阅读说明：本技术 一种发动机冷却水套结构 (Engine cooling water jacket structure ) 是由 郑杨 曾庆强 朱肃敬 何勇 于 2019-10-31 设计创作，主要内容包括：本发明涉及一种米勒循环发动机冷却水套结构,包括设在气缸体内的缸体水套、设在气缸盖内的缸盖水套、设在气缸体与气缸盖之间的气缸垫；缸体水套在靠近发动机前端的部位设有进水口,缸体水套在靠近发动机后端的部位设有出水孔,该出水孔与设置在气缸盖上的独立出水道相连,独立出水道的水道出口与缸体调温器连通；所述缸体水套与气缸间对应的部位设有三个“V”形水道,三个所述“V”形水道的一端连通缸体水套排气侧,对缸体热负荷最高的区域直接进行冷却。本发明能够提高暖机速度,提高运行时缸体的整体温度,降低冷却液总流量,减小水套流阻和水泵功耗,同时降低缸体缸间、缸盖鼻梁区排气汇集处最高温度,使各缸温度均匀。(The invention relates to a Miller cycle engine cooling water jacket structure, which comprises a cylinder body water jacket arranged in an air cylinder body, a cylinder cover water jacket arranged in an air cylinder cover, and an air cylinder gasket arranged between the air cylinder body and the air cylinder cover; the cylinder water jacket is provided with a water inlet at the position close to the front end of the engine, the cylinder water jacket is provided with a water outlet at the position close to the rear end of the engine, the water outlet is connected with an independent water outlet channel arranged on the cylinder cover, and a water channel outlet of the independent water outlet channel is communicated with the cylinder temperature regulator; and three V-shaped water channels are arranged at the corresponding positions between the cylinder body water jacket and the cylinder, and one ends of the three V-shaped water channels are communicated with the exhaust side of the cylinder body water jacket to directly cool the area with the highest thermal load of the cylinder body. The invention can improve the warming-up speed, improve the integral temperature of the cylinder body during operation, reduce the total flow of cooling liquid, reduce the flow resistance of the water jacket and the power consumption of the water pump, and simultaneously reduce the highest temperature of the exhaust convergence position between the cylinders of the cylinder body and the nose bridge area of the cylinder cover, so that the temperature of each cylinder is uniform.)

1. The utility model provides a Miller's cycle engine cooling water jacket structure, includes cylinder body water jacket (1) of establishing in the cylinder block, establishes the cylinder head water jacket in the cylinder head, establishes cylinder gasket (2) between cylinder block and cylinder head, characterized by:

a water inlet (11) is formed in the position, close to the front end of the engine, of the cylinder water jacket (1), and the water inlet is connected with an outlet of the water pump; a water outlet hole (12) is formed in the position, close to the rear end of the engine, of the cylinder body water jacket (1), the water outlet hole is connected with an independent water outlet channel (13) arranged on the cylinder cover, and a water channel outlet (14) of the independent water outlet channel (13) is communicated with the cylinder body temperature regulator; the corresponding position between the cylinder body water jacket (1) and the cylinder is provided with three V-shaped water channels (15), one end of each V-shaped water channel (15) is communicated with the top of the exhaust side position of the cylinder body water jacket, the other end of each V-shaped water channel is positioned between the exhaust side position and the intake side position of the cylinder body water jacket, and the other end of each V-shaped water channel is close to the top of the intake side position of the cylinder body water jacket, so that the area with the highest heat load of the cylinder body is directly cooled.

2. The miller cycle engine cooling water jacket structure according to claim 1, wherein: the cylinder cover water jacket is divided into a cylinder cover water jacket lower layer (3) and a cylinder cover water jacket upper layer (4).

3. The miller cycle engine cooling water jacket structure according to claim 2, wherein: the cylinder gasket (2) is provided with a cylinder cover water jacket upper water hole (21) at the position close to the front end of the engine, a cylinder body water jacket water outlet hole (22) at the position close to the rear end of the engine, a first/second cylinder upper water hole (23), a second/third cylinder upper water hole (24) and a third/fourth cylinder upper water hole (25) at the air inlet side close to the engine, and the three cylinder upper water holes are respectively in one-to-one correspondence with the other ends of the three V-shaped water channels (15) on the cylinder body water jacket (1); the three inter-cylinder water feeding holes are communicated with the cylinder cover water jacket upper layer (4);

the cylinder gasket (2) is provided with a cylinder nose bridge area water feeding hole (26), a two-cylinder nose bridge area water feeding hole (27), a three-cylinder nose bridge area water feeding hole (28) and a four-cylinder nose bridge area water feeding hole (29) on the exhaust side close to the engine.

4. The miller cycle engine cooling water jacket structure according to claim 3, wherein: five machining positions are reserved on the lower layer (3) of the water jacket of the cylinder cover from the front end of the engine to the rear end of the engine near the air inlet side of the engine, and a first machining hole (31), a second machining hole (32), a third machining hole (33), a fourth machining hole (34) and a fifth machining hole (35) are respectively arranged on the five machining positions; the five machining holes are communicated with the cylinder cover water jacket upper layer (4);

a lower front sand outlet hole (36), a lower cooling water channel (37) and a lower rear sand outlet hole (38) are sequentially formed in the lower layer (3) of the cylinder cover water jacket from front to back near the exhaust side of the engine; the lower cooling flume (37) is located at an IEM outlet collection; the lower cooling water channel (37) is mainly characterized in that cooling liquid is provided by a lower front sand outlet (36) and flows downwards to a lower rear sand outlet (38) to intensively cool an IEM gathering part, and the lower front sand outlet (36) and the lower rear sand outlet (38) are sealed by bowl plug interference fit.

5. The miller cycle engine cooling water jacket structure according to claim 3, wherein: a cylinder cover water jacket water inlet (41) is formed in the cylinder cover water jacket upper layer (4) close to the front end of the engine, and a cylinder cover water jacket water outlet (42) is formed in the cylinder cover water jacket upper layer close to the rear end of the engine; a water inlet (41) of the cylinder cover water jacket is communicated with a water inlet hole (21) of the cylinder cover water jacket on the cylinder gasket (2);

the spark plug is characterized in that four straight water channels (43) are arranged at the position, corresponding to the nose bridge area, of the cylinder cover water jacket upper layer (4), one end of each straight water channel (43) is communicated with the spark plug area, and the other end of each straight water channel is communicated with a water hole (26) in the nose bridge area of one cylinder, a water hole (27) in the nose bridge area of two cylinders, a water hole (28) in the nose bridge area of three cylinders and a water hole (29) in the nose bridge area of four cylinders on the cylinder gasket (2) in a one.

6. The positions of the cylinder cover water jacket upper layer (4) corresponding to the five machined holes on the cylinder cover water jacket lower layer (3) are respectively provided with a machined part (45); and the cylinder cover water jacket upper layer (4) is provided with an upper front sand outlet hole (46), an upper cooling water channel (47) and an upper rear sand outlet hole (48) from the front to the rear in sequence close to the exhaust side of the engine, and is in one-to-one correspondence with the lower front sand outlet hole (36), the lower cooling water channel (37) and the lower rear sand outlet hole (38) on the cylinder cover water jacket lower layer (3) respectively.

Technical Field

The invention relates to an automobile engine, in particular to an engine water jacket structure. In particular to a cooling water jacket structure of a Miller cycle engine.

Background

At present, a cooling system of an automobile engine mainly adopts a water cooling mode as a main mode, and the temperature of an engine body of the engine is reduced through circulation of cooling liquid. In order to meet the increasingly stringent requirements of oil consumption and emission regulations, a certain engine adopts a Miller cycle technology with high compression ratio, the high compression ratio increases the knocking tendency, and meanwhile, an IEM (integrated exhaust manifold) technology is adopted, and the IEM flow needs to be controlled.

In order to inhibit knocking, the highest temperature of a nose bridge area of a cylinder cover and the highest temperature between cylinders of a cylinder body need to be reduced, and the flow of cooling liquid is usually selected to be increased when the traditional water jacket is used for reducing the temperature, so that the flow resistance of the water jacket is increased, the power consumption of a water pump is increased, the heating time is prolonged, the friction loss is increased, and the emission and the oil consumption are not favorable; and because the water jacket entry is usually in one side of the engine, the coolant liquid flows from a jar to four jars (namely flow from front end to rear end), and perpendicular with bridge of the nose district water course, the bridge of the nose district temperature is difficult to reduce, the temperature homogeneity of each jar is difficult to control too, the maximum temperature difference of each jar can reach more than 30 ℃ at present.

In order to reduce exhaust interference, the integrated exhaust passage adopts a 421 structure (one exhaust pipe is used for each cylinder, then two exhaust pipes are combined into two, and finally the two pipes are combined into one), the temperature of the exhaust passage collection position is far higher than that of an integrated exhaust manifold of a 41 structure type (one exhaust pipe is used for each cylinder, and then the exhaust passage collection position is combined into one), so that the exhaust passage collection position needs to be effectively cooled, a water passage is separately arranged at the conventional water jacket position, four bowl plugs (namely bowl-shaped plugs are needed for sealing through interference fit), and the water leakage risk and the design cost are high.

CN 203640848U discloses a shunting engine cooling water jacket, which comprises a cylinder body water jacket and a cylinder cover water jacket corresponding to the cylinder body water jacket, wherein a sealing gasket is arranged between the cylinder body water jacket and the cylinder cover water jacket, the cylinder body water jacket is an annular water tank corresponding to the shape of a cylinder body, a water inlet is formed in the surface of one side of the cylinder body water jacket, and a water outlet is formed in the surface of the other side of the cylinder body water jacket; the two sides of the sealing gasket are provided with sealing gasket through holes corresponding to the notches of the cylinder water jacket; and cylinder cover water jacket through holes corresponding to the sealing gasket through holes are formed in the two sides of the cylinder cover water jacket. The water inlet is arranged on the exhaust side of the cylinder body, the water outlet is arranged on the air inlet side, the cooling liquid flows out from the air inlet side after passing through the cylinder body water jacket and the cylinder cover water jacket, the temperature of the exhaust side is reduced, the temperature of the air inlet side is improved, the temperature of the cylinder body tends to be consistent, the problems of thermal stress, thermal deformation and the like are solved, the utilization efficiency of the cooling liquid is high, the internal friction of the engine is less, the combustion efficiency of the engine is high, and the service life of engine parts is prolonged. This is, of course, a beneficial attempt in the art.

Disclosure of Invention

The invention aims to provide an engine water jacket structure which can improve the warming-up speed, improve the overall temperature of a cylinder body during operation, reduce the total flow of cooling liquid, reduce the flow resistance of a water jacket and the power consumption of a water pump, and simultaneously reduce the highest temperature of exhaust convergence positions between cylinders of the cylinder body and a bridge area of a bridge of a cylinder cover, so that the temperature of each cylinder is uniform, the sealing is improved, and the water leakage risk is reduced.

The invention relates to a Miller cycle engine cooling water jacket structure, which comprises a cylinder body water jacket arranged in an air cylinder body, a cylinder cover water jacket arranged in a cylinder cover and a cylinder gasket arranged between the air cylinder body and the cylinder cover, and is characterized in that:

the water jacket of the cylinder body is provided with a water inlet at the position close to the front end of the engine, and the water inlet is connected with the outlet of the water pump; the water jacket of the cylinder body is provided with a water outlet hole at the position close to the rear end of the engine, the water outlet hole is connected with an independent water outlet channel arranged on the cylinder cover, and a water channel outlet of the independent water outlet channel is communicated with the cylinder body temperature regulator; and the corresponding part between the cylinder body water jacket and the cylinder is provided with three V-shaped water channels, one ends of the three V-shaped water channels are communicated with the top of the exhaust side inter-cylinder position of the cylinder body water jacket, and the other ends of the three V-shaped water channels are positioned between the exhaust side inter-cylinder position and the air inlet side inter-cylinder position of the cylinder body water jacket and are close to the top of the air inlet side inter-cylinder position of the cylinder body water jacket, so that the region with the highest thermal load of the cylinder body is directly cooled.

Further, the cylinder cover water jacket is divided into a cylinder cover water jacket lower layer and a cylinder cover water jacket upper layer.

Further, the cylinder gasket is provided with a cylinder cover water jacket upper water hole at a position close to the front end of the engine, a cylinder body water jacket water outlet hole at a position close to the rear end of the engine, a first/second inter-cylinder upper water hole, a second/third inter-cylinder upper water hole and a third/fourth inter-cylinder upper water hole at an air inlet side close to the engine, and the three inter-cylinder upper water holes are respectively in one-to-one correspondence with the other ends of the three V-shaped water channels on the cylinder body water jacket; the three inter-cylinder water-feeding holes are communicated with the upper layer of the cylinder cover water jacket.

The cylinder gasket is provided with a cylinder nose bridge area water feeding hole, a two-cylinder nose bridge area water feeding hole, a three-cylinder nose bridge area water feeding hole and a four-cylinder nose bridge area water feeding hole on the side close to the exhaust side of the engine.

Furthermore, five machining parts are reserved on the lower layer of the water jacket of the cylinder cover from the front end of the engine to the rear end of the engine near the air inlet side of the engine, and a first machining hole, a second machining hole, a third machining hole, a fourth machining hole and a fifth machining hole are respectively arranged on the five machining parts; and the five machining holes are communicated with the upper layer of the cylinder cover water jacket.

A lower front sand outlet, a lower cooling water channel and a lower rear sand outlet are sequentially arranged on the lower layer of the cylinder cover water jacket from front to back near the exhaust side of the engine; the lower cooling water channel is positioned at the IEM outlet collection position; the lower cooling water channel mainly supplies cooling liquid through a lower front sand outlet, and flows to a lower rear sand outlet to intensively cool the IEM collection part, and the lower front sand outlet and the lower rear sand outlet are sealed by bowl plug interference fit.

Further, a cylinder cover water jacket water inlet is formed in the cylinder cover water jacket upper layer and is close to the front end of the engine, and a cylinder cover water jacket water outlet is formed in the cylinder cover water jacket upper layer and is close to the rear end of the engine; the water inlet of the cylinder cover water jacket is communicated with the water inlet hole of the cylinder cover water jacket on the cylinder gasket;

four straight water channels are arranged at the position, corresponding to the nose bridge area, of the upper layer of the cylinder cover water jacket, one ends of the four straight water channels are communicated with the spark plug area, and the other ends of the four straight water channels are communicated with a water feeding hole in a cylinder nose bridge area, a water feeding hole in a two-cylinder nose bridge area, a water feeding hole in a three-cylinder nose bridge area and a water feeding hole in a four-cylinder nose bridge area on the cylinder gasket in a one-to-one.

The parts of the upper layer of the cylinder cover water jacket corresponding to the five machined holes on the lower layer of the cylinder cover water jacket are respectively provided with a machined part; the upper layer of the cylinder cover water jacket is provided with an upper front sand outlet, an upper cooling water channel and an upper rear sand outlet from the front to the rear in sequence near the exhaust side of the engine, and the upper front sand outlet, the upper cooling water channel and the upper rear sand outlet are in one-to-one correspondence with a lower front sand outlet, a lower cooling water channel and a lower rear sand outlet on the lower layer of the cylinder cover water jacket respectively.

The invention has the following advantages:

(1) because the nose bridge area of the cylinder cover is provided with the straight water channel, and the V-shaped water channel is arranged between the cylinders of the cylinder body to accurately cool the area with the highest heat load of the engine body, the highest temperature of the engine body is greatly reduced; the sizes of the cylinder cushion holes at the corresponding positions of the straight water channel and the V-shaped water channel are adjusted, so that the effect of adjusting the flow of cooling liquid of the straight water channel and the V-shaped water channel is achieved, the temperature difference of each cylinder is controlled to be within 2 ℃, and the temperature uniformity of the combustion chamber is improved;

(2) the water jacket is matched with the cylinder gasket hole to accurately control a high-temperature area, so that the utilization efficiency of cooling liquid is high, the flow required by the whole water jacket is greatly reduced, the flow resistance is reduced along with the reduction of the flow resistance, and the power consumption for driving the water pump is reduced;

(3) because of the ingenious parting of the lower-layer water jacket, the lower cooling water channel at the IEM collection position is integrated in the lower-layer water jacket of the cylinder cover, four sealing bowl plugs are reduced into two sealing bowl plugs, the cost of the whole machine is reduced, and the casting process of the cylinder cover is simplified;

(4) the sectional area of the water outlet hole of the cylinder water jacket can be adjusted, so that the proportion of cooling liquid flowing into the cylinder water jacket and the cylinder cover water jacket can be changed, the temperature of the cylinder cover and the cylinder body is more uniform, and the cylinder body temperature regulator connected with the independent water outlet channel of the cylinder cover is matched to realize rapid temperature rise;

(5) different cooling effects can be realized only by changing five machining holes corresponding to the cylinder cover machining part and the cylinder cushion hole on the cylinder cushion, so that the effect of sharing the cylinder cover and the cylinder block blank by a platform project is realized, and the costs of management, design, molds and the like are greatly reduced.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the structure of a water jacket (sand core) of a cylinder block;

FIG. 3 is a schematic view of a cylinder head gasket;

fig. 4 is a structural schematic diagram of a lower layer (sand core) of a water jacket of a cylinder head.

FIG. 5 is a schematic structural view (bottom view) of a water jacket upper layer (sand core) of a cylinder head;

FIG. 6 is a schematic view of the structure of a water jacket (sand core) of a cylinder head;

in the figure:

1-cylinder water jacket, 11-water inlet, 12-water outlet, 13-independent water outlet channel, 14-water outlet channel, 15-V-shaped water channel;

2-cylinder gasket, 21-cylinder cover water jacket upper water hole, 22-cylinder body water jacket water hole, 23-one/two-cylinder upper water hole, 24-two/three-cylinder upper water hole, 25-three/four-cylinder upper water hole, 26-one-cylinder nose beam area upper water hole, 27-two-cylinder nose beam area upper water hole, 28-three-cylinder nose beam area upper water hole, 29-four-cylinder nose beam area upper water hole;

3-cylinder cover water jacket lower layer, 31-first machine hole machining, 32-second machine hole machining, 33-third machine hole machining, 34-fourth machine hole machining, 35-fifth machine hole machining, 36-lower front sand outlet, 37-lower cooling water channel, 38-lower rear sand outlet;

4-cylinder cover water jacket upper layer, 41-cylinder cover water jacket water inlet, 42-cylinder cover water jacket water outlet, 43-straight water channel, 45-processing position, 46-upper front sand outlet, 47-upper cooling water channel, and 48-upper rear sand outlet.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1 to 6, a miller cycle engine cooling water jacket structure includes a cylinder block water jacket 1 disposed in a cylinder block, a cylinder head water jacket disposed in a cylinder head, and a cylinder gasket 2 disposed between the cylinder block and the cylinder head, and is characterized in that:

the cylinder body water jacket 1 is provided with a water inlet 11 at the position close to the front end of the engine, and the water inlet is connected with the outlet of the water pump; a water outlet hole 12 is formed in the position, close to the rear end of the engine, of the cylinder water jacket 1, the water outlet hole is connected with an independent water outlet channel 13 arranged on the cylinder cover, and a water outlet 14 of the independent water outlet channel 13 is communicated with the cylinder thermostat; after entering the cylinder water jacket, the cooling liquid flows to the rear end of the engine from the front end of the engine along the air inlet side of the engine and the exhaust side of the engine respectively, the flow distribution of the cylinder water jacket and the cylinder water jacket can be realized by adjusting the sectional area of the water outlet hole, the quick temperature rise of the cylinder is realized by closing the cylinder temperature regulator, and the friction of the piston and the connecting rod is reduced.

Three V-shaped water channels 15 are arranged at the corresponding positions between the cylinder body water jacket 1 and the cylinders, one end of each V-shaped water channel 15 is communicated with the top of the position between the exhaust side cylinders of the cylinder body water jacket, the other end of each V-shaped water channel 15 is positioned between the position between the exhaust side cylinders of the cylinder body water jacket and the position between the intake side cylinders of the cylinder body water jacket and is close to the top of the position between the intake side cylinders of the cylinder body water jacket, and the exhaust side of the cylinder body water jacket directly cools the area with the highest heat load of the cylinder.

The cylinder cover water jacket is divided into a cylinder cover water jacket lower layer 3 and a cylinder cover water jacket upper layer 4.

The cylinder gasket 2 is provided with a cylinder cover water jacket upper water hole 21 at a position close to the front end of the engine, a cylinder cover water jacket water outlet hole 22 at a position close to the rear end of the engine, a first/second inter-cylinder upper water hole 23, a second/third inter-cylinder upper water hole 24 and a third/fourth inter-cylinder upper water hole 25 at an air inlet side close to the engine, the three inter-cylinder upper water holes (23, 24 and 25) are respectively in one-to-one correspondence with the other ends of the three V-shaped water channels 15 on the cylinder cover 1, and the three inter-cylinder upper water holes are communicated with the cylinder cover water jacket upper layer 4. The highest temperature uniformity of the throttle cylinder can be improved by directly cooling the area with the highest heat load of the cylinder and adjusting the cross sections of the water feeding holes among the three cylinders.

The cylinder gasket 2 is provided with a cylinder nose bridge region upper water hole 26, a two-cylinder nose bridge region upper water hole 27, a three-cylinder nose bridge region upper water hole 28 and a four-cylinder nose bridge region upper water hole 29 on the side close to the exhaust side of the engine.

The flow of the water feeding holes 26 in the first cylinder nose bridge area, the water feeding holes 27 in the second cylinder nose bridge area, the water feeding holes 28 in the third cylinder nose bridge area, the water feeding holes 29 in the fourth cylinder nose bridge area, the water feeding holes 23 in the first cylinder and the second cylinder, the water feeding holes 24 in the second cylinder and the third cylinder and the water feeding holes 25 in the fourth cylinder to the cylinder cover water jacket is strictly controlled through CFD calculation, the total flow of the water feeding holes is guaranteed to be only below 10% of the flow of the cylinder cover water jacket, and the cylinder body is guaranteed to have higher heating speed when the cylinder body temperature regulator is closed.

The cylinder cover water jacket is divided into a cylinder cover water jacket lower layer 3 and a cylinder cover water jacket upper layer 4; the lower layer of the cylinder head water jacket is wrapped in the lower area of the IEM, and the upper layer of the cylinder head water jacket is wrapped in the combustion chamber area, the spark plug area and the upper area of the IEM;

five machining positions are reserved on the cylinder head water jacket lower layer 3 from the front end of the engine to the rear end of the engine on the side close to the air inlet of the engine, and a first machining hole 31, a second machining hole 32, a third machining hole 33, a fourth machining hole 34 and a fifth machining hole 35 are formed in the five machining positions respectively; the five machining holes (31, 32, 33, 34 and 35) are communicated with the cylinder cover water jacket upper layer 4 and correspond to the front end and the rear end of the cylinder cover water jacket upper layer 4 and three cylinders on a cylinder cover respectively, and the sizes of the five machining holes are determined through CFD analysis, so that the fine control of the lower IEM flow is realized;

the cylinder cover water jacket lower layer 3 is provided with a lower front sand outlet hole 36, a lower cooling water channel 37 and a lower rear sand outlet hole 38 in sequence from front to back near the exhaust side of the engine; the lower cooling flume 37 is located at the IEM outlet collection; the lower cooling water channel 37 mainly supplies cooling liquid from the lower front sand outlet 36 and flows downward to the lower rear sand outlet 38 to intensively cool the collection part of the IEM, and the lower front sand outlet 36 and the lower rear sand outlet 38 are sealed by using a bowl plug interference fit.

A cylinder cover water jacket water inlet 41 is formed in the cylinder cover water jacket upper layer 4 close to the front end of the engine, and a cylinder cover water jacket water outlet 42 is formed in the cylinder cover water jacket upper layer close to the rear end of the engine; the water inlet 41 of the cylinder cover water jacket is communicated with the water hole 21 of the cylinder cover water jacket on the cylinder gasket 2, and cooling liquid is mainly provided through the water hole 21 of the cylinder cover water jacket and is used for cooling a spark plug area and an IEM upper area;

four straight water channels 43 are arranged at the position, corresponding to the nose bridge area, of the cylinder cover water jacket upper layer 4, one end of each of the four straight water channels 43 is communicated with the spark plug area, and the other end of each of the four straight water channels 43 is communicated with a water inlet hole 26 in the cylinder nose bridge area, a water inlet hole 27 in the two-cylinder nose bridge area, a water inlet hole 28 in the three-cylinder nose bridge area and a water inlet hole 29 in the four-cylinder nose bridge area on the cylinder gasket 2 in a one-to-one correspondence manner; a small amount of cooling liquid is provided by the cylinder body water jacket 1 and is used for directly cooling the nose bridge area; the uniformity of the highest temperature of the cylinder head is improved by adjusting the sectional areas of the four holes (26, 27, 28, 29), and the temperature difference is controlled within 2 ℃.

The parts of the cylinder cover water jacket upper layer 4 corresponding to the five machined holes on the cylinder cover water jacket lower layer 3 are respectively provided with a machining part 45; the cylinder cover water jacket upper layer 4 is provided with an upper front sand outlet 46, an upper cooling water channel 47 and an upper rear sand outlet 48 in sequence from front to back near the exhaust side of the engine, and the upper front sand outlet, the upper cooling water channel and the upper rear sand outlet correspond to the lower front sand outlet 36, the lower cooling water channel 37 and the lower rear sand outlet 38 on the cylinder cover water jacket lower layer 3 one by one respectively.

One end of three V-shaped water channels 15 on the cylinder water jacket 1 is communicated with the exhaust side of the cylinder water jacket to directly cool the area with the highest heat load of the cylinder; the other ends of the three V-shaped water channels 15 on the cylinder body water jacket 1 are connected with a first/second cylinder upper water hole 23, a second/third cylinder upper water hole 24 and a third/fourth cylinder upper water hole 25 on the air inlet side of the cylinder head gasket, and the three cylinder upper water holes are communicated with the cylinder head water jacket upper layer 4. The highest temperature uniformity of the throttle cylinder body can be improved by adjusting the sections of the three holes.