JP2010038024A - Fuel temperature control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately control, when heating fuel with a heater, fuel temperature to a lower temperature than the boiling point and surely prevent generation of vapor. <P>SOLUTION: In a fuel heating range (a low-temperature range in which starting is difficult unless the fuel is heated by the heater 19), fuel pressure P is detected by a fuel pressure sensor 20, the fuel temperature T is detected by a fuel temperature sensor 21 and a target fuel temperature Tref (for example a temperature slightly lower than the boiling point of the fuel) is set according to the fuel pressure P and an alcohol concentration of the fuel. When the fuel temperature T is lower than the target fuel temperature Tref, energization to the heater 19 is turned on and the fuel is heated by the heater 19. When the fuel temperature T is equal to or higher than the target fuel temperature Tref, the energization to the heater 19 is turned off and heating of the fuel by the heater 19 is stopped. The energization to the heater 19 is thus controlled so that the fuel temperature T is controlled to be near the target fuel temperature Tref. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel temperature control device for an internal combustion engine that includes fuel heating means for heating fuel supplied to the internal combustion engine.

  In recent years, in response to social demands such as CO2 emission reduction and the use of alternative fuels for oil, internal combustion engines that can use gasoline, alcohol (ethanol, methanol, etc.), and alcohol-mixed fuels that are a mixture of gasoline and alcohol can be used as fuels. The demand for onboard vehicles is increasing. However, alcohol has a larger latent heat of vaporization than gasoline and is difficult to vaporize at low temperatures. Therefore, when alcohol fuel (100% alcohol or mixed fuel containing alcohol) is used, the low-temperature startability of the internal combustion engine deteriorates. There is a problem of doing.

  As a countermeasure against this, as described in Japanese Patent Application Laid-Open No. 5-209579, the fuel supplied to the fuel injection valve is heated by a heater at a low temperature of the internal combustion engine, thereby promoting the vaporization of the injected fuel. There is something like that. In Patent Document 1, the energization amount of the heater is controlled in accordance with the alcohol concentration of the fuel, so that the energization amount of the heater is controlled in response to the change of the startable fuel temperature in accordance with the alcohol concentration of the fuel. Thus, the fuel heating amount (temperature rise amount) is adjusted.

Further, as described in Patent Document 2 (Japanese Patent Application Laid-Open No. 7-77130), the boiling point of the fuel changes in accordance with the fuel pressure by controlling on / off of the heater energization in accordance with the fuel pressure. In some cases, the heating amount of the fuel is adjusted in response to changes in the appropriate fuel temperature.
JP-A-5-209579 (2nd page, etc.) JP-A-7-77130 (page 4, etc.)

  By the way, when the fuel is heated by the heater, the fuel temperature may exceed the boiling point, and vapor (bubbles) may be generated in the fuel. When vapor is generated in the fuel, the fuel injection amount of the fuel injection valve becomes the required injection amount. However, the fuel injection amount fluctuates due to fuel pressure pulsation.

  In general, the boiling point of the fuel (that is, the fuel temperature at which the vapor is generated) changes according to the fuel pressure. Therefore, in order to prevent the vapor from being generated when the fuel is heated, the fuel temperature is changed according to the fuel pressure. It is necessary to control the temperature below the boiling point.

  However, the technique of the above-mentioned Patent Document 1 only controls the energization amount of the heater according to the alcohol concentration of the fuel, and neither the fuel pressure nor the fuel temperature is monitored. Therefore, the fuel temperature is accurately adjusted to a temperature lower than the boiling point. It is not possible to control well, and vapor may be generated when the fuel temperature exceeds the boiling point.

  Moreover, although the technique of the above-mentioned patent document 2 controls on / off of the heater energization according to the fuel pressure, since the fuel temperature is not monitored, the fuel temperature is accurately adjusted to a temperature lower than the boiling point. It is not possible to control well, and vapor may be generated when the fuel temperature exceeds the boiling point.

  The present invention has been made in view of these circumstances. Therefore, the object of the present invention is to accurately control the fuel temperature to a temperature lower than the boiling point when the fuel is heated by the fuel heating means. Another object of the present invention is to provide a fuel temperature control device for an internal combustion engine that can reliably prevent the generation of vapor.

  In order to achieve the above object, an invention according to claim 1 is directed to a fuel temperature control apparatus for an internal combustion engine having a fuel heating means for heating fuel supplied to the internal combustion engine. In addition to detecting or estimating, the fuel pressure is detected or estimated by the fuel pressure determining means, the target fuel temperature is set by the target fuel temperature setting means according to the fuel pressure, and the fuel temperature is set to the target fuel temperature. The heating means is controlled by the fuel temperature control means.

  In this configuration, since the target fuel temperature can be set according to the fuel pressure, the target fuel temperature is set corresponding to the change in the boiling point of the fuel (that is, the fuel temperature at which vapor is generated) according to the fuel pressure. By changing, the target fuel temperature can be set to an appropriate temperature (for example, a temperature slightly lower than the boiling point). Since the heating amount of the fuel heating means can be controlled so that the fuel temperature becomes the target fuel temperature, the fuel temperature can be accurately controlled to a temperature lower than the boiling point, and the generation of vapor can be reliably prevented. it can. As a result, it is possible to prevent shortage of fuel injection amount and fuel pressure pulsation (variation of fuel injection amount) due to vapor generation.

  In this case, a fuel temperature sensor that detects the temperature of the fuel may be used as the fuel temperature determination means. In this way, the actual fuel temperature can be accurately detected by the fuel temperature sensor.

  Alternatively, the temperature of the fuel may be estimated based on the operating state of the fuel heating means and the fuel injection amount of the internal combustion engine. The amount of heat per unit time given from the fuel heating means to the fuel changes according to the operating state of the fuel heating means (for example, supplied power), and per unit time passing through the fuel heating means according to the fuel injection amount of the internal combustion engine Since the fuel amount changes, the fuel temperature can be estimated from the operating state of the fuel heating means and the fuel injection amount of the internal combustion engine. In this case, the fuel temperature sensor can be omitted, and the cost reduction requirement which is an important technical problem in recent years can be satisfied.

  Further, a fuel pressure sensor that detects the fuel pressure may be used as the fuel pressure determination means. In this way, the actual fuel pressure can be accurately detected by the fuel pressure sensor.

  Alternatively, as in claim 5, the present invention is applied to a system including a fuel pump that supplies the fuel in the fuel tank to the internal combustion engine and a pressure regulator that adjusts the discharge pressure of the fuel pump to a predetermined pressure. Alternatively, the fuel pressure may be estimated based on the operating state of the fuel pump. When the fuel pump is on (operating), the pressure regulator regulates the discharge pressure of the fuel pump to maintain the predetermined pressure, and when the fuel pump is off (stopped), the fuel pressure is the predetermined pressure. Therefore, the fuel pressure can be estimated from the operating state (for example, on / off) of the fuel pump. In this case, the fuel pressure sensor can be omitted, and the cost reduction requirement which is an important technical problem in recent years can be satisfied.

  By the way, the boiling point of the fuel (that is, the fuel temperature at which vapor is generated) varies depending on the alcohol concentration of the fuel. Therefore, as in claim 6, the alcohol concentration of the fuel may be detected or estimated by the alcohol concentration determination means, and the target fuel temperature may be set in consideration of the alcohol concentration of the fuel. In this way, the target fuel temperature is changed in response to the change in the boiling point of the fuel according to the alcohol concentration of the fuel, and the target fuel temperature is reliably set to an appropriate temperature (for example, a temperature slightly lower than the boiling point). Can be set to

  Several embodiments embodying the best mode for carrying out the present invention will be described below.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of an entire fuel supply system of an intake port injection engine will be described with reference to FIG.

  The internal combustion engine (not shown) can use gasoline, alcohol (ethanol, methanol, etc.), and alcohol mixed fuel in which gasoline is mixed with alcohol as fuel. Any one of the fuel is supplied to the fuel tank 12 and supplied to the engine. A fuel pump 13 that pumps up the fuel is installed in the fuel tank 12 that stores the fuel. The fuel pump 13 is driven by an electric motor (not shown) that uses a battery (not shown) as a power source. The fuel discharged from the fuel pump 13 is sent to the delivery pipe 15 through the fuel pipe 14, and is distributed from the delivery pipe 15 to the fuel injection valve 16 of each cylinder of the engine.

  A pressure regulator 17 is connected to the fuel pipe 14 in the vicinity of the fuel pump 13. The pressure regulator 17 regulates the discharge pressure of the fuel pump 13 to a predetermined pressure, and the excess fuel exceeding the pressure is returned to the fuel. It is returned to the fuel tank 12 by a pipe 18.

  A heater 19 (fuel heating means) such as a PTC heater (self-temperature adjusting heater) for heating the fuel is provided in the middle of the fuel pipe 14. In the first embodiment, a heater 19 is disposed outside the fuel pipe 14 so that the fuel in the fuel pipe 14 is indirectly heated from the outside of the fuel pipe 14. In addition, a heater may be arrange | positioned inside the fuel piping 14, and the fuel in the fuel piping 14 may be directly heated with a heater etc., and the position of a heater, a kind, etc. may be changed suitably.

  Further, a fuel pressure sensor 20 (fuel pressure determination means) for detecting the fuel pressure in the fuel pipe 14 is disposed on the upstream side of the heater 19 in the fuel pipe 14, and an outlet portion of the heater 19 in the fuel pipe 14. A fuel temperature sensor 21 (fuel temperature determination means) for detecting the fuel temperature in the fuel pipe 14 (that is, the temperature of the fuel heated by the heater 19) is disposed in the vicinity.

  Outputs of these various sensors are input to a control circuit (hereinafter referred to as “ECU”) 22. The ECU 22 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium) to thereby determine the fuel injection amount of the fuel injection valve 16 according to the engine operating state. The ignition timing of a spark plug (not shown) is controlled. The ECU 22 may be composed of a single control circuit that comprehensively controls the engine (fuel injection valve 16, spark plug, etc.), the fuel pump 13, the heater 19 and the like, or an engine control circuit that controls the engine. The pump control circuit for controlling the fuel pump 13 and the heater control circuit for controlling the heater 19 may be provided separately.

  Further, the ECU 22 executes the fuel temperature control routine of FIG. 2 to be described later in order to prevent the vapor from being generated in the fuel when the fuel is heated by the heater 19, thereby performing the fuel temperature control as follows. To do. First, it is determined whether or not the fuel heating region (a low temperature region in which starting is difficult without heating the fuel with the heater 19). If the fuel heating region is determined, the fuel pressure P and the alcohol of the fuel are determined. A target fuel temperature Tref (for example, a temperature slightly lower than the boiling point of the fuel) is set according to the concentration, and it is determined whether or not the fuel temperature T is equal to or higher than the target fuel temperature Tref. As a result, when it is determined that the fuel temperature T is lower than the target fuel temperature Tref, energization of the heater 19 is turned on and the fuel is heated by the heater 19. On the other hand, when it is determined that the fuel temperature T is equal to or higher than the target fuel temperature Tref, the energization of the heater 19 is turned off and the fuel heating by the heater 19 is stopped. As a result, the energization of the heater 19 is controlled so that the fuel temperature T is controlled near the target fuel temperature Tref.

The processing contents of the fuel temperature control routine of FIG. 2 executed by the ECU 22 will be described below.
The fuel temperature control routine shown in FIG. 2 is repeatedly executed at a predetermined cycle while the ECU 22 is powered on. When this routine is started, first, at step 101, it is determined whether or not the fuel heating region (a low temperature region in which starting is difficult without heating the fuel by the heater 19), for example, the cooling water temperature is higher than the startable water temperature. Judgment is made by whether or not it is low. The startable water temperature may be changed according to the alcohol concentration of the fuel. Here, the alcohol concentration of the fuel may be detected by an alcohol concentration sensor. However, in the case of a system that does not include the alcohol concentration sensor, a parameter that varies depending on the alcohol concentration of the fuel, for example, an air-fuel ratio. The alcohol concentration of the fuel may be estimated based on at least one of a feedback correction amount, an air-fuel ratio deviation amount, combustion stability (engine rotation fluctuation), engine torque, fuel pressure increase rate at high temperature start, and the like.

  If it is determined in step 101 that the region is not in the fuel heating region, it is not necessary to heat the fuel. Therefore, the process proceeds to step 107, and this routine is terminated while the heater 19 is turned off.

  On the other hand, if it is determined in step 101 that the fuel heating region is set, the process proceeds to step 102, the fuel pressure P detected by the fuel pressure sensor 20 is read, then the process proceeds to step 103, and the target fuel temperature shown in FIG. The target fuel temperature Tref corresponding to the fuel pressure P and the alcohol concentration of the fuel is calculated with reference to the Tref map.

  Here, in the map of the target fuel temperature Tref, the target fuel temperature Tref corresponding to the fuel pressure P is set for each alcohol concentration of the fuel. FIG. 3 shows an example in which the alcohol concentration of the fuel is a predetermined value. As indicated by the broken line in FIG. 3, the fuel boiling point (ie, the fuel temperature at which vapor is generated) increases as the fuel pressure increases, and the boiling point decreases as the alcohol concentration of the fuel increases. In the map of the target fuel temperature Tref indicated by a solid line, the target fuel temperature Tref increases as the fuel pressure P increases so that the target fuel temperature Tref is slightly lower than the boiling point of the fuel, and the alcohol concentration of the fuel increases. The target fuel temperature Tref is set to be lower as the temperature is higher. The processing in step 103 serves as target fuel temperature setting means in the claims.

  In step 103, the target fuel temperature Tref is calculated according to the fuel pressure P and the alcohol concentration of the fuel. However, the target fuel temperature Tref may be calculated only according to the fuel pressure P. In this case, considering the characteristic that the boiling point becomes lower as the alcohol concentration of the fuel becomes higher, the target fuel temperature Tref is set so that the target fuel temperature Tref becomes lower than the boiling point when the alcohol concentration of the fuel is 100%, for example. Just set a map.

  Thereafter, the process proceeds to step 104, and after reading the fuel temperature T detected by the fuel temperature sensor 21, the process proceeds to step 105, where it is determined whether or not the detected fuel temperature T is equal to or higher than the target fuel temperature Tref. When it is determined that T is lower than the target fuel temperature Tref, the routine proceeds to step 106 where the heater 19 is energized and the heater 19 heats the fuel.

  On the other hand, if it is determined in step 105 that the fuel temperature T is equal to or higher than the target fuel temperature Tref, the process proceeds to step 107, the heater 19 is turned off, and the fuel heating by the heater 19 is stopped. Through these steps 105 to 107, the process of controlling the energization of the heater 19 is performed so as to control the fuel temperature T in the vicinity of the target fuel temperature Tref, and the role as the fuel temperature control means in the claims is performed. Fulfilled.

  In the first embodiment described above, since the target fuel temperature Tref is set according to the fuel pressure P and the alcohol concentration of the fuel, the boiling point (that is, the vapor of the fuel) depends on the fuel pressure P and the alcohol concentration of the fuel. The target fuel temperature Tref can be changed to set the target fuel temperature Tref to an appropriate temperature (for example, a temperature slightly lower than the boiling point) in response to the change in the generated fuel temperature). Since the energization of the heater 19 is controlled so that the fuel temperature T is controlled near the target fuel temperature Tref, the fuel temperature T can be accurately controlled to a temperature lower than the boiling point, and the generation of vapor is prevented. It can be surely prevented. As a result, it is possible to prevent shortage of fuel injection amount and fuel pressure pulsation (variation of fuel injection amount) due to vapor generation.

  Next, Embodiment 2 of the present invention will be described with reference to FIGS. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In the second embodiment, as shown in FIG. 4, the fuel temperature sensor is omitted, and the other system configuration is the same as the configuration of FIG. 1 described in the first embodiment.
Then, the ECU 22 executes a fuel temperature control routine of FIG. 5 to be described later, thereby performing the fuel temperature control based on the operating state of the heater 19 and the fuel injection amount Q of the fuel injection valve 16 and the like. I try to estimate.

  The amount of heat per unit time given from the heater 19 to the fuel changes according to the operating state of the heater 19 (for example, the supplied power W), and per unit time passing through the heater 19 according to the fuel injection amount Q of the fuel injection valve 16. Therefore, the fuel temperature T can be estimated from the operating state of the heater 19, the fuel injection amount Q of the fuel injection valve 16, and the like.

  Hereinafter, the processing content of the fuel temperature control routine of FIG. 5 will be described. In this routine, when it is determined in step 201 that the fuel heating region is set, the process proceeds to step 202, the fuel pressure P detected by the fuel pressure sensor 20 is read, and then the process proceeds to step 203 where the target fuel temperature shown in FIG. The target fuel temperature Tref corresponding to the fuel pressure P and the alcohol concentration of the fuel is calculated with reference to the Tref map. As described above, the target fuel temperature Tref may be calculated according to only the fuel pressure P.

  Thereafter, the process proceeds to step 204, and after calculating the fuel injection amount Q of the fuel injection valve 16 per unit time (time Δt corresponding to the calculation period of the fuel temperature), the process proceeds to step 205, where the vicinity of the outlet of the heater 19 is calculated. The fuel temperature T is estimated by calculating the fuel temperature T in the fuel pipe 14 by the following equation.

  Here, T (i) is the calculated value of the current fuel temperature, and T (i-1) is the calculated value of the previous fuel temperature. Ρ is the density of the fuel, and c is the specific heat of the fuel. Further, Tcool is the fuel temperature before heating (the cooling water temperature may be substituted), and W is the power supplied to the heater 19 (0 when energized is off). Further, Δt is a time corresponding to the calculation cycle of the fuel temperature, and Qtotal is the amount of fuel in the fuel pipe 14 from the inlet portion to the outlet portion of the heater 19. The processing in step 205 serves as fuel temperature determination means in the claims.

  Thereafter, the process proceeds to step 206, where it is determined whether or not the estimated fuel temperature T is equal to or higher than the target fuel temperature Tref. If it is determined that the fuel temperature T is lower than the target fuel temperature Tref, the process proceeds to step 207. The heater 19 is turned on and the heater 19 heats the fuel. On the other hand, if it is determined in step 206 that the fuel temperature T is equal to or higher than the target fuel temperature Tref, the process proceeds to step 208 where the heater 19 is turned off and the fuel heating by the heater 19 is stopped.

  In the second embodiment described above, when the fuel temperature control is performed, the fuel temperature T is estimated based on the output power W of the heater 19, the fuel injection amount Q of the fuel injection valve 16, and the like. The sensor can be omitted, and the demand for cost reduction which is an important technical problem in recent years can be satisfied. Note that the method for estimating the fuel temperature T may be changed as appropriate.

  Next, Embodiment 3 of the present invention will be described with reference to FIGS. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

In the third embodiment, as shown in FIG. 6, the fuel pressure sensor is omitted, and the other system configuration is the same as the configuration of FIG. 1 described in the first embodiment.
The ECU 22 estimates the fuel pressure P based on the operating state of the fuel pump 13 when performing fuel temperature control by executing a fuel temperature control routine of FIG.

  When the fuel pump 13 is on (operating), the pressure regulator 17 regulates the discharge pressure of the fuel pump 13 to a predetermined pressure Pmax, the fuel pressure P is maintained at the predetermined pressure Pmax, and the fuel pump 13 is off (stopped). In this case, since the fuel pressure P is lowered to a pressure lower than the predetermined pressure Pmax, the fuel pressure P can be estimated from the operating state (for example, on / off) of the fuel pump 13.

  Hereinafter, the processing content of the fuel temperature control routine of FIG. 7 will be described. In this routine, when it is determined in step 301 that the fuel heating region is set, the routine proceeds to step 302, where it is determined whether the fuel pump 13 is on or off.

  Thereafter, the process proceeds to step 303, and when the fuel pump 13 is on, it is estimated that the fuel pressure P is a predetermined pressure Pmax, and a temperature Ton slightly lower than the boiling point when the fuel pressure P is the predetermined pressure Pmax is set. Set as target fuel temperature Tref. On the other hand, when the fuel pump 13 is off, it is estimated that the fuel pressure P has decreased to a pressure lower than the predetermined pressure Pmax, and the fuel pressure P is lower than the predetermined pressure Pmax (for example, atmospheric pressure). A temperature Toff slightly lower than the boiling point is set as the target fuel temperature Tref. In this case, the function of estimating the fuel pressure P based on the on / off state of the fuel pump 13 serves as fuel pressure determination means in the claims.

  Thereafter, the process proceeds to step 304, and after reading the fuel temperature T detected by the fuel temperature sensor 21, the process proceeds to step 305, where it is determined whether or not the detected fuel temperature T is equal to or higher than the target fuel temperature Tref. If it is determined that T is lower than the target fuel temperature Tref, the routine proceeds to step 306 where energization of the heater 19 is turned on and the fuel is heated by the heater 19.

  On the other hand, if it is determined in step 305 that the fuel temperature T is equal to or higher than the target fuel temperature Tref, the process proceeds to step 307, the energization of the heater 19 is turned off, and the fuel heating by the heater 19 is stopped.

  By setting the target fuel temperature Tref when the fuel pump 13 is off to a sufficiently low temperature, the energization of the heater 19 is always turned off when the fuel pump 13 is off, Heating may be stopped.

  In the third embodiment described above, the fuel pressure P is estimated on the basis of the on / off state of the fuel pump 13 when performing the fuel temperature control. Therefore, the fuel pressure sensor can be omitted. Therefore, it is possible to satisfy the demand for cost reduction, which is an important technical problem in recent years.

The method for estimating the fuel pressure P may be changed as appropriate. For example, the fuel pressure P is estimated based on the load of the fuel pump 13 (for example, the drive current or drive voltage of the fuel pump 13). Also good.
In the third embodiment, the fuel temperature T is detected by the fuel temperature sensor 21, but the fuel temperature T may be estimated.

  In addition, the present invention is not limited to the intake port injection type engine, but is an in-cylinder injection type engine or a dual injection type engine having both a fuel injection valve for intake port injection and a fuel injection valve for in-cylinder injection It can also be applied to.

It is a schematic block diagram of the whole fuel supply system in Example 1 of this invention. 4 is a flowchart for explaining a flow of processing of a fuel temperature control routine according to the first embodiment. It is a figure which shows notionally an example of the map of target fuel temperature Tref. It is a schematic block diagram of the whole fuel supply system of Example 2. FIG. 6 is a flowchart for explaining a flow of processing of a fuel temperature control routine according to a second embodiment. It is a schematic block diagram of the whole fuel supply system of Example 3. 12 is a flowchart for explaining a flow of processing of a fuel temperature control routine of a third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Fuel tank, 13 ... Fuel pump, 14 ... Fuel piping, 16 ... Fuel injection valve, 17 ... Pressure regulator, 19 ... Heater (fuel heating means), 20 ... Fuel pressure sensor (fuel pressure determination means), 21 ... Fuel temperature Sensor (fuel temperature determination means), 22... ECU (target fuel temperature setting means, fuel temperature control means, fuel pressure determination means, fuel temperature determination means)

Claims (6)

In a fuel temperature control device for an internal combustion engine comprising a fuel heating means for heating fuel supplied to the internal combustion engine,
Fuel temperature determination means for detecting or estimating the temperature of the fuel;
Fuel pressure determination means for detecting or estimating the pressure of the fuel;
Target fuel temperature setting means for setting a target fuel temperature according to the fuel pressure detected or estimated by the fuel pressure determination means;
A fuel temperature control device for an internal combustion engine, comprising: fuel temperature control means for controlling the fuel heating means so that the fuel temperature detected or estimated by the fuel temperature determination means becomes the target fuel temperature.   2. The fuel temperature control device for an internal combustion engine according to claim 1, wherein the fuel temperature determination means is a fuel temperature sensor that detects the temperature of the fuel.   2. The fuel temperature control device for an internal combustion engine according to claim 1, wherein the fuel temperature determination means estimates the temperature of the fuel based on an operating state of the fuel heating means and a fuel injection amount of the internal combustion engine.   4. The fuel temperature control device for an internal combustion engine according to claim 1, wherein the fuel pressure determination means is a fuel pressure sensor that detects the pressure of the fuel. A fuel pump for supplying the fuel in the fuel tank to the internal combustion engine;
A pressure regulator that regulates the discharge pressure of the fuel pump to a predetermined pressure;
4. The fuel temperature control apparatus for an internal combustion engine according to claim 1, wherein the fuel pressure determination means estimates the pressure of the fuel based on an operating state of the fuel pump. Comprising alcohol concentration determination means for detecting or estimating the alcohol concentration of the fuel;
6. The internal combustion engine according to claim 1, wherein the target fuel temperature setting means sets the target fuel temperature in consideration of the alcohol concentration of the fuel detected or estimated by the alcohol concentration determination means. Engine fuel temperature control device.

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