JP2002089265A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device for an internal combustion engine capable of controlling switch to supply of cooling water to a cylinder and a cylinder head based on a throttle opening or the like and thereby reduce knocking and improve fuel consumption. SOLUTION: The cooling device for the internal combustion engine capable of circulating the cooling water between the internal combustion engine and a radiator by driving a water pump is provided with an engine rotational frequency sensor 32 for detecting an engine rotational frequency of the internal combustion engine, a throttle sensor 33 for detecting an opening of a throttle valve, a switch valve 20 for optionally switching to supply the cooling water to the cylinder or the cylinder head of the internal combustion engine, a driving means 31 for driving the switch valve 20, and a control means 30 for controlling the driving means 31 based on the throttle opening θTh detected by the throttle sensor 33 and the engine rotational frequency Ne detected by the engine rotational frequency sensor 32. The control means 30 drives the driving means 31 to supply the cooling water to the cylinder head when it is determined that the throttle opening is large compared to the engine rotational frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled internal combustion engine.

[0002]

2. Description of the Related Art In general, in a water-cooled internal combustion engine, a water jacket on a cylinder block side and a water jacket on a cylinder head side communicate with each other, and cooling water discharged from a water pump flows from a cylinder to a cylinder head in order from a cylinder to a radiator. It has a structure that circulates and cools the engine.

[0003]

Therefore, it is not possible to supply water to each of the cylinder and the cylinder head in accordance with the engine speed and the operating load. Therefore, a delay in cooling the cylinder head may cause knocking, or the internal combustion engine may be cooled from the cylinder, resulting in a decrease in thermal efficiency and a decrease in fuel efficiency.

[0004] Japanese Patent Laid-Open No. 2000-73, in which cooling is controlled independently by piping to a cylinder and a cylinder head, respectively.
Although there is an example described in Japanese Patent Application Publication No. 770, this example is intended to suppress a decrease in temperature of residual gas in a combustion chamber by circulating a coolant that does not pass through a radiator only at a cylinder head at a low engine load. However, it is not intended to cool the cylinder head in the knocking occurrence region, and the effect of knocking reduction cannot be expected.

[0005] The present invention has been made in view of such a point,
An object of the present invention is to provide a cooling device for an internal combustion engine capable of controlling the switching supply of cooling water to a cylinder and a cylinder head based on a throttle opening and the like to reduce knocking and improve fuel efficiency. .

[0006]

In order to achieve the above object, according to the first aspect of the present invention, cooling water can be circulated between an internal combustion engine and a radiator by driving a water pump. In a cooling device for an internal combustion engine, an engine speed sensor for detecting an engine speed of the internal combustion engine, a throttle sensor for detecting an opening of a throttle valve, and selectively switching cooling water to a cylinder or a cylinder head of the internal combustion engine. A switching valve for supplying, a driving unit for driving the switching valve, and a control unit for controlling the driving unit based on a throttle opening detected by the throttle sensor and an engine speed detected by the engine speed sensor. The control means drives the drive means when it is determined that the throttle opening is larger than the engine speed, thereby controlling the cylinder head. The coolant was a cooling apparatus for an internal combustion engine to switch the switching valve to supply the.

When the throttle opening is larger than the engine speed, a rise in temperature due to acceleration is predicted, and the engine enters a region where knocking is likely to occur during transient operation. By supplying and cooling the combustion chamber, knocking can be effectively reduced.

Further, at this time, since the cooling water is not supplied to the cylinder side and is cooled from the cylinder side, fuel efficiency is not deteriorated due to a decrease in thermal efficiency, and fuel efficiency can be improved.

According to a second aspect of the present invention, in the cooling device for an internal combustion engine according to the first aspect, the control means may be arranged such that the detected throttle opening is larger than a predetermined throttle opening with respect to the engine speed by a predetermined width or more. When the determination is made, the switching valve is switched so that the driving means is driven to supply the cooling water to the cylinder head.

In order to determine that the throttle opening is larger than the engine speed, it is determined whether or not the detected throttle opening is larger than the steady throttle opening with respect to the engine speed by a predetermined width or more. Yes, when it is large, it is possible to preferentially supply cooling water to the cylinder head in advance to reduce knocking and improve fuel efficiency.

According to a third aspect of the present invention, in the cooling device for an internal combustion engine according to the first aspect, the control means compares the throttle opening degree and the engine speed with the engine speed in a coordinate system having both of the coordinate axes. A map in which a switching line for instructing the switching of the switching valve, which is a threshold line for determining that the opening is large, is provided in advance, and the relationship between the detected throttle opening and the engine speed is determined based on the map. And controlling the switching valve.

When it is determined that the throttle opening and the engine speed are greater than the engine speed beyond the switching line by referring to a map, the cooling water is preferentially supplied to the cylinder head. Knocking can be reduced and fuel efficiency can be improved.

According to a fourth aspect of the present invention, in the cooling apparatus for an internal combustion engine according to any one of the first to third aspects, the internal combustion engine is configured such that a cylinder and a cylinder head communicate a cooling water passage. The cylinder and the cylinder head each have a cooling water inlet, and the cylinder head has a cooling water outlet.

During steady running, the entire internal combustion engine is cooled by circulation from the cylinder to the cylinder head. However, during acceleration running in which the throttle opening is large compared to the engine speed, cooling water is preferentially supplied only to the cylinder head. It is possible to reduce knocking and improve fuel efficiency.

According to a fifth aspect of the present invention, in the cooling water device for an internal combustion engine according to the fourth aspect, the switching valve supplies cooling water discharged from a water pump to the cylinder and supplies the cooling water to the cylinder head. And recirculation without circulating the engine can be selectively switched.

By switching one switching valve, the entire engine is cooled by supplying cooling water to the cylinder during steady running.
By prioritizing the supply of cooling water to the cylinder head during accelerated driving, knocking is reduced and fuel efficiency is improved.
Early warm-up can be achieved by recirculation of the cooling water that does not circulate through the engine during cold / cold start. The number of parts can be reduced and the size of the switching valve body can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below with reference to FIGS. FIGS. 1 to 3 show a state of the cooling structure of the internal combustion engine 1 according to the present embodiment at the time of cold start, FIGS. 4 and 5 show a state at the time of steady running, and FIGS. And FIG.

The cooling structure will be described with reference to FIGS. Although the cylinder block 2 and the cylinder head 3 of the internal combustion engine 1 are shown separately, they are actually combined via a gasket, and a water jacket 2a around the cylinder bore of the cylinder block 2 is
The gasket hole communicates with the water jacket around the combustion chamber.

The cylinder block 2 has a cooling water inlet 2b communicating with the water jacket 2a, and the cylinder head 3 has a cooling water inlet 3a and a cooling water outlet 3b. FIG.
As shown in FIG. 3, a water pump 4 is provided on the cylinder head 3. A suction port 5a communicating with a pump suction port 4a and a discharge port 5b communicating with a pump discharge port 4b are provided on a pump cover member 5 covering the water pump 4. Is formed.

A suction pipe 6 communicating with the suction port 5a at the center thereof is projected from the pump cover member 5, and connection pipes 6a and 6b are fitted to both ends of the suction pipe 6. A pipe 12 having one end fitted to the one connection pipe 6a has the other end fitted to a cooling water outlet 10b of the radiator 10 to connect the radiator 10 and the water pump 4, and a cooling water inlet 10a of the radiator 10. Is connected to a cooling water outlet 3b of the cylinder head 3 by a pipe 11.

The switching valve used in the present embodiment
Reference numeral 20 denotes a rotary type four-way diverting valve, in which an inner rotor 22 is rotatably fitted in an outer stator 21. The outer stator 21 has four connecting pipes communicating with the inside protruding in a radial direction. The inner rotor 22, which is formed and rotates inside, constitutes a valve body.

The four connection pipes include a large-diameter inflow connection pipe I connected to the discharge port 5b of the water pump 4 by a large-diameter pipe 25, a cooling water inlet 3a of the cylinder head 3 and a large-diameter pipe 26. -Diameter outflow connection pipe Eh connected by
A small-diameter outflow connecting pipe Ec connected to the cooling water inlet 2b of the cylinder block 2 by a small-diameter pipe 27, and a large-diameter outflow connecting pipe connected to the suction port 5a of the water pump 4 by a large-diameter pipe 28. Ep.

The outflow connection pipe Eh is located at a position substantially opposite to the inflow connection pipe I, and the outflow connection pipe Ec and the outflow connection pipe Ep are connected to each other.
Are at right angles to the inflow connecting pipe I and at positions facing each other. The inner rotor 22, which is a valve body, is rotated by a servo motor 31 (or a step motor), and three outflow connection pipes Eh, from the internal space of the inner rotor 22 at a predetermined rotation angle.
The passage to Ec and Ep is opened and closed. The passage from the inflow connection pipe I to the inner space of the inner rotor 22 is
Is always open at the predetermined rotation angle.

FIG. 1 shows a state at the time of cold / cold start. The passages to the outflow connection pipes Eh and Ec are closed, and the outflow connection pipe E is closed.
Only the path to p is open. Therefore, the cooling water discharged from the discharge port 5b by driving the water pump 4
The pipe 28 flows into the inner space of the inner rotor 22 from the inflow connection pipe I of the switching valve 20 via the pipe 25, changes the flow at a right angle, and passes through the passage to the only outflow connection pipe Ep which is only opened.
And constitutes a circulation path for returning to the suction port 5a of the water pump 4 via the.

That is, the flow of the cooling water is schematically shown in FIG. 3, and as shown in FIG. 3, there is no circulation of the cooling water to the engine of the cylinder block 2, the cylinder head 3 and the radiator 10. The cooling water discharged from the water pump 4 is recirculated through the switching valve 20.

As described above, since the cooling water from the water pump 4 does not circulate in the engine, rapid warm-up can be performed at the time of cold start, thereby improving emission characteristics and initial stabilization of idling.

In this embodiment, the cooling water is not circulated to the radiator 10 at the time of the cold start.
May be connected to the cooling water inlet 10a of the radiator 10 to circulate the radiator 10, and the cooling water circulates through the radiator 10 at the start of cold and cold so that the temperature of the cooling water varies depending on the location. They can be kept the same.

Next, when the temperature of the cooling water rises to a certain extent, the switching valve 20 based on the temperature detected by the water temperature sensor 34 and the like.
(See FIG. 8), the inner rotor 22 rotates to a predetermined angular position to close the passage to the outflow connection pipe Ep and open the outflow connection pipes Eh and Ec as shown in FIG.

Therefore, the cooling water discharged from the water pump 4 flows into the inner space of the inner rotor 22 of the switching valve 20, and then changes its flow at right angles to the flow path flowing from the outflow connecting pipe Eh to the cylinder head 3 almost straight. The flow branches from the outflow connection pipe Ec to the flow path flowing to the cylinder block 2. This is a state during steady running.

The cooling water diverted to one of the outflow connection pipes Eh flows almost straight from the inflow connection pipe I, and the pipe 26 connected to the outflow connection pipe Eh and the cylinder head 3 has a large diameter. Flows to

On the other hand, the cooling water diverted to the outflow connection pipe Ec is
Since the flow is changed at right angles from the inflow connection pipe I and the pipe 27 connected to the outflow connection pipe Ec and the cylinder block 2 has a small diameter, there is resistance and flow is suppressed.

Therefore, a relatively large amount of cooling water flows through the cylinder head 3 and a small amount of cooling water flows through the cylinder block 2, so that the entire engine is cooled without excessive cooling of the engine and deterioration of fuel efficiency due to a decrease in thermal efficiency. can do.

The cooling water flowing into the cylinder block 2 is passed through the water jacket 2a to the cylinder head 3.
The cooling water flows into the radiator 10 via the pipe 11 from the cooling water outlet 3b together with the cooling water directly flowing into the cylinder head 3. Cooling water deprived of heat by radiator 10,
It returns to the suction port 5a of the water pump 4 via the pipe 12.

FIG. 5 is a simplified diagram showing the flow of the cooling water during the steady running. The circulation path of the water pump 4 → the switching valve 20 → the cylinder head 3 and the cylinder block 2 → the radiator 10 → the water pump 4 is formed, so that the entire internal combustion engine 1 can be efficiently cooled. Normally, the internal combustion engine is operated under such a cooling configuration, and steady traveling including gentle acceleration and deceleration is performed.

If the accelerator is suddenly greatly depressed during this steady running, the throttle valve is rapidly opened, the amount of air-fuel mixture sent to the combustion chamber is increased, the engine speed is increased, and a high load state is established. This is an operating area where knocking is likely to occur. During such acceleration traveling, the switching valve 20 is operated, and the inner rotor 22 rotates to a predetermined angular position to close the passage to the outflow connection pipe Ec and close the passage to the outflow connection pipe Ep as shown in FIG. Outflow connection pipe Eh
Only open state.

Accordingly, the cooling water discharged from the water pump 4 flows into the internal space of the inner rotor 22 of the switching valve 20, and then flows almost straight from the outflow connection pipe Eh to the cylinder head 3. Cooling water outlet 3b of cylinder head 3
The cooling water flows out of the radiator 10 through the pipe 11 and flows to the radiator 10, and the cooling water deprived of heat by the radiator 10
To the suction port 5a of the water pump 4 via

FIG. 7 is a simplified diagram showing the flow of the cooling water during the acceleration running. The circulation path of the water pump 4 → the switching valve 20 → the cylinder head 3 → the radiator 10 → the water pump 4 is formed, and all the cooling water flows to the cylinder head 3. Cools quickly

When the engine speed rises later due to the rapid opening of the throttle valve and a high load is predicted, the combustion chamber of the cylinder head 3 is cooled by a large amount of cooling water in advance, so that knocking occurs. Can be prevented.

The three states of cold start, cold start, steady running, and acceleration running are controlled by switching control of one switching valve 20, and a servo motor 31 for driving the switching valve 20 is controlled by an electronic control unit ECU30. FIG. 8 shows a schematic block diagram of the control system.

The ECU 30 receives detection signals from an engine speed sensor 32 for detecting the engine speed of the internal combustion engine 1, a throttle sensor 33 for detecting the opening of the throttle valve, a water temperature sensor 34 for detecting the temperature of the cooling water, and the like. Entered,
The drive signal is output to the servo motor 31 that drives the switching valve 20 after the signal processing.

As described above, the transition from the cold start state to the steady running state is performed when the water temperature detected by the water temperature sensor 34 exceeds the predetermined water temperature, a predetermined drive signal is output to the servo motor 31 and the inner rotor of the switching valve 20 is turned on. 22 is turned to the turning position shown in FIG.

The transition between the steady running state and the accelerated running state is performed by making a decision based on the engine speed and the throttle opening and controlling the switching valve 20. FIG. 9 shows the relationship between the engine speed Ne and the throttle opening θTh in XY rectangular coordinates, where the engine speed Ne is on the X axis and the throttle opening θTh is on the Y axis.

The constant throttle opening change for the engine rotational speed Ne denotes the constant throttle opening change curve C ₀ of substantially constant gradient as indicated by a broken line. If, however, such as throttle opening θTh is suddenly opened, as indicated by a solid line deviates from the steady-state throttle opening change curve C ₀ large throttle opening as compared to the engine speed above (Y-axis positive direction) 9 shows an acceleration throttle opening change curve C.

The ECU 30 stores the steady-state throttle opening change curve C ₀ together with the XY rectangular coordinates in a memory, and stores the throttle opening θ detected by the throttle sensor 33.
The difference Δθ from the steady throttle opening at the engine speed Ne detected simultaneously with Th is calculated.

[0045] When this [Delta] [theta] is greater than the predetermined width [Delta] [theta] ₁ that has been determined in advance, a predetermined drive signal from the ECU30 to predict high load is outputted to the servo motor 31, the inner rotor 22 of the switching valve 20 in FIG. 6 In this state, the cooling water is preferentially flown to the cylinder head 3 prior to the high load state to rapidly cool the combustion chamber to prevent knocking.

After that, the engine speed follows and rises,
The detected throttle opening θTh approaches the steady throttle opening change curve C ₀ , and Δθ is a predetermined width Δθ ₂
When it becomes smaller, the inner rotor 22 of the switching valve 20
Is returned to the rotation position shown in FIG.

The predetermined width Δθ ₁ is set to a value at which it is assumed that when the difference from the steady throttle opening becomes larger than this value, the throttle opening becomes larger than the engine speed and enters the knocking occurrence region. The predetermined width Δθ _{2 is} also set to a value that is assumed to be out of the knocking occurrence area when the difference from the steady throttle opening is smaller than this value.

As described above, when the detected throttle opening is larger than the predetermined width Δθ _{1 by} more than the steady throttle opening with respect to the engine engine speed Ne, the cylinder head 3
The cooling water can be supplied preferentially to reduce knocking. Further, since no cooling water is supplied to the cylinder block 2, deterioration of fuel efficiency due to a decrease in thermal efficiency can be prevented, and fuel efficiency can be improved.

[0049] to control switching of the switching valve 20 as described above, in addition to the method of assuming a constant throttle opening change curve C _0, have a map for previously engine speed and the throttle opening, detect Engine speed Ne
And the throttle opening θTh may be determined by referring to a map.

FIG. 10 shows an example of the map. The relationship between the engine speed Ne and the throttle opening θTh is shown in XY rectangular coordinates, where the engine speed Ne is on the X axis and the throttle opening θTh is on the Y axis. The line Lh for switching to the cylinder head shown in the map is a predetermined line where the throttle opening is larger than the engine speed and is assumed to be in the knocking occurrence region.

The region on the left side of the line Lh where the throttle opening is larger than the engine speed is the knocking occurrence region, and the point on the map indicated by the detected engine speed Ne and the throttle opening θTh is the same region. Enter the EC
A predetermined drive signal is output from U30 to the servo motor 31,
The inner rotor 22 of the switching valve 20 is turned to the turning position shown in FIG. 6, and prior to the high load state, the cooling water is preferentially flown to the cylinder head 3 to rapidly cool the combustion chamber to prevent knocking. Can be prevented.

The cylinder switching line Lc shown in the map is a predetermined line which is assumed to go out of the knocking occurrence area, and is a map showing the detected engine speed Ne and the throttle opening θTh. When the upper point enters the area on the right side of the line Lc, the inner rotor 22 of the switching valve 20 is returned to the rotation position shown in FIG.

As described above, by switching one rotary switching valve 20, the entire engine is cooled by supplying cooling water to the cylinder block 2 during steady running, and the cooling water cylinder head is preceded during accelerated running. Thus, knocking can be reduced and fuel efficiency can be improved by preferential supply to the engine 3, and early warm-up can be achieved by recirculation of the cooling water without circulating the engine during cold / cold start. It is not necessary to separately provide a thermostat or another valve in addition to the switching valve 20, so that the number of parts can be reduced and the switching valve body can be downsized as a rotary switching valve.

FIGS. 11 to 1 show modifications of the switching valve.
4 and will be described. Referring to FIG. 11, the internal combustion engine and the cooling structure other than the switching valve 50 are the same as those of the above-described embodiment, and the same reference numerals are used.

The switching valve 50 is a rotary four-way diverting valve similar to the switching valve 20, and has an inner stator 52 rotatably fitted in an outer stator 51. As shown in FIGS. 11 and 12, the outer stator 51 has three connecting pipes communicating with the inside thereof formed so as to protrude in the rotation radiation direction of the inner rotor 52, and the remaining one is connected to the inner rotor 52.
52 are formed in the direction of the rotation axis.

The connecting pipe projecting in the rotational radial direction of the inner rotor 52 is a large-diameter inflow connecting pipe I connected to the discharge port 5b of the water pump 4 by the large-diameter pipe 25.
And a cooling water inlet 3a of the cylinder head 3 and a large-diameter pipe
26, and a small-diameter outflow connection pipe Ec connected to the cooling water inlet 2b of the cylinder block 2 and the small-diameter pipe 27 in the direction of the rotation axis of the inner rotor 52. The protruding connection pipe is a large-diameter outflow connection pipe Ep connected to the suction port 5a of the water pump 4 by a large-diameter pipe 28.

The outflow connection pipe Eh is at a position facing the inflow connection pipe I, and the outflow connection pipe Ec and the outflow connection pipe Ep are at right angles to the inflow connection pipe I and at right angles to each other.
FIG. 11 shows a state at the time of cold start, and the outflow connection pipe E is shown.
h, the passage to Ec is closed, only the passage to the outflow connection pipe Ep is opened, and the cooling water discharged from the water pump 4 flows from the inflow connection pipe I of the switching valve 50 through the pipe 25 to the inside of the inner rotor 52. The water flows into the space, changes the flow at a right angle, and forms a circulation path that returns to the suction port 5a of the water pump 4 through the pipe 28 through the passage to the outlet connection pipe Ep that is only opened.

Since the cooling water from the water pump 4 does not circulate in the engine, rapid warm-up can be performed at the time of cold start, so that emission characteristics can be improved and idling can be initially stabilized.

Next, when the cooling water temperature rises to some extent,
The switching valve 20 is operated, and the inner rotor 52 rotates to a predetermined angular position to close the passage to the outflow connection pipe Ep and open the outflow connection pipes Eh and Ec as shown in FIG.

The cooling water discharged from the water pump 4
After flowing into the inner space of the inner rotor 22 of the switching valve 20, the flow is changed straight at right angles to the flow path flowing from the outflow connection pipe Eh to the cylinder head 3 and divided into the flow path flowing from the outflow connection pipe Ec to the cylinder block 2. Then, the vehicle is in a state of steady running.

Therefore, a relatively large amount of cooling water flows through the cylinder head 3 and a small amount of cooling water flows through the cylinder block 2 in the same manner as in the above-described embodiment. While cooling the entire engine.

At the time of acceleration traveling, the switching valve 52 turns the inner rotor 52 further by a predetermined angle to the state shown in FIG. 14, closing the passage to the outflow connection pipe Ec, and setting the outflow connection pipe Ec.
The passage to p remains closed and only the outflow connection pipe Eh is open.

When the engine speed rises later due to the rapid opening of the throttle valve and a high load is predicted, the combustion chamber of the cylinder head 3 is cooled by a large amount of cooling water in advance, so that knocking occurs. Can be prevented.

Although the switching valve is a rotary flow dividing valve in the above, a sliding flow dividing valve is also conceivable, and FIGS. 15 to 17 show an example thereof. This slide type switching valve 60
A slide valve 62 is slidably fitted inside a cylindrical outer case 61, and the slide valve 62 is slid by a step motor 65 via a wire 66.

The slide valve 62 is biased by a spring or the like, and the step motor 65 has a structure in which the slide valve 62 is pulled in the opposite direction via a wire 66. Outer case 61
The openings at both ends are connected to the discharge ports of the water pump, cooling water flows in from both ends, and outlets Eh, Ec, Ep are opened at three predetermined positions on the peripheral wall of the outer case 61. The outlet Eh is connected to the cylinder head, the small-diameter outlet Ec is connected to the cylinder block, and the large-diameter outlet Ep is connected to the water pump, respectively, to form the same cooling water circulation path as in the above embodiment.

The slide valve 62 has an inflow hole I passing through the center axis thereof, and annular grooves 63 and 64 are formed at two predetermined positions on the outer peripheral surface. A communication hole extends from the inflow hole 62a toward the annular grooves 63 and 64. 63
a and 64a penetrate respectively.

FIG. 15 shows a state at the time of cold / cold start. The slide valve 62 closes the outlets Eh and Ec, and the outlet E
p is opened in accordance with the annular groove 64, and the inflow holes 62
The cooling water from the water pump that has flowed into
a, Reflux from the outlet Ep through the annular groove 64 to the water pump.

When the temperature of the cooling water rises to some extent, the switching valve 60 is operated, the slide valve 62 slides to a predetermined position, closes the outlet Ep as shown in FIG.
Open c together.

Therefore, a relatively large amount of cooling water flows from the large-diameter outlet Eh to the cylinder head, and the small-diameter outlet Ec
A relatively small amount of cooling water flows from the cylinder block to the cylinder block, and the vehicle is in a state of steady running.

At the time of acceleration traveling, the slide valve 62 is further slid a predetermined distance, and as shown in FIG.
By closing c and Ep and opening only the outlet Eh, the combustion chamber of the cylinder head 3 is cooled by a large amount of cooling water, and the occurrence of knocking can be prevented.

FIG. 18 shows another example of the switching valve.
In this switching valve 70, three outflow passages Ep, Eh, and Ec are branched from the inflow passage I of the cooling water.
Solenoid valves 71, 72, 73 are arranged at h and Ec, respectively.

The large-diameter outflow passage Eh is connected to the cylinder head, the small-diameter outflow passage Ec is connected to the cylinder block, and the large-diameter outflow passage Ep is connected to the water pump, respectively. A road is constructed.

The ECU controls each of the solenoid valves 71, 72, 73. During cold start, only the outflow passage Ep is opened, so that the cooling water can be warmed up quickly without circulating through the engine. The passage Ep is closed, the large-diameter outflow passage Eh and the small-diameter outflow passage Ec are opened, and the entire engine can be cooled while mainly cooling the cylinder head to prevent a decrease in fuel efficiency due to a decrease in thermal efficiency. Only the outflow passage Eh is opened to cool the combustion chamber of the cylinder head 3 with a large amount of cooling water to prevent knocking.

The control for switching the switching valve to the state at the time of acceleration traveling is based on the judgment based on the engine speed and the throttle opening detected by the throttle sensor.
In order to detect the rapid opening of the throttle valve, the rate of change of the throttle opening, that is, the angular velocity of the rotation of the throttle valve or the angular acceleration which is the rate of change may be calculated and the determination may be made based on this.

That is, a predetermined angular velocity or a predetermined angular acceleration at which a high load state of the throttle valve is predicted is determined in advance, and the angular velocity or the angular acceleration of the throttle valve calculated from the throttle opening detected by the actual throttle sensor is determined in advance. When it is determined that the angular velocity or the angular acceleration exceeds a predetermined value, the switching valve is switched to a state at the time of acceleration traveling.

Next, another embodiment of a cooling structure will be described with reference to FIGS. In the cooling structure, the switching valve 20 is located on the upstream side of the cylinder block 2 and the cylinder head 3, and the water jacket of the cylinder block 2 and the cylinder head 3 is in communication. It is located downstream of the block 81 and the cylinder head 82, and the water jacket of the cylinder block 81 and the cylinder head 82 is not in communication.

In the switching valve 85, the inflow connection pipe Ic is connected to the water jacket of the cylinder block 81, the inflow connection pipe Ih is connected to the water jacket of the cylinder head 82, and the outflow connection pipe Er is connected to the radiator 84. The inflow connection pipe Ih and the outflow connection pipe Er are always in communication, and the communication of the inflow connection pipe Ic is controlled by an on-off valve. That is, the switching valve 85 corresponds to a merging valve.

The water pump 83 sucks in the cooling water from the radiator 84, and the discharged cooling water can be supplied to the cylinder block 81 and the cylinder head 82 with the communication path branched in the middle.
FIG. 19 shows a state during steady running. When the inflow connection pipe Ic is opened as shown in FIG. 19, the cooling water circulating through the radiator 84 is cooled by the cylinder block 81 and the cylinder head.
82 simultaneously flows, and the entire internal combustion engine can be efficiently cooled.

At the time of acceleration running in which the accelerator is suddenly greatly depressed during steady running, the inflow connection pipe Ic of the switching valve 85 is closed, and the flow of the cooling water to the cylinder block 81 is stopped as shown in FIG. All the cooling water flows to the cylinder head 82, and a large amount of cooling water
The 82 combustion chambers are quickly cooled, and the occurrence of knocking can be prevented.

Next, another embodiment will be described with reference to FIGS. 21 and 22 which are simplified diagrams. In this cooling structure, the water jackets of the cylinder block 81 and the cylinder head 82 communicate with each other, and switching valves are provided on the upstream and downstream sides of the cylinder block 81 and the cylinder head 82, respectively.
95 and a switching valve 96 are provided.

FIG. 21 shows a state during steady running.
The water pump 93 draws in the cooling water from the radiator 94 and discharges it to the switching valve 95, and the switching valve 95 is connected to the cylinder block 91.
And cooling head to cylinder head 92 at the same time
The cooling water 96 flows from both the cylinder block 91 and the cylinder head 92 and returns to the radiator 94. Therefore, the entire internal combustion engine can be efficiently cooled.

At the time of acceleration running, as shown in FIG. 22, the switching valve 95 closes the outflow connection pipe Ec to the cylinder block 91, the switching valve 96 closes the inflow connection pipe Ic from the cylinder block 91, and the water pump 93 discharges. All the cooling water thus supplied flows to the cylinder head 92, and the combustion chamber of the cylinder head 92 is rapidly cooled by a large amount of the cooling water, so that occurrence of knocking can be prevented.

The cylinder block 81 and the cylinder head
Since the water jacket 82 is in communication, the switching valve 95 closes the outflow connection pipe Eh to the cylinder head 92 and opens the outflow connection pipe Ec to the cylinder block 91 as shown in FIG. By closing the inflow connection pipe Ic from the cylinder head 91 and opening the inflow connection pipe Ih from the cylinder head 92, a state during steady running different from that in FIG. 21 can be configured.

That is, as shown in FIG. 23, the cooling water discharged from the water pump 93 flows from the cylinder block 91 to the cylinder head 92, and forms a flow from the cylinder head 92 to the radiator 94 via the switching valve 96. The entire internal combustion engine can be cooled.

The servo motor for driving the switching valve in each of the above embodiments of the present invention is configured as a stepping motor so as to open and close each cooling water passage of the switching valve in a stepwise manner. 7, the temperature rise of the stagnation portion of the cooling water in each part by allowing a small amount of the cooling water to flow without completely closing the closed passage of the cooling water passage in each of FIGS. 20, 22, and 23. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state of a cooling structure of an internal combustion engine at a cold start.

FIG. 2 is a sectional view of a water pump.

FIG. 3 is a simplified diagram showing a flow of cooling water of the cooling structure.

FIG. 4 is a cross-sectional view showing a state during steady running in the cooling structure of the internal combustion engine.

FIG. 5 is a simplified diagram showing a flow of cooling water of the cooling structure.

FIG. 6 is a cross-sectional view showing a state during acceleration running in the cooling structure of the internal combustion engine.

FIG. 7 is a simplified diagram showing a flow of cooling water of the cooling structure.

FIG. 8 is a schematic block diagram of a cooling control system.

FIG. 9 is a graph showing a change in the throttle opening with respect to the engine speed.

FIG. 10 is a map for determining switching of a switching valve based on an engine speed and a throttle opening.

FIG. 11 is a cross-sectional view showing a state at the time of cold start in a cooling structure of an internal combustion engine using another switching valve.

12 is a cross-sectional view of the switching valve taken along line XII-XII of FIG.

FIG. 13 is a cross-sectional view showing a state of the switching valve during steady running.

FIG. 14 is a cross-sectional view showing a state of the switching valve during acceleration traveling.

FIG. 15 is a cross-sectional view showing a state of another slide type switching valve at the time of cold start.

FIG. 16 is a cross-sectional view showing a state of the switching valve during steady running.

FIG. 17 is a cross-sectional view showing a state of the switching valve during acceleration traveling.

FIG. 18 is a sectional view of a switching valve using still another solenoid valve.

FIG. 19 is a simplified diagram showing a flow of cooling water during steady running of a cooling structure according to another embodiment.

FIG. 20 is a simplified diagram showing a flow of cooling water during acceleration traveling of the cooling structure.

FIG. 21 is a simplified diagram showing the flow of cooling water during steady running of a cooling structure according to still another embodiment.

FIG. 22 is a simplified diagram showing a flow of cooling water during acceleration running of the cooling structure.

FIG. 23 is a simplified diagram showing a flow of cooling water during another steady running in the cooling structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder block, 3 ... Cylinder head, 4 ... Water pump, 5 ... Pump cover member, 6
... Suction pipe, 10 ... Radiator, 11,12 ... Pipe, 20 ... Switching valve, 21 ... Outer stator, 22 ... Inner rotor, 25,2
6, 27, 28 ... pipe, 30 ... ECU, 31 ... servo motor, 3
2… Engine rotation sensor, 33… Throttle sensor, 3
4 water temperature sensor, 50 switching valve, 51 outer stator, 52 inner rotor, 60 switching valve, 61 outer case, 62 slide valve, 63, 64 annular groove, 65 step motor, 66 wire 70 ... Switching valve, 71, 72, 73 ... Solenoid valve, 81 ... Cylinder block, 82 ... Cylinder head, 83 ... Water pump, 84 ... Radiator, 85 ... Switching valve, 91 ... Cylinder block, 92 ... Cylinder head, 93 ... Water Pump, 94
... radiators, 95, 96 ... switching valves.

Claims (5)

[Claims] An internal combustion engine cooling device capable of circulating cooling water between an internal combustion engine and a radiator by driving a water pump, an engine speed sensor for detecting an engine speed of the internal combustion engine, a throttle valve A throttle sensor for detecting an opening of the engine, a switching valve for selectively switching cooling water to a cylinder or a cylinder head of the internal combustion engine, a driving unit for driving the switching valve, and a throttle opening detected by the throttle sensor. Control means for controlling the driving means based on the engine speed and the engine speed detected by the engine speed sensor, when the control means determines that the throttle opening is larger than the engine speed. Wherein the switching valve is switched so as to supply the cooling water to the cylinder head by driving the driving means. Cooling system. 2. The control means drives the drive means to supply cooling water to the cylinder head when it determines that the detected throttle opening is larger than a predetermined width than the steady throttle opening with respect to the engine speed. The cooling device for an internal combustion engine according to claim 1, wherein the switching valve is switched so as to supply the cooling gas. 3. The control means instructs the switching of the switching valve, which is a threshold line for judging that the throttle opening is larger than the engine speed in coordinates using the throttle opening and the engine speed as both coordinate axes. 2. A map in which a switching line to be set is set in advance, and the switching valve is controlled by judging a detected throttle opening and an engine speed from a relationship with the switching line by referring to the map. A cooling device for an internal combustion engine according to claim 1. 4. The internal combustion engine according to claim 1, wherein the cylinder and the cylinder head communicate a cooling water passage, the cylinder and the cylinder head each have a cooling water inlet, and the cylinder head has a cooling water outlet. The cooling device for an internal combustion engine according to any one of claims 1 to 3. 5. The switching valve can selectively switch between supply of the cooling water discharged from a water pump to the cylinder, supply to the cylinder head, and recirculation without circulating the engine. The cooling water device for an internal combustion engine according to claim 4.