JPS64573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine cooling device, and particularly to a water-cooled cooling device.

Engines used in automobiles and the like are generally equipped with a cooling device to prevent the engine from overheating. Conventionally, this cooling system generally includes a water jacket provided in a cylinder head and a cylinder block, a water pump for urging a flow of cooling water through the water jacket, a radiator, and an outlet of the water jacket connected to an inlet of the water jacket. a first reflux passage (bypass passage) that connects the outlet of the water jacket to its inlet and does not include the radiator on the way; and a control valve that selectively shuts off the recirculation passage, and the control valve operates according to the temperature of the cooling water flowing through the water jacket, and closes when the temperature is below a predetermined value. One of the reflux passages is shut off, and when the temperature is above a predetermined value, communication of the first reflux passage is established.

By the way, in engines that use liquid fuel such as gasoline, when the engine is cold, the fuel sucked into the engine combustion chamber is not sufficiently vaporized.
This causes instability in the amount of fuel supplied to each cylinder,
Combustion becomes unstable and combustion varies between cylinders, resulting in lower engine drivability compared to after warm-up is complete. In order to prevent this deterioration in drivability when the engine is cold, it has conventionally been common practice to increase the amount of fuel supplied when the engine is cold, using a choke device or the like, compared to when the engine is warmed up. If the amount of fuel is increased when the engine is cold, the deterioration in drivability when the engine is cold can be avoided, but there are disadvantages such as an increase in fuel consumption and an increase in HC and CO components in the exhaust gas.

Further, in a carburetor type engine, a riser portion of an intake manifold is heated using exhaust heat or an electric heater to promote vaporization of fuel. However, even if the fuel is vaporized when passing through the riser portion, if the wall surface temperature of the intake port is low, there is a problem in that the fuel is cooled when passing through the intake port and a portion of it liquefies again. Furthermore, since fuel injection engines are generally structured to inject fuel near the intake valve, it is difficult to fully utilize exhaust heat, electric heaters, etc. to vaporize the fuel.

In order to solve the above-mentioned problems, it is effective to rapidly increase the wall temperature of the intake port after the engine starts. It is necessary to rapidly raise the temperature of the cooling water.

However, in the currently commonly used cooling system as described above, the temperatures of the water jacket of the cylinder head and the water jacket of the cylinder block are always maintained at approximately the same temperature, and when the engine is cold, the temperature of the water jacket of the cylinder head and the water jacket of the cylinder block are maintained at approximately the same temperature. Since a large amount of heat transferred to the cooling water is consumed by the cylinder block, which has a large heat capacity, it is impossible to rapidly raise the temperature of the cooling water after starting the engine.

The cooling water return passage including the water jacket of the cylinder head and the cooling water return passage including the water jacket of the cylinder block are made independent from each other,
The cooling system is designed to prevent the amount of heat transferred from the cylinder head to the cooling water when the engine is cold from being consumed in the cylinder block, and to rapidly raise the temperature of the cooling water in the water jacket of the cylinder head after the engine is started. It is considered. However, with this cooling system, the rise in the temperature of the cooling water in the cylinder block water jacket is much slower than with conventional systems, and as a result, the temperature of the engine lubricating oil, which is greatly affected by the temperature of the cooling water, is The increase in fuel consumption is delayed, leading to an increase in fuel consumption due to friction loss.

In view of the above-mentioned problems with conventional cooling systems, the present invention has been developed to rapidly increase the temperature of the cooling water flowing through the water jacket of the cylinder head after starting the engine, and to reduce the temperature of the cooling water flowing through the water jacket of the cylinder block. It is an object of the present invention to provide an improved cooling system for an engine that does not significantly retard lift or cause overheating of either the cylinder head or the cylinder block.

According to the invention, this object is achieved by providing a first water jacket provided on the cylinder head, a second water jacket provided on the cylinder block, and a water pipe passing through the first and second water jackets. a water pump that energizes the flow of cooling water;
a radiator, a first return passage connecting the outlets of the first and second water jackets to their inlets, and including the radiator in the middle; a second return passage connected to the inlet and not including the radiator; a first temperature sensor for detecting a temperature representative of the temperature of the cooling water flowing through the first water jacket; a second temperature sensor that detects a temperature representative of the temperature of the cooling water passing through the water jacket; and a temperature that is both detected by the first temperature sensor and the second temperature sensor. a first control valve that limits the flow rate of cooling water flowing through the second water jacket when the temperature is below a first predetermined value; This is achieved by an engine cooling device characterized in that it has a second control valve that establishes communication with the first recirculation passage when the temperature exceeds a second predetermined value that is higher than the predetermined value.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a diagram showing one embodiment of an engine cooling device according to the present invention. In Figure 1, 1
1 shows an engine, and this engine 1 mainly has a cylinder head 2 that defines the head of the combustion chamber of each cylinder, and a cylinder block 3 that defines the peripheral wall of the combustion chamber. The cylinder head 2 and cylinder block 3 are respectively provided with water jackets 4 and 5, and cooling water flows through these water jackets in independent flows. .

The inlet 6 of the water jacket 4 is connected to the discharge port of the water pump 11 through a conduit 10, and the inlet 7 of the water jacket 5 is connected to the discharge port of the water pump 11 through a conduit 13 that includes a control valve 12 in the middle. ing. Outlets 8, 9 of water jackets 4 and 5 are connected to one port of control valve 17 via conduits 14, 15 and 16, respectively. The control valve 17 is connected at its other port via a conduit 18 to an inlet 20 of the radiator 19. The radiator 19 is connected at its outlet 21 via a conduit 22 to the suction port of the water pump 11. Further, the conduit 16 and the conduit 22 are connected to each other by a bypass conduit 23 having a smaller diameter than these conduits. Water pump 11 is engine 1
It is designed to be driven by

24 indicates a heater core for heating the inside of the car.
This heater core is connected to conduit 16 via conduit 25 at its inlet and to conduit 1 via conduit 26 at its outlet.
6, respectively. An on-off valve 27 is provided in the middle of the conduit 25, and this on-off valve is opened only when heating the vehicle interior, so that a portion of the cooling water flowing through the conduit 16 flows to the heater core 24.

28 is a control device for controlling the operation of control valves 12 and 17. This control device uses a temperature signal generated by a water temperature sensor 29 provided in the conduit 16 and a water temperature sensor 30 provided in the cylinder block 3.
The generated temperature signal is input. The water temperature sensor 29 detects the temperature of the cooling water flowing through the conduit 16, which detects the temperature of the cooling water flowing out from the water jacket 4 when the control valve 12 is closed, and detects the temperature of the cooling water flowing out from the water jacket 4 when the control valve 12 is opened. When this is done, the temperature of the mixed cooling water of the cooling water flowing out from the water jacket 4 and the cooling water flowing out from the water jacket 5 is detected. Water temperature sensor 30 detects the temperature of the cooling water flowing through water jacket 5.

The control device 28 may be a microcomputer, and controls when the temperature of the cooling water detected by the water temperature sensor 29 and the temperature of the cooling water detected by the water temperature sensor 30 are both below a first predetermined value, for example, 80°C. outputting a valve closing signal to the valve 12, and outputting a valve opening signal to the control valve 12 when at least one of the two cooling water temperatures is equal to or higher than the first predetermined value;
Further, when both of the two temperatures are at a second predetermined value higher than the first predetermined value, for example, 85° C. or less, a valve closing signal is sent to the control valve 17, and at least one of the two temperatures is set to a second predetermined value. When the value exceeds a predetermined value, a valve opening signal is output to each control valve 17.

Next, the operation of the cooling device constructed as described above will be explained.

First, after starting the engine, the water temperature sensor 29
A case will be described in which the temperature detected by the water temperature sensor 30 and the temperature detected by the water temperature sensor 30 are both below the first predetermined value, that is, the engine is being warmed up (when the engine is cold). At this time, both control valves 12 and 17 are closed by a command signal generated by the control device 28. At this time, therefore, none of the cooling water delivered by the water pump 11 flows into the water jacket 5, but all of it flows into the water jacket 4 via the conduit 10 and flows through it, with no heat is received from the engine 1, and is transferred to the water pump 1 via conduits 14, 16, bypass conduit 23, and conduit 22.
Return to 1.

The amount of heat received by the cooling water from the engine 1 is usually larger in the water jacket 4 than in the water jacket 5, and in a normal engine, the cylinder head has a higher heat capacity. Since it is smaller than the cylinder block, when the cooling water circulates only through the water jacket 4 of the cylinder head 2, as mentioned above, the temperature of the cooling water increases several times faster than that of the water jacket 5 of the cylinder block 3. Therefore, the wall surface temperature of the intake port, which is strongly influenced by the temperature of the cooling water in the water jacket of the cylinder head, rapidly rises, and the vaporization of the fuel taken into the engine combustion chamber through the intake port is promoted.

This not only makes it possible to shorten the choke time when the engine is cold compared to the conventional technology, but also improves fuel efficiency and exhaust gas performance, as well as improves drivability when the engine is cold. Furthermore, since the temperature of the cooling water in the water jacket 4 rises quickly, the heater and defroster start up quickly, improving comfort and safety in severe cold weather. In addition, in the case where the dizer section of the intake manifold is heated by cooling water, the temperature of the riser section rises quickly, and the vaporization of the fuel is further promoted.

As the engine 1 operates, the temperature of the cooling water flowing through the water jacket 4 increases, and when the water temperature sensor 29 detects that the temperature exceeds the first predetermined value, the control device 28 issues a command. Only the control valve 12 is opened by the signal. Therefore, at this time, a part of the cooling water sent by the water pump 11 flows into the water jacket 4 through the conduit 10 and circulates through the same route as when warming up the engine, but the remaining cooling water flows through the conduit. 13 and the control valve 12 into the water jacket 5, flows through the water jacket and flows through the conduit 15 to the conduit 16, where it joins the cooling water flowing out from the water jacket 4, Furthermore, it returns to the water pump 11 via the bypass conduit 23.

In this way, the cooling water flowing out from the water jacket 4 and the cooling water flowing out from the water jacket 5 join together, so that the cooling water flowing out from the water jacket 5 is hotter than the cooling water flowing out from the water jacket 4. As a result, the temperature of the cooling water flowing into the water jacket 5 rapidly rises. As a result, the temperature of the engine lubricating oil, which is strongly affected by the cylinder block side cooling water temperature, also increases, and engine friction loss is reduced, resulting in improved fuel efficiency and exhaust performance. At the same time, the cylinder head 2 side of the engine 1 is prevented from becoming heated.

When the engine is cold as described above, a large amount of heat is removed from the cooling water flowing out from the water jacket 4 by the heater or riser heating, and before the temperature reaches the first predetermined value, the water jacket 4 cools. 5 rises and reaches the first predetermined value, this indicates that the water temperature sensor 3
0 is detected, and the control valve 12 is opened. As a result, water jacket 4 can also be used at this time.
The cooling water flowing through the water jacket 5 and the cooling water flowing through the water jacket 5 mix with each other, and the temperature of the cooling water flowing through the water jacket 5 is reduced by averaging the temperatures of the two cooling waters. This prevents the cylinder block 3 side of the engine 1 from becoming overheated.

When the cooling water in the water jacket 5 and the cooling water in the water jacket 4 mix with each other,
The temperature of the cooling water flowing through the water jacket 4 or the water jacket 5 may drop, and this temperature may fall below the first predetermined value again. In this case, water jacket 4
The control valve 12 repeats opening and closing until the temperature of the cooling water in the water jacket 5 becomes substantially equal to the temperature of the cooling water in the water jacket 5 and the temperature exceeds the first predetermined value. The control valve 12 continues to open when the temperatures of the cooling water in the water jackets 4 and 5 both exceed a first predetermined value.

Next, when the temperature detected by the water temperature sensor 29 or 30 exceeds a second predetermined value, the control valve 17 is also opened by a command signal generated by the control device 28. At this time, part of the cooling water that has flowed through the conduit 16 returns to the water pump 11 via the bypass conduit 23, but since the diameter of the bypass conduit 13 is small,
Most of the cooling water passes through the control valve 17 and the conduit 18 to the radiator 19, is cooled as it flows through the radiator, and passes through the conduit 21 to the water pump 11.
Return to

When the temperature of the cooling water rises above the second predetermined value, the cooling water is cooled in the radiator 19 and the water jacket 4 is cooled.
and 5 are maintained at approximately the second predetermined value, thereby avoiding overheating of the engine 1.

From the above explanation, according to the cooling system of the present invention, the temperature of the cooling water in the water jacket of the cylinder head after the engine starts can be increased more rapidly than in the conventional system, thereby reducing the amount of liquid fuel taken into the engine. Further, the warm-up of the cylinder block is not significantly delayed, and neither the cylinder head nor the cylinder block is brought into a heated state.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of an engine cooling device according to the present invention. 1...Engine, 2...Cylinder head, 3...
...Cylinder block, 4,5...Water jacket, 6,7...Inlet, 8,9...Outlet, 10...
... Conduit, 11 ... Water pump, 12 ... Control valve, 13-16 ... Conduit, 17 ... Control valve, 18
... Conduit, 19 ... Radiator, 20 ... Inlet,
21... Outlet, 22... Conduit, 23... Bypass conduit, 24... Heater core, 25, 26... Conduit, 27... Control valve, 28... Control device, 29,
30...Water temperature sensor.

Claims (1)

[Claims] 1 A first water jacket provided on the cylinder head, a second water jacket provided on the cylinder block, and a water pump for urging a flow of cooling water through the first and second water jackets. , a radiator, a first return passage connecting the outlets of the first and second water jackets to their inlets and including the radiator in the middle, and connecting the outlets of the first and second water jackets to the inlets thereof. a second return passage connected to the inlet of the water jacket and not including the radiator in the middle; a first temperature sensor that detects a temperature representative of the temperature of the cooling water flowing through the first water jacket; a second temperature sensor that detects a temperature representative of the temperature of the cooling water passing through the water jacket; and one of the temperatures detected by the first temperature sensor and the second temperature sensor. a first control valve that limits the flow rate of cooling water flowing through the second water jacket when the temperature is below a first predetermined value; a second control valve that establishes communication with the first recirculation passage when the temperature is at least a second predetermined value higher than a predetermined value.