JP4376913B2 - Internal combustion engine fuel property determination device and internal combustion engine control device - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a fuel property determination device for an internal combustion engine and a control device for the internal combustion engine, and more particularly to a fuel property determination device for an internal combustion engine that detects the use of heavy fuel for preventing misdiagnosis and preventing deterioration of drivability and the internal combustion engine. The present invention relates to a control device.

  In order to prevent deterioration in drivability due to the use of heavy fuel, a fuel property determination device for an internal combustion engine that detects the use of heavy fuel has been proposed.

  As this fuel property determination device, a primary determination process for calculating the degree of decrease in the engine speed immediately after the engine is started and determining whether or not the fuel property is likely to be heavy depending on whether or not this is greater than or equal to a determination value. If it is determined in the primary determination process that there is a possibility of heavy fuel, the intake air amount is temporarily increased, and the fuel property is heavy based on the amount of fluctuation in the engine speed thereafter. There is one that executes a secondary determination process that finally determines whether or not (for example, Patent Document 1).

  In this fuel property determination device, by performing the secondary determination process, it becomes possible to distinguish between rotation depression due to lean (heavy fuel) and rotation depression due to rich, and that rotation depression due to rich is due to heavy fuel. It is possible to prevent erroneous determination.

JP 2006-194086 A

  However, in the fuel property determination device, the primary determination process merely calculates the degree of decrease in the engine speed immediately after engine startup and determines whether or not this is greater than or equal to the determination value, which is caused by heavy fuel. Since the decrease in engine speed may not be significant, the accuracy of accurately determining that the internal combustion engine is being operated by heavy fuel is lacking. In addition, it is difficult to perform quick fuel property determination because of the secondary determination processing.

  By the way, in recent years, for the purpose of early activation of the catalyst, the exhaust reduction control in which the ignition timing is retarded immediately after the start is often executed by using the engine speed increase as a trigger at the time of cold start. In this case, the exhaust gas reduction control diagnosis at the time of starting (hereinafter referred to as cold engine strategy diagnosis) diagnoses a state in which the engine speed does not increase at the time of cold engine start. However, when the fuel is a heavy fuel or the like, the engine speed does not increase at the start of the cold engine. Therefore, if the cold engine strategy diagnosis is executed, an erroneous diagnosis is made. For this reason, it is possible to quickly and accurately determine that the internal combustion engine is being operated by the heavy fuel in order to prevent the wrong diagnosis by prohibiting the execution of the cold machine strategy diagnosis at the time of heavy fuel. There is a strong demand for the development of a fuel property determination device.

  The present invention has been made in view of the problems to be solved, and an object of the present invention is to quickly and accurately determine that an internal combustion engine is being operated by heavy fuel. An object of the present invention is to provide a fuel property determination device for an internal combustion engine.

In order to achieve the above object, a fuel property determination device for an internal combustion engine according to the present invention measures a time required for the crankshaft of the internal combustion engine to rotate a predetermined angle and outputs a time signal indicating the measurement time. And a two-rotation component signal generated each time the crankshaft makes two revolutions or a one-rotation component signal generated every time the crankshaft makes one rotation from the time signal output by the means and the time signal measuring means , and fuel property determination parameter calculating means for calculating a fuel property determination Paremeta which is the difference between the time signal and the time signal of the previous ignition current ignition time of the second rotation component signal or said first rotation component signal, the fuel property judgment parameter fuel property judgment parameter for detecting a parameter correlating to the kurtosis of the distribution of the statistical nature of the fuel property judgment parameter calculated by the calculation means A total processing means is characterized by having a determining fuel nature determining means for fuel nature used in the internal combustion engine based on a parameter correlating to the kurtosis of the distribution.

  In addition, a specific aspect of the fuel property determination device for an internal combustion engine of the present invention includes fuel property determination execution permission means for selectively setting execution permission of fuel property determination, and fuel is determined by the fuel property determination execution permission means. The fuel property determining means determines the fuel property only when execution of property determination is permitted.

The fuel property determination execution permission means executes fuel property determination in which the internal combustion engine is idling, the engine water temperature is within a predetermined range, the environmental temperature is within a predetermined range, the battery voltage is within a predetermined range, and misfire determination is not performed. when satisfied all the conditions of no, it is characterized in allowing execution of the decision.

Furthermore, other specific aspects of the fuel property determination device for an internal combustion engine of the present invention, the slice level for determining the predetermined range to detect a parameter correlated to the kurtosis of the distribution of the fuel property determination parameter, the internal combustion engine The fuel property determining means calculates the number of times of calculating the fuel property determination parameter within the predetermined range and the fuel property determination parameter outside the predetermined range. When the ratio or the difference in the number of operations is greater than or equal to a predetermined value, it is determined that the fuel is heavy fuel, and the predetermined value for the heavy fuel determination of the fuel property determining means is determined by the water temperature of the internal combustion engine. And having a diagnosis prohibition judging means for prohibiting judgment diagnosis based on a judgment result of the fuel property judging means .

  Furthermore, the control device for an internal combustion engine of the present invention prohibits a diagnosis that may be erroneously determined when the fuel is heavy when the fuel property determination means of the fuel property determination device determines that the fuel is heavy. When the fuel property determining means of the fuel property determining device determines that the fuel is heavy fuel, the fuel control is corrected to be suitable for heavy fuel, and the fuel property determining device of the property determining device is When it is determined that the fuel is a quality fuel, the ignition control is corrected to be suitable for the heavy fuel.

  According to the fuel property determination device for an internal combustion engine according to the present invention, the fuel property is determined from the statistical property of the fuel property determination parameter calculated from the time signal without directly using the time signal for the fuel property determination. It becomes possible to accurately determine that the internal combustion engine is being operated by the fuel.

  An embodiment of a fuel property determination device for an internal combustion engine and a control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 shows one embodiment of an internal combustion engine system to which a fuel property determination device for an internal combustion engine and a control device for the internal combustion engine according to the present invention are applied.

  The internal combustion engine 100 is a multi-cylinder engine having a plurality of combustion chambers 101. An air cleaner 102, a throttle valve 103, and an intake manifold 104 are connected to the internal combustion engine 100 as an intake system. The air flowing from the air cleaner 102 is adjusted (measured) by the throttle valve 103 and is sucked into the combustion chamber 101 through the intake manifold 104. The amount of air sucked into the combustion chamber 101 is measured by the flow rate detection means 105.

  A fuel injection valve 106 that injects fuel toward each combustion chamber 101 is attached to the intake manifold 104. The fuel tank 107 stores fuel such as gasoline. The fuel in the fuel tank 107 is sucked and pressurized by the fuel pump 108 and then supplied to the fuel injection valve 106 through the fuel pipe 110 having the pressure regulator 109. Of the fuel supplied to the fuel injection valve 106, excess fuel is returned to the fuel tank 107.

  The fuel injected from the fuel injection valve 106 is mixed with air and supplied to each combustion chamber (cylinder) 101.

  An ignition plug 111 is attached to the internal combustion engine 100 for each combustion chamber 101. The spark plug 111 is subjected to a spark discharge when a high voltage is applied by the ignition coil device 112, and ignites a mixture of fuel and air in the combustion chamber 101.

  An exhaust pipe 113, a three-way catalyst 114, and a muffler 115 are connected to the internal combustion engine 100 as an exhaust system. The exhaust gas of the internal combustion engine 100 is purified by the three-way catalyst 114 and then discharged to the atmosphere through the muffler 115. An air-fuel ratio sensor 116 is attached upstream of the three-way catalyst 114.

  The rotation output portion of the internal combustion engine 100 is provided with crank angle detection means (rotation speed detection means) 119 for detecting the crank angle from the rotation angle of the crank angle detection gear 118 attached to the crankshaft 117.

  Sensor signals output from the flow rate detection means 105, the air-fuel ratio sensor 116, and the crank angle detection means 119 are each input to the control device 120 of the internal combustion engine.

  The internal combustion engine control device 120 is of a microcomputer type, and includes an MPU 121, a clock generation unit 122, a ROM 123, a RAM 124, a timer / counter 125, an I / O unit 126, an A / D conversion unit 127, a digital input unit 128, It has an analog input unit 129 and an output circuit unit 130, and performs fuel injection control, ignition timing control, diagnosis, and fuel property determination by software processing. That is, the control device 120 for the internal combustion engine also serves as a diagnostic device and a fuel property determination device.

  As the fuel injection control, the internal combustion engine control device 120 calculates the engine speed from the crank angle signal output from the crank angle detecting means 119, and according to the engine speed and the air amount measured by the flow rate detecting means 105. The basic fuel injection amount Ti is calculated, and the basic fuel injection amount Ti is set so that the air-fuel ratio of the air-fuel mixture supplied by the engine becomes a predetermined air-fuel ratio, for example, the stoichiometric air-fuel ratio by referring to the air-fuel ratio measured by the air-fuel ratio sensor 116. Is corrected (air-fuel ratio feedback control), and a fuel injection signal is output to the fuel injection valve 106.

  Further, the control device 120 of the internal combustion engine calculates the ignition timing according to the engine speed and the air amount as ignition timing control, and outputs an ignition timing signal to the ignition coil device 112.

  Next, an outline of one embodiment of the fuel property determination device for an internal combustion engine according to the present invention will be described with reference to FIG.

  As described above, the fuel property determination device according to the present embodiment is embodied in a software manner by the control device 120 of the internal combustion engine, and includes a time signal measurement unit 201, a fuel property determination parameter calculation unit 202, The fuel property determination parameter statistical processing unit 203, the fuel property determination execution permission unit 204, and the fuel property determination unit 205 are included.

  The time signal measuring means 201 measures the time required for the crankshaft 117 to rotate a predetermined angle from the crank angle signal output from the crank angle detecting means 119, and outputs a time signal indicating the measurement time.

  The fuel property determination parameter calculation unit 202 calculates a fuel property determination parameter from the time signal output from the time signal measurement unit 201. Based on the time signal, the fuel property determination parameter calculation means 202 generates a signal (two rotation components) generated every time the crankshaft 117 rotates twice, or a signal generated every time the crankshaft 117 rotates (one rotation component). Is detected, and the difference between the time signal at the time of the current ignition and the time signal at the time of the previous ignition of the engine speed is detected.

  The fuel property determination parameter statistical processing unit 203 detects a statistical property from the fuel property determination parameter calculated by the fuel property determination parameter calculation unit 202. For example, a parameter correlated with the kurtosis of the fuel property determination parameter distribution is calculated.

  The parameter that correlates with the kurtosis of the distribution of the fuel property determination parameter is the ratio or difference between the number of calculations of the fuel property determination parameter that is within the predetermined range and the number of calculations of the fuel property determination parameter that is outside the predetermined range.

  A slice level for determining a predetermined range for detecting a parameter correlated with the kurtosis of the distribution of the fuel property determination parameter is calculated from the rotational speed and load of the internal combustion engine, the water temperature, and the atmospheric pressure.

  The fuel property determination execution permission unit 204 selectively sets the permission to execute the fuel property determination based on the state of the internal combustion engine 100 or the like. For example, when the internal combustion engine 100 is idling, all the conditions are satisfied, that is, the engine water temperature is within a predetermined range, the environmental temperature is within a predetermined range, the battery voltage is within a predetermined range, the misfire determination is not performed, and the fuel property determination is not performed. Allow execution of judgments.

  The fuel property determination means 205 is provided with a statistical processing result from the fuel property determination parameter statistical processing means 203, for example, the distribution of the fuel property determination parameter, only when the fuel property determination execution permission means 204 gives permission to execute the fuel property determination. A parameter that correlates with kurtosis is input to determine the fuel property, that is, whether or not the fuel supplied to the internal combustion engine 100 is a heavy fuel.

  The fuel property determination means 205 determines that the fuel is heavy when the ratio or difference between the number of calculations of the fuel property determination parameter within the predetermined range and the number of calculations of the fuel property determination parameter outside the predetermined range is equal to or greater than a predetermined value. To do. The predetermined value for the heavy fuel determination is determined by the water temperature of the internal combustion engine 100.

  When the fuel property determining unit 205 determines that the fuel is heavy fuel, the diagnosis prohibiting unit 206 prohibits execution of a diagnosis (for example, a cooler strategy diagnosis) that is erroneously diagnosed due to the heavy fuel.

  When the fuel property determination unit 205 determines that the fuel is heavy fuel, the fuel control correction unit 207 corrects the fuel injection amount to be suitable for heavy fuel. When the fuel property determination unit 205 determines that the fuel is heavy, the ignition control correction unit 208 corrects the ignition timing to be suitable for the heavy fuel.

  3A and 3B show the time signal measured by the time signal measuring means 201 and its frequency spectrum. FIG. 3 (a) is for light fuel, and FIG. 3 (b) is for heavy fuel.

  Just by looking directly at the time signal, the difference between heavy and light is not known, but when looking at the frequency spectrum, the 0.5th order component (two rotation components) is You can see how the quality / lightness difference appears.

  Therefore, a filter for detecting this 0.5th order component is designed. Specifically, the fuel property determination parameter ROGHNS (i) calculated by Expression (1) is used. The calculation of the fuel property determination parameter ROGHNS (i) is performed by the fuel property determination parameter calculation means 202.

ROGHNS (i) =
2.TDATA (i-5) -2.TDATA (i-7) -TDATA (i-8) + TDATA (i-10) -TDATA (i-2) + TDATA (i-4) (1)
TDATA (i): Time required to rotate between predetermined angles (time signal)
TDATA (i-n): TDATA before n ignition

FIG. 4 shows the fuel property determination parameters calculated by the equation (1). (A) is for light fuel, and (b) is for heavy fuel.
It can be seen that the fuel property determination parameter varies in the case of heavy fuel than in the case of light fuel. The heavy fuel is literally in a state where the viscosity of the fuel is high, and its influence appears in the rotational pulsation via the fuel injection amount Ti. The fuel property is indirectly determined from the rotational pulsation. However, as can be seen from the frequency spectrum of FIG. 3, a heavy fuel cannot be used to obtain a signal with a significantly high intensity. The variation is large.

  Therefore, in the present embodiment, the statistical property of the fuel property determination parameter obtained by the equation (1) is detected, and the fuel property is determined based on this statistical property.

  In order to detect the statistical properties of the fuel property determination parameter, a distribution diagram of the fuel property determination parameter is shown in FIG. (A) is for light fuel, and (b) is for heavy fuel. A large variation in the fuel property determination parameter indicates that the standard deviation σ ′ at the time of heavy fuel is larger than the standard deviation σ at the time of light fuel. Therefore, a change in the standard deviation is captured. The process for capturing the change in standard deviation is shown below.

  As shown in FIG. 4, the slice level (upper limit S / L, lower limit −S / L) of the fuel property determination parameter is set, and the fuel property determination is between the upper limit S / L and the lower limit −S / L. The ratio (NUM / DEN) of the parameter (in-range parameter) calculation count DEN and the fuel property determination parameter (out-of-range parameter) calculation count NUM that is greater than or equal to S / L or less than -S / L is calculated.

As shown in FIGS. 5A and 5B, the standard deviation σ ′ for heavy fuel is larger than the standard deviation σ for light fuel, and the number of calculations DEN for the in-range parameter decreases when the fuel is heavy. The number of computations NUM for out-of-range parameters increases. Therefore, the ratio (NUM / DEN) increases. Changes in standard deviation can be detected by the ratio (NUM / DEN). When the ratio (NUM / DEN) exceeds a predetermined value that is a function of the water temperature, it is determined that the fuel is heavy. In terms of statistics, the ratio (NUM / DEN) is a parameter correlated (inversely proportional) to kurtosis.

  FIGS. 6A and 6B are distribution diagrams of actually measured fuel property determination parameters for light fuel and heavy fuel. When the processing described in FIG. 5 is performed, the ratio (NUM / DEN) is 0.549 when the fuel is light, and the ratio (NUM / DEN) is 1.034 when the fuel is heavy. Therefore, by setting the determination value to about 0.8, it is possible to determine heavy fuel / light fuel.

  FIG. 7 is a flowchart of a fuel property determination processing routine performed by the fuel property determination device according to the present embodiment. This fuel property determination processing routine is executed for each ignition.

  First, as an initial setting, the calculation counter is cleared (step 701).

  Next, a fuel property determination region is determined (step 702). As the determination conditions, all the conditions are satisfied that the engine water temperature is within the predetermined range, the environmental temperature is within the predetermined range, the battery voltage is within the predetermined range, the misfire determination is not performed, and the fuel property determination is not performed during the idling operation. Is determined as the fuel property determination region. This means that the fuel property determination execution permission unit 204 permits the fuel property determination.

  Next, slice levels S / L and -S / L are calculated from the engine speed, engine load, engine water temperature, and atmospheric pressure, and are set (step 703).

  Next, it is determined whether or not the fuel property determination parameter is between slice levels S / L and -S / L (step 704).

  When the fuel property determination parameter is between the slice levels S / L and -S / L, the in-range parameter calculation count (denominator) DEN is incremented (step 706).

  On the other hand, if the fuel property determination parameter is not between the slice levels S / L and -S / L, the out-of-range parameter calculation number (numerator) NUM is incremented (step 705).

  The calculation of the fuel property determination parameter will be described later with reference to the flowchart of FIG.

  Next, the ratio (NUM / DEN) is calculated (step 707), the calculation counter is incremented (step 708), and it is determined whether or not the calculation counter has reached a predetermined number of determinations (step 709).

  If the calculation counter has not reached the predetermined number of determinations, steps 702 to 708 are looped, and the calculation is executed again.

  On the other hand, when the operation counter reaches the predetermined number of determinations, the ratio (NUM / DEN) is compared with the determination value (step 710).

  If the ratio (NUM / DEN) <determination value, it is determined that the fuel is light (step 711). On the other hand, if the ratio (NUM / DEN) ≧ determination value, it is determined that the fuel is heavy (step 712).

  FIG. 8 is a flowchart of a fuel property determination parameter calculation processing routine. This routine is executed for each ignition.

  First, as the measurement of the time signal, the time required to rotate between predetermined crank angles (time signal TDATA (i)) is measured (step 801).

  Next, a fuel property determination parameter is calculated from equation (1) (step 802). After the calculation, the time signal is measured again in step 801, and the fuel property determination parameter is updated.

  FIG. 9 is a flowchart of the execution / prohibition processing routine of the cold machine strategy diagnosis in the present embodiment. This routine is executed for each scheduled task.

  First, it is determined whether or not the fuel property is determined to be heavy (step 901).

  When it is determined that the fuel property is not heavy (lightness determination), the diagnosis area determination of the cold machine strategy diagnosis is executed (step 902). If it is within the diagnosis area, a cold strategy diagnosis is executed (step 903). It is determined whether or not there is a surging of the engine speed by the cold machine strategy diagnosis.

  When it is determined that the fuel property is heavy, the execution of the cold engine strategy diagnosis is prohibited regardless of the cold engine strategy diagnosis area.

  As described above, when heavy fuel is used, the execution of cold strategy diagnosis is prohibited to prevent erroneous diagnosis.

  FIG. 10 is a flowchart of a fuel control processing routine of the control apparatus for an internal combustion engine according to the present invention. This routine is executed for each scheduled task.

  First, it is determined whether or not the fuel property is determined to be heavy (step 1001).

  If it is determined that the fuel property is not heavy (lightness determination), the correction coefficient is set to light data (step 1002). On the other hand, when it is determined that the fuel property is heavy, the correction coefficient is set to the data at the time of heavy (step 1003). Then, the fuel injection amount is calculated in consideration of the correction coefficient of the set data (step 1004).

  FIG. 11 is a flowchart of an ignition control processing routine of the control apparatus for an internal combustion engine according to the present invention. This routine is executed for each scheduled task.

  First, it is determined whether or not the fuel property is determined to be heavy (step 1101).

  If it is determined that the fuel property is not heavy (lightness determination), the correction coefficient is set to data for lightness (step 1102). On the other hand, when it is determined that the fuel property is heavy, the correction coefficient is set to the data at the time of heavy (step 1103). Then, the ignition timing is calculated in consideration of the correction coefficient of the set data (step 1104).

  FIG. 12 is a timing chart of fuel property determination of the fuel property determination device according to the present embodiment. The fuel property is determined when the ratio (NUM / DEN) is gradually calculated and reaches a predetermined number of calculations (here, 300 IGN, equivalent to 6 seconds). Referring to this result, the execution of the cold machine strategy diagnosis is prohibited.

  Since the exhaust gas reduction control is executed within a few seconds (about 20 seconds) after the start, the cooler strategy diagnosis is also executed within a few seconds after the start. Therefore, in order to prevent a misdiagnosis of the cold machine strategy diagnosis, it is necessary to determine the fuel property within a few seconds after starting. The determination timing of the fuel property determination of this embodiment is about 6 seconds after the start, which is a sufficient timing to prevent a false diagnosis of the cold machine strategy diagnosis. Further, when it is determined that the fuel is heavy, it is possible to correct the fuel injection amount and the ignition timing to improve drivability.

  From the above, the fuel property of the fuel used in the internal combustion engine can be determined in a few seconds immediately after the start (about 6 seconds in the case of 300IGN).

  To summarize the present embodiment, the fuel property determination parameter means 202 for calculating the fuel property determination parameter from the time signal detects the two rotation components and one rotation component of the engine speed, and the difference between the current time signal and the previous time signal. In the case of heavy fuel, its characteristics appear particularly in the two-rotation component. The heavy fuel is in a state where the viscosity of the fuel is high, and the influence thereof appears in the rotational pulsation via the fuel injection amount. This rotational pulsation is detected from the two rotational components of the engine speed.

  However, the feature does not appear remarkably, and the signal of the two-rotation component is such that the variation becomes large during heavy fuel.

  Therefore, the fuel property parameter statistical processing means 203 statistically processes the fuel property parameter and detects its characteristic. The statistical process is a process for detecting a parameter correlated with the kurtosis of the distribution of the fuel property determination parameter. The larger the parameter correlated with the kurtosis, the more the signal of the two rotation components varies. Therefore, it can be determined that the fuel is heavy.

  The parameter correlated with the kurtosis is calculated from the ratio or difference between the number of times the fuel property determination parameter is within the predetermined range and the number of times the fuel property determination parameter is outside the predetermined range. The fuel property determination means 205 determines that the fuel is heavy when the ratio or difference is equal to or greater than a predetermined value. If it is determined that the fuel property is heavy fuel, the execution of a diagnosis (for example, a cold machine strategy diagnosis) that is erroneously diagnosed at the time of heavy fuel is prohibited. As a further aspect, the fuel injection amount and the ignition timing are corrected when the heavy fuel is determined.

  As described above, the fuel property determination is promptly determined within a few hundred ignitions (within a few seconds after the start) of the internal combustion engine 100, and a diagnosis (for example, a cooler strategy diagnosis) is performed in the case of heavy fuel. By prohibiting it, it is possible to accurately prevent misdiagnosis. In addition, at the time of heavy fuel determination, the drivability at the time of heavy fuel can be improved by correcting the fuel injection amount and ignition timing to those suitable for heavy fuel.

  Next, detailed features of the present embodiment will be listed.

  (1) Only when the fuel property determination execution permission unit 204 is permitted to execute the fuel property determination, for example, when the internal combustion engine 100 is idling, the engine water temperature is within a predetermined range, the environmental temperature is within a predetermined range, and the battery voltage is Since the fuel property determination means 205 determines the fuel property only when all the conditions are met within the predetermined range where the misfire determination has not been performed and the fuel property determination has not been performed, an erroneous determination of the fuel property has occurred. Avoided.

  (2) The fuel property determination parameter statistical processing means 203 is a parameter correlated with the kurtosis of the distribution of the fuel property determination parameter, and the number of calculations of the fuel property determination parameter within a predetermined range and the fuel outside the predetermined range By using the ratio or difference of the number of calculation times of the property determination parameter, the accuracy of heavy fuel determination is improved. Further, the heavy fuel determination is performed by calculating the slice level for determining the predetermined range for detecting the parameter correlated with the kurtosis of the distribution of the fuel property determination parameter from the rotational speed and load of the internal combustion engine, the water temperature, and the atmospheric pressure. Accuracy is further improved.

  (3) The fuel property determination means 205 is heavy when the ratio or difference between the number of calculations of the fuel property determination parameter within the predetermined range and the number of calculations of the fuel property determination parameter outside the predetermined range is greater than or equal to a predetermined value. Since it is determined that the fuel is used, it is possible to perform heavy fuel determination with high accuracy. Furthermore, by determining the predetermined value for heavy fuel determination by the fuel property determination means 205 based on the water temperature of the internal combustion engine 100, the accuracy of heavy fuel determination is further improved.

1 is a configuration diagram showing one embodiment of an internal combustion engine system to which a fuel property determination device for an internal combustion engine and a control device for an internal combustion engine according to the present invention are applied. 1 is a block diagram showing one embodiment of a fuel property determination device for an internal combustion engine and a control device for the internal combustion engine according to the present invention. (A), (b) is a graph which shows the time signal and frequency spectrum at the time of light fuel and heavy fuel. (A), (b) is a graph which shows the fuel property determination parameter at the time of light fuel and heavy fuel. (A), (b) is a distribution map of the fuel property determination parameter at the time of light fuel and heavy fuel. (A), (b) is the distribution map of the fuel property determination parameter at the time of the light fuel and the heavy fuel which were actually measured. The flowchart of the fuel property determination processing routine which the fuel property determination apparatus by this embodiment performs. The flowchart of the fuel property determination parameter calculation process routine in a fuel property determination process routine. The flowchart of the execution / prohibition process routine of the cold machine strategy diagnosis by this embodiment. The flowchart of the fuel control processing routine of the control apparatus of the internal combustion engine by this invention. It is a flowchart (4) of this invention. The flowchart of the ignition control processing routine of the control apparatus of the internal combustion engine by this invention. It is a flowchart (5) of this invention. The timing chart of the fuel property determination of the fuel property determination apparatus by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Internal combustion engine 101 Combustion chamber 102 Air cleaner 103 Throttle valve 104 Intake manifold 105 Flow rate detection means 106 Fuel injection valve 107 Fuel tank 108 Fuel pump 109 Pressure regulator 110 Fuel pipe 111 Spark plug 112 Ignition coil device 113 Exhaust pipe 114 Three-way catalyst 115 Muffler 116 Air-fuel ratio sensor 117 Crankshaft 118 Crank angle detection gear 119 Crank angle detection means 120 Internal combustion engine controller 121 MPU
122 Clock generator 123 ROM
124 RAM
125 timer / counter 126 I / O unit 127 A / D conversion unit 128 digital input unit 129 analog input unit 130 output circuit unit 201 time signal measurement unit 202 fuel property determination parameter calculation unit 203 fuel property determination parameter statistical processing unit 204 fuel property Determination execution permitting means 205 Fuel property determining means 206 Diagnosis prohibiting means 207 Fuel control correcting means 208 Ignition control correcting means

Claims (11)

A time signal measuring means for measuring a time required for the crankshaft of the internal combustion engine to rotate at a predetermined angle and outputting a time signal indicating the measurement time;
From the time signal output from the time signal measuring means, a two-rotation component signal generated each time the crankshaft rotates twice or a one-rotation component signal generated every time the crankshaft rotates one time is detected, and the two rotations A fuel property determination parameter calculating means for calculating a fuel property determination parameter which is a difference between a time signal at the time of current ignition and a time signal at the time of previous ignition of the component signal or the one rotation component signal ;
And fuel property determination parameter statistical processing means for detecting a parameter correlating to the kurtosis of the distribution of the statistical nature of the fuel property determination parameter computed by the fuel property determination parameter calculating means,
Fuel property determination means for determining the fuel property used in the internal combustion engine based on a parameter correlated with the kurtosis of the distribution ;
A fuel property determination apparatus for an internal combustion engine, comprising:   Fuel property determination execution permission means for selectively setting execution permission of fuel property determination, and when the fuel property determination execution permission means permits the execution of fuel property determination, the fuel property determination means determines the fuel property. The fuel property determination device for an internal combustion engine according to claim 1, wherein the determination is made.   The fuel property determination execution permission means executes a fuel property determination in which the internal combustion engine is idling, the engine water temperature is within a predetermined range, the environmental temperature is within a predetermined range, the battery voltage is within a predetermined range, and misfire determination is not performed. 3. The fuel property determination apparatus for an internal combustion engine according to claim 2, wherein execution of the determination is permitted when all the conditions are satisfied. The parameter correlated with the kurtosis of the distribution of the fuel property determination parameter is a ratio or difference between the number of calculations of the fuel property determination parameter within a predetermined range and the number of calculations of the fuel property determination parameter outside the predetermined range. The fuel property determining apparatus for an internal combustion engine according to claim 1 , wherein The slice level for determining the predetermined range for detecting a parameter correlated with the kurtosis of the distribution of the fuel property determination parameter is calculated from the rotational speed and load of the internal combustion engine, the water temperature, and the atmospheric pressure. 5. The fuel property determination device for an internal combustion engine according to 4 . The fuel property determination means is configured to output heavy fuel when the ratio or the difference between the number of calculations of the fuel property determination parameter within the predetermined range and the number of calculations of the fuel property determination parameter outside the predetermined range is equal to or greater than a predetermined value. The fuel property determination apparatus for an internal combustion engine according to claim 4 or 5 , wherein The fuel property determination device for an internal combustion engine according to claim 6 , wherein the predetermined value for heavy fuel determination by the fuel property determination means is determined by a water temperature of the internal combustion engine. The fuel property determination device for an internal combustion engine according to any one of claims 1 to 7, further comprising diagnosis prohibition determination means for prohibiting determination diagnosis based on a determination result of the fuel property determination means. When the fuel property determination means of the fuel property determination device according to any one of claims 1 to 8 determines that the fuel is heavy, prohibiting a diagnosis that may be erroneously determined when the fuel is heavy. A control device for an internal combustion engine characterized by the above. When the fuel property determination means of the fuel property determination device according to any one of claims 1 to 8 determines that the fuel is heavy fuel, the fuel control is corrected to be suitable for the heavy fuel. Control device for internal combustion engine. When the fuel property determination means of the fuel property determination device according to any one of claims 1 to 8 determines that the fuel is heavy fuel, the ignition control is corrected to be suitable for the heavy fuel. Control device for internal combustion engine.

Images