JP7420044B2 - Internal combustion engine cooling system - Google Patents

Description

The present invention relates to a cooling system installed in an internal combustion engine.

An internal combustion engine consists of many parts, and it is desired to further save space and reduce the number of parts. Therefore, techniques have been disclosed that can further save space and reduce the number of parts in an internal combustion engine. For example, Patent Document 1 discloses the following cooling device for an internal combustion engine. The internal combustion engine described in Patent Document 1 is a compression ignition type internal combustion engine (diesel engine), and includes a supercharger (so-called turbocharger) that supercharges using the energy of exhaust gas, and an intake air passage provided in the intake path. The engine includes an intercooler that cools the engine, a fuel addition valve provided in the exhaust path, and a urea water addition valve provided in the exhaust path.

Here, the fuel addition valve supplies fuel to the exhaust pipe in order to burn and incinerate particulate matter (PM) accumulated in a particulate matter removal filter (DPF) installed in the exhaust route. Inject into exhaust gas. Combustion and incineration means that the injected fuel burns in the exhaust gas, the temperature of the exhaust gas rises, and the particulate matter deposited in the particulate matter removal filter burns. Furthermore, the urea water addition valve injects urea water into the exhaust pipe in order to purify nitrogen oxides (NOx) using a selective catalytic reduction (SCR) catalyst provided in the exhaust path.

The cooling device described in Patent Document 1 uses cooling water to cool three of the intercooler, the fuel addition valve, and the urea water addition valve. The cooling system consists of a radiator dedicated to the cooling system that is separate from the radiator that cools the cooling water of the internal combustion engine, an electric water pump that pumps the cooling water cooled by the radiator dedicated to the cooling system, and a cooling system. It is equipped with a circuit. The cooling circuit consists of a cooling water pressure feeding passage in which a radiator and an electric water pump are installed, an intercooler cooling passage in which an intercooler is installed, and an addition valve cooling passage in which a fuel addition valve and a urea water addition valve are installed in series. The passages and are connected in parallel. In the cooling circuit, when the cooling water cooled by the radiator is pumped by the electric water pump, the cooling water is passed through the intercooler cooling passage where the intercooler is installed, and the addition valve cooling where the fuel addition valve and urea water addition valve are installed. It flows into the passageway. As a result, the cooling water cooled by the intercooler is pumped to all of the intercooler, fuel addition valve, and urea water addition valve.

Here, instead of providing dedicated electric water pumps for each of the three, the fuel addition valve, urea water addition valve, and intercooler, one electric water pump is used for both, and two electric water pumps are used. The pump has been omitted. As a result, the cooling device for an internal combustion engine described in Patent Document 1 can further save space and reduce the number of parts, and in turn, it is possible to further save space and reduce the number of parts for the internal combustion engine. can.

JP 2018-3669 Publication

By the way, as mentioned above, when the fuel addition valve is used for combustion and incineration, the fuel injected from the fuel addition valve burns in the exhaust gas and the temperature of the exhaust gas rises to a high temperature. The gas heats the fuel addition valve. Then, when the intake air is sufficiently cool and there is no need to pump cooling water to the intercooler that cools the intake air, combustion incineration may be performed and the fuel addition valve may need to be cooled. In this case, even though there is no need to forcefully feed cooling water to the intercooler, there is a need to forcefully feed cooling water to the fuel addition valve in order to cool the fuel addition valve, as described in Patent Document 1. When the cooling system uses an electric water pump to pump cooling water to cool the fuel addition valve, the cooling water is pumped not only to the fuel addition valve but also to the intercooler, causing the intercooler to excessively cool the intake air. There is a risk.

The present invention has been devised in view of the above points, and it is possible to further save space and reduce the number of parts, and also to reduce the need for pumping coolant to the intercooler. An object of the present invention is to provide a cooling system that can cool an addition valve while suppressing excessive cooling of intake air by a cooler.

In order to solve the above problems, a first invention provides an intercooler provided in an intake path of an internal combustion engine having a supercharger that supercharges intake air, and an internal combustion engine that cools an internal combustion engine coolant flowing inside the internal combustion engine. An internal combustion engine comprising: an intercooler radiator that is separate from an engine radiator and cools coolant flowing in the intercooler; an electric pump that circulates the coolant; and a control device that controls the electric pump. In the cooling system, the exhaust path of the internal combustion engine is provided with an additive valve that injects an additive into the exhaust gas in order to purify the exhaust gas, and the electric pump is connected to the intercooler radiator. and the intercooler and the addition valve, the controller is capable of circulating the coolant and stopping circulation of the coolant between the intercooler and the addition valve; an addition valve temperature detection unit that estimates or measures a valve-related temperature; an addition valve cooling request determination unit that determines whether cooling of the addition valve is necessary based on the addition valve-related temperature; and a control unit that controls the electric pump. an electric pump control section, and when the addition valve cooling request determination section determines that there is a need to cool the addition valve, the electric pump control section supplies a specified amount of the coolant to the electric pump. This is a cooling system for internal combustion engines.

Next, a second invention is the cooling system for an internal combustion engine according to the first invention, wherein the control device determines that the addition valve-related temperature is a predetermined temperature in the addition valve cooling request determination section. This cooling system for an internal combustion engine determines that the addition valve needs to be cooled when the temperature exceeds a certain cooling start temperature.

Next, a third invention is the cooling system for an internal combustion engine according to the first invention or the second invention, wherein the addition valve is housed in an addition valve holder, and the addition valve is housed in an addition valve holder. is filled with the circulated coolant, and the control device measures the temperature of the coolant in the vicinity of the coolant outlet, which is the outlet of the coolant in the addition valve holder, using the addition valve temperature detection section. , the cooling system of the internal combustion engine, estimating or measuring the addition valve related temperature.

Next, a fourth invention is the cooling system for an internal combustion engine according to the third invention, wherein the control device determines, in the addition valve cooling request determination section, that there is a need to cool the addition valve. If the determination is made, the electric pump control unit causes the electric pump to force-feed the prescribed amount of the coolant that can replace the entire amount of the coolant in the addition valve holder.

Next, a fifth invention is the cooling system for an internal combustion engine according to the third invention or the fourth invention, wherein the control device cools the addition valve in the addition valve cooling request determination section. If it is determined that there is a need for It is a cooling system for internal combustion engines that controls the

Next, a sixth invention is the cooling system for an internal combustion engine according to the fifth invention, wherein the control device is an inlet for the coolant in the addition valve holder in the electric pump control section. The cooling system for an internal combustion engine corrects the drive time based on the kinematic viscosity of the coolant near a coolant inlet.

Next, a seventh invention is the cooling system for an internal combustion engine according to the sixth invention, wherein the control device controls an inflow coolant whose temperature is the temperature of the coolant near the coolant inlet in the addition valve holder. It has an inflow coolant temperature detection unit that estimates or measures temperature, and the control device has the drive time set in accordance with the inflow coolant temperature related to the kinematic viscosity of the coolant flowing in from the coolant inlet. Inflow coolant temperature/driving time characteristics are stored in association with the discharge flow rate, and the control device determines that there is a need to cool the addition valve in the addition valve cooling request determination section, The electric pump control unit determines the discharge flow rate, determines the driving time based on the determined discharge flow rate, the inflow coolant temperature, and the inflow coolant temperature/driving time characteristic, and calculates the determined discharge flow rate. and a cooling system for an internal combustion engine that controls the electric pump based on the driving time.

Next, an eighth invention is the cooling system for an internal combustion engine according to any one of the fifth to seventh inventions, wherein the control device, based on the operating state of the internal combustion engine, The intercooler cooling request determination section determines whether cooling of the intercooler is necessary, and the addition valve cooling request determination section and the intercooler cooling request determination section determine whether cooling of the addition valve is necessary and the intercooler cooling requirement determination section. If it is determined that there is no need to cool the cooler, the electric pump control section stops the operation of the electric pump, and if there is no need to cool the addition valve and there is no need to cool the intercooler. If it is determined that it is necessary, the electric pump control unit determines the discharge flow rate and drive time of the electric pump with respect to the intercooler, and controls the electric pump based on the determined discharge flow rate and drive time. If it is determined that there is a need to cool the addition valve and there is no need to cool the intercooler, the electric pump control section controls the discharge flow rate and drive time of the electric pump for the addition valve. is determined, and the electric pump is controlled based on the determined discharge flow rate and the drive time, and if it is determined that there is a need to cool both the addition valve and the intercooler, The electric pump control unit determines the discharge flow rate and drive time of the electric pump to the addition valve, and the discharge flow rate and drive time of the electric pump to the intercooler, and calculates the discharge flow rate and drive time of the electric pump to the intercooler. The cooling system for an internal combustion engine controls the electric pump based on the discharge flow rate and the drive time on the side where the amount of the coolant increases.

According to the first invention, when the electric pump pumps the coolant, the coolant cooled by the intercooler radiator is pumped to both the intercooler and the addition valve, and one electric pump pumps the coolant to the intercooler and the addition valve. to be pumped. In this way, in the cooling system, one electric pump serves as both an electric pump for the intercooler and an electric pump for the addition valve, both of which are used to pump the coolant. Thereby, it is possible to further save space and reduce the number of parts of the cooling system, and in turn, it is possible to further save space and reduce the number of parts of the internal combustion engine.

The control device forces the electric pump to pump coolant to cool the addition valve when the addition valve cooling request determination unit determines that the addition valve needs to be cooled based on the temperature related to the addition valve. to be done. Therefore, even if there is no need to cool the intake air with the intercooler, coolant is forced to be pumped from the electric pump only when the addition valve cooling request determination section determines that cooling the addition valve is necessary. Often, it is not always necessary to force coolant through an electric pump. Thereby, when there is no need to force-feed coolant to the intercooler, excessive cooling of intake air by the intercooler can be suppressed. Therefore, the cooling system can further save space and reduce the number of parts, and also prevents the intercooler from excessively cooling the intake air when there is no need to pump coolant to the intercooler. At the same time, the addition valve can be cooled.

According to the second invention, the control device only determines whether the addition valve-related temperature exceeds the cooling start temperature which is a predetermined temperature in the addition valve cooling request determination section, and It is possible to determine whether cooling is necessary. Therefore, the control device can easily determine whether or not cooling of the addition valve is necessary.

According to the third invention, since the coolant is heated by the heat of the addition valve in the addition valve holder that accommodates the addition valve, the temperature of the coolant near the coolant outlet of the addition valve holder is estimated or measured. The addition valve-related temperature, which is , tends to change depending on the temperature of the addition valve. Then, the control device determines whether cooling of the addition valve is necessary or not based on the addition valve-related temperature, which tends to change depending on the temperature of the addition valve. Therefore, the control device can more accurately determine whether cooling of the addition valve is necessary.

According to the fourth invention, when the control device determines that there is a need to cool the addition valve, the electric pump control unit supplies a specified amount of coolant that allows the entire amount of coolant in the addition valve holder to be replaced. It is pumped by an electric pump. As a result, the entire amount of coolant in the addition valve holder is replaced, so that the coolant in the addition valve holder is cooled more reliably. In turn, the cooling system can ensure that the addition valve is cooled when it needs to be cooled.

According to the fifth invention, when the control device determines that there is a need to cool the addition valve, the electric pump control section determines the discharge flow rate and drive time of the electric pump corresponding to the specified amount; The electric pump is controlled based on the discharge flow rate and driving time. Further, the flow rate of the coolant pumped from the electric pump to the intercooler is determined by the discharge flow rate of the electric pump. As the discharge flow rate of the electric pump increases, the flow rate of the coolant pumped from the electric pump to the intercooler also increases. Here, the control device can appropriately set the discharge flow rate of the electric pump. This allows the control device to control the discharge flow rate of the electric pump for cooling the addition valve when there is no need to forcefully feed coolant to the intercooler and when it is determined that there is a need to cool the addition valve. , it becomes easy to adjust the amount of intake air to a level that does not excessively cool the intake air using the intercooler. By being able to adjust the discharge flow rate in this way, the cooling system can use the intercooler to overflow the intake air when there is no need to pump coolant to the intercooler, and when it determines that there is a need to cool the addition valve. It becomes easy to cool the addition valve while suppressing the cooling.

According to the sixth invention, the control device corrects the driving time based on the kinematic viscosity of the coolant in the vicinity of the coolant inlet, which is the coolant inlet in the addition valve holder, in the electric pump control section. Here, the higher the kinematic viscosity of the coolant, the more difficult the coolant is to flow. Since the kinematic viscosity of the coolant near the coolant inlet of the addition valve holder is the kinematic viscosity of the coolant flowing into the addition valve holder, the higher the kinematic viscosity, the more difficult it becomes for the coolant to flow into the addition valve holder. By correcting the driving time based on the kinematic viscosity of the coolant near the coolant inlet of the addition valve holder, the control device can more accurately force feed the amount of coolant necessary for cooling the addition valve to the addition valve holder. Therefore, the cooling system can cool the addition valve more reliably.

According to the seventh invention, the inflow coolant temperature/driving time characteristics are stored in the control device in association with the discharge flow rate. The control device can read out the inflow coolant temperature/driving time characteristics and easily determine the driving time from the read inflow coolant temperature/driving time characteristics. In addition, the inflow coolant temperature and driving time characteristics are such that the driving time for the addition valve is set according to the inflow coolant temperature related to the kinematic viscosity of the coolant, and the driving time for the addition valve is determined from the inflow coolant temperature and driving time characteristics. Times have been corrected based on kinematic viscosity. Therefore, when the control device determines that there is a need to cool the addition valve, it can easily and quickly calculate the drive time for the addition valve corrected based on the kinematic viscosity.

According to the eighth invention, the control device includes a discharge flow rate of the electric pump to the intercooler necessary for cooling the intercooler, a discharge flow rate of the electric pump to the addition valve necessary for cooling the addition valve, Since the electric pump is controlled based on the side with a larger discharge flow rate, the intercooler and addition valve can be reliably cooled. In addition, when there is no need to cool the intercooler, the electric pump pumps (discharges) coolant when it is determined that the addition valve needs to be cooled. If it is determined that there is no such thing, it is not performed. In this way, when there is no need to cool the intercooler, coolant is forced to be fed (discharged) from the electric pump only when it is necessary to cool the addition valve. Thereby, when there is no need to force-feed coolant to the intercooler, excessive cooling of intake air by the intercooler can be reliably suppressed.

1 is a diagram illustrating a schematic configuration of an internal combustion engine system according to an embodiment. FIG. 3 is a schematic diagram illustrating cooling of the fuel addition valve by the fuel addition valve holder. 3 is a flowchart illustrating processing executed by the control device according to the present embodiment. It is a figure explaining inflow coolant temperature and driving time characteristics. It is a figure explaining cooling of an intercooler and a fuel addition valve in the case where there is no need to force-feed coolant to an intercooler. FIG. 3 is a diagram illustrating the configuration of an internal combustion engine system including a cooling system according to another embodiment. FIG. 3 is a diagram illustrating the configuration of an internal combustion engine system including a cooling system according to another embodiment.

● [Configuration of internal combustion engine system 1 (Figures 1 and 2)]
Hereinafter, a cooling system 70 for an internal combustion engine 10 according to an embodiment of the present invention will be described with reference to the drawings. Internal combustion engine 10 is a diesel engine. Hereinafter, the configuration of the internal combustion engine system 1 including the cooling system 70 will be described in order from the intake side to the exhaust side using FIG. 1.

The intake pipe 11A is provided with an intake flow rate detection device 21, and is connected to the compressor 22B of the supercharger 22. The intake flow rate detection device 21 outputs a detection signal corresponding to the flow rate of air taken into the internal combustion engine 10 to the control device 50. The intake air flow rate detection device 21 is also provided with an intake air temperature detection device 21A (for example, an intake air temperature sensor). The intake air temperature detection device 21A outputs a detection signal according to the temperature of the intake air passing through the intake air flow rate detection device 21 to the control device 50.

A compressor 22B of the supercharger 22 is connected to intake pipes 11A and 11B. The compressor 22B is rotationally driven by a turbine 22A that is rotationally driven by exhaust gas, and pressure-feeds intake air that has flowed in from the intake pipe 11A to the intake pipe 11B (compresses and discharges the intake air).

The intake pipe 11B is connected to the compressor 22B and the intake manifold 11C, and guides intake air compressed from the compressor 22B to the intake manifold 11C. The intake air guided to the intake manifold 11C is sucked into each cylinder of the internal combustion engine 10 and used for combustion together with the fuel injected from the injectors 14A to 14D.

The intake pipe 11B is provided with an intercooler 71 that cools intake air, and an intake air temperature detection device 23 (for example, an intake air temperature sensor) downstream of the intercooler 71. The intake air temperature detection device 23 outputs a detection signal corresponding to the temperature of the intake air whose temperature has been lowered by the intercooler 71 to the control device 50. Although details will be described later, the intercooler 71 is part of the cooling system 70 and cools intake air. Coolant flows inside the intercooler 71 and cools intake air that comes into contact with the intercooler 71.

Although details will be described later, the cooling system 70 includes an intercooler 71, an intercooler radiator 72, an electric pump 73, a fuel addition valve holder 74 that holds the fuel addition valve 61, a coolant circulation passage 75 connecting these, and a control device 50. have. Control device 50 is also part of cooling system 70 and controls electric pump 73. The intercooler radiator 72 is separate from the internal combustion engine radiator 15 that cools the internal combustion engine coolant (not shown) flowing inside the internal combustion engine 10, and cools the coolant flowing inside the intercooler 71.

The accelerator depression amount detection device 25 is, for example, an accelerator depression amount sensor, and outputs a detection signal to the control device 50 according to the amount of depression of the accelerator pedal operated by the driver.

The internal combustion engine 10 is provided with a rotation detection device 27 and a cylinder detection device 28. The rotation detection device 27 is, for example, a rotation sensor, and outputs a detection signal according to the rotation angle of the crankshaft of the internal combustion engine 10 to the control device 50. Further, the cylinder detection device 28 outputs a detection signal to the control device 50, for example, when the piston of the first cylinder reaches the compression top dead center.

The control device 50 calculates the required load based on the rotational speed of the internal combustion engine based on the detection signal from the rotation detection device 27 and the amount of depression of the accelerator pedal based on the detection signal from the accelerator depression amount detection device 25, The amount of fuel is calculated in accordance with the required load, the intake air temperature, etc. based on the detection signal from the intake air temperature detection device 23. The control device 50 controls the injectors 14A to 14D at predetermined timing based on the detection signals from the rotation detection device 27 and the cylinder detection device 28, and controls the injectors 14A to 14D based on the required load and the detection signal from the intake air temperature detection device 23. The amount of fuel is injected according to the temperature of the intake air.

Exhaust gas from the internal combustion engine 10 is guided to the exhaust manifold 12A, the exhaust pipe 12B, and the turbine 22A of the supercharger 22, rotates the turbine 22A, and is discharged to the exhaust pipe 12C. The exhaust gas discharged to the exhaust pipe 12C flows to the exhaust pipe 12D and the exhaust pipe 12E, and then is exhausted to the outside of the vehicle (not shown).

Exhaust from the internal combustion engine 10, which is a diesel engine, contains carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxides (NOx). In order to purify these, the internal combustion engine system 1 includes, from the upstream side, a fuel addition valve 61, a first oxidation catalyst (DOC) 41, and a particulate matter filter (DPF) 42. , a urea water addition valve 62, a selective catalytic reduction (SCR) 43, a second oxidation catalyst 44, and the like. Here, the fuel addition valve 61 and the urea water addition valve 62 are addition valves that are provided in the exhaust path of the internal combustion engine 10 and inject an additive into the exhaust gas in order to purify the exhaust gas.

The exhaust pipe 12C is provided with a fuel addition valve 61, a first oxidation catalyst 41, a DPF 42, a differential pressure sensor 35, exhaust temperature detection devices 36A to 36C, and the like. The first oxidation catalyst 41 oxidizes and purifies carbon monoxide (CO), hydrocarbons (HC), etc. contained in the exhaust gas. The particulate matter collection filter (hereinafter referred to as "DPF") 42 collects particulate matter (PM) contained in the exhaust gas, and allows only the exhaust gas to flow downstream.

The exhaust pipe 12C is provided with a fuel addition valve 61 (addition valve), an exhaust temperature detection device 36A (for example, an exhaust temperature sensor), and the like on the upstream side of the first oxidation catalyst 41. The fuel addition valve 61 is supplied with fuel from a fuel tank (not shown), and injects fuel (additive) into the exhaust gas to regenerate the DPF 42. As described above, when the DPF 42 collects particulate matter contained in the exhaust gas, the collected particulate matter is deposited on the DPF 42 . The DPF 42 is regenerated so that the DPF 42 does not become clogged with accumulated particulate matter. To regenerate the DPF 42, fuel (additive) is injected into the exhaust gas from the fuel addition valve 61, and as the injected fuel burns, the exhaust gas becomes high temperature, and the particulate matter deposited on the DPF 42 is combusted by the high temperature exhaust gas. be incinerated.

Since the fuel addition valve 61 is provided in the exhaust pipe 12C through which high-temperature exhaust gas flows, it is heated by the exhaust gas flowing through the exhaust pipe 12C and the exhaust pipe 12C. As schematically shown in FIG. 2, the fuel addition valve 61 is held in a fuel addition valve holder 74 filled with coolant, and the fuel addition valve 61 is cooled by the fuel addition valve holder 74. As will be described in detail later, the fuel addition valve holder 74 is part of the cooling system 70. The fuel addition valve holder 74 is filled with coolant and is connected to a coolant circulation passage 75 through which the coolant flows, so that the coolant in the fuel addition valve holder 74 can be replaced.

Further, an exhaust gas temperature detection device 36B (for example, an exhaust gas temperature sensor) is provided downstream of the first oxidation catalyst 41 and upstream of the DPF 42. An exhaust gas temperature detection device 36C (for example, an exhaust gas temperature sensor) is provided downstream of the DPF 42. Further, a differential pressure sensor 35 is provided that detects the differential pressure (pressure difference) between the exhaust pressure downstream of the first oxidation catalyst 41 and upstream of the DPF 42 and the exhaust pressure downstream of the DPF 42. .

The control device 50 detects the pressure difference between the upstream side and the downstream side of the DPF 42 based on the detection signal from the differential pressure sensor 35, and controls the accumulation of particulate matter collected in the DPF 42 according to the detected pressure difference. amount can be estimated. When the estimated accumulation amount exceeds a predetermined threshold value, the control device 50 injects fuel from the fuel addition valve 61 to increase the exhaust temperature to burn and incinerate the particulate matter accumulated in the DPF 42. to regenerate the DPF 42. At this time, the control device 50 detects the temperature of the exhaust gas at each position based on the detection signals from the exhaust gas temperature detection devices 36A, 36B, and 36C, and controls the fuel addition valve 61 to add fuel to the exhaust gas in order to maintain the desired temperature. Inject.

The exhaust pipe 12D is provided with, from the upstream side, a NOx detection device 37A, a urea water addition valve 62, a selective catalytic reduction (SCR) 43, an exhaust temperature detection device 36D, a NOx detection device 37B, and the like.

The urea water addition valve 62 is arranged in the exhaust pipe 12D downstream of the DPF 42 and upstream of the selective reduction catalyst (hereinafter referred to as "SCR") 43, and adds urea to the exhaust gas at a predetermined timing. Spray water (additive). The injected urea water (additive) diffuses within the exhaust pipe 12D and reaches the SCR 43. Note that urea water is supplied to the urea water addition valve 62 from a urea water tank (not shown). The SCR 43 uses ammonia gas generated from the injected urea water to reduce and purify nitrogen oxides (NOx) contained in the exhaust gas.

Further, the exhaust pipe 12D on the upstream side of the SCR 43 is provided with a NOx detection device 37A (for example, a NOx sensor). Further, the exhaust pipe 12E on the downstream side of the SCR 43 is provided with a NOx detection device 37B (for example, a NOx sensor) and an exhaust temperature detection device 36D (for example, an exhaust temperature sensor). The NOx detection devices 37A and 37B output detection signals to the control device 50 according to the concentration of NOx in the exhaust gas, and the exhaust temperature detection device 36D outputs to the control device 50 a detection signal according to the temperature of the exhaust gas. The control device 50 calculates the NOx purification rate of the SCR 43 based on the detection signals from the NOx detection devices 37A, 37B and the exhaust temperature detection device 36D, and controls the urea water addition valve 62 based on the calculated NOx purification rate. .

The second oxidation catalyst 44 is connected to the downstream side of the SCR 43 via the exhaust pipe 12E. The second oxidation catalyst 44 oxidizes and purifies ammonia gas remaining in the exhaust gas.

The control device 50 is a known device including a CPU, RAM, ROM, timer, EEPROM, and the like. The CPU executes various calculation processes based on various programs and maps stored in the ROM. Further, the RAM temporarily stores calculation results by the CPU, data input from each detection device, etc., and the EEPROM stores, for example, data to be saved when the internal combustion engine 10 is stopped. Although details will be described later, the EEPROM of the control device 50 stores an inflow coolant temperature and a driving time corresponding to the inflow coolant temperature related to the kinematic viscosity of the coolant flowing into the fuel addition valve holder 74 from the coolant inlet 74A. The driving time characteristic (see FIG. 4) is stored for each discharge flow rate for cooling the fuel addition valve 61 (discharge flow rate for the fuel addition valve 61).

Based on the detection signal input as described above, the control device 50 determines the rotation speed of the internal combustion engine 10, the amount of depression of the accelerator pedal, and the intake air temperature based on the detection signal from the intake air temperature detection device 23. The operating state of the internal combustion engine 10 can be detected. Further, the control device 50 controls the cylinders of the internal combustion engine 10 from each injector 14A to 14D in response to the detected operating state of the internal combustion engine 10 and a request from the driver based on a detection signal from the accelerator depression amount detection device 25. It outputs control signals that control the amount of fuel injected into the fuel tank, the amount of fuel (additive) added (injected) from the fuel addition valve 61, and the amount of urea water added (injected) from the urea water addition valve 62.

Further, as will be described in detail below, the control device 50 is also a part of the cooling system 70, and in order to cool the intercooler 71 and the fuel addition valve 61 (addition valve), the control device 50 includes an addition valve temperature detection section 50A, It has an addition valve cooling request determination section 50B, an electric pump control section 50C, an inflow coolant temperature detection section 50D, and an intercooler cooling requirement determination section 50E. Note that the urea water addition valve 62 is also a type of addition valve, and can also be cooled using an addition valve holder filled with coolant similar to the fuel addition valve holder 74 that holds the fuel addition valve 61. In this embodiment, the urea water addition valve 62 has a dedicated cooling device (not shown).

● [Configuration of cooling system 70 (Figures 1 and 2)]
As shown in FIG. 1, the cooling system 70 includes an intercooler 71, an intercooler radiator 72, an electric pump 73, a fuel addition valve holder 74, an inflow coolant temperature detection device 741, and an outflow coolant temperature detection device 742. and a coolant circulation passage 75. As explained below, the coolant circulation passage 75 connects the intercooler 71, the intercooler radiator 72, the electric pump 73, and the fuel addition valve holder 74, and the coolant flows inside the coolant circulation passage 75. cycle.

As described above, the intercooler 71 is provided in the intake pipe 11B (intake path) that has the supercharger 22 that supercharges intake air to the internal combustion engine 10, and coolant flows inside and touches the intercooler 71. Cools the intake air. The intercooler radiator 72 cools the coolant flowing inside the intercooler 71, and is separate from the internal combustion engine radiator 15, which cools the internal combustion engine coolant (not shown) flowing inside the internal combustion engine 10.

The electric pump 73 is provided in the coolant circulation passage 75, and is controlled by the electric pump control section 50C of the control device 50 to pump the coolant, as will be described later. The electric pump 73 can circulate coolant between the intercooler radiator 72, the intercooler 71, and the fuel addition valve 61 (addition valve), and can stop the circulation of the coolant.

The fuel addition valve holder 74 accommodates the fuel addition valve 61, as schematically shown in FIG. Further, the fuel addition valve holder 74 is filled with circulated coolant. That is, as shown in FIGS. 1 and 2, a portion of the coolant circulating through the coolant circulation passage 75 is filled inside the fuel addition valve holder 74. As shown in FIG. 1, the fuel addition valve holder 74 has a coolant inlet 74A (see FIG. 2) into which coolant flows from the FH distribution pipe 75BC of the coolant circulation passage 75, and a FH return pipe 75CB of the coolant circulation passage 75. A coolant outlet 74B (see FIG. 2) through which the coolant flows out is provided.

Further, an inflow coolant temperature detection device 741 (for example, a coolant temperature sensor) is provided in the FH distribution pipe 75BC of the coolant circulation passage 75 located upstream of the coolant inlet 74A. Further, an outflow coolant temperature detection device 742 (for example, a coolant temperature sensor) is provided in the FH return pipe 75CB of the coolant circulation passage 75 located downstream of the coolant outflow port 74B. The inflow coolant temperature detection device 741 and the outflow coolant temperature detection device 742 output a detection signal according to the temperature of the coolant to the control device 50. The control device 50 uses an inflow coolant temperature detection section 50D (to be described later) to detect the inflow coolant, which is the temperature of the coolant near the coolant inlet 74A in the fuel addition valve holder 74, based on a detection signal from the inflow coolant temperature detection device 741. (estimate or) measure temperature. In addition, the control device 50 uses an addition valve temperature detection unit 50A (to be described later) to detect a temperature near a coolant outlet 74B, which is a coolant outlet in the fuel addition valve holder 74, based on a detection signal from an outflow coolant temperature detection device 742. The temperature of the coolant (herein referred to as the effluent coolant temperature) is (estimated or) measured as the addition valve related temperature. The addition valve related temperature (outflow coolant temperature) is a temperature related to the fuel addition valve 61 (addition valve).

The coolant circulation passage 75 connects the intercooler 71 to the fuel addition valve holder 74. The coolant inside the coolant circulation passage 75 is pumped by the electric pump 73 and circulates within the coolant circulation passage 75 . The coolant circulation passage 75 includes a cold coolant pipe 75A, an upstream pipe 75BA, an IC distribution pipe 75BB, an FH distribution pipe 75BC, an IC return pipe 75CA, and an FH return pipe 75CB.

The cold coolant pipe 75A connects the intercooler radiator 72 and the electric pump 73. The coolant cooled by the intercooler radiator 72 flows into the cold coolant pipe 75A from the intercooler radiator 72, and further flows into the electric pump 73 from the cold coolant pipe 75A.

The coolant pressure feeding pipe 75B has an upstream pipe 75BA connected to the electric pump 73, and branches from the upstream pipe 75BA into an IC distribution pipe 75BB and an FH distribution pipe 75BC. IC distribution pipe 75BB connects upstream pipe 75BA and intercooler 71. The FH distribution pipe 75BC connects the upstream pipe 75BA and the fuel addition valve holder 74. The coolant pumped by the electric pump 73 flows from the electric pump 73 into the upstream pipe 75BA, and from the upstream pipe 75BA, the coolant branches and flows into the IC distribution pipe 75BB and the FH distribution pipe 75BC. The coolant that has flowed into the IC distribution pipe 75BB flows into the intercooler 71 from the IC distribution pipe 75BB. Further, the coolant that has flowed into the FH distribution pipe 75BC flows into the fuel addition valve holder 74 from the FH distribution pipe 75BC.

The IC return pipe 75CA connects the intercooler 71 and the intercooler radiator 72. The coolant flowing out from the intercooler 71 flows into the IC return pipe 75CA, and further flows into the intercooler radiator 72.

FH return pipe 75CB connects fuel addition valve holder 74 and IC return pipe 75CA. The coolant flowing out from the fuel addition valve holder 74 flows into the FH return pipe 75CB, further flows out from the FH return pipe 75CB into the IC return pipe 75CA, and flows into the intercooler radiator 72 from the IC return pipe 75CA.

As explained above, the coolant circulates within the coolant circulation passage 75. The coolant cooled by the intercooler radiator 72 flows into the electric pump 73 via the cold coolant pipe 75A. The coolant pumped from the electric pump 73 flows from the electric pump 73 into the intercooler 71 and the fuel addition valve holder 74 via the upstream pipe 75BA, the IC distribution pipe 75BB, and the FH distribution pipe 75BC. The coolant that has flowed into the intercooler 71 is heated by the intake air in the intercooler 71, and flows from the intercooler 71 into the intercooler radiator 72 via the IC return pipe 75CA. On the other hand, the coolant that has flowed into the fuel addition valve holder 74 is heated by the fuel addition valve holder 74 and flows from the fuel addition valve holder 74 into the intercooler radiator 72 via the FH return pipe 75CB and the IC return pipe 75CA. do.

Here, the upstream piping 75BA, the IC distribution piping 75BB, and the FH distribution piping 75BC, which are piping that connects the electric pump 73, intercooler 71, and fuel addition valve holder 74, are connected from the upstream piping 75BA to the IC distribution piping 75BB. It branches into FH distribution pipe 75BC. As a result, the coolant cooled by the intercooler radiator 72 is pumped by the electric pump 73 and flows from the electric pump 73 into the intercooler 71 and the fuel addition valve holder 74 in a branched manner. In each of the upstream pipe 75BA, the IC distribution pipe 75BB, and the FH distribution pipe 75BC, the cross-sectional area of the portion through which the coolant flows is constant from the upstream side to the downstream side. In the upstream pipe 75BA, the IC distribution pipe 75BB, and the FH distribution pipe 75BC, the ratio of the area of the section through which the coolant flows is expressed by the following (Formula 1).
IC distribution pipe 75BB:FH distribution pipe 75BC=9:1...(Formula 1)

By setting the ratio of (Equation 1), the flow rate of the coolant is set so that the flow rate distributed to the FH distribution pipe 75BC is smaller than the flow rate distributed to the IC distribution pipe 75BB. . That is, the coolant pumped from the electric pump 73 to the upstream pipe 75BA is distributed to the IC distribution pipe 75BB and the FH distribution pipe 75BC at the following ratio (Equation 2).
IC distribution pipe 75BB:FH distribution pipe 75BC=9:1...(Formula 2)

Usually, the volume of coolant in intercooler 71 is larger than the volume of coolant in fuel addition valve holder 74 (volume; intercooler 71 > fuel addition valve holder 74), so the amount of coolant required to cool intercooler 71 is , is larger than the amount of coolant required for cooling the fuel addition valve holder 74 (amount of coolant required for cooling; intercooler 71 > fuel addition valve holder 74). On the other hand, the flow rate of the coolant force-fed to the intercooler 71 via the IC distribution pipe 75BB is larger than the flow rate of the coolant force-fed to the fuel addition valve holder 74 (to the fuel addition valve 61) via the FH distribution pipe 75BC. By setting the flow rate ratio as in the ratio of (Equation 2), the coolant can be efficiently pressure-fed to the intercooler 71 and the fuel addition valve holder 74 (addition valve).

● [Processing procedure of control device 50 (Figures 3 to 5)]
Next, the processing procedure of the control device 50 will be explained. When the control device 50 (CPU of the control device 50 (see FIG. 1)) is started, it reads out the inflow coolant temperature/driving time characteristics from the EEPROM (see FIG. 1), stores it in the RAM (see FIG. 1), and further , for example, starts the process shown in FIG. 3 at predetermined time intervals (several tens of milliseconds). After starting the process shown in the flowchart in FIG. 3, the control device 50 advances the process to step S010.

In step S010, the control device 50 detects the outflow coolant temperature, and advances the process to step S020. Here, the outflow coolant temperature is the temperature of the coolant near the coolant outlet 74B, which is the coolant outlet in the fuel addition valve holder 74, as shown in FIG. The control device 50 detects the outflow coolant temperature based on a detection signal from the outflow coolant temperature detection device 742 provided near the coolant outlet 74B.

The coolant that has flowed into the fuel addition valve holder 74 from the coolant inlet 74A is heated within the fuel addition valve holder 74 by the heat of the fuel addition valve 61, and flows out of the fuel addition valve holder 74 from the coolant outlet 74B. . Therefore, the coolant near the coolant outlet 74B is the coolant that has been heated by the fuel addition valve 61 within the fuel addition valve holder 74. Therefore, it can be considered that the higher the temperature inside the fuel addition valve 61, the higher the outflow coolant temperature, which is the temperature of the coolant near the coolant outlet 74B.

Further, the outflow coolant temperature, which is the temperature of the coolant near the coolant outlet 74B of the fuel addition valve holder 74, corresponds to the addition valve-related temperature, which is the temperature related to the fuel addition valve 61 (addition valve). The control device 50 (CPU) that detects the outflow coolant temperature in step S010 detects the temperature of the coolant near the coolant outflow port 74B, which is the coolant outflow port in the fuel addition valve holder 74 (addition valve holder) (i.e., the outflow coolant temperature). This corresponds to the addition valve temperature detection unit 50A that (estimates or) measures the temperature) as the addition valve related temperature. In other words, the control device 50 (CPU) that detects the outflow coolant temperature in step S010 estimates or measures the outflow coolant temperature (addition valve related temperature), which is the temperature related to the fuel addition valve 61 (addition valve). This corresponds to the addition valve temperature detection section 50A.

In step S020, the control device 50 determines whether or not the fuel addition valve 61 needs to be cooled, and if it is determined that the fuel addition valve 61 needs to be cooled (Yes), the process proceeds to step S080. If it is determined that there is no need to cool the fuel addition valve 61 (No), the process advances to step S030.

Here, as described above regarding step S010, it can be considered that as the temperature inside the fuel addition valve 61 becomes higher, the outflow coolant temperature, which is the temperature of the coolant near the coolant outlet 74B, becomes higher. Therefore, in step S020, the control device 50 controls the cooling of the fuel addition valve 61 when the outflow coolant temperature (addition valve related temperature) is equal to or higher than a predetermined cooling start temperature (cooling start temperature≦outflow coolant temperature). It is determined that there is a need (step S020: Yes). On the other hand, in step S020, the control device 50 determines that if the outflow coolant temperature (addition valve related temperature) is less than the cooling start temperature (outflow coolant temperature<cooling start temperature), there is no need to cool the fuel addition valve 61 (step S020). S020: No).

In addition, in step S020, the control device 50 (CPU) that determines whether or not it is necessary to cool the fuel addition valve 61 cools the fuel addition valve 61 (addition valve) based on the outflow coolant temperature (addition valve related temperature). This corresponds to the additional valve cooling request determination unit 50B that determines whether or not cooling of the valve (valve) is necessary. More specifically, in step S020, the control device 50 (CPU) that determines whether or not it is necessary to cool the fuel addition valve 61 starts cooling when the outflow coolant temperature (addition valve related temperature) is a predetermined temperature. This corresponds to the addition valve cooling request determination unit 50B that determines that there is a need to cool the fuel addition valve 61 (addition valve) when the temperature exceeds the temperature.

When proceeding to step S030, the control device 50 detects various operating states of the internal combustion engine 10, and proceeds to step S040. Here, the control device 50 detects the operating state based on detection signals from various detection devices shown in FIG. 1. Further, the operating state detected by the control device 50 includes information on the temperature of the intake air whose temperature has been lowered by the intercooler 71 based on the detection signal from the intake air temperature detection device 23. That is, the operating state detected by the control device 50 includes, for example, the following information. The flow rate of air taken into the internal combustion engine 10 based on the detection signal from the intake flow rate detection device 21. The temperature of the intake air passing through the intake air flow rate detection device 21 based on the detection signal from the intake air temperature detection device 21A. The temperature of the intake air whose temperature has been lowered by the intercooler 71 based on the detection signal from the intake air temperature detection device 23. The amount of depression of the accelerator pedal based on the detection signal from the accelerator depression amount detection device 25. The rotation speed of the internal combustion engine 10 based on the detection signal from the rotation detection device 27 and the detection signal from the cylinder detection device 28.

In step S040, control device 50 determines whether or not intercooler 71 needs to be cooled based on the various operating states of internal combustion engine 10 detected in step S030, and determines whether intercooler 71 needs to be cooled. If it is determined that there is a need to cool the intercooler 71 (Yes), the process proceeds to step S060, and if it is determined that there is no need to cool the intercooler 71 (No), the process proceeds to step S050. Here, the lower the temperature of the coolant inside the intercooler 71, the cooler the intake air is, and the larger the amount of coolant that is pressure-fed by the electric pump 73 from the intercooler radiator 72 to the intercooler 71, the lower the temperature inside the intercooler 71. In turn, the intake air can be cooled more strongly. That is, the degree to which intake air is cooled by the intercooler 71 can be adjusted by adjusting the amount of coolant pumped from the intercooler radiator 72. The process of step S040 determines whether or not it is necessary to cool the intercooler 71 in order to set the amount of coolant pumped from the intercooler radiator 72 to control the combustion of fuel in the internal combustion engine 10. This is a process for determining.

Note that in step S040 and step S110, which will be described later, the control device 50 (CPU) determines whether or not it is necessary to cool the intercooler 71 based on the operating state of the internal combustion engine 10. This corresponds to an intercooler cooling request determination unit 50E that determines whether cooling of the intercooler 71 is necessary based on the state.

When the process proceeds to step S050, the control device 50 stops the operation of the electric pump 73, and ends the process shown in the flowchart of FIG. 3. In addition, in the process of step S050, the control device 50 determines in step S020 that there is no need to cool the fuel addition valve 61 (addition valve) (step S020: No), and further, in the subsequent step S040, the intercooler This is a process that is executed when it is determined that there is no need to cool 71 (step S040: No). That is, the process of step S050 is performed when there is no need to cool both the fuel addition valve 61 (addition valve) and the intercooler 71, that is, when it is necessary to pump coolant to cool the fuel addition valve 61 and the intercooler 71. Executed if there is no. Therefore, the operation of the electric pump 73 is stopped by the process of step S050.

The control device 50 (CPU) that stops the operation of the electric pump 73 in step S050 uses the addition valve cooling request determination unit 50B and the intercooler cooling request determination unit 50E to determine whether the addition valve needs to be cooled or not. If it is determined that there is no need for cooling (step S020: No followed by step S040: No), the electric pump stops the operation of the electric pump and stops the circulation of the coolant in the coolant circulation passage 75. This corresponds to the control section 50C.

When the process proceeds to step S060, the control device 50 determines the discharge flow rate at which the electric pump 73 pumps coolant in order to cool the intercooler 71, based on the various operating states of the internal combustion engine 10 detected in step S030. The discharge flow rate and discharge time to the intercooler 71, which are the discharge time and discharge time, are calculated, and the process proceeds to step S070. Here, in the process of step S060, the control device 50 calculates the discharge flow rate and discharge time to the intercooler 71 in order to control the combustion of fuel in the internal combustion engine 10.

Note that the control device 50 (CPU) that determines the discharge flow rate and drive time of the electric pump 73 to the intercooler 71 in step S060 also corresponds to the electric pump control unit 50C. In addition, in this specification, "the discharge flow rate and drive time of the electric pump 73 to the intercooler 71" is referred to as "the discharge flow rate and drive time to the intercooler 71", "the discharge flow rate and drive time to the intercooler 71", and "the discharge flow rate and drive time to the intercooler 71". It may also be written as ``discharge flow rate and driving time to intercooler''. Similarly, in this specification, "the discharge flow rate and drive time of the electric pump 73 for cooling the fuel addition valve 61" is referred to as "the discharge flow rate and drive time of the electric pump 73 for the fuel addition valve 61", and "the discharge flow rate and drive time of the electric pump 73 for cooling the fuel addition valve 61". It may also be written as "discharge flow rate and drive time for the addition valve 61", "discharge flow rate and drive time for the fuel addition valve 61", or "discharge flow rate and drive time for the addition valve".

In step S070, the control device 50 outputs a control signal to the electric pump 73 so that the electric pump 73 pumps the coolant at the discharge time and discharge time to the intercooler 71 calculated in step S060. The process shown in the flowchart ends. In addition, in step S070, the control device 50 determines that there is no need to cool the fuel addition valve 61 (addition valve) in step S020 (step S020: No), and then cools the intercooler 71 in the subsequent step S040. This process is executed when it is determined that cooling is necessary (step S040: Yes). When the process of step S070 is executed, there is a case where coolant is required to cool the intercooler 71 and there is no need to force-feed the coolant to cool the fuel addition valve 61. Therefore, in step S070, the control device 50 executes a process of outputting a control signal to the electric pump 73 so as to continue pumping the coolant for a discharge time and a discharge time to the intercooler 71.

In addition, in step S070, the addition valve cooling request determining unit 50B and the intercooler cooling request determining unit 50E determine that there is no need to cool the fuel addition valve 61 (addition valve) (step S020: No) and that the intercooler 71 does not need to be cooled. If it is determined that cooling is necessary (step S040: Yes), a process is executed to output a control signal to the electric pump 73 so as to continue pumping coolant for the discharge flow rate and driving time of the electric pump 73 to the intercooler 71. The control device 50 (CPU) (which controls the electric pump 73 based on the discharge flow rate and drive time of the electric pump 73 with respect to the intercooler 71) corresponds to the electric pump control section 50C.

When proceeding to step S080, the control device 50 detects the inflow coolant temperature, and proceeds to step S090. Here, the inflow coolant temperature is the temperature of the coolant near the coolant inlet 74A, which is the coolant inlet 74A in the fuel addition valve holder 74, as shown in FIG. That is, the inflow coolant temperature is the temperature of the coolant flowing into the fuel addition valve holder 74. The control device 50 detects the inflow coolant temperature based on a detection signal from the inflow coolant temperature detection device 741 provided near the coolant inlet 74A.

Here, the higher the kinematic viscosity of the coolant, the more difficult the coolant is to flow, and the kinematic viscosity changes depending on the temperature of the coolant. The kinematic viscosity of the coolant near the coolant inlet 74A is the kinematic viscosity of the coolant flowing into the fuel addition valve holder 74, and the higher the kinematic viscosity, the more difficult it becomes for the coolant to flow into the fuel addition valve holder 74.

Note that in step S080, the control device 50 (CPU) that detects the inflow coolant temperature estimates the inflow coolant temperature, which is the temperature of the coolant near the fuel addition valve holder 74 in the fuel addition valve holder 74 (addition valve holder). Alternatively, it corresponds to the inflow coolant temperature detection section 50D for measurement.

When the process proceeds to step S090, the control device 50 determines the discharge flow rate and discharge time for the electric pump 73 to pump coolant to cool the fuel addition valve 61 (addition valve). is set, the drive time for the fuel addition valve is calculated based on the set discharge flow rate, the inflow coolant temperature detected in step S080, and the inflow coolant temperature/drive time characteristics stored in advance, and the drive time for the fuel addition valve is calculated. The process advances to S100. Here, in step S090, the control device 50 sets the discharge flow rate for the fuel addition valve 61 (addition valve) in order to cool the fuel addition valve 61 (addition valve), and Calculate the drive time for As mentioned above, when the control device 50 (CPU of the control device 50 (see FIG. 1)) is started, it reads out the inflow coolant temperature/driving time characteristics from the EEPROM (see FIG. 1) and stores them in the RAM (see FIG. 1). Remember.

FIG. 4 shows an example of inflow coolant temperature/driving time characteristics. As shown in FIG. 4, the inflow coolant temperature/driving time characteristics are determined for each of the discharge flow rates (in FIG. 4, there are two discharge flow rates A and B) for the plurality of fuel addition valves 61 (addition valves). It contains data of driving time values measured in advance for various inflow coolant temperatures in the form of a map.

When the electric pump 73 pumps coolant at the discharge flow rate during the drive time, the amount of coolant pumped by the electric pump 73 (= drive time x discharge flow rate) is equal to the total amount of coolant in the fuel addition valve holder 74 replaced. The driving time and the discharge flow rate are set so that the prescribed amount can be achieved. The control device 50 is configured to correspond to each of a plurality of discharge flow rates (in FIG. 4, there are two discharge flow rates A and B) so that the discharge flow rate can be changed according to the operating state of the internal combustion engine 10. , stores an inflow coolant temperature/drive time characteristic in which a drive time corresponding to the inflow coolant temperature is set.

For example, the driving time is determined by the kinematic viscosity of the coolant (coolant flowing into the fuel addition valve holder 74) near the coolant inlet 74A of the fuel addition valve holder 74 (addition valve holder), as shown in the following (Equation 3). Correct based on.
Driving time (T°C) = Standard driving time (20°C) x Kinematic viscosity (T°C) / Standard kinematic viscosity (20°C) (Formula 3)
In (Equation 3), the drive time (T°C) is the drive time when the inflow coolant temperature is T°C. The reference driving time (20°C) is the driving time when the inflow coolant temperature is 20°C. Kinematic viscosity (T°C) is the kinematic viscosity of the coolant at T°C. Kinematic viscosity (20°C) is the kinematic viscosity of the coolant at 20°C. Generally, the higher the temperature of the coolant, the lower the kinematic viscosity of the coolant. Therefore, as shown in FIG. 4, in the inflow coolant temperature/driving time characteristic, the higher the inflow coolant temperature, the shorter the driving time.

In step S090, the control device 50 first sets the discharge flow rate for the fuel addition valve 61 (addition valve) (for example, sets the discharge flow rate to A of the discharge flow rates A and B in FIG. 4). Next, the drive time is calculated based on the inflow coolant temperature/drive time characteristic corresponding to the set discharge flow rate and the inflow coolant temperature detected in step S080. In this way, the control device 50 controls the drive time for the fuel addition valve based on the set discharge flow rate, the inflow coolant temperature detected in step S080, and the pre-stored inflow coolant temperature/drive time characteristics. Do what you calculate.

In addition, in step S090, control is performed to calculate the drive time for the fuel addition valve based on the set discharge flow rate, the inflow coolant temperature detected in step S080, and the inflow coolant temperature/drive time characteristics stored in advance. The device 50 (CPU) corresponds to the electric pump control section 50C. When the control device 50 determines in step S020 that there is a need to cool the fuel addition valve 61 (addition valve) (step S020: Yes), the electric pump control unit 50C controls the fuel addition valve 61 (addition valve). The drive time is determined based on the discharge flow rate, the inflow coolant temperature, and the inflow coolant temperature/driving time characteristics (step S090), and the drive time is determined based on the determined discharge flow rate and drive time. The electric pump 73 is controlled (step S070 and step S140, which will be described later).

Further, in step S090, the electric pump control unit 50C corrects the drive time based on the kinematic viscosity of the coolant near the coolant inlet 74A, which is the coolant inlet in the fuel addition valve holder 74 (addition valve holder). Furthermore, as described above, when the electric pump 73 pumps coolant at the discharge flow rate during the drive time, the amount of coolant to be pumped by the electric pump 73 during the drive time (= drive time x discharge flow rate) is The driving time and the discharge flow rate are set so that the amount of coolant in the fuel addition valve holder 74 is a specified amount that allows the entire amount to be replaced.

In step S100, control device 50 detects various operating states of internal combustion engine 10, and advances the process to step S110. Here, the control device 50 detects the operating state in the same manner as in step S030 described above. That is, the operating state detected by the control device 50 includes, for example, the following information. The flow rate of air taken into the internal combustion engine 10, the temperature of the intake air passing through the intake air flow rate detection device 21, the temperature of the intake air whose temperature has been lowered by the intercooler 71, the amount of depression of the accelerator pedal, and the rotation speed of the internal combustion engine 10.

In step S110, control device 50 determines whether or not intercooler 71 needs to be cooled based on the various operating states of internal combustion engine 10 detected in step S100, and determines whether intercooler 71 needs to be cooled. If it is determined that there is a need to cool the intercooler 71 (Yes), the process proceeds to step S120, and if it is determined that there is no need to cool the intercooler 71 (No), the process proceeds to step S140. Here, the control device 50 determines whether or not it is necessary to cool the intercooler 71 in the same manner as in step S040 described above. Further, in step S110, the control device 50 (CPU) that determines whether or not it is necessary to cool the intercooler 71 based on the operating state of the internal combustion engine 10, based on the operating state of the internal combustion engine 10, This corresponds to an intercooler cooling request determination unit 50E that determines whether or not cooling of the intercooler 71 is necessary.

Note that the process of step S110 is a process that is executed after determining in step S020 that it is necessary to cool the fuel addition valve 61 (step S020: Yes). Therefore, if the control device 50 determines in step S110 that there is no need to cool the intercooler 71 (step S110: No), coolant is transported from the electric pump 73 to cool the intercooler 71. Although not necessary, it is necessary to cool the fuel addition valve 61. Therefore, when the control device 50 determines in step S110 that there is no need to cool the intercooler 71 (step S110: No), in the subsequent step S140, the control device 50 controls the fuel addition valve 61 In order to cool the fuel addition valve 61 (addition valve), the discharge flow rate and drive time for the fuel addition valve 61 (addition valve) determined in advance in step S090, and a control signal to the electric pump 73 so that the electric pump 73 continues to pump coolant are sent. Output. Here, the control device 50 determines in the addition valve cooling request determination unit and the intercooler cooling request determination unit that there is a need to cool the fuel addition valve 61 (addition valve) (step S020: YES) and that the intercooler If it is determined that there is no need for cooling (step S110: NO), the discharge flow rate and drive time of the electric pump 73 for the fuel addition valve 61 (addition valve) are determined (step S090), The control device 50 (CPU) that controls the electric pump 73 based on the discharge flow rate and driving time (step S140) corresponds to the electric pump control section 50C.

When the process proceeds to step S120, the discharge flow rate and discharge time at which the electric pump 73 pumps the coolant in order to cool the intercooler 71 are determined based on the various operating states of the internal combustion engine 10 detected in step S100. , the discharge flow rate and discharge time to the intercooler 71 are calculated, and the process proceeds to step S070. Here, the discharge flow rate and discharge time for the intercooler 71 are calculated in the same manner as the process executed in step S060. The control device 50 (CPU) that determines the discharge flow rate and driving time of the electric pump 73 to the intercooler 71 in step S120 also corresponds to the electric pump control section 50C.

In step S130, control device 50 determines that the discharge flow rate to fuel addition valve 61 determined in step S090 is greater than or equal to the discharge flow rate to intercooler 71 determined in step S120 (discharge flow rate to fuel addition valve 61≧discharge flow rate to intercooler 71). If it is determined that the discharge flow rate to the fuel addition valve 61 is greater than or equal to the discharge flow rate to the intercooler 71 (discharge flow rate to the fuel addition valve 61 ≧ discharge flow rate to the intercooler 71) If Yes), the process advances to step S140, and if it is determined that the discharge flow rate to the fuel addition valve 61 is less than the discharge flow rate to the intercooler 71 (discharge flow rate to the fuel addition valve 61<discharge flow rate to the intercooler 71) (No ), the process advances to step S070.

Note that if it is determined in step S130 that the discharge flow rate to the fuel addition valve 61 is not greater than or equal to the discharge flow rate to the intercooler 71 (discharge flow rate to the fuel addition valve 61<discharge flow rate to the intercooler 71) (step S130: No), In the subsequent step S070, the control device 50 sends a control signal to the electric pump 73 so that the electric pump 73 continues to pump coolant at the discharge flow rate and driving time to the intercooler 71 determined in step S120. Output.

When the process proceeds to step S140, the control device 50 outputs a control signal to the electric pump 73 so that the electric pump 73 pumps the coolant at the discharge time and discharge flow rate to the fuel addition valve 61 determined in step S090. Then, the process shown in the flowchart of FIG. 3 ends. Here, as described above, in step S090, when the electric pump 73 pumps coolant at the discharge flow rate during the drive time, the amount of coolant to be pumped by the electric pump 73 during the drive time (= drive time The driving time and the discharge flow rate are set so that the amount (discharge flow rate) becomes a specified amount that allows the entire amount of coolant in the fuel addition valve holder 74 to be replaced. When the addition valve cooling request determination unit 50B determines that there is a need to cool the addition valve (step S020: Yes), the control device 50 causes the electric pump control unit 50C to drain the entire amount of coolant in the addition valve holder. The electric pump is caused to pump a specified amount of coolant that can be replaced (step S140).

Note that when the addition valve cooling request determination unit 50B determines that there is a need to cool the fuel addition valve 61 (addition valve) (step S020: Yes), the control device 50 causes the electric pump control unit 50C to: A specified amount of coolant is forced into the electric pump (step S070 or step S140). Further, when the addition valve cooling request determination unit 50B determines that there is a need to cool the fuel addition valve 61 (addition valve) (step S020: Yes), the control device 50 (CPU) controls the electric pump control unit 50C. At step S090, the discharge flow rate and drive time of the electric pump corresponding to the specified amount are determined, and the electric pump is controlled based on the determined discharge flow rate and drive time (steps S100 to S140, step S070).

Further, the control device 50 determines in the addition valve cooling request determination unit 50B and the intercooler cooling request determination unit 50E that there is a need to cool both the fuel addition valve 61 (addition valve) and the intercooler 71. In the case of determination (step S110: Yes), the discharge flow rate and drive time of the electric pump 73 to the fuel addition valve 61 (addition valve) (step S090), and the discharge flow rate and drive time of the electric pump to the intercooler 71 (step S090) are determined. Step S120), and the control device 50 controls the electric pump based on the discharge flow rate and drive time (step S130) on the side where the amount of coolant discharged from the electric pump 73 increases (step S070 or step S0140). (CPU) corresponds to the electric pump control unit 50C.

● [About the effects of the cooling system 70 of this embodiment (FIGS. 1 to 3)]
Next, the effects of the cooling system 70 of this embodiment will be explained using FIG. 5. In the process shown in the flowchart of FIG. 3, if it is not necessary to cool both the fuel addition valve 61 and the intercooler 71 (step S040: No), the operation of the electric pump 73 is stopped (step S050). In addition, if it is necessary to cool either the fuel addition valve 61 or the intercooler 71 (step S110: No or step S040: Yes), the discharge flow rate and discharge time for the side that needs to be cooled are determined. , controls the electric pump 73 (step S140 or step S070).

On the other hand, if both the fuel addition valve 61 and the intercooler 71 need to be cooled (step S110: Yes), the discharge flow rate that increases between the discharge flow rate to the fuel addition valve and the discharge flow rate to the intercooler 71 is determined. The electric pump is controlled based on the flow rate and drive time (step S130) (step S070 or step S0140). As described above, in the process shown in the flowchart of FIG. It is designed to be pumped to both.

In the process shown in the flowchart of FIG. 3, since there is no need to cool the intake air in the intercooler 71, if there is no need to forcefully feed coolant to the intercooler 71 (step S040: No or step S110: No), the following steps are performed: Processing is performed as follows. FIG. 5 shows the temporal changes in the coolant outflow temperature (temperature related to the addition valve), the internal temperature of the intercooler, and the electric pump in one example when there is no need to pump coolant to the intercooler 71. An outline of ON and OFF is shown. As shown in FIG. 5, at time T1, the coolant outflow temperature (addition valve related temperature) is lower than the cooling start temperature, so the control device 50 determines that there is no need to cool the fuel addition valve 61 (step S020 : No), and since there is no need to pump coolant to the intercooler 71 (step S040: No), the operation of the electric pump 73 is stopped (step S050).

As shown in FIG. 2, the fuel addition valve 61 is provided in the exhaust pipe 12C through which high-temperature exhaust gas flows, and is heated by the exhaust gas flowing through the exhaust pipe 12C and the exhaust pipe 12C. The fuel addition valve holder 74 that holds the fuel addition valve 61 and is filled with coolant is heated by the fuel addition valve 61. As a result, between time T1 and time T2 shown in FIG. 5, the coolant outflow temperature, which is the temperature of the coolant near the coolant outflow port 74B of the fuel addition valve holder 74, increases, and at time T2, the coolant outflow temperature increases. The temperature becomes the cooling start temperature. Since the coolant outflow temperature is lower than the cooling start temperature between time T1 and time T2, the control device 50 continues to stop the operation of the electric pump 73 (step S050).

Further, between time T1 and time T2, intercooler 71 is heated by the heat of the intake air, and the internal temperature of intercooler 71 gradually increases. In the graph of the temporal change in the internal temperature of the intercooler 71 in FIG. 5, a recommended upper limit temperature and a recommended lower limit temperature are shown. If the internal temperature of intercooler 71 is higher than the recommended upper limit temperature, the temperature of intercooler 71 is too high, and control device 50 determines that intercooler 71 needs to be cooled (step S040: Yes). , or step S110: Yes). Moreover, when the internal temperature of intercooler 71 is lower than the recommended lower limit temperature, the internal temperature of intercooler 71 is too low, so that intake air is excessively cooled by intercooler 71. Therefore, when there is no need to pump coolant to the intercooler 71, the internal temperature of the intercooler 71 is lower than the recommended upper limit temperature and higher than the recommended lower limit temperature (recommended lower limit temperature < intercooler 71 internal temperature). Internal temperature < recommended upper limit temperature) is required.

As described above, at time T2, the coolant outflow temperature becomes the cooling start temperature. The cooling start temperature is the allowable upper limit temperature of the coolant outflow temperature. At time T2, since the coolant outflow temperature is equal to or higher than the cooling start temperature (cooling start temperature≦outflow coolant temperature), the control device 50 determines that it is necessary to cool the fuel addition valve 61 (step S020: Yes), and since the internal temperature of intercooler 71 is lower than the recommended upper limit temperature, it is determined that there is no need to cool intercooler 71 (step S110: No). Then, the control device 50 controls the electric pump 73 based on the discharge flow rate and driving time for the fuel addition valve 61 (step S140). As a result, from time T2 until time T3 when the drive time for fuel addition valve 61 has elapsed, coolant is pumped from electric pump 73 to intercooler 71 and fuel addition valve holder 74, and intercooler 71 and fuel addition valve 61 are cooled. be done. As a result, from time T2 to time T3, the coolant outflow temperature and the internal temperature of intercooler 71 decrease.

Here, when the electric pump 73 pumps coolant at the discharge flow rate to the fuel addition valve 61 during the drive time to the fuel addition valve 61, the amount of coolant to be pumped to the electric pump 73 during the drive time (= drive The driving time and the discharge flow rate for the fuel addition valve 61 are set so that (time×discharge flow rate) becomes a specified amount that allows the entire amount of coolant in the fuel addition valve holder 74 to be replaced. Therefore, the fuel addition valve 61 is reliably cooled between time T2 and time T3.

At time T3, since the coolant outflow temperature (addition valve related temperature) is lower than the cooling start temperature, the control device 50 determines that there is no need to cool the fuel addition valve 61 (step S020: No), and further cools the intercooler. Since there is no need to pump coolant to the pump 71 (step S040: No), the operation of the electric pump 73 is stopped (step S050).

Then, in the same way as between time T1 and time T2, the coolant outflow temperature and the internal temperature of the intercooler 71 increase from time T3 to time T4, and at time T4, the coolant outflow temperature becomes the cooling start temperature again. . Then, like time T2, at time T4, the control device 50 again controls the electric pump 73 by controlling the discharge flow rate and driving time for the fuel addition valve 61. As a result, the coolant outflow temperature and the internal temperature of the intercooler 71 decrease again from time T4 until time T5 when the driving time for the fuel addition valve 61 has elapsed. After time T5, the control device 50 performs the same control as from time T3 to time T5, and also controls the time change of the coolant outflow temperature (addition valve related temperature) in the same way as from time T3 to time T5. , the time change in the internal temperature of the intercooler, and the ON/OFF of the electric pump 73 are repeated.

As explained above, the cooling system 70 of this embodiment switches the electric pump ON or OFF depending on whether the coolant outflow temperature is equal to or higher than the cooling start temperature which is the allowable upper limit temperature. On the other hand, in the cooling system of Comparative Example 1 shown in FIG. This is a cooling system that performs control to stop the operation of 73. As shown in FIG. 5, in the cooling system of Comparative Example 1, when there is a period in which it is not necessary to forcefully feed coolant to the intercooler 71, the exhaust gas flowing through the exhaust pipe 12C and the exhaust pipe 12C (see FIG. 2) As the fuel addition valve 61 continues to be heated, the coolant outflow temperature continues to rise beyond the allowable upper limit temperature (dotted chain line after time T2 in FIG. 5). As a result, the more the fuel addition valve 61 is damaged by heat, the higher the temperature of the fuel addition valve 61 may become.

Therefore, the cooling system of Comparative Example 2 shown in FIG. The cooling system shall be That is, in the cooling system of Comparative Example 2, when there is no need to force-feed coolant to the intercooler 71, when the coolant outflow temperature becomes equal to or higher than the cooling start temperature, which is the allowable upper limit temperature, the electric pump is operated at the discharge flow rate to the fuel addition valve 61. 73 starts pumping the coolant, and thereafter, the electric pump 73 continues pumping the coolant at the discharge flow rate to the fuel addition valve 61.

As shown in FIG. 5, in the cooling system of Comparative Example 2, the coolant outflow temperature becomes equal to or higher than the cooling start temperature, which is the allowable upper limit temperature, at time T2, and after time T2, the coolant flows into the electric pump 73 at the discharge flow rate to the fuel addition valve 61. continues to be pumped. In the cooling system of Comparative Example 2, since the coolant outflow temperature continues to decrease after time T2, there is no fear that the fuel addition valve 61 will be damaged by heat. However, since the electric pump 73 continues to pump coolant to the intercooler 71 after time T2, the internal temperature of the intercooler 71 drops below the recommended temperature, and the intake air is excessively cooled by the intercooler 71. There is a risk. As described above, in the cooling system of Comparative Example 1, the fuel addition valve 61 may be excessively heated, and in the cooling system of Comparative Example 2, the intake air may be excessively cooled by the intercooler 71.

On the other hand, the cooling system 70 of the present embodiment cools the fuel addition valve 61 and the intercooler 71 when the coolant outflow temperature is equal to or higher than the cooling start temperature which is the allowable upper limit temperature (cooling start temperature ≦ outflow coolant temperature). When the coolant outflow temperature is less than the cooling start temperature (outflow coolant temperature<cooling start temperature), the operation of the electric pump 73 is stopped. Therefore, when there is no need to cool the intake air with the intercooler 71, coolant is not constantly pumped from the electric pump 73 in order to cool the fuel addition valve 61 (addition valve). Thereby, when there is no need to force-feed coolant to intercooler 71, fuel addition valve 61 (addition valve) can be cooled while suppressing excessive cooling of intake air by intercooler 71.

The effects of the cooling system 70 of the internal combustion engine 10 according to the embodiment in the case where there is no need to cool the intake air with the intercooler 71 have been described above using FIG. 5 . The cooling system 70 for the internal combustion engine 10 of this embodiment has the effects described below.

In the cooling system 70, when the electric pump 73 pumps coolant, the coolant cooled by the intercooler radiator 72 is pumped to both the intercooler 71 and the fuel addition valve 61 (addition valve), and one electric pump 73 pumps the coolant. Coolant is fed under pressure to the intercooler 71 and the fuel addition valve 61 (addition valve). In this way, in the cooling system 70, one electric pump 73 serves as both an electric pump for the intercooler 71 and an electric pump for the fuel addition valve 61 (addition valve) for pumping coolant. Thereby, it is possible to further save space and reduce the number of parts of the cooling system 70, and in turn, it is possible to further save space and reduce the number of parts of the internal combustion engine 10.

In order to cool the fuel addition valve 61 (addition valve), the control device 50 causes the electric pump 73 to force-feed the coolant based on the addition valve related temperature in the addition valve cooling request determination unit 50B. This is done when it is determined that cooling of 61 (addition valve) is necessary. Therefore, even when there is no need to cool the intake air with the intercooler 71, the reason why the electric pump 73 pumps the coolant is because the addition valve cooling request determination unit 50B controls the cooling of the fuel addition valve 61 (addition valve). It is only necessary to pump the coolant from the electric pump 73 when it is determined that it is necessary, and the coolant is not always pumped. Thereby, when there is no need to force-feed coolant to the intercooler 71, it is possible to prevent the intercooler 71 from excessively cooling the intake air. Therefore, the cooling system 70 can further save space and reduce the number of parts, and also prevents the intercooler 71 from excessively cooling the intake air when there is no need to pump coolant to the intercooler 71. The fuel addition valve 61 (addition valve) can be cooled while suppressing.

In addition, the control device 50 allows the addition valve cooling request determination unit 50B to simply determine whether or not the addition valve related temperature exceeds the cooling start temperature which is a predetermined temperature. ) can determine whether or not cooling is necessary. Therefore, the control device 50 can easily determine whether or not cooling of the fuel addition valve 61 (addition valve) is necessary.

In addition, since the coolant is heated in the fuel addition valve holder 74 (addition valve holder) that accommodates the fuel addition valve 61 (addition valve) by the heat of the fuel addition valve 61 (addition valve), the fuel addition valve holder 74 ( The addition valve-related temperature, which is the estimated or measured temperature of the coolant near the coolant outlet of the addition valve holder), tends to change depending on the temperature of the fuel addition valve 61 (addition valve). Then, the control device 50 determines whether cooling of the fuel addition valve 61 (addition valve) is necessary or not based on the addition valve-related temperature that tends to change depending on the temperature of the fuel addition valve 61 (addition valve). Therefore, the control device 50 can more accurately determine whether or not cooling of the fuel addition valve 61 (addition valve) is necessary.

Further, when the control device 50 determines that there is a need to cool the fuel addition valve 61 (addition valve), the electric pump control unit 50C replaces the entire amount of coolant in the fuel addition valve holder 74 (addition valve holder). The electric pump 73 is caused to pump a specified amount of coolant that can be used. As a result, the entire amount of coolant in the fuel addition valve holder 74 (addition valve holder) is replaced, so that the coolant in the fuel addition valve holder 74 (addition valve holder) is cooled more reliably. Consequently, the cooling system 70 can reliably cool the fuel addition valve 61 (addition valve) when it is necessary to cool the fuel addition valve 61 (addition valve).

Further, when the control device 50 determines that there is a need to cool the fuel addition valve 61 (addition valve), the electric pump control unit 50C controls the discharge flow rate and drive time (fuel The discharge flow rate and drive time for the addition valve 61 are determined, and the electric pump 73 is controlled based on the determined discharge flow rate and drive time. Further, the flow rate of the coolant pumped from the electric pump 73 to the intercooler 71 is determined by the discharge flow rate of the electric pump 73. The greater the discharge flow rate of the electric pump 73, the greater the flow rate of the coolant pressure-fed from the electric pump 73 to the intercooler 71.

Here, the control device 50 can appropriately set the discharge flow rate of the electric pump 73 (the discharge flow rate to the fuel addition valve 61). As a result, the control device 50 determines that there is no need to forcefully feed coolant to the intercooler 71 and that there is a need to cool the fuel addition valve 61 (addition valve). It becomes easy to adjust the discharge flow rate of the electric pump 73 for cooling the intake air (addition valve) to an amount that does not excessively cool the intake air by the intercooler 71. By being able to adjust the discharge flow rate in this way, the cooling system 70 determines that there is no need to pump coolant to the intercooler 71, and that there is a need to cool the fuel addition valve 61 (addition valve). In addition, it becomes easy to cool the fuel addition valve 61 (addition valve) while suppressing excessive cooling of intake air by the intercooler 71.

Further, the control device 50 controls the electric pump control unit 50C to control the kinematic viscosity of the coolant near the coolant inlet 74A, which is the inlet of the coolant in the fuel addition valve holder 74 (addition valve holder). Correct the drive time (for 61). Here, the higher the kinematic viscosity of the coolant, the more difficult the coolant is to flow. Since the kinematic viscosity of the coolant near the coolant inlet 74A of the fuel addition valve holder 74 (addition valve holder) is the kinematic viscosity of the coolant flowing into the fuel addition valve holder 74 (addition valve holder), this kinematic viscosity The higher the value, the more difficult it becomes for coolant to flow into the fuel addition valve holder 74 (addition valve holder). The control device 50 corrects the drive time (with respect to the fuel addition valve 61) based on the kinematic viscosity of the coolant near the coolant inlet 74A of the fuel addition valve holder 74 (addition valve holder). The amount of coolant necessary for cooling the fuel addition valve (addition valve) can be more accurately pumped to the fuel addition valve holder 74 (addition valve holder). Therefore, the cooling system 70 can cool the fuel addition valve 61 (addition valve) more reliably.

Further, the control device 50 stores inflow coolant temperature/driving time characteristics in association with discharge flow rate. The control device 50 can read the inflow coolant temperature/driving time characteristics and easily determine the driving time from the read inflow coolant temperature/driving time characteristics. In addition, the inflow coolant temperature/driving time characteristic is such that the driving time for the fuel addition valve 61 (addition valve) is set according to the inflow coolant temperature related to the kinematic viscosity of the coolant, and the inflow coolant temperature/driving time characteristic is The determined drive time for the fuel addition valve 61 (addition valve) has been corrected based on the kinematic viscosity. Therefore, when the control device 50 determines that there is a need to cool the fuel addition valve 61 (addition valve), the control device 50 easily and quickly adjusts the driving time for the fuel addition valve 61 (addition valve) corrected based on the kinematic viscosity. It can be calculated as follows.

The control device 50 also controls the discharge flow rate of the electric pump to the intercooler necessary for cooling the intercooler 71 and the fuel addition valve 61 of the electric pump 73 necessary for cooling the fuel addition valve 61 (addition valve). Since the electric pump 73 is controlled based on the discharge flow rate for the (addition valve) and the side with the larger discharge flow rate, the intercooler 71 and the fuel addition valve 61 (addition valve) can be reliably cooled. In addition, when there is no need to cool the intercooler 71, the coolant is forcedly fed (discharged) from the electric pump 73 when it is determined that there is a need to cool the fuel addition valve 61 (addition valve). , if it is determined that there is no need to cool the fuel addition valve 61 (addition valve), the cooling is not performed. In this way, when there is no need to cool the intercooler 71, the coolant is forcedly fed (discharged) from the electric pump 73 only when it is necessary to cool the fuel addition valve 61 (addition valve). Thereby, when there is no need to force-feed coolant to intercooler 71, excessive cooling of intake air by intercooler 71 can be reliably suppressed.

●[Other embodiments]
The internal combustion engine control device of the present invention is not limited to the configuration, shape, structure, etc. of the cooling system 70 of the internal combustion engine 10 described in the embodiment described above, and various changes and additions can be made without changing the gist of the present invention. , can be deleted.

In the cooling system 70 of the embodiment described above, the intercooler 71 and the fuel addition valve holder 74 are connected to the coolant circulation passage 75, and the objects to be cooled by pumping the coolant are the intercooler 71 and the fuel addition valve 61. . Here, instead of the addition valve holder 74 that holds the fuel addition valve 61 connected to the coolant circulation passage 75, a urea water addition valve holder (not shown) that holds the urea water addition valve 62 similar to the fuel addition valve holder 74 is used. The intercooler 71 and the urea water addition valve 62 may be connected to the coolant circulation passage 75 to cool the coolant by feeding the coolant under pressure. Further, as described below, the cooling system 70 includes an intercooler 71, a fuel addition valve 61, a urea water addition valve 62, which is a type of addition valve, and a urea water addition valve 62, which is a type of addition valve. It may be configured as an addition valve 62.

For example, as shown in FIG. 6, a urea water addition valve holder 76 similar to the fuel addition valve holder 74 holds the urea water addition valve 62, and an outflow coolant temperature detection device 762 similar to the outflow coolant temperature detection device 742 is connected to the urea water addition valve holder 76. Provided for the water addition valve holder 76. Furthermore, the FH distribution pipe 75BC (see FIG. 1) in which the fuel addition valve 61 is provided is extended to the urea water addition valve holder 76 and connected to the urea water addition valve holder 76, and the FH return pipe 75CB is also connected to the urea water addition valve holder 76. It may be extended to the urea water addition valve holder 76. In this configuration, as shown in FIG. 6, a fuel addition valve holder 74 and a urea water addition valve holder 76 are provided in series in the FH distribution pipe 75BC.

Further, for example, in FIG. 6, the fuel addition valve holder 74 and the urea water addition valve holder 76 are connected in series to the FH distribution pipe 75BC of the coolant circulation passage 75, but the cooling system of the present invention is shown in FIG. 7, a cooling system may be provided in which a fuel addition valve holder 74 and a urea water addition valve holder 76 are connected in parallel to a coolant circulation passage 75.

Further, the control device 50 may perform control to set the discharge flow rate to the fuel addition valve 61 (addition valve) to one type of discharge flow rate prepared in advance. Further, the control device 50 may perform control to select and set the discharge flow rate for the fuel addition valve 61 (addition valve) from among several types (values) of discharge flow rates. Further, the control device 50 performs stepless variable control to appropriately set the discharge flow rate to the fuel addition valve 61 (addition valve) from a discharge flow rate within a predetermined range (for example, 1 ml/min to 500 ml/min). You may do so.

As described above using FIG. 2, the control device 50 of the cooling system 70 of the embodiment measures the inflow coolant temperature using the inflow coolant temperature detection device 741 in the inflow coolant temperature detection section 50D. Here, the inflow coolant temperature is the temperature of the coolant near the coolant inlet 74A in the fuel addition valve holder 74 (addition valve holder). The inflow coolant temperature detection unit 50D (control device 50) may measure or estimate the inflow coolant temperature. The inflow coolant temperature detection unit 50D (control device 50) may measure the inflow coolant temperature using a temperature detection device provided at a location different from the inflow coolant temperature detection device 741, or may measure the inflow coolant temperature using a temperature detection device provided at a different location from the inflow coolant temperature detection device 741. It may be estimated instead of measured. For example, the inflow coolant temperature detection unit 50D (control device 50) responds to a detection signal from a temperature detection device (for example, the exhaust gas temperature detection device 36A) provided at a different location from the inflow coolant temperature detection device 741. Based on this, the inflow coolant temperature may be estimated.

Further, as described above using FIG. 2, the control device 50 of the cooling system 70 of the embodiment uses the addition valve temperature detection unit 50A to detect the outflow coolant temperature based on the detection signal from the outflow coolant temperature detection device 742. is measured as the addition valve related temperature (outflow coolant temperature = addition valve related temperature). Here, the outflow coolant temperature is the addition valve related temperature, and the outflow coolant temperature is the temperature of the coolant near the coolant outflow port 74B, which is the coolant outflow port in the fuel addition valve holder 74. The addition valve temperature detection unit 50A (control device 50) may measure or estimate the outflow coolant temperature (addition valve related temperature). The addition valve temperature detection unit 50A (control device 50) may measure the outflow coolant temperature (addition valve related temperature) using a temperature detection device provided at a location different from the outflow coolant temperature detection device 742. However, it may be estimated instead of measured. For example, the control device 50 receives a detection signal from a temperature detection device (for example, the exhaust gas temperature detection device 36A) provided at a location different from the outflow coolant temperature detection device 742 in the addition valve temperature detection section 50A. Based on this, the outflow coolant temperature (addition valve related temperature) may be estimated.

In addition, in the cooling system 70 of the embodiment, when the addition valve cooling request determination unit 50B of the control device 50 determines that the addition valve-related temperature exceeds the cooling start temperature, the cooling of the fuel addition valve 61 (addition valve) is stopped. Although it is determined that there is a need to cool the fuel addition valve 61 (addition valve), it is not necessary to determine that there is a need to cool the fuel addition valve 61 (addition valve) when the addition valve-related temperature exceeds the cooling start temperature. For example, the addition valve cooling request determination unit 50B of the control device 50 may determine that there is a need to cool the fuel addition valve 61 (addition valve) when the addition valve-related temperature continues to rise for a predetermined period of time.

Further, in the cooling system 70 of the embodiment, the fuel addition valve 61 (addition valve) is housed in a fuel addition valve holder 74 filled with coolant, and the addition valve temperature detection unit 50A of the control device 50 detects the coolant. The temperature of the coolant near the outlet 74B is measured as the addition valve related temperature, but instead of having the fuel addition valve holder 74, the cooling system 70 has a fuel addition valve 61 (which has the same function as the fuel addition valve holder 74). addition valve).

Further, in the cooling system 70 of the embodiment, when the control device 50 determines in the addition valve cooling request determination unit 50B that there is a need to cool the fuel addition valve 61 (addition valve) (step S020 in FIG. 3: YES), the electric pump control unit 50C causes the electric pump 73 to force-feed a specified amount of coolant that can replace the entire amount of coolant in the fuel addition valve holder 74 (step S140 in FIG. 3). Here, the prescribed amount of coolant to be pumped to the electric pump 73 does not have to be an amount that allows the entire amount of coolant in the fuel addition valve holder 74 to be replaced; for example, 50% of the coolant in the fuel addition valve holder 74 can be replaced. It may be an amount that can be replaced, or, for example, it may be an amount that allows 80% or 90% of the coolant in the fuel addition valve holder 74 to be replaced.

Furthermore, in the cooling system 70 of the embodiment, when the control device 50 determines in the addition valve cooling request determination unit 50B that there is a need to cool the fuel addition valve 61 (addition valve) (step S020 in FIG. 3: YES), the electric pump control unit 50C determines the discharge flow rate and drive time (discharge flow rate and drive time for the fuel addition valve 61) of the electric pump 73 corresponding to the specified amount, and based on the determined discharge flow rate and drive time. Controls electric pump 73. Here, the electric pump control unit 50C does not need to calculate the discharge flow rate and drive time of the electric pump 73 corresponding to the specified amount (the discharge flow rate and drive time for the fuel addition valve 61). The electric pump 73 may be controlled based on the discharge flow rate and driving time for the addition valve 61.

In the cooling system 70 of the embodiment, the control device 50 controls the fuel addition valve 61 (addition valve) based on the kinematic viscosity of the coolant near the coolant inlet 74A of the fuel addition valve holder 74 in the electric pump control unit 50C. The driving time is corrected based on the kinematic viscosity (step S090 in FIG. 3), but the driving time does not have to be corrected based on the kinematic viscosity.

Further, in the cooling system 70 of the embodiment, the control device 50 calculates the driving time for the fuel addition valve 61 (addition valve) using the inflow coolant temperature and driving time characteristics stored in advance. It is not necessary to determine the driving time for the fuel addition valve 61 (addition valve) using the temperature/driving time characteristics. For example, the cooling system may be equipped with a coolant kinematic viscosity detection device that measures the kinematic viscosity of the coolant, and the cooling system may use the coolant kinematic viscosity detection device to measure the kinematic viscosity of the coolant and then determine the driving time. good.

Further, in the cooling system 70 of the embodiment, the control device 50 determines whether the fuel addition valve 61 (addition valve) needs to be cooled or not, and the intercooler 71 in the addition valve cooling request determination unit 50B and the intercooler cooling request determination unit 50E. If it is determined that cooling is necessary (step S110 in FIG. 3: YES), the electric pump control unit 50C controls the discharge flow rate and drive time of the electric pump 73 relative to the fuel addition valve 61 (addition valve). (step S090 in FIG. 3), the discharge flow rate and driving time of the electric pump 73 to the intercooler 71 (step S120 in FIG. 3) are determined, and the discharge on the side where the amount of coolant discharged from the electric pump 73 is increased is determined. The electric pump 73 is controlled based on the flow rate and driving time (steps S130 to S140 or step S070 in FIG. 3). The control device 50 is not limited to this, but the addition valve cooling request determining unit 50B and the intercooler cooling request determining unit 50E determine whether the fuel addition valve 61 (addition valve) needs to be cooled and the intercooler 71 needs to be cooled. If it is determined that both are present (step S110 in FIG. 3: YES), only the discharge flow rate and drive time of the electric pump 73 to the intercooler 71 are calculated, and only the discharge flow rate and drive time of the electric pump 73 to the intercooler 71 are calculated. The electric pump 73 may be controlled based on.

Furthermore, the cooling system 70 described in the above-described embodiments can be applied to internal combustion engines using various fuels for various uses, such as general vehicles, industrial vehicles, and power generation systems.

Furthermore, in the above description, when greater than or equal to (≧), less than or equal to (≦), greater than (>), less than (<), etc. are described, an equal sign may or may not be included.

1 Internal combustion engine system 10 Internal combustion engine 11A, 11B Intake pipe 11C Intake manifold 12A Exhaust manifold 12B, 12C, 12D, 12E Exhaust pipe 14A to 14D Injector 15 Internal combustion engine radiator 21 Intake flow rate detection device 21A Intake temperature detection device 22 Supercharger 22A Turbine 22B Compressor 23 Intake air temperature detection device 25 Accelerator depression amount detection device 27 Rotation detection device 28 Cylinder detection device 35 Differential pressure sensor 36A to 36D Exhaust temperature detection device 37A, 37B NOx detection device 41 First oxidation catalyst (DOC)
42 DPF (particulate matter collection filter)
43 SCR (selective reduction catalyst)
44 Second oxidation catalyst 50 Control device 50A Addition valve temperature detection section 50B Addition valve cooling request determination section 50C Electric pump control section 50D Inflow coolant temperature detection section 50E Intercooler cooling request determination section 61 Fuel addition valve 62 Urea water addition valve 70 Cooling System 71 Intercooler 72 Radiator for intercooler 73 Electric pump 74 Fuel addition valve holder (addition valve holder)
74A Coolant inlet 74B Coolant outlet 741 Inflow coolant temperature detection device 742 Outflow coolant temperature detection device 75 Coolant circulation passage 75A Cold coolant piping 75BA Upstream piping 75BB IC distribution piping 75BC FH distribution piping 75CA IC return piping 75CB FH return piping

Claims (5)

An intercooler provided in an intake path of an internal combustion engine having a supercharger that supercharges intake air;
an intercooler radiator that is separate from an internal combustion engine radiator that cools the internal combustion engine coolant that cools the internal combustion engine coolant that cools the intercooler;
an electric pump that circulates the coolant;
a control device that controls the electric pump;
A cooling system for an internal combustion engine, comprising:
The exhaust path of the internal combustion engine is provided with an additive valve that injects an additive into the exhaust gas to purify the exhaust gas,
The electric pump is capable of circulating the coolant and stopping circulation of the coolant between the intercooler radiator, the intercooler, and the addition valve,
The addition valve is housed in an addition valve holder,
The addition valve holder is filled with the circulated coolant,
The control device includes:
an addition valve temperature detection unit that estimates or measures an addition valve-related temperature that is a temperature related to the addition valve;
an addition valve cooling request determination unit that determines whether cooling of the addition valve is necessary based on the addition valve-related temperature;
an electric pump control section that controls the electric pump;
has
When the addition valve cooling request determination unit determines that there is a need to cool the addition valve, the electric pump control unit causes the electric pump to pump a specified amount of the coolant ;
The addition valve cooling request determination unit determines that there is a need to cool the addition valve when the addition valve related temperature exceeds a predetermined cooling start temperature,
The addition valve temperature detection unit estimates or measures the temperature of the coolant near the coolant outlet that is the coolant outlet in the addition valve holder as the addition valve related temperature;
When the addition valve cooling request determination unit determines that there is a need to cool the addition valve, the electric pump control unit determines the prescribed amount by which the entire amount of coolant in the addition valve holder can be replaced. forcing the electric pump to pump the coolant;
Internal combustion engine cooling system. A cooling system for an internal combustion engine according to claim 1 , comprising:
The control device includes:
If the addition valve cooling request determination unit determines that there is a need to cool the addition valve, the electric pump control unit determines the discharge flow rate and drive time of the electric pump corresponding to the specified amount; controlling the electric pump based on the determined discharge flow rate and the driving time;
Internal combustion engine cooling system. The internal combustion engine cooling system according to claim 2 ,
The control device includes:
The electric pump control unit corrects the driving time based on the kinematic viscosity of the coolant near a coolant inlet that is an inlet for the coolant in the addition valve holder.
Internal combustion engine cooling system. The internal combustion engine cooling system according to claim 3 ,
The control device includes:
an inflow coolant temperature detection unit that estimates or measures an inflow coolant temperature that is a temperature of the coolant near the coolant inlet in the addition valve holder;
The control device includes:
An inflow coolant temperature/drive time characteristic in which the drive time is set according to the inflow coolant temperature related to the kinematic viscosity of the coolant flowing in from the coolant inflow port is stored in association with the discharge flow rate,
The control device includes:
When the addition valve cooling request determination unit determines that there is a need to cool the addition valve, the electric pump control unit determines the discharge flow rate and combines the determined discharge flow rate with the inflow coolant temperature. , determining the driving time based on the inflow coolant temperature and driving time characteristics, and controlling the electric pump based on the determined discharge flow rate and the driving time;
Internal combustion engine cooling system. The cooling system according to any one of claims 2 to 4 ,
The control device includes:
an intercooler cooling request determination unit that determines whether cooling of the intercooler is necessary based on the operating state of the internal combustion engine;
In the addition valve cooling request determining section and the intercooler cooling request determining section,
If it is determined that there is no need to cool the addition valve and the intercooler, the electric pump control unit stops the operation of the electric pump,
If it is determined that there is no need to cool the addition valve and there is a need to cool the intercooler, the electric pump control unit determines the discharge flow rate and driving time of the electric pump to the intercooler; controlling the electric pump based on the determined discharge flow rate and the driving time;
If it is determined that there is a need to cool the addition valve and there is no need to cool the intercooler, the electric pump control unit determines the discharge flow rate and drive time of the electric pump with respect to the addition valve; controlling the electric pump based on the determined discharge flow rate and the driving time;
If it is determined that there is a need to cool both the addition valve and the intercooler, the electric pump control unit controls the discharge flow rate and drive time of the electric pump to the addition valve. and the discharge flow rate and drive time of the electric pump with respect to the intercooler, and calculate the discharge flow rate and drive time of the electric pump on the side where the amount of coolant discharged from the electric pump increases. control the pump,
Internal combustion engine cooling system.

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