CN216788547U - Split-cylinder circulating internal combustion engine - Google Patents

Abstract

The utility model discloses a split-cylinder cycle internal combustion engine. Which includes a crankshaft, a compression cylinder, a first combustion cylinder in communication with the compression cylinder, a second combustion cylinder in communication with the compression cylinder, an expansion cylinder, and a control device. The compression cylinder has a compression piston connected to the crankshaft. The first combustion cylinder has a first combustion piston connected to the crankshaft. The second combustion cylinder has a second combustion piston connected to the crankshaft, the first combustion piston moving in synchronism with the second combustion piston. The expansion cylinder has an expansion piston connected to the crankshaft, the expansion cylinder is in communication with both the first combustion cylinder and the second combustion cylinder, and the expansion piston moves in synchronization with the compression piston. When the compression piston and the expansion piston are both at the bottom dead center, the first combustion piston and the second combustion piston are simultaneously at the top dead center. According to the split cylinder cycle internal combustion engine, the compression cylinder and the expansion cylinder have no invalid stroke, so that the power density and the heat efficiency are greatly improved.

Description

Split-cylinder circulating internal combustion engine

Technical Field

The utility model relates to the technical field of machinery, in particular to a split-cylinder cycle internal combustion engine.

Background

The thermal efficiency of diesel engines determines the economy of diesel engines and the carbon emission characteristics, and therefore, the research on the thermal efficiency of diesel engines is an active field. The cylinder-separating circulation technology is one of means for raising the heat efficiency of diesel engine, and the technology decomposes the air intake, compression, expansion and exhaust processes of traditional diesel engine and realizes complete work circulation by using multiple cylinders.

However, the conventional split-cylinder cycle diesel engine has low thermal efficiency because the actual compression ratio is low, the charging efficiency is low, and the complete expansion of the exhaust gas cannot be achieved. In addition, the existing cylinder-divided cycle machine has low power density because of the ineffective stroke of the compression and expansion cylinder.

Therefore, there is a need for a split-cylinder cycle internal combustion engine that at least partially addresses the above problems.

SUMMERY OF THE UTILITY MODEL

In the summary section a series of concepts in a simplified form is introduced, which will be described in further detail in the detailed description section. The inventive content of the present invention is not intended to define key features or essential features of the claimed solution, nor is it intended to be used to limit the scope of the claimed solution.

To at least partially solve the above problems, the present invention provides a split-cylinder cycle internal combustion engine comprising:

a crank shaft;

a compression cylinder having a compression piston connected to the crankshaft;

a first combustion cylinder having a first combustion piston connected to the crankshaft, the first combustion cylinder communicating with the compression cylinder to receive gas therefrom;

a second combustion cylinder having a second combustion piston connected to said crankshaft, said second combustion cylinder communicating with said compression cylinder to receive gas therefrom, said first combustion piston moving in synchronization with said second combustion piston;

an expansion cylinder having an expansion piston connected to the crankshaft, the expansion cylinder communicating with both the first combustion cylinder and the second combustion cylinder to receive gas therefrom, the expansion piston synchronized with the compression piston;

when the compression piston and the expansion piston are both at the bottom dead center, the first combustion piston and the second combustion piston are simultaneously at the top dead center.

Further, a first fuel injector is arranged in the middle of the top of the first combustion cylinder, a second fuel injector is arranged in the middle of the top of the second combustion cylinder, the split-cylinder-cycle internal combustion engine further comprises a control device, the control device is in signal connection with the first fuel injector and the second fuel injector, and the control device is configured to: and when the first combustion piston is positioned at the top dead center each time, controlling one of the first oil injector and the second oil injector to inject oil, wherein the first oil injector and the second oil injector inject oil alternately in sequence.

Further, the compression cylinder is provided with:

a first gas delivery valve through which the compression cylinder communicates with the first combustion cylinder;

a second gas delivery valve through which the compression cylinder communicates with the second combustion cylinder;

the control device is in signal connection with the first air supply valve and the second air supply valve, and is configured to control one of the first air supply valve and the second air supply valve to be opened when the compression piston is located at a lower dead point each time, and the first air supply valve and the second air supply valve are sequentially and alternately opened; and is

When the first air supply valve is opened, the second oil sprayer sprays oil, and when the second air supply valve is opened, the first oil sprayer sprays oil; and is

And when the compression piston moves from the top dead center to the bottom dead center every time, controlling the first air supply valve and the second air supply valve to be closed.

Furthermore, the compression cylinder is also provided with at least one suction valve, and the control device is in signal connection with the at least one suction valve;

wherein the control device is configured to control the at least one suction valve to close when one of the first and second air supply valves is open; and is

Controlling the at least one suction valve to open when both the first and second supply valves are closed.

Further, the first combustion cylinder includes a first variable timing intake valve in communication with the first air bleed valve through a first intake pipe;

the second combustion cylinder includes a second variable timing intake valve in communication with the second air bleed valve through a second intake pipe;

the control device is in signal communication with both the first variably timed intake valve and the second variably timed intake valve, the first intake pipe and the second intake pipe configured to store gas.

Further, the first combustion cylinder comprises a first exhaust valve, the expansion cylinder comprises a first expansion valve, and the first exhaust valve is communicated with the first expansion valve;

the second combustion cylinder includes a second exhaust valve, the expansion cylinder includes a second expansion valve, and the second exhaust valve is in communication with the second expansion valve;

the first exhaust valve and the first expansion valve are synchronously opened and closed, and the second exhaust valve and the second expansion valve are synchronously opened and closed; and is

The control device is in signal connection with the first exhaust valve, the second exhaust valve, the first expansion valve and the second expansion valve, and the control device is configured to:

when the first fuel injector injects fuel and the first combustion piston moves from the top dead center to the bottom dead center, controlling the first exhaust valve to be opened and the second exhaust valve to be closed;

when the second fuel injector injects fuel and the second combustion piston moves from the top dead center to the bottom dead center, the second exhaust valve is controlled to be opened, and the first exhaust valve is controlled to be closed;

and controlling the first exhaust valve and the second exhaust valve to be closed when the combustion piston moves from the top dead center to the bottom dead center.

Further, the expansion cylinder also comprises at least one air outlet valve, and the control device is in signal connection with the at least one air outlet valve;

wherein the control device is configured to: controlling the at least one outlet valve to close when one of the first expansion valve and the second expansion valve is open; and is

And when the first expansion valve and the second expansion valve are both closed, controlling the at least one air outlet valve to be opened.

Further, the volume of the expansion cylinder is 2-2.5 times of the volume of the compression cylinder; and/or

The first combustion cylinder and the second combustion cylinder have the same volume, and the compression cylinder has a volume 3 times or more the volume of the first combustion cylinder.

Further, a heat insulation layer is wrapped outside the expansion cylinder.

Further, the first combustion cylinder and the second combustion cylinder are arranged in a V-shape.

Further, the crankshaft includes a main journal and first, second, third, and fourth journals protruding from the main journal, the first journal being connected to the compression piston, the second journal being connected to the first combustion piston, the third journal being connected to the second combustion piston, and the fourth journal being connected to the expansion piston;

wherein a phase difference between the first crank journal and the second crank journal in a circumferential direction around the main journal is 180 °, a phase difference between the second crank journal and the third crank journal in the circumferential direction around the main journal is 0 °, and a phase difference between the third crank journal and the fourth crank journal in the circumferential direction around the main journal is 0 °.

According to the split-cylinder cycle internal combustion engine, the compression cylinder and the expansion cylinder respectively have one combustion cylinder to do work each time in a reciprocating manner, so that the compression cylinder and the expansion cylinder have no invalid stroke, the power density is greatly improved, and the thermal efficiency of the internal combustion engine is improved.

Drawings

The following drawings of the utility model are included to provide a further understanding of the utility model. The drawings illustrate embodiments of the utility model and, together with the description, serve to explain the principles of the utility model.

In the drawings:

FIG. 1 is a schematic side view of a split-cylinder cycle internal combustion engine according to a preferred embodiment of the present invention;

FIG. 2 is a schematic top view of a split-cylinder cycle internal combustion engine according to a preferred embodiment of the present invention; and

FIG. 3 is a schematic sectional view taken along the line A-A' in FIG. 2.

Description of reference numerals:

100: split-cylinder cycle internal combustion engine 110: crank shaft

120: the compression cylinder 121: compression piston

122: first air feed valve 123: second air supply valve

124: the suction valve 125: air suction pipe

130: first combustion cylinder 131: first combustion piston

132: first variable-timing intake valve 133: first air inlet pipe

134: first exhaust valve 135: first fuel injector

136: first exhaust pipe 140: second combustion cylinder

141: second combustion piston 142: second variable timing intake valve

143: second intake pipe 144: second exhaust valve

145: second injector 146: second exhaust pipe

150: the expansion cylinder 151: expansion piston

152: first expansion valve 153: second expansion valve

154: the air outlet valve 155: thermal insulation layer

156: air outlet pipe

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the utility model.

In the following description, a detailed description will be given in order to thoroughly understand the present invention. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art. It is apparent that the implementation of the embodiments of the utility model is not limited to the specific details familiar to those skilled in the art. The following detailed description of the preferred embodiments of the utility model, however, the utility model is capable of other embodiments in addition to those detailed.

It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the utility model. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Ordinal words such as "first" and "second" are referred to herein merely as labels, and do not have any other meaning, such as a particular order, etc. Also, for example, the term "first component" does not itself imply the presence of "second component", and the term "second component" does not itself imply the presence of "first component". It is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like are used herein for purposes of illustration only and are not limiting.

An exemplary embodiment according to the present invention will now be described in more detail with reference to fig. 1 to 3. Referring first to fig. 1 and 2, a split-cylinder cycle internal combustion engine 100 of a preferred embodiment of the present invention includes a crankshaft 110, a compression cylinder 120, a first combustion cylinder 130, a second combustion cylinder 140, an expansion cylinder 150, and a control device (not shown). The control means may be a processor, chip or circuit board or the like.

Therein, the compression cylinder 120 has a compression piston 121, and the compression piston 121 is connected to the crankshaft 110. The first combustion cylinder 130 has a first combustion piston 131, and the first combustion piston 131 is connected to the crankshaft 110. The second combustion cylinder 140 has a second combustion piston 141, the second combustion piston 141 being connected to the crankshaft 110. The expansion cylinder 150 has an expansion piston 151, and the expansion piston 151 is connected to the crankshaft 110. That is, the compression piston 121, the first combustion piston 131, the second combustion piston 141, and the expansion piston 151 are all connected to the same crankshaft 110. Preferably, the first combustion cylinder 130 and the second combustion cylinder 140 are arranged in a V shape to increase power density. An insulating layer 155 is preferably disposed outside the expansion cylinder 150 to fully utilize waste heat and improve thermal efficiency. In the present embodiment, the internal combustion engine 100 completes one complete intake, compression, combustion, and exhaust process for each 2 revolutions of the crankshaft 110, i.e., 720 °, in a split-cylinder cycle.

The compression cylinder 120 communicates with both the first combustion cylinder 130 and the second combustion cylinder 140 to provide pre-compressed air thereto. The expansion cylinder 150 communicates with both the first combustion cylinder 130 and the second combustion cylinder 140 to receive combustion exhaust gas produced by both.

And, the first combustion piston 131 and the second combustion piston 141 move in synchronization, that is, both reach the top dead center or the bottom dead center at the same time. Or both, the crank phase is the same or 360 deg.. Preferably, the compression piston 121 is synchronized with the expansion piston 151, and when both the compression piston 121 and the expansion piston 151 are at bottom dead center, the first combustion piston 131 and the second combustion piston 141 are at top dead center at the same time. When both the compression piston 121 and the expansion piston 151 are at the top dead center, the first combustion piston 131 and the second combustion piston 141 are at the bottom dead center at the same time. Illustratively, the compression piston 121 is 180 ° out of crank phase with the first combustion piston 131 and the compression piston 121 is 540 ° out of crank phase with the second combustion piston 141. The expansion piston 151 is 180 ° out of crank phase with the first combustion piston 131, and the expansion piston 151 is 540 ° out of crank phase with the second combustion piston 141.

Illustratively, the crankshaft includes a main journal (not shown) and first (not shown), second (not shown), third (not shown), and fourth (not shown) journals protruding from the main journal. The first crank journal is connected to the compression piston 121, the second crank journal is connected to the first combustion piston 131, the third crank journal is connected to the second combustion piston 141, and the fourth crank journal is connected to the expansion piston 151. The phase difference between the first crank journal and the second crank journal in the circumferential direction around the main journal is 180 °, the phase difference between the second crank journal and the third crank journal in the circumferential direction around the main journal is 0 °, and the phase difference between the third crank journal and the fourth crank journal in the circumferential direction around the main journal is 0 °.

Preferably, when the first combustion cylinder 130 and the second combustion cylinder 140 are in a V-shaped arrangement, the second and third crank journals may be the same, i.e., the V-shaped arrangement of the first combustion cylinder 130 and the second combustion cylinder 140 is connected to the same crank journal.

The top of first combustion cylinder 130 and the top of second combustion cylinder 140 are provided with first injector 135 and second injector 145, respectively. And the control device is in signal connection with both the first injector 135 and the second injector 145. The control means are configured to control one of first injector 135 and second injector 145 to inject fuel each time first combustion piston 131 is at top dead centre, and first injector 135 and second injector 145 inject fuel alternately in sequence. In other words, the crank phase difference of first injector 135 and second injector 145 is 360 °. Alternatively, the first combustion piston 131 is 360 ° out of crank phase with the second combustion piston 141. Such that one combustion cylinder performs work during each 360 rotation of crankshaft 110.

In accordance with the split-cylinder cycle engine 100 of the present invention, the compression cylinder 120 and the expansion cylinder 150 have one combustion cylinder doing work per reciprocation, such that there are no lost motion strokes for the compression cylinder 120 and the expansion cylinder 150. That is, one combustion cylinder is used for air intake when the compression piston 121 ascends each time, and one combustion cylinder is used for air exhaust when the expansion piston 151 descends each time, so that the power density is greatly improved, and the thermal efficiency of the internal combustion engine is improved.

Specifically, refer to fig. 2 and 3. The compression cylinder 120 is provided with a first air bleed valve 122, a second air bleed valve 123 and at least one suction valve 124. The control means is in signal connection with the first air bleed valve 122, the second air bleed valve 123 and the at least one suction valve 124. The compression cylinder 120 communicates with the first combustion cylinder 130 through the first air delivery valve 122 and communicates with the second combustion cylinder 140 through the second air delivery valve 123. The suction valve 124 sucks air from the outside through the suction pipe 125, and in the present embodiment, two suction valves 124 are provided.

The control means is configured to control one of the first and second air supply valves 122 and 123 to be opened each time the compression piston 121 is located at the bottom dead center, and the first and second air supply valves 122 and 123 are alternately opened in sequence. That is, the crank phase difference between the first air feed valve 122 and the second air feed valve 123 is 360 °.

And second injector 145 injects fuel when first supply valve 122 is opened, and first injector 135 injects fuel when second supply valve 123 is opened. When the compression piston 121 moves from the top dead center to the bottom dead center each time, the first and second air supply valves 122 and 123 are controlled to be closed. In other words, the crank phase of first delivery valve 122 and first injector 135 is 360 °, and the crank phase of second delivery valve 123 and second injector 145 is 360 °.

And, the control means controls at least one of the suction valves 124 to be closed when one of the first and second air supply valves 122 and 123 is opened, and controls at least one of the suction valves 124 to be opened when both of the first and second air supply valves 122 and 123 are closed. Illustratively, at least one suction valve 124 is crank phased 180 ° from the first feed valve 122, and at least one suction valve 124 is crank phased 540 ° from the second feed valve 123.

With continued reference to FIG. 2, the first combustion cylinder 130 is provided with a first variable timing intake valve 132 which communicates with the first induction valve 122 through a first intake pipe 133. The second combustion cylinder 140 is provided with a second variable timing intake valve 142 that communicates with the second air feed valve 123 via a second intake pipe 143. The control means is in signal communication with both the first variably-timed intake valve 132 and the second variably-timed intake valve 142 to control the first variably-timed intake valve 132 to open as the first combustion cylinder 130 enters the intake stroke and to control the second variably-timed intake valve 142 to open as the second combustion cylinder 140 enters the intake stroke. In this case, since the opening and closing of the first variable-timing intake valve 132 and the first air feed valve 122, and the second variable-timing intake valve 142 and the second air feed valve 123 may not be synchronized, the first intake pipe 133 and the second intake pipe 143 are configured to store gas so that the combustion cylinder can be fully charged. In the present embodiment, the provision of the variable timing intake valve enables the split-cylinder cycle internal combustion engine 100 to have a variety of operating conditions, i.e., to be adapted to the conditions of variable operating conditions, which is advantageous in energy saving.

With continued reference to fig. 2, expansion cylinder 150 is provided with a first expansion valve 152, a second expansion valve 153, and at least one outlet valve 154. The first combustion cylinder 130 is also provided with a first exhaust valve 134 and the second combustion cylinder 140 is also provided with a second exhaust valve 144.

The first exhaust valve 134 and the first expansion valve 152 communicate with each other through the first exhaust pipe 136, and the second exhaust valve 144 and the second expansion valve 153 communicate with each other through the second exhaust pipe 146. The outlet valve 154 exhausts to the outside through an outlet pipe 156. In the present embodiment, two air outlet valves 154 are provided. The control device is in signal connection with the first expansion valve 152, the second expansion valve 153, the first exhaust valve 134, the second exhaust valve 144 and the at least one outlet valve 154.

The first exhaust valve 134 is opened and closed in synchronization with the first expansion valve 152, and the second exhaust valve 144 is opened and closed in synchronization with the second expansion valve 153. And the control means are configured to control the first exhaust valve 134 to open and the second exhaust valve 144 to close when the first combustion piston 131 moves from top dead centre to bottom dead centre after injection of the first injector 135. When the second injector 145 injects fuel and the second combustion piston 141 moves from the top dead center to the bottom dead center, the second exhaust valve 144 is controlled to be opened and the first exhaust valve 134 is controlled to be closed. That is, the first exhaust valve 134 is opened 360 ° out of crank phase with the second exhaust valve 144, and the first exhaust valve 134 is 360 ° out of crank phase with the first injector 135, and the second exhaust valve 144 is 360 ° out of crank phase with the second injector 145. The first exhaust valve 134 and the second exhaust valve 144 are both controlled to close during the travel of the combustion piston from top dead center to bottom dead center.

When one of the first expansion valve 152 and the second expansion valve 153 is opened, the at least one air outlet valve 154 is controlled to be closed, and when both the first expansion valve 152 and the second expansion valve 153 are closed, the at least one air outlet valve 154 is controlled to be opened. Illustratively, the at least one outlet valve 154 is 180 ° out of crank phase with the first expansion valve 152 and the at least one outlet valve 154 is 540 ° out of crank phase with the second expansion valve 153.

In an alternative embodiment, the volume of the expansion cylinder 150 is 2-2.5 times the volume of the compression cylinder 120. Preferably, the volume of the expansion cylinder 150 is 2.3 times the volume of the compression cylinder 120. This allows the exhaust gas to be fully expanded, i.e., expanded to a normal pressure, in the expansion cylinder 150, and work to be performed by the exhaust gas to the maximum extent.

Alternatively, in the present embodiment, the volumes of the first combustion cylinder 130 and the second combustion cylinder 140 are preferably the same. Further, the volume of the compression cylinder 120 is 3 times or more the volume of the first combustion cylinder 130, so that the first combustion cylinder 130 and the second combustion cylinder 140 can be sufficiently charged, and the heat efficiency is improved.

In an embodiment not shown, the volumes of the first combustion cylinder 130 and the second combustion cylinder 140 may be set according to actual needs.

The thermal efficiency of the split-cylinder cycle engine 100 according to the present invention can reach over 57%.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. Features described herein in one embodiment may be applied to another embodiment, either alone or in combination with other features, unless the feature is not applicable or otherwise stated in the other embodiment.

The present invention has been illustrated by the above embodiments, but it should be understood that the above embodiments are for illustrative and descriptive purposes only and are not intended to limit the utility model to the scope of the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications may be made in accordance with the teachings of the present invention, which variations and modifications are within the scope of the present invention as claimed. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims (10)

1. A split-cylinder-cycle internal combustion engine, comprising:

a crank shaft;

a compression cylinder having a compression piston connected to the crankshaft;

a first combustion cylinder having a first combustion piston connected to the crankshaft, the first combustion cylinder communicating with the compression cylinder to receive gas therefrom;

a second combustion cylinder having a second combustion piston connected to said crankshaft, said second combustion cylinder communicating with said compression cylinder to receive gas therefrom, said first combustion piston moving in synchronization with said second combustion piston;

an expansion cylinder having an expansion piston connected to the crankshaft, the expansion cylinder communicating with both the first combustion cylinder and the second combustion cylinder to receive gas therefrom, the expansion piston moving in synchronization with the compression piston;

wherein the first and second combustion pistons are simultaneously at top dead center when both the compression piston and the expansion piston are at bottom dead center.

2. The cylinder-split-cycle internal combustion engine of claim 1, wherein a first fuel injector is disposed in the middle of the top of the first combustion cylinder, a second fuel injector is disposed in the middle of the top of the second combustion cylinder, and the cylinder-split-cycle internal combustion engine further comprises a control device in signal connection with both the first fuel injector and the second fuel injector, the control device being configured to: and when the first combustion piston is positioned at the top dead center each time, controlling one of the first oil injector and the second oil injector to inject oil, wherein the first oil injector and the second oil injector inject oil alternately in sequence.

3. The split-cylinder cycle internal combustion engine of claim 2, wherein the compression cylinder is provided with:

a first gas delivery valve through which the compression cylinder communicates with the first combustion cylinder;

a second gas delivery valve through which the compression cylinder communicates with the second combustion cylinder;

the control device is in signal connection with the first air supply valve and the second air supply valve, and is configured to control one of the first air supply valve and the second air supply valve to be opened when the compression piston is located at a lower dead point each time, and the first air supply valve and the second air supply valve are sequentially and alternately opened; and is

When the first air supply valve is opened, the second oil sprayer sprays oil, and when the second air supply valve is opened, the first oil sprayer sprays oil; and is

And when the compression piston moves from the top dead center to the bottom dead center every time, controlling the first air supply valve and the second air supply valve to be closed.

4. A split-cylinder cycle internal combustion engine as claimed in claim 3 wherein the compression cylinder is further provided with at least one suction valve, the control means being in signal connection with the at least one suction valve;

wherein the control device is configured to control the at least one suction valve to close when one of the first and second air supply valves is open; and is

Controlling the at least one suction valve to open when both the first and second supply valves are closed.

5. The split-cylinder cycle internal combustion engine of claim 3,

the first combustion cylinder includes a first variable timing intake valve in communication with the first air bleed valve through a first intake duct;

the second combustion cylinder includes a second variable timing intake valve in communication with the second air bleed valve through a second intake pipe;

the control device is in signal connection with both the first variable timing intake valve and the second variable timing intake valve, and the first intake pipe and the second intake pipe are configured to store gas.

6. The split-cylinder internal combustion engine of claim 5 wherein the first combustion cylinder includes a first exhaust valve and the expansion cylinder includes a first expansion valve, the first exhaust valve being in communication with the first expansion valve;

the second combustion cylinder includes a second exhaust valve, the expansion cylinder includes a second expansion valve, and the second exhaust valve is in communication with the second expansion valve;

the first exhaust valve and the first expansion valve are synchronously opened and closed, and the second exhaust valve and the second expansion valve are synchronously opened and closed; and is

The control device is in signal connection with the first exhaust valve, the second exhaust valve, the first expansion valve and the second expansion valve, and the control device is configured to:

when the first fuel injector injects fuel and the first combustion piston moves from the top dead center to the bottom dead center, controlling the first exhaust valve to be opened and the second exhaust valve to be closed;

when the second fuel injector injects fuel and the second combustion piston moves from the top dead center to the bottom dead center, the second exhaust valve is controlled to be opened, and the first exhaust valve is controlled to be closed;

and controlling the first exhaust valve and the second exhaust valve to be closed when the combustion piston moves from the top dead center to the bottom dead center.

7. The split-cylinder-cycle internal combustion engine according to claim 6,

the expansion cylinder also comprises at least one gas outlet valve, and the control device is in signal connection with the at least one gas outlet valve;

wherein the control device is configured to: controlling the at least one outlet valve to close when one of the first expansion valve and the second expansion valve is open; and is

And when the first expansion valve and the second expansion valve are both closed, controlling the at least one air outlet valve to be opened.

8. The split-cylinder cycle internal combustion engine according to any one of claims 1 to 7,

the volume of the expansion cylinder is 2-2.5 times of that of the compression cylinder; and/or

The first combustion cylinder and the second combustion cylinder have the same volume, and the compression cylinder has a volume 3 times or more the volume of the first combustion cylinder.

9. The split-cylinder cycle internal combustion engine according to any one of claims 1 to 7,

the expansion cylinder is wrapped with a heat insulation layer; and/or

The first combustion cylinder and the second combustion cylinder are arranged in a V shape.

10. The split-cylinder cycle internal combustion engine according to any one of claims 1 to 7,

the crankshaft includes a main journal and first, second, third, and fourth journals protruding from the main journal, the first journal being connected to the compression piston, the second journal being connected to the first combustion piston, the third journal being connected to the second combustion piston, and the fourth journal being connected to the expansion piston;

wherein a phase difference between the first crank journal and the second crank journal in a circumferential direction around the main journal is 180 °, a phase difference between the second crank journal and the third crank journal in the circumferential direction around the main journal is 0 °, and a phase difference between the third crank journal and the fourth crank journal in the circumferential direction around the main journal is 0 °.

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