JP5655748B2 - Radiator cooling fan controller - Google Patents

Description

  The present invention is applied to an internal combustion engine capable of using a fuel in which gasoline and alcohol having a boiling point lower than that of the gasoline are used, and cooling the radiator for controlling an electric cooling fan provided in the radiator of the internal combustion engine. The present invention relates to a fan control device.

Conventionally, for example, an internal combustion engine that can use a fuel in which gasoline and ethanol are mixed is well known (see, for example, Patent Document 1).
The vehicle is provided with a radiator for cooling the engine cooling water. The cooling water flowing through the radiator is cooled by heat exchange with the traveling wind passing through the radiator.

  The vehicle is also provided with a cooling fan that blows air to the radiator. When a sufficient amount of traveling wind cannot be expected, such as when the vehicle is stopped or when traveling at a low speed, the cooling fan is driven to ensure the flow rate of air passing through the radiator.

JP 2010-1752 A

  By the way, when the vehicle stops in a state where the engine temperature is high, there is no traveling wind passing through the radiator, so that the cooling water is not cooled. Therefore, the engine temperature is kept high. When fuel supply systems such as delivery pipes and injectors are heated by heat transmitted from a high-temperature engine or radiated heat, the evaporation of ethanol, which has a lower boiling point than gasoline, is promoted, and liquid fuel Vapor is generated. As a result, when the engine is restarted, a phenomenon in which an amount of fuel commensurate with the engine operation state cannot be injected from the injector, that is, a so-called vapor lock phenomenon occurs, and the engine operation may become unstable.

  On the other hand, if the cooling fan is always driven when the engine is stopped, the instability of the engine operation at the time of restart can be suppressed. However, in this case, the cooling fan is driven until no vapor is generated, and there is a problem that the power of the battery for driving the cooling fan is wasted.

  These problems are not limited to internal combustion engines that can use a fuel that is a mixture of ethanol and gasoline with a boiling point higher than this, and fuel that is a mixture of other alcohol fuel and gasoline can be used. This can also occur in common in internal combustion engines.

  The present invention has been made in view of such circumstances, and its purpose is to appropriately suppress power consumption of a battery accompanying driving of a cooling fan while suitably suppressing instability of engine operation at the time of restart. An object of the present invention is to provide a cooling fan control device for a radiator that can be used.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
(1) The invention described in claim 1 is applied to an internal combustion engine capable of using a fuel in which gasoline and alcohol having a boiling point lower than that of the gasoline are used, and is an electric type provided in a radiator of the internal combustion engine. A cooling fan control device for a radiator that controls driving of a cooling fan , wherein when the fuel evaporation amount in the fuel tank after the fuel supply to the fuel tank is less than a predetermined amount, the alcohol concentration of the fuel is The cooling fan is driven after the engine is stopped assuming that the fuel concentration is higher than the predetermined concentration. On the other hand, when the fuel evaporation amount in the fuel tank after the refueling is equal to or higher than the predetermined amount, the alcohol concentration of the fuel is equal to or lower than the predetermined concentration. Therefore, the gist is to limit the driving of the cooling fan after the engine is stopped .

  In the case of a fuel in which gasoline and alcohol are mixed, since the boiling point of alcohol is lower than that of gasoline, the higher the alcohol concentration in the range where the alcohol concentration of the fuel is lower than the predetermined concentration, the boiling point of the fuel becomes lower. Lower. And the lower the boiling point of the fuel, the more likely it is that the temperature of the fuel in the fuel supply system such as an injector exceeds the boiling point of the fuel, and the evaporation of the alcohol contained in the fuel is promoted. Vapor is likely to occur.

Moreover, when the temperature of the fuel stored in the fuel tank rises as the outside air temperature rises or the engine operation continues, alcohol having a low boiling point first evaporates. Therefore, as described above, when the amount of fuel evaporation in the fuel tank after the fuel supply to the fuel tank is less than a predetermined amount, the alcohol evaporated from the fuel stored in the fuel tank is reduced. It can be considered that the alcohol concentration of the fuel is higher than the predetermined concentration because the amount of the alcohol is small and the fuel contains a large amount of alcohol.
On the other hand, when the amount of fuel evaporation in the fuel tank after the fuel is supplied to the fuel tank is equal to or greater than the predetermined amount, a large amount of alcohol is evaporated from the fuel stored in the fuel tank. It can be considered that the alcohol concentration of the fuel is not more than the predetermined concentration, assuming that the fuel does not contain much alcohol. Therefore, it is possible to indirectly grasp the alcohol concentration of the fuel stored in the fuel tank based on the fuel evaporation amount in the fuel tank after the fuel is supplied to the fuel tank. .
Then, with the above configuration, sometimes the alcohol concentration of fuel is higher than the predetermined concentration, it is the temperature of the fuel in the fuel supply system after the engine stop is above the boiling point of the fuel, vapor to the liquid fuel The cooling fan is driven because there is a risk of occurrence. Thereby, the generation of vapor in the liquid fuel can be suppressed by cooling the fuel. For this reason, it is possible to suitably suppress the occurrence of a vapor lock phenomenon during the subsequent engine restart and the inability to perform fuel injection.

On the other hand, sometimes the alcohol concentration of the fuel is to be less than the predetermined concentration, the liquid not exceed the boiling point of the fuel even if the temperature of the fuel in the fuel supply system becomes maximum temperature that can be reached after the engine is stopped The driving of the cooling fan is limited because there is no risk of vapor being generated in the fuel. Thereby, it can suppress suitably that a cooling fan is driven vainly until vapor does not generate | occur | produce in liquid fuel, and the power consumption of the battery accompanying the drive of a cooling fan can be suppressed suitably.

Therefore, it is possible to appropriately suppress power consumption of the battery accompanying driving of the cooling fan while suitably suppressing instability of engine operation at the time of restart.
(2) The radiator cooling fan control device according to claim 1 is configured to drive the cooling fan after the engine is stopped when the alcohol concentration of the fuel is equal to or lower than the predetermined concentration. It is preferable to embody with the aspect of prohibiting.

( 3 ) In the radiator cooling fan control device according to claim 1 or 2 , as in the invention according to claim 3 , the internal combustion engine introduces the evaporated fuel in the fuel tank into the intake passage for processing. An evaporative fuel treatment device is provided, and calculates a purge amount integrated value that is an integrated value of the evaporated fuel amount introduced into the intake passage after the fueling is performed, and the purge amount integrated value is less than a predetermined value In this case, the alcohol concentration of the fuel is higher than the predetermined concentration, and the cooling fan is driven after the engine is stopped. On the other hand, when the purge amount integrated value is equal to or higher than the predetermined value, the alcohol concentration of the fuel is lower than the predetermined concentration. As a specific example, the embodiment can be embodied in such a manner that the driving of the cooling fan is restricted after the engine is stopped. In this case, the evaporation amount of the fuel in the fuel tank after refueling can be accurately grasped from the purge amount integrated value. Accordingly, the alcohol concentration of the fuel can be accurately grasped based on the purge amount integrated value.

( 4 ) In the apparatus provided with the estimating means for estimating the alcohol concentration of the fuel, the alcohol concentration of the fuel estimated by the estimating means is equal to or less than the predetermined concentration as in the invention according to claim 4. In this case, it is desirable that the embodiment is embodied in such a manner that the driving of the cooling fan after the engine is stopped is limited regardless of the amount of fuel evaporated in the fuel tank after the fuel is supplied to the fuel tank. In this case, the alcohol concentration of the fuel can be grasped without grasping the evaporation amount of the fuel in the fuel tank after refueling. For this reason, it is possible to accurately avoid an increase in calculation load associated with the calculation of the evaporation amount.

( 5 ) The invention according to claim 5 is applied to an internal combustion engine capable of using a fuel in which gasoline and an alcohol having a boiling point lower than that of the gasoline are used, and is an electric cooling provided in a radiator of the internal combustion engine. A cooling fan control device for a radiator that controls driving of a fan, wherein the cooling fan after the engine is stopped when the amount of alcohol evaporated in the fuel in the fuel tank after the fuel is supplied to the fuel tank is less than a predetermined amount On the other hand, the gist is to limit the driving of the cooling fan after the engine is stopped when the amount of evaporation of the alcohol after the refueling is greater than the predetermined amount.

  When the temperature of the fuel stored in the fuel tank rises as the outside air temperature rises or the engine continues, alcohol having a low boiling point first evaporates. Therefore, the alcohol concentration of the fuel decreases as the alcohol evaporates from the fuel stored in the fuel tank, and the boiling point of the fuel increases.

  According to the above configuration, whether or not to drive the cooling fan is determined based on the amount of fuel evaporated in the fuel tank. Therefore, it is possible to appropriately suppress power consumption of the battery accompanying driving of the cooling fan while suitably suppressing instability of engine operation at the time of restart.

( 6 ) The invention according to claim 6 is applied to an internal combustion engine capable of using a fuel in which gasoline and an alcohol having a boiling point lower than that of the gasoline are used, and is electrically driven cooling provided in a radiator of the internal combustion engine. A cooling fan control device for a radiator that controls the driving of a fan, wherein the cooling fan is driven after the engine is stopped until the predetermined period has elapsed after the fuel is supplied to the fuel tank, while the fuel supply is performed. The gist is to limit the driving of the cooling fan after the engine is stopped after the predetermined period has elapsed.

  When the temperature of the fuel stored in the fuel tank rises as the outside air temperature rises or the engine continues, alcohol having a low boiling point first evaporates. Moreover, the alcohol concentration of the fuel decreases as the alcohol evaporates from the fuel stored in the fuel tank, and the boiling point of the fuel increases. Further, the longer the elapsed time since the fuel is supplied to the fuel tank, the more alcohol is evaporated from the fuel stored in the fuel tank.

  According to the above configuration, whether or not to drive the cooling fan is determined based on the elapsed time since the fuel is supplied to the fuel tank. Therefore, it is possible to appropriately suppress power consumption of the battery accompanying driving of the cooling fan while suitably suppressing instability of engine operation at the time of restart.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows schematic structure of the vehicle-mounted internal combustion engine to which the apparatus is applied about the cooling fan control apparatus of the radiator which concerns on one Embodiment of this invention. The graph which shows the relationship between the ethanol concentration of a fuel, and the boiling point of the said fuel. The timing chart which shows transition of ethanol concentration of fuel and boiling point of fuel together. The flowchart which shows the process sequence of the drive control of the cooling fan at the time of the engine stop of the embodiment. 7 is a flowchart showing a procedure for setting a drive prohibition flag in the embodiment.

Hereinafter, an embodiment in which a radiator cooling fan control device according to the present invention is embodied will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of an in-vehicle internal combustion engine (hereinafter, internal combustion engine 1) to which the present invention is applied. The vehicle is a hybrid car having both an internal combustion engine 1 and a motor as a drive source, and the internal combustion engine 1 is a port injection type engine that can use a mixed fuel of gasoline and ethanol having a boiling point lower than gasoline as a fuel. is there.

As shown in FIG. 1, the internal combustion engine 1 is provided with an intake passage 2 for introducing intake air into the combustion chamber 11 and an exhaust passage 3 for discharging exhaust gas from the combustion chamber 11.
In the intake passage 2, an air cleaner 21, a throttle valve 22, and a surge tank 24 are provided in order from the intake upstream side. A throttle motor 23 that opens and closes the throttle valve 22 is provided.

  The fuel in the fuel tank 41 is sucked by the fuel pump 42 and is pumped through the fuel supply passage 43 to be supplied to the injector 44. Further, fuel is injected from the injector 44 provided at the intake port toward the combustion chamber 11. A fuel supply system 4 is configured by the fuel tank 41, the fuel pump 42, the fuel supply passage 43, and the injector 44.

In addition, the internal combustion engine 1 is provided with a spark plug 12 that ignites an air-fuel mixture of fuel injected from the injector 44 and intake air.
The vehicle is provided with a cooling device 5 for cooling the internal combustion engine 1. The cooling device 5 cools the internal combustion engine 1 by pumping the cooling water discharged from the water pump 52 to a water jacket 53 formed in the cylinder block and the cylinder head. The cooling water discharged from the water jacket 53 is introduced into the radiator 54 through the cooling water passage 51. The cooling water is cooled by exchanging heat with the traveling wind passing through the radiator 54 when flowing through the radiator 54. The vehicle is provided with an electric cooling fan 55 that blows air to the radiator 54.

  The internal combustion engine 1 is provided with an evaporative fuel processing device 6 that introduces evaporative fuel generated in the fuel tank 41 into the intake passage 2 for processing. The evaporative fuel processing apparatus 6 includes a canister 61 having an adsorbent that adsorbs fuel components. The canister 61 is connected to the fuel tank 41 via the vapor passage 62. An open passage 64 is connected to the canister 61. As a result, the fuel component of the gas guided from the fuel tank 41 to the canister 61 through the vapor passage 62 is adsorbed by the canister 61 and purified. Then, the purified air is released into the atmosphere through the open passage 64.

  Further, the canister 61 is provided with a purge passage 63 communicated with the intake passage 2. An electric control valve 65 is provided in the middle of the purge passage 63. In such a fuel vapor processing apparatus 6, when the control valve 65 is opened, the air in the canister 61 is sucked into the intake passage 2 through the purge passage 63 by the negative pressure in the intake passage 2. At this time, the fresh air is introduced from the open passage 64 so that the fuel component adsorbed on the canister 61 is desorbed, and the fresh air and the fuel component are mixed to become a purge gas. This purge gas is introduced into the intake passage 2. Will come to be. The so-called purge control in which the fuel component adsorbed on the canister 61 is desorbed and purge gas is introduced into the intake passage 2 to perform combustion processing is performed, so that the fuel component adsorption capacity of the canister 61 is restored. become.

Various controls of the internal combustion engine 1, opening control of the control valve 65, and drive control of the cooling fan 55 are performed by the electronic control unit 9.
The internal combustion engine 1 includes, for example, an engine speed sensor 91 that detects an engine speed NE, an intake air sensor 92 that detects an intake air GA, a throttle opening sensor 93 that detects a throttle opening TA, and a water temperature that detects a cooling water temperature THW. Various sensors for detecting the engine operating state are provided, such as a sensor 94 and an air-fuel ratio sensor 95 for detecting the air-fuel ratio AF of the exhaust. Various sensors such as a liquid level sensor 96 for detecting the liquid level L of the fuel in the fuel tank 41 and an IG switch 97 are provided. These various sensors are electrically connected to the electronic control device 9.

Further, the electronic control device 9 is electrically connected to various sensors for detecting a vehicle running state such as an accelerator operation amount ACCP, a brake depression amount B, and a vehicle speed V.
The electronic control unit 9 temporarily stores a central processing unit (CPU) that performs arithmetic processing related to various controls, a read-only memory (ROM) that stores various control programs and data, and results of arithmetic processing. It comprises a random access memory (RAM) for storing. The electronic control unit 9 reads the detection signals of the various sensors, executes various arithmetic processes, and comprehensively controls the vehicle (the internal combustion engine 1, the control valve 65, the cooling fan 55) based on the results.

  Specifically, when the IG switch 97 is turned on, the electronic control device 9 starts the engine by driving the starter motor to perform cranking and starting fuel injection control and ignition control. When the IG switch 97 is turned off, the fuel injection from the injector 44 is stopped and the engine operation is stopped.

The electronic control unit 9 performs air-fuel ratio feedback control for controlling the fuel injection amount so that the air-fuel ratio becomes the stoichiometric air-fuel ratio.
The electronic control device 9 performs purge control for adjusting the purge gas introduced into the intake passage 2 by adjusting the opening degree of the control valve 65.

  Here, the relationship between air-fuel ratio feedback control and purge control will be described. The air-fuel ratio feedback control is basically performed by feedback-controlling the fuel injection amount based on the output of the air-fuel ratio sensor 95 so as to keep the air-fuel ratio in the vicinity of the theoretical air-fuel ratio.

  However, when the purge gas containing the fuel component is introduced into the intake passage 2 through the purge control, the fuel contained in the purge gas is supplied to the combustion chamber 11 in addition to the fuel injected from the injector 44. The air-fuel ratio will shift. Therefore, in the air-fuel ratio feedback control, while the purge gas is being introduced by the purge control, the fuel injection amount reduction correction for reducing the fuel injection amount injected from the injector 44 by the amount of fuel contained in the purge gas is performed. Yes. The amount of fuel contained in the purge gas (hereinafter referred to as the purge amount PG) is calculated at predetermined intervals by the electronic control unit 9 based on the purge gas flow rate and the purge concentration D learned in a known manner during engine operation. Is done. Then, the reduction correction is performed based on the calculated amount of fuel. Incidentally, in this embodiment, the purge amount PG is calculated from the following equation (1).

PG = GA × R × D (1)
Here, the purge amount R is calculated by multiplying the intake amount GA by the purge ratio R, which is the ratio of the purge gas contained in the intake air, and the purge amount PG is calculated by further multiplying the purge concentration D.

  Further, the electronic control unit 9 drives the cooling fan 55 in order to ensure the flow rate of the air passing through the radiator 54 when a sufficient amount of traveling wind cannot be expected, such as when the vehicle is stopped or when traveling at a low speed. Take control.

  By the way, as described above, when the vehicle stops with the engine temperature being high, there is no traveling wind passing through the radiator 54, and the cooling water cannot be cooled, so that the engine temperature is kept high. Become. When the fuel supply system 4 such as the fuel supply passage 43 and the injector 44 is heated by the heat transmitted from the high-temperature engine or the radiated heat, the evaporation of ethanol having a lower boiling point than gasoline is promoted. Vapor is generated in the liquid fuel. As a result, when the internal combustion engine 1 is restarted, a phenomenon in which an amount of fuel commensurate with the engine operating state cannot be injected from the injector 44, that is, a so-called vapor lock phenomenon occurs, and the engine operation may become unstable.

  Therefore, in this embodiment, the occurrence of the above-described inconvenience is suppressed through drive control of the cooling fan described below. That is, the amount of evaporated fuel introduced into the intake passage 2 after the fuel is supplied to the fuel tank 41, that is, the purge amount PG, is calculated, and this integrated value (hereinafter, purge amount integrated value PGS) is calculated. . When the purge amount integrated value PGS is less than the predetermined value PGSth, the cooling fan 55 is driven after the engine is stopped. On the other hand, when the purge amount integrated value PGS is equal to or greater than the predetermined value PGSth, the driving of the cooling fan 55 after the engine is stopped is prohibited. To do.

Next, the reason for determining whether or not to drive the cooling fan 55 when the engine is stopped according to the purge amount integrated value PGS after the refueling is performed will be described.
FIG. 2 shows the relationship between the ethanol concentration E of the fuel and the boiling point Tbp of the fuel.

  As shown in FIG. 2, the boiling point of ethanol (about 78 ° C.) is lower than the boiling point of gasoline (120 ° C. in this embodiment). That is, when the ethanol concentration E of the fuel is 0%, the fuel boiling point Tbp is 120 ° C. In the range where the ethanol concentration E of the fuel is from 0% to about 20% (the maximum value of the ethanol concentration E of the fuel distributed in Japan), the boiling point Tbp of the fuel decreases as the ethanol concentration E of the fuel increases. Thus, when the ethanol concentration E of the fuel is 20%, the boiling point Tbp of the fuel is about 111.5 ° C. Incidentally, in the range where the ethanol concentration E of the fuel is higher than 20%, the boiling point Tbp of the fuel becomes higher as the ethanol concentration E of the fuel becomes higher. In FIG. 2, the maximum temperature Tmax (112 ° C. in the present embodiment) at which the fuel temperature in the fuel supply system 4 can reach after the engine is stopped is indicated by a one-dot chain line.

  Thus, in the range of the ethanol concentration E of the fuel shown in FIG. 2 (0% ≦ E ≦ 20%), when the ethanol concentration E of the fuel is equal to or higher than the predetermined concentration Eth, the boiling point Tbp of the fuel is the highest that can be reached. The temperature falls below Tmax. In this case, since the temperature of the fuel in the fuel supply system 4 may exceed the boiling point Tbp of the fuel after the engine is stopped, the ethanol contained in the fuel may evaporate.

  On the other hand, when the ethanol concentration E of the fuel is lower than the predetermined concentration Eth, the boiling point Tbp of the fuel exceeds the reachable maximum temperature Tmax. In this case, since the situation where the temperature of the fuel in the fuel supply system 4 exceeds the boiling point Tbp of the fuel cannot occur after the engine is stopped, ethanol contained in the fuel does not evaporate.

  Accordingly, when the fuel concentration in the fuel tank 41 is set to, for example, 20% by supplying the fuel to the fuel tank 41, and the temperature of the fuel starts to increase with the engine operation, the fuel boiling point Tbp. Further, the ethanol concentration E of the fuel changes as shown in FIG. 3, for example. That is, as shown in FIG. 3, when the elapsed time t of engine operation after the refueling reaches the first predetermined time t1, first, ethanol having a low boiling point starts to evaporate, so that the ethanol concentration E of the fuel gradually decreases. It becomes like this. Along with this, the boiling point Tbp of the fuel gradually increases from 111.5 ° C. Thereafter, when the second predetermined time t2 elapses, the ethanol concentration E of the fuel becomes equal to or lower than the predetermined concentration Eth, and the boiling point Tbp of the fuel becomes equal to or higher than the reachable maximum temperature Tmax.

  Here, the ethanol concentration E of the fuel correlates with the amount of fuel evaporated from the fuel stored in the fuel tank 41 after the fuel is supplied to the fuel tank 41. Further, as described above, the fuel amount evaporated from the fuel stored in the fuel tank 41 has a correlation with the integrated value of the purge amount PG (hereinafter referred to as the purge amount integrated value PGS) after the refueling. . Therefore, in this embodiment, it is determined whether or not to drive the cooling fan 55 when the engine is stopped according to the purge amount integrated value PGS.

  Next, with reference to FIG. 4, a specific processing procedure of cooling fan drive control when the engine is stopped will be described. Note that the series of processes shown in FIG. 4 is repeatedly executed at predetermined intervals during energization of the electronic control unit 9.

  As shown in FIG. 4, in this series of processing, first, in step S1, it is determined whether an engine stop command has been output. Here, it is determined that the engine stop command is output when the OFF operation of the IG switch 97 is detected. If it is not determined that the engine stop command has been output (step S1: “NO”), it is determined that it is not the execution timing of the cooling fan drive control, and this series of processes is temporarily terminated.

  On the other hand, if it is determined in step S1 that an engine stop command has been output (step S1: “YES”), the process proceeds to step S2, and then whether or not the drive prohibition flag F is “OFF”. Determine whether.

  Here, the procedure for setting the drive prohibition flag will be described with reference to FIG. The series of processes shown in FIG. 5 is repeatedly executed at predetermined intervals during engine operation. The drive prohibition flag F is initially set to “OFF”.

  As shown in FIG. 5, in this series of processing, first, in step S11, it is determined whether fuel refueling has been performed immediately before. Here, when the liquid level L of the fuel in the fuel tank 41 detected by the liquid level sensor 96 has not risen by a predetermined value or more than the value detected in the previous control cycle, the fuel supply is performed immediately before. Judge that it is not done. As a result, when it is determined that fuel refueling has been performed immediately before (step S11: “NO”), the process proceeds to step S12, where it is possible that the fuel ethanol concentration E has increased due to the refueling. Then, “0” is set to the purge amount integrated value PGS, and this series of processes is temporarily ended. In this case, it is necessary to drive the cooling fan 55 when the engine is stopped, and the drive prohibition flag F remains “OFF” and is not changed.

  On the other hand, if it is determined in step S11 that the fuel supply has not been performed immediately before (step S11: “YES”), the process proceeds to step S13, where the purge amount integrated value PGS is updated. Specifically, the purge amount PG introduced into the intake passage 2 between the previous control cycle and the current control cycle is calculated, and the purge amount PG is set to the purge amount integrated value PGS in the previous control cycle. By adding, a new purge amount integrated value PGS is obtained.

  When the purge amount integrated value PGS is updated in this way, the process proceeds to step S14, and it is determined whether or not the purge amount integrated value PGS updated in step S13 is equal to or greater than a predetermined value PGSth. Here, the predetermined value PGSth is a value set in advance through experiments and simulations, and is set as follows. That is, the predetermined value PGSth is obtained when the ethanol concentration E of the fuel reaches the predetermined concentration Eth as the ethanol evaporates from a state where the fuel tank 41 is filled with the fuel having the ethanol concentration E of 20%. Is set to the purge amount integrated value PGS.

  If the purge amount integrated value PGS is greater than or equal to the predetermined value PGSth in step S14 (step S14: “YES”), a large amount of ethanol has evaporated from the fuel in the fuel tank 41, resulting in the ethanol concentration of the fuel. Assuming that E becomes equal to or lower than the predetermined density Eth, next, the process proceeds to step S15, the drive prohibition flag F is set to “ON”, and this series of processing is once ended.

  On the other hand, if the purge amount integrated value PGS is less than the predetermined value PGSth in step S14 (step S14: "NO"), ethanol has not evaporated so much from the fuel in the fuel tank 41, and the ethanol concentration of the fuel Assuming that E is higher than the predetermined concentration Eth, this series of processes is temporarily terminated. In this case, it is necessary to drive the cooling fan 55 when the engine is stopped, and the drive prohibition flag F remains “OFF” and is not changed.

  As shown in FIG. 4, when the drive prohibition flag F is “OFF” in step S2, the process proceeds to step S3, and the cooling fan 55 is driven. Then, the process proceeds to step S5, and it is determined whether or not a drive stop condition for stopping the drive of the cooling fan 55 is satisfied. Specifically, it is determined that the drive stop condition is satisfied when the elapsed time from the start of driving of the cooling fan 55 reaches a predetermined time. Here, when the drive stop condition is not satisfied (step S5: “NO”), the cooling fan 55 is continuously driven, and this series of processes is temporarily ended.

  On the other hand, if the drive stop condition is satisfied in step S5 (step S5: “YES”), then the process proceeds to step S6, the drive of the cooling fan 55 is stopped, and this series of processing is temporarily performed. finish.

  If the drive prohibition flag F is “OFF” in step S2, the process proceeds to step S4, the drive of the cooling fan 55 is prohibited, and this series of processes is temporarily terminated.

Next, the operation of this embodiment will be described.
In the present embodiment, when a sufficient amount of traveling wind cannot be expected, such as when the vehicle is stopped or traveling at a low speed, the cooling fan 55 is driven to ensure the flow rate of the air passing through the radiator 54. .

  Further, the purge amount integrated value PGS after the fuel tank 41 is refueled is calculated. When the purge amount integrated value PGS is less than the predetermined value PGSth, there is a possibility that the ethanol concentration E of the fuel is higher than the predetermined concentration Eth, and the temperature of the fuel in the fuel supply system 4 after the engine is stopped The cooling fan 55 is driven after the engine is stopped because there is a possibility that the boiling point Tbp may be exceeded and vapor may be generated in the liquid fuel. Thereby, it can suppress that vapor | steam generate | occur | produces in liquid fuel, and it can suppress suitably that it becomes impossible to perform fuel injection by the vapor lock phenomenon at the time of engine restart after that.

  On the other hand, when the purge amount integrated value PGS is equal to or higher than the predetermined value PGSth, the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth, and becomes the maximum temperature Tmax at which the fuel temperature in the fuel supply system 4 can be reached after the engine is stopped. Even if it does not exceed the boiling point Tbp of the fuel, the driving of the cooling fan 55 is prohibited because there is no risk of vapor being generated in the liquid fuel. Thereby, it can suppress suitably that the cooling fan 55 is driven vainly until vapor does not generate | occur | produce in liquid fuel. For this reason, the power consumption of the battery accompanying the drive of the cooling fan 55 can be suitably suppressed.

The electronic control device 9 corresponds to a radiator cooling fan control device according to the present invention.
According to the cooling fan control device for a radiator according to the present embodiment described above, the following operational effects can be obtained.

  (1) The internal combustion engine 1 includes an evaporated fuel processing device 6 that introduces and processes the evaporated fuel in the fuel tank 41 into the intake passage 2. The electronic control device 9 is applied to the internal combustion engine 1 that can use a fuel in which ethanol and gasoline having a boiling point higher than that of ethanol are used, and is an electric cooling fan 55 provided in the radiator 54 of the internal combustion engine 1. Control the drive. The electronic control unit 9 calculates a purge amount integrated value PGS that is an integrated value of the evaporated fuel amount introduced into the intake passage 2 after the fuel is supplied to the fuel tank 41. Then, when the purge amount integrated value PGS is less than the predetermined value PGSth, the electronic control device 9 drives the cooling fan 55 after stopping the engine because the ethanol concentration E of the fuel may be higher than the predetermined concentration Eth. On the other hand, when the purge amount integrated value PGS is equal to or greater than the predetermined value PGSth, the electronic control unit 9 prohibits driving of the cooling fan 55 after the engine is stopped, assuming that the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth. According to such a configuration, it is possible to appropriately suppress power consumption of the battery accompanying driving of the cooling fan 55 while suitably suppressing instability of engine operation at the time of restart.

  The radiator cooling fan control device according to the present invention is not limited to the configuration exemplified in the above-described embodiment, and can be implemented as, for example, the following forms appropriately modified.

  In the above embodiment and its modifications, ethanol is exemplified as an example of an alcohol contained in fuel, but the alcohol according to the present invention is not limited to this, and any other alcohol having a lower boiling point than gasoline Can be substituted with alcohol.

  In the above embodiment, the amount of evaporated fuel in the fuel tank 41 after refueling is determined based on the purge amount integrated value PGS, but the present invention is not limited to this. Instead of the purge amount integrated value PGS or in addition to the purge amount integrated value PGS, the amount of evaporated fuel in the fuel tank 41 after refueling based on the transition of the following parameters after refueling is performed. That is, the ethanol concentration E of the fuel may be grasped. Examples of such parameters include at least one of outside air temperature, engine operation duration, and vehicle travel distance.

  In the above-described embodiment and its modification, the ethanol concentration E of the fuel is grasped from the amount of evaporated fuel in the fuel tank 41 after refueling. Instead, for example, the air-fuel ratio sensor 95 is used. The ethanol concentration E of the fuel may be estimated in a known manner based on the air-fuel ratio AF of the exhaust detected by the above. In this case, the air-fuel ratio sensor 95 and the electronic control unit 9 correspond to estimation means according to the present invention.

  In place of the above embodiment and its modification, the cooling fan 55 is driven after the engine is stopped until the predetermined period elapses after the fuel is supplied to the fuel tank 41, while the fuel is supplied. You may make it prohibit the drive of the cooling fan 55 after an engine stop after the predetermined period passes. In this case, for example, when refueling is performed, it is assumed that the fuel tank 41 is filled with fuel having an ethanol concentration E of 20%, and the fuel ethanol concentration E is determined from the refueling. The maximum value of the time required to reach the predetermined concentration Eth or less can be set in the predetermined period. Thereby, it becomes possible to reliably suppress instability of engine operation at the time of restart.

  However, in practice, even if the elapsed time from the refueling is the same, the mode of decrease in the ethanol concentration E of the fuel differs depending on the transition of the engine operating state, the transition of the outside air temperature, or the vehicle travel distance. Therefore, it is desirable to variably set the predetermined period based on at least one of the transitions of these parameters.

  As described in the above embodiment, when the ethanol concentration E of the fuel is equal to or less than the predetermined concentration Eth, it is desirable to prohibit the driving of the cooling fan 55 after the engine is stopped in order to reliably suppress the power consumption of the battery. However, the present invention is not limited to this. When the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth, the drive is limited by reducing the amount of current supplied to the cooling fan 55 as compared with the case where it is not. You may make it do.

  In the above-described embodiment and its modification, the ethanol concentration E of the fuel is indirectly grasped, but instead of this, a sensor that directly detects the ethanol concentration E of the fuel is provided, and The driving mode of the cooling fan 55 may be set according to the detection result.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Intake passage, 3 ... Exhaust passage, 4 ... Fuel supply system, 5 ... Cooling device, 6 ... Evaporative fuel processing device, 9 ... Electronic control device, 11 ... Combustion chamber, 12 ... Spark plug, 21 DESCRIPTION OF SYMBOLS ... Air cleaner, 22 ... Throttle valve, 23 ... Throttle motor, 24 ... Surge tank, 41 ... Fuel tank, 42 ... Fuel pump, 43 ... Fuel supply passage, 44 ... Injector, 51 ... Cooling water passage, 52 ... Water pump, 53 ... Water jacket, 54 ... Radiator, 55 ... Cooling fan, 61 ... Canister, 62 ... Vapor passage, 63 ... Purge passage, 64 ... Open passage, 65 ... Control valve, 91 ... Engine speed sensor, 92 ... Intake air amount sensor, 93 ... throttle opening sensor, 94 ... air-fuel ratio sensor, 95 ... water temperature sensor, 96 ... liquid level sensor, 97 ... IG switch.

Claims (6)

Cooling fan control of a radiator that is applied to an internal combustion engine capable of using a fuel in which gasoline and alcohol having a boiling point lower than that of the gasoline are used, and controls driving of an electric cooling fan provided in the radiator of the internal combustion engine A device,
When the amount of fuel evaporation in the fuel tank after the fuel supply to the fuel tank is less than a predetermined amount, the alcohol concentration of the fuel is higher than the predetermined concentration and the cooling fan is driven after the engine is stopped, When the evaporation amount of fuel in the fuel tank after refueling is equal to or greater than the predetermined amount, the driving of the cooling fan after the engine is stopped is limited on the assumption that the alcohol concentration of the fuel is equal to or lower than the predetermined concentration. Radiator cooling fan control device. In the radiator cooling fan control device according to claim 1,
A cooling fan control device for a radiator, wherein when the alcohol concentration of the fuel is equal to or lower than the predetermined concentration, driving of the cooling fan is prohibited after the engine is stopped. In the radiator cooling fan control device according to claim 1 or 2,
The internal combustion engine includes an evaporated fuel processing device that introduces and processes the evaporated fuel in the fuel tank into the intake passage,
A purge amount integrated value that is an integrated value of the evaporated fuel amount introduced into the intake passage after the refueling is calculated is calculated, and when the purge amount integrated value is less than a predetermined value, the alcohol concentration of the fuel is the predetermined concentration. The cooling fan is driven after the engine is stopped, and when the purge amount integrated value is not less than the predetermined value, the alcohol concentration of the fuel is not more than the predetermined concentration, and the driving of the cooling fan after the engine is stopped is limited. A cooling fan control device for a radiator. In the radiator cooling fan control device according to any one of claims 1 to 3 ,
An estimation means for estimating the alcohol concentration of the fuel;
When the alcohol concentration of the fuel estimated by the estimating means is equal to or lower than the predetermined concentration, after the engine is stopped regardless of the amount of fuel evaporated in the fuel tank after the fuel is supplied to the fuel tank. A cooling fan control device for a radiator, wherein the driving of the cooling fan is limited .   A cooling fan control device for a radiator that is applied to an internal combustion engine capable of using a fuel in which gasoline and alcohol having a boiling point lower than that of the gasoline are used, and controls driving of an electric cooling fan provided in the radiator of the internal combustion engine Because
  When the amount of alcohol evaporated in the fuel in the fuel tank after the fuel is supplied to the fuel tank is less than a predetermined amount, the cooling fan is driven after the engine is stopped, while the alcohol after the fuel is supplied When the evaporation amount is equal to or greater than the predetermined amount, the driving of the cooling fan after the engine is stopped is limited.
  A cooling fan control device for a radiator.   A cooling fan control device for a radiator that is applied to an internal combustion engine capable of using a fuel in which gasoline and alcohol having a boiling point lower than that of the gasoline are used, and controls driving of an electric cooling fan provided in the radiator of the internal combustion engine Because
  The cooling fan is driven after the engine is stopped until the predetermined period elapses after the fuel is supplied to the fuel tank, and the cooling fan after the engine is stopped after the predetermined period elapses after the fuel supply is performed. The drive of
  A cooling fan control device for a radiator.

Images