JP2000345842A - Cooling water control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely control cooling water temperature, expand a lean combustion region, and improve exhaust gas and fuel consumption performance. SOLUTION: This control device has combustion temperature in the same engine rotation frequency and load condition, or plural combustion conditions having different heat transfer rates to engine cooling water, cools an engine by a water cooling method, radiates the heat of the engine cooling water by a radiator 2, assists heat radiation through this radiator 2 by an electric fan 10, and has a passage 5 for bypassing a passage to the radiator 2 when engine cooling water temperature has given temperature or less. In this case, this device is equipped with a means 7 for specifying the operation condition of the rotation frequency or load condition, etc., of the engine, a means 9 for detecting the condition of present cooling water temperature, and a means 7 for specifying an engine combustion mode, to calculate the engine cooling water temperature variation in a given time of engine cooling water temperature from cooling water temperatures detected before a given time and at present.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water control device for an internal combustion engine having a plurality of combustion states having different combustion temperatures or different heat transfer rates to engine cooling water at the same rotation speed and the same load state.

[0002]

2. Description of the Related Art Fuel is injected in a plurality of combustion states, for example, during an intake stroke under the same rotation and the same load state, and the ratio between the intake air amount and the fuel amount (hereinafter referred to as A / F) is controlled by stoichiometry. Mode (hereinafter referred to as stoichio)
Similarly, fuel is injected during the intake stroke, but A / F is set to a lean mode (hereinafter referred to as intake lean) or fuel is injected during the compression stroke, and the A / F is further set to lean. 2. Description of the Related Art An internal combustion engine having a mode (hereinafter, referred to as a compression lean) has been conventionally known.

[0003] A water-cooled internal combustion engine is usually constructed so that the excess heat generated during combustion in the engine is transmitted to cooling water so that the temperature of the engine itself does not rise excessively. It is configured to exchange heat with a radiator in order to radiate heat to air. In addition, in order to assist heat exchange in the radiator, the fan is generally blown to the radiator core by an electric motor (hereinafter referred to as a radiator electric fan) to be cooled.

At this time, when the temperature of the engine cooling water is lower than the predetermined temperature, cooling by the radiator electric fan is unnecessary, so that the motor is not stopped and air is blown. Is controlled so as to perform blast cooling.

In addition, when the temperature of the engine cooling water is equal to or lower than a predetermined temperature which is different from the above, the cooling by the radiator is usually unnecessary during the warming-up of the engine from the viewpoint of promoting the warming-up of the engine. A bypass passage is provided to detour, and a thermo-wax type bypass valve whose opening degree changes mechanically in accordance with the temperature is usually provided to switch this passage. The passage is switched accordingly. Thus, in the conventional cooling water control device for an internal combustion engine, the engine temperature is controlled within a predetermined range.

[0006]

However, the above-mentioned conventional cooling water control apparatus for an internal combustion engine has the following problems. First, the engine cooling control is considered for an internal combustion engine that does not have a plurality of conventional combustion states and burns in stoichiometry, and the cooling capacity of the internal combustion engine depends on the usage state of the internal combustion engine and the amount of generated heat. For this reason, the amount of cooling water, the size of the radiator, and the like are set so that the temperature of the engine cooling water basically rises without assistance from the radiator electric fan, that is, so that excessive cooling is not performed.

However, the above-mentioned internal combustion engine has a combustion state different from the conventional one, and in the combustion state other than the stoichio, generally, the amount of generated heat is smaller than that of the stoichio, and the amount of heat transferred to the cooling water is also smaller. Therefore, the cooling capacity of the cooling system set by the above method becomes excessive in this mode, and it takes a long time to warm up the engine. As a result, fuel efficiency and exhaust gas deteriorate. Cannot be used for the purpose. Further, at this time, if the cooling system is designed based on the combustion state where the heat generation amount is small, the cooling capacity becomes insufficient in a region where the heat generation amount becomes maximum, and a problem such as overheating occurs.

[0008] Also, in the engine cooling water control after the completion of engine warm-up, when a lean combustion state with a small heat generation is used, a cooling system designed based on the stoichiometric standard with a large heat generation has an excessive cooling capacity. Even when the radiator electric fan is stopped, the temperature of the cooling water becomes uncontrollable in which the cooling water temperature decreases. Also, at this time, if the cooling system is designed based on the combustion state where the heat generation amount is small, the cooling capacity becomes insufficient in the region where the heat generation amount becomes maximum, the radiator electric fan operates frequently, and the engine becomes A problem such as deterioration of fuel efficiency occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and it is possible to precisely control the temperature of cooling water, expand a lean combustion region, and improve exhaust gas and fuel efficiency. It is an object of the present invention to obtain a cooling water control device for an internal combustion engine that can perform the control.

[0010]

According to a first aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine, wherein a plurality of combustions having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water under the same engine speed and the same load condition. It has a state, cools the engine by a water cooling system, performs heat radiation of the engine cooling water by a radiator, assists heat radiation by the radiator by an electric fan, and, when the engine cooling water temperature is lower than a predetermined temperature, passes the passage to the radiator. A cooling water control device for an internal combustion engine having a bypass passage, a means for specifying an operating state such as an engine speed and a load state, a means for detecting a current cooling water temperature state, and a combustion mode of the engine. An engine cooling water temperature change amount for a predetermined time of the engine cooling water temperature from the cooling water temperature detected a predetermined time ago and the current cooling water temperature. It is obtained by way.

According to a second aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine according to the first aspect of the present invention, further comprising means for storing an engine cooling water temperature rise determination value in advance. The value is compared with the engine coolant temperature change amount to detect that the engine coolant temperature rise amount during a predetermined period is equal to or more than a predetermined amount.

According to a third aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine according to the second aspect of the present invention, wherein the rotation speed of the internal combustion engine, the throttle opening, the intake air amount, and the intake pipe pressure are determined.
The engine cooling water temperature rise determination value is changed based on two values of the engine load obtained from at least one of the two.

According to a fourth aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine according to the second or third aspect, wherein the engine cooling water temperature rise determination value is changed based on a combustion state of the internal combustion engine. is there.

According to a fifth aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine according to any one of the second to fourth aspects of the present invention, which controls operation of a vehicle interior heater blower mounted on a vehicle equipped with an internal combustion engine. The engine cooling water temperature rise determination value is changed.

According to a sixth aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine having a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state. The engine is cooled by, the heat radiation of the engine cooling water is performed by a radiator, the heat radiation by the radiator is assisted by an electric fan, and a passage that bypasses a passage to the radiator when the engine cooling water temperature is equal to or lower than a predetermined temperature, A cooling water control device for an internal combustion engine having a bypass valve capable of electrically adjusting a flow rate of the radiator and a bypass passage, wherein a means for detecting a current cooling water temperature state, and a means for specifying a combustion mode of the engine The opening degree of the bypass valve is controlled according to the combustion mode of the engine and the detected coolant temperature.

According to a seventh aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine according to the sixth aspect of the present invention, further comprising means for storing an engine cooling water temperature rise determination value in advance. From the water temperature and the current cooling water temperature, calculate the engine cooling water temperature change amount for a predetermined time of the engine cooling water temperature,
When the engine cooling water temperature change amount is smaller than the engine cooling water rise determination value, the bypass valve is opened to bypass the radiator.

According to a seventh aspect of the present invention, in the cooling water control device for an internal combustion engine according to the seventh aspect of the present invention, when the engine cooling water temperature is equal to or lower than a predetermined temperature, The bypass valve is opened to bypass the radiator.

According to a ninth aspect of the present invention, in the cooling water control device for an internal combustion engine according to the seventh or eighth aspect of the present invention, the opening degree of the bypass valve is controlled by changing the engine cooling water temperature change amount and the engine cooling water temperature rise. The flow distribution between the radiator and the bypass passage is adjusted by performing control in accordance with the deviation of the determination value.

According to a tenth aspect of the present invention, there is provided a cooling water control apparatus for an internal combustion engine having a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state. Cooling the engine, radiating the engine cooling water with a radiator, assisting the heat radiation by the radiator with an electric fan, and having a passage that bypasses a passage to the radiator when the temperature of the engine cooling water is equal to or lower than a predetermined temperature. A cooling water control device for an internal combustion engine including a radiator and a bypass valve capable of electrically adjusting a flow rate of a bypass passage, wherein a means for detecting a current cooling water temperature state, and a means for specifying a combustion mode of the engine. The operation of the electric fan is controlled based on the specified combustion state.

According to an eleventh aspect of the present invention, in the cooling water control device for an internal combustion engine according to the tenth aspect, the rotation start water temperature of the electric fan is changed based on the specified combustion state.

According to a twelfth aspect of the present invention, in the cooling water control apparatus for an internal combustion engine according to the tenth aspect, the rotation speed of the electric fan is changed based on the specified combustion state.

According to a thirteenth aspect of the present invention, there is provided a cooling water control device for an internal combustion engine according to any one of the tenth to twelfth aspects, further comprising means for storing an engine cooling water temperature rise determination value in advance for a predetermined time. Calculate the amount of change in the engine cooling water temperature during a predetermined time of the engine cooling water temperature from the previously detected cooling water temperature and the current cooling water temperature, and when the amount of change in the engine cooling water temperature is smaller than the engine cooling water temperature rise determination value, This is to change the rotation start water temperature of the electric fan to a high temperature side.

According to a fourteenth aspect of the present invention, in the cooling water control device for an internal combustion engine according to the thirteenth aspect, when the engine cooling water temperature change amount is smaller than the engine cooling water temperature rise determination value, the rotation of the electric fan is controlled. The number is changed to a low rotation side or stopped.

According to a fifteenth aspect of the present invention, in the cooling water control device for an internal combustion engine according to the thirteenth aspect, when the engine cooling water temperature is equal to or lower than a predetermined temperature, First, the rotation speed of the electric fan is changed to a low rotation side or stopped.

According to a sixteenth aspect of the present invention, there is provided a cooling water control device for an internal combustion engine according to any one of the thirteenth to fifteenth aspects, wherein the deviation between the engine cooling water temperature change amount and the engine cooling water temperature rise determination value is determined. The number of revolutions of the electric fan is changed continuously.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of the present invention will be described. In order to solve the problem during engine warm-up operation, a conventional thermo-wax type bypass valve whose opening is mechanically determined by the temperature of the engine cooling water is abolished.
Setting the amount of cooling water when the bypass valve is fully opened (in a state where the radiator is not used) after the bypass valve is fully opened (in a state where the radiator is not used) after changing to a bypass valve that can electrically control the opening degree, which is a known technique as disclosed in Japanese Patent No. 9214. The opening is changed according to the combustion state of the engine, for example, the normal stoichiometric or lean combustion mode or the ultra-lean combustion mode by fuel injection during the engine compression stroke. By doing so, the warm-up time can be accelerated even when using the combustion mode in which the engine heat generation amount is small, and the control can be performed without overheating even when using the combustion mode in which the heat generation amount is large.

At this time, the opening of the engine cooling water is controlled by calculating the amount of increase in the engine cooling water temperature for a predetermined period in the control device and determining whether the temperature of the engine cooling water is increasing or decreasing based on the calculated value. In addition, by controlling the opening degree according to the deviation between the calculated engine cooling water temperature rise amount and a predetermined value for calculating the deviation of the rise amount (hereinafter, engine cooling water temperature rise judgment value), the engine can be more precisely controlled. Control of the cooling water temperature becomes possible.

Further, in addition to the above combination, even in a combustion state in which the maximum amount of heat is generated when the bypass valve is fully closed (a state in which the entire cooling water is recirculated to the radiator), cooling can be performed without driving the radiator electric fan or safety margin can be reduced. In addition, by using a radiator with a somewhat smaller capacity than usual, it is possible to control the cooling water temperature to some extent only by controlling the opening of the bypass valve even when the amount of heat generation is large, and as a result, the radiator electric fan Since the use frequency of the engine is reduced, the fuel efficiency of the engine can be improved. Note that the selection of the bypass side and the radiator side by opening and closing the bypass valve according to the present embodiment is an example, and can be freely configured by arrangement and the like.

Next, even with the problem that the temperature of the engine cooling water drops depending on the used combustion mode even after the completion of warming-up of the engine, the combustion mode in which the heat generation amount is small by the above-described method of controlling the bypass valve. In this case, it is possible to suppress the decrease by controlling the opening of the bypass valve to the open side.

As a concomitant measure for improving the engine fuel economy, in a combustion mode in which the amount of heat generated by the engine is small, the temperature of the cooling water for stopping the radiator electric fan is changed to a high temperature or the number of revolutions is controlled to a low rotation. This is also effective because the power consumption of the system can be suppressed and the load on the internal combustion engine can be reduced. At this time, the magnitude of the heat generation amount can be determined for each combustion mode or by the deviation between the engine cooling water temperature rise amount and the engine cooling water temperature rise determination value for the above-described predetermined period.

Further, when a deviation between the engine coolant temperature rise amount for a predetermined period and the engine coolant temperature rise determination value is used,
The cooling water temperature can be precisely controlled by changing the stop cooling water temperature of the radiator electric fan to a high temperature side or controlling the rotation speed to a low rotation side according to the deviation.

By performing the above-described control, the total amount of cooling water can be reduced as compared with the related art, without reducing the maximum cooling capacity as compared with the related art or without increasing the conventional cooling water amount. In addition, it is possible to reduce the time required for warming up the engine, and it is possible to improve performance such as exhaust gas and fuel efficiency.

Further, even in a situation where the combustion temperature is low depending on the engine speed, load, combustion mode and the like, and the engine cooling water temperature conventionally decreases, the amount of cooling water circulating through the radiator is changed to the transition of the engine cooling water temperature. Since it can be prevented in advance by limiting according to it, it becomes possible to improve the performance such as exhaust gas and fuel efficiency.

By applying the above control,
Even in the area where cooling by the radiator was conventionally assisted by the radiator electric fan, the maximum cooling capacity is over-specified.With this control, cooling with only the radiator is sufficient, so the frequency of using the load called the radiator electric fan is reduced. As a result, the fuel efficiency of the engine can be improved.

By performing the above control, it is possible to quickly raise the temperature of the cooling water of the internal combustion engine to the target temperature even in a predetermined engine state, and thereafter to appropriately control the target temperature. Exhaust gas and fuel efficiency can be improved as compared with the related art regardless of the use condition of the engine.

An embodiment of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing Embodiment 1 according to the present invention. In the figure, 1 is an internal combustion engine, 2 is a radiator, 3 is a cooling water passage, 4 is a cooling water pump, 5 is a bypass passage, 6 is a bypass valve, 7 is a control unit, 8 is a crank angle sensor, 9 is a water temperature sensor, 10 is a radiator electric fan, 11 is a heater blower, and 12 is an air flow sensor.

The internal combustion engine 1 performs cooling by transmitting heat loss due to combustion to engine cooling water, but a general internal combustion engine is provided with a radiator 2 for radiating this heat to the atmosphere. A cooling water passage 3 between the internal combustion engine 1 and the radiator 2
Are connected in a ring. The cooling water is forcibly circulated by a cooling water pump 4 driven by the internal combustion engine 1.

At this time, when the temperature of the engine cooling water is low, since the heat radiation by the radiator 2 is unnecessary, the bypass passage 5 for bypassing the radiator 2 and the radiator 2
A bypass valve 6 for shutting off the passage to the The bypass valve 6 is generally a mechanical valve using a thermosensitive material such as thermowax, but is driven by a motor which can be controlled electrically and arbitrarily in the present embodiment. Use a valve that is This bypass valve 6 is a control unit 7 controlled by a microcomputer.
It operates according to the command from. FIG. 2 shows the direction of the flow of the cooling water due to the opening / closing operation of the bypass valve 6.

The control unit 7 includes:
A crank angle sensor 8 for knowing the rotation speed of the internal combustion engine 1, a cooling water temperature sensor 9 for knowing the engine cooling water temperature, and an air flow sensor 12 for knowing the intake air amount of the internal combustion engine are connected. Of the internal combustion engine 1 by taking the signal of
Each state is detected. Note that the control unit 7 also controls the internal combustion engine 1 itself.

The radiator 2 is provided with a radiator electric fan 10 driven by an electric motor. The radiator 2 is driven when there is no running wind when the vehicle is stopped or when the internal combustion engine 1 has a large amount of heat radiation. The cooling water temperature is controlled within a certain range by assisting the heat radiation of the radiator 2. The radiator electric fan 10 also operates according to an instruction from the control unit 7.

Next, although the internal combustion engine 1 is mounted on a vehicle, the vehicle is usually provided with a heater blower 11 for warming the interior of the vehicle, which is provided with the temperature of the cooling water of the internal combustion engine 1. Is generally performed by exchanging heat with air in the vehicle compartment, and this is also adopted in the present embodiment.

Next, the operation will be described with reference to FIGS. The present embodiment is an example of a method of controlling the temperature of the engine cooling water by controlling the cooling water passage using a bypass valve.

First, as shown in FIG. 3, R100 is prepared, which is a routine executed every predetermined period. The processing in this routine is as follows.
W (n) is obtained, the deviation from the engine cooling water temperature TW (n-1) obtained at the previous time is obtained in step 102, and the engine cooling is stored in a predetermined storage area (RAM area) in the computer in step 103. The process is completed only by storing the temperature change amount TWTR.

Next, as shown in FIG. 4, a main routine R110 of this processing is prepared. Before executing the processing in this routine, an engine cooling water temperature rise determination value for comparing whether the amount of change in engine cooling water temperature is equal to or more than a predetermined amount is prepared in a storage area (ROM area) in the computer. The engine cooling water temperature rise determination value is three-dimensional map data based on parameters of the engine speed and the engine load, and is used for different modes having different combustion temperatures such as stoichiometric, intake stroke injection lean mode, and compression stroke injection lean mode. Prepare for In addition, since a different value is provided depending on whether or not the heater blower of the vehicle equipment operates, which directly affects the temperature of the engine cooling water, this value is also separately prepared.

That is, in this embodiment, the engine cooling water temperature rise determination map KTTWUS in the stoichiometric state and the map KTTWUSB when the heater blower is operating, the engine cooling water temperature rise determination map KTTWUL in the intake stroke injection lean state, and the heater blower operation A map KTTWULB at the time, an engine chilled water temperature rise determination map KTTWUAL in the compression stroke injection lean state, and a map KTTWUALB at the time of the heater blower operation are prepared.

In the present embodiment, all of the above are prepared. However, in practice, the map at the time of operating the heater blower is omitted, or a certain amount or gain is provided for each state based on the stoichiometric state map. Even if the offset is performed, the control accuracy is inferior, but substantially the same effect can be obtained.

Next, the actual control contents will be described in detail. In step S111, the current engine coolant temperature TW
(n) Check whether the value is equal to or greater than a predetermined value KTBBC. here
When TW (n) is lower than KWTBC, the process proceeds to step S112, in which the opening of the bypass valve is fully opened, the amount of cooling water for cooling the engine is reduced, and the circulation of cooling water to the radiator is prohibited.

If TW (n) is equal to or higher than KWTBC in step S111, the process proceeds to step S113. Step S1
In step 13, the combustion mode of the engine is inspected and assigned to each step from step S114 to S116 for each combustion mode. In steps S114 to S116, basically, only the clearing and setting of the flag are performed, and the non-applicable bit of the flag F101 indicating the current cooling water temperature control mode is cleared and the corresponding bit is set. This time, this flag is prepared in 1 byte (8 bits), upper 4 bits are for combustion mode judgment, lower 4
The bits were used as used for other decisions. That is,
Based on the state inspected in step S113, it is assumed that only one of the upper 4 bits of F101 is set.

Next, at step S117, the operation status of the heater blower of the vehicle is inspected, and the flow branches to either step S118 or step S119 according to the status. Step S118 is selected when the heater blower is activated, and sets a predetermined bit (the least significant bit is used this time) among the lower 4 bits of F101.
When the heater blower is not operated, step S119 is selected, and a predetermined bit of F101 is cleared. With the processing so far, it is possible to determine which of the six prepared engine chilled water temperature rise determination maps is to be currently selected simply by looking at F101.

Next, the process proceeds to step S120, and based on F101, a currently applicable engine cooling water temperature rise determination map is selected.
Searches the selected map based on the engine speed NE and the engine load LE obtained from the engine intake air amount or the engine intake pipe pressure or the accelerator opening, and determines the engine coolant temperature rise judgment value KWTU according to the current engine operating state. To get.

Next, the routine proceeds to step S121, in which the difference between the previously obtained engine coolant temperature change amount TWTR and the engine coolant temperature rise judgment value KWTU according to the current engine operating state, that is, the second engine coolant water Calculate the temperature change amount KTWR2. And step S
In 122, the calculated second
The currently required cooling water bypass valve target opening KTWBPO is obtained based on the KTWR2 calculated from the cooling water bypass valve target opening map KTTWBPO, which is two-dimensional table data using the engine cooling water temperature variation KTWR2 as a parameter. I do.

In the present embodiment, a plurality of engine cooling water temperature rise determination maps are prepared depending on the combustion mode and the presence or absence of the heater blower. The cooling water bypass valve target opening map prepared here is prepared. Almost the same effects can be obtained by preparing a plurality of units depending on the combustion mode and the presence or absence of the heater blower operation. Next, in step S123, the opening of the bypass valve is actually changed based on the target opening of the bypass valve KTWBPO.

As described above, according to the conventional configuration and control of the internal combustion engine having a plurality of combustion states under the same rotation and the same load state, in the case of the operating state in which the combustion temperature is low such as in the lean mode and the radiant heat to the cooling water is small. Even in a situation where the engine cooling water temperature drops below the stable cooling water temperature range of the internal combustion engine, the engine combustion mode, engine operating state, and water temperature change degree are monitored, and Thus, the control according to the present embodiment for restricting the reflux flow rate to the radiator section can prevent such a situation, and can enlarge the lean combustion region.

Also, since the bypass valve itself can be electrically controlled and the cooling water temperature can be precisely controlled by the control according to the present embodiment, the flow rate when the bypass valve is fully opened, that is, the flow rate bypassing the radiator is set to be small. As a result, the engine warm-up time can be reduced, and the exhaust gas and fuel efficiency can be improved. In addition, since the cooling water temperature can be controlled in a certain operation range only by controlling the bypass valve, the operation frequency of the radiator electric fan can be reduced as compared with the conventional case, so that the fuel consumption performance can be improved. .

Therefore, in the present embodiment, when the engine is warmed up, the temperature raising performance is improved by reducing the amount of engine cooling water when the bypass valve is fully opened, and there is a marginal cooling effect by the radiator when the bypass valve is fully closed, and the bypass is in between. By controlling the coolant temperature by controlling the valve opening, the coolant temperature control with better responsiveness and target temperature follow-up performance than before can be achieved, and as a result, the exhaust gas and fuel economy performance can be improved. . In addition to the above-described effects, a certain degree of temperature control can be performed only by controlling the degree of opening of the bypass valve, so that the frequency of use of the radiator fan is reduced. This effect can also improve fuel efficiency.

Embodiment 2 FIGS. 5 and 6 are flowcharts showing Embodiment 2 of the present invention. In the present embodiment, an example of a method for controlling the temperature of the engine cooling water by controlling the radiator electric fan is shown. The circuit configuration shown in FIG. 1 may be used as in the first embodiment.

First, as shown in FIG. 5, R200, which is a routine executed at predetermined intervals, is prepared. The processing in this routine is as follows.
W (n) is obtained, the deviation from the engine cooling water temperature TW (n-1) obtained at the previous time is obtained in step 202, and the engine cooling is stored in a predetermined storage area (RAM area) in the computer in step 203. The process is completed only by storing the temperature change amount TWTR.

Next, a main routine R210 of this processing is performed.
Prepare Before executing the processing in this routine, an engine cooling water temperature rise determination value for comparing whether the amount of change in engine cooling water temperature is equal to or more than a predetermined amount is prepared in a storage area (ROM area) in the computer. It should be noted that the engine cooling water temperature rise determination value is determined based on the engine speed and the engine load parameters.
It is prepared as dimensional map data, and is prepared for each mode having a different combustion temperature, such as a stoichiometric, an intake stroke injection lean mode, and a compression stroke injection lean mode. In addition, since a different value is provided depending on whether or not the heater blower of the vehicle equipment operates, which directly affects the temperature of the engine cooling water, this value is also separately prepared.

That is, in this embodiment, the engine cooling water temperature rise determination map KTTWUS in the stoichiometric state and the map KTTWUSB when the heater blower is operating, the engine cooling water temperature rise determination map KTTWUL in the intake stroke injection lean state, and the heater blower operation A map KTTWULB at the time, an engine chilled water temperature rise determination map KTTWUAL in the compression stroke injection lean state, and a map KTTWUALB at the time of the heater blower operation are prepared.

In the present embodiment, all of the above are prepared. However, in practice, the map at the time of operating the heater blower is omitted, or a certain amount or gain is provided for each state based on the stoichiometric state map. Even if the offset is performed, the control accuracy is inferior, but substantially the same effect can be obtained.

Next, the actual control contents will be described in detail with reference to FIG. In step S211, it is checked whether the current engine coolant temperature TW (n) is equal to or higher than a predetermined value KTWROF. If TW (n) is lower than KTWROF, the process proceeds to step S212, in which the drive of the radiator electric fan is stopped.

If TW (n) is equal to or higher than KTWROF in step S211, the process proceeds to step S213. Steps
In S213, the combustion mode of the engine is inspected, and the combustion mode is assigned to each of the steps S214 to S216 for each combustion mode.
In steps S214 to S216, basically, only the clearing and setting of the flag are performed. The non-relevant bits of the flag F101 indicating the current cooling water temperature control mode are cleared and the corresponding bits are set. This time, this flag is prepared in 1 byte (8 bits), the upper 4 bits are for combustion mode judgment,
The 4 bits were used as used for other decisions. In other words, based on the state inspected in step S213,
Only one of the four bits is set.

Next, in step S217, the operation status of the heater blower of the vehicle is checked, and the flow branches to either step S218 or step S219 according to the status. Step S218 is selected when the heater blower is activated, and sets a predetermined bit (the least significant bit is used this time) among the lower 4 bits of F101.
When the heater blower is not operating, step S219 is selected, and a predetermined bit of F101 is cleared. With the processing so far, it is possible to determine which of the six prepared engine chilled water temperature rise determination maps is to be currently selected simply by looking at F101.

Next, the process proceeds to step S220, where the engine cooling water temperature rise judgment map corresponding to the present condition is selected based on F101.
Searches the selected map based on the engine speed NE and the engine load LE obtained from the engine intake air amount or the engine intake pipe pressure or the accelerator opening, and determines the engine coolant temperature rise judgment value KWTU according to the current engine operating state. To get.

Next, the routine proceeds to step S221, in which the difference between the previously obtained engine coolant temperature change amount TWTR and the engine coolant temperature rise determination value KTWU according to the current engine operating state, that is, the second engine coolant water Calculate the temperature change amount KTWR2. And step S
In 222, the calculated second prepared in advance in the computer
The radiator electric fan control target rotation speed KTWR currently required based on the KTWR2 calculated from the radiator electric fan control target rotation speed map KTTWRFO which is two-dimensional table data using the engine cooling water temperature change amount KTWR2 as a parameter
Get FO.

In this embodiment, a plurality of engine cooling water temperature rise determination maps described above are prepared in accordance with the combustion mode and the presence or absence of the operation of the heater blower, but the radiator electric fan control target rotation speed prepared here is prepared. Even if a plurality of maps are prepared according to the combustion mode and the presence or absence of the heater blower operation, substantially the same effect can be obtained. Further, in the radiator electric fan control target rotation speed map, a value that basically stops when KTWR2 is a negative value, that is, when the cooling water temperature tends to decrease, is described. Next, in step S223, the radiator electric fan is actually driven based on the radiator electric fan control target rotation speed KTWRFO.

As described above, in the present embodiment, in the operating state where the combustion temperature is low and the radiant heat to the cooling water is small, such as in the lean mode, the radiator is changed according to the engine combustion mode, the engine operating state, and the degree of change in the water temperature. By changing the rotation speed and rotation start conditions of the electric fan, it is possible to precisely control the cooling water temperature, expand the lean combustion area,
Fuel efficiency can be improved.

In this embodiment, the rotation speed of the radiator electric fan is finely controlled by changing the engine cooling water temperature in addition to the engine combustion mode, the engine operation state, and the like. However, a certain effect can be obtained only by changing the control start water temperature of the radiator electric fan according to the calculated second engine coolant temperature change amount KTWR2. Further, more simply, a radiator electric fan target rotation speed map in which a parameter is set to an engine cooling water temperature for each engine combustion mode is prepared, and only switching according to the engine combustion mode has a considerable effect. Even if the rotation start water temperature is provided for each engine combustion mode, it is possible to improve the control of the engine cooling water temperature as compared with the related art without changing the rotation speed.

[0069]

As described above, according to the present invention, a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state are provided. The engine cooling water is radiated by a radiator, the heat radiation by the radiator is assisted by an electric fan, and the engine has a passage that bypasses a passage to the radiator when the engine cooling water temperature is equal to or lower than a predetermined temperature. A cooling water control device, comprising: a means for specifying an operating state such as an engine speed and a load state; a means for detecting a current cooling water temperature state; and a means for specifying a combustion mode of the engine. Since the amount of change in the engine cooling water temperature during a predetermined time period of the engine cooling water temperature is calculated from the cooling water temperature detected before the current time and the current cooling water temperature, lean operation is performed. It is possible to expand the baked region, there is an effect that the exhaust gases, improvement in fuel efficiency becomes possible.

Further, according to the present invention, a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state are provided.
The engine is cooled by a water cooling system, heat radiation of the engine cooling water is performed by a radiator, heat radiation by the radiator is assisted by an electric fan, and a passage is provided to bypass a passage to the radiator when the temperature of the engine cooling water is lower than a predetermined temperature. And
A cooling water control device for an internal combustion engine including a bypass valve capable of electrically adjusting a flow rate of the radiator and a bypass passage, and a unit that detects a state of a current cooling water temperature,
Means for specifying the combustion mode of the engine, and the opening degree of the bypass valve is controlled in accordance with the combustion mode of the engine and the detected coolant temperature, so that the engine warm-up time can be reduced. In addition, it is possible to improve exhaust gas and fuel consumption performance, and it is also possible to control the cooling water temperature in a certain operating range only by controlling the bypass valve, and to reduce the operation frequency of the radiator electric fan compared to the conventional one. Since it is possible, the fuel efficiency can be further improved.

Further, according to the present invention, the engine has a plurality of combustion states having different combustion temperatures or different heat transfer rates to the engine cooling water at the same engine speed and the same load state, and the engine is cooled by the water cooling method. The heat radiation of the radiator is performed by a radiator, the heat radiation by the radiator is assisted by an electric fan, and when the engine cooling water temperature is equal to or lower than a predetermined temperature, a passage that bypasses a passage to the radiator is provided. A cooling water control device for an internal combustion engine having a bypass valve that can be automatically adjusted, comprising: means for detecting the current state of the cooling water temperature; and means for specifying the combustion mode of the engine. Since the rotation start water temperature and the number of rotations of the electric fan are changed on the basis of the above, it is possible to precisely control the cooling water temperature, and the lean combustion region Expansion Hakare, there is an effect that the exhaust gases, improvement in fuel efficiency becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a cooling water path by opening and closing a bypass valve according to the first embodiment of the present invention.

FIG. 3 is a flowchart for explaining an engine cooling water temperature control by controlling a bypass valve opening in the first embodiment of the present invention;

FIG. 4 is a flowchart for explaining an engine cooling water temperature control by controlling a bypass valve opening degree in the first embodiment of the present invention.

FIG. 5 is a flowchart for explaining engine cooling water temperature control by controlling the rotation speed of a radiator electric fan according to Embodiment 2 of the present invention;

FIG. 6 is a flowchart for explaining an engine cooling water temperature control by controlling a rotation speed of a radiator electric fan according to a second embodiment of the present invention.

[Explanation of symbols]

1 internal combustion engine, 2 radiator, 3 cooling water passage,
4 Cooling water pump, 5 bypass passage, 6 bypass valve, 7 control unit, 8 crank angle sensor, 9 water temperature sensor, 10 radiator electric fan, 11 heater blower, 12 air flow sensor.

Continued on the front page F term (reference) 3G084 AA04 BA09 BA15 DA02 DA10 EA04 EA11 EB08 FA07 FA10 FA11 FA18 FA20 FA33 FA38 3G301 HA15 JA02 JA21 JA32 MA01 MA19 NA08 NC02 NE15 PA01Z PA07Z PA11Z PA17Z PE01Z PE03Z PE08Z PF03Z

Claims (16)

[Claims] 1. An engine having a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state, cooling the engine by a water cooling system, and dissipating heat of the engine cooling water by a radiator. Do
A cooling water control device for an internal combustion engine, wherein the heat radiation by the radiator is assisted by an electric fan and a passage that bypasses a passage to the radiator when an engine cooling water temperature is equal to or lower than a predetermined temperature. A means for specifying an operating state such as a state, a means for detecting a state of a current cooling water temperature, and a means for specifying a combustion mode of an engine. A cooling water control device for an internal combustion engine, wherein an amount of change in engine cooling water temperature during a predetermined time of the engine cooling water temperature is calculated. And means for preliminarily storing an engine cooling water temperature rise judgment value, comparing the engine cooling water temperature rise judgment value with the engine cooling water temperature change amount, and comparing the engine cooling water temperature change amount for a predetermined period. 2. The cooling water control device for an internal combustion engine according to claim 1, wherein the increase amount is detected to be equal to or more than a predetermined amount. 3. The rotational speed of the internal combustion engine, the throttle opening,
3. The internal combustion engine according to claim 2, wherein the engine cooling water temperature rise determination value is changed based on two values of an engine load obtained from at least one of an intake air amount and an intake pipe pressure. Cooling water control device. 4. The cooling water control device for an internal combustion engine according to claim 2, wherein the engine cooling water temperature rise determination value is changed based on a combustion state of the internal combustion engine. 5. The engine cooling water temperature rise determination value is changed according to whether or not a vehicle interior heater blower mounted on a vehicle equipped with an internal combustion engine is operating.
5. The cooling water control device for an internal combustion engine according to any one of 4. 6. The engine has a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water under the same engine speed and the same load state, cools the engine by a water cooling system, and releases heat of the engine cooling water by a radiator. Do
A bypass valve that assists heat release by the radiator with an electric fan and has a passage that bypasses a passage to the radiator when the engine cooling water temperature is equal to or lower than a predetermined temperature, and that can electrically adjust a flow rate of the radiator and the bypass passage; A cooling water control device for an internal combustion engine, comprising: means for detecting the current state of the cooling water temperature; and means for specifying the combustion mode of the engine, wherein the means is provided in accordance with the combustion mode of the engine and the detected cooling water temperature. And controlling the opening of said bypass valve. 7. An engine cooling water temperature change amount in a predetermined time of the engine cooling water temperature from a cooling water temperature detected a predetermined time ago and a current cooling water temperature, the engine cooling water temperature determining means being provided in advance for storing an engine cooling water temperature rise determination value. 7. The cooling water control for an internal combustion engine according to claim 6, wherein when the engine cooling water temperature change amount is smaller than the engine cooling water rise determination value, the bypass valve is opened to bypass the radiator. apparatus. 8. The radiator according to claim 7, wherein when the engine coolant temperature is equal to or lower than a predetermined temperature, the radiator is bypassed by opening the bypass valve regardless of the value of the engine coolant temperature change amount. Cooling water control device for an internal combustion engine. 9. The flow rate distribution between the radiator and the bypass passage is adjusted by controlling an opening degree of the bypass valve according to a deviation between the engine coolant temperature change amount and the engine coolant temperature rise determination value. The cooling water control device for an internal combustion engine according to claim 7 or 8, wherein: 10. The engine has a plurality of combustion states having different combustion temperatures or different heat transfer coefficients with respect to engine cooling water at the same engine speed and the same load state, cools the engine by a water cooling method, and radiates engine cooling water by a radiator. ,
A bypass valve that assists heat release by the radiator with an electric fan and has a passage that bypasses a passage to the radiator when the engine cooling water temperature is equal to or lower than a predetermined temperature, and that can electrically adjust a flow rate of the radiator and the bypass passage; A cooling water control device for an internal combustion engine, comprising: means for detecting a current cooling water temperature state; and means for specifying a combustion mode of the engine, and operating the electric fan based on the specified combustion state. A cooling water control device for an internal combustion engine, wherein 11. The cooling water control device for an internal combustion engine according to claim 10, wherein the rotation start water temperature of the electric fan is changed based on the specified combustion state. 12. The system according to claim 1, wherein the number of revolutions of the electric fan is changed based on the specified combustion state.
0. The cooling water control device for an internal combustion engine according to 0. 13. An engine cooling water temperature change amount for a predetermined time of an engine cooling water temperature from a cooling water temperature detected a predetermined time ago and a current cooling water temperature, comprising means for storing an engine cooling water temperature rise determination value in advance. Calculating the engine cooling water temperature change amount, and when the engine cooling water temperature change amount is smaller than the engine cooling water temperature rise determination value, changing the rotation start water temperature of the electric fan to a higher temperature side. A cooling water control device for an internal combustion engine according to claim 1. 14. The internal combustion engine according to claim 13, wherein when the engine cooling water temperature change amount is smaller than the engine cooling water temperature rise determination value, the rotation speed of the electric fan is changed to a low rotation side or stopped. Engine cooling water control device. 15. When the engine cooling water temperature is equal to or lower than a predetermined temperature, the rotation speed of the electric fan is changed to a low rotation side or stopped regardless of the value of the engine cooling water temperature change amount. The cooling water control device for an internal combustion engine according to claim 13. 16. The rotation speed of the electric fan is continuously changed based on a deviation between the engine coolant temperature change amount and the engine coolant temperature rise determination value.
15. The cooling water control device for an internal combustion engine according to any one of 15.