JP4863119B2 - Internal combustion engine operation control method and apparatus - Google Patents

Description

  The present invention relates to an operation control method and apparatus for a spark ignition type internal combustion engine using two kinds of fuels in an arbitrary mixing ratio.

  In recent years, due to resource depletion and environmental concerns, alcohol fuel has been considered promising as one of the alternative fuels to petroleum fuel, and is partially put into practical use as so-called alcohol mixed fuel in which gasoline and alcohol are mixed. . However, this alcohol-mixed fuel has different calorific value and vaporization characteristics compared to 100% gasoline fuel, and the characteristics also differ depending on the alcohol concentration indicating the mixing ratio to gasoline, so it is assumed that 100% gasoline fuel is used. If the alcohol-mixed fuel is used as it is in the engine, the control air-fuel ratio deviates from the stoichiometric air-fuel ratio, and the exhaust component changes or the drivability deteriorates.

  Therefore, for example, in Patent Document 1, an alcohol concentration detection sensor that detects an alcohol concentration based on a change in the relative permittivity of fuel is disposed in the gasoline tank or upstream or downstream of the gasoline pump, thereby detecting the alcohol concentration. A liquid type identification device is disclosed. Further, for example, Patent Document 2 discloses a technique for detecting the in-cylinder pressure and calculating the alcohol concentration contained in the fuel from the lower heating value based on the heat generation amount obtained from the detected in-cylinder pressure.

JP 2004-125465 A JP-A-64-88153

  As disclosed in Patent Document 1, when the alcohol concentration is detected using an alcohol concentration detection sensor disposed in the gasoline tank or upstream or downstream of the gasoline pump, the fuel property detected by the sensor is The fuel property actually injected and supplied to the engine may differ, and proper control may not be possible. For example, when old fuel remains in the fuel path to the fuel injection valve and fuel with a different alcohol concentration is newly replenished, the alcohol concentration of the fuel immediately before being injected and supplied to the engine is detected. Can not do it. For this reason, especially at the time of cold start where strict ignition conditions are required, the detected value of the alcohol concentration is inappropriate, so that combustion deterioration and misfire are likely to occur, and exhaust emission may be deteriorated.

  Further, since the technique disclosed in Patent Document 2 calculates the alcohol concentration based on the data after combustion, the control depends on the in-cylinder pressure actually generated by combustion, and at the start of combustion at the time of starting. It is essentially impossible to detect fuel properties. For this reason, as in the above-mentioned Patent Document 1, it is difficult to simultaneously correct the ignition timing and the fuel injection amount at the time of cold start where strict ignition conditions are required, and misfire and knocking are likely to occur. There was a risk of worsening emissions.

  An object of the present invention is an operation control method capable of reducing deterioration of combustion and deterioration of exhaust emission due to misfire even in a cold start in a spark ignition internal combustion engine using two kinds of fuels in an arbitrary mixing ratio. And providing an apparatus.

  A first aspect of the present invention is an operation control method for a spark ignition type internal combustion engine using at least one of a first component and a second component different from the first component as fuel, and the fuel is supplied. A step of detecting the pressure in the combustion chamber at a predetermined crank angle phase during the compression stroke, and a ratio of the second component to the first component contained in the fuel supplied to the combustion chamber based on the detected pressure And a step of correcting the amount of fuel supplied to the combustion chamber based on the calculated ratio of the second component.

  In the internal combustion engine operation control method according to the first aspect of the present invention, when the step of correcting the fuel supply amount is a correction that increases the fuel supply amount, this step is performed during the compression process in which the pressure in the combustion chamber is detected. Preferably, it is done.

  The method may further include a step of correcting the ignition timing based on the obtained ratio of the second component. In this case, the step of correcting the ignition timing is preferably performed in the same cycle as the cycle in which the pressure in the combustion chamber is detected.

  The method further includes the step of determining whether or not fuel has been supplied to the fuel tank, and the step of obtaining the ratio of the second component to the first component is performed when it is determined that fuel has been supplied to the fuel tank. Are preferred. In this case, the step of determining whether or not fuel has been supplied to the fuel tank can include the step of determining whether or not the cap of the fuel tank has been opened or closed. Further, the method further includes a step of determining whether or not the integrated value of the amount of fuel supplied to the combustion chamber after the ratio of the second component to the first component has reached a predetermined value or more set in advance. The step of obtaining the ratio of the second component to the first component is preferably performed until it is determined that the integrated value of the fuel has reached a predetermined value.

  According to a second aspect of the present invention, there is provided an operation control device for a spark ignition type internal combustion engine that uses at least one of a first component and a second component different from the first component as fuel. Tank cap opening / closing detection means for detecting the opening / closing operation, an in-cylinder pressure sensor for detecting the pressure in the combustion chamber at a predetermined crank angle phase during the compression stroke, and the tank cap opening / closing detection means Fuel component ratio calculating means for calculating a ratio of the second component to the first component contained in the fuel supplied to the combustion chamber based on the pressure detected by the in-cylinder pressure sensor when the opening / closing operation is detected; The fuel supply amount correcting means for correcting the supply amount of the fuel supplied to the combustion chamber based on the ratio of the second component calculated by the fuel component ratio calculating means; Fee based on a percentage of the second component calculated by the component ratio calculation means, is characterized in that it comprises an ignition timing correction means for correcting the ignition timing.

  In the present invention, when the tank cap opening / closing detection means detects the opening / closing operation of the fuel tank cap, the pressure in the combustion chamber supplied with a predetermined amount of fuel from the fuel injection valve is changed to a predetermined crank angle phase during the compression stroke. This is detected by the cylinder pressure sensor. The fuel component ratio calculation means calculates a ratio of the second component to the first component contained in the fuel supplied to the combustion chamber based on the pressure detected by the in-cylinder pressure sensor. The fuel supply amount correction means corrects the supply amount of the fuel supplied to the combustion chamber based on the ratio of the second component calculated by the fuel component ratio calculation means. Further, the ignition timing correcting means corrects the ignition timing based on the ratio of the second component calculated by the fuel component ratio calculating means.

  In the operation control apparatus for an internal combustion engine according to the second aspect of the present invention, a fuel integrating unit for integrating the amount of fuel supplied to the combustion chamber after obtaining the ratio of the second component to the first component, and the fuel And a comparison determination unit that determines whether or not the value accumulated in the accumulation unit has reached a predetermined value that is set in advance, and the fuel component ratio calculation unit includes the integrated value calculated in the fuel integration unit. The ratio of the second component is preferably calculated until a predetermined value set in advance is reached. In this case, the predetermined value set in advance preferably corresponds to the volume of the fuel supply passage from the fuel tank to the fuel injection valve. Further, when it is determined that the integrated value of the fuel has reached a predetermined value, it is preferable that the ratio of the second component obtained immediately before is maintained until the next fuel supply to the fuel tank.

  The first component may include gasoline and the second component may include alcohol.

  According to the operation control method for an internal combustion engine of the present invention, the pressure in the combustion chamber to which fuel is supplied is detected at a predetermined crank angle phase during the compression stroke, and is included in the fuel supplied to the combustion chamber based on this. The ratio of the second component to the first component is calculated, and the amount of fuel supplied to the combustion chamber is corrected based on the ratio of the second component. It becomes possible to predict the ratio of the second component to the first component contained therein. As a result, it can be reflected in the combustion control in the next cycle at the latest, and in some cases, it can be reflected in the combustion control in the same cycle as the cycle in which the pressure in the combustion chamber is detected. Therefore, it is possible to suppress misfire and knocking that are likely to occur particularly at the time of starting the internal combustion engine, and to prevent deterioration of emissions.

  When correcting the fuel supply amount, if the fuel supply amount is increased during the compression process in which the pressure in the combustion chamber is detected, it should be reflected in the combustion control in the same cycle as the cycle in which the pressure in the combustion chamber is detected. Therefore, misfire and knocking can be surely prevented.

  When correcting the ignition timing based on the obtained ratio of the second component, misfire and knocking can be further suppressed to prevent the emission from deteriorating.

  When the ratio of the second component to the first component is calculated when the fuel is supplied to the fuel tank, the ratio of the second component to the first component is calculated. When the ratio of the second component to the first component is calculated until the integrated value of the fuel supply amount is equal to or greater than a predetermined value, a second value for the first component contained in the fuel is obtained. It is possible to prevent unnecessary control from being performed in a situation where the ratio of components does not change.

  According to the operation control apparatus for an internal combustion engine of the present invention, when the tank cap opening / closing detection means detects the opening / closing operation of the fuel tank cap, the internal combustion engine in the combustion chamber at the predetermined crank angle phase during the compression stroke detected by the in-cylinder pressure sensor. Based on the pressure, the fuel component ratio calculating means for calculating the ratio of the second component to the first component contained in the fuel supplied to the combustion chamber, and the second calculated by the fuel component ratio calculating means. The fuel supply amount correction means for correcting the supply amount of the fuel supplied to the combustion chamber and the ignition timing correction means for correcting the ignition timing are provided based on the ratio of the components of the fuel. The ratio of the second component to the first component contained in can be predicted. Accordingly, it can be reflected in the combustion control in the next cycle at the latest, and in some cases, it can be reflected in the combustion control in the same cycle as the cycle in which the pressure in the combustion chamber is detected. As a result, it is possible to suppress misfire and knocking, which are likely to occur particularly at the start of the internal combustion engine, and to prevent deterioration of emissions.

  A fuel integration unit that integrates the amount of fuel supplied to the combustion chamber after determining the ratio of the second component to the first component, and a value integrated by the fuel integration unit to a predetermined value set in advance. Comparison determination means for determining whether or not the fuel component ratio has been reached, and the fuel component ratio calculation means calculates the ratio of the second component until the integrated value calculated by the fuel integration section reaches a predetermined value set in advance. When the calculation is performed, it is possible to prevent wasteful control in a situation where the ratio of the second component to the first component contained in the fuel does not change.

  One embodiment of the present invention will be described in detail with reference to FIG. 1 to FIG. 8, but the present invention is not limited to such an embodiment and may be applied to any other technique belonging to the spirit of the present invention. Can be applied.

  The concept of the engine system in this embodiment is shown in FIG. The engine 10 according to this embodiment is configured such that the fuel stored in the fuel tank 11 passes from the fuel injection valve 12 into 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 type in which the fuel is directly injected into the gas and ignited by the spark plug 15. The fuel used in this embodiment is a mixture of alcohol and gasoline in an arbitrary ratio. Therefore, the higher the mixing ratio of alcohol to gasoline, the more the fuel supply amount needs to be increased for the same output. In addition, it is necessary to advance the ignition timing.

When fuel is replenished by opening and closing the fuel cap 16 for opening and closing the fuel tank 11, there is a possibility that the replenished fuel may have a different property from the fuel used so far. For this reason, in the present embodiment, a fuel cap sensor 17 for detecting that the fuel cap 16 has been opened and closed is incorporated, and a detection signal thereof is output to the ECU 18. The fuel cap sensor 17 functions as the tank cap opening / closing detection means of the present invention.

  The concept of the fuel cap sensor 17 in this embodiment is shown in FIG. The fuel cap sensor 17 needs to detect the opening / closing operation of the fuel cap 16 and notify the ECU 18 of this regardless of the state of the ignition key switch. Therefore, the fuel cap sensor 17 in the present embodiment includes a proximity switch 20 connected to a battery 19 mounted on the vehicle, and a hold circuit 21 connected to the ECU 18. The proximity switch 20 has such characteristics that it is turned off when the fuel cap 16 is attached to the fuel tank 11 and turned on when the fuel cap 16 is removed from the fuel tank 11. Thereby, useless power consumption of the battery 19 can be avoided. Further, when the proximity switch 20 is switched from the off state to the on state, the hold circuit 21 is switched to an open state corresponding to the on signal of the proximity switch 20, and the proximity switch 20 returns from the on state to the off state. Has such a characteristic that the open state is maintained. When the ECU 18 recognizes the open state of the hold circuit 21, that is, when there is a possibility that fuel has been replenished by opening and closing the fuel cap 16, the hold circuit 21 is closed only when the proximity switch 20 is an off signal. The circuit can be switched to. At this time, a fuel open / close flag described later is set (see FIG. 8).

  A valve operating mechanism including an intake valve 25 for opening and closing the intake port 22 and an exhaust valve 26 for opening and closing the exhaust port 23 is incorporated in the cylinder head 24 in which the intake port 22 and the exhaust port 23 facing the combustion chamber 14 are formed. ing. In addition to the previous fuel injection valve 12, the ignition plug 15 that ignites the air-fuel mixture in the combustion chamber 14, and the ignition coil 27 that generates a spark in the ignition plug 15, a cylinder for detecting the pressure in the combustion chamber 14 An internal pressure sensor 28 is also mounted on the cylinder head 24. A signal detected by the in-cylinder pressure sensor 28 is output to the ECU 18.

  At the upstream end side of the intake pipe 30 that is connected to the cylinder head 24 so as to communicate with the intake port 22 and defines the intake passage 29 together with the intake port 22, dust and the like contained in the atmosphere are removed to remove the intake passage 29. An air cleaner 31 is provided for guiding the air. In the portion of the intake pipe 30 between the air cleaner 31 and the surge tank 32 formed in the middle of the intake pipe 30, the opening degree of the intake passage 29 is based on the depression amount of the accelerator pedal 33 operated by the driver. A throttle valve 34 that adjusts the angle is incorporated. The accelerator pedal 33 is provided with an accelerator opening sensor 35 for detecting the depression amount, and the detection information is output to the ECU 18. In this embodiment, the accelerator pedal 33 and the throttle valve 34 are mechanically connected. However, the depression operation of the accelerator pedal 33 and the opening / closing operation of the throttle valve 34 are separated, and the opening / closing of the throttle valve 34 is performed using an actuator. The operation may be controlled electrically. It is also possible to use a throttle opening sensor that detects the opening of the throttle valve 34 instead of the accelerator opening sensor 35.

  In the middle of the intake pipe 30 between the throttle valve 34 and the air cleaner 31, an air flow meter 36 for detecting the intake air flow flowing in the intake passage 29 and outputting the detected air flow to the ECU 18 is attached. The attachment position of the air flow meter 36 in the intake pipe 30 may be upstream from the attachment position of the throttle valve 34, and is not limited to the position shown in FIG.

  In the middle of the exhaust pipe 38 that is connected to the cylinder head 24 so as to communicate with the exhaust port 23 and defines the exhaust passage 37 together with the exhaust port 23, harmful substances generated by combustion of the air-fuel mixture in the combustion chamber 14 are present. A three-way catalyst 39 for detoxification is incorporated. It is also effective to incorporate a plurality of three-way catalysts 39 in series along the exhaust passage 37.

  Therefore, the intake air supplied from the intake pipe 30 into the combustion chamber 14 through the air cleaner 31 forms an air-fuel mixture with the fuel injected from the fuel injection valve 12 into the combustion chamber 14, and is ignited by the spark of the spark plug 15. The exhaust gas thus generated is exhausted through the three-way catalyst 39 from the exhaust pipe 38 to the atmosphere.

  A crank angle sensor 44 that detects the rotational phase of the crankshaft 43 to which the piston 40 is connected via the connecting rod 42, that is, the crank angle, and outputs it to the ECU 18 is attached to the cylinder block 41 in which the piston 40 reciprocates. It has been.

  The control block of this embodiment is shown in FIG. The ECU 18 described above is configured so that the fuel injection valve 12 and the ignition coil are operated smoothly according to a preset program based on detection information from the sensors 28, 35, 44 and the air flow meter 36 described above. 27 and the like are controlled. In particular, the fuel injection amount from the fuel injection valve 12 is set by a fuel injection amount setting unit 45 incorporated in the ECU 18 based on information from the accelerator opening sensor 35, the air flow meter 36, the crank angle sensor 44, and the like. Is done. Further, the energization timing for the ignition coil 27 is set by the ignition timing setting unit 46 of the ECU 18 based on information from the accelerator opening sensor 35 and the crank angle sensor 44.

The ECU 18 in the present embodiment has a function of estimating the ratio of alcohol to gasoline in the fuel (hereinafter simply referred to as alcohol concentration), correcting the fuel injection amount based on this, and correcting the ignition timing. . Therefore, in addition to the fuel injection amount setting unit 45 and the ignition timing setting unit 46, the alcohol concentration calculation unit 47 as the fuel component ratio calculation means of the present invention and the fuel injection amount integration as the fuel integration unit of the present invention. And a comparison / determination unit 49 as a comparison / determination unit of the present invention .

  The alcohol concentration calculation unit 47 calculates the alcohol concentration in the fuel supplied into the combustion chamber 14 based on the detection information from the in-cylinder pressure sensor 28. In this case, the in-cylinder pressure sensor 28 detects the pressure in the combustion chamber 14 at a predetermined crank angle phase during the compression stroke. The relationship between the in-cylinder pressure at a predetermined crank angle phase during the compression stroke and the alcohol concentration in the fuel injected into the combustion chamber 14 is schematically shown in FIG. As is apparent from this graph, it is understood that the pressure in the combustion chamber 14 in the compression stroke varies depending on the alcohol concentration because the vaporization characteristics are different between gasoline and alcohol. Therefore, the concentration of alcohol contained in gasoline can be uniquely determined by detecting the pressure in the combustion chamber 14 supplied with fuel at a predetermined crank angle phase during the compression stroke. That is, the ratio of the other component to one component can be predicted as long as the fuel is not limited to a mixed fuel of gasoline and alcohol, but is a fuel composed of two types of components having different vaporization characteristics. The alcohol concentration calculation unit 47 in the present embodiment has data that maps the relationship between the pressure in the combustion chamber 14 and the alcohol concentration at a predetermined crank angle phase during the compression stroke as shown in FIG. .

  According to the alcohol concentration calculation unit 47 in this embodiment, since the alcohol concentration in the fuel can be calculated before combustion, the combustion control is performed during the same cycle in which the in-cylinder pressure is detected, except for correction that reduces the fuel. It can be carried out. For this reason, there is an advantage that the occurrence of misfire or knocking at the time of cold start can be surely suppressed.

  The alcohol concentration calculation unit 47 in the present embodiment includes a heat generation amount index calculation unit 50 and a lower heating value index calculation unit 51 in order to calculate a more accurate alcohol concentration.

The heat generation amount index calculation unit 50 calculates the pressure in the combustion chamber 14 in the expansion stroke, that is, the in-cylinder pressure P, and the value obtained by raising the volume V of the combustion chamber 14 at the time of detection of the in-cylinder pressure P by a predetermined index κ. The product PV ^κ 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. The heat generation amount parameter PV ^κ calculated by the heat generation amount index calculation unit 50 is output to the lower heating value index calculation unit 51.

The lower calorific value index calculation unit 51 supplies fuel per cycle to one cylinder in which the heat generation amount parameter PV ^κ is set by the fuel injection amount setting unit 45 (hereinafter referred to as a set injection amount). The value divided by τ is calculated as a control parameter related to the lower heating value Q that is the heating value of the true fuel, that is, the lower heating value index h / τ. The lower heating value Q is obtained by dividing the instantaneous heat generation amount h by the set injection amount τ, and can be expressed as Q∽PV ^κ / τ from the relationship of h∽PV ^κ described above. The lower calorific value Q tends to decrease as the alcohol concentration increases, resulting in a downward-sloping graph as shown in FIG. The lower heating value index calculation unit 51 in the present embodiment has data as a map of the relationship between the lower heating value Q and the alcohol concentration as shown in FIG.

  When the alcohol concentration is detected using the heat generation amount index calculation unit 50 and the lower heating value index calculation unit 51, it is necessary to burn the fuel. Therefore, the combustion control must be reflected in the next and subsequent combustion cycles. It is basically impossible to perform combustion control in a cycle in which the in-cylinder pressure is detected. However, since the alcohol concentration can be calculated with higher accuracy than when the alcohol concentration is calculated before fuel combustion, the alcohol concentration is calculated before fuel combustion for the first cycle after the engine 10 is started. Then, by performing combustion control during the same cycle, the occurrence of misfire and knocking is reliably suppressed, and the heat generation amount index calculation unit 50 and the lower heating value index calculation unit 51 are used in the combustion control after the second cycle. It can be said that detecting the alcohol concentration is a preferable method.

  Based on the injection information from the fuel injection amount setting unit 45, the fuel injection amount integration unit 48 integrates the fuel injection amount into the combustion chamber 14 after starting this combustion control, and outputs this to the comparison determination unit 49. To do.

The comparison determination unit 49 compares the fuel integration information from the fuel injection amount integration unit 48 with the volume of fuel intervening in the fuel supply piping system 13 between the fuel tank 11 and the fuel injection valve 12, and the fuel integration amount Is for stopping the combustion control when the fuel volume exceeds the fuel volume of the fuel supply piping system 13. Therefore, the comparison determination unit 49, the volume of fuel that is interposed in a fuel supply pipe system 13 are stored as a threshold value F _R which is a predetermined value of the present invention. In this way, since new fuel is supplied into the fuel tank and the fuel property is expected to become unstable until it reaches the fuel injection valve 12, the new fuel in the fuel tank 11 is transferred to the fuel injection valve 12. By continuing the combustion control of the present invention until it reaches the value, the occurrence of misfire and knocking can be reliably suppressed.

The fuel injection amount setting unit 45 incorporates a fuel injection amount correction unit 52 that corrects the fuel injection amount based on the alcohol concentration in the fuel calculated by the alcohol concentration calculation unit 47 as the fuel supply amount correction means of the present invention. ing. The fuel injection amount correction unit 52 has data as a map of the relationship between the fuel injection correction amount and the alcohol concentration as shown in FIG.

Further, the ignition timing setting unit 46 incorporates an advance angle correction unit 53 as an ignition timing correction unit of the present invention that corrects the ignition advance amount based on the alcohol concentration in the fuel calculated by the alcohol concentration calculation unit 47. It is. The advance angle correction unit 53 has data as a map of the relationship between the ignition advance correction amount and the alcohol concentration as shown in FIG.

  The procedure of the combustion control according to the present embodiment as described above will be described with reference to FIG. First, in step S11, it is determined whether or not a fuel cap opening / closing flag is set. If fuel supply to the fuel tank 11 is not continuously performed, the fuel cap opening / closing flag is not normally set, and in this case, the process is terminated without doing anything.

If it is determined in step S11 that the fuel cap opening / closing flag is set, that is, the fuel cap 16 has been opened or closed (there is a possibility that fuel has been supplied to the fuel tank 11), the process proceeds to step S12. migration was incremented by one combustion control number C _n, it is determined that combustion control number C _n at S13 in step 1, i.e. whether it is the first time.

When the engine 10 is started, since the combustion control number C _n is first, the process proceeds to step S14, and the alcohol concentration calculation unit 47 calculates the alcohol concentration from the in-cylinder pressure in the compression stroke. Then, from the calculated alcohol concentration, in step S15, the fuel injection correction amount and the ignition advance correction amount are converted into the fuel injection amount correction unit 52 of the fuel injection amount setting unit 45 and the advance amount correction unit of the ignition timing setting unit 46. The fuel is burned by correcting the ignition advance at least during the same cycle. When the fuel injection correction amount requires addition of fuel, that is, when it is determined that the alcohol concentration in the fuel is high, fuel is additionally injected into the combustion chamber 14 during the same cycle before ignition. Conversely, when the fuel injection correction amount requires a reduction in fuel, that is, when it is determined that the alcohol concentration in the fuel is low, the fuel injection amount is corrected in the next combustion cycle.

Further the integration of the fuel injection amount performed by the fuel injection amount integration unit 48 at S16 in step, whether the comparison determination unit is cumulative fuel injection amount F _C is the threshold value F _R over a preset at step S17 Determination is made at 49. Initially, cumulative fuel injection amount F _C is smaller than the threshold value F _R, it returns to step S11 to repeat the foregoing processing. However, in the second and subsequent combustion cycles, the process proceeds from step S13 to step S18 instead of step S14. In step S18, the alcohol concentration is calculated by the heat generation amount index calculation unit 50 and the lower heating value index calculation unit 51 of the alcohol concentration calculation unit 47 from the in-cylinder pressure in the expansion stroke. Then, the process proceeds to step S15 to calculate the fuel injection correction amount and the ignition advance correction amount.

In this way, the combustion control until a new fuel to the fuel supply pipe system 13 filled is repeated, proceeds to step S19, when the cumulative fuel injection amount F _C reaches the threshold value or more F _R at step S17 to reset the fuel cap closing flag, further combustion control number C _n at step S20 resets the integrated value F _C of the fuel injection amount to 0 is reset to 0 and ends this combustion control.

  As described above, the present invention should be construed only from the matters described in the scope of the claims, and in the above-described embodiments, the matters described in all the changes and modifications included in the concept of the present invention are described. Other than 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.

It is a conceptual diagram of the principal part of one Embodiment which applied this invention to the vehicle by which the spark ignition internal combustion engine is mounted. It is a conceptual diagram showing the schematic structure of the fuel cap sensor in embodiment shown in FIG. FIG. 2 is a control block diagram in the embodiment shown in FIG. 1. In the embodiment shown in FIG. 1, it is a graph which represents typically the relationship between the cylinder pressure and alcohol concentration in a predetermined crank angle phase. In the embodiment shown in FIG. 1, it is a graph which represents typically the relationship between the low calorific value and alcohol concentration. 2 is a graph schematically showing a relationship between a fuel injection correction amount and an alcohol concentration in the embodiment shown in FIG. In the embodiment shown in FIG. 1, it is a graph which represents typically the relationship between ignition advance correction amount and alcohol concentration. 2 is a flowchart for controlling fuel injection amount and ignition timing in the embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 11 Fuel tank 12 Fuel injection valve 13 Fuel supply piping system 14 Combustion chamber 15 Spark plug 16 Fuel cap 17 Fuel cap sensor 18 ECU
DESCRIPTION OF SYMBOLS 19 Battery 20 Proximity switch 21 Hold circuit 22 Intake port 23 Exhaust port 24 Cylinder head 25 Intake valve 26 Exhaust valve 27 Ignition coil 28 In-cylinder pressure sensor 29 Intake passage 30 Intake pipe 31 Air cleaner 32 Surge tank 33 Accelerator pedal 34 Throttle valve 35 Accelerator opening Degree sensor 36 Air flow meter 37 Exhaust passage 38 Exhaust pipe 39 Three-way catalyst 40 Piston 41 Cylinder block 42 Connecting rod 43 Crankshaft 44 Crank angle sensor 45 Fuel injection amount setting unit 46 Ignition timing setting unit 47 Alcohol concentration calculation unit 48 Fuel injection amount Integration unit 49 Comparison determination unit 50 Heat generation amount index calculation unit 51 Lower heating value index calculation unit 52 Fuel injection amount correction unit 53 Advance angle correction unit

Claims (7)

An operation control method for a spark ignition internal combustion engine using at least one of a first component and a second component different from the first component as fuel,
Detecting the pressure in the combustion chamber supplied with fuel at a predetermined crank angle phase during the compression stroke;
Determining a ratio of the second component to the first component contained in the fuel supplied to the combustion chamber based on the detected pressure;
An operation control method for an internal combustion engine, comprising: correcting a supply amount of fuel supplied to the combustion chamber based on the obtained ratio of the second component.   2. The internal combustion engine according to claim 1, wherein when the step of correcting the fuel supply amount is a correction that increases the fuel supply amount, this step is performed during a compression process in which the pressure in the combustion chamber is detected. Operation control method.   3. The operation control method for an internal combustion engine according to claim 1, further comprising a step of correcting the ignition timing based on the obtained ratio of the second component. And further comprising determining whether or not the fuel tank has been refilled,
The step of obtaining the ratio of the second component to the first component is performed when it is determined that fuel has been supplied to the fuel tank. An operation control method for an internal combustion engine. Further comprising the step of determining whether or not an integrated value of the amount of fuel supplied to the combustion chamber after the ratio of the second component to the first component has reached a predetermined value or more set in advance.
5. The operation control method for an internal combustion engine according to claim 4, wherein the step of obtaining the ratio of the second component to the first component is performed until it is determined that the integrated value of the fuel has reached a predetermined value. An operation control device for a spark ignition internal combustion engine that uses at least one of a first component and a second component different from the first component as fuel,
Tank cap opening / closing detection means for detecting the opening / closing operation of the fuel tank cap;
An in-cylinder pressure sensor for detecting the pressure in the combustion chamber at a predetermined crank angle phase during the compression stroke;
When the tank cap opening / closing detection means detects the opening / closing operation of the fuel tank cap, the second means for the first component contained in the fuel supplied to the combustion chamber based on the pressure detected by the in-cylinder pressure sensor. Fuel component ratio calculating means for calculating the ratio of components;
Fuel supply amount correction means for correcting the supply amount of fuel supplied to the combustion chamber based on the ratio of the second component calculated by the fuel component ratio calculation means;
An internal combustion engine operation control device comprising: ignition timing correction means for correcting ignition timing based on the ratio of the second component calculated by the fuel component ratio calculation means. A fuel integration unit that integrates the amount of fuel supplied to the combustion chamber after determining the ratio of the second component to the first component, and a value integrated by the fuel integration unit to a predetermined value set in advance. And a comparison determination means for determining whether or not
The internal combustion engine according to claim 6 , wherein the fuel component ratio calculating means calculates the ratio of the second component until the integrated value calculated by the fuel integrating unit reaches a predetermined value set in advance. Operation control device.

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