JPH042772B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cooling system control device for a water-cooled internal combustion engine, and in particular detects the temperature of the cooling water of a water-cooled jacket and the cylinder, thereby preventing rapid temperature changes. The present invention relates to a cooling system control device for a water-cooled internal combustion engine that can operate a cooling system accordingly.

[Technical background of the invention and its problems]

Generally, in a water-cooled internal combustion engine, if the cooling fan is driven when the temperature of the cooling water is low, it becomes difficult to start the engine. In order to solve this problem, the cooling system of the engine is controlled, and a device is used in which a fluid clutch is installed in the cooling fan and the cooling fan is driven as the temperature of the cooling water increases. However, in this device, the thermostat is not designed to directly detect the temperature of the cooling water, but instead uses an indirect detection method installed near the radiator. For this reason, a thermostat works by controlling the temperature of the cylinder wall when the combustion load becomes high, and then the temperature of the cooling water, which heats the radiator and heats the air that passes through the heated radiator. Finally, the heated air goes through a very complicated system that heats the thermostat before it is activated. Therefore, the response delay cannot be resolved unless the operating temperature of the thermostat is set considerably lower than the specified cooling water temperature, and even if it were resolved, reliable control cannot be expected since indirect detection is used. ,
Furthermore, since the engine cannot cope with rapid temperature changes, the engine may burn out.

Additionally, both the cooling fan and the circulation pump are driven using part of the engine horsepower, but in the past, this drive was not done individually, but rather as an integral control system in which the pump operated when the cooling fan moved. Ta. Therefore, in addition to the above-mentioned inaccuracy due to indirect temperature detection, the simultaneous operation of both of them causes an overcooling region. In this region, a portion of the engine horsepower was wasted due to unnecessary cooling, and the horsepower could not be used effectively.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and by directly detecting the temperature of the cylinder and water cooling water, it operates to follow rapid temperature changes in the engine and eliminates problems such as piston seizure. It is an object of the present invention to provide a cooling device for a water-cooled internal combustion engine, which can control the pump and fan individually to reduce the drive horsepower required by the pump and fan at a given time and increase the output. .

[Structure of the invention]

The present invention is configured as follows in order to achieve such an object. The temperature of the cooling water and the cylinder do not necessarily match, and if the temperature of the cooling water is low, driving the fan further when starting the engine, at low load, or at low speed may make the engine run harder or cause a reduction in output. In order to prevent this, the temperatures of both the cylinder and the cooling water are detected separately, and the fan and pump drives are individually controlled using the detected outputs. In order to perform this control, temperature sensors such as positive characteristic thermistors are embedded in the water cooling jacket for water cooling the internal combustion engine and in the cylinder walls that make up the internal combustion engine, and two parameters, the cooling water temperature and the cylinder temperature, are controlled. It is considered a factor. on the other hand,
A control circuit is provided in which these two parameters are input and four temperatures to be compared with are set in advance. These four set temperatures are set separately for one parameter as low temperature and high temperature, and when the parameter input is below the low temperature setting, the pump is activated.
It has the role of turning off the fan when it is OFF and turning ON when it is above the high temperature set value, and turning the fan OFF when it is below the high temperature set value and ON when it is above it. If any one of the cylinder or cooling water temperatures shows a temperature lower than each low temperature setting value set correspondingly, the pump operation is stopped; The control circuit is configured to operate the pump only when both exceed the respective low temperature set values, and is connected to the output sides of the two temperature sensors. In addition, this control circuit also stops the rotation of the fan if any one of the cylinder or cooling water temperatures is lower than the corresponding high temperature setting value, and reverses the rotation of the fan. The engine is equipped with a function that rotates the fan only when both the cylinder and cooling water temperatures exceed respective high temperature set values, thereby controlling the engine cooling system.

[Embodiments of the invention]

A preferred embodiment of the cooling system control device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a cooled internal combustion engine showing one embodiment of the present invention. As shown in the figure, the cooling water internal combustion engine has a water cooling jacket 1 for water cooling the internal combustion engine.
, a radiator 2 for radiating and cooling the cooling water of the jacket 1, a pump 3 for circulating the cooling water between the water cooling jacket 1 and the radiator 2, and a filter fan 4 for air cooling the radiator 2. It is equipped with A cylinder temperature sensor _S1 made of, for example, a positive temperature coefficient thermistor is embedded in a part of the wall surface 6 facing the cylinder 5 constituting the internal combustion engine to detect the wall surface temperature. Further, a jacket temperature sensor _S2 for detecting the cooling water temperature is attached to a part of the water cooling jacket 1. The outputs of the jacket temperature sensor _S2 and the cylinder temperature sensor _S1 are both connected to a control circuit C which operates using the battery 7 as a power source. This control circuit C
As shown in Fig. 2, there are four comparator circuits 8 and two
It consists of an AND circuit 9 and one control voltage generation circuit 10. A reference voltage corresponding to a predetermined temperature is individually set for each comparison circuit 8. The _T1 comparison circuit 8a and the _T3 comparison circuit 8b each have a first set temperature _T1 set at a relatively low temperature and a third set temperature _T3 set at a relatively high temperature as their reference voltages. are commonly connected to the output side of the cylinder temperature sensor _S1 . Further, a T ₂ comparison circuit 8c and a T ₄ comparison circuit 8d each have a second set temperature T ₂ which is also set at a low temperature and a fourth set temperature T ₄ which is set at a higher temperature than this as their reference voltages. is a jacket temperature sensor with a common input.
Connected to the output side of _S2 . Each comparator circuit 8 outputs "1" when the input signal is greater than the reference voltage, but among these, the _T1 comparator circuit 8a output and the _T2 comparator circuit 8c output are connected to one AND circuit 9a, and both output The output is sent to the control voltage generating circuit 10 only when both are "1". Further, the output of the other T ₃ comparison circuit 8b and the output of the T ₄ comparison circuit 8d are connected to the other AND circuit 9b, and similarly, only when both outputs are "1", the control voltage generation circuit 10
It is designed to input signals to. In the control voltage generation circuit 10, one AND circuit 9a output is “1”
When the output of the other AND circuit 9b is "1", a low voltage is generated, and when the output of the other AND circuit 9b is "1", a high voltage is generated, and the electromagnetic force of the electromagnet, which will be described later, is controlled in two stages.

The output of the control circuit C is connected to an electromagnetic clutch 11 mounted on a transmission pulley of a pump 3 and a fan 4 provided at the front of the internal combustion engine. This clutch mechanism is shown in detail in FIG.
A shaft 14 is rotatably mounted on the front surface of the internal combustion engine, and has an armature 13 rotatably attached to one end of which a blade wheel 12 constituting a pump 3 is attached, and a fan 4 fixed to the other end.
is provided, and this shaft is also rotatable. A rotor 17 is disposed coaxially with the shaft 14 to which rotation of the crankshaft 16 is transmitted via a V-belt 15. An electromagnetic coil 18 connected to the output of the control circuit C is attached to the rotor 17, and the rotor 17 constitutes one electromagnet. The rotor electromagnet is integrally fixed to the shaft 14 in parallel with the armature 13, and is supported by a spring 19a.
A first electromagnetic clutch 11a is formed from another armature 21 having a contact 20a at its tip via a spring 19b, and a second electromagnetic clutch 13 from the armature 13 having a contact 20b at its tip via a spring 19b. It forms an electromagnetic clutch 11b. The spring 19b of the second electromagnetic clutch 11b has a greater force against electromagnetic attraction than the spring 19a used in the first electromagnetic clutch 11a. Therefore, when there is no output from the control circuit C, both the pump 3 and the fan 4 do not operate, but the control circuit C
When the output becomes a low voltage output, the first electromagnetic clutch 1
1a to operate the rotating shaft 14 of the rotor 17.
and drives the pump 3. Furthermore, when a high voltage output is generated, the current flowing through the electromagnetic coil 18 increases and the electromagnetic attraction force becomes larger than the resistance force of the spring 19b, so the second electromagnetic clutch 11b operates and the rotation of the rotor 17 is controlled only by the shaft 14. At the same time, the power is transmitted to the armature 13 and the fan 4 is rotated. That is, depending on the magnitude of the control output, the pump 3 and fan 4 are controlled individually rather than together. Therefore, it is of course possible to use clutch mechanisms other than electromagnetic clutches as long as they can be individually controlled.

The operation of the present control device having the above configuration will be described. Now, since the engine is cold, the engine speed or load is gradually increasing and the cylinder 5
Consider the case where the wall temperature increases. Note that the opposite is true when the temperature decreases. In this case, the present control device controls and drives the pump 3 and fan 4 in the following three ways. This will be explained with reference to FIG.

First, the cylinder wall surface 6 temperature _T3 detected by the cylinder temperature sensor _S1 is the first set temperature _T1.
and below, and when the cooling water temperature T _W detected by the jacket temperature sensor S ₂ is lower than the second set temperature T ₂ or even if T _S is higher than T ₁ , T _W is T ₂
In the following cases or even if T _W is T ₂ or more, T _S is
When it is in the unhatched region _Z1 in FIG _. 4, which is less than T1, not only the fan 4 but also the pump 3 are not operated. Under such conditions,
Since the outputs of T ₃ and T ₄ comparison circuits 8b and 8d both remain "0", the other output which outputs the fan operation signal
The output of the AND circuit 9b is “0”, and T ₁ ,
Since one of the outputs of the T ₂ comparison circuits 8a and 8c is always "0" and never both becomes "1", the output of the AND circuit 9a, which outputs the pump operation signal, also becomes "0". Therefore, the control voltage generating circuit 10 does not operate at all, the output of the control circuit C becomes "0", and no current flows through the electromagnetic coil 18. Therefore, part of the engine horsepower is not wasted to drive the pump 3 or fan 4, and the cooling water remains in a stagnant state and is not circulated or cooled by the radiator 2. , engine driving can be performed effectively.

Next, when the cylinder temperature T _S enters a hatched area Z ₂ indicating that the cylinder temperature T S is higher than the first set temperature T ₁ and the cooling water temperature T _W is higher than the second set temperature T ₂ , only the pump 3 is activated. In this state, the internal combustion engine is cooled by the cooling water circulated by the pump 3.
This is because the outputs of the T ₁ comparison circuit 8a and the T ₂ comparison circuit 8c both become "1", and a low voltage output is generated from the control circuit C, turning on the first electromagnetic clutch 11a. Even if T _S is higher than the third set temperature T ₃
If T _W is equal to or lower than the fourth set temperature, T _W
Even if T _S is greater than or equal to T ₄ , if T S is less than or equal to T ₃ , the output of the other AND circuit 9b, which outputs the fan activation signal, will not become "1" and the fan 4 will remain stopped. Therefore, the temperature rise of the internal combustion engine at this stage can be suppressed only by circulating the cooling water by operating the pump 3, saving 4 to 5 PS of fan drive horsepower and only requiring 2 to 3 PS of pump drive horsepower. You can get away with it.

The third state is when the cylinder temperature T _S is at least T ₃ and the cooling water temperature T _W is at least T ₄ in the region shown by cross hatching.
In addition to the operation of the fan 4, the fan 4 also rotates. This is because the outputs of the T ₃ and T ₄ comparison circuits 8b and 8d both become "1", a high voltage is output from the control circuit C output, and the second electromagnetic clutch 11b is also turned on. Therefore, the heated cooling water is cooled by the fan 4 in the radiator 2, making it possible to effectively cool the internal combustion engine. In addition, since the temperature of the cooling water and the cylinder wall surface 6 is directly detected and the pump 3 and fan 4 are controlled by this detection output, the response is fast, especially when the cylinder temperature T _S and the cooling water temperature T _W are high. ₃ and _T4 , the fan 4 is activated immediately, thereby avoiding engine burnout.

For convenience, each set temperature T of the comparator circuit 8 has been explained using a single value, but if the temperature is a single value, the output of the comparator circuit 8 will become unstable near that temperature, and the electromagnetic clutch 11 will become unstable.
Problems arise in terms of noise and durability when turning ON and OFF repeatedly. Therefore, as shown in FIG. 5, it is actually desirable to set two values with slight differences such as ON temperature and OFF temperature. That is, each set temperature T consists of a higher ON temperature and a lower OFF temperature, and when the detected temperature exceeds the ON temperature, the comparator circuit 8 enters the ON region, and when it falls below the OFF temperature,
Make it the OFF area for the first time.

Figure 6 shows the cylinder temperature, the upper limit of the cooling water temperature,
1st to 4th set temperature from the lower limit temperature
T ₁ to _{T 4} are determined, and the operating range of the pump 3 and fan 4 obtained from these values is determined in terms of the relationship between the engine speed and the load. Than this,
It can be seen that the pump 3 and fan 4 may be driven only partially during partial loads and low speed rotations that are generally used in vehicles. In more detail, as mentioned above, the fan drive horsepower 4 to 5 PS and the pump drive horsepower 2 to 3 PS are unnecessary, especially at low load high speed rotation, and furthermore, it is expected that the output will increase during low temperature sudden acceleration, and the fuel consumption at partial load will be reduced. An improvement of 2-3% is obtained.

〔Effect of the invention〕

In summary, the present invention exhibits the following excellent effects.

(1) By providing not only a jacket temperature sensor but also a cylinder temperature sensor, the cooling system can be activated in response to rapid temperature changes, especially on the cylinder wall surface, thereby eliminating problems such as piston seizure.

(2) By individually controlling the pump and fan using the two temperature parameters of cooling water temperature and cylinder temperature, the engine cooling system operates ideally and effectively utilizes the horsepower required to drive the pump and fan. can be used. In particular, the pump and fan horsepower are not required during low-load, high-speed rotation, and not only is it possible to expect an increase in output during low-temperature rapid acceleration, but it is also possible to improve fuel efficiency during partial load.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a water-cooled internal combustion engine to which a preferred embodiment of the cooling system control device according to the present invention is applied;
Fig. 2 is a block diagram explaining the control circuit in Fig. 1, Fig. 3 is an enlarged view showing details of the pump and fan clutch mechanism in Fig. 1, and Fig. 4 is a pump controlled based on detected temperature. Fig. 5 is a diagram showing the operating state of the control system when hysteresis is provided for the set temperature. Fig. 6 is an explanatory diagram showing the operating range of the pump and fan, and Fig. 6 is an explanatory diagram showing the operating range of the pump and fan. This is a diagram that is understood in terms of relationships. In the figure, 1 is a water cooling jacket, 2 is a radiator, 3 is a pump, 4 is a fan, 5 is a cylinder, S ₁
is the cylinder temperature sensor, _S2 is the jacket temperature sensor, C is the control circuit, _T1 is the first set temperature, _T2 is the second set temperature, _T3 is the third set temperature, and _T4 is the fourth set temperature. The set temperature, T _S is the cylinder temperature, and T _W is the cooling water temperature.

Claims (1)

[Claims] 1 Temperature sensors are provided on the cylinder and the water cooling jacket, respectively, and when the cylinder temperature is equal to or higher than the first set temperature and the cooling water temperature is equal to or higher than the second set temperature.
The cooling water pump is operated when the temperature is higher than the set temperature, and the radiator fan is activated when the cylinder temperature is higher than the third set temperature, which is higher than the first set temperature, and the cooling water temperature is higher than the fourth set temperature, which is higher than the second set temperature. 1. A cooling system control device for a water-cooled internal combustion engine, characterized in that a control circuit for controlling the water-cooled internal combustion engine is connected thereto.