Engine cooling circulation system

Abstract

An engine cooling circulation system includes an engine cylinder block and a cylinder head disposed at the top of the engine cylinder block, a thermostat is disposed at the front end of the cylinder head, and a water pump for providing power for the coolant in the engine cooling circulation system. A main cooling circuit and a secondary cooling circuit are formed in parallel from the water outlet cavity of the water pump. The main cooling circuit passes through the cylinder block coolant circuit and the cylinder head coolant circuit of the engine, and then returns to the water pump water inlet cavity through the thermostat valve seat water inlet cavity or returns to the water pump water inlet cavity after cooling through the water tank after the thermostat; the secondary cooling circuit is divided into two parallel branches after passing through the corresponding bypass pipe, one of which is the EGR valve cooling branch, and the other is the EGR cooler cooling branch. The parallel connection mode has a simple structure, a short pipeline, and a small resistance along the way; the head requirement of the water pump is low, and the volume of the water pump can be reduced, so that the structure is compact and the energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to an engine coolant circulation system. Background Art

[0002] With the improvement of environmental protection requirements for motor vehicle emission standards and the improvement of driving comfort requirements of agricultural machinery users, the application of agricultural tractor exhaust gas after-treatment devices and cab temperature control is becoming more and more widespread. In addition to realizing the traditional cooling function, the engine coolant circulation system also needs to meet the different new requirements for cooling and heating of exhaust gas after-treatment devices, usually SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) devices, and cab air conditioning and heating systems. These new requirements increase the complexity of the coolant circulation system on the one hand, and on the other hand, due to the addition of exhaust gas after-treatment devices in the limited engine compartment space, the surplus space of the engine is reduced, which increases the difficulty of cooling pipeline layout.

[0003] The coolant circulation system in the prior art has the following problems:

[0004] First, the layout of the pipeline and the selection of the location of the liquid collection point of the heating circulation system result in the width of the agricultural diesel engine becoming larger, which is inconsistent with the trend of miniaturization design requirements of agricultural diesel engines.

[0005] At present, the main layout of the common coolant circulation system is that the coolant enters the engine body through the water pump, flows through various cooling parts in sequence, and finally flows out through the thermostat, returns after the water tank is cooled by the fan. The entire circulation loop is connected in series, the coolant flow is long, and the flow resistance is superimposed, so the head requirement of the water pump is relatively high. In addition, in the prior art, the coolant outlet position of the heating circulation loop is usually selected near the thermostat at the front end of the engine cylinder head, while the cab heating system and the urea tank in the SCR that need to be heated on the tractor are both located at the rear end of the engine compartment. Therefore, the coolant flowing from the rear end to the front end inside the engine needs to be led back from the front end to the rear end by an external pipeline to be used by the cab heating system and the urea tank in the SCR. Such a structure not only causes the entire coolant circulation loop to be turned, but also increases the number of components that need to be avoided along the way (such as the exhaust manifold, EGR, supercharger, tractor hood bracket, air filter bracket, etc. arranged on the cylinder head that need to be avoided), resulting in a longer external pipeline with a complex shape and difficult fixing, which increases the loss of coolant along the way and increases the flow requirement for the water pump. The high lift and high flow requirements of the water pump lead to an increase in the overall dimensions of the water pump. The water pump is usually located at the maximum lateral position at the front end of the agricultural diesel engine. The overall dimensions of the water pump directly determine the overall width boundary of the agricultural diesel engine. Therefore, the increase in the overall dimensions of the water pump directly leads to an increase in the overall width boundary of the agricultural diesel engine, which is inconsistent with the trend of miniaturization design requirements of agricultural diesel engines.

[0006] Second, in the prior art, the layout structure of the coolant circulation system pipeline is complex and difficult to assemble.

[0007] In the prior art, it is common that the water inlet of the engine body and the water outlet of the cylinder head are arranged at the front end of the engine cylinder body. Since a fan, water pump, generator, air-conditioning compressor, drive pulley and various idler pulleys are usually arranged there, the available space there is small, making it difficult to assemble the entire engine.

[0008] In order to solve the above problems, Anhui Jianghuai Automobile Co., Ltd. applied for a patent named "A diesel engine cooling system" with the authorization announcement number CN 103352767 In the technical solution disclosed in B's invention patent, the water inlet pipe of the engine is moved from the front end of the engine to the intake side or exhaust side of the engine cylinder block, which facilitates the overall installation of the engine, but has the following shortcomings: in this technical solution, since the impeller axis of the water pump is perpendicular to the front end face of the engine cylinder block, and the water pump outlet axis is parallel to the front end face of the engine cylinder block, the water pump inlet axis and the water pump outlet axis are perpendicular to each other. The result of such a structure is that under the limitation of a small lateral distance (the distance between the impeller axis of the water pump and the engine cylinder block), it is difficult for the casting of its water pump housing to simultaneously achieve the turning and smooth transition of the flow channel from the water pump inlet to the water pump outlet, resulting in excessive local water flow velocity or blockage, causing cavitation and other faults; if the lateral distance is increased, although the above problems can be solved, it will cause the installation position of the impeller axis of the water pump to be far away from the central axis of the crankshaft, thereby increasing the lateral size of the entire engine system, which may interfere with the vehicle tires when the vehicle turns.

[0009] In summary, due to the above-mentioned problems in the existing agricultural diesel engine coolant circulation system, it is necessary to develop an agricultural diesel engine coolant circulation system with appropriate pipeline inlet and outlet positions, reasonable pipeline direction, low flow resistance, compact structure, and safe and reliable use. Summary of the invention

[0010] In order to solve the above technical problems, the present invention provides an engine cooling circulation system.

[0011] The technical solution adopted by the present invention to solve the above technical problems is: an engine cooling circulation system, including an engine cylinder block and a cylinder head arranged at the top of the engine cylinder block, a thermostat is arranged at the front end of the cylinder head, and also includes a water pump for providing power for the coolant in the engine cooling circulation system, a main cooling circuit and a secondary cooling circuit are formed in parallel starting from the water outlet chamber of the water pump, the main cooling circuit passes through the cylinder block coolant circuit and the cylinder head coolant circuit of the engine, and then returns to the water pump water inlet chamber through the thermostat valve seat water inlet chamber or returns to the water pump water inlet chamber after cooling through the water tank after the thermostat; the secondary cooling circuit is divided into two parallel branches after passing through the corresponding bypass pipe, one of which is the EGR valve cooling branch, and the EGR valve cooling branch is merged into the thermostat valve seat water inlet chamber after passing through the EGR valve; the other branch is the EGR cooler cooling branch, The EGR cooler cooling branch directly enters the cab heating system after passing through the EGR cooler, and then returns to the water inlet chamber of the water pump; or the EGR cooler cooling branch passes through the EGR cooler, first passes through the pipe joint located at the rear end of the cylinder head, then enters the cab heating system and then returns to the water inlet chamber of the water pump, and the pipe joint includes at least three interconnected ends, one of which is connected to the cylinder head coolant circuit, and the other two ends are respectively connected to the return pipe of the EGR cooler and the water inlet pipe of the cab heating system.

[0012] Furthermore, it also includes an oil cooling circuit connected in parallel with the main cooling circuit, and the oil cooling circuit starts from the water outlet chamber of the water pump and returns to the water inlet chamber of the water pump after passing through the machine cooler.

[0013] Furthermore, an air cooler housing is installed on the front side of the engine cylinder block, and a water pump body of the water pump is installed on the front end surface of the air cooler housing. The water pump outlet cavity is formed by a groove precast on the air cooler housing and a guide block precast on the water pump body.

[0014] Furthermore, the machine cooler is installed on the rear end surface of the machine cooler housing, and the oil cooling shunt channel connecting the machine cooler and the water outlet cavity of the water pump is arranged inside the machine cooler housing.

[0015] Furthermore, it also includes an SCR nozzle cooling circuit that cools the SCR nozzle from the SCR nozzle cooling interface. The SCR nozzle cooling interface is arranged on the engine cylinder body and is connected to the cylinder body coolant circuit. The SCR nozzle cooling circuit returns to the water pump water inlet chamber after passing through the SCR nozzle.

[0016] Furthermore, it also includes a urea tank heating circuit for heating the urea tank. The urea tank heating circuit starts from a urea tank heating interface connected to a cylinder coolant circuit, passes through the urea tank, and returns to the water inlet chamber of the water pump.

[0017] Furthermore, in the main cooling circuit, the circulation loop that returns to the water pump water inlet chamber through the cylinder block coolant circuit, the cylinder head coolant circuit and the thermostat valve seat water inlet chamber is a small circulation loop, and the small circulation loop also includes a small circulation return water chamber precast in the engine cylinder head for directing the coolant from the thermostat valve seat water inlet chamber to the water pump water inlet chamber, and a small circulation return water channel arranged in the engine cylinder block, and the small circulation return water channel is composed of vertically intersecting vertical machine holes and horizontal machine holes, the vertical machine holes are connected to the small circulation return water chamber, and the horizontal machine holes are connected to the water pump water inlet chamber.

[0018] Furthermore, it also includes an oil cooling circuit, which diverts the oil from the water pump outlet chamber through the oil cooling shunt channel, and returns to the water pump water inlet chamber through the oil cooling reflux channel after passing through the machine cooler. The oil cooling shunt channel and the oil cooling reflux channel are both arranged in the machine cooler housing.

[0019] Beneficial effects:

[0020] According to the present invention, a connection method in which the main cooling circuit and the auxiliary cooling circuit are arranged in parallel is adopted, and the water intake point of the cab heating system is arranged at the rear end of the engine. The structure is simple, the pipeline is short, and the resistance along the way is small; the head requirement of the water pump is low, the volume of the water pump can be reduced, the structure is compact, and the energy consumption is reduced.

[0021] Furthermore, the oil cooling circuit is also connected in parallel with the main cooling circuit; the SCR nozzle cooling circuit and the urea tank heating circuit are connected in parallel to take water from the engine cylinder coolant circuit, and the pipeline layout is scientific. According to the analysis and product experimental verification based on the performance simulation calculation method, the present invention has obvious beneficial and practical effects such as reasonable cooling flow distribution, moderate coolant supply to each circuit, small resistance along the way, and low power consumption.

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic block diagram of a preferred embodiment of the present invention.

[0024] Figure 2 It is a schematic diagram of the overall external structure of the present invention.

[0025] Figure 3 for Figure 2 Horizontal cross-sectional view of the reclaimed water pump body 1.

[0026] Figure 4 for Figure 2 Cross-sectional view of the engine corner (thermostat valve seat water inlet cavity 14)

[0027] Figure 5It is a schematic diagram of the structure of the cylinder block coolant circuit and cylinder head coolant circuit in the engine.

[0028] Figure 6 for Figure 5 Schematic diagram of the main structure.

[0029] Figure 7 It is a schematic cross-sectional structure diagram of the lower water jacket 10 in the cylinder head.

[0030] Figure 8 for Figure 5 A partial exploded view of the . DETAILED DESCRIPTION

[0031] like Figure 1-Figure 3 As shown, an engine cooling circulation system includes an engine block and a cylinder head arranged on the top of the engine block, a thermostat is arranged at the front end of the cylinder head, and also includes a water pump for providing power for the coolant in the engine cooling circulation system.

[0032] A main cooling circuit and a sub-cooling circuit are formed in parallel starting from the water pump outlet chamber 102. The main cooling circuit returns to the water pump inlet chamber 101 through the engine's cylinder block coolant circuit, cylinder head coolant circuit and thermostat valve seat inlet chamber 14, or returns to the water pump inlet chamber 101 after the thermostat through the water tank for cooling.

[0033] The auxiliary cooling circuit is divided into two parallel branches after passing through the corresponding bypass pipe, one of which is the EGR valve cooling branch. After passing through the EGR valve, the EGR valve cooling branch is merged into the thermostat valve seat water inlet chamber 14. The other branch is the EGR cooler cooling branch. After passing through the EGR cooler, the EGR cooler cooling branch directly enters the cab heating system and then returns to the water pump water inlet chamber 101 (that is, the hot water used by the cab heating system comes from the EGR cooler); or after passing through the EGR cooler, the EGR cooler cooling branch first passes through the pipe joint 13 provided at the rear end of the cylinder head and then enters the cab heating system and then returns to the water pump water inlet chamber 101. The pipe joint 13 includes at least three interconnected ends, one of which is connected to the cylinder head coolant circuit, and the other two ends are respectively connected to the return pipe of the EGR cooler and the water inlet pipe of the cab heating system.

[0034] The engine cooling circulation system also includes an oil cooling circuit connected in parallel with the main cooling circuit. The oil cooling circuit is divided from the water pump outlet chamber 102 and flows back to the water pump inlet chamber 101 after passing through the engine cooler 2.

[0035] The engine cooling circulation system also includes an SCR nozzle cooling circuit that cools the SCR nozzle starting from the SCR nozzle cooling interface 9. The SCR nozzle cooling interface 9 is arranged on the engine cylinder body and is connected to the coolant circuit in the cylinder body. The SCR nozzle cooling circuit returns to the water pump water inlet chamber 101 after passing through the SCR nozzle.

[0036] The engine cooling circulation system also includes a urea tank heating circuit for heating the urea tank. The urea tank heating circuit starts from the urea tank heating interface connected to the cylinder coolant circulation circuit, passes through the urea tank, and then returns to the water pump water inlet chamber 101. The urea tank heating interface can be an interface that is independent of the SCR nozzle cooling interface 9 and is provided on the engine cylinder. Preferably, the urea tank heating interface and the SCR nozzle cooling interface 9 share the same interface. In this embodiment, the SCR nozzle cooling interface 9 is shared, and after being led out from the SCR nozzle 9, it is divided into two paths using an external pipe, one for the SCR nozzle cooling circuit and the other for the urea tank heating circuit.

[0037] like Figure 2 and Figure 3 As shown, in this preferred embodiment, an air cooler housing 21 is installed on the front side of the engine cylinder block, and the water pump body 1 of the water pump is installed on the front end surface of the air cooler housing 21. The water pump outlet cavity 102 is formed by a groove precast on the air cooler housing 21 and a guide block 3 precast on the water pump body 1. The coolant flows in a direction roughly as shown in FIG. Figure 2 As shown by the arc arrow in the middle. In this structure, the center line of the water pump water inlet chamber 101 is set to be parallel to the side of the engine cylinder body according to the flow direction of the coolant. The use of this structure allows the water pump outlet chamber 102 to meet the use requirements while having a compact installation structure, so that the water pump can achieve smooth turning of the flow channel from the water pump inlet to the water pump outlet (i.e., between the water pump water inlet chamber 101 and the water pump outlet chamber 102) at a relatively small lateral distance (A=40-45mm) (the distance between the impeller axis of the water pump and the engine cylinder body), which has a good guiding effect on the coolant.

[0038] The cylinder coolant circuit includes a main water channel 4 connected to the water pump outlet chamber 102, water inlet channels 5 for each cylinder connected to the main water channel 4, annular channels 6 corresponding to the water inlet channels 5 of each cylinder, and a water outlet 7 on the top surface of the cylinder connected to the annular channels 6.

[0039] The annular channel 6 can be set at a position corresponding to the high heat load area of ​​the engine cylinder (referring to the area between the top surface of the first piston ring and the bottom surface of the last piston ring when the piston runs to the top dead center), preferably at a higher position in the high heat load area. The annular channel 6 set at this position can adopt a smaller height H, which can not only better meet the coolant flow rate and heat exchange requirements in the high heat load area, but also the smaller height H can reduce the volume of the annular channel 6 under the condition of the same width, so that a water pump with a smaller flow rate can be used in conjunction.

[0040] The cylinder head coolant circuit includes a lower water jacket 10 independent of each cylinder, an integral upper water jacket 11, upper and lower water jacket communication holes 12, and a thermostat valve seat water inlet cavity 14 connected to the integral upper water jacket 11. In this embodiment, the lower water jacket 10 has a height B=12mm, a coolant channel width C1 between two intake ducts of 5mm; a coolant channel width C2 between two exhaust ducts of 4mm; and a coolant channel width C3 between intake and exhaust ducts of 5mm. In practical applications, the parameters of the lower water jacket can be selected according to actual needs using existing technology. The lower water jacket 10 independent of each cylinder is connected to the corresponding cylinder top surface water outlet 7.

[0041] In the main cooling circuit, the circulation loop that returns to the water pump water inlet chamber 101 after passing through the cylinder block coolant circuit, the cylinder head coolant circuit and the thermostat valve seat water inlet chamber 14 is a small circulation loop. The small circulation loop also includes a small circulation return water chamber 15 precast in the engine cylinder head for directing the coolant from the thermostat valve seat water inlet chamber 14 to the water pump water inlet chamber 101 and a small circulation return water channel 8 provided in the engine cylinder block. The small circulation return water channel 8 is composed of vertical machine holes and horizontal machine holes that intersect vertically. The vertical machine holes are connected to the small circulation return water chamber 15, and the horizontal machine holes are connected to the water pump water inlet chamber 101.

[0042] The thermostat valve seat water inlet chamber 14 and the small circulation water inlet chamber 15 are integrally cast with the cylinder head, replacing the structure in the prior art that uses the thermostat housing as the thermostat valve seat water inlet chamber 14 and the small circulation water inlet chamber 15, saving the number of parts and reducing the overall width of the front end face of the engine.

[0043] The small circulation water return channel 8 adopts two vertically intersecting machined holes to replace the small circulation water return pipe in the prior art, which saves the number of parts and has a more compact structure.

[0044] In the preferred embodiment, the EGR valve cooling circuit in the auxiliary cooling circuit is diverted from the bypass channel (external pipe) 19 through the EGR valve and then enters the thermostat valve seat water inlet chamber 14 arranged at the front end of the cylinder head from the bypass interface 16.

[0045] In this preferred embodiment, another branch in the auxiliary cooling circuit passes through the EGR cooler and is connected to the D end of the pipe joint 13 (i.e., the return pipe of the EGR cooler is connected to the D end), and the water inlet pipe of the cab heating system (i.e., the water intake pipe of the cab heating system) is connected to the E end of the pipe joint 13. The pipe joint 13 also includes at least a third end, and the third end is connected to the cylinder head coolant circuit. In other words, in this preferred embodiment, the hot water going to the cab heating system comes from both the return pipe of the EGR cooler and the coolant in the engine cylinder head. Figure 5 The pipe joint 13 shown in the figure has four ends, and the fourth end is connected to the air compressor. That is to say, in the present invention, the liquid inlet (connected to the third end of the pipe joint 13) for returning to the cylinder head from the air compressor and other parts is arranged at the rear end of the engine cylinder head, thereby avoiding crowding of the cold parts at the front end of the engine.

[0046] The simulation analysis results confirm that the flow rate and temperature of the EGR cooler's cooled return water can meet the requirements of the cab heating system. Therefore, the EGR cooler's cooled return water can be directly used to heat the cab heating system. In this preferred embodiment, the warm air intake pipe passes through the pipe joint 13 installed at the rear end of the cylinder head, and the coolant in the cylinder head can be used as an alternative. This structure of the present invention has a short external pipeline, a simple shape, and is easy to fix.

[0047] In the SCR nozzle cooling circuit, the SCR nozzle cooling interface 9 is connected to the annular channel 6 in the cylinder coolant circuit. The SCR nozzle cooling circuit uses an external pipeline to connect the SCR nozzle and the water pump water inlet chamber 101. Bypass ports are set on the water inlet pipe and the water outlet pipe of the SCR nozzle cooling circuit, and the two ends of the urea tank heating circuit are respectively connected to the bypass ports on the water inlet and outlet pipes of the SCR nozzle cooling circuit, so as to be set in parallel with the SCR nozzle cooling circuit.

[0048] The simulation analysis results confirm that the coolant drawn from the annular channel 6 in the engine cylinder body and having a lower temperature than the front end of the cylinder head can fully meet the heating requirements of the urea tank. The SCR nozzle cooling interface 9 is arranged corresponding to the annular channel 6, which can shorten the length of the external pipeline and make the overall structure of the engine more compact.

[0049] The machine cooler 2 is installed on the rear end surface of the machine cooler housing 21 , and the oil cooling shunt channel 17 connecting the machine cooler 2 and the water pump outlet cavity 102 is arranged inside the machine cooler housing 21 .

[0050] In this preferred embodiment, the oil cooling circuit is preferably arranged in parallel with the main cooling circuit. The parallel structure requires a low water pump outlet head, so that a smaller water pump can be used, effectively reducing the overall size of the engine and reducing energy consumption.

[0051] As another embodiment, the oil cooling circuit may be connected in series before the main cooling circuit.

[0052] The oil cooling circuit flows from the water pump outlet chamber 102 through the oil cooling shunt channel 17, passes through the machine cooler 2, and then flows back to the water pump inlet chamber 101 through the oil cooling reflux channel 18. The oil cooling shunt channel 17 and the oil cooling reflux channel 18 are both arranged in the machine cooler housing 21, and the oil cooling shunt channel 17 is located above the water pump outlet chamber 102.

[0053] The cooling liquid circulation process of the above preferred embodiment is as follows:

[0054] When the engine is working, the coolant enters the water pump from the water pump inlet chamber 101, enters the water pump outlet chamber 102 after being pressurized, and a part of it enters the heat sink of the engine cooler 2 through the oil cooling shunt channel 17 on the upper part of the water pump outlet chamber 102, and then returns to the engine body small circulation return channel 8 through the oil cooling return channel 18, and returns to the water pump inlet chamber 101 from the small circulation return channel 8, thereby completing the circulation of the oil cooling circuit;

[0055] A part of the oil is diverted by the bypass channel 19 near the oil cooling diverter channel 17, flows to the EGR valve and the EGR cooler respectively, and enters the circulation of the EGR valve cooling branch and the EGR cooler branch;

[0056] The rest of the coolant flows along the guide direction of the guide block 3, enters the cylinder coolant circuit, and flows through the main water channel 4 through the water inlet channels 5 of each cylinder and enters the annular channel 6 around the cylinder liner. A part of the coolant entering the annular channel 6 directly enters the cylinder head coolant circuit through the top surface water outlet 7, and the remaining coolant flows along the periphery of the cylinder liner, cools the part, and then enters the cylinder head coolant circuit through the top surface water outlet 7. The coolant entering the cylinder head coolant circuit flows through the lower water jacket 10 and the upper and lower water jacket connecting holes 12 in sequence. , the water jacket 11 and the thermostat valve seat water inlet chamber 14 as a whole. If the temperature of the coolant in the thermostat valve seat water inlet chamber 14 is relatively high, the thermostat valve opens, and the coolant enters the water tank through the water tank connecting pipe 20 for cooling and then returns to the water pump water inlet chamber 101; if the temperature of the coolant in the thermostat valve seat water inlet chamber 14 is relatively low, the coolant directly enters the small circulation water inlet chamber 15, passes through the small circulation water outlet channel 8 on the cylinder body, and flows back to the water pump water inlet chamber 101, completing the circulation of the main cooling circuit.

[0057] The above is the circulation process of the coolant inside the engine.

[0058] In the coolant circuit to the engine external accessories:

[0059] The coolant in the annular channel 6 around the cylinder liner in the cylinder body is divided through the SCR nozzle cooling interface 9, one path cools the SCR nozzle and the other heats the urea tank. After that, the two paths merge and return to the water pump water inlet chamber 101, thereby realizing the circulation of the SCR nozzle cooling circuit and the urea tank heating circuit.

[0060] The coolant diverted from the water pump outlet chamber 102 through the bypass channel 19 cools the EGR valve, flows into the thermostat valve seat water inlet chamber 14 through the bypass interface 16, cools the EGR cooler, flows into the D end of the pipe joint 13 at the rear end of the cylinder head, and then flows out from the E end, flows to the cab heating system, and then returns to the water pump inlet chamber 101, finally completing the circulation of the EGR valve cooling branch and the EGR cooler cooling branch, and realizing the water supply to the cab heating system at the same time.

[0061] The "rear end" mentioned in this article refers to the end corresponding to the end of the engine connected to the gearbox, and the front end is the other end opposite to the rear end. The "water" or "coolant" mentioned in this article can be uniformly understood as coolant, that is, cooling medium.

[0062] The present invention uses a performance simulation calculation method for scientific design. The product has been verified by experiments to have obvious beneficial and practical effects such as reasonable cooling flow distribution, moderate coolant supply, small resistance along the way, and low power consumption in the pipeline direction.

[0063] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. An engine cooling circulation system, comprising an engine cylinder block and a cylinder head disposed on the top of the engine cylinder block, a thermostat disposed at the front end of the cylinder head, and a water pump for providing power for the coolant in the engine cooling circulation system, Features: Starting from the water pump outlet chamber, there is a main cooling circuit and a sub-cooling circuit formed in parallel. The main cooling circuit passes through the engine's cylinder block coolant circuit and cylinder head coolant circuit, then returns to the water pump water inlet chamber through the thermostat valve seat water inlet chamber, or returns to the water pump water inlet chamber after passing through the thermostat through the water tank for cooling; the sub-cooling circuit is divided into two parallel branches after passing through the corresponding bypass pipe, one of which is the EGR valve cooling branch, which passes through the EGR valve and merges into the thermostat valve seat water inlet chamber; the other branch is the EGR cooler cooling branch, which passes through the EGR cooler and directly returns to the water pump water inlet chamber. Entering the cab heating system and then returning to the water pump water inlet chamber, or the EGR cooler cooling branch passes through the EGR cooler, first passes through a pipe joint arranged at the rear end of the cylinder head, then enters the cab heating system and then returns to the water pump water inlet chamber, the pipe joint comprising at least three interconnected ends, one of which is connected to the cylinder head coolant circuit, and the other two ends are respectively connected to the return pipe of the EGR cooler and the water inlet pipe of the cab heating system; and also comprising an oil cooling circuit connected in parallel with the main cooling circuit, the oil cooling circuit starting from the water pump outlet chamber (102) through the engine cooler (2) and then returning to the water pump water inlet chamber (101); An engine cooler housing (21) is mounted on the front side of the engine cylinder block, the water pump body of the water pump is mounted on the front face of the engine cooler housing, and the water pump outlet cavity (102) is formed by a combination of a groove precast on the engine cooler housing (21) and a guide block (3) precast on the water pump body; in the main cooling circuit, the circulation loop that returns to the water pump water inlet cavity through the cylinder coolant circuit, the cylinder head coolant circuit and the thermostat valve seat water inlet cavity is a small circulation loop, and the small circulation loop also includes a small circulation return water precast in the engine cylinder head for guiding the coolant from the thermostat valve seat water inlet cavity to the water pump water inlet cavity (101). The invention relates to an oil cooling circuit, wherein the oil cooling circuit is divided from the water pump outlet chamber through the oil cooling shunt channel (17), and then flows back to the water pump inlet chamber (101) through the oil cooling reflux channel (18) after passing through the engine cooler. The oil cooling shunt channel (17) and the oil cooling reflux channel (18) are both arranged in the engine cylinder body.

2. An engine cooling circulation system according to claim 1, Features: The machine cooler (2) is mounted on the rear end surface of the machine cooler housing (21), and an oil cooling shunt channel (17) connecting the machine cooler (2) and the water pump outlet cavity (102) is arranged inside the machine cooler housing (21).

3. An engine cooling circulation system according to claim 1, Features: It also includes an SCR nozzle cooling circuit that cools the SCR nozzle starting from the SCR nozzle cooling interface (9), wherein the SCR nozzle cooling interface (9) is arranged on the engine cylinder body and is connected to the cylinder body coolant circuit, and the SCR nozzle cooling circuit returns to the water pump water inlet chamber (101) after passing through the SCR nozzle.

4. An engine cooling circulation system according to claim 3, Features: It also includes a urea tank heating circuit for heating the urea tank. The urea tank heating circuit starts from a urea tank heating interface connected to a cylinder coolant circuit, passes through the urea tank, and then returns to a water inlet chamber of a water pump.

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