JP2006161686A - Fuel characteristic determination device for internal combustion engine and fuel device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize fuel characteristic determination without an erroneous determination with applying a means used in a conventional internal combustion engine without adding a special sensor or the like. <P>SOLUTION: Characteristics of fuel is determined by a fuel characteristic determination means 106 from ignition timing correction quantity for suppressing rotation fluctuation at a time of idling by ISC means, and fuel quantity is corrected based on the determination result. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel property determination device and a fuel control device for an internal combustion engine used in a vehicle such as an automobile, and more particularly to a fuel property determination applied to air-fuel ratio control of an internal combustion engine when the fuel properties are different between winter and summer. The present invention relates to a device and a fuel control device.

  The properties of gasoline fuel used in internal combustion engines are not necessarily constant due to the natural evaporation of low boiling point volatile components in the fuel components. For this reason, gasoline fuel is a normal fuel containing a low boiling point volatile component equivalent to the standard amount due to changes over time, that is, a low-quality fuel and a component that has a low residual amount of low boiling point volatile components due to natural evaporation and is less volatile than normal fuel. And heavy fuel containing a lot.

  For this reason, the fuel properties may differ between winter and summer, and it is necessary to perform fuel control (air-fuel ratio control) of the internal combustion engine in accordance with the fuel properties. In order to perform this fuel control, it is necessary to determine the properties of the fuel used in the internal combustion engine.

  As a conventional technique for determining fuel properties, a change in engine speed is detected when the idling speed after starting the internal combustion engine is within a predetermined value range, and a determination is made as to whether or not the speed fluctuation at that time is equal to or greater than a predetermined value. There is a fuel property determination device that determines that the fuel is heavy if the fluctuation in the rotational speed is equal to or greater than a predetermined value (for example, Patent Document 1).

  However, such a conventional fuel property determination device does not take into account the change over time in the friction of the internal combustion engine. For this reason, for example, as compared with a case where the internal combustion engine is unused and new, the friction of the internal combustion engine is reduced after use after traveling to some extent, and as a result, the fluctuation of the engine speed becomes small. Therefore, there is a possibility that the fuel property is erroneously determined.

JP 2003-214243 A

  The problem to be solved by the present invention is to perform fuel property determination without erroneous determination, and further to perform fuel property determination without erroneous determination in a conventional internal combustion engine system without adding a special sensor or the like. It is to realize by applying the means.

  An internal combustion engine fuel property determination apparatus according to the present invention controls an ignition timing control means for controlling an ignition timing of an internal combustion engine, and controls an idling rotational speed of the internal combustion engine to a predetermined target rotational speed by ignition timing control by the ignition timing control means. And means for determining the fuel property from a control amount for controlling the idling speed to a predetermined target speed by the ignition timing control means.

  The means for determining the fuel property performs frequency analysis on the amount of change in the control amount that controls the idling speed by ignition timing control, determines the fuel property from the frequency analysis result, or determines the idling speed by ignition timing control. The change amount of the controlled variable to be controlled is filtered by one or more band pass filters, and the fuel property is determined from the filtered value by the band pass filter.

  The fuel control device for an internal combustion engine according to the present invention includes means for performing fuel correction according to the fuel property determined by the fuel property determination device.

  Further, another fuel control device of the internal combustion engine according to the present invention includes means for calculating a correction coefficient according to the fuel property determined by the fuel property determination device, and means for performing fuel correction at start-up by the correction coefficient. Have.

  Furthermore, another fuel control apparatus for an internal combustion engine according to the present invention includes means for calculating a correction coefficient according to the fuel property determined by the fuel property determination device, and means for performing fuel correction at the time of acceleration using the correction coefficient. And having.

  When the fuel is heavy, undulation on the low frequency side occurs in the idling rotational speed. Therefore, undulation on the low frequency side also occurs in the ignition correction amount (control amount) for correcting the ignition timing. On the other hand, when the fuel is light, undulation on the high frequency side occurs in the idling speed, and undulation on the high frequency side also occurs in the ignition correction amount (control amount) for correcting the ignition timing. The fuel property determination apparatus for an internal combustion engine according to the present invention detects the size and singularity of the swells in these frequency bands, and determines the fuel property.

  Since each frequency band fluctuation amount of the ignition timing correction amount for idling speed control is determined by the magnitude of the power spectrum by frequency analysis or filtering of a plurality of bandpass filters, the internal combustion engine friction has a DC component offset. Therefore, this determination is not affected.

  The determined fuel property can be reflected in the next fuel injection amount by storing it in a backed up volatile memory.

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

  FIG. 1 shows an embodiment of a control device for an internal combustion engine provided with a fuel property determination device as an object of the present invention.

  The control device includes engine speed calculation means 101, basic fuel calculation means 102, basic fuel correction coefficient calculation means 103, basic ignition timing calculation means 104, ISC (Idle Speed Control) means 105, and fuel property determination means. (Apparatus) 106, air-fuel ratio feedback control coefficient calculation means 107, target air-fuel ratio setting means 108, basic fuel correction means 109, and ignition timing correction means 110.

  The engine speed calculation means 101 counts the electrical signal output from the crank angle sensor 207 (see FIG. 2) set at a predetermined crank angle position of the internal combustion engine, mainly the number of inputs per unit time of the pulse signal change. Then, the number of revolutions per unit time of the internal combustion engine (engine revolution number) is calculated from the sensor signal cycle by performing arithmetic processing.

  The basic fuel calculation means 102 uses the engine speed calculated by the engine speed calculation means 101 and the intake pipe pressure detected by the intake pipe pressure sensor 205 (see FIG. 2) installed in the intake pipe of the internal combustion engine. As a load, the basic fuel amount of the internal combustion engine in each operation region is calculated.

  The basic fuel correction coefficient calculation means 103 calculates the basic fuel amount calculated by the basic fuel calculation means 102 based on the engine load calculated from the engine speed calculated by the engine speed calculation means 101 and the intake pipe pressure. A correction coefficient (basic fuel correction coefficient) in each operating region of the internal combustion engine is calculated.

  The basic ignition timing calculation means 104 determines an optimal ignition timing in each region of the internal combustion engine by map search or the like based on the engine speed and the engine load from the intake pipe pressure.

  The ISC means 105 calculates a target engine speed at idling for keeping the idling engine speed constant from the engine speed and the engine water temperature detected by the water temperature sensor 209 (see FIG. 2), and outputs the target engine speed to the ISC valve controller 119. The target intake air flow to be performed and the ISC ignition timing correction amount output to the ignition timing correction auxiliary means 110 are calculated. This ISC ignition timing correction amount is a control amount for controlling the idling speed by ignition timing control.

  The fuel property determination means 106 performs frequency analysis of the signal of the ISC ignition timing correction amount output from the ISC means 105, and determines the properties of the fuel, such as heavy / light, taking into account the engine water temperature.

  The air-fuel ratio feedback control coefficient calculation means 107 is supplied to the internal combustion engine from the output of the oxygen concentration sensor 210 (see FIG. 2) set in the exhaust pipe of the internal combustion engine, the engine load from the intake pipe pressure, and the engine water temperature. An air-fuel ratio feedback control coefficient by PID control is calculated so that the fuel-air mixture is maintained at a target air-fuel ratio described later.

  In the present embodiment, the oxygen concentration sensor outputs a signal proportional to the exhaust air / fuel ratio. However, the exhaust gas has two rich / lean exhaust gases with respect to the stoichiometric air / fuel ratio. There is no problem even if it outputs a signal.

  The target air-fuel ratio setting means 108 determines an optimum target air-fuel ratio in each region of the internal combustion engine by map search or the like based on the engine load from the engine speed and the intake pipe pressure. The target air-fuel ratio determined by the target air-fuel ratio setting means 108 is output to the air-fuel ratio feedback control coefficient calculation means 107 and used for air-fuel ratio feedback control.

  The basic fuel correction means 109 calculates the basic fuel amount calculated by the basic fuel calculation means 102, the basic fuel correction coefficient calculated by the basic fuel correction coefficient calculation means 103, the engine water temperature, and the fuel property by the fuel property determination means 106. A correction calculation is performed based on the determination value and the air-fuel ratio feedback control coefficient calculated by the air-fuel ratio feedback control coefficient calculation means 107, and the injection command signal Tout based on the corrected fuel amount is used as the fuel injection means 111, 112, 113, To 114.

  The ignition timing correction supplement means 110 corrects the ignition timing searched by the basic ignition timing calculation means 104 based on the state of the internal combustion engine (transient or steady) and the ISC ignition timing correction amount output by the ISC means 105, An ignition timing command signal ADV based on the corrected ignition timing is output to the ignition means 115, 116, 117, 118 of each cylinder.

  In this embodiment, the engine load is represented by the pressure of the intake pipe, but may be represented by the amount of air taken in by the internal combustion engine.

  FIG. 2 shows an example of a hardware configuration of an internal combustion engine controlled by a fuel control device including a fuel property determination device that is an object of the present invention.

  The internal combustion engine 201 includes a throttle throttle valve 202 that detects the amount of air to be sucked in, a throttle opening sensor 217 that detects the opening of the throttle throttle valve 202, and a flow path that bypasses the throttle throttle valve 202 and is connected to the intake pipe 204. An idle speed control valve (ISC valve) 203 that controls the rotational speed of the internal combustion engine 201 during idle operation, an intake pipe pressure sensor 205 that detects the pressure in the intake pipe 204, and fuel. A fuel injection valve 206 to be injected, a crank angle sensor 207 set at a predetermined crank angle position of the internal combustion engine 201, an ignition plug 213 for igniting a fuel mixture supplied into a cylinder of the internal combustion engine 201, An ignition module 208 that supplies ignition energy to the spark plug 213 based on the ignition signal of the engine controller 250 Having.

  The fuel injection valve 206 corresponds to the fuel injection means 111 to 114 for each cylinder in FIG. 1, and the spark plug 213 corresponds to the ignition means 115 to 118 for each cylinder in FIG. The ISC valve 203 corresponds to the ISC valve control means 119 in FIG.

  The internal combustion engine 201 further includes a water temperature sensor 209 that is set in the cylinder block 214 of the internal combustion engine 201 to detect the cooling water temperature of the internal combustion engine 201, and an oxygen concentration in the exhaust gas that is set in the exhaust pipe 215 of the internal combustion engine 201. The oxygen concentration sensor 210 to detect, the swirl control means 211 for turning on / off the notched valve 216 set in the intake pipe 204 of the internal combustion engine 201, and a main switch for operating and stopping the internal combustion engine 201. An ignition key switch 212 and a computer-type engine control device 250 for controlling each auxiliary device of the internal combustion engine 201 are provided.

  As described above, the oxygen concentration sensor 210 outputs a signal proportional to the exhaust air / fuel ratio in this embodiment, but the exhaust gas is richer than the stoichiometric air / fuel ratio. There is no problem even if it outputs two signals on the lean side.

  The idling speed of the internal combustion engine is controlled by the ISC valve 203. However, when the throttle throttle valve 202 is controlled by a motor or the like, the idle speed control can be performed by the throttle throttle valve 202. The ISC valve 203 is unnecessary. Further, in this embodiment, the fuel control is established by detecting the intake pipe pressure, but the fuel control is similarly established even if the intake air amount of the internal combustion engine is detected.

  FIG. 3 shows an example of an internal configuration of an engine control device 250 including a fuel property determination device that is an object of the present invention.

  The engine control device 250 converts an electrical signal of each sensor installed in the internal combustion engine 201 into a signal for digital calculation processing, and converts the control signal for digital calculation into an actual actuator drive signal. The state of the internal combustion engine 201 is determined from the digital arithmetic processing signals from the / O driver 301 and the I / O driver 301, and the fuel amount and ignition timing required by the internal combustion engine are calculated based on a predetermined procedure. An arithmetic unit (MPU) 302 that outputs the calculated value to the I / O driver 301, a non-volatile memory 303 such as an EP-POM that stores control procedures and control constants of the arithmetic unit 302, and an arithmetic unit 302 It is comprised from the volatile memory 304 by RAM etc. which store the calculation result of these.

  The engine control device 250 performs the above-described engine speed calculation means 101, basic fuel calculation means 102, basic fuel correction coefficient calculation means 103, basic ignition timing calculation means 104, ISC by software processing in which the arithmetic device 302 executes a computer program. Means 105, fuel property determination means 106, air-fuel ratio feedback control coefficient calculation means 107, target air-fuel ratio setting means 108, basic fuel correction means 109, and ignition timing correction means 110 are embodied.

  The volatile memory 304 may be connected to a backup power supply for the purpose of storing memory contents even when the ignition key switch 212 is off and power is not supplied to the engine control device 250.

  In this embodiment, the engine control device 250 inputs signals from the water temperature sensor 209, the crank angle sensor 207, the oxygen concentration sensor 210, the intake pipe pressure sensor 205, the throttle opening sensor 217, and the ignition key switch 212, and The cylinder fuel injection command signal is output to 1-4 cylinder fuel injection means 111-114, the ignition command signal of each cylinder is output to 1-4 cylinder ignition means 115-118, and the ISC valve opening command signal is the ISC valve. It outputs to the control means 119, and outputs the swirl control valve drive signal for stabilizing the cold start to the swirl control means 211.

  FIG. 4 shows a state in which the fuel wall flow stays in the intake passage of the internal combustion engine equipped with the control device of the present embodiment.

  The fuel injected from the fuel injection valve 206 into the intake passage 401 is divided into a wall flow zone Fb that stays in the wall flow Fa adhering to the wall surface of the intake passage 401 and a wall flow separation Fc that leaves the wall flow Fa. Separated.

  Then, the direct inflow Fd and the wall flow separation Fc that the fuel injected from the fuel injection valve 206 directly flows into the cylinder chamber (combustion chamber) flow into the cylinder chamber as the actual inflow fuel Fe and participate in actual combustion. Will be.

  When the fuel property is heavy, the wall flow retention Fb is large and the wall flow separation Fc is small. On the other hand, when the fuel property is light, the opposite, that is, the wall flow retention Fb is small and the wall flow separation Fc is large.

  Formula (1) represents an example of a calculation formula for the amount of injected fuel. The basic fuel injection amount TP is multiplied by the post-startup increase correction coefficient KAS and the water temperature correction coefficient KTW, and the injector invalid injection width TS is added to obtain the injected fuel amount Tout.

      Tiout = TP · KAS · KTW + TS (1)

  FIG. 5 shows an example of setting of the post-startup increase correction coefficient KAS. The increase correction coefficient after start-up attenuates with the elapsed time after start-up and converges to 1.0. Line KASH is a set value for heavy fuel, and line KASl is a set value for light fuel. Since heavy fuel has a large wall flow, the post-startup increase correction coefficient KAS is set larger than that of light fuel.

  FIG. 6 shows an example of setting the water temperature correction coefficient KTW. Line KTWh is a set value for heavy fuel, and line KTWl is a set value for light fuel. Similar to the post-startup increase correction coefficient in FIG. 5, the water temperature correction coefficient KTW for heavy fuel is set larger than that for light fuel.

  FIG. 7 shows an example of the behavior of HC discharged at start-up. Line HCh shows the HC emission characteristics when starting with light fuel with the setting of the post-startup increase correction coefficient KASh and water temperature correction coefficient KTWh for heavy fuel. Line HCl indicates the HC emission characteristics when starting with light fuel with the setting of the post-startup increase correction coefficient KASl and water temperature correction coefficient KTWl in the case of light fuel.

  In the case of heavy fuel, the amount of injected fuel is set to be large, so when starting with light fuel with fuel control characteristics suitable for heavy fuel, a large amount of HC is discharged and the amount of HC emitted It becomes difficult to keep the value within the exhaust gas regulation value.

  FIG. 8 shows an example of the engine speed behavior at the start. Line NEl shows the engine speed characteristics when starting with heavy fuel with the setting of the post-startup increase correction coefficient KASl and the water temperature correction coefficient KTWl in the case of light fuel. Line NEh shows the engine speed characteristics when starting with heavy fuel with the setting of the post-startup increase correction coefficient KASh and the water temperature correction coefficient KTWh in the case of heavy fuel.

  Since the heavy fuel start-up fuel needs to be set to be larger than the light fuel, the post-start-up increase correction coefficient KASl and the water temperature correction coefficient KTWl set for the light fuel will cause poor rotation rise at start-up. It can be seen that it occurs.

  FIG. 9 shows an example of the relationship between engine torque and ignition timing during idling. The symbol ITs is a set basic ignition timing, and the torque decreases on the retard side from the basic ignition timing, and the torque increases within a predetermined range on the advance side.

  FIG. 10 shows an example of ISC control logic by the ISC means 105. In processing block 1001, a table search for the target engine speed at idling is performed from the engine water temperature. Then, the adder 1002 obtains a difference between the current idling speed (detected value of idling speed) and the target speed obtained by table search in the processing block 1001. The ISC valve control is performed so as to reduce this difference, and the ignition timing correction amount is retrieved in the processing block 1003 to correct the ignition timing.

  In this ISC ignition timing control, when the target rotational speed during idle operation is higher than the detected value of idling rotational speed, the ignition timing is set to the advance side, and the target rotational speed during idle operation is detected value of idling rotational speed. When it is lower, the ignition timing is set to the retard side.

  FIG. 11 shows an example of the behavior of the idling speed and the ignition timing correction amount. The engine speed fluctuates as shown by the line NEr with respect to the set idle target speed NEi. On the other hand, the ignition timing is corrected as indicated by line ITr in order to suppress fluctuations in the engine speed with respect to the set basic ignition timing ITb.

  FIG. 12 shows an example of a power spectrum for frequency analysis of the ISC ignition timing correction amount. The power spectrum Sh appears in the ISC ignition timing correction amount (control amount) for heavy fuel, and the power spectrum Sl appears in the ISC ignition timing correction amount (control amount) for light fuel. .

  In other words, since the undulation at low frequency of the idling speed increases when heavy fuel is used, the ISC ignition timing correction amount also has a power spectrum Sh on the low frequency side. Since the undulation at a certain number of high frequencies increases, the power spectrum S1 also appears on the high frequency side of the ISC ignition timing correction amount accordingly.

  FIG. 13 shows an example of the control logic of the fuel property determination means 106 according to the present invention. First, the AND circuit 1301 determines whether all conditions of the water temperature condition, the internal combustion engine rotation condition, and the idle state are satisfied.

  When all the conditions are satisfied, the switch 1302 is turned on, and the ISC ignition correction amount (control amount) is input to the frequency analysis unit 1303 for frequency analysis. Thereafter, a power spectrum detector 1304 detects a specific power spectrum, and a processing block 1305 searches for a base correction coefficient based on the degree of heavy / light fuel based on the frequency characteristics and size of the power spectrum.

  Thus, as shown in FIG. 12, the fuel property determination means 106 according to the present embodiment increases the undulation at low frequencies of idle rotation when heavy fuel is used. By utilizing the fact that the power spectrum Sh appears on the low frequency side of the ignition timing correction amount, the fuel property correction suitable for the degree of heavy / light fuel is obtained from the frequency characteristics and size of the power spectrum of the ISC ignition timing correction amount. It is characterized by calculating a base correction coefficient.

  In processing blocks 1306 to 1308, weighted average processing is performed. The base correction coefficient is weighted and averaged in the present processing blocks 1306 to 1308, and is output to the basic fuel correction means 109 (see FIG. 1) as the fuel property correction coefficient KFU.

  In the present embodiment, the weighted average weight is a fixed number, but may be a table search variable based on engine water temperature or the like.

  Thereby, the friction of the internal combustion engine becomes a direct current offset in each frequency band fluctuation amount of the ISC ignition timing correction amount, and the fuel property determination without erroneous determination can be performed. Moreover, without adding a special sensor or the like, the fuel property determination without erroneous determination is performed using the ISC ignition timing correction value (control amount) of the ISC means 105 used in the conventional internal combustion engine system.

  The fuel property, the fuel property correction coefficient KFU and the like determined by this control logic are stored in a backed up volatile memory and reflected in the correction of the basic fuel amount at the next start.

  FIG. 14 shows an example of data acquisition for frequency analysis of the present embodiment. The ISC ignition timing correction values at regular intervals as in the interval A are sampled in an overlapping manner as in the data strings Da, Db, and Dc, and subjected to frequency analysis in the order indicated by n. Note that there is no problem even if the frequency analysis is performed only on the data string Da.

  FIG. 15 shows another example of the control logic of the fuel property determination means 106 according to the present invention. Also in this case, first, the AND circuit 1401 determines whether or not all of the water temperature condition, the internal combustion engine rotation condition, and the idle state are satisfied.

  When all the conditions are satisfied, the switch 1402 is turned on, and the ISC ignition correction amount (control amount) is input to the band-pass filters 1403 to 1405 constituted by digital filters. One of the output values (filtering values) of the bandpass filters 1403 to 1405 is selected by the switch 1406 according to the engine water temperature. Based on the selected bandpass filter output value, a processing block 1407 searches for a base correction coefficient according to the degree of heavy / light fuel.

  As described above, the fuel property determination means 106 according to the present embodiment uses the filtering value of one band-pass filter 1403, 1404 or 1405 selected according to the engine water temperature, so that the fuel suitable for the degree of heavy / light fuel. It is characterized in that a base correction coefficient for property correction is calculated.

  In processing blocks 1408 to 1410, weighted average processing is performed. The base correction coefficient is weighted and averaged in the processing blocks 1408 to 1410, and is output to the basic fuel correction means 109 (see FIG. 1) as the fuel property correction coefficient KFU.

  In this case as well, as in the example of FIG. 13 described above, the weighted average weight is a fixed number, but may be a table search variable based on engine water temperature or the like.

  Also in this case, the friction of the internal combustion engine has a direct current offset in each frequency band fluctuation amount of the ISC ignition timing correction amount, so that it is possible to perform fuel property determination without erroneous determination, and a special sensor or the like can be used. Without addition, fuel property determination without erroneous determination is performed using the ISC ignition timing correction value of the ISC means 105 used in the conventional internal combustion engine system.

  In addition, the fuel property and the fuel property correction coefficient KFU determined by this control logic are stored in the backed up volatile memory as in the above example of FIG. 13, and the basic fuel amount at the next start-up is stored. It will be reflected in the correction.

  FIG. 16 shows an example of fuel correction at start-up by the fuel property correction coefficient output by the fuel property determination means of the present invention. The basic fuel amount TP is corrected by the post-startup increase correction coefficient KAS in the processing block 1501, and further, the water temperature correction coefficient KTW is corrected in the processing block 1502.

  Thereafter, the corrected fuel amount is multiplied by the multiplier 1504 by the fuel property correction coefficient KFU output from the fuel property determining means 106 and output as the injected fuel amount Tout. In this fuel property correction, the fuel correction on the rich side is performed in the heavy state, and the fuel correction on the lean side is performed in the light state.

  FIG. 17 shows another example of fuel correction at start-up by the fuel property correction coefficient output by the fuel property determination means of the present invention. The post-startup increase correction coefficient KAS output from the processing block 1601 is multiplied by the fuel property correction coefficient KFU1 output from the first fuel property determination means 106-1, and is subjected to fuel property correction. The fuel property correction is also performed on the rich side in the heavy state and on the lean side in the light state.

  The water temperature correction coefficient KTW output from the processing block 1604 is multiplied by the fuel property correction coefficient KFU2 output from the second fuel property determination means 106-2 by the multiplier 1606, and is subjected to fuel property correction. The fuel property correction is also performed on the rich side in the heavy state and on the lean side in the light state.

  The post-startup increase correction coefficient KASc and the water temperature correction coefficient KTWc, each of which has been subjected to fuel property correction, correct the basic fuel amount TP by the multiplier 1607 and are output as the injected fuel amount Tout.

  In the example of FIG. 17, the fuel property determination means is provided for each of the post-startup increase and the water temperature correction coefficient, compared to the above-described example of FIG. 16.

  FIG. 18 shows an example in which the fuel property correction is applied to the acceleration increase at the time of acceleration of the internal combustion engine. In the processing block 1701, the throttle opening, the engine speed and the engine water temperature are input, the acceleration increase correction coefficient KAC is calculated from these input data, and the acceleration increase correction coefficient KAC is output.

  The acceleration increase correction coefficient KAC is multiplied by the fuel property correction coefficient KFU output from the fuel property determination means 106 by the multiplier 1703 and subjected to fuel property correction.

  After that, the acceleration increase correction coefficient KACc after the fuel property correction is applied as an acceleration increase correction to the injected fuel amount Tout by the multiplier 1704, and is output to the fuel injection valve as the injected fuel amount Tiac after the acceleration increase correction.

  FIG. 19 shows an example of obtaining the acceleration increase correction coefficient KAC. The difference in the throttle opening is calculated by a delay unit 1801 and an adder 1802 per predetermined time. Based on the difference and the engine speed, a map search is made for an acceleration increase coefficient in processing block 1803. Further, in a processing block 1804, a table search is performed for the water temperature correction coefficient of the acceleration increase coefficient based on the engine water temperature. The multiplier 1805 corrects the acceleration increase correction coefficient with the water temperature correction coefficient, and outputs the acceleration increase correction coefficient KAC.

  FIG. 20 shows an example of a detailed flowchart of the control procedure of the fuel control device provided with the fuel property determining means of the present invention.

  In step 2001, the engine speed calculated from the input crank angle sensor signal is read. In step 2002, the engine load is read. In step 2003, the basic fuel amount is calculated from the engine speed and the engine load.

  In step 2004, the basic fuel correction coefficient is searched based on the engine speed and the engine load. In step 2005, the target air-fuel ratio is searched based on the engine speed and the engine load. In step 2006, the output signal of the oxygen concentration sensor is read. In step 2007, the air-fuel ratio feedback control coefficient is calculated from the oxygen concentration sensor signal, the target air-fuel ratio, the engine speed, and the engine load.

  In step 2008, the target rotational speed (ISC target rotational speed) during idle operation is calculated from the engine rotational speed and the engine water temperature. In step 2009, the target intake air amount (ISC target flow rate) during idle operation is calculated from the ISC target rotational speed. In step 2010, the ISC ignition timing correction amount is calculated based on the engine speed and the ISC target speed.

  In step 2011, the ISC ignition timing correction amount is sampled and frequency analysis is performed. In step 2012, the fuel property is determined from the power spectrum of the frequency analysis, and the fuel property correction coefficient is calculated.

  In step 2013, the basic fuel amount is corrected by the basic fuel correction coefficient, the fuel property correction coefficient, the post-startup increase correction coefficient, the water temperature correction coefficient, and the like, and the injected fuel amount is calculated. In step 2014, the basic ignition timing is calculated from the engine speed and the engine load. In step 2015, the basic ignition timing is corrected with an ISC ignition timing correction amount or the like.

  FIG. 21 shows an example of a detailed flowchart of the control procedure of the fuel property determination means according to the embodiment shown in FIG.

  In steps 2101 to 2103, it is determined whether an engine water temperature condition, an engine speed condition, and an idle state are established. If even one of the conditions is not satisfied, the present control is not performed, and only when all the conditions are satisfied, the process proceeds to step 2104 to read the ISC ignition timing correction amount.

  In step 2105, it is determined whether or not the read ISC ignition timing correction amount is a data amount necessary for frequency analysis. If the data amount is complete, the process proceeds to step 2106 to perform frequency analysis of the ISC ignition timing correction amount. .

  In step 2107, a specific power spectrum of the frequency analysis result is detected. In step 2108, a fuel property correction coefficient is searched from the specific power spectrum, and in step 2109, a weighted average of the values is performed.

  FIG. 22 shows an example of a detailed flowchart of the control procedure of the fuel property judging means according to the embodiment shown in FIG.

  In steps 2201 to 2203, it is determined whether the engine water temperature condition, the engine speed condition, and the idle state are established. If even one of the conditions is not satisfied, the present control is not performed, and only when all the conditions are satisfied, the process proceeds to Step 2204 to read the ISC ignition timing correction amount.

  In step 2205, the ISC ignition timing correction amount is individually subjected to filter processing using a plurality of bandpass filters. In step 2206, one bandpass filter is selected from a plurality of bandpass filters according to the engine water temperature, and a predetermined filtering value is selected. In step 2207, a fuel property correction coefficient is searched based on the selected filtering value, and in step 2208, a weighted average is applied to the value.

  FIG. 23 shows an example of a detailed flowchart of fuel correction by the fuel property correction coefficient in the embodiment shown in FIG.

  In step 2301, the basic fuel amount is read. In step 2302, the post-startup increase correction coefficient is read. In step 2303, correction is performed by multiplying the basic fuel amount by the post-startup increase correction coefficient. In step 2304, a water temperature correction coefficient is read. In step 2305, the basic fuel amount that has been subjected to the aforementioned post-startup increase correction coefficient is multiplied by the water temperature correction coefficient to perform correction.

  In step 2306, correction is further performed by multiplying the read fuel property correction coefficient. In step 2307, the final fuel injection quantity is output.

  FIG. 24 shows an example of a detailed flowchart of fuel correction by the fuel property correction coefficient in the embodiment shown in FIG.

  In step 2401, a post-startup increase correction coefficient is read. In step 2402, the correction is performed by multiplying the fuel property correction coefficient 1 by the post-startup increase correction coefficient.

  In step 2403, a water temperature correction coefficient is read. In step 2404, the fuel property correction coefficient 2 is multiplied by the water temperature correction coefficient to perform correction.

  In steps 2405 and 2406, the basic fuel amount is multiplied by the post-startup increase correction coefficient and the water temperature correction coefficient corrected by the fuel property correction coefficient, and in step 2407, the fuel injection quantity is output.

  FIG. 25 shows an example of a detailed flowchart for performing fuel property correction with respect to acceleration increase during engine acceleration according to the embodiment shown in FIG.

  In step 2501, the throttle opening is read. In step 2502, the engine speed is read. In step 2503, the engine water temperature is read.

  In step 2504, an acceleration increase coefficient is calculated based on the throttle opening, engine speed, and engine water temperature.

  In step 2505, the fuel property correction coefficient is read, and in step 2506, the fuel property correction is performed by multiplying the acceleration increase coefficient by the fuel property correction coefficient.

  In step 2507, the basic fuel amount is multiplied by the acceleration increase correction coefficient subjected to the fuel property correction, and in step 2508, the fuel injection amount is output to the fuel injection valve.

  FIG. 26 shows an example of a detailed flowchart for obtaining the acceleration increase amount.

  In step 2601, the throttle opening is read. In step 2602, a difference value for a predetermined time of the amount of change in throttle opening is calculated. In step 2603, the engine speed is read.

  In step 2604, the acceleration increase coefficient is searched from the difference value of the throttle opening change amount for a predetermined time and the engine speed. In step 2605, the engine water temperature is read, and in step 2606, an acceleration increasing water temperature correction coefficient is retrieved from the engine water temperature.

In step 2607, the acceleration increase correction coefficient is multiplied by the acceleration increase water temperature correction coefficient to perform water temperature correction. In step 2608, the final acceleration increase correction coefficient is output.

It is a block diagram showing one embodiment of a control device of an internal-combustion engine provided with a fuel property judging device by the present invention. It is a hardware block diagram which shows one Embodiment of the hardware configuration of the internal combustion engine which a fuel control apparatus provided with the fuel property determination apparatus by this invention controls. It is a block diagram which shows one Embodiment of the internal structure of the engine control apparatus provided with the fuel property determination apparatus by this invention. It is explanatory drawing which shows an example of the wall flow retention of the fuel in the intake passage of an internal combustion engine. It is a graph which shows an example of the setting characteristic of the increase correction coefficient after starting by this embodiment. It is a graph which shows an example of the setting characteristic of the water temperature correction coefficient by this embodiment. It is a graph which shows an example of the HC emission characteristic discharged | emitted at the time of engine starting. It is a graph which shows an example of the engine rotation behavior at the time of engine starting. It is a graph which shows an example of the relationship between the engine torque at the time of idling, and ignition timing. It is a block diagram which shows an example of the control logic of ISC ignition timing correction by this embodiment. It is a graph which shows an example of the behavior of idling rotation speed and ignition timing correction amount. It is a graph which shows an example of the power spectrum of the frequency analysis of ISC ignition timing correction amount. It is a block diagram which shows one Embodiment of the control logic of the fuel property determination means of this invention. It is a time chart which shows an example of the data acquisition timing for the frequency analysis in this embodiment. It is a block diagram which shows other embodiment of the control logic of the fuel property determination means of this invention. It is a block diagram which shows one Embodiment of the fuel correction at the time of the start by the fuel property correction coefficient by this invention. It is a block diagram which shows other embodiment of the fuel correction at the time of the start by the fuel property correction coefficient by this invention. It is a block diagram which shows one Embodiment of the fuel property correction | amendment with respect to the acceleration increase at the time of the engine acceleration by this invention. It is a block diagram which shows one Embodiment of the calculation process of the acceleration increase correction coefficient in this embodiment. It is a flowchart which shows the control procedure of the fuel control apparatus provided with the fuel property determination means by this invention. It is a flowchart of the fuel property determination means control procedure by one Embodiment. It is a flowchart of the fuel property determination means control procedure by other embodiment. It is a flowchart of one Embodiment of the fuel correction | amendment based on the fuel property correction coefficient which the fuel property determination means by this invention outputs. It is a flowchart of other embodiment of the fuel correction | amendment based on the fuel property correction coefficient which the fuel property determination means by this invention outputs. It is a flowchart which shows one Embodiment of the control procedure which performs fuel property correction | amendment with respect to the acceleration increase at the time of the engine acceleration by this invention. It is a flowchart of the control procedure which calculates | requires the acceleration increase in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Engine speed calculation means 102 Basic fuel calculation means 103 Basic fuel correction coefficient calculation means 104 Basic ignition timing calculation means 105 ISC means 106 Fuel property judgment means (device)
106-1 First fuel property determination means 106-2 Second fuel property determination means 107 Air-fuel ratio feedback control coefficient calculation means 108 Target air-fuel ratio setting means 109 Basic fuel correction means 110 Ignition timing correction means 111-114 1 to 4 cylinders Fuel injection means 115 to 118 1 cylinder to 4 cylinder ignition means 119 ISC valve control means 201 Internal combustion engine 202 Throttle throttle valve 203 Idle speed control valve (ISC valve)
204 Intake Pipe 205 Intake Pipe Pressure Sensor 206 Fuel Injection Valve 207 Crank Angle Sensor 208 Ignition Module 209 Water Temperature Sensor 210 Oxygen Concentration Sensor 211 Swirl Control Means 212 Ignition Key Switch 213 Spark Plug 214 Cylinder Block 215 Exhaust Pipe 216 Valve 217 Throttle Opening Sensor 250 Engine Control Unit 301 I / O Driver 302 Arithmetic Unit 303 Nonvolatile Memory 304 Volatile Memory 401 Intake Passage 1001 Processing Block 1002 Adder 1003 Processing Block 1301 AND Circuit 1302 Switch 1303 Frequency Analysis Unit 1304 Power Spectrum Detection Unit 1305 to 1308 Processing Block 1401 AND circuit 1402 Switch 1403-1405 Band pass filter 14 6 switch 1407 to 1410 processing block 1501, 1502 processing block 1504 multiplier 1601 processing block 1603 multiplier 1604 processing block 1606, 1607 multiplier 1701 processing block 1703, 1704 multiplier 1801 delay unit 1802 adder 1803, 1804 processing block 1805 multiplication vessel

Claims (7)

A fuel property determination device for an internal combustion engine, comprising: ignition timing control means for controlling the ignition timing of the internal combustion engine; and means for controlling the idling rotational speed of the internal combustion engine to a predetermined target rotational speed by ignition timing control by the ignition timing control means Because
A fuel property determination device for an internal combustion engine, comprising: means for determining a fuel property from a control amount for controlling the idling speed to a predetermined target speed by the ignition timing control means.   The means for controlling the idling speed by controlling the ignition timing sets the ignition timing to the advanced side when the target speed during idling is higher than the detected value of idling speed, and the target speed during idling is idling. 2. The fuel property determination apparatus for an internal combustion engine according to claim 1, wherein the ignition timing is set to a retard side when the detected value is lower than the detection value.   The means for determining the fuel property includes means for performing frequency analysis on a control amount for controlling the idling speed by ignition timing control, and means for determining the fuel property from the frequency analysis result. Item 3. A fuel property determination apparatus for an internal combustion engine according to Item 1 or 2.   The means for determining the fuel property includes at least one or more bandpass filters, means for filtering a control amount for controlling the idling speed by ignition timing control with the one or more bandpass filters, and the bandpass filter. The fuel property determination device for an internal combustion engine according to claim 1 or 2, further comprising: means for determining a fuel property based on a filtering value obtained by the method.   5. A fuel control device for an internal combustion engine, comprising means for performing fuel correction according to the fuel property determined by the fuel property determination device for an internal combustion engine according to claim 1.   Means for calculating a correction coefficient corresponding to the fuel property determined by the fuel property determination device for an internal combustion engine according to any one of claims 1 to 4, and means for performing fuel correction at start-up by the correction coefficient; And a fuel control device for an internal combustion engine.   Means for calculating a correction coefficient corresponding to the fuel property determined by the fuel property determination device for an internal combustion engine according to any one of claims 1 to 4, and means for performing fuel correction during acceleration by the correction coefficient; And a fuel control device for an internal combustion engine.

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