Classifications

• • 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
  • F01P7/02—Controlling of coolant flow the coolant being cooling-air
• • 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
  • F01P7/02—Controlling of coolant flow the coolant being cooling-air
  • F01P7/08—Controlling of coolant flow the coolant being cooling-air by cutting in or out of pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/042—Introducing corrections for particular operating conditions for stopping the engine
• • 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
  • F01P2031/00—Fail safe
  • F01P2031/30—Cooling after the engine is stopped
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/06—Fuel or fuel supply system parameters
  • F02D2200/0611—Fuel type, fuel composition or fuel quality

Definitions

• the invention relates to a cooling fan control apparatus and a cooling fan control method for a radiator that are used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline, to control an electric cooling fan provided in the radiator of the internal combustion engine.
• JP 2010-1752 A Japanese Patent Application Publication No. 2010-1752
• a vehicle is provided with a radiator for cooling the engine cooling water.
• the cooling water flowing in the radiator is cooled by the heat exchange performed between the cooling water and the air passing through the radiator when the vehicle runs, that is, running air which is air flow caused by travel of the vehicle.
• the vehicle is also provided with a cooling fan for blowing the air onto the radiator.
• a cooling fan for blowing the air onto the radiator.
• the above-described case is not limited to the internal combustion engines capable of using a fuel in which ethanol is mixed with gasoline having a boiling point higher than that of ethanol, and is generally common to the internal combustion engines capable of using fuels in which other alcohol fuels are mixed with gasoline.
• the invention provides a cooling fan control apparatus and a cooling fan control method for a radiator that can inhibit battery power consumption associated with the drive of the cooling fan, while inhibiting the unstable operation of the engine when the engine is restarted.
• the cooling fan control apparatus for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline, the cooling fan control apparatus that controls drive of an electric cooling fan provided in the radiator of the internal combustion engine, the cooling fan control apparatus comprising: a controller that performs the drive of the cooling fan after the internal combustion engine is stopped, when an alcohol concentration of the fuel is higher than a predetermined concentration, and that restricts the drive of the cooling fan after the internal combustion engine is stopped, when the alcohol concentration of the fuel is equal to or lower than the predetermined concentration.
• the battery power consumption associated with the drive of the cooling fan can be inhibited, while inhibiting the instability of engine operation when the engine is restarted.
• the predetermined concentration may be an alcohol concentration of the fuel when a boiling point of the fuel that changes according to the alcohol concentration of the fuel is at a maximum value attainable by a temperature of the fuel after the internal combustion engine is stopped.
• the controller that prohibits the drive of the cooling fan after the internal combustion engine is stopped, when the alcohol concentration of the fuel is equal to or lower than the predetermined concentration.
• the controller that performs the drive of the cooling fan after the internal combustion engine is stopped, when an evaporation amount of the fuel inside a fuel tank after a supply of the fuel to the fuel tank is performed is less than a predetermined amount, the alcohol concentration of the fuel is taken to be higher than the predetermined concentration, and that restricts the drive of the cooling fan after the internal combustion engine is stopped, when the evaporation amount of the fuel inside the fuel tank after the supply is performed is equal to or greater than the predetermined amount, the alcohol concentration of the fuel is taken to be equal to or lower than the predetermined concentration.
• the alcohol concentration of the fuel stored in the fuel tank can be indirectly determined on the basis of the evaporation amount of the fuel inside the same fuel tank after the fuel is fed into the fuel tank.
• the internal combustion engine is provided with an intake passage for introducing intake air into the internal combustion engine, and an evaporated fuel processing device that introduces an evaporated fuel produced by evaporation of the fuel inside the fuel tank, into the intake passage, the controller that calculates a purge amount integral value which is an integral value of an amount of the evaporated fuel introduced into the intake passage after the supply of the fuel to the fuel tank is performed, that performs the drive of the cooling fan after the internal combustion engine is stopped, when the purge amount integral value is less than a predetermined value, the alcohol concentration of the fuel is taken to be higher than the predetermined concentration, and that restricts the drive of the cooling fan after the internal combustion engine is stopped, when the purge amount integral value is equal to or higher than the predetermined value, the alcohol concentration of the fuel is taken to be equal to or lower than the predetermined concentration.
• the cooling fan control apparatus for a radiator may include an estimation device that estimates an alcohol concentration of the fuel, wherein when the alcohol concentration of the fuel estimated by the estimation device is equal to or lower than the predetermined concentration, the drive of the cooling fan after the internal combustion engine is stopped is restricted.
• the alcohol concentration of the fuel can be determined even if the evaporation amount of the fuel inside the fuel tank after the feed has been performed is not determined. Therefore, the increase in the computation load associated with the calculation of the evaporation amount can be avoided.
• the controller that performs the drive of the cooling fan after the internal combustion engine is stopped, when the alcohol concentration of the fuel is equal to or lower than the predetermined concentration, regardless of the evaporation amount of the fuel inside the fuel tank after the supply of the fuel to the fuel tank.
• the cooling fan control apparatus for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline, the cooling fan control apparatus that controls drive of an electric cooling fan provided in the radiator of the internal combustion engine, the cooling fan control apparatus comprising: a controller that performs the drive of the cooling fan after the internal combustion engine is stopped, when an evaporation amount of the alcohol in the fuel inside a fuel tank after a supply of the fuel into the fuel tank is performed is less than a predetermined amount, and that restricts the drive of the cooling fan after the internal combustion engine is stopped, when the evaporation amount of the alcohol after the supply is performed is equal to or greater than the predetermined amount.
• the cooling fan control apparatus for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline, the cooling fan control apparatus that controls drive of an electric cooling fan provided in the radiator of the internal combustion engine, the cooling fan control apparatus comprising: a controller that performs the drive of the cooling fan after the internal combustion engine is stopped, before a predetermined period elapses from a supply of the fuel to a fuel tank, and that restricts the drive of the cooling fan after the internal combustion engine is stopped, after the predetermined period has elapsed from the supply.
• a cooling fan control method for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline comprising: driving the cooling fan after the internal combustion engine is stopped when an alcohol concentration of the fuel is higher than a predetermined concentration;
• a cooling fan control method for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline the cooling fan control apparatus that controls drive of an electric cooling fan provided in the radiator of the internal combustion engine, comprising: driving the cooling fan after the internal combustion engine is stopped when an evaporation amount of the alcohol in the fuel inside a fuel tank after a supply of the fuel into the fuel tank is performed is less than a predetermined amount; and restricting the drive of the cooling fan after the internal combustion engine is stopped when the evaporation amount of the alcohol after the supply is performed is equal to or greater than the predetermined amount.
• a cooling fan control method for a radiator that is used in an internal combustion engine capable of using a fuel in which gasoline is mixed with an alcohol with a boiling point lower than that of the gasoline comprising: driving the cooling fan after the internal combustion engine is stopped, before a predetermined period elapses from a supply of the fuel to a fuel tank; and restricting the drive of the cooling fan after the internal combustion engine is stopped, after the predetermined period has elapsed from the supply.
• FIG. 1 is a schematic configuration diagram relating to a cooling fan control apparatus for a radiator according to one embodiment of the invention and illustrating the schematic configuration of the internal combustion engine of the vehicle using the apparatus;
• FIG. 2 is a graph illustrating the relationship between the ethanol concentration of a fuel and the boiling point of the fuel
• FIG. 3 is a timing chart illustrating changes in the ethanol concentration of the fuel and also in the boiling point of the fuel;
• FIG. 4 is a flowchart illustrating the processing sequence of the cooling fan drive control performed when the internal combustion engine is stopped in the configuration of the same embodiment
• FIG. 5 is a flowchart illustrating the processing sequence for setting a drive prohibition flag in the same embodiment
• FIG. 6 is a flowchart illustrating the processing sequence for setting a drive prohibition flag in another embodiment.
• FIG. 7 is a flowchart illustrating the processing sequence for setting a drive prohibition flag in another embodiment.
• FIG. 1 illustrates the schematic configuration of an internal combustion engine for a vehicle to which the invention is applied (referred to hereinbelow as internal combustion engine 1 or engine).
• the vehicle is a hybrid car provided with the internal combustion engine 1 and an electric motor as drive sources.
• the internal combustion engine 1 is an engine of a port injection system capable of using a mixed fuel of gasoline and ethanol, which has a boiling point lower than that of the gasoline, as a fuel.
• the internal combustion engine 1 is provided with an intake passage 2 for introducing the intake air into a combustion chamber 11 and an exhaust passage 3 for discharging the exhaust air from the combustion chamber 11.
• An air cleaner 21, a throttle valve 22, and a surge tank 24 are provided in the intake passage 2 in the order of description from the intake upstream side.
• a throttle motor 23 that opening-closing drives the throttle valve 22 is also provided.
• the fuel located in the fuel tank 1 is sucked in by the fuel pump 42, pumped through a fuel supply passage 43, and supplied to an injector 44.
• the fuel is injected from the injector 44 provided in the intake port toward the combustion chamber 11.
• a fuel supply system 4 is constituted by the fuel tank 41, the fuel pump 42, the fuel supply passage 43, and the injector 44.
• the internal combustion engine 1 is also provided with a sparkplug 12 that ignites the gas mixture of the intake air and the fuel injected from the injector 44.
• a cooling apparatus 5 is provided in the vehicle for cooling the internal combustion engine 1.
• the cooling apparatus 5 cools the internal combustion engine 1 by pumping the cooling water discharged from a water pump 52 to a water jacket 53 formed inside a cylinder block and a cylinder head.
• the cooling water discharged from the water jacket 53 is introduced into the radiator 54 via a cooling water passage 51.
• the cooling water circulates inside the radiator 54, the cooling water is cooled by the heat exchange performed between the cooling water and the running air which is air flow caused by travel of the vehicle passing through the radiator 54.
• the vehicle is also provided with an electric cooling fan 55 that blows air onto the radiator 54.
• the internal combustion engine 1 is provided with an evaporated fuel processing device 6 that introduces into the intake passage 2 and processes the evaporated fuel produced by the evaporation of the fuel inside the fuel tank 41.
• the evaporated fuel processing device 6 is provided with a canister 61 having an adsorbing material that adsorbs fuel components.
• the canister 61 is connected via a vapor passage 62 to the fuel tank 41.
• a release passage 64 is connected to the canister 61.
• the canister 61 is also provided with a purge passage 63 communicating with the intake passage 2.
• An electric control valve 65 is provided in the intermediate section of the purge passage 63.
• the control valve 65 when the control valve 65 is open, the air located inside the canister 61 is sucked out into the intake passage 2 through the purge passage 63 by the negative pressure in the intake passage 2.
• the introduction of new air from the release passage 64 results in the desorption of the fuel components adsorbed in the canister 61, the new air is mixed with those fuel components to form a purge gas, and this purge gas is introduced into the intake passage 2.
• the internal combustion engine 1 is provided with various sensors that detect the operating state of the engine, for example, an engine speed sensor 91 that detects an engine speed NE, an intake amount sensor 92 that detects an intake amount GA, a throttle opening degree sensor 93 that detects a throttle opening degree TA, a water temperature sensor 94 that detects a cooling water temperature THW, and an air-fuel ratio sensor 95 that detects an air-fuel ratio AF of the exhaust gas.
• Sensors of other types such as a liquid level sensor 96 that detects a liquid level L of the fuel in the fuel tank 41 and an IG switch 97 are also provided. Those sensors are electrically connected to the electronic control unit 9.
• the electronic control unit 9 is constituted by a central processing unit (CPU) that implements computational processing relating the various types of control, a read only memory (ROM) where programs and data for the aforementioned various types of control are stored, and a random access memory (RAM) where the results of the computational processing are temporarily stored.
• the electronic control unit 9 reads the detection signals for the above-mentioned sensors, executes various types of computational processing, and integrally controls the vehicle (internal combustion engine 1, control valve 65, and cooling fan 55) on the basis for the processing results.
• the electronic control unit 9 drives the start motor, performs cranking, and starts the fuel injection control and ignition control, thereby starting the engine.
• the electronic control unit stops the ignition of fuel from the injector 44 and stops the operation of the engine.
• the electronic control unit 9 performs the air-fuel ratio feedback control by which the fuel injection amount is controlled so as to obtain the stoichiometric air-fuel ratio.
• the electronic control unit 9 also performs the purge control of regulating the amount of the purge gas introduced into the intake passage 2 by adjusting the opening degree of the control vale 65.
• the air-fuel ratio feedback control is performed by feedback controlling the fuel injection amount on the basis of the output of the air-fuel ratio sensor 95, basically so as to maintain the air-fuel ratio close to the stoichiometric air-fuel ratio.
• the purge gas including the fuel components is introduced into the intake passage 2 by means of 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, thereby shifting the air-fuel ratio.
• the reduction correction of the fuel injection amount is performed to reduce the amount of fuel injected from the injector 44 by the amount of fuel contained in the purge gas as long as the purge gas is introduced by the purge control.
• the amount of fuel contained in the purge gas (referred to hereinbelow as purge amount PG) is calculated for each predetermined time interval by the electronic control unit 9 on the basis of the purge gas flow rate and the purge concentration D that is learned by a conventional procedure when the engine operates.
• the above-mentioned reduction correction is performed on the basis of the amount of fuel that has thus been calculated.
• the purge amount PG is calculated by the following Eq. (1).
• the flow rate of the purge gas 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 then the purge amount PG is calculated by multiplying the obtained product by the purge concentration D.
• the electronic control unit 9 also performs the drive control of the cooling fan 55 such that the flow rate of air passing through the radiator 54 is ensured when the sufficient amount of running air which is air flow caused by travel of the vehicle cannot be obtained, for example, when the vehicle is stopped or travels at a low speed.
• the occurrence of the above-described inconveniences is inhibited by performing the below-described drive control of the cooling fan.
• the purge amount PG the amount of evaporated fuel introduced into the intake passage 2, that is, the purge amount PG
• PGS the integral value of the purge amount PG
• FIG. 2 shows the relationship between the ethanol concentration E of the fuel and the boiling point Tbp of the fuel.
• the boiling point (about 78°C) of the ethanol is lower than the boiling point of gasoline (in the present embodiment, 120°C).
• the boiling point Tbp of the fuel is 120°C.
• the boiling point Tbp of the fuel decreases with the increase of the ethanol concentration E of the fuel, and when the ethanol concentration E of the fuel is 20%, the boiling point Tbp of the fuel becomes about 111.5°C.
• the maximum temperature Tmax (in the present embodiment, 112°C) attainable by the temperature of the fuel in the fuel supply system 4 after the engine stop is shown by a dot-dash line.
• the ethanol concentration E of the fuel is equal to or higher than the predetermined concentration Eth within the range of ethanol concentration E of the fuel shown in FIG. 2 (0% ⁇ E ⁇ 20 )
• the boiling point Tbp of the fuel is below the abovementioned maximum attainable temperature Tmax.
• the ethanol contained in the fuel can be evaporated.
• the boiling point Tbp of the fuel and the ethanol concentration E of the fuel change, for example, as shown in FIG. 3.
• the ethanol concentration E of the fuel initially decreases gradually because the ethanol, which has a low boiling point, is the first to start evaporating. Then, following this decrease in ethanol concentration, the boiling point Tbp of the fuel rises gradually from 111.5°C.
• 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 maximum attainable temperature Tmax.
• the ethanol concentration E of the fuel is shown by a dot-dash line and the boiling point Tbp of the fuel is shown by a solid line.
• step S I it is determined whether or not an engine stop command has been outputted. In this case, it is determined whether or not the engine stop command has been outputted when the OFF operation for the IG switch 97 has been detected. When it is not determined that the engine stop command has been outputted (step S I : "NO"), the present timing is assumed not to be the timing for executing the cooling fan drive control and the series of processing steps is ended.
• step S I determines whether or not the engine stop command has been outputted.
• the setting processing procedure for the drive prohibition flag is explained hereinbelow with reference to FIG. 5.
• the series of processing steps shown in FIG. 5 is executed repeatedly with a predetermined period during engine operation.
• the drive prohibition flag F is initially set to "OFF".
• step S 11 it is determined whether or not the fuel has been fed immediately therebefore. In this case, it is determined that the fuel has not been fed immediately therebefore when the level L of the fuel inside the fuel tank 41 that is detected by the liquid level sensor 96 has not risen above a value detected in the preceding control period by an amount equal to or higher than a predetermined value.
• Step S 11 the processing advances to step S12, the increase in the ethanol concentration E of the fuel by the fuel feed is assumed to be possible, "0" is set as the purge amount integral value PGS, and the series of processing steps is ended.
• Step S l l “NO"
• the processing advances to step S13, and the purge amount integral value PGS is updated. More specifically, the purge amount PG introduced into the intake passage 2 within the interval after the preceding control period to the present control period is calculated and the new purge amount integral value PGS is obtained by adding the calculated purge amount PG to the purge amount integral value PGS in the preceding control period.
• the processing then advances to step S 14, and it is determined whether or not the purge amount integral value PGS that has been updated in step S 13 is equal to or higher than a predetermined value PGSth.
• the predetermined value PGSth is set in advance by a test or modulation in the following manner.
• the predetermined value PGSth is set to the purge amount integral value PGS assumed when the ethanol concentration E for the fuel becomes the aforementioned predetermined concentration Eth due to advance in evaporation of ethanol from the state in which the fuel tank 41 is filled with the fuel with an ethanol concentration E of 20%.
• step S 14 When the purge amount integral value PGS is determined in step S 14 to be equal to or higher than the abovementioned predetermined value PGSth (step S 14: "YES"), it is assumed that the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth because a large amount of ethanol has evaporated from the fuel inside the fuel tank 41, the processing then advances to step SI 5, the drive prohibition flag F is set to "ON", and this series of processing steps is ended.
• step S 14 when the purge amount integral value PGS is determined in step S 14 to be less than the predetermined value PGSth (S 14: "NO"), it is assumed that the ethanol has not significantly evaporated from the fuel inside the fuel tank 41 and the ethanol concentration E of the fuel is higher than the predetermined concentration Eth, and this series of processing steps is ended. In this case, it is assumed that the cooling fan 55 should be driven when the engine is stopped and the drive prohibition flag F is left unchanged at "OFF".
• step S5 it is determined whether or not a drive stop condition for stopping the drive of the cooling fan 55 has been established. More specifically, it is determined whether or not the drive stop condition has been established in the case in which the elapsed time since the drive of the cooling fan 55 has been started has become a predetermined time period. In this case, when the drive stop condition has not been established (step S5: “NO"), the drive of the cooling fan 55 is continued and this series of processing steps is ended.
• step S5 the drive stop condition has been determined in step S5 to be established (step S5: "YES")
• step S6 the drive of the cooling fan 55 is stopped, and this series of processing steps is ended.
• step S2 the processing further advances to step S4, the drive of the cooling fan 55 is prohibited, and this series of processing steps is ended.
• the purge amount integral value PGS after the feed of fuel to the fuel tank 41 has been performed is calculated.
• the purge amount integral value PGS is less than the predetermined value PGSth, it is possible that the ethanol concentration E of the fuel exceeds the predetermined concentration Eth and the temperature of the fuel in the fuel supply system 4 after the engine stop can rise above the boiling point Tbp of the fuel, it is assumed that the vapor is generated in the liquid fuel, and the cooling fan 55 is driven after the engine stop.
• the generation of vapor in the liquid fuel can be inhibited, and the occurrence of the vapor lock phenomenon in a subsequent engine restart and the impossibility of fuel injection caused by this phenomenon can be inhibited.
• the electronic control unit 9 corresponds to the cooling fan control apparatus for a radiator in accordance with the invention. The following operation effects can be obtained with the cooling fan control apparatus for a radiator according to the above-described embodiment.
• the internal combustion engine 1 is provided with the evaporated fuel processing device 6 that introduces the evaporated fuel located inside the fuel tank 41 into the intake passage 2 and processes the introduced fuel.
• the electronic control unit 9 is used in the internal combustion engine 1 capable of using a fuel obtained by mixing ethanol and gasoline, which has a boiling point higher than that of ethanol, and controls the drive of the electric cooling fan 55 provided in the radiator 54 of the internal combustion engine 1.
• the electronic control unit 9 calculates the purge amount integral value PGS, which is the integral value of the evaporated fuel amount introduced into the intake passage 2 after the feed of the fuel into the fuel tank 41 has been performed.
• the electronic control unit 9 assumes that the ethanol concentration E of the fuel can be higher than the predetermined concentration Eth and drives the cooling fan 55 after the engine stop. Meanwhile, when the purge amount integral value PGS is equal to or higher than the predetermined value PGSth, the electronic control unit 9 assumes that the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth and prohibits the drive of the cooling fan 55 after the engine stop. With such a configuration the battery power consumption associated with the drive of the cooling fan 55 can be inhibited, while inhibiting the unstable operation of the engine when the engine is restarted.
• the cooling fan control apparatus for a radiator in accordance with the invention is not limited to the configuration presented by way of example in the above-described embodiment, and this apparatus can be also implemented, for example, in the following modes obtained by appropriate modification thereof.
• ethanol is presented as an example of the alcohol contained in the fuel, but the alcohol in accordance with the invention is not limited to ethanol, and the ethanol can be replaced with another alcohol, provided that the boiling temperature of this alcohol is lower than that of gasoline.
• the amount of the evaporated fuel inside the fuel tank 41 after the fuel is fed is determined on the basis of the purge amount integral value PGS, but the invention is not limited to this feature.
• the amount of the evaporated fuel inside the fuel tank 41 after the fuel is fed may be also determined on the basis of changes in the below-described parameters, instead of the purge amount integral value PGS or in addition to the purge amount integral value PGS.
• At least one of the external air temperature, engine operation retention period, and vehicle running distance can be used as the parameter.
• the alcohol with a low boiling point is the first to evaporate. Therefore, with the above-described configuration, when the evaporation amount of the fuel inside the fuel tank after the feed of the fuel to the fuel tank has been performed is less than the predetermined amount, it is assumed that the amount of alcohol evaporated from the fuel stored in the fuel tank is small and a large amount for the alcohol is contained in the fuel, and the alcohol concentration of the fuel can be considered to be higher that the abovementioned predetermined concentration.
• the alcohol concentration of the fuel stored in the fuel tank can be indirectly determined on the basis of the evaporation amount of the fuel inside the fuel tank after the feed of the fuel into fuel tank has been performed.
• the ethanol concentration E of the fuel is determined from the evaporated fuel amount inside the fuel tank 41 after the fuel is supplied therein, but the ethanol concentration E of the fuel may be instead estimated as in the conventional configuration, for example, on the basis of the air-fuel ratio AF of the exhaust gas detected by the air-fuel ratio sensor 95.
• the air-fuel ratio sensor 95 and the electronic control unit 9 correspond to the estimation device in accordance with the invention.
• the drive of the cooling fan after the engine stop may be restricted regardless of the evaporation amount of the fuel inside the fuel tank after the feed of the fuel to into the fuel tank has been performed.
• the decrease mode of the ethanol concentration E of the fuel differs depending on changes in the engine operation state, changes in the external air temperature, or vehicle running distance. Accordingly, it is desirable that the abovementioned predetermined period be variably set on the basis of changes in at least one of those parameters.
• the alcohol with a low boiling point is the first to evaporate.
• the ethanol concentration E of the fuel may be determined from the evaporation amount EVA of ethanol in the fuel inside the fuel tank 41 after the feed of the fuel into the fuel tank 41 has been performed, on the basis of changes in at least one of parameters including changes in the engine operation state, changes in the external air temperature, or vehicle running distance, as shown in the flowchart in FIG. 7.
• the cooling fan 55 may be driven after the engine stop, but after the evaporation amount of ethanol becomes equal to or lower than the predetermined evaporation amount EVAth, the drive of the cooling fan 55 after the engine stop may be prohibited.
• the invention is not limited to such a configuration, and when the ethanol concentration E of the fuel is equal to or lower than the predetermined concentration Eth, the drive of the cooling fan 55 may be restricted, for example, by reducing the amount of electricity supplied to the cooling fan 55 with respect to that in the case where the ethanol concentration of the fuel is higher than the predetermined concentration.
• the ethanol concentration E of the fuel is determined indirectly, but instead a sensor that directly detects the ethanol concentration E of the fuel may be provided and the drive mode of the cooling fan 55 may be set according to the detection results of the sensor.

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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)
• Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

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• 2011
  • 2011-09-12 JP JP2011198565A patent/JP5655748B2/ja not_active Expired - Fee Related
• 2012
  • 2012-09-11 WO PCT/IB2012/001757 patent/WO2013038251A1/en not_active Ceased
  • 2012-09-11 US US14/343,864 patent/US20140224468A1/en not_active Abandoned
  • 2012-09-11 CN CN201280043895.6A patent/CN103782003A/zh active Pending
  • 2012-09-11 EP EP12778388.4A patent/EP2756177A1/en not_active Withdrawn
• 2014
  • 2014-03-11 IN IN429MUN2014 patent/IN2014MN00429A/en unknown

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