JP2009036033A - Different fuel mixing determination device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the mixing of different fuel when the unusable different fuel is mixed in fuel supplied to an engine. <P>SOLUTION: When the different fuel (such as light oil, kerosene, and heavy oil) is mixed in the fuel (such as gasoline) supplied to the engine, unburned HC is increased, and an exhaust gas temperature is raised since after-burning in which the unburned HC is burnt at an exhaust port occurs frequently. It is determined whether the exhaust gas temperature detected by an exhaust gas temperature sensor comes out of a normal range or not. When the exhaust gas temperature comes out of the normal range, it is determined that the different fuel (such as light oil, kerosene, and heavy oil) is mixed in the fuel. The mixed ratio of the different fuel is estimated by calculating the mixed ratio of the different fuel according to the exhaust gas temperature by a map or the like. When the different fuel is determined not to be mixed in the fuel, it is determined whether the exhaust gas temperature is higher than a heavy duty determination value, and it is determined that the fuel is heavy duty fuel (such as heavy duty gasoline). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel determination device for an internal combustion engine having a function of determining whether or not a different type of fuel is mixed in the fuel supplied to the internal combustion engine.

Since the nature of the fuel used in the internal combustion engine may vary depending on the region, season, etc., as described in Patent Document 1 (Japanese Utility Model Publication No. 62-597403), An intake air temperature detecting means for detecting the temperature of the intake air and an air-fuel mixture temperature detecting means for detecting the temperature of the air-fuel mixture obtained by mixing the intake air and the fuel are provided, and the difference between the temperature of the intake air and the temperature of the air-fuel mixture is provided. Some fuel properties are determined on the basis of this, and the fuel supply amount is corrected in accordance with the fuel properties.
Japanese Utility Model Publication Sho 62-597403 (first page, etc.)

  By the way, the internal combustion engine includes a gasoline engine using gasoline and a diesel engine using light oil. In recent years, since the number of self-stands where the driver refuels himself / herself is increasing, there is a possibility that the driver will accidentally refuel the gasoline engine vehicle with light oil, which is a different kind of unusable fuel. Moreover, there is a possibility that poor fuel obtained by intentionally mixing different fuels such as light oil and kerosene into gasoline is supplied. Although the fuel properties of gasoline may vary depending on the region and season, etc., the technology disclosed in Patent Document 1 and the like enables normal operation even when gasoline with different fuel properties is supplied to a gasoline engine vehicle. .

  On the other hand, even if different types of fuel such as light oil and kerosene and poor fuel are supplied to the gasoline engine vehicle, the fuel is supplied with some gasoline remaining in the fuel tank. If the mixing ratio of dissimilar fuel to gasoline in the fuel tank is small, the engine can be operated by ignition timing control or the like. However, as the mixing ratio of dissimilar fuel increases, the combustion state of the engine deteriorates. Not only does the engine rotation become unstable and drivability deteriorates, but in the worst case, the engine may stop and become unable to run.

  Even if different types of fuel or poor fuel are supplied with almost no gasoline remaining in the fuel tank, the gasoline remaining in the fuel pipe from the fuel tank to the engine is supplied to the engine at first. When the engine can be operated normally for a while and then there is no gasoline remaining in the fuel pipe and different fuel or poor fuel is injected, the combustion state of the engine deteriorates and the engine rotation starts. The engine may become unstable, and in the worst case, the engine may stop and become unable to run.

  In addition, since the technique disclosed in Patent Document 1 needs to provide two temperature detection means, that is, an intake air temperature detection means and an air-fuel mixture temperature detection means, it cannot satisfy the demand for cost reduction and is provided in the intake passage. In addition, since it is necessary to detect the temperature of the air-fuel mixture with the air-fuel mixture temperature detecting means, it can be applied to an intake port injection type internal combustion engine, but has a drawback that it cannot be applied to a cylinder injection type internal combustion engine.

  The present invention has been made in consideration of these circumstances, and therefore, the object of the present invention is to introduce a mixture of dissimilar fuel when an unusable dissimilar fuel is mixed in the fuel supplied to the internal combustion engine. And a fuel determination device for an internal combustion engine that can be applied to both an intake port injection internal combustion engine and a direct injection internal combustion engine while satisfying the demand for cost reduction It is in.

  In order to achieve the above object, the invention according to claim 1 is provided with an exhaust temperature sensor for detecting the exhaust temperature of the internal combustion engine, and the fuel supplied to the internal combustion engine based on the exhaust temperature detected by the exhaust temperature sensor. Whether different fuel is mixed is determined by the different fuel mixing determination means.

  If unusable dissimilar fuel is mixed into the fuel supplied to the internal combustion engine, unburned HC increases, and after the unburned HC burns at the exhaust port, combustion increases and the exhaust temperature rises. By monitoring, it can be accurately determined whether or not the different fuel is mixed, and when the different fuel is mixed, the mixing of the different fuel can be detected. As a result, when different types of fuel are mixed, it becomes possible to detect the mixing of the different types of fuel and notify the driver with a warning lamp or the like, so that the driver can immediately take measures such as changing the fuel. Can be urged. In addition, when different types of fuel are mixed, the control of the internal combustion engine can be switched to the control for mixing different types of fuel so that the vehicle can travel safely for as long as possible. In addition, the present invention requires only one exhaust temperature sensor, can satisfy the demand for cost reduction, and can determine the presence of different types of fuel based on the exhaust temperature. The present invention can be applied to both an internal combustion engine and a direct injection internal combustion engine.

  In this case, as described in claim 2, when it is determined that the different fuel is mixed, the mixing ratio of the different fuel is estimated by the different fuel mixing ratio estimating means based on the exhaust temperature detected by the exhaust temperature sensor. You may do it. In general, unburned HC increases according to the mixing ratio of different fuels, and afterburning increases accordingly, and the exhaust temperature rises. Therefore, if the exhaust temperature is used, the mixing ratio of different fuels can be estimated. . As a result, when the control of the internal combustion engine is switched to the control for mixing different types of fuel, it is possible to perform appropriate control according to the mixing ratio of different types of fuel.

  The invention according to claim 1 is applied to a gasoline engine that uses gasoline as fuel as in claim 3, and determines whether or not at least one of light oil, kerosene, and heavy oil is mixed as a different fuel. You may make it do. In this way, when light oil, kerosene, or heavy oil is mixed in gasoline supplied to the gasoline engine, it is possible to detect mixing of the light oil, kerosene, or heavy oil.

  Further, as in claim 4, the determination condition for determining whether or not different types of fuel are mixed depends on the temperature of the internal combustion engine or temperature information related thereto (for example, cooling water temperature, oil temperature, etc.). May be changed. In this way, it is possible to appropriately change the determination condition corresponding to the change in the exhaust gas temperature due to the change in the amount of unburned HC (the amount of afterburn) due to the temperature of the internal combustion engine. The determination accuracy of fuel mixing can be improved. Here, as a method of changing the determination condition, the determination value may be corrected, or a determination parameter (for example, exhaust temperature) may be corrected.

  Further, as in claim 5, whether or not the fuel supplied to the internal combustion engine based on the exhaust temperature detected by the exhaust temperature sensor is heavy fuel (fuel having a high boiling point component) is determined by the fuel property determination means. It may be determined. When heavy fuel is supplied to the internal combustion engine, unburned HC increases compared to when light fuel is supplied, and after the unburned HC burns at the exhaust port, afterburning increases and exhaust temperature rises. If the exhaust gas temperature is monitored, it can be accurately determined whether or not the fuel is heavy fuel. In addition, the present invention requires only one exhaust temperature sensor, can satisfy the demand for cost reduction, and can determine heavy fuel based on the exhaust temperature. The present invention can be applied to both an internal combustion engine and a direct injection internal combustion engine.

  The invention according to claim 5 is applied to a gasoline engine that uses gasoline as fuel, as in claim 6, and determines whether or not the fuel supplied to the internal combustion engine is heavy gasoline. good. In this way, the property (heavy or light) of gasoline supplied to the gasoline engine can be determined.

  Further, as in claim 7, the determination condition for determining whether or not the fuel is heavy fuel may be changed according to the temperature of the internal combustion engine or temperature information related thereto. . In this way, the determination condition can be appropriately changed in response to the change in the amount of unburned HC (the amount of afterburn) due to the temperature of the internal combustion engine and the exhaust temperature. The property determination accuracy can be improved. Here, as a method of changing the determination condition, the determination value may be corrected, or a determination parameter (for example, exhaust temperature) may be corrected.

Hereinafter, an embodiment in which the best mode for carrying out the present invention is applied to a gasoline engine (an engine using gasoline as fuel) will be described.
First, a schematic configuration of the entire engine control system will be described with reference to FIG.
An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the engine 11 that is an internal combustion engine, and an air flow meter 14 that detects the intake air amount is provided downstream of the air cleaner 13. A throttle valve 16 whose opening is adjusted by a motor 15 and a throttle opening sensor 17 that detects the opening (throttle opening) of the throttle valve 16 are provided on the downstream side of the air flow meter 14.

  Further, a surge tank 18 is provided on the downstream side of the throttle valve 16, and an intake manifold 20 for introducing air into each cylinder of the engine 11 is provided in the surge tank 18. A fuel injection valve 21 for injecting fuel is attached in the vicinity of the intake port of the intake manifold 20 of each cylinder. An ignition plug 22 is attached to the cylinder head of the engine 11 for each cylinder, and the air-fuel mixture in the cylinder is ignited by spark discharge of each ignition plug 22.

  On the other hand, the exhaust pipe 23 of the engine 11 is provided with an exhaust gas sensor 24 (air-fuel ratio sensor, oxygen sensor, etc.) for detecting the air-fuel ratio or rich / lean of the exhaust gas. A catalyst 25 such as a three-way catalyst for purifying gas is provided. Further, an exhaust gas temperature sensor 39 for detecting an exhaust gas temperature (exhaust gas temperature) is provided on the upstream side of the catalyst 25 in the exhaust pipe 23. The exhaust temperature sensor 39 may be disposed in the vicinity of the exhaust gas sensor 24, or may be disposed upstream or downstream of the exhaust gas sensor 24.

  A cooling water temperature sensor 26 that detects the cooling water temperature and a knock sensor 29 that detects knocking are attached to the cylinder block of the engine 11. A crank angle sensor 28 that outputs a pulse signal every time the crankshaft 27 rotates by a predetermined crank angle is attached to the outer peripheral side of the crankshaft 27. Based on the output signal of the crank angle sensor 28, the crank angle and engine The rotation speed is detected.

  A fuel pump 31 that pumps up fuel is provided in a fuel tank 30 that stores fuel (gasoline). The fuel discharged from the fuel pump 31 is sent to the delivery pipe 33 through the fuel pipe 32 and is distributed from the delivery pipe 33 to the fuel injection valve 21 of each cylinder. A filter 34 and a pressure regulator 35 are connected in the vicinity of the fuel pump 31 in the fuel pipe 32, and the discharge pressure of the fuel pump 31 is adjusted to a predetermined pressure by the pressure regulator 35. Is returned to the fuel tank 30 by the fuel return pipe 36.

  The outputs of the various sensors described above are input to a control circuit (hereinafter referred to as “ECU”) 37. The ECU 37 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium), so that the fuel injection amount of the fuel injection valve 21 can be changed according to the engine operating state. The ignition timing of the spark plug 22 is controlled.

  By the way, even if different types of fuel such as light oil or kerosene or poor fuel mixed with different types of fuel is supplied to the vehicle of the gasoline engine 11, gasoline is supplied in a state where some gasoline remains in the fuel tank 30. In such an electronically controlled engine control system, the engine 11 can be operated by ignition timing control or the like if the mixing ratio of the different fuel to the gasoline in the fuel tank 30 is small. As the ratio increases, not only the combustion state of the engine deteriorates but the engine rotation becomes unstable, the drivability deteriorates, and in the worst case, the engine 11 may stop and become unable to run.

  Therefore, the ECU 37 executes a fuel determination routine shown in FIG. 3 to be described later, thereby dissimilar fuels (light oil, kerosene, heavy oil) that cannot be used as fuel supplied to the engine 11 based on the exhaust temperature detected by the exhaust temperature sensor 39. Or the like) is determined.

  Specifically, when different types of fuel such as light oil, kerosene, and heavy oil are mixed with gasoline supplied to the engine 11, unburned HC increases, and afterburning of the unburned HC at the exhaust port increases. Focusing on the characteristic that the exhaust gas temperature rises, as shown in the time chart of FIG. 2, the exhaust gas temperature detected by the exhaust gas temperature sensor 39 is within a predetermined normal range (for example, the exhaust gas temperature when normal gasoline is supplied). If it is determined that the exhaust gas temperature is out of the normal range, it is determined that a different fuel (light oil, kerosene, heavy oil, etc.) is mixed. Accordingly, it can be accurately determined whether or not the different fuel is mixed, and when the different fuel is mixed, the mixing of the different fuel can be detected promptly.

  Furthermore, when it is determined that different types of fuel are mixed, paying attention to the characteristic that the unburned HC increases according to the mixing ratio of different types of fuel and the afterburning increases accordingly and the exhaust temperature increases. In addition, the mixing ratio of the different fuel is estimated from the exhaust temperature using a map (see FIG. 4) for calculating the mixing ratio of the different fuel according to the exhaust temperature or a mathematical formula.

  On the other hand, when it is determined that the exhaust temperature is within the normal range, it is determined that different fuels (light oil, kerosene, heavy oil, etc.) are not mixed. When heavy gasoline (gasoline with many high-boiling components) is supplied to the exhaust gas, the unburned HC increases and the afterburning increases and the exhaust temperature rises more than when light gasoline is supplied. It is determined whether or not the exhaust temperature detected at 39 is higher than a predetermined heavy determination value (for example, an upper limit value of the exhaust temperature when light gasoline is supplied). As a result, when it is determined that the exhaust temperature is higher than the heavy determination value, it is determined that the gasoline supplied to the engine 11 is heavy gasoline, and it is determined that the exhaust temperature is equal to or lower than the heavy determination value. If it is determined, the gasoline supplied to the engine 11 is determined to be light gasoline.

  The fuel determination of the present embodiment described above is executed by the ECU 37 according to the fuel determination routine of FIG. The processing contents of this routine will be described below.

  The fuel determination routine shown in FIG. 3 is executed at a predetermined cycle while the ECU 37 is powered on, and serves as a different fuel mixing determination means in the claims. When this routine is started, first, at step 101, the exhaust temperature detected by the exhaust temperature sensor 39 is read, and then the routine proceeds to step 102 where it is determined whether the exhaust temperature is out of the normal range (exhaust temperature is on the upper limit side). Whether it is larger than the determination value or smaller than the lower limit side determination value). Here, for example, the upper limit determination value is set to the upper limit value of the exhaust temperature when normal fuel (gasoline) is supplied, and the lower limit determination value is, for example, normal fuel (gasoline) is supplied. The lower limit of the exhaust temperature is set.

  In this case, the determination value (upper limit determination value and lower limit determination value) is changed according to the engine temperature or temperature information (for example, cooling water temperature, oil temperature, etc.) related thereto. As a result, the determination value is appropriately changed in response to the change in the exhaust gas temperature due to the change in the amount of unburned HC (the amount of afterburn) caused by the engine temperature.

  If it is determined in step 102 that the exhaust gas temperature is out of the normal range (the exhaust gas temperature is higher than the upper limit side determination value or lower than the lower limit side determination value), the process proceeds to step 103 and different fuel (light oil) , Kerosene, heavy oil, etc.) is determined to be present, the process proceeds to step 104 where a different fuel mixture warning lamp 38 provided on the instrument panel of the driver's seat is turned on or the instrument panel of the driver's seat is turned on. A warning display unit (not shown) warns the driver of “mixing of different types of fuel”. As a result, the driver is informed early of the mixing of different fuels.

  Thereafter, the process proceeds to step 105, where the mixing ratio of the different fuel is calculated based on the current exhaust temperature with reference to the map of the mixing ratio of the different fuel shown in FIG. Since the unburned HC increases as the mixing ratio of the different fuel increases, the afterburning increases accordingly, and the exhaust temperature tends to rise. Therefore, the map of the mixing ratio of the different fuel shown in FIG. The higher the value is, the higher the mixing ratio of different fuels is. The processing in step 105 serves as a different fuel mixture ratio estimation means in the claims.

  Thereafter, the routine proceeds to step 106 where the operation control of the engine 11 (for example, at least one of fuel injection control, throttle control, torque control, air-fuel ratio control, idle rotation speed control, etc.) is controlled for mixing different types of fuel. To ensure that the vehicle can travel safely for as long as possible. At this time, by performing the control for mixing different fuels according to the mixing ratio of different fuels, appropriate control is performed according to the mixing ratio of different fuels.

  On the other hand, if it is determined in step 102 that the exhaust temperature is within the normal range (the exhaust temperature is within the range from the upper limit side determination value to the lower limit side determination value), the process proceeds to step 107 and light oil, kerosene, heavy oil, etc. It is determined that there is no mixing of different types of fuel.

  After this, the routine proceeds to step 108, where it is determined whether or not the exhaust temperature is higher than a heavy determination value (for example, an upper limit value of the exhaust temperature when light gasoline is supplied). Here, the heavy determination value is a temperature lower than the above-described upper limit side determination value, and is set to, for example, the upper limit value of the exhaust temperature when light gasoline is supplied.

  In this case, the heavy determination value is changed according to the engine temperature or temperature information related to the engine temperature (for example, cooling water temperature or oil temperature). Thus, the heavy determination value is appropriately changed in response to the change in the exhaust gas temperature due to the change in the amount of unburned HC (the amount of afterburn) generated depending on the engine temperature.

  If it is determined in step 108 that the exhaust temperature is higher than the heavy determination value, it is determined that the gasoline supplied to the engine 11 is heavy gasoline. On the other hand, if it is determined in step 108 that the exhaust gas temperature is equal to or lower than the heavy determination value, it is determined that the gasoline supplied to the engine 11 is light gasoline. In addition, you may make it calculate the heavy degree and lightness degree of gasoline with a map or a numerical formula etc. according to exhaust gas temperature. The processing of these steps 108 to 110 plays a role as fuel property determination means in the claims.

  In the present embodiment described above, when light oil, kerosene, heavy oil or the like is mixed in the gasoline supplied to the engine 11, unburned HC increases, and afterburning of the unburned HC at the exhaust port increases. Focusing on the characteristic that the exhaust temperature rises, it is determined whether or not the exhaust temperature is out of the normal range, and when it is determined that the exhaust temperature is out of the normal range, different fuels (light oil, kerosene, heavy oil, etc.) Because it is determined that the fuel is mixed, it is possible to accurately determine whether or not the different fuel is mixed, and when the different fuel is mixed, the mixing of the different fuel can be detected quickly. can do. As a result, when different types of fuel are mixed, it becomes possible to notify the driver of the mixing of the different types of fuel with the different types of fuel mixing warning lamp 38 or the like, so that the driver can be promptly replaced. Can be encouraged. Further, when different types of fuel are mixed, the control of the engine 11 can be switched to the control for mixing different types of fuel so that the vehicle can travel safely as long as possible.

  Moreover, it is sufficient to provide only one exhaust temperature sensor 39, which can satisfy the demand for cost reduction and can determine the presence of different types of fuel on the basis of the exhaust temperature. It is not limited, and even in a cylinder injection engine, it can be determined whether or not different types of fuel (light oil, kerosene, heavy oil, etc.) are mixed in gasoline.

  Furthermore, in the present embodiment, focusing on the characteristic that the unburned HC increases according to the mixing ratio of the different fuel, and the afterburning increases accordingly and the exhaust temperature rises, the different fuel is mixed. When the determination is made, the mixing ratio of the different fuel is estimated based on the exhaust temperature, so that the mixing ratio of the different fuel can be accurately estimated. Thereby, when the control of the engine 11 is switched to the control for mixing different types of fuel, it is possible to perform appropriate control according to the mixing ratio of different types of fuel.

  However, it is needless to say that the present invention may be configured not to estimate the mixing ratio of different fuels when it is determined that different fuels are mixed.

  In this embodiment, the determination values (upper limit determination value and lower limit determination value) for determining whether or not different types of fuel are mixed are used as the engine temperature or temperature information related thereto (for example, the coolant temperature). Therefore, the judgment value is set appropriately in response to the change in the exhaust temperature due to the change in the amount of unburned HC (the amount of afterburn) due to the engine temperature. It can be changed, and the determination accuracy of mixing different types of fuel can be improved.

  In the above embodiment, the determination value for determining whether or not different types of fuel are mixed is changed according to the engine temperature or temperature information related thereto. ) May be corrected according to the engine temperature or temperature information related thereto.

  Further, in this embodiment, when it is determined that the exhaust temperature is within the normal range and no different fuel (light oil, kerosene, heavy oil, etc.) is mixed, whether the exhaust temperature is higher than the heavy determination value or not. If the exhaust temperature is determined to be higher than the heavy determination value, it is determined that the gasoline supplied to the engine 11 is heavy gasoline, and the exhaust temperature is equal to or lower than the heavy determination value. When the determination is made, it is determined that the gasoline supplied to the engine 11 is light gasoline, so that the property (heavy or light) of the gasoline supplied to the engine 11 can be accurately determined. . In addition, since the heavy fuel can be determined based on the exhaust temperature, it is not limited to the intake port injection type engine 11, and whether or not the gasoline supplied to the in-cylinder injection type engine is heavy gasoline. Can also be determined.

  Furthermore, in the present embodiment, the heavy determination value for determining whether or not the gasoline is heavy gasoline is changed according to the engine temperature or temperature information related to the engine temperature (for example, cooling water temperature, oil temperature, etc.). As a result, the heavy judgment value can be appropriately changed in response to the change in the exhaust temperature due to the change in the amount of unburned HC (the amount of afterburn) depending on the engine temperature. The determination accuracy can be improved.

  In the above embodiment, the heavy determination value for determining whether or not the gasoline is heavy gasoline is changed according to the engine temperature or temperature information related thereto. The temperature may be corrected according to the engine temperature or temperature information related thereto.

  Further, in the above embodiment, it is determined whether or not the different fuel is mixed depending on whether or not the exhaust gas temperature is out of the normal range. However, the determination method for mixing the different fuel may be changed as appropriate. For example, the amount of change in the exhaust temperature may be compared with a determination value to determine whether or not different types of fuel are mixed.

  In the above embodiment, it is determined whether or not light oil, kerosene, or heavy oil is mixed in the gasoline supplied to the engine 11 as a different type of fuel. It may be determined whether or not.

  Further, the present invention is not limited to the intake port injection type engine as shown in FIG. 1, and includes an in-cylinder injection type engine, and a fuel injection valve for intake port injection and a fuel injection valve for in-cylinder injection. It can also be applied to dual-injection engines.

  Furthermore, by applying the present invention to a diesel engine that uses light oil as fuel, it is determined whether or not gasoline, which is a different kind of unusable fuel, is mixed in the light oil supplied to the engine based on the exhaust temperature, You may make it determine the property of the light oil supplied to an engine based on exhaust temperature.

  Also, as fuel, the present invention is applied to a bi-fuel engine that can use gasoline, alcohol, and alcohol mixed fuel obtained by mixing alcohol with gasoline, and cannot be used for fuel supplied to the engine based on exhaust temperature. It may be determined whether light oil, kerosene, heavy oil or the like, which is a different type of fuel, is mixed, or the characteristics of the fuel supplied to the engine may be determined based on the exhaust temperature.

It is a schematic block diagram of the whole engine control system in one Example of this invention. It is a time chart explaining the determination method of heterogeneous fuel mixing. It is a flowchart explaining the flow of a process of a fuel determination routine. It is a figure which shows notionally an example of the map of a different fuel mixing ratio.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Intake pipe, 16 ... Throttle valve, 21 ... Fuel injection valve, 22 ... Spark plug, 23 ... Exhaust pipe, 30 ... Fuel tank, 31 ... Fuel pump, 32 ... Fuel piping, 37 ... ECU (different fuel mixture determination means, different fuel mixture ratio estimation means, fuel property determination means), 38 ... different fuel mixture warning lamp, 39 ... exhaust temperature sensor

Claims (7)

An exhaust temperature sensor for detecting the exhaust temperature of the internal combustion engine;
An internal combustion engine comprising: different fuel mixture determination means for determining whether or not a different fuel is mixed in the fuel supplied to the internal combustion engine based on an exhaust temperature detected by the exhaust temperature sensor Fuel judgment device.   A heterogeneous fuel mixture ratio estimation unit configured to estimate a mixture ratio of the heterogeneous fuel based on an exhaust temperature detected by the exhaust temperature sensor when the heterogeneous fuel mixture determination unit determines that the heterogeneous fuel is mixed; The fuel determination device for an internal combustion engine according to claim 1, further comprising: The internal combustion engine is a gasoline engine that uses gasoline as fuel,
3. The fuel for an internal combustion engine according to claim 1, wherein the different fuel mixture determination unit determines whether or not at least one of light oil, kerosene, and heavy oil is mixed as the different fuel. 4. Judgment device.   The heterogeneous fuel mixture determining means changes a determination condition for determining whether or not the heterogeneous fuel is mixed according to the temperature of the internal combustion engine or temperature information related thereto. The fuel determination device for an internal combustion engine according to any one of claims 1 to 3. An exhaust temperature sensor for detecting the exhaust temperature of the internal combustion engine;
And a fuel property determining means for determining whether or not the fuel supplied to the internal combustion engine is heavy fuel based on an exhaust temperature detected by the exhaust temperature sensor. Judgment device. The internal combustion engine is a gasoline engine that uses gasoline as fuel,
6. The fuel determination device for an internal combustion engine according to claim 5, wherein the fuel property determination means determines whether or not the fuel supplied to the internal combustion engine is heavy gasoline.   The fuel property determination means changes a determination condition for determining whether or not the fuel is heavy fuel according to the temperature of the internal combustion engine or temperature information related thereto. The fuel determination device for an internal combustion engine according to claim 5 or 6.

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