CN116291839A

CN116291839A - Oil-cooled four-stroke engine for powered parachute

Info

Publication number: CN116291839A
Application number: CN202211606422.4A
Authority: CN
Inventors: 温文贤
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-12-15
Filing date: 2022-12-14
Publication date: 2023-06-23
Also published as: TW202325613A; TWI790860B

Abstract

An oil-cooled four-stroke engine for a power parachute comprises an engine body, a parachute fixing frame, an oil cooler and an oil cooling pipe assembly, wherein an engine oil channel is arranged in the engine body, the parachute fixing frame is arranged on one side of the engine body, the oil cooler is fixed on the parachute fixing frame, and the oil cooling pipe assembly is used for communicating the oil cooler with the engine oil channel of the engine body; therefore, the oil cooled by the oil cooler can be led into the engine body by the oil cooling pipe fitting group, and the effects of cooling and lubricating are achieved, so that the weight of the oil cooled four-stroke engine is greatly reduced, and the load and the fuel consumption of users are reduced.

Description

Oil-cooled four-stroke engine for powered parachute

Technical Field

The present invention relates to a four-stroke engine, and more particularly to a four-stroke engine for a powered parachute.

Background

The power flight parachute is a flight parachute matched with a propeller engine, and can achieve the characteristic of lasting flight by the thrust provided by the propeller engine, so that the power flight parachute is widely applied to the field of aviation motion.

Referring to fig. 7, a water-cooled four-stroke engine 60 for a propeller engine is disclosed, wherein the air displacement of the water-cooled four-stroke engine 60 is 250c, the engine comprises a water tank 61, an engine body 62, a cold water pipe 63 and a hot water pipe 64, wherein the water tank 61 is disposed and fixed on one side of the engine body 62, and comprises a cooling water outlet 611 and a cooling water inlet 612, the cooling water outlet 611 and the cooling water inlet 612 of the water tank 61 are respectively connected with the cold water pipe 63 and the hot water pipe 64, the cold water pipe 63 is connected to the engine body 62 for allowing a cooling water of the water tank 61 to enter and cool the engine body 62, and the cooling water leaves the engine body 62 after absorbing the heat generated by the engine body 62 and flows back to the water tank 61 through the hot water pipe 64. In the water-cooled four-stroke engine 60, the engine body 62 is required to be increased in thickness to form a water passage (not shown) for the cooling water to flow, so that the weight of the engine body 62 including an exhaust pipe shown in fig. 7 is up to 18 kg, and the weight of the water tank 61, the cold water pipe 63, the hot water pipe 64 and the cooling water are added to make the total weight of the water-cooled four-stroke engine 60 up to 23 to 25 kg.

As can be seen from the above description, the water-cooled four-stroke engine is a power source of the power parachute, but for long-distance flight, the engine body must be maintained within a certain temperature range, while the four-stroke engine for the conventional power parachute adopts a water-cooled heat dissipation method, i.e. the water tank must be hung on the engine body, and the water tank and the cooling water significantly increase the volume and weight of the four-stroke engine, increase the weight burden of the user when the user starts and descends and increase the fuel consumption during flight, so that further improvement is necessary.

Disclosure of Invention

In view of the drawbacks of the weight increase of the users and the fuel consumption increase caused by the excessive weight of the water-cooled four-stroke engine, the main object of the present invention is to provide an oil-cooled four-stroke engine for a powered parachute.

In order to achieve the above object, the present invention provides a main technical means for making the above oil-cooled four-stroke engine for a powered parachute comprising:

the engine body at least comprises a crankcase, a cylinder cover and an engine oil channel, wherein the engine oil channel penetrates through one side wall of the crankcase, the cylinder and the cylinder cover and is communicated with a camshaft chamber of the cylinder cover;

the flying umbrella fixing frame is arranged at the front side of the engine body;

the engine oil cooler is arranged on one side of the flying umbrella fixing frame; and

an oil cooling pipe set connected to the oil cooler and the engine oil channel of the engine body.

As can be seen from the above description, the oil-cooled four-stroke engine for a power parachute of the present invention forms the oil passage inside the engine body, and externally hangs the oil cooler on one side of the engine body, and then uses the oil-cooled pipe assembly to connect the oil passage and the oil cooler, the oil-cooled pipe assembly can guide the engine oil cooled by the oil cooler into the engine body, and the engine oil can absorb the excessive heat generated by the fuel oil combusted in the cylinder through the crankcase, the cylinder and the cylinder head of the engine body via the oil passage, and also can lubricate the internal components of the engine body, so that the oil-cooled four-stroke engine of the present invention does not need to use an externally hung cooling water tank, thereby achieving the goal of engine weight saving, and reducing the weight burden of the user and the consumption of the fuel oil for flying when the user starts and descends.

The invention will now be described in more detail with reference to the drawings and specific examples, which are not intended to limit the invention thereto.

Drawings

Fig. 1: a schematic of a powered parachute employing the oil-cooled four-stroke engine of the present invention.

Fig. 2: the invention relates to a perspective view of an oil-cooled four-stroke engine.

Fig. 3: the invention provides a three-dimensional exploded view of an oil-cooled four-stroke engine.

Fig. 4A: the invention provides a perspective view of a front crankcase of an oil-cooled four-stroke engine.

Fig. 4B: a cross-sectional view of the line A-A of fig. 4A.

Fig. 5A: the invention provides a perspective view of a rear crankcase of an oil-cooled four-stroke engine.

Fig. 5B: the invention provides a perspective view of a rear crankcase of an oil-cooled four-stroke engine.

Fig. 5C: a cross-sectional view of the B-B cut line of FIG. 5A.

Fig. 6A: fig. 2 is a partial perspective view.

Fig. 6B: the invention relates to a partial rear perspective exploded view of an oil-cooled four-stroke engine.

Fig. 7: a perspective view of a conventional water-cooled four-stroke engine.

Wherein, the reference numerals:

1 oil-cooled four-stroke engine 2 oil tank

3 engine frame 4 back type flying umbrella

5 propeller 10 engine body

11 crankcase 110 oil tank

111 front crankcase 112 rear crankcase

113 crank chamber 114 pride shaft fixing column

115 propeller pride shaft 116 propeller driving wheel

117 crankshaft assembly 118 belt

119 piston 12 cylinder

121 cavity 13 cylinder head

131 camshaft chamber 132 timing inner sprocket chamber

133 camshaft 134 combustion chamber

135 timing chain 136 exhaust pipe

14 oil passage 141 oil outlet

142 oil inlet 143 first passage

144 sub-channel 145 return channel

146 second channel 147 engine oil pump

148 inner channel 15 cover plate

151 heat engine oil outlet 152 cold engine oil inlet

16, a screwing groove 17, a stud

20, a flying umbrella fixing frame 21, a flying umbrella fixing arm

22, cross arm 30, engine oil cooler

31 cooler body 311 heat engine oil inlet

312 Cold machine oil outlet 32, front fixing piece

Rear fixing piece 40 oil-cooled pipe assembly

41 heat engine oil pipe 42 cooling machine oil pipe

60 water-cooled four-stroke engine 61 water tank

611 cooling water outlet 612 cooling water inlet

62 engine body 63, cold water pipe

64 Hot water pipe

Detailed Description

The structural and operational principles of the present invention are described in detail below with reference to the accompanying drawings:

referring first to fig. 1, a power parachute using an oil-cooled four-stroke engine 1 of the present invention includes a fuel tank 2, an engine frame 3, a back parachute 4 (canopy not shown) and a propeller 5, wherein the fuel tank 2 is disposed on the bottom surface of the oil-cooled four-stroke engine 1 to send a fuel into the oil-cooled four-stroke engine 1, the propeller 5 is connected to the rear side of the oil-cooled four-stroke engine 1, and the propeller 5 provides a thrust to the power parachute. The oil-cooled four-stroke engine 1 and the oil tank 2 are fixed together in the engine frame 3, and the back-type parachute 4 is fastened to the front side of the engine frame 3 for a person to carry the power parachute.

Referring to fig. 2 and 3, the oil-cooled four-stroke engine 1 comprises an engine body 10, an air-parachute holder 20, an oil cooler 30 and an oil-cooling pipe assembly 40, wherein the engine body 10 comprises a crankcase 11, a cylinder 12, a cylinder head 13 and an oil passage 14, and the oil passage 14 penetrates a sidewall of the crankcase 11, the cylinder 12 and the cylinder head 13 and is communicated with a camshaft chamber 131 inside the cylinder head 13.

As will be further described below, referring to fig. 2 and 3, in this embodiment, the crankcase 11 of the engine body 10 further includes a sump 110, a front crankcase 111, a rear crankcase 112, and a crank chamber 113, wherein the sump 110 extends downward from the bottom of the crankcase 11, the front and

rear crankcases

111, 112 are combined with each other, the crank chamber 113 is formed between the front crankcase 111 and the rear crankcase 112, and the crank chamber 113 is in communication with the sump 110; as further shown in fig. 4A and 4B, an oil outlet 141 and an oil inlet 142 are formed at the front side of the front crankcase 111.

Referring to fig. 2, a cover plate 15 is fixed on the outer side of the front crankcase 111 of the engine body 10, the cover plate 15 is located between the front crankcase 111 of the engine body 10 and the flying umbrella holder 20, and the cover plate 15 includes a heat engine oil outlet 151 and a cold engine oil inlet 152, as further shown in fig. 6A, wherein the heat engine oil outlet 151 is in communication with the engine oil outlet 141 of the front crankcase 111, and the cold engine oil inlet 152 is in communication with the engine oil inlet 142 of the front crankcase 111.

Referring to fig. 3, a propeller shaft fixing post 114 extends upward from the outer side of the rear crankcase 112 of the engine body 10, wherein the propeller shaft fixing post 114 is used for a propeller shaft 115 to pass through and fix, the propeller shaft 115 is connected with a propeller driving wheel 116 located at the rear side of the rear crankcase 112, and the propeller driving wheel 116 is connected with the propeller 5 as shown in fig. 1; as shown in fig. 5A and 5B, the rear side and the front side of the common shaft fixing post 114 are integrally formed with a plurality of longitudinal reinforcing arms 114B, and a plurality of transverse reinforcing ribs 114a are further formed between the adjacent longitudinal reinforcing arms 114B, respectively, to reinforce the common shaft fixing post 114, so as to reduce the stress concentration of the common shaft fixing post 114 of the rear crankcase 112 caused when the propeller 5 of the power flying umbrella is used; in the present embodiment, three longitudinal reinforcing arms 114b are respectively formed on the front side and the rear side of the common axle fixing post 114, and two transverse reinforcing ribs 114a are formed on the rear side of the common axle fixing post 114, but not limited thereto.

In this embodiment, as shown in fig. 3, a crankshaft assembly 117 is disposed in the crank chamber 113 of the crankcase 11, and two ends of the crankshaft assembly 117 protrude from the front side of the front crankcase 111 and the rear side of the rear crankcase 112, respectively, and one end of the crankshaft assembly 117 penetrating out of the rear side of the rear crankcase 112 is connected to the propeller driving wheel 116 of the rear crankcase 112 through a belt 118, so as to transmit power to the propeller driving wheel 116 through the belt 118, and further transmit power to the propeller 5 of the power parachute shown in fig. 1.

As shown in fig. 2, the cylinder 12 of the engine body 10 is fixed to an outer side of the crankcase 11; in the present embodiment, the cylinder 12 is fixed at a position above the right side of the crankcase 11 so as to be obliquely fixed to the crankcase 11; as further shown in FIG. 3, the cylinder 12 includes a cavity 121, the cavity 121 extending through the cylinder 12 to mate with a piston 119 disposed on the crankshaft assembly 117.

As shown in fig. 2, the cylinder head 13 of the engine body 10 is fixed to the cylinder 12, and as further shown in fig. 3 and 6A, the cylinder head 13 includes a combustion chamber 134, and the combustion chamber 134 is intermittently communicated with the cavity 121 of the cylinder 12 as the piston 119 moves; in this embodiment, referring to fig. 3, a plurality of screw grooves 16 are correspondingly formed between the cylinder 12 and the cylinder head 13 on the outer side of the crankcase 11 for a plurality of studs 17 to pass through and fix. The camshaft chamber 131 of the cylinder head 13 is provided with a camshaft 133, two valve rocker arms, two intake valves and two exhaust valves (the components are existing components of the engine and are omitted for brevity), the cylinder head 13 comprises a timing inner sprocket chamber 132, the timing inner sprocket chamber 132 is positioned behind the camshaft chamber 131 and is communicated with the camshaft chamber 131, and further penetrates through the rear side of the cylinder 12 and the rear crankcase 112 of the crankcase 11 to be communicated with the sump 110 and the crank chamber 113, wherein the timing inner sprocket chamber 132 comprises a timing chain 135, the timing chain 135 connects the camshaft 133 penetrating out of the camshaft chamber 131 and penetrating into the timing inner sprocket chamber 132 with the crank assembly 117 positioned in the rear crankcase 112, and the timing chain 135 transmits the power of the crank assembly 117 to the camshaft 133 so as to control the opening and closing sequence of the intake and exhaust valves by using the valve rocker arms connected with the camshaft 133; in this embodiment, an exhaust pipe 136 is connected to one side of the cylinder head 13 corresponding to the exhaust ports to exhaust an exhaust gas generated by the combustion chamber 134 out of the engine body 10.

Referring to fig. 5C and 6A, in the embodiment, the engine oil channel 14 includes a first channel 143, a sub-channel 144, a return channel 145 and a second channel 146; as shown in fig. 6A, the first passage 143 communicates with the oil inlet 142 on the front side of the front crankcase 111 and penetrates the front crankcase 111, the cylinder 12, and the side wall of the cylinder head 13; referring to fig. 4A and 4B, a portion of the first passage 143 corresponding to the front crankcase 111 is formed sequentially on the front side of the front crankcase 111, upward, backward, outward, and one of the screw grooves 16 for connecting to a portion of the first passage 143 corresponding to the side wall of the cylinder 12; in this embodiment, as shown in fig. 6A, the portion of the first channel 143 corresponding to the cylinder 12 and the cylinder head 13 may be the threaded slot 16 through which a stud 17 passes, so that no additional formation is necessary; as also shown in fig. 6B, the portion of the first passage 143 corresponding to the cylinder head 13 includes an inner passage 148, and the first passage 143 communicates with the camshaft chamber 131 through the inner passage 148.

As shown in fig. 4B, the sub-passage 144 of the above-mentioned oil passage is formed in the front crankcase 111 to communicate with a portion of the first passage 143 corresponding to the front crankcase 111 and the crank chamber 113; in the present embodiment, the inner diameter of the sub-passage 144 is smaller than the inner diameter of the first passage 143 of the oil passage 14, but not limited thereto.

As shown in fig. 5C, the return passage 145 of the above-mentioned oil passage is formed in the rear crankcase 112 to communicate the timing inner sprocket chamber 132 with the oil tank 110.

As shown in fig. 6A, the second passage 146 of the above-mentioned oil passage is communicated with the oil outlet 141 of the front crankcase 111 and formed in the front crankcase 111 to communicate with the oil tank 110 of the crankcase 11; in this embodiment, the oil passage 14 further comprises an oil pump 147, and the oil pump 147 is fixed in the front crankcase 111 and connected in series between the second passage 146 and the oil tank 110; as further shown in fig. 3, the oil pump 147 is connected to the crank assembly 117 inside the crankcase 11 by a chain, so that the oil pump 147 uses the power of the crank assembly 117 to convey the oil in the oil tank 110 into the second passage 146 of the oil passage 14.

As shown in fig. 3, the parachute fixing frame 20 of the oil-cooled four-stroke engine 1 is disposed at the front side of the engine body 10, and forms a plurality of parachute fixing arms 21, one side of the parachute fixing frame 20 forms a cross arm 22 and is connected with the parachute fixing arms 21 at the side, wherein the parachute fixing arms 21 are used for fixing the oil-cooled four-stroke engine 1 to the engine frame 3 of the power parachute, in this embodiment, the parachute fixing frame 20 has four parachute fixing arms 21, but not limited thereto, and the cross arm 22 formed at one side of the parachute fixing frame 20 is connected with the two parachute fixing arms 21 at the side for fixing the oil cooler 30.

As shown in fig. 2, the oil cooler 30 of the oil-cooled four-stroke engine 1 is disposed at one side of the parachute mount 20 and comprises a cooler body 31, a front fixing piece 32 and a rear fixing piece 33, wherein the cooler body 31 comprises a heat engine oil inlet 311 and a cold engine oil outlet 312; as shown in fig. 2, in the present embodiment, the front fixing piece 32 and the rear fixing piece 33 are fixed to the cross arm 22 of the parachute fixing frame together, and the oil cooler 30 is sandwiched between the front fixing piece 32 and the rear fixing piece 33.

As shown in fig. 2, the oil cooling pipe set 40 of the oil-cooled four-stroke engine 1 includes a heat engine oil pipe 41 and a cooling oil pipe 42, wherein the heat engine oil pipe 41 and the cooling oil pipe 42 are respectively connected to the engine oil channel 14 of the engine body 10, in this embodiment, the heat engine oil pipe 41 is respectively connected to the heat engine oil inlet 311 of the oil cooler 30 and the heat engine oil outlet 151 of the cover plate 15 of the engine body 10, the cooling oil pipe 42 is respectively connected to the cooling oil inlet 312 of the oil cooler 30 and the cooling oil inlet 152 of the cover plate 15 of the engine body 10, the heat engine oil pipe 41 sends the engine oil in the engine oil channel 14 to the oil cooler 30 through the heat engine oil outlet 151 for cooling, and the cooled engine oil is sent back to the cooling oil inlet 152 through the cooling oil pipe 42 and then enters the engine body 10.

In the following further description of the process of cooling the engine body 10 by the oil cooler 30 and the oil in the oil-cooled four-stroke engine 1, referring to fig. 2 and 6A, taking the cold oil outlet 312 of the cooler body 31 of the oil cooler 30 as a starting point, as shown in fig. 2, a cold oil leaving from the oil cooler 30 flows from the cold oil outlet 312 of the cooler body 31 into the cold oil pipe 42, then flows into the cover plate 15 through the cold oil inlet 152 of the cover plate 15, and then flows into the first passage 143 inside the crankcase 111 through the oil inlet 142 of the crankcase 111 as shown in fig. 4B, and as the inner diameter of the sub-passage 144 is smaller than the inner diameter of the first passage 143, a major portion of the cold oil flows to the screw groove 16 of the cylinder 12 through the first passage 143, i.e. the portion of the first passage 143 corresponding to the cylinder 12, and the other minor portion flows into the sub-passage 144 and flows toward the crank chamber 113 of the crankcase 11.

Referring to fig. 6A and 6B, after passing through the front crankcase 111 through the first passage 143, the cold engine oil flows to the screw groove 16 of the cylinder 12, that is, the portion of the first passage 143 corresponding to the cylinder 12 and the cylinder head 13 absorbs the excessive heat generated by the combustion chamber 134 of the cylinder head 13, thereby cooling the engine body 10 and forming a hot engine oil, which sequentially passes through the inner passage 148 and enters the camshaft chamber 131; the hot engine oil enters the timing inner sprocket chamber 132 after passing through the camshaft chamber 131 of the cylinder head 13, and then flows to the rear crankcase 112 through the timing inner sprocket chamber 132 by gravity, as shown in fig. 5C, and the hot engine oil flows back to the sump 110 of the crankcase 11 through the return passage 145 after the timing inner sprocket chamber 132 merges with the engine oil flowing out of the crankshaft chamber 113 at a bottom in the rear crankcase 112.

As shown in fig. 6A, after the hot engine oil is collected in the oil tank 110 of the crankcase 11, the hot engine oil is pressurized by the oil pump 147 disposed between the oil tank 110 and the second passage 146 and passes through the second passage 146, then leaves the front crankcase 111 from the oil outlet 141 of the front crankcase 111, passes through the hot engine oil outlet 151 and the hot engine oil pipe 41 in sequence, enters the cooler body 31 from the hot engine oil inlet 311 of the oil cooler 30, finally is cooled by the cooler body 31, forms the cold engine oil and enters the cold engine oil pipe 42 for recirculation through the cold engine oil outlet 312; in this embodiment, since the oil cooler 30 is utilized to cool and lubricate the oil simultaneously, the maximum oil temperature of the hot oil can be reduced to less than 100 ℃, and the total weight of the oil-cooled four-stroke engine 1 shown in fig. 2 can be reduced by 17 kg, compared with the total weight of the water-cooled four-stroke engine 60 provided with the water tank 61, the cold water pipe 63, the hot water pipe 64 and the cooling water in fig. 7, which is 23 to 25 kg, the total weight of the oil-cooled four-stroke engine 1 can be reduced by about 6 to 8 kg; further, taking the specifications of 73mm cylinder diameter and 67.9mm crankshaft stroke as an example, the exhaust gas amount of the oil-cooled four-stroke engine 1 of the present invention is about 284.17 c.c. (73×73×3.1415×67.9/1000), so that the exhaust gas amount of 34.17cc is increased compared with the water-cooled four-stroke engine of 250c.c shown in fig. 7.

As can be seen from the above description, the oil-cooled four-stroke engine of the present invention is characterized in that the engine oil passage is formed inside the engine body, the oil cooler is disposed and fixed at one side of the flying umbrella fixing frame, an oil cooling pipe assembly is used to connect the engine oil passage and the oil cooler, the heat engine oil pipe of the oil cooling pipe assembly guides the heat engine oil inside the engine body from the oil outlet of the engine oil passage to the oil cooler, so as to cool the heat engine oil and form the cold engine oil, and then the cold engine oil pipe of the oil cooling pipe assembly is used to guide the cold engine oil back to the oil inlet of the engine oil passage, and the engine oil is repeatedly circulated, so that the engine oil can exert cooling and lubricating effects at the same time; in addition, the invention integrally forms a plurality of transverse reinforcing ribs and a plurality of longitudinal reinforcing arms on the front side and the rear side of the common shaft fixing column of the rear crankcase of the engine body so as to strengthen the common shaft fixing column and reduce the stress concentration of the rear crankcase caused by using the propeller; therefore, the oil-cooled four-stroke engine for the power flight parachute can utilize the engine oil cooler to cool the engine oil and indirectly cool the engine body without externally hanging a cooling water tank, so that the weight of the oil-cooled four-stroke engine is reduced, and the weight burden of users and the consumption of fuel oil for flight are reduced.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention, as will be apparent to those skilled in the art, without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An oil-cooled four-stroke engine for a powered parachute comprising:

an engine body, at least comprising a crankcase, a cylinder cover and an engine oil passage, wherein the engine oil passage penetrates through a side wall of the crankcase, the cylinder and the cylinder cover and is communicated with a camshaft chamber of the cylinder cover;

2. The oil-cooled four-stroke engine for a powered parachute of claim 1, wherein: the crankcase includes:

a sump extending downwardly from a bottom of the crankcase;

a front crankcase, a front side of which forms an engine oil inlet and an engine oil outlet;

a rear crankcase coupled to the front crankcase; and

the crank chamber is formed between the front crank case and the rear crank case and is communicated with the engine oil tank; and

the cylinder head includes a timing inner sprocket chamber located behind and in communication with the camshaft chamber, and the timing inner sprocket chamber extends through the rear side of the cylinder and the rear crankcase of the crankcase and in communication with the sump of the crankcase.

3. The oil-cooled four-cycle engine for a powered parachute of claim 2, wherein the oil passage comprises:

a first passage communicating with the oil inlet of the front crankcase, penetrating the front crankcase, the cylinder, and the side wall of the cylinder head, and communicating with the camshaft chamber of the cylinder head;

a sub-passage formed in the front crankcase to communicate the first passage with the crank chamber;

a return passage formed in the rear crankcase to communicate the timing inner sprocket chamber with the sump; and

and a second passage formed in the front crankcase to communicate with the sump.

4. An oil cooled four stroke engine for a powered parachute according to claim 3, wherein:

the outer side of the crankcase and the side wall of the cylinder and the cylinder cover correspond to each stud to form a screw groove;

the part of the first channel corresponding to the side wall of the cylinder and the cylinder cover is one of the screw grooves; and

the portion of the first passage of the oil passage corresponding to the cylinder head includes an inner passage, and the first passage communicates with the camshaft chamber through the inner passage.

5. The four stroke engine for a powered parachute of claim 3 or 4, further comprising an oil pump secured within the front crankcase and connected in series between the second passage and the sump.

6. The oil-cooled four-stroke engine for a powered parachute of claim 5, wherein:

this parachute mount contains:

a plurality of parachute-securing arms; and

a cross arm connected with two of the flying umbrella fixing arms; and

the oil cooler comprises:

a front fixing piece fixed on the cross arm of the flying umbrella fixing frame;

a rear fixing piece fixed on the cross arm of the flying umbrella fixing frame; and

the cooler body is clamped between the front fixing piece and the rear fixing piece.

7. The oil-cooled four-stroke engine for a powered parachute of claim 6, wherein:

a cover plate is fixed on the outer side of the front crankcase of the engine body, and the cover plate is positioned between the front crankcase of the engine body and the flying umbrella fixing frame, and comprises:

the cold engine oil inlet is connected with the cold engine oil pipe of the oil cooling pipe fitting group and is communicated with the engine oil inlet of the front crankcase; and

the heat engine oil outlet is connected with the heat engine oil pipe of the oil cooling pipe fitting group and is communicated with the engine oil outlet of the front crankcase; and

the oil-cooled tube set comprises:

a heat engine oil pipe connected to the heat engine oil inlet of the cooler body and the heat engine oil outlet of the cover plate; and

and the cold engine oil pipe is connected to the cold engine oil outlet of the cooler body and the cold engine oil inlet of the cover plate.

8. The oil cooled four stroke engine for a powered parachute of claim 3, wherein the inner diameter of the sub-passage of the oil passage is smaller than the inner diameter of the first passage of the oil passage.

9. The oil cooled four stroke engine for a powered parachute of claim 2, wherein the rear crankcase has a polycotton shaft extending upwardly from an outer side thereof, comprising:

a plurality of longitudinal reinforcing arms integrally formed on the front and rear sides of the polycosanol shaft fixing column; and

and a plurality of transverse reinforcing ribs respectively formed between adjacent longitudinal reinforcing arms at the rear side of the common shaft fixing column.

10. The oil cooled four stroke engine for a powered parachute of claim 9, wherein the propeller shaft mounting post of the rear crankcase is adapted for passage and mounting of a propeller shaft, and wherein the propeller shaft is connected to a propeller drive wheel.