post-expander exhaust treatment device 11 is located partly adjacent to the pre-expander exhaust treatment device 7, 8, separated by the wall of the exhaust buffer container 91, which in this example presents a rectangular cross-section with rounded corners. The integrated pre-expander exhaust treatment device 7, 8 and post-expander exhaust treatment device 11 is herein also referred to as an exhaust treatment unit.

(32) The embodiment in FIG. 6-FIG. 9 comprises an expander 6 similarly to the embodiment in FIG. 2-FIG. 5, here referred to as a first expander 6. In addition, the system in FIG. 6 comprises a second expander 12 arranged to receive and expand exhaust gases from the post-expander exhaust treatment device 11 and to extract energy from the expanded exhaust gases.

(33) The integrated pre-expander exhaust treatment device 7, 8 and post-expander exhaust treatment device 11 provides an advantageous heat transfer from the pre-expander exhaust treatment device 7, 8 to the post-expander exhaust treatment device 11. This is particularly advantageous, since the first expander 6 extracts energy, i.e. heat from the exhaust gases, and by the heat transfer from the pre-expander exhaust treatment device 7, 8, the temperature in the post-expander exhaust treatment device 11 may be kept high enough for the process therein. In addition, the second expander 12 may extract energy provided by the heat production of the process in the post-expander exhaust treatment device 11. The system is arranged so that during an operation thereof, the post-expander exhaust treatment device 11 presents a pressure within the range of 4-8 bar, and a temperature within the range of 250-400 C.

(34) In alternative embodiments, the second expander 12 could be a turbine of a turbo charger with a compressor located upstream of the piston compressor 4. In such embodiments, the post-expander exhaust treatment device 11 may present a pressure within the range of 1.5-2.0 bar

(35) Reference is made to FIG. 10. It is understood that the invention is applicable also to engine systems, where pistons of the compressors 4 and the expanders 6 are indirectly connected to the crankshaft 2, e.g. via an additional crankshaft 2b and a chain or belt connection 201, as shown in FIG. 10. In FIG. 10, the pistons of the compressors 4 and the expanders 6 are directly connected to the additional crankshaft 2b, and the chain or belt connection 201 is provided between the crankshafts 2, 2b. Any suitable type of connection between the crankshafts 2, 2b may be provided. For example, as an, alternative to the chain or belt connection 201, a toothed gear wheel connection between the crankshafts 2, 2b may be provided.

(36) It is to be understood that the present invention is not limited to the embodiments described a hove and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

(37) Reference is made to FIG. 11, showing an engine system according to yet another embodiment of the invention. This embodiment shares features with the embodiment described with reference to FIG. 2-FIG. 5. However, a further advantageous features is also provided.

(38) In this embodiment, the exhaust guide 9 substantially fully integrated with the air guide 5. More specifically, in addition to the exhaust buffer container 91 being located within the air buffer container 51, other portions of the exhaust guide 9, upstream and downstream of the exhaust buffer container 91, are located within the air guide 5. Thereby the air guide encloses the exhaust guide 9 from a vicinity of the combustors 3 to a vicinity of the expanders 6. At the combustors 3 and the expanders 6, the exhaust guide 9 penetrates the external wall of the air guide 5. In other words, an integrated portion of the exhaust guide 91, enclosed by the air guide, extends from an exhaust guide location in a vicinity of the combustors 3 to an exhaust guide location in a vicinity of the expanders 6.

(39) The embodiment FIG. 11 for most of, or substantially all of the exhaust guide 9 being isolated by the air guide 5. This reduces the temperature of the wall material of the exhaust guide 9, which makes it possible to use less temperature resistant, and therefore cheaper material for the exhaust guide. Also, the isolation of the exhaust guide 9 by the air guide 5 provides for reducing the heat radiation around the exhaust guide 9, without the need to provide isolation material around the exhaust guide 91. This is a substantial advantage in vehicles, where space requirements are strict. The possibility to omit isolation material for the exhaust guide 9 reduces the volume of the engine system, as well as the cost therefore,