JPH05179948A - Cooling device for engine - Google Patents

Abstract

PURPOSE:To adjust the temperature of cooling water circulating in a water jacket according to the load condition of an engine. CONSTITUTION:When an engine main body 1 is started, a control unit 34 reads the intake air quantity signal Qa output from an air flow meter 3 and the engine speed signal Na output from a crank angle sensor 6 and computes an initial basic injection quantity Tpa. A basic injection quantity Tp and engine speed N are obtained from this. Based on the basic injection quantity Tp and the engine speed N, set water temperature is read out from a Tp-N map previously memorized in a memory area 34A, and a control signal according to deviation between the set water temperature and the water temperature Ta output from a water temperature sensor 13 is applied on a flow control valve 21. Hereby, the valve opening of the flow control valve 21 is changed, the flow of cooling water flowing from a water jacket to a radiator 9 through a charge/ discharge piping 8 is adjusted, and hence the temperature of cooling water is controlled to be the set water temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device suitable for cooling an automobile engine, for example.

[0002]

2. Description of the Related Art FIG. 12 shows an automobile engine cooling device as an example of a conventional engine cooling device.

In the figure, 1 is, for example, four cylinders 1.
Shown is an engine body composed of A, 1A, ... And a crank shaft 1B, and a water jacket (not shown) in which cooling water circulates is formed in a cylinder block constituting each cylinder 1A. A water pump 10 and a fan 11, which will be described later, are provided on the other end side of the engine body 1. And the engine body 1
Is to burn a mixture of fuel and intake air sucked from an intake manifold 2 described later in each cylinder 1A, and derive a rotational output by this combustion from the crankshaft 1B.

Reference numeral 2 denotes an intake manifold connected to the intake side of the engine body 1. The downstream side of the intake manifold 2 branches to communicate with each cylinder 1A of the engine body 1, and the upstream side thereof will be described later. An air flow meter 3, a throttle valve 4, etc. are provided. Further, the intake manifold 2 is provided with a fuel injection valve (not shown).

Reference numeral 3 denotes an air flow meter which is provided on the downstream side of an air cleaner (not shown) and is provided in the middle of the intake manifold 2 and is connected to a control unit 14 which will be described later. The amount of intake air sucked into 2 is detected, and this intake air amount is output to the control unit 14 as an intake air amount signal Qa.

A throttle valve 4 is provided on the downstream side of the air flow meter 3 in the middle of the intake manifold 2, and a throttle valve 5 for controlling the intake air amount according to the opening is provided in association with the throttle valve 4. 2 shows a throttle sensor, and the throttle sensor 5 is a control unit 1
4 is connected. The throttle sensor 5 detects the valve opening of the throttle valve 4 and outputs it as a valve opening signal θa to the control unit 14.

Reference numeral 6 denotes a crank angle sensor attached to the crankshaft 1B of the engine body 1, and the crank angle sensor 6 detects the engine speed and outputs it to the control unit 14 as an engine speed signal Na. It has become. Reference numeral 7 denotes a pressure sensor provided on the downstream side of the intake manifold 2. The pressure sensor 7 detects an intake negative pressure in the intake manifold 2 and outputs the intake negative pressure signal Pa.
Is output to the control unit 14.

Reference numeral 8 denotes an engine body 1 and a radiator 9 which will be described later.
And a radiator 9 and a flow control valve 12 to be described later, together with a supply / discharge pipe that constitutes an engine cooling device. One end of the supply / discharge pipe 8 communicates with an inlet (not shown) of a water jacket. Then, the other end side communicates with the water supply pipe 8A connected to the outflow port 9B of the radiator 9, the one end side communicates with the outflow port (not shown) of the water jacket, and the other end side is the drainage connected to the inflow port 9A of the radiator 9. It is composed of a pipe 8B and a bypass pipe 8C which is provided in communication between the water supply pipe 8A and the drain pipe 8B and serves as a throttle passage, and a flow control valve 12 is provided in the middle of the drain pipe 8B. ing. The supply / discharge pipe 8 supplies the cooling water flowing out from the outlet 9B of the radiator 9 into the water jacket via the water supply pipe 8A, and the cooling water discharged from the water jacket via the drain pipe 8B. It is designed to be returned to the radiator 9.

Reference numeral 9 denotes a radiator which is located on the front side of the vehicle and is provided on the other end side of the supply / discharge pipe 8. The radiator 9
The drain pipe 8B of the supply / discharge pipe 8 is connected to the inflow port 9A of
The water supply pipe 8A of the water supply / discharge pipe 8 is connected to the outflow port 9B. Then, the radiator 9 is the drain pipe 8 of the supply / discharge pipe 8.
While cooling the high temperature cooling water flowing from B, the supply / discharge pipe 8
It is designed to flow into the water supply pipe 8A.

Reference numeral 10 denotes a water pump located on the other end side of the engine body 1 and provided in the middle of the supply / discharge pipe 8.
The water pump 10 is driven by the rotation output of the engine body 1 and forcibly circulates the cooling water. 1
Reference numeral 1 denotes a fan that is provided on the other end side of the engine body 1 and is driven to rotate by the rotation output of the engine body 1 together with the water pump 10. The fan 11 blows air to the radiator 9 to enhance cooling efficiency of the radiator 9. It is like this.

Reference numeral 12 denotes a flow rate control valve, which is located on the radiator 9 side of the bypass pipe 8C of the supply / discharge pipe 8 and is provided in the middle of the drain pipe 8B and includes a wax pellet valve or the like.
The flow rate control valve 12 controls the flow rate of the cooling water flowing between the water jacket and the radiator by sensing the temperature of the cooling water flowing in the drain pipe 8B and adjusting the valve opening. is there. Here, the flow control valve 12 is
For example, when the temperature of the cooling water flowing through the drainage pipe 8B is higher than 80 ° C., the cooling water discharged from the water jacket is allowed to flow into the radiator 9 in a fully opened state, and the temperature of the cooling water is kept at a predetermined level. When the temperature is lower than the temperature, the cooling water drained from the water jacket is completely returned to the inside of the water jacket through the bypass pipe 8C to prevent the engine body 1 from being overcooled.

Reference numeral 13 denotes a water temperature sensor mounted on the engine body 1 at the outlet side of the water jacket. The water temperature sensor 13 detects the temperature of the cooling water flowing through the outlet side of the water jacket. This water temperature is output to the control unit 14 as a water temperature signal Ta.

Reference numeral 14 denotes a control unit composed of a CPU and the like as a microcomputer, and a storage area 14 is provided in a storage circuit of the control unit 14.
A is provided. Also, the control unit 1
An air flow meter 3, a throttle sensor 5, a crank angle sensor 6, a pressure sensor 7, and a water temperature sensor 13 are connected to the input side of 4, and a fuel injection valve is connected to the output side. The control unit 14 then receives the intake air amount signal Qa output from the air flow meter 3 and the engine speed signal Na output from the crank angle sensor 6.
The basic injection amount is calculated from the above, various correction coefficients are calculated for this basic injection amount, and the fuel injection signal is output to the fuel injection valve.

Reference numeral 15 denotes an exhaust manifold connected to the exhaust side of the engine body 1, and the exhaust manifold 15
Is for exhausting exhaust gas discharged from each cylinder 1A of the engine body 1.

The engine cooling device according to the prior art has the above-described structure. When the temperature of the engine body 1 is low, the flow control valve 12 is fully closed and the cooling water drained from the water jacket is bypassed. It recirculates into the water jacket through 8C, and prevents each cylinder 1A of the engine body 1 from being supercooled and lowering the combustion efficiency. Further, when the temperature of the engine body 1 rises, the flow rate control valve 12 is fully opened, the high temperature cooling water flowing out from the water jacket is circulated toward the radiator 9, and the cooling water cooled by the radiator 9 is circulated. It is circulated in the water jacket to prevent overheating of each cylinder 1A, and the water temperature on the outlet side of the water jacket is maintained at about 80 ° C.

[0016]

By the way, according to the above-mentioned conventional technique, the flow control valve 12 is provided in the middle of the drain pipe 8B of the supply / discharge pipe 8, and the supply / discharge pipe 8 is circulated by the flow control valve 12. Although the flow rate of the cooling water is controlled and the temperature of the cooling water circulating in the water jacket is maintained at about 80 ° C., the flow rate control valve 12 is composed of a wax pellet valve, so that the temperature responsiveness is improved. There is a problem in that the reproducibility of the valve opening (valve lift amount) is low, and the temperature of the cooling water circulating in the water jacket cannot be accurately maintained at, for example, about 80 ° C.

Further, in recent years, the market demands for the engine to have contradictory performances such as "high output and low fuel consumption". In order to realize "high output", the cooling water temperature in the water jacket must be lowered. Therefore, the cooling efficiency of each cylinder 1A must be increased, and on the other hand, in order to achieve "low fuel consumption", it is necessary to raise the temperature of the cooling water to improve the combustion efficiency in each cylinder 1A. .. However, the flow control valve 1
2 controls the flow rate of the cooling water flowing through the radiator 9 only on the basis of the temperature of the cooling water flowing through the drainage pipe 8B of the supply / discharge pipe 8. Therefore, during high-power running and fuel-efficient running There is a problem that the temperature of the cooling water cannot be controlled according to the load state of the engine body 1 at the time.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides an engine cooling device capable of adjusting the temperature of the cooling water circulating in the water jacket according to the load state of the engine. To do.

[0019]

The features of the configuration adopted by the present invention to solve the above-mentioned problems are that they are provided in the middle of the supply and discharge pipes, and a control signal from the outside causes a gap between the water jacket and the radiator. A flow rate control valve for controlling the flow rate of the circulating cooling water, a water temperature setting means for calculating the set water temperature of the cooling water based on the load state of the engine body, and the flow rate control based on the set water temperature calculated by the water temperature setting means The water temperature control means for outputting a control signal to the valve and controlling the temperature of the cooling water to the set water temperature is provided.

Further, it is preferable that the water temperature setting means detects the load state of the engine body from the basic injection amount and the engine speed.

Further, the water temperature setting means may detect the load state of the engine body from the valve opening of the throttle valve and the water temperature of the cooling water.

Furthermore, the water temperature setting means may detect the load condition of the engine body from the suction negative pressure and the water temperature of the cooling water.

[0023]

With the above structure, the water temperature setting means calculates and obtains the set water temperature of the cooling water based on the load state of the engine body, and the water temperature control means outputs a control signal to the flow control valve based on the set water temperature. Then, the flow rate control valve controls the flow rate of the cooling water flowing between the radiator and the water jacket by this control signal to adjust the temperature of the cooling water to the set water temperature.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIG. 12 described above are designated by the same reference numerals, and the description thereof will be omitted.

1 to 7 show the first embodiment of the present invention.

In the figure, reference numeral 21 denotes a displacement amplification type flow control valve according to the present embodiment, which is located on the radiator 9 side of the bypass pipe 8C of the supply / discharge pipe 8 and provided in the middle of the water distribution pipe 8B. Reference numeral 22 denotes a casing of the flow rate control valve 21 attached to the drainage pipe 8B. Inside the casing 22, a laminated piezoelectric body 25, a piston 23, etc., which will be described later, are housed.
A piston insertion hole 22A is formed on the lower surface side of the casing 22, a piston 23 is slidably provided in the piston insertion hole 22A, and oil is sealed inside the casing 22 by the piston 23. There is.

Reference numeral 24 denotes a stepped plate-like support plate fixed to the inside of the casing 22 so as to cover the opening side (piston insertion hole 22A side) of the casing 22, and the outer peripheral side of the support plate 24. A plurality of oil holes 24A, 24A, ... (Only two are shown) are bored in the axial direction (vertical direction), and a laminated piezoelectric body 25 is attached to the upper surface side.

Reference numeral 25 denotes a laminated piezoelectric body fixed to the upper surface side of the support plate 23. The laminated piezoelectric body 25 is composed of a plurality of piezoelectric bodies 25.
, And electrodes 25B, 25B, ... Arranged between the respective piezoelectric bodies 25A, and each of the electrodes 25B.
Is connected via a lead wire 26 to a control unit 3 described later.
4 is connected. Then, when the duty signal D described later is applied from the control unit 34, the laminated piezoelectric body 25 expands in the direction of the arrow U in FIG. 2 to pressurize the oil in the upper oil chamber 32 described later to increase the pressure. This pressure is increased and is applied to the upper surface side of the piston 23 through the oil hole 24A of the support plate 24 to move the piston 23 in the direction of arrow D.

Reference numeral 27 denotes a spring bearing fixed to the lower end side of the piston 23, 28 denotes a valve body provided downward at the center of the spring bearing 27, and a partition wall portion 29 described later is provided at the tip end side of the valve body 28. A poppet-like valve portion 28A that moves up and down in the circulation port 29A is provided. Then, when the laminated piezoelectric body 25 expands and contracts in the U and D directions shown by the arrows, the valve body 28 is provided with the piston 2
3 moves up and down in the drainage pipe 8B to allow the valve portion 28A to enter the flow opening 29A of the partition wall portion 29 to adjust the flow passage area.

29 is integrally formed on the inner wall of the drain pipe 8B,
A partition part provided with a flow port 29A, 30 is the partition part 29
2 shows a valve spring formed of a coil spring provided between the valve spring 28 and the spring receiver 27, and the valve spring 30 always biases the valve body 28 in the valve opening direction.

Reference numeral 31 is an oil passage provided between the inner periphery of the casing 22 and the outer periphery of the laminated piezoelectric body 25, and 32 is a large passage formed between the inner surface of the lid of the casing 22 and the upper surface of the laminated piezoelectric body 25. The upper diameter oil chambers 33 and 33 are the lower diameter oil chambers formed on the lower surface side of the support plate 24 and formed in the piston insertion holes 22A, respectively. The passages 31 communicate with each other. Then, the oil in the upper oil chamber 32, which is pressurized by the displacement of the laminated piezoelectric body 25 slightly, passes through the oil passage 31 and the lower oil chamber 33.
Is introduced into the cylinder and presses the piston 23 so as to make a large displacement.

Reference numeral 34 represents a control unit according to the present embodiment which is configured as a microcomputer from a CPU or the like. The control unit 34 is similar to the control unit 14 described in the prior art, and the air flow meter 3 and the throttle are provided on the input side. Although the sensor 5, the crank angle sensor 6, the pressure sensor 7, and the water temperature sensor 13 are connected, a flow rate control valve 21 is connected to the output side of the control unit 34 together with a fuel injection valve (not shown). The storage area 34A stores the programs shown in FIGS. 3 and 5 and the Tp-N map shown in FIG.

The engine cooling device according to the present embodiment has the above-mentioned structure. Next, the water temperature setting process will be described with reference to FIGS. 3 and 4.

First, in step 1, when the engine body 1 is started, the starting set water temperature Tm stored in advance in the storage area 34A is set in the set water temperature Tst, and in step 2, the set number of times Nst is set to a predetermined constant. In the next step 3, the count flag Con indicating how many times the data has been measured, the engine speed N and the basic injection amount Tp obtained in step 9 described later are initialized.

Then, in step 4, the intake air amount signal Qa output from the air flow meter 3 and the engine speed signal Na output from the crank angle sensor 6 are read. In the next step 5, the initial basic injection amount Tpa is calculated from the intake air amount signal Qa and the engine speed signal Na.

[0036]

## EQU1 ## Tpa = k.multidot. (Qa / Na) where k is a constant.

Then, in step 6, the engine speed signal Na and the initial basic injection amount Tp obtained in step 5 above.
and a are added to the engine speed N and the basic injection amount Tp initialized in the step 3, respectively, and the following step 7
Then, 1 is added to the rotation flag Con to store the number of measurements, and in step 8, the number of times flag Con is set to the set number Ns.
It is determined whether or not t has been reached. In this step 8, "N
When it is determined to be “O”, the count flag Con is set to the set count N.
Since it has not reached st, the procedure returns to step 4, and if "YES" is determined in this step 8, the intake air amount signal Qa and the engine speed signal Na are read for the set number of times Nst and the engine speed N is set. Basic injection amount Tp
Since it has been added to each of the above, the process proceeds to the next step 9.

Then, in step 9, step 6
The engine speed N and the basic injection amount Tp integrated in step S1 are divided by a set number of times Nst to obtain an average value, and in the next step 10, based on the averaged engine speed N and the basic injection amount Tp. , The set water temperature Tst is read from the Tp-N map shown in FIG. 4, and the water temperature control process shown in FIG.

Next, the water temperature control process will be described with reference to FIGS.

First, in step 11, the water temperature sensor 13
The water temperature signal Ta output from is read, and in step 12, the set water temperature Ts obtained in step 10 shown in FIG. 3 is read.
t is compared with this water temperature signal Ta to obtain the temperature difference ΔT,
In step 13, the proportional duty amount Dp is obtained from the proportional value map shown in FIG. 6 based on this temperature difference ΔT, and in step 14, the temperature difference ΔT obtained in step 12 is obtained from the integral value map shown in FIG. Based on this, the duty change amount Di is obtained.

Then, in step 15, the proportional duty amount Dp obtained in step 13 and the step 14
The duty signal D as a control signal is calculated from the duty change amount Di obtained in

[0042]

## EQU2 ## Obtained as D = Dp + Di.

Since the duty signal D is composed of the proportional duty amount Dp and the duty change amount Di as shown in the above equation 2, the value of the duty signal D depends on the change amount of the duty change amount Di. Are gradually changing.

Then, in the next step 16, a voltage pulse corresponding to the duty signal D is applied to the laminated piezoelectric body 25, and the laminated piezoelectric body 25 is slightly expanded and contracted in the U and D directions indicated by the arrow to cause the inside of the upper oil chamber 32. Change the pressure of. This allows
The change in pressure of the upper oil chamber 32 is transmitted to the lower oil chamber 33, and the piston 23 is pressed by the pressure amplified according to the cross-sectional area ratio of the oil chambers 32, 33. It moves up and down with a large displacement together with 28. The flow passage area of the flow port 29A of the partition wall portion 29 is equal to the valve portion 2 of the valve body 28.
8A, the flow rate of the cooling water flowing through the water distribution pipe 8B of the water supply / discharge pipe 8 toward the radiator 9 is gradually controlled in accordance with the duty change amount Di, and then, through the connector B, as shown in FIG. Returning to step 3 shown above.

Thus, according to this embodiment, the set water temperature Tst can be set based on the averaged basic injection amount Tp and the engine speed N, and the set water temperature Tst is set.
By applying a duty signal D corresponding to the flow rate to the laminated piezoelectric body 25, the valve body 28 allows the flow port 29 of the partition wall 29 to flow.
Since the flow area of A can be adjusted and the flow rate of the cooling water flowing through the drain pipe 8B of the supply / discharge pipe 8 toward the radiator 9 can be controlled, the inside of the water jacket can be adjusted according to the load state of the engine body 1. The temperature of the circulating cooling water can be variably controlled, the engine output and the fuel consumption can be obtained according to the load state of the engine body 1, and the engine body 1 can be efficiently cooled to significantly improve the engine performance. be able to.

Next, FIGS. 8 and 9 show a second embodiment of the present invention. The feature of this embodiment is that the set water temperature is determined based on the valve opening of the throttle valve and the water temperature of the cooling water. There is something I did. In this embodiment, the same components as those in the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals and the description thereof will be omitted.

First, in step 21, the engine body 1
When is started, the starting set water temperature Tm stored in advance in the storage area 34A of the control unit 34 is set in the set water temperature Tst, and in step 22, the set number of times Ns is set.
A predetermined constant is set to t, and in the next step 23, the number of times flag Con and the valve opening θ and the water temperature T obtained in step 28 described later are initialized.

Then, in step 24, the valve opening signal θa output from the throttle sensor 5 and the water temperature signal Ta output from the water temperature sensor 13 are read, and in step 25, the valve opening signal read in step 24 is read. The degree signal θa and the water temperature signal Ta are added to the valve opening degree θ and the water temperature T initialized in step 23, respectively, and in the next step 26, 1 is added to the number of times flag Con to store the number of measurements, and step 27 Then, it is determined whether or not the count flag Con has reached the set count Nst. This step 27
When it is determined to be “NO” in step 27, it means that the number-of-times flag Con has not reached the set number of times Nst. Therefore, the processing returns to step 24. Ta is set number of times Ns
Since only t has been read and the valve opening θ and the water temperature T have been added up, the process proceeds to the next step 28.

Then, in step 28, the valve opening θ and the water temperature T integrated in step 25 are each divided by the set number of times Nst to obtain an average value, and next step 29
Then, based on the averaged valve opening degree θ and the water temperature T, the set water temperature Tst is read from the θ-T map shown in FIG. 9, and the water temperature control process shown in FIG. Here, the θ-T map is a plurality of cooling water temperatures T
The relationship between 1, T2, T3, ... (T1>T2> T3) and the valve opening θ is stored as a map. Then, the θ-T
The map shows that when the cooling water temperature T is constant, the set water temperature Tst decreases as the valve opening θ increases.
It is in inverse proportion.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same operational effects as those of the first embodiment.

Next, FIGS. 10 and 11 show a third embodiment of the present invention.
The embodiment is characterized in that the set water temperature is obtained based on the suction negative pressure of the intake manifold and the water temperature of the cooling water. In the present embodiment, the same components as those in the first embodiment shown in FIGS. 1 to 7 are designated by the same reference numerals and the description thereof will be omitted.

First, in step 31, the engine body 1
When is started, the starting set water temperature Tm stored in the storage area 34A of the control unit 34 in advance is set to the set water temperature Tst, and in step 32, the set number of times Ns is set.
A predetermined constant is set to t, and in the next step 33, the number of times flag Con and the suction negative pressure P and the water temperature T obtained in step 38 described later are initialized.

Then, in step 34, the pressure sensor 7
The suction negative pressure signal Pa output from the water temperature sensor 13 and the water temperature signal Ta output from the water temperature sensor 13 are read. In step 35, the suction negative pressure signal Pa and the water temperature signal Ta read in step 34 are read in step 33. Initialized suction negative pressure P,
Each is added to the water temperature T, and in the next step 36, 1 is added to the number-of-times flag Con to store the number of measurements, and in step 37, it is determined whether or not the number-of-times flag Con has reached the set number of times Nst. When it is determined to be "NO" in this step 37, the number of times flag Con has not reached the set number of times Nst. Therefore, the process returns to step 34, and when it is determined to be "YES" in this step 37, the suction negative pressure signal is output. Read Pa and the water temperature signal Ta a set number of times Nst,
Since the suction negative pressure P and the water temperature T have been integrated respectively, the process proceeds to the next step 38.

Then, in step 38, the suction negative pressure P and the water temperature T accumulated in step 35 are divided by the set number of times Nst to obtain an average value, and in the next step 39, the averaged intake pressure is obtained. Based on the negative pressure P and the water temperature T, the set water temperature Tst is read from the P-T map shown in FIG.
The above-described water temperature control process shown in FIG. 5 is performed via the connector A. Here, the PT map includes a plurality of cooling water temperatures T1, T2,
The relationship between T3, ... (T1>T2> T3) and the suction negative pressure P is stored as a map. The P-T map has a proportional relationship in which the set water temperature Tst increases as the suction negative pressure P increases when the cooling water temperature T is constant.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same operational effects as those of the first and second embodiments.

Incidentally, in the above embodiment, FIG. 3, FIG. 8 and FIG.
The program shown in 0 is a specific example of the water temperature setting means that is a constituent feature of the present invention, and the program shown in FIG. 5 is a specific example of the water temperature control means that is a constituent feature of the present invention.

In the above embodiment, the flow control valve 21 is composed of the laminated piezoelectric material 25 and the like, and the drain pipe 8B of the supply / discharge pipe 8 is provided.
I said that it was installed in the middle of, but instead of this,
For example, another control valve such as an electric valve may be used as the flow rate control valve, and in some cases, the flow rate control valve may be attached to the water supply pipe 8A of the water supply / discharge pipe 8.

[0058]

As described in detail above, according to the present invention, the flow rate is provided in the middle of the supply / discharge pipe and controls the flow rate of the cooling water flowing between the water jacket and the radiator by a control signal from the outside. A control valve, a water temperature setting means for calculating the set water temperature of the cooling water based on the load state of the engine body, and a control signal to the flow control valve based on the set water temperature calculated by the water temperature setting means to output the cooling water. Since the water temperature control means for controlling the temperature of the cooling water to the set water temperature is provided, the set water temperature of the cooling water can be set based on the load state of the engine body, and the flow control valve is the radiator by the control signal from the water temperature control means. The flow rate of the cooling water flowing between the water jacket and the water jacket can be controlled to adjust the temperature of the cooling water to the set water temperature required by the water temperature setting means. Can be obtained engine output and fuel consumption in accordance with the state, it is possible to improve the engine performance by cooling the engine body efficiently.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an engine cooling device according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a flow control valve in FIG.

FIG. 3 is a flowchart showing a water temperature setting process according to the first embodiment of the present invention.

FIG. 4 shows the T stored in the control unit in FIG.
It is a p-N map.

FIG. 5 is a flowchart showing a water temperature control process.

FIG. 6 is a proportional value map showing the relationship between the duty amount Dp and the temperature difference ΔT.

FIG. 7 is an integral value map showing the relationship between the duty change amount Di and the temperature difference ΔT.

FIG. 8 is a flowchart showing a water temperature setting process according to the second embodiment of the present invention.

FIG. 9 is a θ-T map showing the relationship between the valve opening θ and the water temperature T.

FIG. 10 is a flowchart showing a water temperature setting process according to the third embodiment of the present invention.

FIG. 11 is a PT map showing the relationship between suction negative pressure P and water temperature T.

FIG. 12 is a block circuit diagram showing a conventional engine cooling device.

[Explanation of symbols]

 1 Engine Main Body 8 Supply / Exhaust Pipe 9 Radiator 10 Water Pump 21 Flow Control Valve 34 Control Unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F16K 31/02 A 9131-3H

Claims (4)

[Claims] 1. An engine main body having a water jacket in which cooling water circulates, and a supply / discharge pipe for supplying / discharging cooling water to / from the water jacket, the one end side of which is communicated with the water jacket of the engine main body. A radiator provided on the other end of the supply / discharge pipe for cooling the cooling water;
In an engine cooling device including a water pump provided in the middle of the supply / discharge pipe and forcibly circulating cooling water by driving the engine body, the engine cooling device is provided in the middle of the supply / discharge pipe, and the water is supplied by a control signal from the outside. A flow rate control valve for controlling the flow rate of the cooling water flowing between the jacket and the radiator, and a water temperature setting means for calculating the set water temperature of the cooling water based on the load state of the engine body,
An engine cooling device comprising: a water temperature control unit that outputs a control signal to the flow control valve based on the set water temperature calculated by the water temperature setting unit to control the temperature of the cooling water to the set water temperature. 2. The engine cooling device according to claim 1, wherein the water temperature setting means is configured to detect a load state of the engine body from a basic injection amount and an engine speed. 3. The engine cooling device according to claim 1, wherein the water temperature setting means is configured to detect a load state of the engine main body from a valve opening of a throttle valve and a water temperature of cooling water. .. 4. The engine cooling device according to claim 1, wherein the water temperature setting means is configured to detect a load state of the engine body from a suction negative pressure and a water temperature of cooling water.