An engine test bench water temperature control system

Abstract

The present invention relates to the technical field of engine test equipment, and more specifically, to a water temperature control system for an engine test bench. The water temperature control system includes a PLC and a circulation loop. The circulation loop includes a water pump, a heating device, a heat exchanger, and a liquid replenishing pipe. The water pump, the heating device, the heat exchanger, and the liquid replenishing pipe are connected in series through pipelines. The circulation loop is also provided with an A end and a B end for connecting the water inlet and outlet of the engine. The A end is located on the water outlet side of the liquid replenishing pipe, and the B end is located on the water inlet side of the water pump. The PLC is electrically connected to each component of the circulation loop and centrally controls them. The circulation loop also includes a temperature control proportional valve for adjusting the water temperature in real time, and the temperature control proportional valve is arranged at the engine water inlet and outlet. The water flow sequentially passes through the water pump, the heating device, the heat exchanger, and the liquid replenishing pipe, enters the engine from the A end, then flows out from the B end, and re-enters the water pump, circulating in this way.

Description

Technical Field

[0001] The present invention relates to the technical field of engine test equipment, and more specifically, to a water temperature control system for an engine test bench. Background Art

[0002] The water temperature control system for an engine test bench is mainly used to control the temperature of the coolant to maintain within the target temperature range T1 during the bench test of the engine. The current water temperature control system for an engine test bench mainly has the following problems: 1) The water temperature controller (proportional valve) is commonly installed near the inlet and outlet of the heat exchanger. Since the equipment such as the heat exchanger has a large external dimension, it is generally installed more than 2 meters away from the engine. However, the actual temperature point to be controlled by the equipment is the position of the engine outlet. This installation distance directly leads to a lag in equipment temperature control and large fluctuations in water temperature control; 2) The existing water temperature control system uses an embedded resistance heater to heat the coolant, resulting in large heating energy consumption losses and slow heating speed, which affects the efficiency of rapid engine warm-up. In addition, due to the low service life of the resistance heater and high maintenance costs, when repairing and replacing, it is necessary to remove and drain the cooling liquid, with low efficiency; 3) The existing water temperature control system uses a high-level liquid filling and exhaust tank to exhaust the pipeline. However, due to the complex pipeline and fast flow rate, bubbles often cannot be completely exhausted when passing through the exhaust port, and the gas is mixed in the water channel, causing fluctuations in temperature and resulting in low efficiency of controlling the water temperature, as shown in the appendix Figure 3 as shown. Summary of the Invention

[0003] Aiming at the technical disadvantages of the traditional water temperature control system, starting from the source, the present invention optimizes the equipment layout, adopts an innovative flow channel design scheme, and introduces a new heating scheme, providing a water temperature control system for an engine test bench, comprehensively improving the temperature control efficiency of the water temperature control system from three aspects: control, exhaust, and heating.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A water temperature control system for an engine test bench includes a PLC and a circulation loop. The circulation loop includes a water pump for increasing water pressure to promote water flow circulation; a heating device for heating the water flow; a heat exchanger for cooling the water flow; and a liquid filling pipe for discharging bubbles in the water flow and supplementing the loss of the engine liquid level.

[0006] The water pump, heating device, heat exchanger, and liquid supply pipe are connected in series through pipelines. The circulation loop is also provided with ends A and B for connecting the engine's water inlet and outlet. End A is located on the water outlet side of the liquid supply pipe, and end B is located on the water inlet side of the water pump. The PLC is electrically connected to all components of the circulation loop and centrally controls them. The circulation loop also includes a temperature control proportional valve for adjusting the water temperature in real time, which is installed at the engine's water inlet and outlet.

[0007] The water flow successively passes through the water pump, heating device, heat exchanger, and liquid supply pipe, enters the engine from end A, then flows out from end B, and re-enters the water pump, circulating in this way.

[0008] Among them, the temperature control proportional valve is arranged close to the engine's water inlet and outlet, and the corresponding distance is less than 0.8 meters, maximizing the temperature response speed of water temperature control. The pre-positioned design of the temperature control proportional valve greatly shortens the water temperature response time, adjusts the ratio of the engine's water outlet directly returning to the engine's water inlet as required, and shortens the pipeline between the temperature control proportional valve and the engine's water inlet and outlet. Therefore, the lag time for the engine's water outlet temperature to reach the set target temperature can be reduced, the response speed of the water temperature control system can be improved, and the adjustment of the engine's water outlet temperature to quickly respond to the set temperature of the water temperature control system can be achieved. One or more temperature sensors are also provided in the circulation loop.

[0009] In addition, the PLC is the control system of the water temperature control device, presetting the target water flow temperature, measuring the actual water inlet and outlet temperatures of the engine, comparing the temperature differences between the two by the system, controlling the operation of each component, and adjusting the actual water flow temperature in real time.

[0010] Furthermore, the liquid supply pipe includes a pipe body, a water inlet, and a water outlet. The pipe body is vertically arranged with a hollow top. The water inlet is located in the upper middle part of the pipe body, and the water outlet is located at the bottom of the pipe body. The diameter of the pipe body is larger than the caliber of the water outlet. The liquid supply pipe is vertically arranged and designed with an exhaust method of reverse buoyancy flow direction, enabling the bubbles to fully escape upward. All the cold water in the circulation loop first flows through the liquid supply pipe and flows out from the bottom of the liquid supply pipe. The cold water enters the pipe body from the water inlet and flows out from the water outlet at the bottom of the pipe body, thus entering the engine. When the cold water enters the pipe body, due to the action of buoyancy, the bubbles in the cold water will escape vertically upward. Moreover, the diameter of the pipe body is larger than the caliber of the water outlet, so the flow rate of the cold water in the liquid supply pipe decreases, ensuring sufficient escape time for the bubbles and fully discharging the bubbles, completely eliminating the problem of water temperature control fluctuations caused by bubbles.

[0011] Further, the heating device includes a metal heating pipe and an electromagnetic heater controlled by a PLC. The metal heating pipe is connected to a circulation loop for water flow, and the electromagnetic heater heats the metal heating pipe. An electromagnetic heater based on the principle of electromagnetic induction is used. The 50Hz power frequency power supply passes through the electromagnetic heating control cabinet, is first rectified into a DC voltage by a rectifier, and then converted into a 22KHz high-frequency alternating current by an inverter. A high-frequency coil is wound around the outside of the metal heating pipe. When a high-frequency alternating voltage flows through the wound high-frequency coil, a rapidly changing magnetic field that wraps the heating pipe is generated. Due to the rapidly changing magnetic flux, countless small eddy currents are generated inside the heating pipe, causing the metal heating pipe to heat up rapidly, and the water flowing through the metal heating pipe to heat up rapidly, achieving the effect of quickly heating water.

[0012] Further, the surface layer of the metal heating pipe is also covered with a heat insulation and preservation layer. There is a special heat insulation and preservation layer between the high-frequency coil of the electromagnetic heater and the heated metal heating pipe, so that the high-frequency coil will not be affected by high temperature and has a higher service life.

[0013] Further, the heat exchanger is separately connected to a cold water pipe for supplying cold water. The cold water pipe is provided with a pneumatic ball valve for controlling the cold water volume, and the pneumatic ball valve is controlled by a PLC.

[0014] Further, the liquid supplement pipe is also provided with a liquid level switch for detecting the water volume in the liquid supplement pipe, and the liquid level switch is controlled by a PLC. The liquid level switch simultaneously feeds back a signal to the PLC.

[0015] Further, the circulation loop also includes a flow switch for real-time monitoring of water flow. The flow switch is arranged at the B end position and is controlled by a PLC. The flow switch simultaneously feeds back a signal to the PLC.

[0016] Further, the liquid supplement pipe is also provided with a liquid level indicator for displaying the liquid level in the pipe. The liquid level indicator is a liquid level display pipe or an optoelectronic liquid level gauge. The liquid level indicator is convenient for directly observing the liquid position in the liquid supplement pipe.

[0017] Further, it also includes a fixed cabinet, and the water pump, heating device, heat exchanger, and liquid supplement pipe are all installed in the fixed cabinet. Most components of the water temperature control system are fixed in the fixed cabinet through detachable metal brackets.

[0018] Further, the PLC is also connected to an electric cabinet, which is installed in the fixed cabinet and hinged to the fixed cabinet. The electric cabinet adopts a rotatable hinge fixed design. By using the hinge fixation, the electric cabinet can swing outwards up to 120°, making the most of the space layout on the back of the electric cabinet and having enough space for the maintenance of the wire harness.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The front placement of the temperature control proportional valve significantly improves the response speed of water temperature control. By adjusting the ratio of the engine's outgoing water directly returning to the engine's incoming water as needed, the pipeline between the temperature control proportional valve and the engine's inlet and outlet is shortened, reducing the lag time for the engine's outgoing water temperature to reach the set target temperature and improving the response speed of the water temperature control device; 2) The design of the exhaust method with an anti-buoyancy flow direction enables the bubbles in the cold water to be effectively separated from the cold water in the liquid replenishing pipe, fully exhausting the bubbles in the cold water and eliminating the problem of water temperature control fluctuations caused by bubbles; 3) The use of an electromagnetic heater results in lower energy consumption and higher efficiency of the water temperature control device. The electromagnetic heater can separate water and electricity, reducing the possibility of electric leakage. Compared with the embedded resistance heater, it can reduce energy consumption by 30% and has a longer service life. Moreover, since the high-frequency coil can be replaced without emptying the cold water in the circulation loop, the maintenance cost is lower; 4) Most of the components of the water temperature control device are arranged in a fixed cabinet, with a more reasonable and compact component layout, reducing the occupied space. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the overall structure of the present invention Figure 1 .

[0021] Figure 2 is a schematic diagram of the overall structure of the present invention Figure 2 .

[0022] Figure 3 is a structural diagram of the existing bubble discharge.

[0023] Figure 4 is a connection relationship diagram of each component of the present invention.

[0024] Figure 5 is a structural diagram of the liquid replenishing pipe.

[0025] Figure 6 is a structural diagram of the heating device.

[0026] Figure 7 is the structure of the fixed cabinet Figure 1 .

[0027] Figure 8 is the structure of the fixed cabinet Figure 2 (hinged rotation state).

[0028] Figure 9 is a control flow chart.

[0029] Among them, 1 is the PLC, 2 is the water pump, 3 is the heating device, 4 is the heat exchanger, 5 is the liquid replenishing pipe, 6 is the engine, 7 is the temperature control proportional valve, 8 is the cold water pipe, 9 is the pneumatic ball valve, 10 is the liquid level switch, 11 is the flow switch, 12 is the fixed cabinet, 13 is the electric cabinet, 31 is the metal heating pipe, 51 is the pipe body, 52 is the water inlet, and 53 is the water outlet. Detailed implementation mode

[0030] The accompanying drawings are only for illustrative purposes and should not be construed as limiting the present patent; for better illustration of this embodiment, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and should not be construed as limiting the present patent.

[0031] Embodiment 1

[0032] As Figure 1 、 2 、shown in 4, this embodiment provides a water temperature control system for an engine test bench, including a PLC 1, a circulation loop and a fixed cabinet 12. The circulation loop includes a water pump 2, a heating device 3, a heat exchanger 4, and a liquid supplement pipe 5. The water pump 2, the heating device 3, the heat exchanger 4, and the liquid supplement pipe 5 are connected in series through pipelines. The PLC 1 is electrically connected to each component of the circulation loop and centrally controls them.

[0033] Specifically, the water pump 2 is used to increase the water pressure and promote the flow and circulation of water; the heating device 3 is used to heat the water flow; the heat exchanger 4 is used to supplement cold water and assist in changing the temperature of the water flow; the liquid supplement pipe 5 is used to discharge the air bubbles in the water flow and supplement the liquid level loss of the engine 6, and directly inject liquid into the engine 6.

[0034] The circulation loop is also provided with an A end and a B end for connecting the water inlet and outlet of the engine 6. The A end is located on the water outlet side of the liquid supplement pipe 5, and the B end is located on the water inlet side of the water pump 2.

[0035] In addition, the circulation loop further includes a temperature control proportional valve 7 for adjusting the water temperature in real time. The temperature control proportional valve 7 is arranged at the water inlet and outlet 53 of the engine 6. The temperature control proportional valve 7 is arranged close to the water inlet and outlet 53 of the engine 6, maximizing the temperature response speed of the water temperature control. The front-mounted design of the temperature control proportional valve 7 greatly shortens the water temperature response time, adjusts the proportion of the direct return of the engine 6 outlet water to the engine 6 inlet according to the demand, and shortens the pipeline between the temperature control proportional valve 7 and the water inlet and outlet of the engine 6. Therefore, the lag time for the engine 6 outlet water temperature to reach the set target temperature can be reduced, the response speed of the water temperature control system can be improved, and the adjustment of the engine 6 outlet water temperature to quickly respond to the set temperature of the water temperature control system can be realized.

[0036] The water flow sequentially passes through the water pump 2, the heating device 3, the heat exchanger 4, the liquid supplement pipe 5, enters the engine 6 from the A end, then flows out from the B end, and re-enters the water pump 2 to circulate in this way.

[0037] Specifically, the liquid supplement pipe 5 includes a pipe body 51, a water inlet 52, and a water outlet 53. The pipe body 51 is vertically arranged with a hollow top. The water inlet 52 is located in the upper-middle part of the pipe body 51, and the water outlet 53 is located at the bottom of the pipe body 51. The diameter of the pipe body 51 is larger than the caliber of the water outlet 53. In addition, the liquid supplement pipe 5 is also provided with a liquid level switch 10 for detecting the water volume in the liquid supplement pipe 5 and a liquid level gauge for displaying the liquid level in the pipe. The liquid level switch 10 is controlled by the PLC1, and the liquid level gauge is a liquid level display pipe or an optoelectronic liquid level gauge. An automatic exhaust valve and a manual water replenishment port are also arranged at the top of the liquid supplement pipe 5.

[0038] As Figure 5 shown, the liquid supplement pipe 5 is vertically arranged and designed with an exhaust method of reverse buoyancy flow direction to fully discharge the bubbles. All the cold water in the circulation loop first flows through the liquid supplement pipe 5 and flows out from the bottom of the liquid supplement pipe 5. The cold water enters the pipe body 51 from the water inlet 52 and flows out from the water outlet 53 at the bottom of the pipe body 51, and then enters the engine 6. When the cold water enters the pipe body 51, due to the action of buoyancy, the bubbles in the cold water will escape vertically upward. Moreover, the diameter of the pipe body 51 is larger than the caliber of the water outlet 53, so the flow rate of the cold water in the liquid supplement pipe 5 decreases, ensuring that the bubbles have sufficient escape time to fully discharge the bubbles and completely eliminating the problem of water temperature control fluctuations caused by bubbles.

[0039] Specifically, the heating device 3 includes a metal heating pipe 31 and an electromagnetic heater controlled by the PLC1. The metal heating pipe 31 is connected to the circulation loop for water flow through, and the electromagnetic heater heats the metal heating pipe 31. At the same time, the surface layer of the metal heating pipe 31 is also covered with a heat insulation and heat preservation layer, so that the high-frequency coil will not be affected by high temperature and has a higher service life.

[0040] As Figure 6 shown, an electromagnetic heater based on the principle of electromagnetic induction is used. The 50Hz power frequency power supply passes through the electromagnetic heating control cabinet 32, is first rectified into a DC voltage by a rectifier, and then converted into a 22KHz high-frequency alternating current by an inverter. A high-frequency coil is wound outside the metal heating pipe 31. When the high-frequency alternating voltage flows through the wound high-frequency coil, a rapidly changing magnetic field that wraps the heating pipe is generated. The heating pipe generates countless small eddy currents inside due to the rapid change of the magnetic flux, and the countless small eddy currents cause the metal heating pipe 31 to heat up rapidly, so that the water flowing through the metal heating pipe 31 is quickly heated, achieving the effect of quickly heating the water. Compared with the traditional embedded resistance heater, there is no need to insert a heating resistor into the pipe, and the flow resistance of the coolant is smaller. The electromagnetic heater also has the advantages of energy saving, adjustable constant temperature control, and low maintenance cost.

[0041] Specifically, the heat exchanger 4 is separately connected to a cold water pipe 8 for supplying cold water. The cold water pipe 8 is provided with a pneumatic ball valve 9 for controlling the cold water volume, and the pneumatic ball valve 9 is controlled by the PLC1.

[0042] Specifically, the circulation loop further includes a flow switch 11 for real-time monitoring of water flow. The flow switch 11 is provided at the B end position and is controlled by the PLC1.

[0043] Specifically, the heating device 3 is connected to an electrical cabinet 13. The electrical cabinet 13 is placed in the fixed cabinet 12 and is hinged to the fixed cabinet 12. Among them, the water pump 2, the heating device 3, the heat exchanger 4, the liquid supplement pipe 5, and the electrical cabinet 13 are all placed in the fixed cabinet 12. As Figures 7-8 shown, according to the connection sequence of the components, the heat exchanger 4 and the heating device 3 are arranged in one layer, and the water pump 2 and the liquid supplement pipe 5 are in another layer. At the same time, by arranging both layers of components close to the frame edge. The left end of the heat exchanger 4 is connected to the cooling water and condensate water pipelines, and the right end is connected to the engine 6 water temperature control system; the water pump 2 is connected to the electromagnetic heater; the outlet 53 of the electromagnetic heater is connected to the inlet 52 of the right end of the heat exchanger 4; the lower end of the liquid supplement pipe 5 is connected to the water pipe connected to the inlet 52 of the engine 6. The layout design of component layering and separation minimizes the overall size. According to the connection sequence of the components, the heat exchanger 4 and the heating device 3 are arranged in one layer, and the water pump 2 and the liquid supplement pipe 5 are in another layer. The layered layout structure can not only effectively shorten the pipeline, but also reserve enough space for the installation of the electrical cabinet 13. The electrical cabinet 13 adopts a rotatable hinge fixed design. By using the hinge fixation, the electrical cabinet 13 can swing outwards up to 120°, maximizing the use of the space layout on the back of the electrical cabinet 13 and having enough space for the maintenance of the wire harness.

[0044] The control principle of this water temperature control system is as follows:

[0045] As Figure 4 shown, the water discharged from the engine 6 first passes through the water pump 2, then through the heating device 3, and then enters the heat exchanger 4. The water discharged from the right end of the heat exchanger 4 first passes through the liquid supplement pipe 5, then through the temperature control proportional valve 7 and finally returns to the engine 6. The left end of the heat exchanger 4 is connected to the cooling water and condensate water pipelines, and the pneumatic ball valve 9 controls the inflow and outflow of the cooling water. A bypass valve is arranged between the outlet of the liquid supplement pipe 5 and the inlet pipeline of the water pump 2. The liquid level alarm switch is arranged in the liquid supplement pipe 5, and the flow detection switch is arranged at the outlet 53 of the engine 6.

[0046] The control flow chart of the water temperature control system is as Figure 9 shown. The preset target water flow temperature is T1, and the engine outlet water temperature is T2. When the liquid level alarm switch alarms due to water shortage or the flow detection switch alarms due to flow for more than 3 seconds, the pneumatic ball valve 9, the heating device 3, and the water pump 2 are all closed, the temperature control proportional valve 7 maintains its state, and the PLC1 system shuts down and alarms.

[0047] In the non-alarm state, when the engine 6 stops and the set temperature T1 is higher than the engine 6 outlet water temperature T2, the heating device 3 intervenes to work, the pneumatic ball valve 9 is closed, and cold water no longer enters the circulation loop. The heating device 3 quickly heats the water flow to raise the water temperature.

[0048] In the non-alarm state, when the engine 6 continues to be tested, the water pump 2 is turned on, the temperature control proportional valve 7 adjusts the water flow as required, the pneumatic ball valve 9 is opened to release cold water for heat exchange, the heating device 3 is not started, and the PLC 1 system controls the normal operation of the circulation loop.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. An engine test bench water temperature control system, characterized in that: It includes a PLC (1) and a circulation loop, and the circulation loop includes a water pump (2) for increasing water pressure to promote the circulation of water flow; a heating device (3) for heating the water flow; a heat exchanger (4) for cooling the water flow; a liquid replenishing pipe (5) for discharging air bubbles in the water flow and supplementing the liquid level loss of the engine (6); the water pump (2), the heating device (3), the heat exchanger (4), and the liquid replenishing pipe (5) are connected in series through pipelines. The circulation loop also has an A end and a B end for connecting the water inlet and outlet of the engine (6). The A end is located on the water outlet side of the liquid replenishing pipe (5), and the B end is located on the water inlet side of the water pump (2). The PLC (1) is electrically connected to each component of the circulation loop and centrally controls them. The circulation loop also includes a temperature control proportional valve (7) for adjusting the water temperature in real time, and the temperature control proportional valve (7) is arranged at the water inlet and outlet (53) of the engine (6); The water flow successively passes through the water pump (2), the heating device (3), the heat exchanger (4), the liquid replenishing pipe (5), enters the engine (6) from the A end, then flows out from the B end, and re-enters the water pump (2) to circulate in this way; The liquid replenishing pipe (5) includes a pipe body (51), a water inlet (52), and a water outlet (53). The pipe body (51) is vertically arranged with a hollow top. The water inlet (52) is located in the upper middle part of the pipe body (51), and the water outlet (53) is located at the bottom of the pipe body (51). The diameter of the pipe body (51) is larger than the diameter of the water outlet (53). The circulation loop also includes a flow switch (11) for real-time monitoring of the water flow rate, and the flow switch (11) is arranged at the B end and is controlled by the PLC (1).

2. The water temperature control system of an engine test bench according to claim 1, characterized in that: The heating device (3) includes a metal heating pipe (31) and an electromagnetic heater controlled by the PLC (1). The metal heating pipe (31) is connected to the circulation loop for the water flow to pass through, and the electromagnetic heater heats the metal heating pipe (31).

3. The water temperature control system of an engine test bench according to claim 2, characterized in that: The surface layer of the metal heating pipe (31) is also covered with a heat insulation and heat preservation layer.

4. The water temperature control system for an engine test bench according to claim 1, wherein: The heat exchanger (4) is separately connected to a cold water pipe (8) for providing cold water. The cold water pipe (8) is provided with a pneumatic ball valve (9) for controlling the amount of cold water, and the pneumatic ball valve (9) is controlled by the PLC (1).

5. The water temperature control system of an engine test bench according to claim 1, characterized in that: The liquid replenishing pipe (5) is also provided with a liquid level switch (10) for detecting the water volume in the liquid replenishing pipe (5), and the liquid level switch (10) is controlled by the PLC (1).

6. The water temperature control system of an engine test bench according to claim 1, wherein: The liquid replenishing pipe (5) is also provided with a liquid level gauge for displaying the liquid level in the pipe, and the liquid level gauge is a liquid level display pipe or an optoelectronic liquid level gauge.

7. The water temperature control system of an engine test bench according to claim 1, characterized in that: It also includes a fixed cabinet (12), and the water pump (2), the heating device (3), the heat exchanger (4), and the liquid replenishing pipe (5) are all arranged in the fixed cabinet (12).

8. The water temperature control system of an engine test bench according to claim 7, characterized in that: The PLC (1) is also connected to an electric cabinet (13), and the electric cabinet (13) is arranged in the fixed cabinet (12) and is hinged to the fixed cabinet (12).

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