JP4151406B2 - Cooling water circulation device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling water circulation device for an internal combustion engine that includes an engine-driven water pump and an electric water pump that are driven by the shaft output of the internal combustion engine.
[0002]
[Prior art]
In a vehicle equipped with a water-cooled engine (internal combustion engine) such as a gasoline engine or a diesel engine, a water pump that is driven by the shaft output of the engine, for example, driven by the rotation of the crankshaft by an endless belt, In addition to cooling the engine body by supplying cooling water to the engine, a part of the cooling water that exchanges heat with the engine body is led to the heater (air conditioning heater) of the vehicle air conditioner for heating in the passenger compartment. A cooling water circulation device is provided (see, for example, cited document 1).
[0003]
On the other hand, there is a vehicle with an idling stop function that stops engine operation during engine idling operation in order to suppress exhaust gas emission.
[0004]
However, since the water pump and the crankshaft of the engine are directly connected to each other, the vehicle with the idling stop function stops the water pump when the engine is stopped by the idle stop function. For this reason, if the vehicle is being heated, the cooling water is not supplied to the heater due to the stop of the engine operation, and heating using the exhaust heat of the engine cannot be performed.
[0005]
Therefore, in vehicles where engine shutdown control is temporarily performed during operation such as idling stop, in order to prevent a reduction in heating capacity, a heater introduction path for flowing cooling water from the engine body to the heater is separately provided. A technique has been proposed in which an electric water pump is provided to ensure heater performance during a period when the engine is stopped. This is a technique for operating an electric water pump instead of a water pump that stops when the engine is stopped due to, for example, idling stop during heating of the passenger compartment to continue heating by exhaust heat of the engine (for example, cited) Reference 1).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-179339
[Problems to be solved by the invention]
By the way, even with an engine having an idling stop function, it is required that warm-up is completed at an early stage in the warm-up operation as in the case of engines of other vehicles.
[0008]
However, at the time of cold start, the warmed cooling water inside the engine flows into the heater by the operation of the water pump that starts following the start of the engine. For this reason, the heat for warming up tends to escape from the heater and the warming up does not proceed effectively. Especially when the cooling water temperature is extremely low, it is easy to spend warm-up time. Such a problem can occur not only in a vehicle having an idle stop function but also in a hybrid vehicle in which an engine and a motor that require a temporary stop of engine operation are combined.
[0009]
Therefore, as a countermeasure, it is conceivable to provide a separate on-off valve such as a solenoid valve in the heater introduction path so as to prevent cooling water from flowing to the heater, but in addition to the electric water pump, A separate cost is required to install an on-off valve.
[0010]
Therefore, an object of the present invention is to provide a cooling water circulation device for an internal combustion engine that uses an existing electric water pump to promote engine warm-up operation.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a cooling system in which cooling water is circulated into the internal combustion engine by an engine driven water pump driven by the shaft output of the internal combustion engine to exchange heat with the internal combustion engine. A water distribution means, a heater introduction path for guiding a part of the cooling water heat-exchanged in the internal combustion engine to the air conditioning heater, the heater introduction path, and when the internal combustion engine is stopped, the air conditioning heater At the time of an operation request, instead of the engine-driven water pump, an electric water pump that allows cooling water to flow into the air conditioning heater; and during the warm-up operation of the internal combustion engine in which the cooling water is equal to or lower than a predetermined temperature value, as the cooling water flowing out from the internal combustion engine to the air-conditioning heater is suppressed, anda reverse rotation means for driving the electric water pump in the reverse direction, the reverse rotation means, said When the engine is equal to or greater than a predetermined rotational speed, it is configured to stop the operation of the electric water pump.
[0012]
With this configuration, during warm-up operation, the motor-driven water pump is operated in the reverse direction with respect to the cooling water supply flow toward the air conditioning heater, that is, the motor is discharged in the opposite direction by the reverse operation. The discharge flow from the water pump collides. As a result, the flow of cooling water from the internal combustion engine to the air conditioning heater is reduced or zero, and the warm-up heat is prevented from escaping from the air conditioning heater. In addition, since the electric water pump that reversely operates the existing electric water pump is utilized to suppress the outflow of the cooling water to the air conditioning heater, the cost is low.
[0013]
According to the second aspect of the present invention, in addition to the above-described object, the cooling water circulation means is provided with a radiator that, when exceeding a predetermined temperature, is supplied with cooling water that has been subjected to heat exchange in the internal combustion engine so as to perform warm-up more effectively. To the suction part of the engine-driven water pump, and when the temperature is lower than a predetermined temperature, the internal combustion engine is warmed using a structure having a plurality of systems that are bypassed and returned to the suction part of the engine-driven water pump without passing through the radiator. When operating the machine, the route that does not pass through the radiator was also used to improve the warm-up performance.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on an embodiment shown in FIGS. 1 and 3.
[0016]
FIG. 1 shows a cooling water circulating device for a water-cooled internal combustion engine, for example, a water-cooled engine 1 for traveling (hereinafter simply referred to as an engine 1) mounted on a vehicle having an idle stop function. The engine main body of the engine 1 is shown.
[0017]
Here, for example, the engine body 1 has a structure having, for example, three cylinders 3 a to 3 c arranged in series and surrounded by a water jacket 2. That is, for example, in each of the cylinders 3a to 3c, a piston (not shown) is reciprocally housed. Further, for example, an injector, a spark plug, an intake port with an intake valve, and an exhaust port with an exhaust valve (all not shown) are provided for each cylinder at the upper part of each cylinder 3a-3c. When the intake / exhaust operation, the fuel injection operation, and the ignition operation are performed at a predetermined timing, a predetermined combustion cycle such as intake, compression, explosion combustion, and exhaust is repeated in each of the cylinders 3a to 3c. It is.
[0018]
One of the front and rear end portions of the engine body 1 is formed with an inlet portion 4 a of a water channel formed by the water jacket 2. Moreover, the exit part 4b is similarly formed in the other. Of these, an engine-driven water pump 5 (hereinafter simply referred to as a water pump 5) driven by the crank output of the engine body 1 is attached to the inlet 4a. The water pump 5 has a structure directly connected to the engine 1, for example, a structure having an impeller (none of which is shown) that rotates by receiving a rotational force from the crankshaft of the engine body 1 through an endless belt. It is. The discharge part 5a of this water pump 5 is connected to the inlet part 4a of the water channel (water jacket 2). Thereby, when the impeller of the water pump 5 rotates, the cooling water flows in the engine body 1, that is, in the water jacket 2 (corresponding to the cooling water distribution means of the present application). In addition, a switching portion, for example, a thermostat 6 for switching the flow path according to the temperature of the cooling water is installed at the outlet portion 4b of the water channel (water jacket 2). For example, the thermostat 6 has a structure having two inlet portions 6a and 6b and one outlet portion 6c. Moreover, the thermostat 6 has a structure which operates a valve body with the wax which expands / contracts according to the temperature of the cooling water, for example, and when the cooling water exceeds a predetermined temperature (for example, about 50 ° C. to 80 ° C.) The inlet portion 6b and the outlet portion 6c are communicated with each other, and when the temperature is equal to or lower than the predetermined temperature, the inlet portion 6a and the outlet portion 6c are communicated with each other. And the inlet part 6a is connected to the outlet part 4b. The inlet 6b is connected to an end of a return path 7 for a radiator (hereinafter simply referred to as a return path 7) branched from an outlet side portion of a water channel formed by the water jacket 2, for example. A radiator 8 is provided in the middle of the return path 7. The outlet 6c is connected to the suction part 5b of the water pump 5 via a bypass return path 9 (hereinafter simply referred to as a return path 9). That is, when the cooling water exchanged with the engine 1 exceeds a predetermined temperature by the switching operation of the thermostat 6, the cooling water is returned to the water pump 5 through the radiator 8, and when the cooling water is lower than the predetermined temperature, it does not pass through the radiator 8. So that it can be returned to the water pump 5. That is, as shown by the one-dot chain line arrow A in FIG. 2, the cooling water is circulated in the bypass system bypassing the radiator 8 until the warm-up of the engine 1 is finished. As indicated by the solid line arrow B, the cooling water flows through two paths (return paths of a plurality of systems) that are circulated in the radiator system passing through the radiator 8.
[0019]
A heater introduction path 10 branches off from the outlet side portion of the water channel formed by the water jacket 2. A heater lead-out path 11 branches off from the flow path portion on the suction side of the water pump 5, for example, in the middle of the return path 9. The end portions of these introduction / exit paths 10 and 11 are an inlet portion 12a and an outlet portion of a heater 12 (which is composed of a heat exchanger and corresponds to the air conditioning heater of the present application) built in the vehicle air conditioner 16. It is connected to the part 12b. Thereby, a part of the heat-exchanged cooling water is introduced into the heater 12, that is, circulated by utilizing the operation of the water pump 5. The heater introduction path 10 is provided with an electric water pump 13. The electric water pump 13 has a structure in which, for example, an electric motor is directly connected to a pump portion (not shown) with a built-in impeller. Further, for example, when the electric motor operates in the forward rotation direction, cooling water from the engine 1 is discharged toward the heater 12 in the pump portion of the pump 13, and conversely from the heater 12 when the electric motor operates in the reverse rotation direction. A structure is used in which the discharge direction is switched by a change in the rotation direction of the impeller (forward / reverse rotation), in which cooling water is discharged toward the engine 1.
[0020]
On the other hand, 14 is an ECU (for example, constituted by a microcomputer). An electric water pump 13 is connected to the ECU 14. In addition to this, the ECU 14 detects, for example, a water temperature sensor 15 (a sensor for detecting the outlet water temperature of the engine 1) provided in the thermostat 6 of the engine 1 as various sensors for detecting the operating state of the engine 1, and the presence or absence of a brake. A brake sensor (not shown), a shift sensor (not shown) for detecting the shift position of the shift lever, and a vehicle speed sensor (not shown) for detecting the vehicle speed are connected. Further, the ECU 14 is connected with switches of an air conditioning operation panel for inputting an air conditioning signal, for example.
[0021]
Further, the ECU 14 has a function of stopping the operation of the engine 1 when the vehicle enters an idling operation, for example, when the vehicle speed is zero, the shift position is a neutral position, and the brake is turned on. A situation in which a traveling system is entered, for example, a shift position is a traveling position, for example, a D range position, and a function for starting the engine 1 when the brake is turned off are set. Further, the ECU 14 has an electric water pump 13 in place of the water pump 5 that stops in an air-conditioning state in which the operation of the heater 12 is required at the time when the idle stop is executed (when the operation of the heater 12 is requested), for example, during heating. The function to operate (forward rotation) is set. Thus, at the time of idling stop where heating is required, the cooling water warmed by the heat of the engine 1 flows through the heater 12 as shown by the arrow C shown by the broken line in FIG. I have to. That is, the electric water pump 13 operating instead of the water pump 5 ensures the heating capacity during the idle stop period when the engine 1 is stopped.
[0022]
In addition, the ECU 14 has a function for operating the electric water pump 13 in the reverse direction, that is, in the reverse operation during the warm-up operation in which the engine 1 is required to be warmed up, for example, when the engine 1 is started in the cold state. It is. For example, when it is detected from the ignition key signal that the engine is starting, and the coolant temperature sensor 15 detects that the cooling water temperature (engine outlet water temperature) is equal to or lower than a predetermined temperature value, for example, 50 ° C. or lower. A function of operating the motor of the water pump 13 in reverse rotation and a function of controlling the motor according to a preset pump discharge performance are used, for example. The pump discharge performance is provided with characteristics necessary for generating a discharge flow that opposes, for example, a cooling water supply flow toward the heater 13 (by the water pump 5). Thereby, at the time of cold start of the engine 1, the cooling water flowing into the heater 12 from the collision of the discharge flow from the electric water pump 13 and the supply flow from the water pump 5 until the cooling water exceeds 50 ° C. The flow of the is to be suppressed. Note that when the cooling water exceeds a predetermined temperature, for example, 50 ° C., the reverse operation of the electric water pump 13 is stopped. Further, the ECU 14 operates the electric water pump 13 when the rotational speed of the engine 1 exceeds a predetermined rotational speed during the warm-up operation, that is, an engine rotational speed that may cause a flow of cooling water that may cause cavitation. The function to stop is set.
[0023]
The warming-up performance of the engine 1 brought about by the reverse operation control of the electric water pump 13 will be described based on the flowchart shown in FIG. 3. Now, as shown in step S1, for example, the cooling water temperature is reduced to zero degrees Celsius or less. Assume that the engine 1 is started from the state by an ignition key operation. Then, the water pump 5 connected to the crankshaft of the engine 1 starts operation.
[0024]
Here, since the thermostat 6 has a cooling water temperature as low as 50 ° C. or lower, the thermostat 6 is switched to the bypass-side path according to the determination in step S2. Thus, until the cooling water temperature rises to a temperature at which the flow path of the thermostat 6 is switched, the cooling water of the engine 1 bypasses the radiator 8 as shown by the one-dot chain line arrow A in FIG. Circulates through a path that passes through the water pump 5, the water jacket 2 of the engine 1, the thermostat 5, and the return return path 9 for bypass. At this time, a part of the cooling water that has flowed inside the engine and is warmed by the heat of the engine 1 travels from the heater introduction path 11 to the heater 12.
[0025]
On the other hand, at this time, the cooling water temperature is not more than a predetermined temperature value, for example, 50 ° C. or less, and the rotational speed of the engine 1 is the threshold rotational speed without occurrence of cavitation, so that the electric water pump 13 is shown in Steps S2 and S3. Operates in reverse rotation as the engine 1 starts. Then, the electric water pump 13 starts the reverse operation, that is, the operation of discharging the cooling water to the heater introduction passage 10 in the reverse direction to the normal rotation. As a result, as shown in FIG. 2, the discharge flow (from the electric water pump 12) with respect to the cooling water supply flow (arrow C indicated by the broken line) provided by the water pump 5 on the heater introduction path 10 ( The arrows indicated by the two-dot chain line D) collide. At this time, since the electric water pump 12 controls the discharge performance, a discharge flow having a momentum suitable for canceling out the momentum of the supply flow is discharged. Therefore, the cooling from the engine 1 to the heater 12 is caused by the behavior of the collision. Water flow decreases (including stagnation). This warm-up operation continues until the cooling water temperature exceeds a predetermined temperature, for example, 50 ° C.
[0026]
Thus, during the warm-up operation, the electric water pump 5 used for idling stop can be utilized to prevent the warm-up heat from escaping from the heater 12 to the outside. Therefore, warm-up of the engine 1 can be promoted at a low cost.
[0027]
Moreover, if the engine 1 is warmed up by a path that bypasses the radiator 8, the cooling water flowing through the engine 1 is slowed down due to a decrease in the cooling water flowing out to the heater 12. Can warm up effectively.
[0028]
In addition, when the engine 1 exceeds a set rotation speed that is a threshold value for generating cavitation, the operation of the electric water pump 12 is stopped, so that the flow becomes faster (reduction of water flow resistance). Occurrence of cavitation can be avoided and damage to the engine 1 can be avoided. That is, when the cooling water flowing out to the heater 12 is reduced during the warm-up operation, the flow of the cooling water returning to the water pump 5 is delayed. For this reason, depending on the operating state of the engine 1 (for example, when the vehicle is running during warm-up), the flow of the engine-driven water pump 5 is accelerated, and the pre-water pump pressure may be reduced to cause cavitation. Therefore, when the rotational speed of the engine 1 causing a flow that may cause cavitation is exceeded, the operation of the electric water pump 12 is stopped by the determination in step S3, and the flow of the cooling water is delayed.
[0029]
The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in one embodiment, the present invention is applied to a vehicle with an idle stop function. However, the present invention is not limited to this, and a hybrid vehicle combining an engine and a motor that requires a temporary stop of engine operation or near an idle However, it may be configured to assist by operating the electric water pump when the heater flow rate cannot be ensured. In short, any structure may be used as long as the heater performance is ensured when the engine is stopped using the electric water pump.
[0030]
【The invention's effect】
As described above, according to the first aspect of the present invention, during the warm-up operation, the electric water pump is reversely operated, so that the cooling water supply flow from the engine-driven water pump toward the air conditioning heater is electrically driven. It is possible to reduce the cooling water from the internal combustion engine to the air conditioning heater by colliding the discharge flow from the water pump, and to prevent the warm-up heat from escaping from the air conditioning heater.
[0031]
Therefore, it is possible to promote engine warm-up. Moreover, in order to promote warm-up, an electric on-off water pump used to ensure the heater performance is used as it is instead of providing an on-off valve separately, so that the cost is low. In addition, it is possible to prevent the occurrence of cavitation due to a faster flow of cooling water (reduction of water flow resistance).
[0032]
According to the second aspect of the present invention, in addition to the above-described effect, when the cooling water flowing out to the air conditioning heater is reduced, the flow of the cooling water flowing through the internal combustion engine is slowed down. Warm-up can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a cooling water circulation device for an internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a view showing a flow of cooling water at the time of cold start in the apparatus.
FIG. 3 is a flowchart showing control of an electric water pump at the same cold start.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 5 ... Engine drive type water pump, 6 ... Thermostat, 7 ... Radiator return path, 8 ... Radiator, 9 ... Bypass return path, 10 ... Heater introduction path, 11 ... Heater derivation Road, 12 ... heater, 13 ... electric water pump, 14 ... ECU (reverse operation means), 15 ... water temperature sensor.

Claims (2)

Cooling water circulation means for circulating cooling water into the internal combustion engine by an engine-driven water pump driven by the shaft output of the internal combustion engine and exchanging heat with the internal combustion engine;
A heater introduction path for guiding a part of the cooling water heat-exchanged in the internal combustion engine to an air conditioning heater;
An electric water pump that is provided in the heater introduction path and that causes cooling water to flow into the air conditioning heater instead of the engine driven water pump when the internal combustion engine is stopped and the air conditioning heater is requested to operate; ,
The electric water pump is operated in the reverse direction so that the cooling water flowing out from the internal combustion engine to the air conditioning heater is suppressed during the warm-up operation of the internal combustion engine in which the cooling water becomes a predetermined temperature value or less. A reverse operation means ,
The cooling water circulating apparatus for an internal combustion engine, wherein the reverse operation means is configured to stop the operation of the electric water pump when the internal combustion engine reaches a predetermined rotational speed or more .   2. The cooling water circulation device for an internal combustion engine according to claim 1, wherein the cooling water circulation means supplies the cooling water heat-exchanged in the internal combustion engine to a suction portion of the engine-driven water pump through a radiator when the temperature exceeds a predetermined temperature. A cooling water circulation device for an internal combustion engine, comprising a plurality of systems for returning to a suction portion of the engine-driven water pump without passing through the radiator when the temperature is lower than a predetermined temperature. .

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