Oil pump, engine housing, engine and working machine

Abstract

The utility model relates to the technical field of lubricating equipment, and discloses an oil pump device which comprises a pump body, the pump body comprises an engine connecting part, an input port and an output port, and the engine connecting part is suitable for being fixedly connected with the outside of an engine and can be detached; the input port is suitable for being communicated with an oil pumping channel of an engine; the output port is suitable for being communicated with an oil conveying channel of an engine. The utility model further discloses an engine shell which comprises a shell, an engine oil pump installation part is arranged on the shell, an oil outlet hole and an oil inlet hole are formed in the engine oil pump installation part, the oil outlet hole is suitable for being communicated with an oil pumping channel of an engine and an input port of an engine oil pump, and the oil inlet hole is suitable for being communicated with an oil conveying channel of the engine and an output port of the engine oil pump. The utility model further discloses an engine which comprises the engine oil pump and the engine shell. The utility model further provides an operation machine which comprises the engine so as to solve the problems that an oil pump is long in maintenance time and complex.

Description

Technical Field

[0001] The utility model relates to the technical field of lubrication equipment, in particular to an oil pump, an engine housing, an engine and an operating machine. Background Art

[0002] The oil pump in the lubrication system raises the oil to a certain pressure and then forcibly presses it onto the moving surfaces of various engine parts. Its working principle is: when the engine is working, the driving gear on the camshaft drives the transmission gear of the oil pump, causing the driving gear fixed on the driving gear shaft to rotate, thereby driving the driven gear to rotate in the opposite direction, and sending the oil from the oil inlet chamber along the tooth gap and the pump wall to the oil outlet chamber. A low pressure is formed at the oil inlet chamber, generating suction, which sucks the oil in the oil pan into the oil chamber. Due to the continuous rotation of the driving and driven gears, the oil is continuously pressed to the required parts.

[0003] The engine will produce wear during operation, and metal particles will be mixed in the engine oil. The metal particles will be transported to the parts of the engine that need lubrication through the oil pump. As the metal particles mixed in the lubricating oil increase, the metal particles will cause damage to the internal components of the oil pump during the pumping process. Since the oil pump is usually installed inside the engine, the engine needs to be disassembled when repairing or replacing the oil pump. The repair process is complicated and the repair time is long. Summary of the invention

[0004] In view of this, the utility model provides an oil pump, an engine housing, an engine and an operating machine to solve the problem that the oil pump maintenance takes a long time and is complicated.

[0005] In a first aspect, the utility model provides an oil pump device, comprising a pump body, wherein the pump body comprises: an engine connecting portion, an input port and an output port, wherein the engine connecting portion is suitable for being fixedly connected to the outside of the engine and is removable; the input port is suitable for being connected to an oil extraction passage of the engine to extract lubricating oil from an oil pan of the engine; and the output port is suitable for being connected to an oil delivery passage of the engine to deliver lubricating oil to a part to be lubricated in the engine.

[0006] Beneficial effect: By detachably mounting the pump body of the oil pump on the outside of the engine and connecting it with the oil extraction channel and the oil delivery channel inside the engine, it is not only possible to deliver lubricating oil to the parts inside the engine that need lubrication, but also when the oil pump is damaged, the oil pump can be directly removed and replaced without disassembling the engine, so that the oil pump can be repaired or replaced quickly and easily.

[0007] In an optional embodiment, a servo motor is further included, which is drivingly connected to the rotating shaft of the pump body. The servo motor is suitable for being electrically connected to the control center of the engine to receive an operating signal generated by the control center according to the speed and load of the camshaft, and operate according to the operating signal.

[0008] Beneficial effects: By driving the oil pump with a servo motor, the oil pump can adjust the lubricating oil delivery amount according to the engine speed and load, which can improve the lubrication effect on various engine components and extend their service life. It can also improve the technical problem that the oil pump only changes the lubricating oil delivery amount according to the engine speed and cannot adjust the lubricating oil delivery amount according to the engine load conditions, thereby causing poor lubrication of various engine components.

[0009] In an optional implementation, the pump body is a vane pump.

[0010] Beneficial effect: The adjustment of the oil supply of the vane pump is more accurate as the driving speed is adjusted, and the technology is mature, which can reduce costs.

[0011] In an optional embodiment, the vane pump includes an inner rotor and an eccentric wheel, the inner rotor is provided with a drive groove; the eccentric wheel is located in the drive groove, the eccentric wheel is used for transmission connection with an external rotating device, the distance between the symmetric center axis of the inner rotor and the rotation axis of the eccentric wheel is the eccentricity of the inner rotor, and the driving radius of the eccentric wheel is greater than the eccentricity of the inner rotor.

[0012] Beneficial effect: The eccentric wheel is used to rotationally frictionally drive the wall surface of the driving groove of the inner rotor, and the driving radius of the eccentric wheel is larger than the eccentricity of the inner rotor, so that the inner rotor revolves around the rotation axis of the eccentric wheel and rotates around the symmetric center axis of the inner rotor to pump lubricating oil, thereby realizing global variable displacement control of the oil supply of the oil pump.

[0013] In an optional embodiment, the rotation axis of the eccentric wheel coincides with the symmetry center of the working chamber where the inner rotor is located.

[0014] Beneficial effect: The rotation axis of the eccentric wheel coincides with the symmetry center of the working chamber, which can facilitate the adjustment design of the oil supply of the oil pump.

[0015] In an optional embodiment, it further includes a plurality of blades, a plurality of accommodating grooves are radially arranged on the outer circumferential surface of the inner rotor, the plurality of blades are respectively arranged in the plurality of accommodating grooves for reciprocating sliding, the blades are sealed and slidably connected to the accommodating grooves, the bottom of the accommodating grooves is connected to an air accommodating cavity, and / or a return spring is arranged between the bottom of the accommodating groove and the blades.

[0016] Beneficial effects: the blades are sealed and slidably connected to the accommodating grooves, and an air chamber is provided at the bottom of the accommodating grooves, so that a sealed space can be formed between the blades and the bottom of the accommodating grooves. Compressed air is formed in the air chamber during the sliding of the blades into the accommodating grooves, thereby providing power for the blades to move away from the symmetry center of the inner rotor; a return spring is provided between the bottom of the accommodating groove and the blades, which can also provide power for the blades to move away from the symmetry center of the inner rotor; of course, the combination of the two can increase the intensity of the power, increase the contact pressure between the blades and the working chamber, and thereby improve the sealing performance.

[0017] In the second aspect, the utility model also provides an engine casing, including an outer shell, on which an oil pump mounting portion is provided, and on which an oil outlet hole and an oil inlet hole are provided, the oil outlet hole being suitable for connecting the oil extraction passage of the engine with the input port of the oil pump, and the oil inlet hole being suitable for connecting the oil delivery passage of the engine with the output port of the oil pump.

[0018] Beneficial effect: Since the engine housing can be used in conjunction with the above-mentioned oil pump and has the same effect as the above-mentioned oil pump, it will not be repeated here.

[0019] In an optional embodiment, it also includes an oil extraction pipeline and an oil delivery pipeline, the two ends of the oil extraction pipeline are respectively suitable for communicating with the oil outlet and the space inside the oil pan of the engine, and the two ends of the oil delivery pipeline are respectively suitable for communicating with the oil outlet and the part to be lubricated in the engine, the oil extraction pipeline is the oil delivery channel of the engine, and the oil delivery pipeline is the oil delivery channel of the engine.

[0020] Beneficial effect: By arranging the oil extraction pipeline and the oil delivery pipeline in the engine casing, the design and assembly of the engine are facilitated.

[0021] In a third aspect, the utility model further provides an engine, comprising the oil pump as described in the first aspect and the engine housing as described in the second aspect.

[0022] Beneficial effect: Since the engine has the above-mentioned oil pump and engine housing, it has the same effect as the above-mentioned oil pump and will not be described in detail here.

[0023] In a fourth aspect, the utility model further provides a working machine, comprising the engine as described in the third aspect.

[0024] Beneficial effects: Since the operating machine has the above-mentioned engine, it has the same effects as the above-mentioned engine and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic structural diagram of an oil pump according to an embodiment of the utility model;

[0027] Figure 2 Another structural schematic diagram of an oil pump according to an embodiment of the utility model;

[0028] Figure 3 Another structural schematic diagram of an oil pump according to an embodiment of the utility model;

[0029] Figure 4 for Figure 3 Cross-section at AA in the middle;

[0030] Figure 5 A front view of an oil pump according to an embodiment of the utility model;

[0031] Figure 6 for Figure 5 Cross-section view at the middle BB.

[0032] Description of reference numerals:

[0033] 1. Pump body, 2. Servo motor, 3. Body seal, 4. Mounting seal, 5. Positioning column;

[0034] 101. Pump casing, 102. Inner rotor, 103. Blades, 104. Eccentric wheel, 105. Working chamber, 106. Oil inlet chamber, 107. Oil outlet chamber, 108. Accommodating groove, 109. Infusion chamber, 110. Air chamber, 111. Driving groove. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0036] In the related art, the engine will produce wear during operation, forming metal particles mixed in the engine oil. The metal particles will be transported to the parts of the engine that need lubrication through the oil pump. As the metal particles mixed in the lubricating oil increase, the metal particles will cause damage to the internal components of the oil pump during the pumping process. Since the oil pump is usually installed inside the engine, the engine needs to be disassembled when repairing or replacing the oil pump. The repair process is complicated and the repair time is long.

[0037] Combine the following Figures 1 to 6 , describing an embodiment of the utility model.

[0038] According to an embodiment of the present utility model, in a first aspect, an oil pump is provided, such as Figures 1-2 As shown, the pump body 1 includes: an engine connecting part, an input port and an output port, the engine connecting part is suitable for being fixedly connected to the outside of the engine and can be disassembled; the input port is suitable for being connected to the oil extraction channel of the engine to extract the lubricating oil in the oil pan of the engine; the output port is suitable for being connected to the oil delivery channel of the engine to deliver the lubricating oil to the part to be lubricated in the engine.

[0039] In the above embodiment, the pump body 1 of the oil pump is detachably mounted on the outside of the engine and connected with the oil extraction channel and the oil delivery channel inside the engine, so that not only the lubricating oil can be delivered to the parts inside the engine that need lubrication, but also when the oil pump is damaged, the oil pump can be directly removed and replaced without disassembling the engine, so that the oil pump can be repaired or replaced quickly and easily.

[0040] In some embodiments not shown, Figures 1-2 As shown, the pump body 1 is screwed to the engine casing by bolts; a positioning column 5 can be provided on the pump body 1 to achieve installation and positioning with the engine casing; at the same time, a body seal 3 is provided between the matching surface of the pump body 1 and the engine to prevent oil leakage and gas leakage; the pump body 1 is driven by a driving motor fixed to the engine, or is connected to the engine crankshaft transmission for driving (such as by one of the methods such as belts, chains and gears).

[0041] In one embodiment, Figure 1 , 5 As shown in Figure 6, the oil pump also includes a servo motor 2, which is connected to the rotating shaft of the pump body 1 by transmission. The servo motor 2 is suitable for being electrically connected to the control center of the engine to receive an operating signal generated by the control center according to the speed and load of the camshaft, and operates according to the operating signal.

[0042] During the specific implementation process, it is necessary to set a speed sensor and a load sensor at the crankshaft position of the engine. The speed sensor and the load sensor transmit the real-time speed and real-time load data signals of the engine to the engine control center, such as the engine operating condition processor ECU. The engine control center takes the real-time speed signal and real-time load signal of the engine crankshaft as input, outputs the speed of the oil pump according to its built-in oil pump speed generation program, and sends it to the servo motor 2 to control the speed of the servo motor 2.

[0043] The specific oil pump speed generation program can set the corresponding oil pump speed under different loads in various speed ranges of the engine, such as ① when the engine crankshaft is 1000 rpm to 1500 rpm: the crankshaft load is 20% to 30%, the oil pump speed is 100 rpm; when the crankshaft load is 30% to 40%, the oil pump speed is 150 rpm; ...;

[0044] ② When the engine crankshaft is at 1500 rpm to 2000 rpm: when the crankshaft load is 20% to 30%, the oil pump speed is 200 rpm; when the crankshaft load is 30% to 40%, the oil pump speed is 250 rpm; ...;

[0045] ……;

[0046] ⑥ When the engine crankshaft is at 4000 rpm ~ 4500 rpm: the crankshaft load is between 20% and 30%, and the oil pump speed is 400 rpm; when the crankshaft load is between 30% and 40%, the oil pump speed is 500 rpm;…

[0047] It is worth noting that all the numerical values ​​in the above oil pump speed generation program are fictitious values, which are constructed to illustrate the principle of the oil pump speed generation program. Designers can make adaptive adjustments according to different working conditions of different engines.

[0048] In this implementation, the oil pump is driven by the servo motor 2, so that the oil pump can adjust the lubricating oil delivery amount according to the engine speed and load, thereby improving the lubrication effect on various engine components and extending their service life. It can also improve the technical problem that the oil pump only adjusts according to the engine speed to change the lubricating oil delivery amount, and cannot adjust the lubricating oil delivery amount according to the engine load conditions, thereby causing poor lubrication of various engine components.

[0049] In one embodiment, the pump body 1 is a vane pump, and the specific vane pump may be a variable volume pump or the like.

[0050] In some embodiments not shown, the pump body 1 may also be a gear pump or other pump types.

[0051] In this implementation, the adjustment of the oil supply of the vane pump is more accurate as the driving speed is adjusted, and the technology is mature and the market price is cheap, which can reduce costs.

[0052] In one embodiment, Figures 2 to 6 As shown, the vane pump includes an inner rotor 102 and an eccentric wheel 104. A driving groove 111 is provided on the inner rotor 102. The eccentric wheel 104 is located in the driving groove 111. The eccentric wheel 104 is used for transmission connection with an external rotating device. The distance between the symmetric center axis of the inner rotor 102 and the rotation axis of the eccentric wheel 104 is the eccentricity of the inner rotor 102. The driving radius of the eccentric wheel 104 is greater than the eccentricity of the inner rotor 102.

[0053] Specifically, the vane pump includes a pump housing 101, an inner rotor 102, an eccentric wheel 104 and a plurality of vanes 103. The pump housing 101 is provided with a working chamber 105. The pump housing 101 is provided with an oil inlet chamber 106 for communicating with an oil outlet hole on the engine and an oil outlet chamber 107 for communicating with the oil inlet hole on the engine; the inner rotor 102 is rotatably arranged in the working chamber 105, a plurality of accommodating grooves 108 are radially arranged on the outer ring surface of the inner rotor 102, and a driving groove 111 is arranged on the inner rotor 102; a plurality of vanes 103 are respectively arranged in the plurality of accommodating grooves 108 for reciprocating sliding, and the vanes 103 correspond to the accommodating grooves 108 one by one, and the plurality of vanes 103 can automatically The inner rotor 102 moves toward the inner wall surface of the working chamber 105 and makes sliding contact with the inner ring wall surface of the working chamber 105. The inner rotor 102, the pump housing 101 and the plurality of blades 103 form a plurality of infusion chambers 109, wherein a part of the plurality of infusion chambers 109 are communicated with the oil inlet chamber 106, and another part of the plurality of infusion chambers 109 are communicated with the oil storage chamber; the eccentric wheel 104 is located in the driving groove 111 of the inner rotor 102, and the eccentric wheel 104 is used for transmission connection with an external rotating device, and the distance between the symmetric center axis of the inner rotor 102 and the rotation axis of the eccentric wheel 104 is the eccentric distance of the inner rotor 102, and the driving radius of the eccentric wheel 104 is greater than the eccentric distance of the inner rotor 102.

[0054] It should be noted that the shape of the working chamber 105 can be one of other shapes such as a circle, an ellipse, etc., and the outer contour surface of the inner rotor 102 can be one of other shapes such as a circle, an ellipse, etc. In the present utility model, as long as the inner rotor 102 and the working chamber 105 can cooperate to achieve oil pumping, the shape can be selected according to actual conditions or design requirements.

[0055] Specifically, Figure 4 As shown, the eccentric wheel 104 is elliptical, and its rotating axis is close to one side of its long radius. Of course, the eccentric wheel 104 can also be replaced by a slender driving arm, such as a long rod + cylinder, etc. The cylinder is used for sliding friction with the inner ring surface of the inner rotor 102, and one end of the long rod is the rotating axis, which is connected to the external driving motor for transmission.

[0056] During the specific implementation process, the rotating shaft of the servo motor 2 passes through the pump housing 101 and is spline-bonded to the eccentric wheel 104. The servo motor 2 is threadedly connected to the pump housing 101 by bolts. An installation seal 4 is provided between the servo motor 2 and the pump housing 101 to seal and prevent oil leakage and gas exchange, etc.; the servo motor 2 drives the eccentric wheel 104 to rotate, and the eccentric wheel 104 drives the wall surface of the driving groove 111 of the inner rotor 102 to rotate and frictionally drive, and the driving radius of the eccentric wheel 104 is greater than the eccentricity of the inner rotor 102, so that the inner rotor 102 revolves around the rotation axis of the eccentric wheel 104 and rotates around the symmetric center axis of the inner rotor 102, thereby realizing the volume change of multiple infusion chambers 109, and then realizing the global variable displacement control of the oil supply of the oil pump.

[0057] In a specific embodiment, the rotation axis of the eccentric wheel 104 coincides with the symmetry center of the working chamber 105 where the inner rotor 102 is located.

[0058] In this embodiment, the rotation axis of the eccentric wheel 104 coincides with the symmetry center of the working chamber 105. During the design and development process, it is convenient for researchers to adjust the relative positions of the eccentric wheel 104 and the inner rotor 102, thereby facilitating the design and adjustment of the oil supply of the oil pump.

[0059] In one embodiment, Figure 4 As shown, the blade 103 is sealingly and slidably connected to the receiving groove 108 , the bottom of the receiving groove 108 is connected to an air receiving chamber 110 , and / or a return spring is provided between the bottom of the receiving groove 108 and the blade 103 .

[0060] In this embodiment, the blade 103 is sealed and slidably connected to the accommodating groove 108, and the bottom of the accommodating groove 108 is connected to an air accommodating chamber 110, which can form a sealed space between the blade 103 and the bottom of the accommodating groove 108, and compressed air is formed in the air accommodating groove during the sliding process of the blade 103 into the accommodating groove 108, thereby providing power for the blade 103 to move away from the symmetry center of the inner rotor 102; a return spring is provided between the bottom of the accommodating groove 108 and the blade 103, which can also provide power for the blade 103 to move away from the symmetry center of the inner rotor 102; of course, the combination of the two can increase the intensity of the power, increase the contact pressure between the blade 103 and the working chamber 105, and thus improve the sealing performance.

[0061] In some embodiments not shown, the reset spring may be replaced by a component with a telescopic function, such as a pneumatic telescopic rod, elastic rubber, etc., which may also realize automatic reset of the blade 103 .

[0062] In the second aspect, the utility model also provides an engine casing, including an outer shell, on which an oil pump mounting portion is arranged, and the oil pump mounting portion is provided with an oil outlet hole and an oil inlet hole, the oil outlet hole is suitable for connecting the oil extraction channel of the engine with the input port of the oil pump, and the oil inlet hole is suitable for connecting the oil delivery channel of the engine with the output port of the oil pump.

[0063] Specifically, the mounting portion is a mounting platform, which matches a corresponding portion of the oil pump.

[0064] In this embodiment, since the engine housing can be used in conjunction with the above-mentioned oil pump and has the same effect as the above-mentioned oil pump, it will not be described in detail here.

[0065] In one embodiment, it also includes an oil extraction pipeline and an oil delivery pipeline. The two ends of the oil extraction pipeline are respectively suitable for communicating with the oil outlet and the space inside the oil pan of the engine, and the two ends of the oil delivery pipeline are respectively suitable for communicating with the oil outlet and the part to be lubricated in the engine. The oil extraction pipeline is the oil delivery channel of the engine, and the oil delivery pipeline is the oil delivery channel of the engine.

[0066] In this embodiment, the design and assembly of the engine are facilitated by arranging the oil extraction pipeline and the oil delivery pipeline in the engine housing.

[0067] In a third aspect, the utility model further provides an engine, comprising the oil pump provided in the embodiment of the first aspect and the engine housing provided in the embodiment of the second aspect, and the engine may be a gasoline engine, a diesel engine, a natural gas engine, or the like.

[0068] In this embodiment, because the engine has the above-mentioned oil pump and engine housing, it has the same effect as the above-mentioned oil pump and will not be described in detail here.

[0069] In a fourth aspect, the utility model further provides an operating machine, including the engine provided in the third aspect, wherein the operating machine can be a means of transportation such as a car, a bus, an airplane, or a functional mechanical equipment such as an excavator and a bulldozer.

[0070] In this embodiment, since the working machine has the above-mentioned engine, it has the same effect as the above-mentioned engine and will not be described in detail here.

[0071] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An oil pump, characterized in that: The invention comprises a pump body (1), wherein the pump body (1) comprises: The engine connection part is suitable for being fixedly connected to the outside of the engine and can be disassembled; An input port, adapted to communicate with an oil extraction passage of the engine to extract lubricating oil from an oil pan of the engine; The output port is adapted to communicate with the oil delivery channel of the engine so as to deliver lubricating oil to the part to be lubricated in the engine; It also includes a servo motor (2), which is drivingly connected to the rotating shaft of the pump body (1), and the servo motor (2) is suitable for being electrically connected to the control center of the engine to receive an operating signal generated by the control center according to the rotation speed and load of the camshaft, and operates according to the operating signal.

2. The oil pump according to claim 1, characterized in that: The pump body (1) is a vane pump.

3. The oil pump according to claim 2, characterized in that: The vane pump comprises: an inner rotor (102), wherein a driving slot (111) is provided on the inner rotor (102); and An eccentric wheel (104) is located in the driving groove (111). The eccentric wheel (104) is used for transmission connection with an external rotating device. The distance between the symmetric center axis of the inner rotor (102) and the rotation axis of the eccentric wheel (104) is the eccentricity of the inner rotor (102). The driving radius of the eccentric wheel (104) is greater than the eccentricity of the inner rotor (102).

4. The oil pump according to claim 3, characterized in that: The rotation axis of the eccentric wheel (104) coincides with the symmetry center of the working chamber (105) where the inner rotor (102) is located.

5. The oil pump according to claim 3, characterized in that: It also includes a plurality of blades (103), a plurality of receiving grooves (108) are radially arranged on the outer peripheral surface of the inner rotor (102), the plurality of blades (103) are respectively arranged in the plurality of receiving grooves (108) for reciprocating sliding, the blades (103) are sealed and slidably connected to the receiving grooves (108), the bottom of the receiving groove (108) is connected to an air receiving cavity (110), and / or a return spring is arranged between the bottom of the receiving groove (108) and the blade (103).

6. An engine housing, suitable for use with the oil pump according to any one of claims 1 to 5, characterized in that: It comprises a shell, on which an oil pump mounting portion is arranged, on which an oil outlet hole and an oil inlet hole are arranged, the oil outlet hole is suitable for connecting an oil extraction passage of the engine with an input port of the oil pump, and the oil inlet hole is suitable for connecting an oil delivery passage of the engine with an output port of the oil pump.

7. The engine housing according to claim 6, characterized in that: It also includes an oil extraction pipeline and an oil delivery pipeline, the two ends of the oil extraction pipeline are respectively suitable for communicating with the oil outlet and the space inside the oil pan of the engine, and the two ends of the oil delivery pipeline are respectively suitable for communicating with the oil outlet and the part to be lubricated in the engine, the oil extraction pipeline is the oil delivery channel of the engine, and the oil delivery pipeline is the oil delivery channel of the engine.

8. An engine, characterized in that: The invention comprises an oil pump as claimed in any one of claims 1 to 5 and an engine housing as claimed in any one of claims 6 to 7.

9. A working machine, characterized in that: Comprising an engine as claimed in claim 8.

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