CN114270022A - Cooling device for engine - Google Patents
Cooling device for engine Download PDFInfo
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- CN114270022A CN114270022A CN201980099679.5A CN201980099679A CN114270022A CN 114270022 A CN114270022 A CN 114270022A CN 201980099679 A CN201980099679 A CN 201980099679A CN 114270022 A CN114270022 A CN 114270022A
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- 238000001816 cooling Methods 0.000 title claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 175
- 239000000498 cooling water Substances 0.000 claims abstract description 40
- 230000008859 change Effects 0.000 claims abstract description 7
- 238000001514 detection method Methods 0.000 claims abstract description 7
- 230000004044 response Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 abstract description 11
- 101150109938 tgtA gene Proteins 0.000 description 23
- 230000007423 decrease Effects 0.000 description 8
- 239000000446 fuel Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 238000012545 processing Methods 0.000 description 8
- 239000002826 coolant Substances 0.000 description 5
- 238000012937 correction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000008016 vaporization Effects 0.000 description 3
- 238000009834 vaporization Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P3/00—Liquid cooling
- F01P3/20—Cooling circuits not specific to a single part of engine or machine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/14—Controlling of coolant flow the coolant being liquid
- F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
- F01P7/165—Controlling of coolant flow the coolant being liquid by thermostatic control characterised by systems with two or more loops
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/08—Temperature
- F01P2025/32—Engine outcoming fluid temperature
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/08—Temperature
- F01P2025/36—Heat exchanger mixed fluid temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/08—Temperature
- F01P2025/50—Temperature using two or more temperature sensors
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Temperature-Responsive Valves (AREA)
Abstract
The method comprises the following steps: a flow rate adjustment unit (12) that adjusts the flow rate of cooling water that circulates between the engine (1) and the radiator (9); a water temperature detection unit (17) that detects the temperature of cooling water flowing through the engine; a water temperature detection unit (21) that calculates a target water temperature of the cooling water; a deviation calculation unit (22) that calculates a water temperature deviation based on the water temperature and the target water temperature; a target opening calculation unit (24) that calculates a target opening of the flow rate adjustment unit (12) for achieving the target water temperature on the basis of the water temperature deviation; an opening/closing direction determination unit (25) that determines the opening/closing direction of the flow rate adjustment unit (12) on the basis of the state of change in the target opening degree; a control speed calculation unit (26) that calculates the control speed of the flow rate adjustment unit (12) on the basis of the water temperature deviation, and that calculates a control speed that is higher than the control speed when the opening/closing direction of the flow rate adjustment unit (12) is the closed side; and a valve control unit (27) that controls the opening of the flow rate adjustment unit (12) on the basis of the target opening and the control speed.
Description
Technical Field
The present invention relates to a cooling device for an engine.
Background
In this conventional cooling device, a thermostat is provided in a cooling water path connecting an engine and a radiator, and the thermostat has the following characteristics: the wax is gradually opened and closed between fully opened and fully closed in a temperature range of, for example, about 80 to 90 ℃ by thermal expansion of the wax. The circulation state of the cooling water between the engine and the radiator is adjusted according to the opening and closing of the thermostat, and the engine is kept in a predetermined temperature range.
On the other hand, in view of the recent demand for more careful water temperature control in order to meet the recent requirements for exhaust gas control, fuel efficiency improvement, and the like, an electronically controlled engine cooling device described in patent document 1, for example, has been put to practical use. The cooling device can adjust the flow rate of the cooling water flowing between the engine and the radiator by the flow path switching valve, and maintain the cooling water of the engine at the target water temperature by controlling the opening degree of the flow path switching valve based on, for example, a deviation between the target water temperature set based on the operating state of the engine and the water temperature detected by the water temperature sensor. In the electronic control type cooling device, since the opening/closing speed of the flow path switching valve with respect to the water temperature deviation can be arbitrarily set, for example, characteristics of a conventional thermostat are simulated, and characteristics of opening/closing the flow path switching valve with respect to the water temperature deviation are sometimes given.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2014-169661
Disclosure of Invention
Technical problem to be solved by the invention
However, in the cooling device of patent document 1, the temperature of the cooling water flowing through the engine greatly deviates from the target water temperature in the following situation.
As described above, the opening degree of the flow path switching valve is controlled based on the water temperature deviation, and the flow path switching valve is closed when the water temperature is less than or equal to the target water temperature, while the temperature is lowered by the open-side control of the flow path switching valve when the water temperature is greater than the target water temperature, for example. At this time, the cooling water circulates through the water jacket of the engine without being cooled by the radiator, and the water temperature T gradually rises as shown by a in fig. 4 by receiving heat from the engine. At this time, the cooling water is retained in the radiator and cooled by the traveling wind, and the temperature gradually decreases.
When the temperature of the cooling water increases and the water temperature T > the target water temperature tgtT as shown in B in fig. 4, the flow path switching valve is controlled to be opened. In the characteristic that the flow path switching valve is opened and closed relatively gently against the water temperature deviation, the opening control at this time is also performed relatively gently as shown in fig. 4C. However, since the low-temperature cooling water cooled in the radiator flows into the water cooling jacket, the water temperature T changes from rising to falling as shown by D in fig. 4, and rapidly decreases. The flow path switching valve is closed again in response to the reduction of the deviation of the water temperature accompanying the temperature reduction, but the closing side control at this time is also performed relatively slowly as indicated by the broken line Ea in fig. 4, so that the reduction of the cooling water temperature cannot be sufficiently suppressed, and the water temperature T deviates greatly from the target water temperature tgtT toward the low temperature side as indicated by the broken line Fa in fig. 4.
The above-described inappropriate cooling water temperature is lowered each time the flow path switching valve is switched, and the fuel efficiency and exhaust characteristics are deteriorated due to an increase in oil viscosity of the engine and vaporization failure of the fuel.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an engine cooling device capable of preventing a rapid decrease in the cooling water temperature when opening a flow path switching valve from closing and maintaining the engine in a good temperature range.
Technical scheme for solving technical problem
In order to achieve the above object, an engine cooling device according to the present invention includes: a flow rate adjustment unit that adjusts a flow rate of cooling water that circulates between the engine and the radiator; a water temperature detection unit that detects a temperature of cooling water flowing through the engine; a water temperature detection unit that calculates a target water temperature of the cooling water based on an operating state of the engine; a deviation calculating unit that calculates a water temperature deviation based on the water temperature detected by the water temperature detecting unit and the target water temperature calculated by the water temperature detecting unit; a target opening degree calculation unit that calculates a target opening degree of the flow rate adjustment unit for achieving the target water temperature, based on the water temperature deviation calculated by the deviation calculation unit; an opening/closing direction determination unit that determines the opening/closing direction of the flow rate adjustment unit based on the state of change in the target opening degree calculated by the target opening degree calculation unit; a control speed calculation unit that calculates a control speed of the flow rate adjustment unit based on the water temperature deviation calculated by the deviation calculation unit, and calculates a higher control speed than when the opening/closing direction determined by the opening/closing direction determination unit is on the open side when the opening/closing direction determined by the opening/closing direction determination unit is on the closed side; and a valve control unit that controls the opening degree of the flow rate adjustment unit based on the target opening degree calculated by the target opening degree calculation unit and the control speed calculated by the control speed calculation unit.
In another aspect, the water temperature control device may further include a first storage unit that stores a relationship between a preset water temperature deviation and a target opening degree, and the target opening degree calculation unit may calculate the target opening degree from the water temperature deviation based on the relationship stored in the first storage unit.
As another aspect, the water temperature control device may further include a water temperature deviation correction unit that calculates a corrected water temperature deviation based on at least a proportional term and an integral term of the basic water temperature deviation, using the water temperature deviation as a basic water temperature deviation, the first storage unit stores a relationship between the corrected water temperature deviation and a target opening, the target opening calculation unit calculates the target opening based on the corrected water temperature deviation, the opening/closing direction determination unit determines the opening/closing direction based on the target opening calculated based on the corrected water temperature deviation, the control speed calculation unit calculates the control speed based on the basic water temperature deviation, and the valve control unit controls the opening of the flow rate adjustment unit based on the target opening calculated based on the corrected water temperature deviation.
As another aspect, the control device may further include a second storage unit that stores a relationship between a preset water temperature deviation and an open-side control speed of the flow rate adjustment unit and an unlimited value that is a control speed equal to or higher than a response speed of the flow rate adjustment unit, wherein the control speed calculation unit may calculate the control speed from the water temperature deviation based on the relationship stored in the second storage unit when the open-close direction determined by the open-close direction determination unit is the open side, and may set the unlimited value stored in the second storage unit as the control speed regardless of the water temperature deviation when the determined open-close direction is the closed side.
Effects of the invention
According to the cooling device for an engine of the present invention, it is possible to prevent the temperature of the cooling water from rapidly decreasing when the flow path switching valve is controlled to be open from being closed, and to maintain the engine in a good temperature range.
Drawings
Fig. 1 is an overall configuration diagram illustrating an engine cooling device according to an embodiment.
Fig. 2 is a control block diagram showing the structure of the ECU.
Fig. 3 is a flowchart showing a water temperature control routine executed by the ECU.
Fig. 4 is a time chart comparing the control states of the cooling water temperature in the embodiment and the technique of patent document 1.
Detailed Description
Hereinafter, an embodiment of an engine cooling device embodying the present invention will be described.
The engine 1 of the present embodiment is mounted on a passenger car as a power source for running, and is cooled by a water-cooled cooling device 2. As shown in fig. 1, the cooling water discharged from the water pump 4 flows through a water jacket 3 formed in the engine 1, and then flows out from the water jacket 3 into an outflow passage 5 connected to one side of the engine 1. One ends of a main water passage 6, an auxiliary water passage 7, and a bypass water passage 8 are connected to the outflow passage 5, and the other end of the bypass water passage 8 is connected to the suction side of the water pump 4.
A radiator 9 is installed in the main water passage 6, and the other end of the main water passage 6 is connected to the suction side of the water pump 4. The auxiliary water passages 7 are branched into two branches, and an EGR valve 10 for circulating exhaust gas to the intake side and a throttle device 11 for adjusting the intake air amount are provided, and the other end of each auxiliary water passage 7 is connected to a portion of the main water passage 6 on the water pump 4 side of the radiator 9.
Therefore, the cooling water guided from the outflow passage 5 to the main water passage 6 is cooled by the traveling wind when flowing through the radiator 9, and the cooling water is returned to the water pump 4 while being cooled. The cooling water guided from the outflow passage 5 to the sub-water passage 7 flows through the EGR valve 10 and the throttle device 11, cools these devices 9 and 10, increases in temperature, and returns to the water pump 4. The coolant guided from the outflow passage 5 to the bypass water passage 8 is directly returned to the water pump 4 at that temperature.
A flow path switching valve 12 is disposed in the outflow path 5, and the flow path of the cooling water is continuously adjusted by the flow path switching valve 12. Specifically, an inlet port of the channel switching valve 12 communicates with the inside of the outflow channel 5, and an outlet port of the channel switching valve 12 communicates with the main water channel 6 and the sub water channel 7, respectively. The flow path switching valve 12 is configured to be of a rotary type in which a built-in rotor is rotated by driving of a motor 13. The opening ratio of the main water passage 6 and the sub water passage 7 is continuously adjusted according to the angle θ of the rotor, and thereby the flow rate of the cooling water guided from the outflow passage 5 to the main water passage 6 and the sub water passage 7 is changed.
In the following description, an opening area on the main water passage 6 side, in other words, the opening a of the radiator 9 is mainly used, and an adjustment state based on the opening ratio of the passage switching valve 12 is shown. For example, when the fully closed state of the main water passage 6 side is indicated as the radiator opening a being 0%, the flow of the cooling water to the radiator 9 is stopped. The fully opened state of the main water passage 6 side is represented as the radiator opening a being 100%, and the flow rate of the cooling water flowing through the radiator 9 is maximized at this time.
When the flow path of the cooling water is continuously adjusted in this way, as a result, the flow rate of the cooling water flowing between the engine 1 and the radiator 9 is adjusted, and therefore, in the present embodiment, the flow path switching valve 12 functions as a flow rate adjustment portion of the present invention.
The operating state of the cooling device 2 is controlled by an ECU15 (electronic control unit), and the ECU15 includes an input/output interface 15a, a storage device 15b (ROM, RAM, etc.) containing a plurality of control programs, a central processing unit 15c (cpu), a timer 15d, and the like. Various sensors such as a position sensor 16 for detecting the rotor angle of the flow path switching valve 12, a first water temperature sensor 17 for detecting the temperature of the coolant flowing out of the engine 1 into the outflow path 5 as the engine temperature T, and a second water temperature sensor 18 for detecting the temperature of the coolant after passing through the radiator 9 are connected to the input side of the ECU 15.
Various devices such as a motor 13 for driving the flow path switching valve 12 are connected to the output side of the ECU 15. In the present embodiment, the engine temperature T corresponds to the temperature of the cooling water flowing through the engine 1 of the present invention, and the first water temperature sensor 17 that detects the engine temperature T functions as a water temperature detecting unit of the present invention.
Next, the structure of the ECU15 will be described based on the control block diagram of fig. 2.
The target water temperature calculator 21 of the ECU15 calculates the target water temperature tgt of the coolant based on the operating state of the engine 1, and inputs the target water temperature tgt to the deviation calculator 22 together with the engine temperature T detected by the first water temperature sensor 17.
The deviation calculator 22 calculates a base water temperature deviation Δ Tbase as a difference between the target water temperature tgt and the engine temperature T, and inputs the calculated deviation Δ Tbase to the PI controller 23. The PI control calculates a corrected water temperature deviation Δ T by the PI control by setting a proportional term in the P term setting unit 23a of the PI control unit 23, setting an integral term in the I term setting unit 23b, and adding the feedback terms in the adding unit 23c, based on the basic water temperature deviation Δ Tbase.
In the present embodiment, the PI control unit 23 functions as a water temperature deviation correction unit according to the present invention. In addition, instead of the PI control, PD control or PID control may be provided, and the PI control unit 23 may be omitted and the basic water temperature deviation Δ Tbase may be treated as the corrected water temperature deviation Δ T.
The corrected water temperature deviation Δ T is input to the target opening calculation unit 24, and the target radiator opening tgtA is calculated based on the corrected water temperature deviation Δ T. For the above calculation processing, a control map that defines in advance the relationship between the corrected water temperature deviation Δ T and the target radiator opening tgtA is stored in the storage device 15b of the ECU 15. Table 1 below shows an example of the control map, and sets the characteristic in which the target radiator opening tgtA is increased as a whole together with an increase in the corrected water temperature deviation Δ T. For example, the target radiator opening tgtA is calculated to be 0% when the corrected water temperature deviation Δ T is 0 ℃, and the target radiator opening tgtA is calculated to be 100% when the corrected water temperature deviation Δ T is 10 ℃.
In the present embodiment, the storage device 15b storing the control map of table 1 functions as the first storage unit of the present invention.
[ Table 1]
(Table 1)
| ΔT(℃) | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| tgtA(％) | 0 | 0 | 1 | 3 | 6 | 13 | 22 | 34 | 51 | 73 | 100 |
The target radiator opening tgtA is input to the opening/closing direction determination unit 25, and the opening/closing direction determination unit 25 determines the direction of change of the target radiator opening tgtA, in other words, the opening/closing direction of the flow path switching valve 12, based on the deviation of the target radiator opening tgtA calculated in the current and previous control cycles. In the present embodiment, the deviation between the present value and the previous value of the target radiator opening tgtA corresponds to the state of change in the target opening of the present invention.
On the other hand, the determination result of the opening/closing direction determination unit 25 is input to the switching unit 26a of the control speed calculation unit 26 together with the basic water temperature deviation Δ Tbase calculated by the deviation calculation unit 22. The switching unit 26a switches to the opening-side speed calculation unit 26b when the determination result of the opening/closing direction determination unit 25 is on the opening side, and switches to the closing-side speed calculation unit 26c when the determination result is on the closing side. The base water temperature deviation Δ Tbase is input to the speed calculation units 26b and 26c on the side to which the switching is made, and the control speed θ spd of the flow path switching valve 12 is calculated based on the base water temperature deviation Δ Tbase.
For the above calculation processing, the storage device 15b of the ECU15 stores a control map in which the relationship between the basic water temperature deviation Δ Tbase and the control speed θ spd is predetermined in correspondence with each of the speed calculation units 26b and 26 c. Table 2 below shows an example of a control map applied to the open-side speed calculation unit 26b, and table 3 below shows an example of a control map applied to the closed-side speed calculation unit 26 c.
In the present embodiment, the storage device 15b storing the control maps of table 2 and table 2 functions as the second storage unit of the present invention.
[ Table 2]
(Table 2)
[ Table 3]
(Table 3)
As shown in table 2, when the passage switching valve 12 is controlled to be open, the higher the base water temperature deviation Δ Tbase, the higher the control speed θ spd is calculated. The mapping characteristics described above are based on the following insight: the more the engine temperature T deviates from the target water temperature tgt, the more rapid rotor angle control of the flow path switching valve 12 is required. However, the control speed θ spd to the open side set in table 2 is relatively low, and the flow path switching valve 12 is manufactured to have the following specifications: the controller has a response speed that can sufficiently follow the maximum control speed θ spd of 8 (%/second).
The following is a finding that the target radiator opening tgtA obtained from the corrected water temperature deviation Δ T is applied to the process of determining the opening/closing direction of the flow path switching valve 12 and the control of the radiator opening a described later, and the basic water temperature deviation Δ tbase is applied to the process of calculating the control speed θ spd. As described later, the actual radiator opening a and thus the rotor angle θ of the flow path switching valve 12 are feedback-controlled based on the target radiator opening tgtA. Therefore, by applying the target radiator opening tgtA based on the corrected water temperature deviation Δ T reflecting the PI control, it is possible to accurately control the radiator opening a and to accurately determine the opening/closing direction of the flow path switching valve 12 based on the rotor angle θ control.
On the other hand, the control speed θ spd needs to be controlled in accordance with the state of deviation of the engine temperature T from the target water temperature tgt at that time, as described above. Therefore, the flow path switching valve 12 can be driven at the appropriate control speed θ spd by setting the actual target water temperature tgtT based on the base water temperature deviation Δ Tbase, which is the deviation between the engine temperature T and the actual target water temperature tgtT, more preferably than the post-correction water temperature deviation Δ T including the delay element based on the I control.
On the other hand, as shown in table 3, when the passage switching valve 12 is controlled to the closed side, regardless of the magnitude of the base water temperature deviation Δ Tbase, the control speed θ spd, which is significantly higher than the control speed θ spd at the time of the open side control, is uniformly calculated to be 200 (%/sec). The control speed θ spd is a value equal to or higher than the response speed of the flow path switching valve 12 corresponding to the non-limiting value of the present invention, and the flow path switching valve 12 is inevitably driven at the maximum speed. The flow path switching valve 12 is driven on the closed side at the relatively high control speed θ spd as compared with the open side as described above in order to solve the problem carried by the technique of patent document 1, and details about this point will be described below based on the timing chart.
The control speed θ spd calculated by the opening-side speed calculation unit 26b or the closing-side speed calculation unit 26c of the control speed calculation unit 26 is input to the valve control unit 27 together with the target radiator opening tgtA calculated by the target opening calculation unit 24. Although not shown, the storage device 15b of the ECU15 stores a control map that defines the relationship between the radiator opening a and the rotor angle θ of the flow path switching valve 12, and the valve control unit 27 calculates the target rotor angle tgt θ from the target radiator opening tgtA with reference to the map. Further, based on the deviation between the target rotor angle tgt θ and the actual rotor angle θ detected by the position sensor 16, feedback control is performed while maintaining the opening/closing speed of the flow path switching valve 12 at the control speed θ spd.
Next, the control content of the ECU15 described above will be described based on the flowchart of fig. 3.
First, in step 1, detection information is read from each sensor, and in the next step 2, the basic water temperature deviation Δ Tbase is calculated, and in step 3, the corrected water temperature deviation Δ T is calculated. The process of step 2 is executed by the deviation calculation unit 22, and the process of step 3 is executed by the PI control unit 23. Then, the target radiator opening tgtA is calculated based on the control map of table 1 in step 4, and the direction of change of the target radiator opening tgtA is determined in step 5. The process of step 4 is executed by the target opening degree calculation unit 24, and the process of step 5 is executed by the opening/closing direction determination unit 25.
When the change direction determined in step 5 is on, the process proceeds from step 6 to step 7, and the on control speed θ spd is calculated based on the control map shown in table 2. When the changing direction is on the closed side, the process proceeds from step 6 to step 8, and the closed-side control speed θ spd is calculated based on the control map shown in table 3. Then, in step 9, the flow path switching valve 12 is feedback-controlled based on the target radiator opening tgtA and the control speed θ spd. The processing of step 6 is executed by the switching unit 26a of the control speed calculation unit 26, the processing of step 7 is executed by the open side speed calculation unit 26b, the processing of step 8 is executed by the close side speed calculation unit 26c, and the processing of step 10 is executed by the valve control unit 27.
Next, a control situation of the cooling water temperature based on the processing by the ECU15 will be described based on the time chart of fig. 4.
In the above-described drawings, the target water temperature tgt is shown to be kept constant for easy understanding, and for example, when the engine temperature T is equal to or lower than the target water temperature tgt, the target radiator opening tgtA is calculated to be 0% based on table 1, and the main water passage 6 side is fully closed by the passage switching valve 12. Therefore, the cooling water is circulated through the water jacket 3 of the engine 1 via the bypass water path 8 or the sub water path 7 without being cooled by the radiator 9, and the engine temperature T gradually rises by receiving heat from the engine 1 as shown by a in fig. 4. At this time, the cooling water is retained in the radiator 9, and the temperature is gradually lowered by cooling with the traveling wind.
When the engine temperature T > the target water temperature tgt as shown in fig. 4B due to the increase in the temperature of the coolant, the flow path switching valve 12 is controlled to be opened based on the target radiator opening tgtA calculated from table 1. The control speed θ spd of the flow path switching valve 12 at this time is set based on table 2, and the flow path switching valve 12 is controlled to be opened relatively slowly as shown in C in fig. 4. However, since the low-temperature cooling water cooled in the radiator 9 flows into the water jacket 3, the engine temperature T changes from rising to falling as shown by D in fig. 4, and rapidly decreases.
In response to the decrease in the corrected water temperature deviation Δ T accompanying the temperature decrease, the passage switching valve 12 is controlled to be closed based on the target radiator opening tgtA calculated from table 1. The control speed θ spd of the flow path switching valve 12 at this time is set based on table 3, and the flow path switching valve 12 is rapidly controlled to the closed side as shown by the solid line Eb in fig. 4. Therefore, the decrease in the engine temperature T is quickly suppressed, and the engine temperature T is changed to increase in a state not so far deviated from the target water temperature tgtT toward the low temperature side as shown by the solid line Fb in fig. 4. The decrease in the engine temperature T greatly deviating from the target water temperature tgtT causes an increase in oil viscosity and a vaporization failure of the fuel, and since it is possible to prevent such a situation from occurring and to keep the engine 1 in a good temperature range, the fuel efficiency and the exhaust gas characteristics thereof can be improved.
The significance of the cooling device of the engine 1 of the present embodiment can be understood as follows. In the first time electronic control type cooling devices were put into practical use, characteristics of opening and closing the flow path switching valve relatively slowly were often given in a manner similar to the characteristics of a thermostat. In addition, since importance is attached to prevention of overheating of the engine, it is considered that the control speed in the valve opening time should be increased in priority to the valve closing time of the flow path switching valve so as to suppress a rapid increase in the engine temperature T. However, which control characteristic does not avoid a sharp drop in the cooling water temperature as described based on fig. 4.
The above-described problem is caused by a phenomenon that the low-temperature cooling water in the radiator 9 flows into the water jacket 3 by the open-side control of the flow path switching valve 12, and in addition, the following original characteristics of the engine 1 are affected: the drop in water temperature due to cooling in the radiator 9 occurs more rapidly than the rise in water temperature due to heat received from the engine 1. On the other hand, in order to meet the recent requirements regarding fuel efficiency and exhaust characteristics, it is more important to prevent the engine 1 from being overcooled, which is a factor causing the increase in oil viscosity and the vaporization failure of the fuel, than to prevent the engine 1 from being overheated.
As is apparent from the above-described requirements for both the original characteristics of the engine 1 and the fuel efficiency and exhaust characteristics, cooling control is required to prevent the engine 1 from being overcooled with priority. The above-described requirement can be achieved by the cooling control in which the control speed θ spd when the valve is closed is made higher than when the flow path switching valve 12 is opened as in the present embodiment, and as a result, the above-described operational effects can be achieved.
On the other hand, the target opening degree calculation unit 24 calculates the target radiator opening degree tgtA from the corrected water temperature deviation Δ T based on the control map of table 1 stored in the storage device 15 b. Therefore, the feedback control of the rotor angle θ of the passage switching valve 12 is performed by reflecting the control map, in addition to the PI control based on the corrected water temperature deviation Δ T. For example, in the control map of table 1, the target radiator opening tgtA has a characteristic of rapidly increasing with respect to an increase in the corrected water temperature deviation Δ T, and therefore an increase in the engine temperature T can be reliably suppressed. Since the content of the feedback control can be arbitrarily changed based on the map characteristic as described above, the engine 1 can be maintained in a more favorable temperature region.
The embodiments have been described above, but the embodiments of the present invention are not limited to the above embodiments. For example, although the above embodiment is embodied as the cooling device 2 mounted on the engine 1 of the passenger vehicle, the present invention is not limited to this. For example, the cooling device may be embodied as an engine cooling device mounted on a motorcycle or an ATV (All Terrain Vehicle). The configuration of the water path of the cooling device 2 shown in fig. 1 is not limited to this, and can be arbitrarily changed.
(symbol description)
1 Engine
9 radiator
12 flow path switching valve (flow control part)
15b storage device (first storage unit, second storage unit)
17 first water temperature sensor (Water temperature detector)
21 target water temperature calculating part
22 deviation calculating part
23 PI controller (Water temperature deviation corrector)
24 target opening degree calculating part
25 opening/closing direction judging section
26 control speed calculating part
27 a valve control part.
Claims (4)
1. An engine cooling device, comprising:
a flow rate adjustment unit that adjusts a flow rate of cooling water that circulates between the engine and the radiator;
a water temperature detector that detects a temperature of the cooling water flowing through the engine;
a water temperature detector that calculates a target water temperature of the cooling water based on an operating state of the engine;
a deviation calculation unit that calculates a water temperature deviation based on the water temperature detected by the water temperature detection unit and the target water temperature calculated by the water temperature detection unit;
a target opening degree calculation unit that calculates a target opening degree of the flow rate adjustment unit for achieving the target water temperature, based on the water temperature deviation calculated by the deviation calculation unit;
an opening/closing direction determination unit that determines an opening/closing direction of the flow rate adjustment unit based on a change state of the target opening calculated by the target opening calculation unit;
a control speed calculation unit that calculates a control speed of the flow rate adjustment unit based on the water temperature deviation calculated by the deviation calculation unit, and calculates a higher control speed than when the opening/closing direction determined by the opening/closing direction determination unit is on the open side when the opening/closing direction determined by the opening/closing direction determination unit is on the closed side; and
a valve control unit that controls the opening degree of the flow rate adjustment unit based on the target opening degree calculated by the target opening degree calculation unit and the control speed calculated by the control speed calculation unit.
2. The engine cooling device according to claim 1,
further comprises a first storage unit for storing a relationship between a preset water temperature deviation and a target opening degree,
the target opening degree calculation unit calculates the target opening degree from the water temperature deviation based on the relationship stored in the first storage unit.
3. The engine cooling device according to claim 2,
further comprising a water temperature deviation correcting unit for calculating a corrected water temperature deviation based on at least a proportional term and an integral term of the basic water temperature deviation using the water temperature deviation as a basic water temperature deviation,
the first storage unit stores a relationship between the corrected water temperature deviation and the target opening degree,
the target opening degree calculating part calculates the target opening degree according to the corrected water temperature deviation,
the opening/closing direction determination unit determines the opening/closing direction based on the target opening calculated from the corrected water temperature deviation,
the control speed calculation unit calculates the control speed based on the basic water temperature deviation,
the valve control unit controls the opening degree of the flow rate adjustment unit based on a target opening degree calculated from the corrected water temperature deviation.
4. The cooling apparatus for an engine according to any one of claims 1 to 3,
a second storage unit for storing a relationship between a preset water temperature deviation and an open-side control speed of the flow rate adjustment unit and an unlimited value which is a control speed equal to or higher than a response speed of the flow rate adjustment unit,
the control speed calculation unit calculates the control speed from the water temperature deviation based on the relationship stored in the second storage unit when the opening/closing direction determined by the opening/closing direction determination unit is on the open side, and sets the unlimited value stored in the second storage unit as the control speed regardless of the water temperature deviation when the determined opening/closing direction is on the closed side.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2019/033823 WO2021038776A1 (en) | 2019-08-29 | 2019-08-29 | Engine cooling device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114270022A true CN114270022A (en) | 2022-04-01 |
| CN114270022B CN114270022B (en) | 2023-11-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980099679.5A Active CN114270022B (en) | 2019-08-29 | 2019-08-29 | Cooling device for engine |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP7259054B2 (en) |
| CN (1) | CN114270022B (en) |
| DE (1) | DE112019007670T5 (en) |
| WO (1) | WO2021038776A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113266457B (en) * | 2021-04-29 | 2022-07-12 | 广西玉柴机器股份有限公司 | Method and device for overheat protection of engine |
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|---|---|---|---|---|
| US4616599A (en) * | 1984-02-09 | 1986-10-14 | Mazda Motor Corporation | Cooling arrangement for water-cooled internal combustion engine |
| US20020195067A1 (en) * | 2001-06-21 | 2002-12-26 | Aisan Kogyo Kabushiki Kaisha | Engine cooling system |
| CN102345502A (en) * | 2010-07-30 | 2012-02-08 | 株式会社山田制作所 | Engine cooling apparatus |
| CN103814198A (en) * | 2011-09-22 | 2014-05-21 | 株式会社三国 | Coolant control valve apparatus |
| JP2016003578A (en) * | 2014-06-13 | 2016-01-12 | トヨタ自動車株式会社 | Engine cooling device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60169623A (en) * | 1984-02-14 | 1985-09-03 | Mazda Motor Corp | Cooling device for water-cooled engine |
| JP6154159B2 (en) | 2013-03-04 | 2017-06-28 | 株式会社ミクニ | Flow control device, flow control method |
| KR102518247B1 (en) * | 2016-07-18 | 2023-04-07 | 현대자동차주식회사 | Control method for flow control valve |
-
2019
- 2019-08-29 WO PCT/JP2019/033823 patent/WO2021038776A1/en active Application Filing
- 2019-08-29 CN CN201980099679.5A patent/CN114270022B/en active Active
- 2019-08-29 DE DE112019007670.1T patent/DE112019007670T5/en active Pending
- 2019-08-29 JP JP2021541887A patent/JP7259054B2/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4616599A (en) * | 1984-02-09 | 1986-10-14 | Mazda Motor Corporation | Cooling arrangement for water-cooled internal combustion engine |
| US20020195067A1 (en) * | 2001-06-21 | 2002-12-26 | Aisan Kogyo Kabushiki Kaisha | Engine cooling system |
| CN102345502A (en) * | 2010-07-30 | 2012-02-08 | 株式会社山田制作所 | Engine cooling apparatus |
| CN103814198A (en) * | 2011-09-22 | 2014-05-21 | 株式会社三国 | Coolant control valve apparatus |
| JP2016003578A (en) * | 2014-06-13 | 2016-01-12 | トヨタ自動車株式会社 | Engine cooling device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPWO2021038776A1 (en) | 2021-03-04 |
| CN114270022B (en) | 2023-11-21 |
| DE112019007670T5 (en) | 2022-05-12 |
| WO2021038776A1 (en) | 2021-03-04 |
| JP7259054B2 (en) | 2023-04-17 |
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