JP2019065804A - Temperature retaining control device for internal combustion engine - Google Patents

Abstract

To provide a temperature retaining control device for an internal combustion engine which can suitably retain temperature of the internal combustion engine.SOLUTION: When a thermostat is closed (step S1; YES) and a heat quantity of an internal combustion engine is less than a prescribed heat quantity (step S2; YES), an ECU temporarily stops driving of an electric water pump for prescribed time (step S3). When the thermostat is closed and the heat quantity of the internal combustion engine determined on the basis of a fuel injection amount is less than the prescribed heat quantity, the ECU temporarily stops driving of the electric water pump for the prescribed time. When the thermostat is closed and an integrated value of the heat quantity of the internal combustion engine in a previous prescribed time period is less than the prescribed heat quantity, the ECU temporarily stops driving of the electric water pump for the prescribed time. The thermostat is a thermosensitive type thermostat which opens and closes in accordance with a temperature of cooling water.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a heat retention control device for an internal combustion engine.

  In the conventional internal combustion engine, cooling water is circulated between the internal combustion engine and the radiator to maintain the temperature of the internal combustion engine at an appropriate temperature. What was described in patent document 1 as this kind of technique is known. According to Patent Document 1, when the temperature of the cooling medium satisfies the rapid heating condition, the operation of the electric pump is controlled to increase the flow rate of the cooling medium flowing into the thermostat.

  In the case of Patent Document 1, when the temperature change per unit time of the cooling medium becomes equal to or higher than the set increase rate, or the temperature of the cooling medium becomes equal to or higher than the set temperature, and the cooling medium It is determined that the rapid heating condition is established when the temperature change per unit time becomes equal to or higher than the set increase rate.

JP 2008-240686 A

  Here, the control of the circulation amount of the cooling water is performed not only to prevent the internal combustion engine from being overheated but also to keep the internal combustion engine from being overcooled. If the heat retention of the internal combustion engine is not properly performed, problems such as deterioration of fuel efficiency due to an increase in cooling loss due to supercooling may occur.

  However, since the thing of patent document 1 is not considering keeping warm so that the temperature of an internal combustion engine does not fall below suitable temperature, there existed a possibility that an internal combustion engine might be overcooled. Moreover, since the thing of patent document 1 is controlling the action | operation of an electrically driven pump based on the temperature change of a cooling water (cooling medium), there existed a possibility that a delay might generate | occur | produce in control. That is, the control amount of the electric pump can not be changed until the temperature change of the cooling water is actually detected at the installation position of the temperature sensor or the like. For this reason, there has been a risk that the internal combustion engine may be overcooled due to a delay in control in the case of Patent Document 1.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a heat retention control device for an internal combustion engine that can keep the internal combustion engine appropriate.

  In order to achieve the above object, the present invention provides a radiator for radiating heat of cooling water, an electric water pump for circulating cooling water between the radiator and an internal combustion engine, and a radiator and the internal combustion engine A heat retention control device for an internal combustion engine, comprising: a thermostat for adjusting the flow rate of circulating cooling water; and a control unit for controlling the electric water pump, the control unit closing the thermostat, And, when the calorific value of the internal combustion engine is less than a predetermined calorific value, driving of the electric water pump is temporarily stopped for a predetermined time.

  According to the present invention, the temperature of the internal combustion engine can be properly maintained.

FIG. 1 is a configuration diagram showing a state of a heat retention control device for an internal combustion engine according to an embodiment of the present invention when a thermostat is closed. FIG. 2 is a configuration diagram showing a state of the heat retention control device for an internal combustion engine according to one embodiment of the present invention when the thermostat is open. FIG. 3 is a flow chart for explaining the heat retention control operation of the internal combustion engine by the heat retention control device for an internal combustion engine according to one embodiment of the present invention. FIG. 4 is a flowchart for explaining the details of step S2 of FIG.

  A heat retention control device for an internal combustion engine according to an embodiment of the present invention comprises a radiator for radiating heat of the cooling water, an electric water pump for circulating the cooling water between the radiator and the internal combustion engine, a radiator and the internal combustion engine A thermostat for controlling the flow rate of cooling water circulating between the control unit and a control unit for controlling the electric water pump, the control unit closing the thermostat, And when the calorific value of the internal combustion engine is less than a predetermined calorific value, driving of the electric water pump is temporarily stopped for a predetermined time. Thus, the heat retention control device for an internal combustion engine according to one embodiment of the present invention can properly keep the internal combustion engine warm.

  Hereinafter, a heat retention control device for an internal combustion engine according to an embodiment of the present invention will be described using the drawings.

  In FIG. 1, a vehicle 10 equipped with a heat retention control device for an internal combustion engine according to an embodiment of the present invention is configured to include an internal combustion engine 4 and an ECU (Electronic Control Unit) 5 as a control unit.

  The internal combustion engine 4 is constituted by a four-stroke engine which performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke while the piston reciprocates two cylinders.

  The internal combustion engine 4 is provided with a water jacket and a water gallery (not shown) through which cooling water flows. The radiator 3 is connected to the internal combustion engine 4 via a feed side cooling water pipe 9A and a return side cooling water pipe 9B. The cooling water circulates through the internal combustion engine 4 and the radiator 3. The radiator 3 dissipates the heat of the cooling water.

  The feed side cooling water pipe 9A is connected to the cooling water outlet 4A of the internal combustion engine 4 and the radiator 3 and introduces the high temperature cooling water passing through the inside of the internal combustion engine 4 from the cooling water outlet 4A. And sent to the radiator 3.

  The return side cooling water pipe 9B is connected to the cooling water inlet 4B of the internal combustion engine 4, and returns the cooled cooling water that has passed through the inside of the radiator 3 to the cooling water inlet 4B.

  The electric water pump 2 is provided in the internal combustion engine 4, and the electric water pump 2 pumps coolant from the cooling water inlet 4 B of the internal combustion engine 4 toward the cooling water outlet 4 A. The electric water pump 2 circulates the coolant between the radiator 3 and the internal combustion engine 4 when the thermostat 1 described later is opened. The electric water pump 2 is electrically connected to the ECU 5 and is controlled by the ECU 5.

  A thermostat 1 is provided at the cooling water outlet 4A. The thermostat 1 is a thermal thermostat that opens and closes in accordance with the temperature of the cooling water, and adjusts the flow rate (flow rate) of the cooling water circulating between the radiator 3 and the internal combustion engine 4. The thermostat 1 is designed to open by expansion of the wax enclosed therein due to heat.

  The internal combustion engine 4 is provided with a turbocharger and an intercooler 6 which are not shown. The turbocharger utilizes the exhaust gas discharged from the internal combustion engine 4 to compress the intake air. The intercooler 6 cools the intake air which has been heated when compressed by the turbocharger. The intercooler 6 is connected to the internal combustion engine 4 via a feed side bypass pipe 6A through which cooling water flows and a return side bypass pipe 6B. The feed side bypass pipe 6A is connected to the internal combustion engine 4 so as to bypass the thermostat 1. The return side bypass pipe 6B is connected to the return side cooling water pipe 9B.

  The internal combustion engine 4 is provided with a heater core 7, and the heater core 7 uses the heat of the internal combustion engine 4 to create warm air for heating. The heater core 7 is connected to the internal combustion engine 4 via a feed side bypass piping 7A and a return side bypass piping 7B through which cooling water flows. The feed side bypass pipe 7A is connected to the cooling water outlet 4A so as to bypass the thermostat 1. The return side bypass pipe 7B is connected to the return side cooling water pipe 9B.

  An AT oil cooler 8 is provided in the internal combustion engine 4, and the AT oil cooler 8 cools the oil of an automatic transmission (AT) not shown. The AT oil cooler 8 is connected to the internal combustion engine 4 via a feed side bypass pipe 8A and a return side bypass pipe 8B through which cooling water flows. The feed side bypass pipe 8A is connected to the cooling water outlet 4A so as to bypass the thermostat 1. The return side bypass pipe 8B is connected to the return side cooling water pipe 9B.

  In such an internal combustion engine 4, when the temperature of the cooling water is less than the valve opening temperature of the thermostat 1, the thermostat 1 is closed. Thereby, the cooling water circulates between the internal combustion engine 4 and the intercooler 6, between the internal combustion engine 4 and the heater core 7, and between the internal combustion engine 4 and the AT oil cooler 8, as shown in FIG. On the other hand, when the temperature of the cooling water is equal to or higher than the valve opening temperature of the thermostat 1, the thermostat 1 is opened. Thereby, the cooling water further circulates between the internal combustion engine 4 and the radiator 3 as shown in FIG.

  The ECU 5 is configured to include a microcomputer provided with a CPU, a RAM, a ROM, an input / output interface and the like, and electrically controls the operating state of the internal combustion engine 4 and the operating state of the electric water pump 2 .

  The CPU uses the temporary storage function of the RAM and performs signal processing in accordance with a program stored in advance in the ROM. Various control constants, various maps, and the like are stored in advance in the ROM.

  Here, if the temperature of the internal combustion engine 4 falls below the appropriate range, the cooling loss will increase and the fuel consumption will also deteriorate, so it is required to properly control the electric water pump 2 and keep the internal combustion engine 4 warm properly. . Further, since the temperature of the cooling water changes behind the change of the calorific value of the internal combustion engine 4, if the electric water pump 2 is temporarily controlled based on only the temperature change of the cooling water, the delay is affected and the internal combustion engine It is not possible to keep the engine 4 properly warm.

  Therefore, in the present embodiment, when the thermostat 1 is closed and the calorific value of the internal combustion engine 4 is less than the predetermined calorific value, the ECU 5 stops the driving of the electric water pump 2. Further, the ECU 5 is configured to determine the calorific value of the internal combustion engine 4 based on the fuel injection amount.

  Further, the ECU 5 uses the integrated value of the heat generation amount of the internal combustion engine 4 in the predetermined period immediately before as the heat generation amount of the internal combustion engine 4. The predetermined period immediately before is a period from the past time to the present time by a predetermined time. The ECU 5 may use the calorific value per unit time, that is, the instantaneous value of the calorific value, instead of the integral value of the calorific value. Further, when the driving of the electric water pump 2 is stopped, the ECU 3 temporarily stops the driving of the electric water pump 2 for a predetermined time.

  Next, with reference to FIG. 3, a heat retention control operation performed by the ECU 5 in the heat retention control device for an internal combustion engine according to the present embodiment will be described. This heat retention control operation is a heat retention operation so that the temperature of the internal combustion engine 4 at an appropriate temperature does not decrease.

  In FIG. 3, the ECU 5 determines whether the water temperature of the cooling water is less than the valve opening temperature of the thermostat 1 (shown as a thermo valve in the drawing) (step S1). Here, the ECU 5 determines that the thermostat 1 is closed based on the water temperature of the cooling water.

  If the water temperature is less than the valve opening temperature in step S1, the ECU 5 determines whether the calorific value of the internal combustion engine 4 is less than the predetermined calorific value A (step S2).

  If the heat generation amount is less than the predetermined heat generation amount A in step S2, the ECU 5 temporarily stops driving of the electric water pump 2 for a predetermined time (step S3), and ends the current operation.

  The ECU 5 drives the electric water pump 2 according to the calorific value of the internal combustion engine 4 when the water temperature is the valve opening temperature or more in step S1 or when the calorific value is more than the predetermined calorific value A in step S2 (step S4) , End this operation. In step S4, the ECU 5 increases the drive amount of the electric water pump 2, that is, the discharge amount of the cooling water, as the heat generation amount of the internal combustion engine 4 increases.

  Here, the process of step S2 is performed by determining the calorific value based on the presence or absence of the fuel injection to the internal combustion engine 4.

  Specifically, as shown in FIG. 4, the ECU 5 determines whether or not fuel injection is in progress (step S11), and if fuel injection is in progress, the heat value per unit time is integrated over the predetermined period immediately before integration. It is determined whether the value is less than the predetermined heat generation amount A (step S12).

  If the integrated value of the heat generation amount is less than the predetermined heat generation amount A in step S12, the ECU 5 determines that the heat generation amount is less than the predetermined heat generation amount in step S13, and ends the current operation. On the other hand, if the fuel injection is not in progress in step S11, or if the integrated value of the heat generation amount is equal to or more than the predetermined heat generation amount A in step S12, the current operation is ended without executing step S13.

  As described above, in the present embodiment, when the thermostat 1 is closed and the calorific value of the internal combustion engine 4 is less than the predetermined calorific value, the ECU 5 stops the driving of the electric water pump 2.

  Thereby, when the thermostat 1 is closed and the calorific value of the internal combustion engine 4 is less than the predetermined calorific value, the driving of the electric water pump 2 is stopped to establish the thermal equilibrium state in the internal combustion engine 4 be able to. That is, since the heat energy of the internal combustion engine 4 can be prevented from being taken through the cooling water, it is possible to establish a thermal equilibrium state in which the heat quantity generated by the internal combustion engine 4 and the heat quantity taken from the internal combustion engine 4 are equal.

  In addition to this, since the driving of the electric water pump 2 is stopped while the thermostat 1 is in the closed state, the low temperature cooling water accumulated in the radiator 3 when the electric water pump 2 is driven again It is possible to prevent the internal combustion engine 4 from being overcooled because it is rapidly introduced into the internal combustion engine 4. As a result, the internal combustion engine 4 can be properly kept warm.

  In addition to this, since the cooling water can be suppressed from being cooled by stopping the electric water pump 2 in the present embodiment, it is possible to suppress the cooling capacity from flowing through the heater core and lowering the heating capacity.

  Further, in the present embodiment, when the thermostat 1 is closed and the calorific value of the internal combustion engine 4 determined based on the fuel injection amount is less than the predetermined calorific value, the ECU 5 drives the electric water pump 2. Temporarily stops for a predetermined time.

  Thus, when the fuel injection is stopped and the internal combustion engine 4 does not generate heat, the amount of heat generation of the internal combustion engine 4 becomes less than the predetermined amount of heat generation, and the driving of the electric water pump 2 is stopped. Therefore, the heat energy of the internal combustion engine 4 can be prevented from being taken away via the cooling water, so that the internal combustion engine 4 can be kept warm properly. Further, the driving of the electric water pump 2 is temporarily stopped for a predetermined time, and during the temporarily stopped predetermined time, regardless of the comparison result of the calorific value and the predetermined calorific value in the next control cycle. Since the driving of the electric water pump 2 is stopped, the internal combustion engine 4 can be reliably kept warm.

  Further, in this embodiment, the ECU 5 drives the electric water pump 2 when the thermostat 1 is closed and the integrated value of the heat generation amount of the internal combustion engine 4 in the predetermined period immediately before is less than the predetermined heat generation amount. Temporarily stops for a predetermined time.

  Thus, the driving of the electric water pump 2 can be controlled based on the heat generation amount integrated value representing the delay of heat transfer from the internal combustion engine 4 to the cooling water, so the electric water pump 2 is stopped to keep the internal combustion engine 4 warm. In this case, it is possible to prevent the cooling water from boiling locally at a high temperature part such as a cylinder head of the internal combustion engine 4.

  Further, in the present embodiment, the thermostat 1 is a thermal thermostat that opens and closes in accordance with the temperature of the cooling water.

  Thus, by stopping the driving of the electric water pump 2 in a state where the thermostat 1 is closed, the cooling water in the internal combustion engine 4 can hardly reach the thermostat 1, and the closed state of the thermostat 1 can be maintained. it can. Therefore, the heat retention effect of the internal combustion engine 4 by stopping the driving of the electric water pump 2 can be sufficiently obtained.

  As mentioned above, while an embodiment of the present invention has been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 thermostat 2 electric water pump 3 radiator 4 internal combustion engine 5 ECU (control unit)

Claims (4)

A radiator that dissipates the heat of the cooling water,
An electric water pump for circulating cooling water between the radiator and an internal combustion engine;
A thermostat for adjusting a flow rate of cooling water circulating between the radiator and the internal combustion engine;
And a control unit configured to control the electric water pump.
The control unit
A heat retention control device for an internal combustion engine, wherein driving of the electric water pump is temporarily stopped for a predetermined time when the thermostat is closed and the calorific value of the internal combustion engine is less than a predetermined calorific value. . The control unit
When the thermostat is closed and the calorific value of the internal combustion engine determined based on the fuel injection amount is less than a predetermined calorific value, the driving of the electric water pump is temporarily stopped for a predetermined time. The heat retention control device for an internal combustion engine according to claim 1. The control unit
When the thermostat is closed and the integrated value of the heat generation amount of the internal combustion engine in a predetermined period immediately before is less than the predetermined heat generation amount, the driving of the electric water pump is temporarily stopped for a predetermined time. The heat retention control device for an internal combustion engine according to claim 1 or 2.   The heat retention control device for an internal combustion engine according to any one of claims 1 to 3, wherein the thermostat is a thermal thermostat that opens and closes according to the temperature of the cooling water.

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