CN112922739A

CN112922739A - Engine and commercial car with exhaust gas recirculation system

Info

Publication number: CN112922739A
Application number: CN202110348926.XA
Authority: CN
Inventors: 李智; 陈功军; 高磊; 王东; 欧阳凤霞; 王明秀
Original assignee: Dongfeng Commercial Vehicle Co Ltd
Current assignee: Dongfeng Commercial Vehicle Co Ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-06-08

Abstract

The invention discloses an engine with an exhaust gas recirculation system and a commercial vehicle, relating to the technical field of engines, wherein the engine comprises: an engine cylinder block, an engine cylinder head, and an EGR cooler; a plurality of engine cylinder water jackets are arranged in the engine cylinder body, and each engine cylinder water jacket is connected with a water inlet; an engine cylinder head water jacket is arranged in the engine cylinder head and comprises a plurality of first cylinder head upper water jackets positioned above one side of the engine cylinder head, a plurality of engine cylinder head lower water jackets positioned below the engine cylinder head and a plurality of second cylinder head upper water jackets positioned above the other side of the engine cylinder head; each engine cylinder water jacket corresponds to and is communicated with a first cylinder cover upper water jacket, an engine cylinder cover lower water jacket and a second cylinder cover upper water jacket in sequence; the EGR cooler is provided with an EGR cooling water jacket. The invention has high cooling water utilization rate and good cooling effect of the engine cylinder body and the EGR cooler.

Description

Engine and commercial car with exhaust gas recirculation system

Technical Field

The invention relates to the technical field of engines, in particular to an engine with an exhaust gas recirculation system and a commercial vehicle.

Background

Currently, water-cooled engines mainly include a cylinder block, a cylinder head, and a cylinder head gasket between the cylinder block and the cylinder head. The cylinder block and the upper crankcase are cast into a whole, and the cylinder block is called as a cylinder block-crankcase and can also be called as a cylinder block. The cylinder block of a water-cooled engine is generally cast by gray cast iron, the cylindrical cavity at the upper part of the cylinder block is called as a cylinder, the lower half part of the cylinder block is a crankcase for supporting a crankshaft, and the inner cavity of the cylinder block is a space for the crankshaft to move. A plurality of reinforcing ribs, a cooling water jacket, a lubricating oil channel and the like are cast in the cylinder block. The cylinder block has sufficient strength and rigidity, and is generally classified into the following three forms: general cylinder blocks, gantry cylinder blocks, and tunnel cylinder blocks. The general cylinder body has the characteristics that the oil pan mounting plane and the crankshaft rotation center are at the same height, and has the advantages of small height of a machine body, light weight, compact structure, convenience in processing and convenience in disassembly and assembly of the crankshaft, but has the defect of poor rigidity and strength. The gantry cylinder block is characterized in that the mounting plane of an oil pan is lower than the rotation center of a crankshaft. Its advantages are high strength and rigidity, and high mechanical load bearing capacity, but its disadvantages are poor manufacturability, heavy structure and difficult machining. The main bearing hole of the cylinder crankshaft of the tunnel type cylinder block is integral, a rolling bearing is adopted, the main bearing hole is large, the crankshaft is installed from the rear part of the cylinder block, and the tunnel type cylinder block has the advantages of compact structure, good rigidity and strength, but the tunnel type cylinder block has the defects of high processing precision requirement, poor manufacturability and inconvenient crankshaft assembly and disassembly. The cylinder head of a water-cooled engine, which is mounted on the upper surface of a cylinder block, seals the cylinder from the upper side and forms a combustion chamber, is often in contact with high-temperature and high-pressure combustion gas, and thus is subjected to a large thermal load and a large mechanical load. The cylinder cover is internally provided with a cooling water jacket, cooling water holes on the lower end surface of the cylinder cover are communicated with cooling water holes of the cylinder body, and circulating water is used for cooling high-temperature parts such as a combustion chamber. The cylinder head is generally cast by gray cast iron or alloy cast iron, and the aluminum alloy has good thermal conductivity and is beneficial to improving the compression ratio, so the aluminum alloy cylinder head is increasingly used in recent years. The cylinder gasket is arranged between the cylinder cover and the cylinder body, and has the function of ensuring the sealing of the contact surface of the cylinder cover and the cylinder body and preventing air leakage, water leakage and oil leakage. The cylinder gasket is made of a material having elasticity to compensate for unevenness of a joint surface to ensure sealing, and has good heat resistance and pressure resistance, and is free from burning loss and deformation at high temperature and high pressure.

With increasingly stringent engine emission requirements, engines with exhaust Gas recirculation (egr) systems are becoming more widely used, and exhaust Gas recirculation (egr) refers to the recirculation of a portion of the exhaust gases from an engine back into the intake manifold and back into the cylinder along with fresh mixture. Because the waste gas contains a large amount of CO₂Equal polyatomic gas, and CO₂When the gas is not combusted, the gas absorbs a large amount of heat due to its high specific heat capacity, so that the maximum combustion temperature of the air-fuel mixture in the cylinder is lowered, thereby reducing the amount of NOx generated and improving fuel economy at partial load.

In the related art, cooling is required before exhaust gas is reintroduced into the intake side of the engine, and if exhaust gas is not cooled, hot recirculated exhaust gas heats intake air, resulting in a large increase in-cylinder combustion temperature and pressure, which counteracts the effect of the EGR system in reducing nitrogen oxides, and in severe cases, also causes structural damage to the engine body, and therefore, it is necessary to cool high-temperature exhaust gas. For this reason, EGR systems are generally provided with an EGR cooler which can reduce the temperature of the exhaust gas entering the cylinders, a low temperature being beneficial for the thermal load of the engine, reducing the engine temperature. Therefore, the EGR cooler is provided with an EGR cooling water jacket, and mainly used to cool the exhaust gas after combustion and introduce the cooled exhaust gas to the engine intake side.

However, the conventional EGR cooling water jacket is connected in parallel with the cylinder water jacket, and therefore, the utilization rate of cooling water is low, and the cooling effect of the whole engine cylinder block and the EGR cooler is poor. In addition, the engine adopts the cooling water cocurrent flow mode to flow through the engine cylinder head (the cooling water directly flows out from the lower water jacket on the side of the engine cylinder head and upwards passes through the upper water jacket), and the cooling effect of the engine cylinder head is poor.

Disclosure of Invention

The embodiment of the invention provides an engine with an exhaust gas recirculation system and a commercial vehicle, and aims to solve the technical problems of low cooling water utilization rate and poor integral cooling effect of an engine cylinder body and an EGR cooler in the related technology.

In a first aspect, an engine having an exhaust gas recirculation system is provided, comprising:

the engine cylinder comprises an engine cylinder body, a water inlet, a water outlet and a water inlet, wherein a plurality of engine cylinder water jackets are arranged in the engine cylinder body, and each engine cylinder water jacket is used for being connected with one water inlet;

an engine cylinder head having an engine cylinder head water jacket disposed therein in communication with all of the engine cylinder water jackets, the engine cylinder head water jacket including a plurality of first cylinder head upper water jackets above one side of the engine cylinder head, a plurality of engine cylinder head lower water jackets below the engine cylinder head, and a plurality of second cylinder head upper water jackets above another side of the engine cylinder head; each engine cylinder water jacket corresponds to and is communicated with one first cylinder cover upper water jacket, one engine cylinder cover lower water jacket and one second cylinder cover upper water jacket in sequence;

the EGR cooler is provided with an EGR cooling water jacket communicated with the water jacket on the second cylinder cover, and the EGR cooling water jacket is used for being connected with a water outlet.

The engine reduces the requirement of the engine on the flow of cooling water by connecting the EGR cooling water jacket with the water jacket on the second cylinder cover in series, improves the utilization rate of the cooling water, and has good integral cooling effect of the engine cylinder body and the EGR cooler. And cooling water sequentially flows through the first cylinder cover upper water jacket, the engine cylinder cover lower water jacket positioned on the other side of the engine cylinder cover and the second cylinder cover upper water jacket to cool a thermal key area in the middle of the engine cylinder cover, so that the working temperature of the engine cylinder cover is effectively reduced, and the thermal fatigue resistance of the engine cylinder cover is improved.

In some embodiments, the EGR cooler is fixed to the side of the engine cylinder head, and at least one joint extends from a side of the EGR cooling water jacket adjacent to the engine cylinder head, each joint communicating with the second cylinder head upper water jacket.

At least one of the joints extends from a side of the EGR cooling water jacket adjacent to the engine cylinder head. The EGR cooler is integrated on the side surface of the engine cylinder head and is provided with the EGR cooling water jacket which is directly communicated with the engine cylinder head water jacket group, so that the process of connecting the EGR cooler with an engine cooling system by additionally assembling a cooling water pipeline is omitted, and the labor cost and the time cost are reduced.

In some embodiments, the second cylinder head upper water jacket is in communication with the water outlet.

And the water jacket on the second cylinder cover is communicated with the water outlet, and a drainage channel is additionally arranged, so that the resistance of the system is reduced.

In some embodiments, a throttle valve is disposed between the water jacket on the second cylinder head and the water outlet.

And a throttle valve is arranged between the water jacket on the second cylinder cover and the water outlet. The throttle valve can adjust the water amount entering the EGR cooling water jacket to meet different cooling water amount requirements of the EGR cooling water jacket.

In some embodiments, a plurality of injector mounting holes corresponding to the water jackets on the first cylinder head in a one-to-one manner are formed in the center line of the engine cylinder head, and an annular gap is formed around each injector mounting hole and communicates the corresponding water jackets on the first cylinder head with the lower water jacket of the engine cylinder head.

The annular gaps are arranged around the oil sprayer mounting holes and communicate the corresponding first cylinder cover upper water jacket with the engine cylinder cover lower water jacket, so that the structure is simple and compact, and the communication function of the first cylinder cover upper water jacket and the engine cylinder cover lower water jacket is realized. The annular gap also enables cooling water to form impact jet flow on structures such as the fuel injector mounting hole in the middle, the water flow speed of the thermal key area in the middle is greatly improved, and the cooling strength of the thermal key area in the middle is enhanced.

In some embodiments, a plurality of the second cylinder head upper water jackets are communicated in sequence to form an integral water jacket.

The integral water jacket is formed by communicating a plurality of the second cylinder head upper water jackets, so that the water of the second cylinder head upper water jacket can enter the EGR cooling water jacket conveniently.

In some embodiments, the water jackets of the engine cylinders, the water jackets of the first cylinder heads, or the water jackets of the engine cylinder heads are independent of one another.

The engine cylinder water jackets, the first cylinder cover upper water jackets and the engine cylinder cover lower water jackets are all set to be mutually independent water jackets, so that each engine cylinder block corresponds to one engine cylinder water jacket, one first cylinder cover upper water jacket and one engine cylinder cover lower water jacket, and the heat dissipation effect of each engine cylinder block is ensured to be consistent.

In some embodiments, the engine with an exhaust gas recirculation system further comprises:

and the water pump is arranged on the engine cylinder body and is communicated with all the water inlets.

Through setting up the water pump, the water pump with all the water inlet intercommunication provides the cooling water for a plurality of engine cylinder water jackets of engine cylinder block inside.

In some embodiments, the EGR cooler is made of aluminum material, which has good heat dissipation effect.

In a second aspect, a commercial vehicle is provided, comprising the engine with an exhaust gas recirculation system of the above embodiment.

The engine of the commercial vehicle reduces the requirement of the engine on the flow of cooling water and improves the utilization rate of the cooling water by connecting the EGR cooling water jacket with the water jacket on the second cylinder cover in series, and the engine cylinder body and the EGR cooler have good integral cooling effect. In addition, cooling water sequentially flows through the first cylinder head upper water jacket, the engine cylinder head lower water jacket positioned on the other side of the engine cylinder head and the second cylinder head upper water jacket to cool a thermal key area in the middle of the engine cylinder head, so that the working temperature of the engine cylinder head is effectively reduced, and the thermal fatigue resistance of the engine cylinder head is improved.

The technical scheme provided by the invention has the beneficial effects that:

the embodiment of the invention provides an engine with an exhaust gas recirculation system and a commercial vehicle, wherein an EGR cooling water jacket is connected with a water jacket on a second cylinder cover in series, so that the engine cylinder water jacket, the water jacket on the cylinder cover of the engine and the water jacket of an EGR cooler are connected in series, the requirement of the engine on the flow rate of cooling water is reduced, the utilization rate of the cooling water is improved, and the integral cooling effect of an engine cylinder body and the EGR cooler is good. In addition, cooling water sequentially flows through the first cylinder head upper water jacket, the engine cylinder head lower water jacket positioned on the other side of the engine cylinder head and the second cylinder head upper water jacket to cool a thermal key area in the middle of the engine cylinder head, so that the working temperature of the engine cylinder head is effectively reduced, and the thermal fatigue resistance of the engine cylinder head is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic block diagram of an engine having an exhaust gas recirculation system according to an embodiment of the present disclosure;

FIG. 2 is a view taken along line A-A of FIG. 1;

FIG. 3 is a schematic diagram of an engine having an exhaust gas recirculation system according to an embodiment of the present disclosure;

in the figure: 1. an engine cylinder block; 11. an engine cylinder water jacket; 2. an engine cylinder head; 21. a water jacket is arranged on the first cylinder cover; 22. a lower water jacket of an engine cylinder head; 23. a water jacket is arranged on the second cylinder cover; 24. a fuel injector mounting hole; 25. an annular gap; 3. an EGR cooler; 31. an EGR cooling water jacket; 311. a joint; 4. a water inlet; 5. a water outlet; 6. a throttle valve.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

The embodiment of the invention provides an engine with an exhaust gas recirculation system, which can solve the technical problems of low cooling water utilization rate and poor integral cooling effect of an engine cylinder body and an EGR cooler in the related art.

Referring to fig. 1 and 2, an engine having an exhaust gas recirculation system includes: an engine block 1, an engine cylinder head 2, and an EGR cooler 3.

A plurality of engine cylinder water jackets 11 are arranged in the engine cylinder block 1, and each engine cylinder water jacket 11 is used for connecting a water inlet 4.

An engine cylinder head water jacket set communicated with all the engine cylinder water jackets 11 is arranged inside the engine cylinder head 2, and comprises a plurality of first cylinder head upper water jackets 21 positioned above one side of the engine cylinder head 2, a plurality of engine cylinder head lower water jackets 22 positioned below the engine cylinder head 2, and a plurality of second cylinder head upper water jackets 23 positioned above the other side of the engine cylinder head 2; each of the engine cylinder water jackets 11 corresponds to and communicates with one of the first cylinder head upper water jackets 21, one of the engine cylinder head lower water jackets 22, and one of the second cylinder head upper water jackets 23 in this order.

The EGR cooler 3 is provided with an EGR cooling water jacket 31 communicating with the second head upper water jacket 23, and the EGR cooling water jacket 31 is connected with a water outlet 5.

In the engine with the exhaust gas recirculation system according to the embodiment of the present invention, the EGR cooling water jacket 31 is connected in series with the second cylinder head upper water jacket 23, so that the demand of the engine on the flow rate of the cooling water is reduced, the utilization rate of the cooling water is improved, and the cooling effect of the whole engine cylinder block 1 and the EGR cooler 3 is good. In addition, the cooling water flows through the first cylinder head upper water jacket 21, the engine cylinder head lower water jacket 22 and the second cylinder head upper water jacket 23 which are positioned on the other side of the engine cylinder head 2 in sequence to cool a thermal critical area in the middle of the engine cylinder head 2, so that the working temperature of the engine cylinder head 2 is effectively reduced, and the thermal fatigue resistance of the engine cylinder head 2 is improved.

Example 2

On the basis of the embodiment 1, as an optional implementation mode: the EGR cooler 3 is fixed on the side surface of the engine cylinder head 2, and at least one joint 311 extends from one side of the EGR cooling water jacket 31 close to the engine cylinder head 2, and each joint 311 is communicated with the engine cylinder head water jacket group. In the engine with an exhaust gas recirculation system in the embodiment of the present invention, two joints 311 extend from one side of the EGR cooling water jacket 31 close to the cylinder head 2 of the engine. The EGR cooler 3 is integrated on the side surface of the engine cylinder head 2, the EGR cooler 3 is provided with the EGR cooling water jacket 31, the EGR cooling water jacket 31 is directly communicated with the engine cylinder head water jacket group, the process that a cooling water pipeline is additionally assembled to connect the EGR cooler 3 with an engine cooling system is omitted, and labor and time costs are reduced.

Example 3

On the basis of the embodiment 1, as an optional implementation mode: referring to fig. 2, the second cylinder head upper water jacket 23 is communicated with the water outlet 5, and a drain passage is additionally arranged, so that the system resistance is reduced.

Example 4

On the basis of the embodiment 3, as an optional implementation mode: referring to fig. 2, a throttle valve 6 is arranged between the second cylinder head upper water jacket 23 and the water outlet 5, and the throttle valve 6 can adjust the water amount entering the EGR cooling water jacket 31 to meet different cooling water amount requirements of the EGR cooling water jacket 31. Since one path of the second cylinder head upper water jacket 23 is connected with the water outlet and the other path is connected with the EGR cooling water jacket 31, when the flow rate of cooling water entering the water outlet is controlled, the water amount entering the EGR cooling water jacket 31 can be adjusted. The throttle valve is a valve for controlling the flow of fluid by changing the throttle section or the throttle length. Preferably, a throttle valve and a check valve may be combined in parallel to form a check throttle valve, and both the throttle valve and the check valve are simple flow control valves that can control the amount of water entering the EGR cooling water jacket 31.

Example 5

On the basis of the embodiment 1, as an optional implementation mode: referring to fig. 1, a plurality of injector mounting holes 24 corresponding to the first cylinder head upper water jacket 21 in a one-to-one manner are formed in a center line of the engine cylinder head 2, an annular gap 25 is formed around each injector mounting hole 24, and the corresponding first cylinder head upper water jacket 21 and the engine cylinder head lower water jacket 22 are communicated through the annular gap 25, so that the structure is simple and compact, and the communication function of the first cylinder head upper water jacket 21 and the engine cylinder head lower water jacket 22 is realized. The annular gap 25 enables cooling water to form impact jet flow on structures such as the fuel injector mounting hole 24 in the middle, the water flow speed of a thermal key area in the middle is greatly improved, and the cooling strength of the thermal key area in the middle is enhanced. The injector mounting hole 24 is used for mounting an injector, which is an important part for realizing fuel injection in a diesel engine fuel supply system, and has a function of atomizing fuel into fine oil droplets according to the characteristics of diesel engine mixed gas formation and injecting the fine oil droplets to a specific part of a combustion chamber. The fuel injector can be understood as a simple electromagnetic valve, when an electromagnetic coil is electrified, suction force is generated, a needle valve is sucked up, a spray hole is opened, and fuel is sprayed out at a high speed through an annular gap between a pintle of a needle valve head and the spray hole to form fog, so that sufficient combustion is facilitated. When the vehicle Electronic Control Unit (ECU) issues an injection command, the voltage signal will make current flow through the coil in the injection nozzle to generate a magnetic field to suck the valve needle up, so that the valve is opened to spray the oil from the injection hole. The biggest advantage of fuel injection is that the fuel supply is controlled very accurately, so that the engine can have correct air-fuel ratio in any state, the engine can be operated smoothly, and the waste gas of the engine can meet the standard of environmental protection regulations.

Example 6

On the basis of the embodiment 1, as an optional implementation mode: the plurality of second cylinder head upper water jackets 23 are sequentially communicated to form an integral water jacket, so that water of the second cylinder head upper water jacket 23 can enter the EGR cooling water jacket 31. Referring to fig. 2, the engine with an exhaust gas recirculation system in the embodiment of the present invention is a 6-cylinder engine, that is, 6 second cylinder head water jackets 23 are provided, and the 6 second cylinder head water jackets 23 are sequentially communicated to form an integral water jacket. After the plurality of second cylinder head upper water jackets 23 form an integral water jacket, the collected cooling water enters the EGR cooling water jacket 31 through the two joints 311 extending from the side of the EGR cooling water jacket 31 close to the engine cylinder head 2, and cools the exhaust gas flowing through the EGR cooler 3.

Example 7

On the basis of the embodiment 2, as an optional implementation mode: the engine cylinder water jackets 11, the first cylinder cover upper water jackets 21 and the engine cylinder cover lower water jackets 22 are independent water jackets, which is equivalent to that each engine cylinder block 1 corresponds to one engine cylinder water jacket 11, one first cylinder cover upper water jacket 21 and one engine cylinder cover lower water jacket 22, so that the heat dissipation effect of each engine cylinder block 1 is ensured to be consistent, and the service life of the engine is prolonged. Referring to fig. 2, in the engine with an exhaust gas recirculation system according to the embodiment of the present invention, there are independent water jackets between 6 of the water jackets 21 on the first cylinder head.

Example 8

On the basis of embodiment 1, as an alternative implementation manner, the engine with an exhaust gas recirculation system in the embodiment of the present invention further includes: and the water pump is arranged on the engine cylinder body 1 and is communicated with all the water inlets 4. The water pump communicates with all of the water inlets 4 to provide cooling water to a plurality of engine cylinder water jackets 11 inside the engine block 1.

The engine widely adopts a centrifugal water pump, and the basic structure of the centrifugal water pump comprises parts such as a water pump shell, a connecting disc or a belt pulley, a water pump shaft and a bearing, a water pump impeller, a water seal device and the like. The engine drives the water pump bearing and the impeller to rotate through the belt pulley, the cooling water in the water pump is driven by the impeller to rotate together, is thrown to the edge of the water pump shell under the action of centrifugal force, generates certain pressure at the same time, and then flows out of the water outlet channel or the water pipe. The pressure of the center of the impeller is reduced because the cooling water is thrown out, and the cooling water is sucked into the impeller through the water pipe under the action of the pressure difference between the inlet of the water pump and the center of the impeller, so that the reciprocating circulation of the cooling water is realized. The water pump housing is typically connected to the engine by a gasket and supports moving parts such as bearings. Since the bearing supporting the water pump shaft is lubricated with grease, the grease is prevented from being emulsified by the leakage of cooling water into the grease, and the leakage of the grease is also prevented. The water pump has water seal and sealing gasket. The water seal dynamic sealing ring and the shaft are arranged between the impeller and the bearing in an interference fit manner, and the water seal static sealing seat is tightly pressed on a shell of the water pump, so that the purpose of sealing cooling water is achieved. The centrifugal pump has simple and compact structure, small occupied area for the same conveying capacity, light weight, less material consumption and high-speed operation.

Example 9

On the basis of the embodiment 1, as an optional implementation mode: the EGR cooler 3 is made of aluminum materials, has good heat dissipation effect, can reduce the temperature of exhaust gas entering a cylinder, and has low temperature which is beneficial to the heat load of an engine.

Example 10

The embodiment of the invention provides a commercial vehicle which comprises the engine with the exhaust gas recirculation system in the embodiment, the commercial vehicle in the embodiment of the invention has the advantages that the EGR cooling water jacket 31 is connected with the second cylinder head upper water jacket 23 in series, the requirement of the engine on the flow rate of cooling water is reduced, the utilization rate of the cooling water is improved, and the integral cooling effect of the engine cylinder block 1 and the EGR cooler 3 is good. In addition, the cooling water flows through the first cylinder head upper water jacket 21, the engine cylinder head lower water jacket 22 and the second cylinder head upper water jacket 23 which are positioned on the other side of the engine cylinder head 2 in sequence to cool a thermal critical area in the middle of the engine cylinder head 2, so that the working temperature of the engine cylinder head 2 is effectively reduced, and the thermal fatigue resistance of the engine cylinder head 2 is improved.

The engine with the exhaust gas recirculation system in the embodiment of the invention has the following working principle:

the cooling water enters the engine cylinder water jacket 11 from the water inlet 4, and flows from one side of the cylinder to the other side of the cylinder to take heat away from the cylinder, as shown in fig. 1. A first cylinder cover upper water jacket 21 is arranged in the engine cylinder cover 2 above one side, far away from the water inlet 4, of each engine cylinder water jacket 11, each engine cylinder water jacket 11 is communicated with one corresponding first cylinder cover upper water jacket 21, and cooling water continues to flow and enters the first cylinder cover upper water jacket 21. An engine cylinder head lower water jacket 22 is arranged in the engine cylinder head 2 above the water inlet 4, the first cylinder head upper water jacket 21 is communicated with the engine cylinder head lower water jacket 22 through the annular gap 25, cooling water enters the engine cylinder head lower water jacket 22 from the first cylinder head upper water jacket 21, a second cylinder head upper water jacket 23 is arranged in the engine cylinder head 2 above the engine cylinder head lower water jacket 22, the second cylinder head upper water jacket 23 is communicated with the engine cylinder head lower water jacket 22, the cooling water enters the engine cylinder head lower water jacket 22 from the second cylinder head upper water jacket 23, the plurality of second cylinder head upper water jackets 23 are communicated in sequence to form an integral water jacket, the EGR cooler 3 is fixed on the side surface of the engine cylinder head 2, and two joints 311 extend from one side of the EGR cooling water jacket 31 close to the engine cylinder head 2, each joint 311 is communicated with the integral water jacket, and cooling water enters the EGR cooling water jacket 31 from the integral water jacket and finally flows out through the water outlet 5. The cooling water achieves both cooling of the engine block 1 and the engine cylinder head 2 and cooling of the EGR cooler 3.

It should be noted that the engine cylinder water jacket 11, the first cylinder head upper water jacket 21, the engine cylinder head lower water jacket 22, and the second cylinder head upper water jacket 23, which are cavities between the engine cylinder block 1 and the inner and outer casings of the engine cylinder head 2, are equivalent to porous water outlet pipes, and when cooling water circulates from the water tank to reach the engine, if there is only one water outlet, the cooling effect is relatively concentrated, the effect is better at a place close to the water outlet, the effect is certainly worse at a place far away, and the average service life of the engine is unfavorable for a long time. Therefore, the cooling water flows out from the plurality of holes, so that the cooling effect of the whole engine is relatively balanced, and the service life of the engine is prolonged.

In addition, referring to fig. 1, each of the engine cylinder water jackets 11 surrounds the outer periphery of one of the cylinders, and the outer periphery of the cylinder is sufficiently cooled. The cavity structures of the first cylinder head upper water jacket 21 and the engine cylinder head lower water jacket 22 close to the corresponding fuel injector mounting hole 24 are all surrounded on the periphery of the corresponding fuel injector mounting hole 24, and the flow of cooling water is realized by utilizing a compact structure.

In the description of the present invention, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

It is to be noted that, in the present invention, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An engine having an exhaust gas recirculation system, comprising:

the engine comprises an engine cylinder block (1), wherein a plurality of engine cylinder water jackets (11) are arranged in the engine cylinder block (1), and each engine cylinder water jacket (11) is connected with a water inlet (4);

an engine cylinder head (2), an engine cylinder head water jacket set communicated with all the engine cylinder water jackets (11) is arranged in the engine cylinder head (2), and the engine cylinder head water jacket set comprises a plurality of first cylinder head upper water jackets (21) positioned above one side of the engine cylinder head (2), a plurality of engine cylinder head lower water jackets (22) positioned below the engine cylinder head (2) and a plurality of second cylinder head upper water jackets (23) positioned above the other side of the engine cylinder head (2); each engine cylinder water jacket (11) corresponds to and is communicated with one first cylinder cover upper water jacket (21), one engine cylinder cover lower water jacket (22) and one second cylinder cover upper water jacket (23) in sequence;

the EGR cooler (3), the EGR cooling water jacket (31) that is equipped with inside the EGR cooler (3) and communicates with the second cylinder head upper water jacket (23), a delivery port (5) is connected to EGR cooling water jacket (31).

2. An engine having an exhaust gas recirculation system according to claim 1, wherein:

the EGR cooler (3) is fixed on the side surface of the engine cylinder cover (2), at least one joint (311) extends from one side of the EGR cooling water jacket (31) close to the engine cylinder cover (2), and each joint (311) is communicated with the second cylinder cover upper water jacket (23).

3. An engine having an exhaust gas recirculation system according to claim 1, wherein:

the second cylinder cover upper water jacket (23) is communicated with the water outlet (5).

4. An engine having an exhaust gas recirculation system according to claim 3, wherein:

and a throttle valve (6) is arranged between the second cylinder cover upper water jacket (23) and the water outlet (5).

5. An engine having an exhaust gas recirculation system according to claim 1, wherein:

the engine cylinder head (2) is characterized in that a plurality of fuel injector mounting holes (24) which correspond to the first cylinder head upper water jackets (21) in a one-to-one mode are formed in the center line of the engine cylinder head (2), an annular gap (25) is formed around each fuel injector mounting hole (24), and the corresponding first cylinder head upper water jackets (21) are communicated with the engine cylinder head lower water jackets (22) through the annular gaps (25).

6. An engine having an exhaust gas recirculation system according to claim 1, wherein:

and a plurality of second cylinder cover upper water jackets (23) are communicated in sequence to form an integral water jacket.

7. An engine having an exhaust gas recirculation system according to claim 1, wherein:

the water jackets among the plurality of engine cylinder water jackets (11), the plurality of first cylinder head upper water jackets (21) or the plurality of engine cylinder head lower water jackets (22) are mutually independent water jackets.

8. An engine having an exhaust gas recirculation system according to claim 1, further comprising:

the water pump is arranged on the engine cylinder body (1) and is communicated with all the water inlets (4).

9. An engine having an exhaust gas recirculation system according to claim 1, wherein: the EGR cooler (3) is made of an aluminum material.

10. A commercial vehicle comprising an engine with an exhaust gas recirculation system according to any one of claims 1 to 9.