JP2009150365A - Property judging method and device of blended fuel and operation control method and device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, if a property of a blended fuel is grasped, it is not possible to conduct proper operation control of an internal combustion engine unless a property of a base fuel contained in the blended fuel. <P>SOLUTION: The property judging device of the fuel of this invention is provided with an in-cylinder pressure sensor 24 for detecting a pressure in a combustion chamber 14 of the engine 10 to which the blended fuel F (mixture of gasoline having unknown low calorific power and alcohol of which property is different from the gasoline and having known low calorific power), a blended fuel low calorific power calculation part 44 for calculating the low calorific power of the blended fuel F supplied to the combustion chamber 14 based on a detection signal from this in-cylinder pressure sensor 24, an alcohol concentration sensor 16 for detecting an alcohol mixing ratio to the gasoline and a base fuel calorific power calculation part 45 for calculating the low calorific power of the gasoline by subtracting the low calorific power of the alcohol corresponding to the blended ratio of the alcohol detected by the alcohol concentration sensor 16 from the low calorific power of the blended fuel F. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mixed fuel property determination method and apparatus and an operation control method and apparatus for an internal combustion engine using such a mixed fuel.

  Most control systems for current internal combustion engines rely on electronic control. In general, correction information is acquired from a correction map prepared in advance according to environmental conditions such as air temperature and cooling water temperature, fuel properties, etc., that is, a lookup table, with respect to preset basic driving conditions of the internal combustion engine. Feedback control and learning control.

Incidentally, for the depletion of fossil fuels, ethanol and biofuels and GTL (G as T o L iquid ) such as methanol are focused fuel from natural gas such as an alcohol a percentage relative to such as gasoline Mixed fuel mixture is used in some countries and regions. In an internal combustion engine using such a mixed fuel, a control system is constructed on the assumption that the properties of the fuel are within a certain range.

  However, depending on the fuel supply situation and social situation in each country, there may be a large variation in the properties of the fossil fuel that is the base, that is, gasoline, depending on the region. In such a case, it may be difficult to control the internal combustion engine smoothly. For this reason, for example, as disclosed in Patent Document 1, it is proposed to use the in-cylinder pressure sensor to obtain the lower heating value of the fuel supplied to the combustion chamber, and to correct the ignition timing and the fuel supply amount based on this. ing.

JP-A-64-88153

  Even in the case of using a mixed fuel to which an alcohol fuel having properties significantly different from those of gasoline is used, it is necessary to set the fuel supply amount and the ignition timing based on the properties of the base gasoline.

  However, in the method disclosed in Patent Document 1, it is possible to calculate the lower heating value of the mixed fuel or to calculate the mixing ratio of alcohol fuel to gasoline, but the base gasoline or alcohol fuel itself It is basically impossible to grasp the properties of For this reason, even if the fuel supply amount and ignition timing are corrected based on the lower heating value of the mixed fuel, it is impossible to perform optimal operation control of the internal combustion engine because at least the properties of the base fuel are unknown. It is.

  A main object of the present invention is to provide a method and an apparatus for accurately determining the properties of a mixed fuel obtained by mixing a first fuel whose properties are unknown and a second fuel whose properties are known. It is also included in the object of the present invention to provide a smooth operation control method and apparatus for an internal combustion engine using such a mixed fuel.

  The first aspect of the present invention is a low calorific value of a mixed fuel obtained by mixing a first fuel having a known low calorific value and a second fuel having a property different from that of the first fuel and having a known low calorific value. Subtracting the lower calorific value of the second fuel at a ratio corresponding to the mixing ratio of the second fuel from the lower calorific value of the mixed fuel. A method for determining the property of a fuel, comprising the step of obtaining a lower heating value of one fuel.

  In the fuel property determination method according to the first aspect of the present invention, the first fuel may be a fossil fuel and the second fuel may be an alcohol fuel.

  In the second aspect of the present invention, a first fuel with an unknown lower heating value and a mixed fuel having a property different from that of the first fuel and a mixture of a second fuel with a known lower heating value are supplied. An in-cylinder pressure sensor for detecting the pressure in the combustion chamber of the internal combustion engine, a mixed fuel heating value calculation unit for calculating a lower heating value of the mixed fuel supplied to the combustion chamber based on a detection signal from the in-cylinder pressure sensor; A fuel concentration sensor for detecting a mixing ratio of the second fuel to one fuel, and a lower heating value of the second fuel in a proportion corresponding to the mixing ratio of the second fuel detected by the fuel concentration sensor is calculated as the mixed fuel heating value. And a first fuel heating value calculation unit that calculates a lower heating value of the first fuel by subtracting from the lower heating value of the mixed fuel calculated by the unit.

  In the present invention, the mixed fuel heating value calculation unit calculates the lower heating value of the mixed fuel supplied to the combustion chamber based on the detection signal from the in-cylinder pressure sensor. The first fuel heating value calculation unit calculates the known lower heating value of the second fuel at a ratio corresponding to the mixing ratio of the second fuel detected by the fuel concentration sensor. By subtracting from the lower heating value, the lower heating value of the first fuel is calculated.

  In the fuel property determination apparatus according to the second aspect of the present invention, the second fuel may be alcohol, and the fuel concentration sensor may be an alcohol concentration sensor.

  According to a third aspect of the present invention, there is provided an internal combustion engine supplied with a base fuel having an unknown low calorific value and a mixed fuel obtained by mixing an additive fuel having a different property from the base fuel and having a known low calorific value. An operation control method comprising: setting a driving condition for an internal combustion engine based on a running state of a vehicle; obtaining a lower heating value of a mixed fuel; obtaining a mixing ratio of an added fuel to a base fuel; Subtracting the lower calorific value of the added fuel in proportion to the fuel mixture ratio from the lower calorific value of the mixed fuel to obtain the lower calorific value of the base fuel, and the vehicle running state based on the lower calorific value of the base fuel And a step of correcting the driving condition for the internal combustion engine set based on the above.

  In the operation control method for an internal combustion engine according to the third aspect of the present invention, the base fuel may be a fossil fuel and the additive fuel may be an alcohol fuel.

  Further, the driving condition for the internal combustion engine set based on the running state of the vehicle may be the fuel supply amount for the internal combustion engine. Alternatively, the internal combustion engine may be a spark ignition type internal combustion engine, and the driving condition for the internal combustion engine set based on the traveling state of the vehicle may be the retard amount of the ignition timing.

  The step of correcting the driving condition for the internal combustion engine set based on the traveling state of the vehicle may further include the step of correcting the driving condition for the internal combustion engine based on the mixture ratio of the added fuel.

  According to a fourth aspect of the present invention, there is provided an internal combustion engine that is supplied with a base fuel having an unknown low calorific value and a mixed fuel obtained by mixing an additive fuel having a different property from the base fuel and having a known low calorific value. A driving control device for setting a driving condition for an internal combustion engine based on a running state of a vehicle, an in-cylinder pressure sensor for detecting a pressure in a combustion chamber of the internal combustion engine, and detection from the in-cylinder pressure sensor Based on the signal, a mixed fuel calorific value calculation unit that calculates a lower calorific value of the mixed fuel supplied to the combustion chamber, a fuel concentration sensor that detects a mixture ratio of the added fuel to the base fuel, and a fuel concentration sensor The lower heating value of the base fuel is subtracted from the lower heating value of the mixed fuel calculated by the mixed fuel heating value calculation unit by subtracting the lower heating value of the added fuel in a proportion corresponding to the mixing ratio of the added fuel. A drive for correcting the driving conditions of the internal combustion engine set by the driving condition setting unit based on the base fuel heating value calculation unit to be output and the lower heating value of the base fuel calculated by the base fuel heating value calculation unit And a condition correction unit.

  In the present invention, the mixed fuel heating value calculation unit calculates the lower heating value of the mixed fuel supplied to the combustion chamber based on the detection signal from the in-cylinder pressure sensor. The base fuel heating value calculation unit calculates the known lower heating value of the added fuel in a proportion corresponding to the mixing ratio of the added fuel detected by the fuel concentration sensor, and the lower heating value of the mixed fuel calculated by the mixed fuel heating value calculation unit. The lower heating value of the base fuel is calculated by subtracting from. The driving condition correction unit corrects the driving condition for the internal combustion engine set by the driving condition setting unit based on the lower heating value of the base fuel calculated by the base fuel heating value calculation unit.

  In the operation control apparatus for an internal combustion engine according to the fourth aspect of the present invention, the added fuel may be alcohol, and the fuel concentration sensor may be an alcohol concentration sensor.

  The driving condition for the internal combustion engine set by the driving condition setting unit may be the fuel supply amount for the internal combustion engine. Alternatively, the internal combustion engine may be a spark ignition type internal combustion engine, and the drive condition for the internal combustion engine set by the drive condition setting unit may be a retard amount of the ignition timing.

  The driving condition correction unit may further correct the driving condition of the internal combustion engine set by the driving condition setting unit based on the mixture ratio of the added fuel detected by the fuel concentration sensor.

  According to the fuel property determination method of the first aspect of the present invention, the lower heating value of the mixed fuel is obtained, the mixing ratio of the second fuel having the lower lower heating value to the first fuel having the unknown lower heating value is obtained, Since the lower calorific value of the second fuel in a proportion corresponding to the mixing ratio of the second fuel is subtracted from the lower calorific value of the mixed fuel, the lower calorific value of the first fuel is obtained, so the first fuel whose properties are unknown When the second fuel whose property is known is contained therein, the lower heating value of the first fuel can be accurately grasped.

  According to the fuel property determination device of the second aspect of the present invention, the mixed fuel heating value calculation unit calculates the lower heating value of the second fuel in a proportion corresponding to the mixing ratio of the second fuel detected by the fuel concentration sensor. Since the first fuel heat generation amount calculation unit for calculating the lower heat generation amount of the first fuel by subtracting from the calculated lower heat generation amount of the mixed fuel is provided, the addition of the known property in the first fuel whose property is unknown When fuel is contained, the lower heating value of the first fuel can be easily and accurately obtained using the in-cylinder pressure sensor and the fuel concentration sensor.

  According to the operation control method for an internal combustion engine of the third aspect of the present invention, after obtaining the lower heating value of the mixed fuel and the mixing ratio of the added fuel with respect to the base fuel, the added fuel in a ratio corresponding to the mixed ratio of the added fuel The lower heating value of the mixed fuel is subtracted from the lower heating value of the mixed fuel to obtain the lower heating value of the base fuel, and based on the lower heating value of the base and the fuel, the drive condition for the internal combustion engine set based on the running state of the vehicle is determined. Since the correction is made, if the base fuel with unknown properties contains the added fuel with known properties, the driving conditions for the internal combustion engine are set optimally by accurately grasping the lower heating value of the base fuel. be able to.

  According to the internal combustion engine operation control apparatus of the fourth aspect of the present invention, the mixed fuel heating value calculation unit calculates the lower heating value of the added fuel corresponding to the mixing ratio of the added fuel detected by the fuel concentration sensor. The base fuel calorific value calculation unit that subtracts the lower calorific value of the mixed fuel calculated to calculate the lower calorific value of the base fuel, and the drive based on the lower calorific value of the base fuel calculated by the base fuel calorific value calculation unit A drive condition correction unit that corrects the drive condition for the internal combustion engine set by the condition setting unit, so that the in-cylinder pressure is included in the case where additive fuel with known properties is included in the base fuel with unknown properties By using the sensor and the added fuel concentration sensor, the lower heating value of the base fuel can be calculated simply and accurately, and thereby the driving conditions for the internal combustion engine can be optimally corrected.

  Embodiments in which the present invention is applied to a vehicle equipped with a spark ignition type internal combustion engine will be described in detail with reference to FIGS. 1 to 5, but the present invention is not limited to such embodiments, and It can be applied to any other technique belonging to the spirit of the invention.

  The concept of the engine system in this embodiment is shown in FIG. 1, and the control block of the main part is shown in FIG. The engine 10 according to this embodiment is configured such that the fuel F stored in the fuel tank 11 passes from the fuel injection valve 12 to the combustion chamber 14 via the fuel supply piping system 13 disposed between the fuel tank 11 and the fuel injection valve 12. This is a spark ignition type in which the fuel is directly injected into the inside and ignited by the spark plug 15. The fuel F used in the present embodiment is a mixture of gasoline as a base fuel and alcohol as an additive fuel, but the properties of gasoline, that is, the lower heating value is unknown, and the properties of alcohol, that is, lower levels. The calorific value is known. As in the present embodiment, the property of gasoline is unknown and the property of alcohol is known, and the reverse relationship may be used. In general, the higher the mixing ratio of alcohol to gasoline is, the more fuel supply amount needs to be increased for the same output, and the ignition timing advance amount needs to be increased.

  The fuel tank 11 incorporates an alcohol concentration sensor 16 that detects a ratio of alcohol in gasoline, that is, a mixing ratio of alcohol (hereinafter simply referred to as alcohol concentration), and a detection signal is output to the ECU 17. It has become so. The alcohol concentration sensor 16 may be incorporated in the fuel supply piping system 13.

  A valve operating mechanism including an intake valve 21 for opening and closing the intake port 18 and an exhaust valve 22 for opening and closing the exhaust port 19 is incorporated in the cylinder head 20 formed with the intake port 18 and the exhaust port 19 respectively facing the combustion chamber 14. ing. In addition to the fuel injection valve 12, the ignition plug 15 that ignites the air-fuel mixture in the combustion chamber 14, and the ignition coil 23 that generates a spark in the ignition plug 15, a cylinder for detecting the pressure in the combustion chamber 14 An internal pressure sensor 24 is also incorporated in the cylinder head 20. A signal detected by the in-cylinder pressure sensor 24 is output to the ECU 17. The fuel injection valve 12 in this embodiment employs a direct injection type that injects the mixed fuel F directly into the combustion chamber 14, but a port injection type that injects into the intake port 18 is adopted. Is also possible.

  At the upstream end side of the intake pipe 26 which is connected to the cylinder head 20 so as to communicate with the intake port 18 and defines the intake passage 25 together with the intake port 18, dust contained in the atmosphere is removed to remove the intake passage 25. An air cleaner 27 is provided for guiding the air. A portion of the intake pipe 26 between the air cleaner 27 and a surge tank 28 formed in the middle of the intake pipe 26 is connected via a throttle actuator 30 based on a depression amount of an accelerator pedal 29 operated by a driver. A throttle valve 31 for adjusting the opening degree of the intake passage 25 is incorporated. For this reason, the accelerator pedal 29 is provided with an accelerator opening sensor 32 for detecting the depression amount, and the detection information is output to the ECU 17. In the present embodiment, the depression operation of the accelerator pedal 29 and the opening / closing operation of the throttle valve 31 are mechanically separated so that the opening / closing operation of the throttle valve 31 can be electrically controlled using the throttle actuator 30. The accelerator pedal 29 and the throttle valve 31 may be mechanically connected. In this case, it is also possible to use a throttle opening sensor that detects the opening of the throttle valve 31 instead of the accelerator opening sensor 32.

  In the middle of the intake pipe 26 between the throttle valve 31 and the air cleaner 27, an air flow meter 33 for detecting the intake flow rate flowing in the intake passage 25 and outputting it to the ECU 17 is attached. The attachment position of the air flow meter 33 in the intake pipe 26 may be upstream from the attachment position of the throttle valve 31, and is not limited to the position shown in FIG.

  A crank angle sensor 38 that detects the rotational phase of the crankshaft 37 to which the piston 34 is connected via the connecting rod 36, that is, the crank angle, and outputs it to the ECU 17 is attached to the cylinder block 35 in which the piston 34 reciprocates. It has been.

  In the middle of the exhaust pipe 40 connected to the cylinder head 20 so as to communicate with the exhaust port 19 and defining the exhaust passage 39 together with the exhaust port 19, harmful substances generated by the combustion of the air-fuel mixture in the combustion chamber 14 are present. A three-way catalyst 41 for detoxification is incorporated. It is also effective to incorporate a plurality of the three-way catalysts 41 in series along the exhaust passage 39 or to incorporate other types of catalysts.

  Accordingly, the intake air supplied from the intake pipe 26 into the combustion chamber 14 through the air cleaner 27 forms an air-fuel mixture with the fuel F injected into the combustion chamber 14 from the fuel injection valve 12, and is caused by the spark of the spark plug 15. The exhaust gas ignited and combusted is exhausted through the three-way catalyst 41 from the exhaust pipe 40 to the atmosphere.

  The ECU 17 controls the fuel injection valve 12 and the ignition coil so that the engine 10 can be smoothly operated according to a preset program based on the detection information from the sensors 16, 24, 32, and 38 and the air flow meter 33 described above. 23 and the like are controlled. The amount of fuel F injected from the fuel injection valve 12 depends on the driving state of the vehicle from the air flow meter 33, the crank angle sensor 38, etc., or the detection signal from the accelerator opening sensor 32, that is, the accelerator pedal 29 operated by the driver. Is set by a fuel injection amount setting unit 42 incorporated in the ECU 17 so as to be a predetermined ratio with respect to the intake amount corresponding to the opening degree of the throttle valve 31 based on information on the depression amount of the throttle valve 31. Further, the energization timing for the ignition coil 23 is set for each cylinder by the ignition timing setting unit 43 of the ECU 17 based on information on the driving state of the vehicle from the accelerator opening sensor 32, the crank angle sensor 38, and the like.

  The ECU 17 in the present embodiment corrects the fuel injection amount set by the fuel injection amount setting unit 42 based on the alcohol concentration in the fuel F and the property of gasoline, that is, the lower heating value of the base fuel, and the ignition timing. A function of correcting the ignition timing set by the setting unit 43 is also provided. Therefore, in addition to the previous fuel injection amount setting unit 42 and ignition timing setting unit 43, the mixed fuel lower heating value calculation unit 44, the base fuel lower heating value calculation unit 45, the injection amount correction unit 46, the ignition timing, and the like. And a correction unit 47.

The mixed fuel lower calorific value calculation unit 44 uses the detection signals from the in-cylinder pressure sensor 24 and the crank angle sensor 38 to calculate the lower calorific value of the base fuel whose properties are unknown, and uses the detection signals from the in-cylinder pressure sensor 24 and the crank angle sensor 38. _M is calculated in advance, and this is output to the base fuel lower heating value calculation unit 45. The specific theory and detailed configuration thereof are described in JP-A-63-268951, JP-A-4-81557, JP-A-4-81534, JP-A-2001-152952, and JP-A-2005-2005. No. 30332 and Japanese Patent Application Laid-Open No. 2007-40208. That is, the mixed fuel lower calorific value calculation unit 44 first sets the pressure in the combustion chamber 14 in the expansion stroke, that is, the in-cylinder pressure P, and the volume V of the combustion chamber 14 at the time of detecting this in-cylinder pressure P by a predetermined index κ. The product PV ^κ with the raised value is calculated as a control parameter related to the instantaneous heat generation amount h when the in-cylinder pressure P is detected, that is, as a heat generation amount index.

The product of the in-cylinder pressure P and the value V ^{κ obtained} by raising the volume V of the combustion chamber 14 to the exponent κ at the time of detection of the in-cylinder pressure P (hereinafter referred to as a heat generation amount parameter) PV ^κ and the instantaneous heat generation amount The fact that h has a correlation, that is, h∽PV ^κ has been described in detail in JP-A-2005-36754 and is well known.

Next, the supply amount of fuel F per cycle to the one cylinder set by the fuel injection amount setting unit 42 using the calculated heat generation amount parameter PV ^κ (hereinafter referred to as a set injection amount). The value divided by τ is calculated as a control parameter relating to the lower heating value Q _M that is the heating value of the true mixed fuel F, that is, the lower heating value index h / τ. The lower heating value Q _M is obtained by dividing the instantaneous heat generation amount h by the set injection amount τ, and can be expressed as Q _M ∽PV ^κ / τ from the relationship of h∽PV ^κ described above.

The lower calorific value Q _M tends to decrease as the alcohol concentration increases. Further, the calculation method is not limited to the above-described embodiment, and other known methods can naturally be adopted.

PV ^κ / τ calculated by the mixed fuel lower heating value calculation unit 44 in this way is output to the base fuel lower heating value calculation unit 45 as the lower heating value Q _M. In this embodiment, the property of the alcohol as the added fuel, that is, the lower heating value is known as described above, and the base fuel lower heating value calculation unit 45 stores the lower heating value Q _A of this added fuel. . Then, based on the lower heating value Q _M of the mixed fuel F calculated by the mixed fuel lower heating value calculation unit 44 and the alcohol concentration C _A (%) in the mixed fuel F detected by the alcohol concentration sensor 16, the base The lower heating value Q _B of the fuel is calculated by the following formula.
Q _B = (100Q _M / C _A ) − {C _A · Q _A / (100−C _A )}

  Data relating to the lower heating value of the base fuel calculated by the lower heating value calculation unit 45 of the base fuel is output to the injection amount correction unit 46 and the ignition timing correction unit 47.

  The injection amount correction unit 46 to which detection information from the alcohol concentration sensor 16 is also transmitted has a map of corrected fuel amounts corresponding to the lower heating value of the base fuel as shown in FIG. There are kinds. Basically, the graph in FIG. 3 tends to translate upward substantially so that the corrected fuel amount increases as the alcohol concentration increases. The fuel injection amount set by the fuel injection amount setting unit 42 is corrected by the corrected fuel amount obtained by the injection amount correcting unit 46 so that the corresponding amount of fuel F is injected from the fuel injection valve 12. The injection valve drive control unit 48 controls the operation of the fuel injection valve 12.

  Similarly to the injection amount correction unit 46, the ignition timing correction unit 47 to which detection information from the alcohol concentration sensor 16 is transmitted also has a map of the ignition timing correction amount corresponding to the lower heating value of the base fuel as shown in FIG. This has multiple types depending on the alcohol concentration. Basically, the graph in FIG. 4 tends to translate downward substantially so that the retard amount decreases, that is, the advance amount increases as the alcohol concentration increases. The ignition coil set by the ignition timing setting unit 43 is corrected by the ignition timing correction amount obtained by the ignition timing correction unit 47, and the ignition coil 15 is ignited at the corrected ignition timing. The drive control unit 49 controls the operation of the ignition coil 23.

  Such a series of control procedures will be described with reference to FIG. 5. First, in step S11, outputs from various sensors such as the accelerator opening sensor 32, the air flow meter 33, and the crank angle sensor 38 are taken in, and S12 is performed. In this step, the fuel injection amount and the ignition timing according to the driving state of the vehicle are set by the fuel injection amount setting unit 42 and the ignition timing setting unit 43.

Next, in step S13, the outputs from the in-cylinder pressure sensor 24 and the crank angle sensor 38 are taken in, the in-cylinder pressure P in the combustion chamber 14 in the expansion stroke, and the volume V of the combustion chamber 14 when the in-cylinder pressure P is detected. The product PV ^κ of the value obtained by multiplying the power by the exponent κ is calculated by the mixed fuel lower heating value calculation unit 44.

The mixed fuel lower calorific value calculation unit 44 reads the fuel injection amount τ set in step S12 in step S15, and uses PV ^κ / τ as the mixed fuel lower calorific value Q _M in step S16. To calculate.

Further, the output of the alcohol concentration sensor 16 is read in step S17, and based on the alcohol concentration and the previous mixed fuel lower heating value Q _M , the lower heating value Q _B of the base fuel is converted into the base fuel in step S18. It is calculated by the lower heating value calculation unit 45.

Based on the lower heating value Q _B of the base fuel calculated by the base fuel lower heating value calculation unit 45, the injection amount correction unit 46 and the ignition timing correction unit 47 perform the fuel injection correction amount and the ignition timing correction in step S19. An amount is set, and based on this, the operation of the fuel injection valve 12 and the operation of the ignition coil 23 are controlled.

  Needless to say, the processing in steps S12 to S19 described above is not performed at the time of cold start where the engine 10 is in an unstable combustion state, but is performed under a stable combustion state.

  Thus, based on the information from the alcohol concentration sensor 16, the in-cylinder pressure sensor 24, and the crank angle sensor 38, the mixed fuel is determined based on the low calorific value of the base fuel (gasoline) whose properties that greatly influence the driving conditions of the engine 10 are unknown. By accurately grasping the base fuel low calorific value calculation unit 45 via the low calorific value calculation unit 44, the driving condition of the engine 10 can be optimally controlled.

  It should be noted that the present invention should be construed only from the matters described in the claims, and in the above-described embodiment, all the changes and modifications included in the concept of the present invention are other than those described. Is possible. That is, all matters in the above-described embodiment are not intended to limit the present invention, and include any configuration not directly related to the present invention. To get.

1 is a conceptual diagram of an embodiment in which the present invention is applied to a vehicle equipped with a spark ignition internal combustion engine. It is a control block diagram of the principal part in embodiment shown in FIG. It is a graph which represents typically the relationship between the low calorific value of a base fuel, and the correction | amendment fuel amount supplied to a combustion chamber. 6 is a graph schematically showing the relationship between the lower heating value of the base fuel and the retard amount of the ignition timing. It is a flowchart showing the control procedure in embodiment shown in FIG.

Explanation of symbols

F mixed fuel 10 engine 11 fuel tank 12 fuel injection valve 13 fuel supply piping system 14 combustion chamber 15 spark plug 16 alcohol concentration sensor 17 ECU
18 Intake Port 19 Exhaust Port 20 Cylinder Head 21 Intake Valve 22 Exhaust Valve 23 Ignition Coil 24 Cylinder Pressure Sensor 25 Intake Passage 26 Intake Pipe 27 Air Cleaner 28 Surge Tank 29 Accelerator Pedal 30 Throttle Actuator 31 Throttle Valve 32 Accelerator Opening Sensor 33 Air Flow Meter 34 Piston 35 Cylinder block 36 Connecting rod 37 Crankshaft 38 Crank angle sensor 39 Exhaust passage 40 Exhaust pipe 41 Three-way catalyst 42 Fuel injection amount setting section 43 Ignition timing setting section 44 Mixed fuel low calorific value calculation section 45 Base fuel low calorific value Calculation unit 46 Injection amount correction unit 47 Ignition timing correction unit 48 Injection valve drive control unit 49 Ignition coil drive control unit

Claims (8)

Obtaining a lower calorific value of a mixed fuel obtained by mixing a first fuel with an unknown lower calorific value and a second fuel having a property different from that of the first fuel and having a known lower calorific value;
Determining a mixing ratio of the second fuel to the first fuel;
Subtracting the lower calorific value of the second fuel in a proportion corresponding to the mixing ratio of the second fuel from the lower calorific value of the mixed fuel to obtain the lower calorific value of the first fuel. Method for determining the properties of The pressure in the combustion chamber of the internal combustion engine to which a mixed fuel obtained by mixing a first fuel with an unknown low calorific value and a second fuel having a property different from that of the first fuel and a known low calorific value is supplied. An in-cylinder pressure sensor for detecting
A mixed fuel heating value calculation unit for calculating a lower heating value of the mixed fuel supplied to the combustion chamber based on a detection signal from the in-cylinder pressure sensor;
A fuel concentration sensor for detecting a mixing ratio of the second fuel to the first fuel;
A lower calorific value of the second fuel at a ratio corresponding to the mixing ratio of the second fuel detected by the fuel concentration sensor is subtracted from the lower calorific value of the mixed fuel calculated by the mixed fuel calorific value calculation unit. And a first fuel heat generation amount calculation unit for calculating a lower heat generation amount of one fuel. An operation control method for an internal combustion engine in which a mixed fuel obtained by mixing a base fuel with an unknown low calorific value and an additive fuel having a different property from the base fuel and a known low calorific value is provided,
Setting driving conditions for the internal combustion engine based on the running state of the vehicle;
Obtaining a lower heating value of the mixed fuel;
Determining a mixing ratio of the added fuel to the base fuel;
Subtracting the lower heating value of the added fuel in a proportion corresponding to the mixing ratio of the added fuel from the lower heating value of the mixed fuel to obtain the lower heating value of the base fuel;
An operation control method for an internal combustion engine, comprising: correcting a drive condition for the internal combustion engine set based on a running state of the vehicle based on a lower heating value of the base fuel.   4. The operation control method for an internal combustion engine according to claim 3, wherein the drive condition for the internal combustion engine set based on the traveling state of the vehicle is a fuel supply amount to the internal combustion engine.   The internal combustion engine is a spark ignition type internal combustion engine, and the driving condition for the internal combustion engine set based on the running state of the vehicle is a retard amount of the ignition timing. Operation control method for internal combustion engine. An operation control device for an internal combustion engine to which a mixed fuel obtained by mixing a base fuel with an unknown low calorific value and an additive fuel having a property different from that of the base fuel and a known low calorific value,
A drive condition setting unit for setting a drive condition for the internal combustion engine based on the running state of the vehicle;
An in-cylinder pressure sensor for detecting the pressure in the combustion chamber of the internal combustion engine;
A mixed fuel heating value calculation unit for calculating a lower heating value of the mixed fuel supplied to the combustion chamber based on a detection signal from the in-cylinder pressure sensor;
An added fuel concentration sensor for detecting a mixture ratio of the added fuel to the base fuel;
The base fuel is obtained by subtracting the lower heating value of the added fuel at a ratio corresponding to the mixing ratio of the added fuel detected by the added fuel concentration sensor from the lower heating value of the mixed fuel calculated by the mixed fuel heating value calculation unit. A base fuel calorific value calculation unit for calculating the lower calorific value of
An internal combustion engine comprising: a driving condition correction unit that corrects the driving condition set by the driving condition setting unit based on the lower heating value of the base fuel calculated by the base fuel heating value calculation unit; Engine operation control device.   7. The operation control apparatus for an internal combustion engine according to claim 6, wherein the drive condition corrected by the drive condition correction unit is a fuel supply amount.   8. The internal combustion engine according to claim 6, wherein the internal combustion engine is a spark ignition internal combustion engine, and the driving condition corrected by the driving condition correction unit is a retard amount of ignition timing. Operation control device.

Images