Water-cooled intercooler system

Abstract

The present invention provides a water-cooled intercooler system that can suppress the decrease in intake air temperature while preventing localized boiling of the coolant flowing through the water-cooled intercooler. [Solution] The water-cooled intercooler system is a water-cooled intercooler system mounted on a vehicle, comprising: an engine having a supercharger; a water-cooled intercooler that cools the intake air supercharged by the supercharger; a pump that supplies coolant to the water-cooled intercooler; and a control device that controls the rotation of the pump, wherein when the control device performs temperature rise control to start the engine from a cold state and raise the exhaust temperature of the engine, it performs pump forward and reverse rotation control, which repeatedly rotates the pump in the forward and reverse directions.

Description

Technical Field

[0004] , ,

[0005] ,

[0001] The present disclosure relates to a water-cooled intercooler system.

Background Art

[0002] Conventionally, a water-cooled intercooler system provided with a water-cooled intercooler for cooling intake air supercharged by a supercharger of an engine has been known (see, for example, Patent Document 1). The water-cooled intercooler system of Patent Document 1 includes an air-cooled intercooler, a water-cooled intercooler provided in a bypass passage that bypasses the air-cooled intercooler, and a bypass valve for opening and closing the bypass passage. The water-cooled intercooler system of Patent Document 1 controls the bypass valve to open the bypass passage when the temperature of the NOx catalyst is less than a predetermined activation start temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the water-cooled intercooler system of Patent Document 1, intake air flows through the water-cooled intercooler when the temperature of the NOx catalyst is less than a predetermined activation start temperature. In such a situation, if the circulation of the cooling water flowing through the water-cooled intercooler stops, there is a risk of local boiling due to the heat of the supercharged intake air. On the other hand, if the cooling water of the water-cooled intercooler is constantly circulated, the intake air will become too cold and the exhaust temperature will drop. As a result, the warm-up period becomes longer.

[0005] An object of the present disclosure is to provide a water-cooled intercooler system that can prevent local boiling of the cooling water flowing through the water-cooled intercooler while suppressing a decrease in intake air temperature. [Means for solving the problem]

[0006] The water-cooled intercooler system according to this disclosure is a water-cooled intercooler system mounted on a vehicle, comprising: an engine having a supercharger; a water-cooled intercooler that cools intake air supercharged by the supercharger; a pump that supplies cooling water to the water-cooled intercooler; and a control device that controls the rotation of the pump, wherein when the control device performs temperature rise control to start the engine from a cold state and raise the exhaust temperature of the engine, it performs pump forward and reverse rotation control, which repeatedly rotates the pump in the forward and reverse directions. [Effects of the Invention]

[0007] This water-cooled intercooler system prevents the coolant temperature from dropping by repeatedly rotating the pump in the forward and reverse directions. This suppresses the drop in intake air temperature while also preventing localized boiling of the coolant. [Brief explanation of the drawing]

[0008] [Figure 1] A system diagram of a water-cooled intercooler system according to one embodiment of the present disclosure. [Figure 2] A system diagram of an engine according to one embodiment of the present disclosure. [Figure 3] A diagram showing a fuel injection configuration according to one embodiment of the present disclosure. [Figure 4] A flowchart illustrating a control procedure performed by a control device according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of this disclosure will be described with reference to the drawings.

[0010] As shown in Figures 1 and 2, the water-cooled intercooler system 1 comprises an engine 2, a supercharger 4, a water-cooled intercooler 6, a pump 8, a fuel injector 10, an exhaust gas purification device 12, a control device 14, and an accelerator pedal 16. The water-cooled intercooler system 1 of this embodiment is mounted on a vehicle C. In this embodiment, the engine 2 is a four-stroke diesel engine that injects fuel directly into the cylinder N and causes autoignition.

[0011] As shown in Figure 2, the fuel injector 10 performs fuel injection to supply fuel to cylinder N. In this embodiment, the fuel injector 10 is connected to a fuel injection pump 18 and a pressure accumulator such as a common rail (not shown). The fuel injector 10 is electrically connected to a control device 14, and the injection amount and injection stage are controlled by the control device 14.

[0012] As shown in Figure 3, in this embodiment, the fuel injector 10 injects a pilot injection PiI, a pre-injection PrI, a main injection MI, an after-injection AI, and a post-injection PI per cycle, with intake, compression, expansion, and exhaust being considered as one cycle.

[0013] The main injection MI is injected from the compression stroke to the expansion stroke. The main injection MI injects the majority of the fuel to be injected per cycle. The pilot injection PiI is injected before the main injection MI. The pilot injection PiI is injected in small amounts and can increase the combustion temperature inside the cylinder N, thereby reducing the ignition delay of the main injection MI. Furthermore, the pilot injection PiI can suppress the rapid pressure increase of the main injection MI and reduce combustion noise. The pre-injection PrI is injected immediately before the main injection MI. The pre-injection PrI is injected in small amounts and can reduce combustion noise and nitrogen oxides. The after-injection AI is injected after the main injection MI. The after-injection AI is mainly used to burn any fuel that was not burned by the main injection MI. The post-injection PI is injected after the after-injection AI. The post-injection PI is performed, for example, to increase the temperature of the exhaust gas purification device 12.

[0014] As shown in Figure 1, the exhaust gas purification device 12 is a device that purifies the exhaust gas discharged from the engine 2. The exhaust gas purification device 12 may include, for example, a diesel particulate filter that captures particulate matter in the exhaust gas, a NOx trap that captures NOx, or a urea selective reduction catalytic system that reduces NOx using urea.

[0015] Engine 2 has an intake manifold 2a. The intake manifold 2a is located downstream of the water-cooled intercooler 6 and distributes supercharged intake air to the cylinders of engine 2. The exhaust purification device 12 is located downstream of the supercharger 4 and purifies the exhaust gas.

[0016] The supercharger 4 is a device that pressurizes the intake air supplied to the engine 2. In this embodiment, the supercharger 4 is a turbocharger that uses the exhaust energy discharged from the engine 2 to supercharge the intake air. However, the supercharger 4 may also be a supercharger that supercharges using, for example, the driving force of the engine 2. The upstream side of the supercharger 4 is connected to an air cleaner 4a that draws in outside air. The downstream side of the supercharger 4 is connected to a water-cooled intercooler 6. An outside temperature sensor 4c that detects the temperature of the outside air (outside temperature OT) is attached to the air cleaner 4a. The outside temperature sensor 4c is connected to a control device 14. The downstream side of the water-cooled intercooler 6 is connected to an intake manifold 2a.

[0017] The water-cooled intercooler 6 is a device that cools the intake air supercharged by the supercharger 4. The water-cooled intercooler 6 includes a heat exchanger 6a and a radiator 6b. The heat exchanger 6a has a passage through which coolant passes and a passage through which intake air passes. The coolant passage is connected to the radiator 6b via an outlet passage 6c. The radiator 6b performs heat exchange between the coolant and the intake air, cooling the coolant. The radiator 6b is connected to the pump 8 via a pump inlet passage 6d. A boost pressure sensor 6g for detecting boost pressure is located on the intake passage upstream of the water-cooled intercooler 6. A water temperature sensor 6f for detecting the temperature of the coolant flowing through the water-cooled intercooler 6 (hereinafter referred to as coolant temperature WT in this specification) is located in the pump inlet passage 6d. The boost pressure sensor 6g and the water temperature sensor 6f are electrically connected to the control device 14.

[0018] Pump 8 circulates cooling water. Pump 8 is connected to the heat exchanger 6a via the pump outlet passage 6e. In this embodiment, pump 8 is an electrically operated pump. Pump 8 is electrically connected to the control device 14. The ratio of forward rotation, stop, and reverse rotation periods of pump 8 is controlled by the control device 14.

[0019] The control device 14 controls the rotation of the pump 8. In this embodiment, the control device 14 obtains the forward rotation period Nt, which is the period when the pump 8 is rotating in the forward direction, the stop period St, which is the period when the pump 8 is stopped, and the reverse rotation period Rt, which is the period when the pump 8 is rotating in the reverse direction, and controls the rotation speed of the pump 8. When the pump 8 is rotating in the forward direction, the cooling water flows from the pump 8 through the heat exchanger 6a into the radiator 6b and returns to the pump 8. When the pump 8 is rotating in the reverse direction, the cooling water flows from the pump 8 through the radiator 6b into the heat exchanger 6a and returns to the pump 8.

[0020] The control device 14 is actually an ECU (Electronic Control Unit) composed of a microcomputer including an arithmetic unit, a memory, an input / output buffer, etc. The control device 14 controls various devices of the water-cooled intercooler system 1 based on maps and programs stored in the memory.

[0021] Next, the control procedure executed by the control device 14 will be described using the flowchart of FIG. 4.

[0022] In step S1, the control device 14 determines whether warming-up control for cold start and warming up the exhaust is necessary. In the present embodiment, when the temperature of the cooling water flowing through the engine 2 is less than 40°C, the control device 14 determines that cold start and exhaust warming are necessary. The warming-up control is a control executed when it is necessary to warm up the exhaust purification device 12. As described above, in the present embodiment, the exhaust is warmed up by post-injection PI or after-injection AI. When the control device 14 determines that cold start and exhaust warming are necessary (step S1 YES), the process proceeds to step S2. When the control device 14 determines that cold start and exhaust warming are not necessary (step S1 NO), it returns.

[0023] In step S2, the control device 14 determines whether the outside air temperature OT is less than or equal to the first predetermined outside air temperature OT1. The first predetermined outside air temperature OT1 is an outside air temperature OT (for example, 35°C) at which it is better to cool the intake air even during exhaust warming control. When the control device 14 determines that the outside air temperature OT is less than or equal to the first predetermined outside air temperature OT1 (step S2 NO), the process proceeds to step S3. When the control device 14 determines that the outside air temperature OT is greater than the first predetermined outside air temperature OT1 (step S2 YES), it returns. When the outside air temperature OT is greater than the first predetermined outside air temperature OT1, since the temperature of the intake air also rises, it is better to always rotate the pump 8 forward and cool the intake air by the water-cooled intercooler 6. For this reason, the control device 14 prohibits the forward and reverse rotation control of the pump described later and executes only the forward rotation of the pump 8, which is normal control.

[0024] In step S3, the control device 14 performs pump forward / reverse rotation control, which involves repeatedly rotating the pump 8 forward, stopping it, and rotating it in the reverse direction. After performing the pump forward / reverse rotation control, the control device 14 proceeds to step S4.

[0025] In step S4, the control device 14 determines whether the coolant temperature WT is less than or equal to the first predetermined water temperature WT1. The first predetermined water temperature WT1 is the water temperature of the engine 2 in its cold-start state, and is, for example, a value between 0°C and 40°C. If the coolant temperature WT is less than or equal to the first predetermined water temperature WT1 (step S4 YES), the control device 14 proceeds to step S5. If the coolant temperature WT is greater than the first predetermined water temperature WT1 (step S4 NO), the control device 14 proceeds to step S6.

[0026] In step S5, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 0.9, 1.2, and 0.9 respectively. In step S6, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 1, 1, and 1 respectively. In this way, the control device 14 changes the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt of the pump 8 according to the cooling water temperature WT. Furthermore, the control device 14 increases the ratio of the stop period St as the cooling water temperature WT decreases. This suppresses the cooling of the intake air and makes it easier to raise the exhaust temperature. After executing step S5 or step S6, the control device 14 proceeds to step S7.

[0027] In step S7, the control device 14 calculates the difference between the cooling water temperature WT and the ambient temperature OT and determines whether the difference is greater than or equal to a predetermined temperature Tx. If the control device 14 determines that the difference between the cooling water temperature WT and the ambient temperature OT is greater than or equal to the predetermined temperature Tx (step S7 YES), it proceeds to step S8. If the control device 14 determines that the difference between the cooling water temperature WT and the ambient temperature OT is less than the predetermined temperature Tx (step S7 NO), it proceeds to step S9.

[0028] In step S8, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 1.0, 1.1, and 0.9, respectively. In this way, the control device 14 ensures that the larger the difference between the temperature of the coolant in the water-cooled intercooler (coolant temperature WT) and the ambient temperature of the vehicle C (ambient temperature OT), the lower the ratio of the stop period St and the higher the ratio of the forward rotation period Nt. When the difference between the ambient temperature of the vehicle C (ambient temperature OT) and the coolant temperature WT is large, the cylinder N may be warm, and the intake air is more likely to be heated in the cylinder N. Therefore, the control device 14 increases the proportion of the forward rotation period Nt to cool the intake air more effectively. After executing step S8, the control device 14 proceeds to step S9.

[0029] In step S9, the control device 14 determines whether the cooling water temperature WT is equal to or greater than the second predetermined water temperature WT2. The second predetermined water temperature WT2 is a value higher than the first predetermined water temperature WT1. For example, the second predetermined water temperature WT2 is a value greater than 40°C. If the control device 14 determines that the cooling water temperature WT is equal to or greater than the second predetermined water temperature WT2 (step S9 YES), it proceeds to step S10. If the control device 14 determines that the cooling water temperature WT is less than the second predetermined water temperature WT2 (step S9 NO), it proceeds to step S11.

[0030] In step S10, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 2.0, 0.5, and 0.5 respectively. Thus, the control device 14 increases the ratio of the forward rotation period Nt as the coolant temperature WT increases. As the coolant temperature WT increases, the intake air temperature also rises. Therefore, the exhaust air temperature tends to rise. As a result, the control device 14 increases the forward rotation period Nt to suppress excessive rise in intake air temperature and boiling of the coolant. After executing step S10, the control device 14 proceeds to step S11.

[0031] In step S11, the control device 14 determines whether the boost pressure P is equal to or greater than a predetermined pressure P1. If the control device 14 determines that the boost pressure P is equal to or greater than the predetermined pressure P1 (step S11 YES), it proceeds to step S12. The predetermined pressure P1 is, for example, a pressure greater than 0.2 atmospheres (a pressure 0.2 atmospheres higher than atmospheric pressure). If the control device 14 determines that the boost pressure P is less than the predetermined pressure P1 (step S11 NO), it proceeds to step S13.

[0032] In step S12, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 2.5, 0.2, and 0.2 respectively. As the boost pressure P increases, the intake air temperature also increases. Therefore, the advantage of suppressing intake air cooling by the water-cooled intercooler through pump forward and reverse rotation control is reduced, while the possibility of the coolant boiling increases. For this reason, the control device 14 increases the forward rotation period Nt to suppress the boiling of the coolant. After executing step S12, the control device 14 proceeds to step S13.

[0033] In step S13, the control device 14 determines whether the heating of the exhaust gas purification device 12 by the heating control has been completed. In this embodiment, the control device 14 detects the temperature of the exhaust gas purification device 12 and determines that the heating has been completed if the temperature is at the temperature at which the catalyst of the exhaust gas purification device 12 is activated. If the control device 14 determines that the heating has been completed (step S13 YES), it terminates the heating control and proceeds to step S14. If the control device 14 determines that the heating has not been completed (step S13 NO), it proceeds to step S3 and continues the pump forward and reverse rotation control.

[0034] In step S14, the control device 14 sets the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt to 3.0:0:0, in that order. That is, the control device 14 returns the pump 8 to normal control and continues forward rotation only. The control device 14 returns after executing step S14.

[0035] As described above, this disclosure provides a water-cooled intercooler system that can suppress a decrease in intake air temperature while preventing the cooling water flowing through the water-cooled intercooler 6 from boiling locally.

[0036] <Other Embodiments> Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. In particular, the various modifications described herein can be combined as needed.

[0037] In the embodiments described above, engine 2 was described using a diesel engine as an example, but this disclosure is not limited to this. Engine 2 may be, for example, a gasoline engine. In addition, engine 2 may be any engine that requires exhaust gas temperature rise.

[0038] In the above embodiments, numerical values ​​were used to illustrate an example of the ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt. However, this disclosure is not limited to the numerical values ​​of the above embodiments. The ratio of the forward rotation period Nt, the stop period St, and the reverse rotation period Rt may be changed as appropriate. [Explanation of Symbols]

[0039] 1: Water-cooled intercooler system, 2: Engine, 2a: Intake manifold 4: Supercharger, 6: Water-cooled intercooler, 8: Pump, 14: Control unit C: Vehicle Nt: Forward rotation period, Rt: Reverse rotation period, St: Stop period OT: Ambient temperature, Tx: Specified temperature WT: Intercooler coolant temperature WT1: 1st predetermined water temperature, WT2: 2nd predetermined water temperature

Claims

1. A water-cooled intercooler system installed in a vehicle, An engine with a supercharger, A water-cooled intercooler that cools the intake air supercharged by the supercharger, A pump that supplies cooling water to the water-cooled intercooler, A control device for controlling the rotation of the pump, Equipped with, When the control device performs temperature rise control to start the engine from a cold state and raise the exhaust temperature of the engine, it performs pump forward and reverse rotation control, which involves repeatedly rotating the pump forward, stopping, and rotating it in the reverse direction. Water-cooled intercooler system.

2. The control device is The forward rotation period is the period during which the pump is rotating in the forward direction, The shutdown period is the period during which the pump is stopped, The reverse rotation period is the period during which the pump rotates in reverse, Obtain, The ratio of the forward rotation period, the stop period, and the reverse rotation period are varied according to the temperature of the cooling water. The water-cooled intercooler system according to claim 1.

3. The ratio of the aforementioned shutdown period is longer the lower the temperature of the cooling water. The water-cooled intercooler system according to claim 2.

4. The greater the difference between the temperature of the cooling water and the ambient temperature of the vehicle, the lower the proportion of the stopping period and the higher the proportion of the forward rotation period. The water-cooled intercooler system according to claim 2.

5. The higher the temperature of the cooling water, the higher the ratio of the forward rotation period. The water-cooled intercooler system according to claim 2.

6. The higher the boost pressure, which is the pressure of the intake air boosted by the supercharger, the lower the ratio of the stop period and the higher the ratio of the forward rotation period. The water-cooled intercooler system according to claim 2.

7. When the temperature rise control is terminated, the pump forward / reverse rotation control is terminated. The water-cooled intercooler system according to claim 1.

8. If the outside temperature of the vehicle is above a predetermined temperature, the forward and reverse rotation control of the pump is prohibited. A water-cooled intercooler system according to any one of claims 1 to 7.

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