CN105422247A - Intelligent cooling system based on split cooling and reverse cooling for engine, and control method - Google Patents

Abstract

The invention discloses an intelligent cooling system based on split cooling and reverse cooling for an engine, and a control method. The cooling system comprises a cylinder cover water jacket, a body water jacket, an electronically-controlled water pump, electronic thermostats, an electronically-controlled fan, a heat dissipater, an expansion water tank, temperature sensors, motors and an electronic control unit. During a working process of the system, the electronically-controlled water pump pumps a cooling liquid in the engine, the first electronic thermostat controls the cooling liquid to enter the cylinder cover water jacket and the body water jacket according to cooling liquid temperature signals of a cylinder cover and a body respectively, flow from top down, and flow out after the cooling the cylinder cover and the body; and the second electronic thermostat distributes the flow rate of the cooling liquid entering large circulation and small circulation according to a cooling liquid temperature of a main tube, and the cooling liquid is circulated and then pumped in the engine to cool. The cooling system disclosed by the invention is capable of accurately distributing the flow rate of the cooling liquid in the cylinder body and the body of the engine, reducing the phenomenon of non-uniform cooling, and shortening the warm-up time of the engine; and the heat states of heated components are optimized through the reverse cooling.

Description

An engine intelligent cooling system and control method based on split cooling and reverse cooling

technical field

The invention relates to an engine intelligent cooling system and a control method, in particular to an engine intelligent cooling system combined with cylinder head body split cooling technology and reverse cooling technology

Background technique

As the power density of diesel engines and the explosion pressure in the cylinder continue to increase, the thermal load of heated parts including cylinder heads and cylinder liners continues to increase, and the number of thermal failure cases is gradually increasing. At the same time, the direction of energy saving and emission reduction of diesel engines is The general trend. Therefore, the continuous development of diesel engines puts forward stricter requirements on its reliability, fuel economy and emission performance. Therefore, the cooling system should provide sufficient cooling strength for the high heat load area to ensure its thermal reliability, and at the same time reduce the heat load area. Cooling flow in low zones avoids wasted cooling effort, thereby improving fuel economy.

In the traditional cooling system, an integrated water jacket is adopted for the cooling of the cylinder head and the cylinder liner. The heat load is higher than that of the cylinder liner. This cooling method cannot independently adjust the cooling intensity of the cylinder head and cylinder liner, so it will cause insufficient cooling of the cylinder head or excessive cooling of the cylinder liner. At the same time, the coolant first cools the cylinder liner and then cools the cylinder head, which will inevitably cause the temperature of the cylinder head water jacket coolant to be higher than that of the cylinder liner water jacket coolant, which is not conducive to the reasonable regulation of the cooling intensity of the cylinder head and cylinder liner.

Therefore, according to the different cooling requirements of the cylinder head and cylinder liner, the separate cooling technology of the cylinder head body has been studied: separate cooling circuits are used for the cylinder head and the body respectively, and the flow rate of each cooling circuit can be independently adjusted to achieve " Precise Cooling". Studies have shown that the use of split cooling and reasonable distribution of cooling flow can properly reduce the average temperature of the cylinder head and increase the average temperature of the cylinder liner, reduce the heat dissipation of the cooling liquid of the whole machine and the power consumption of the water jacket, and reduce the friction coefficient of the cylinder liner-piston to improve Fuel economy; at the same time, the use of split cooling can shorten the engine warm-up time and improve emission performance. On the other hand, the use of reverse cooling technology can improve the thermal reliability of heated parts by increasing the cooling intensity of key areas, reducing the thermal stress on the fire surface of the cylinder head bottom plate.

Therefore, it is of great benefit to propose an intelligent cooling system based on the combined application of cylinder head-body split cooling technology and reverse cooling technology to improve the performance of the engine.

Contents of the invention

The purpose of the invention is to propose a model of engine intelligent cooling system based on split cooling and reverse cooling.

An engine intelligent cooling system based on engine split cooling and reverse cooling includes an electronically controlled water pump, a first electronically controlled thermostat, a second electronically controlled thermostat, an electronically controlled fan, an expansion tank, a cylinder head water jacket, and an engine body water jacket, first temperature sensor, second temperature sensor, third temperature sensor, first motor, second motor and electronic control unit,

The electronically controlled water pump and the first electronically controlled thermostat are arranged on the cylinder head water jacket and the front end of the body water jacket, and are installed on the engine body; the cylinder head and the rear end of the body water jacket are equipped with a second electronically controlled thermostat , the second electronically controlled thermostat is installed on the engine cylinder head, the first outlet of the second electronically controlled thermostat is directly connected to the electronically controlled water pump through a pipe, the second outlet is divided into two coolant pipes, and one coolant pipe passes through The radiator is connected to the electronically controlled water pump, and the other coolant pipe is connected to the electronically controlled water pump after passing through the expansion tank. The electronically controlled fan is used to provide forced convection heat exchange for the radiator. The first motor drives the electronically controlled fan, and the second motor drives the electronically controlled water pump. , the first temperature sensor is installed at the inlet of the cylinder head water jacket, the second temperature sensor is installed at the inlet of the body water jacket, the third temperature sensor is installed at the inlet of the second electronically controlled thermostat, the electronic control unit is connected with all temperature sensors, electric The thermostat is connected to the motor.

In the cylinder head water jacket and body water jacket, the coolant flow direction is from top to bottom.

The cylinder head and engine block are cooled by separate water jackets.

The first outlet of the first electronically controlled thermostat is connected to the water jacket of the cylinder head, and the second outlet is connected to the water jacket of the body.

The third temperature sensor is installed behind the junction of the outlet pipes of the water jacket of the cylinder head and the water jacket of the machine body.

The invention also discloses a cooling flow matching control method of the engine intelligent cooling system:

During the normal operation of the diesel engine, the second motor drives the cooling water pump to pump the coolant into the cooling channel inside the engine. Through the first electronically controlled thermostat, the electronic control unit adjusts the temperature according to the water temperature data collected by the first and second temperature sensors. The opening degree of the first electronically controlled thermostat, so as to distribute the coolant flow into the water jacket of the cylinder head and the water jacket of the body;

After the coolant enters the water jacket of the cylinder head and the water jacket of the body, it flows in from the upper coolant inlet of the cylinder head and the body respectively, cools the heated parts from top to bottom, and then flows out from the water outlet of the cylinder head and the body respectively, two-way cooling The liquid meets in front of the second electronically controlled thermostat, and the electronic control unit adjusts the opening degree of the third electronically controlled thermostat according to the water temperature data collected by the third temperature sensor, thereby distributing the coolant entering the first outlet and the second outlet The flow rate is large, the coolant entering the first outlet directly enters the electronically controlled water pump, forming a small cycle; while the coolant entering the second outlet passes through the radiator, and the electronic fan driven by the first motor provides forced water-air convection heat exchange for it After lowering the coolant temperature, the coolant enters the electronically controlled cooling water pump to form a large cycle. During this process, the electronic control unit adjusts the motor speed according to the water temperature signal provided by the third temperature sensor, thereby controlling the speed of the electronic fan and the electronic water pump. ,

When the water temperature of the second outlet of the second electronically controlled thermostat is too high and the water pressure is too high, which is higher than the water pressure of the expansion tank, the coolant will automatically flow into the expansion tank for water storage; when the water pressure at the inlet of the electronically controlled water pump is lower than the water pressure of the expansion tank , the coolant automatically flows out of the expansion tank and flows into the electronically controlled water pump for replenishment.

The invention also discloses a cooling flow matching control method in the cold start process of the engine intelligent cooling system:

During the cold start process of the diesel engine, since the temperature rise of the cylinder liner is slower than that of the cylinder head, at the beginning of the warm-up period, before the coolant temperature reaches a preset limit value T _b , the first electronically controlled thermostat closes the cylinder liner water jacket At the inlet, the coolant is completely pumped into the water jacket of the cylinder head. After cooling the cylinder head, it enters the first outlet through the second electronically controlled thermostat, that is, directly enters the water pump 1 to form a small circulation loop. In this loop, the coolant is continuously received by the cylinder head Heating, when the temperature of the coolant rises to the preset limit value T _b , the first electronically controlled thermostat opens the inlet of the cylinder jacket water jacket, and configures the flow rate of the cylinder head water jacket and the body water jacket according to the instructions of the electronic control unit. The coolant in the body water jacket cools the cylinder head and cylinder liner separately and then joins the second electronically controlled thermostat. Before the temperature of the coolant reaches the preset limit value _Tc , the second electronically controlled thermostat still closes the second outlet. , the coolant passes through the water pump to form a small circulation loop, and the coolant is heated by the cylinder head and the cylinder liner at the same time in this loop, until the temperature of the coolant rises to the preset limit value T _c , the second electronically controlled thermostat opens the second outlet , the coolant enters the water pump after passing through the radiator, and the warm-up process ends.

The present invention has the following advantages:

1. The cooling system can independently regulate the cooling flow of the cylinder head water jacket and the body water jacket, reduce over-cooling phenomenon, and improve the fuel economy of the diesel engine;

2. During the cold start process, the cooling system can adjust the coolant flow of the cylinder head water jacket and the body water jacket in real time and independently through the ECU control, thereby reducing the warm-up time and reducing emissions;

3. In this cooling system, the cylinder head water jacket and the coolant in the cylinder jacket water jacket flow from top to bottom, which can improve the cooling strength of key areas, reduce thermal stress, and improve the thermal reliability of heated parts.

Description of drawings

Fig. 1 is a schematic diagram of the cooling system;

Fig. 2 is a schematic diagram of the cooling system control part;

Fig. 3 is a schematic diagram of the coolant flow inside the cylinder head water jacket and the cylinder jacket water jacket.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings, but not as a limitation of the present invention.

This cooling system model mainly includes the internal cooling water jacket (cylinder head, body cooling water jacket), external cooling system accessories (electrically controlled water pump, electronically controlled fan, electronically controlled thermostat, expansion tank) and electronic control part (ECU ,Temperature Sensor)

As shown in Figure 1, an engine intelligent cooling system based on engine split cooling and reverse cooling includes an electronically controlled water pump, a first electronically controlled thermostat, a second electronically controlled thermostat, an electronically controlled fan, an expansion tank, cylinder head water jacket, body water jacket, first temperature sensor, second temperature sensor, third temperature sensor, first motor, second motor and electronic control unit,

The electronically controlled water pump 1 and the first electronically controlled thermostat 2 are arranged at the front ends of the cylinder head water jacket 8 and the body water jacket 9, and are installed on the engine body 7; The electronically controlled thermostat 10, the second electronically controlled thermostat 10 is installed on the engine cylinder head 6, the first outlet of the second electronically controlled thermostat 10 is directly connected to the electronically controlled water pump 1 through a pipeline, and the second outlet is divided into two Two coolant pipes, one coolant pipe is connected to the electric control water pump 1 through the radiator 12, the other coolant pipe is connected to the electric control water pump 1 after passing through the expansion tank 16, and the electric control fan 13 is used to provide forced convection heat exchange to the radiator 12 , the first motor 14 drives the electronically controlled fan 13, the second motor 15 drives the electronically controlled water pump 1, the first temperature sensor 3 is installed at the inlet of the cylinder head water jacket, the second temperature sensor 4 is installed at the inlet of the body water jacket, and the third temperature sensor 5 is installed at the entrance of the second electronically controlled thermostat 10, and the electronic control unit 11 is connected with all temperature sensors, electronically controlled thermostats and motors.

In the water jacket 8 of the cylinder head and the water jacket 9 of the body, the flow direction of the coolant is from top to bottom.

The cylinder head and engine block are cooled by separate water jackets.

The first outlet of the first electronically controlled thermostat 2 is connected to the cylinder head water jacket 8, the second outlet is connected to the body water jacket 9, and the water outlet pipes of the cylinder head water jacket 8 and the body water jacket 9 are connected to the second electronically controlled thermostat 10 ago.

The third temperature sensor 5 is installed behind the junction of the water outlet pipes of the cylinder head water jacket 8 and the body water jacket 9 .

The invention also discloses a cooling flow matching control method of the engine intelligent cooling system:

During the normal operation of the diesel engine, the second motor 15 drives the cooling water pump 1 to pump the coolant into the cooling channel inside the engine. Through the first electronically controlled thermostat 2, the electronic control unit 11 collects the temperature according to the first and second temperature sensors. The water temperature data adjusts the opening of the first electronically controlled thermostat 2, thereby distributing the coolant flow into the cylinder head water jacket and the body water jacket; the electronic control unit 11 compares the signal of the first temperature sensor 3 with the cylinder head water jacket coolant flow The temperature preset target value T _H , while comparing the signal of the second temperature sensor 4 with the target value of the body water jacket coolant temperature T _L , read and output the opening degree signal of the electronically controlled thermostat 2 through the MAP map, and then control.

After the coolant enters the water jacket 6 of the cylinder head and the water jacket 7 of the body, it flows in from the upper coolant inlet of the cylinder head and the body respectively, and flows out from the water outlet of the cylinder head and the body after cooling the heated parts from top to bottom. The cooling liquid of the two circuits converges in front of the second electronically controlled thermostat 10, and the electronic control unit 11 adjusts the opening degree of the third electronically controlled thermostat 10 according to the water temperature data collected by the third temperature sensor 5, thereby distributing the coolant into the first outlet and The coolant flow rate of the second outlet is large, and the coolant entering the first outlet directly enters the electronically controlled water pump 1 to form a small cycle; the signal of the third temperature sensor 5 does not reach the temperature preset value T _c , and the electronic control unit 11 controls the third electronic The thermostat 5 closes the second outlet; if the signal from the third temperature sensor 5 reaches the temperature preset value T _c , but does not reach the thermostat full opening temperature preset value T _p , then the electronic control unit 11 controls the third electronic thermostat The sensor 5 opens the first and second outlets at the same time, and adjusts the opening of the two outlets according to the temperature data MAP value; if the signal of the third temperature sensor 5 reaches the preset value _Tp of the fully opened temperature of the thermostat, the electronic control unit 11 controls the first The three-electronic thermostat 5 closes the first outlet and fully opens the second outlet. The coolant entering the second outlet passes through the radiator 12, and the electronic fan 13 driven by the first motor 14 provides it with forced water-air convection heat exchange. After reducing the temperature of the coolant, the coolant enters the electronically controlled cooling water pump 1 to form Large cycle, in this process, the electronic control unit adjusts the rotation speed of the motor according to the water temperature signal provided by the third temperature sensor 5, thereby controlling the rotation speed of the electronic fan and the electronic water pump,

When the water temperature at the second outlet of the second electronically controlled thermostat 10 is too high and the water pressure is too high, which is higher than the water pressure of the expansion tank 16, the coolant will automatically flow into the expansion tank 16 for water storage; when the water pressure at the inlet of the electronically controlled water pump 1 is lower than Expansion water tank 16 hydraulic pressure, cooling liquid flows out expansion water tank 16 automatically and flows into electric control water pump 1 and replenishes water.

The invention also discloses a cooling flow matching control method in the cold start process of the engine intelligent cooling system:

During the cold start process of the diesel engine, since the temperature rise of the cylinder liner 7 is slower than that of the cylinder head 6, at the beginning of the warm-up period, before the coolant temperature reaches a certain preset limit value _Tb , the first electronically controlled thermostat 2 closes the cylinder The inlet of water jacket 9, the coolant is completely pumped into the water jacket 8 of the cylinder head, after cooling the cylinder head, it enters the first outlet through the second electronically controlled thermostat 10, that is, directly enters the water pump 1 to form a small circulation loop, and the coolant in this The circuit is continuously heated by the cylinder head, and when the temperature of the coolant rises to the preset limit value T _b , the first electronically controlled thermostat 2 opens the inlet of the cylinder jacket water jacket 9 and configures the cylinder head water jacket according to the instruction of the electronic control unit 11 and the flow rate of the body water jacket, the coolant in the cylinder head and the body water jacket respectively cools the cylinder head and the cylinder liner and joins the second electronically controlled thermostat 10. Before the temperature of the coolant reaches the preset limit value _Tc , the second The electronically controlled thermostat 10 still closes the second outlet, the coolant passes through the water pump 1 to form a small circulation loop, and the coolant is heated by the cylinder head and the cylinder liner at the same time in this loop until the temperature of the coolant rises to the preset limit value T _c , the second electronically controlled thermostat 10 opens the second outlet, the cooling liquid enters the water pump 1 after dissipating heat through the radiator 12, and the warm-up process ends.

As shown in Figure 2, during the working process of the intelligent cooling system, the first temperature sensor 3 and the second temperature sensor 4 respectively measure the water temperature signal of the water inlet of the cylinder head water jacket and the water temperature signal of the water inlet of the cylinder jacket water jacket, and the signals are transmitted to the electronic The control unit 11, the electronic control unit 11 controls the opening degree of the first electronic thermostat 2 according to the MAP map, so as to adjust the flow of coolant entering the cylinder head water jacket and the cylinder jacket water jacket. The third temperature sensor 5 measures the coolant temperature signal of the cylinder head water jacket and the body water jacket water outlet main pipe, and sends it to the electronic control unit 11. The electronic control unit 11 controls the opening degree of the second electronic thermostat 10 according to the MAP map, and adjusts the entry Coolant flow in large and small cycles; at the same time, the electronic control unit 11 controls the speed of the first motor 14 to control the cooling intensity of the cooling fan according to the temperature signal of the coolant in the water outlet main pipe, and controls the speed of the second motor 15 to control the electronically controlled water pump and then regulate the water entering the cylinder Total coolant flow for cover water jacket and body water jacket.

As shown in Figure 3, in order to achieve reverse cooling, the coolant flow direction is from top to bottom in the cylinder head water jacket and body water jacket. In the water jacket of the cylinder head, the coolant enters the water jacket from the upper inlet 1 of the water jacket to cool the heated area 2 such as the exhaust passage on the upper layer of the cylinder head, and then flows into the lower water jacket through the middle water jacket 3 to cool the high heat load such as the nose bridge area of the fire surface Area 4, which is collected at the outlet 5 of the water jacket of the cylinder head and flows out; in the water jacket of the body, the coolant enters the water jacket from the inlet 6 above the water jacket and partly flows around to cool the upper high heat load area 7. Flow up and down 8, and then gather at the cylinder jacket water jacket outlet 9 to flow out.

Claims (7)

1. An engine intelligent cooling system based on engine split cooling and reverse cooling, characterized in that it includes an electronically controlled water pump, a first electronically controlled thermostat, a second electronically controlled thermostat, an electronically controlled fan, an expansion tank, cylinder head water jacket, body water jacket, first temperature sensor, second temperature sensor, third temperature sensor, first motor, second motor and electronic control unit, The electronically controlled water pump (1) and the first electronically controlled thermostat (2) are arranged at the front ends of the cylinder head water jacket (8) and the body water jacket (9), and are installed on the engine body (7); the cylinder head , The rear end of the body water jacket is equipped with a second electronically controlled thermostat (10), which is installed on the engine cylinder head (6), and the second electronically controlled thermostat (10) The first outlet is directly connected to the electric control water pump (1) through a pipe, the second outlet is divided into two coolant pipes, one coolant pipe is connected to the electric control water pump (1) through the radiator (12), and the other coolant pipe is expanded The electric control water pump (1) is connected behind the water tank (16), and the electric control fan (13) is used to provide forced convection heat exchange to the radiator (12). The first motor (14) drives the electric control fan (13), and the second motor (15) Drive the electronically controlled water pump (1), the first temperature sensor (3) is installed at the inlet of the cylinder head water jacket, the second temperature sensor (4) is installed at the inlet of the body water jacket, and the third temperature sensor (5) is installed at the 2. The entrance of the electric control thermostat (10), the electronic control unit (11) is connected with all temperature sensors, electric control thermostat and motor. 2. The engine intelligent cooling system based on engine split cooling and reverse cooling according to claim 1, characterized in that in the cylinder head water jacket (8) and the body water jacket (9), the coolant flow directions are both top down. 3. The engine intelligent cooling system based on engine split cooling and reverse cooling according to claim 1, characterized in that the cylinder head and the body are cooled by independent water jackets. 4. The engine intelligent cooling system based on engine split cooling and reverse cooling according to claim 1, characterized in that the first outlet of the first electronically controlled thermostat (2) is connected to the cylinder head water jacket (8), The second outlet is connected to the body water jacket (9), and the water outlet pipes of the cylinder head water jacket (8) and the body water jacket (9) converge before the second electronically controlled thermostat (10). 5. The engine intelligent cooling system based on engine split cooling and reverse cooling according to claim 4, characterized in that the third temperature sensor (5) is installed on the cylinder head water jacket (8) and the body water jacket (9) after the confluence of the outlet pipes. 6. A cooling flow matching control method of an engine intelligent cooling system as claimed in claim 1, characterized in that: During the normal working process of the diesel engine, the second motor (15) drives the cooling water pump (1) to pump the coolant into the cooling channel inside the engine, and through the first electronically controlled thermostat (2), the electronic control unit (11) 1. The water temperature data collected by the second temperature sensor adjusts the opening of the first electronically controlled thermostat (2), thereby distributing the coolant flow into the cylinder head water jacket and the body water jacket; After the coolant enters the water jacket of the cylinder head (6) and the water jacket of the body (7), it flows in from the upper coolant inlet of the cylinder head and the body respectively, and cools the heated parts from top to bottom, and then exits from the cylinder head and the body respectively. The water outlet flows out, and the two cooling fluids meet in front of the second electronically controlled thermostat (10), and the electronic control unit (11) adjusts the third electronically controlled thermostat (10) according to the water temperature data collected by the third temperature sensor (5). ), so as to distribute the flow rate of the coolant entering the first outlet and the second outlet. The coolant entering the first outlet directly enters the electric control water pump (1) to form a small cycle; while the coolant entering the second outlet passes through The radiator (12), the electronic fan (13) driven by the first motor (14) provides it with forced water-air convection heat exchange, after reducing the temperature of the coolant, the coolant enters the electronically controlled cooling water pump (1), forming a large circulation, in this process, the electronic control unit adjusts the speed of the motor according to the water temperature signal provided by the third temperature sensor (5), thereby controlling the speed of the electronic fan and the electronic water pump, When the water temperature at the second outlet of the second electronically controlled thermostat (10) is too high and the water pressure is too high, which is higher than the water pressure of the expansion tank (16), the coolant will automatically flow into the expansion tank (16) for water storage; The inlet water pressure of the water pump (1) is lower than the water pressure of the expansion water tank (16), and the coolant automatically flows out of the expansion water tank (16) and flows into the electronically controlled water pump (1) for water replenishment. 7. A cooling flow matching control method in the cold start process of the engine intelligent cooling system as claimed in claim 1, characterized in that: During the cold start of the diesel engine, since the temperature of the cylinder liner (7) is slower than that of the cylinder head (6), at the beginning of the warm-up period, before the coolant temperature reaches a preset limit value T _b , the first electronically controlled thermostat The device (2) closes the inlet of the cylinder jacket water jacket (9), and the coolant is completely pumped into the cylinder head water jacket (8). After cooling the cylinder head, it enters the first outlet through the second electric control thermostat (10), that is, directly Entering the water pump 1 to form a small circulation loop, the coolant is continuously heated by the cylinder head in this loop, and when the temperature of the coolant rises to the preset limit value T _b , the first electronically controlled thermostat (2) opens the cylinder jacket water jacket ( 9) Inlet, and configure the flow rate of cylinder head water jacket and body water jacket according to the instructions of the electronic control unit (11). (10), before the temperature of the coolant reaches the preset limit value _Tc , the second electronically controlled thermostat (10) still closes the second outlet, the coolant passes through the water pump (1) to form a small circulation loop, and the coolant flows through the The circuit is heated by the cylinder head and the cylinder liner at the same time, until the temperature of the coolant rises to the preset limit T _c , the second electronically controlled thermostat (10) opens the second outlet, and the coolant dissipates heat through the radiator (12) Enter the water pump (1), and the warm-up process ends.