JP5241694B2 - Cylinder inflow air amount correction method at engine start, and fuel control device including the method - Google Patents

Description

  The present invention relates to an engine inflow air amount detection method for obtaining a flow rate of air flowing into a cylinder of an engine, a device for executing the method, and a fuel injection amount control device including the device.

  Speaking of conventional technology, the intake pipe pressure is estimated, and the estimated intake pipe pressure and the engine speed detected by the engine speed detecting means are used to calculate the inside of the cylinder per unit time or unit engine speed. 2. Description of the Related Art An inflow air amount detection device for an engine is known, which is provided with cylinder air amount estimation means for estimating an air mass flow rate flowing into the engine.

Japanese Patent No. 2908924

  However, the above-described conventional method is configured such that if the engine speed is not detected, the amount of air flowing into the cylinder cannot be estimated and calculated, and the intake pipe estimated pressure during cranking is not mentioned. For this reason, in systems where the throttle opening is relatively closed when the engine is started, or in systems where cylinder determination is slow so that the engine speed can be calculated, the actual intake pipe pressure decreases immediately after cranking starts. However, the intake pipe pressure estimated value remains at the initial value (atmospheric pressure) until the engine speed is detected, and the difference between the actual intake pipe pressure and the intake pipe pressure estimated value increases. As a result, the amount of air flowing into the cylinder during the increase in rotation after the first explosion is often calculated, and the air-fuel ratio at the time of the complete explosion becomes rich, which may deteriorate exhaust and drivability.

  When the starter SW is turned on when the engine is started, the engine speed at cranking is calculated. Until the engine speed calculated based on the crank angle sensor is calculated, the engine speed at cranking is used. The calculation of the intake pipe pressure is started by calculating the cylinder inflow air amount.

  Further, based on the amount of change in engine speed per unit time since the first explosion, the cylinder inflow air amount calculated when the engine speed increases is corrected.

  Since the present invention starts the estimation of the intake pipe pressure immediately after the start of cranking of the engine start, the deviation between the estimated intake pipe pressure at the start and the actual intake pipe pressure can be suppressed, and the rotation after the first explosion Since the cylinder inflow air amount during the ascent can be corrected, the deterioration of the air-fuel ratio at the time of complete explosion can be suppressed as a result.

An example of the control block of the fuel control apparatus of this invention. An example of the engine periphery which the fuel control apparatus of this invention controls. An example of the internal structure of the fuel control apparatus of this invention. An example of the physical model of the intake system of the engine of this invention. An example of the block which calculates | requires the cylinder inflow air amount of the fuel control apparatus of this invention. An example of the block which calculates | requires the engine speed for the cylinder inflow air amount calculation of the fuel control apparatus of this invention. An example of the block which calculates | requires the engine speed for the cylinder inflow air amount calculation of the fuel control apparatus of this invention. An example of the block which calculates | requires the correction | amendment ratio of the cylinder inflow air amount at the time of engine starting of the fuel control apparatus of this invention. An example of the chart which implement | achieved cylinder inflow air amount calculation of the fuel control apparatus of this invention. FIG. 9 is an example of a chart in consideration of the intake pipe pressure drop during cranking when the engine is started. An example of the flowchart of control of the fuel control apparatus of this invention. FIG. 6 is an example of a flowchart for obtaining a cylinder inflow air flow rate in FIG. 5. FIG. 7 is another example of a flowchart for obtaining the engine speed for calculating the cylinder inflow air amount in FIG. 6. FIG. 8 is another example of a flowchart for obtaining the engine speed for calculating the cylinder inflow air amount in FIG. 7. FIG. FIG. 9 is an example of a flowchart for obtaining a cylinder inflow air amount correction ratio when the engine is started in FIG. 8.

  A means for obtaining the amount of air taken in by the engine, a means for obtaining the engine speed at the time of starting the engine, a means for estimating the intake pipe pressure at the time of starting the engine, and the flow into the cylinder based on the engine speed and the intake pipe pressure And a means for obtaining a correction ratio for correcting the amount of air flowing into the cylinder when the engine is started.

  Hereinafter, main examples of the present invention will be described with reference to the drawings. FIG. 1 is an example of a control block of a fuel control device provided with an engine cylinder inflow air amount measuring method that is an object of the present invention. Block 101 is a block of the engine speed calculation means. By counting the number of inputs per unit time of the electrical signal of the crank angle sensor set at the predetermined crank angle position of the engine, mainly the pulse signal change, and calculating the number of revolutions per unit time of the engine calculate. A block 102 (intake air amount calculation means) includes a water temperature sensor output, a starter SW, a H / W sensor output, an intake air temperature sensor output, and a throttle sensor output. The engine speed at the time of cranking, the throttle air amount, and the intake pipe pressure This block calculates an estimated value and uses them to calculate the amount of air flowing into the cylinder of the engine. A block 103 calculates a basic fuel and an engine load index required by the engine in each region based on the engine speed calculated in the block 101 and the amount of air flowing into the cylinder of the engine. The block 104 calculates the correction coefficient in each operation region of the engine of the basic fuel calculated in the block 103 based on the engine speed calculated in the block 101 and the engine load described above. A block 105 is a block for determining an optimal ignition timing in each region of the engine by a map search or the like based on the engine speed and the engine load described above. A block 106 performs engine transient determination from the throttle opening described above, and calculates an acceleration / deceleration fuel correction amount associated with the transient. A block 107 sets a target rotational speed at idling in order to keep the engine idling rotational speed constant, and calculates a target flow rate to the ISC valve control means and an ISC ignition timing correction amount. A block 108 calculates an air-fuel ratio feedback control coefficient from the output of the oxygen concentration sensor set in the engine exhaust pipe so that the mixture of fuel and air supplied to the engine is maintained at a target air-fuel ratio described later. . In the embodiment, the oxygen concentration sensor described above outputs a signal proportional to the exhaust air / fuel ratio. However, the exhaust gas has a rich side / lean side 2 with respect to the stoichiometric air / fuel ratio. There is no problem even if it outputs two signals. A block 109 determines an optimum target air-fuel ratio in each region of the engine by a map search or the like based on the engine speed and the engine load. The target air-fuel ratio determined in this block is used for the air-fuel ratio feedback control in block 108 described above. In block 110, the basic fuel calculated in block 103 is corrected by the basic fuel correction coefficient in block 104, the acceleration / deceleration fuel correction amount in block 106, the air-fuel ratio feedback control coefficient in block 108, and the like. A block 111 corrects the ignition timing retrieved from the map in the block 104 with the acceleration / deceleration fuel correction amount in the block 106 described above. Blocks 112 to 115 are fuel injection means for supplying the engine with the fuel amount calculated in block 110 described above. Blocks 116 to 119 are ignition means for igniting the fuel mixture flowing into the cylinder in accordance with the required ignition timing of the engine corrected in block 111 described above. Block 120 is means for driving the ISC valve so as to achieve the target flow rate during idling calculated in block 107 described above.

  FIG. 2 shows an example of the engine periphery controlled by the control device for the internal combustion engine provided with the cylinder inflow air amount measuring method which is the subject of the present invention. The engine 200 controls the flow area of the flow path connected to the intake pipe 204 by bypassing the throttle throttle valve 202 and the H / W sensor 201 that measures the amount of air passing through the throttle portion of the engine. Thus, an idle speed control valve 203 for controlling the engine speed at idling, an intake pipe pressure sensor 205 for measuring the intake air temperature of the intake air amount in the intake pipe 204, and a fuel injection valve for supplying fuel required by the engine 206, a crank angle sensor 207 set at a predetermined crank angle position of the engine, an ignition plug for igniting a fuel mixture supplied into the cylinder of the engine, and an ignition energy based on an ignition signal from the engine control unit 212. Ignition module 208 for supplying engine cooling to the engine cylinder block A water temperature sensor 209 for detecting the temperature, an oxygen concentration sensor 210 for detecting the oxygen concentration in the exhaust gas set in the exhaust pipe of the engine, an ignition key switch 211 as a main switch for engine operation / stop, and a part of the exhaust gas. An EGR valve 213 returning to the intake pipe 204 and an engine control device 212 for controlling each auxiliary device of the engine are shown. The intake pipe pressure sensor 205 is integrated with an intake air temperature sensor that measures the temperature of the intake air.

  In the present embodiment, the oxygen concentration sensor 310 outputs a signal proportional to the exhaust air / fuel ratio. However, the exhaust gas has two signals on the rich side / lean side of the stoichiometric air / fuel ratio. It may be output. In this embodiment, as a fuel control parameter of the internal combustion engine, the amount of air passing through the throttle is detected by a thermal air flow meter to estimate the intake pipe pressure and calculate the cylinder inflow air amount. May be detected by a sensor.

  FIG. 3 is an example of an internal configuration of a fuel control device provided with a method for measuring the amount of air flowing into the cylinder of an engine that is the subject of the present invention. Inside the CPU 301 is set an I / O unit 302 that converts electrical signals of sensors installed in the engine into signals for digital arithmetic processing, and converts control signals for digital arithmetic into actual actuator drive signals. The I / O unit 302 is supplied with an intake air amount sensor 303, an intake air temperature sensor 304, a water temperature sensor 305, a crank angle sensor 306, a throttle opening sensor 307, an oxygen concentration sensor 308, and an ignition SW 309. . Output signals are sent to the fuel injection valves 311 to 314, the ignition coils 315 to 318, and the ISC opening command value 319 to the ISC valve via the output signal driver 310 from the CPU 301.

  FIG. 4 is an example of a physical model of the intake system of the engine that is the subject of the present invention. An H / W sensor 401 is set at the entrance of the intake system, and detects the amount of air QA00402 taken in by the engine. The cylinder inflow air amount QAR406 is determined by the intake pipe pressure PMMHG405, the engine speed, the engine exhaust amount, the intake air temperature, and the nonlinear intake efficiency determined by the engine region.

  FIG. 5 is an example of a block diagram outline for obtaining the cylinder inflow air amount of the fuel control device provided with the cylinder inflow air amount measuring method of the engine which is the subject of the present invention. The block 501 is a block for calculating the engine speed HNDATAS for measuring the cylinder inflow air amount, and details will be described later. A block 502 is a block for calculating the intake pipe pressure PMMHG. The current PMMHG is calculated using the air amount QA00 taken in by the engine, the previously calculated cylinder inflow air amount QARF, and the previously calculated PMMHG. A block 503 obtains an intake efficiency η that is a non-linear element from a map search based on the engine speed Ne and the intake pipe pressure PMMHG. η corrects a deviation from the theoretical value of the cylinder inflow air amount obtained based on the intake pipe pressure. A block 504 calculates the cylinder inflow air amount QARF from the intake efficiency η, the intake pipe pressure PMMHG, the intake air temperature THA, and the cylinder inflow air amount measurement engine speed HNDATAS. A block 505 is a block for calculating the start-time QAR correction factor DNEHOS. DNEHOS corrects the cylinder inflow air amount estimated when the engine speed is increased at the start based on the amount of change per unit time of the engine speed HNDATAS for calculating the cylinder inflow air amount. A block 506 is a block for calculating the cylinder inflow air amount QAR. The cylinder inflow air amount QARF is multiplied by the start time QAR correction factor DNEHOS to obtain the cylinder inflow air amount QAR. This cylinder inflow air amount QAR is used to calculate basic fuel and the like, and the above-mentioned cylinder inflow air amount QARF is used for intake pipe pressure estimation. If the intake air temperature sensor is not set in the engine, the error does not pose a problem even if the intake air temperature is fixed to a predetermined value (for example, 27 ° C.).

  Equation 1 represents a theoretical formula for obtaining the intake pipe pressure PMMHG and the cylinder inflow air amount QARF in FIG. Equation (1) shows a theoretical formula in the continuous region, and it is understood that the inflow / outflow of air into the intake pipe (between the throttle valve and the intake valve) in a minute time becomes a pressure gradient in the intake pipe. Show. Equation (2) is obtained by discretizing the equation (1) in Equation 1, and the intake pipe pressure PMMHG is obtained by executing this equation. Equation (3) represents an equation for obtaining the cylinder inflow air amount QARF from the intake pipe pressure obtained as described above. The basic equation is an ideal gas state equation, but the intake valve opening state and the exhaust valve Since it deviates from the theoretical value depending on the open state, the intake efficiency η and the intake efficiency correction coefficient VVTCRG are multiplied as nonlinear elements. Further, as described above, the intake air temperature may be fixed to a predetermined value.

  FIG. 6 is an example of a block diagram outline for obtaining the engine speed used for calculating the cylinder inflow air amount of the fuel control apparatus provided with the cylinder inflow air amount measuring method of the engine which is the subject of the present invention. In block 601, a table search is performed for the engine speed at the time of cranking based on the engine water temperature. The multiplier 602 multiplies the table search value by a correction coefficient to obtain the cranking rotation speed. The correction coefficient includes at least engine oil temperature correction, battery oil voltage correction, and engine oil temperature correction, and battery voltage correction, taking into account variations in engine differences and deterioration over time. The correction coefficient is calculated using a correction table or correction map according to the engine oil temperature and battery voltage. The engine oil temperature uses the output value if there is an oil temperature sensor, and the oil temperature if there is no oil temperature sensor. Use estimated or fixed values. When the starter SW is ON with the switch 603, the above-mentioned cranking rotation speed is selected, and when the starter SW is OFF, 0 is selected. In block 604, the engine rotation speed Ne calculated based on the crank angle sensor signal in block 101 described above and the cranking rotation speed, whichever is larger, are selected, and the cylinder inflow air amount calculation engine rotation is selected. Let HNDATAS be a few.

  The engine actually starts rotating during cranking, but the engine speed Ne is not calculated until the cylinder determination is completed. Therefore, in the case of the configuration as shown in FIG. 6, it is necessary to match the table and the correction coefficient so that the cranking speed is selected until the engine speed Ne is calculated.

  FIG. 7 differs from FIG. 6 in that the method of switching between the engine speed Ne calculated based on the crank angle sensor signal and the cranking speed is changed. The blocks 701 to 703 are the same as the blocks 601 to 603 described above. The switch 704 selects the engine speed Ne if the engine speed Ne calculated based on the crank angle sensor signal is greater than 0, and if the engine speed Ne is not greater than 0 (engine speed Ne = 0), the cranking rotation speed is selected as the engine rotation speed HNDATAS for cylinder inflow air amount calculation. In the present embodiment, the cranking speed is calculated by multiplying the table search value according to the engine water temperature by a correction coefficient including at least engine oil temperature correction and battery voltage correction. May be calculated by approximation by a theoretical formula or an experimental formula, or may be calculated as a fixed value.

  FIG. 8 is an example of a block diagram outline for obtaining a correction ratio for correcting the cylinder inflow air amount at the start of the engine of the fuel control device provided with the cylinder inflow air amount measuring method of the engine which is an object of the present invention. In block 801, HNDATAS calculated n times before in the past from the current value of the cylinder inflow air amount calculation engine speed HNDATAS is output. “N” of “past n times before” is determined according to the cylinder inflow air amount QARF, but “n” may be set to a fixed value, for example, two times in the past, regardless of the cylinder inflow air amount. The subtractor 802 subtracts HNDATAS calculated n times before in the past from the current value of the cylinder inflow air amount calculation engine speed HNDATAS to calculate the amount of change in engine speed per unit time. In block 803, a value obtained by applying a weighted average to the HNDATAS difference to obtain a value is set as a starting rotation speed increase rate. In block 804, a table search is performed for the cylinder inflow air amount QAR correction ratio at the start according to the rotation increase rate at the start. In the switch 805, when the correction cancellation condition for the cylinder inflow air amount correction at the time of starting is satisfied, the QAR correction ratio DNEHOS at the time of starting selects 1.0 to invalidate the correction, and when the correction cancellation condition is not satisfied, the table search value Select. In block 806, the correction cancellation condition is calculated. The conditions for canceling the correction are as follows: “The engine speed is greater than or equal to a predetermined value” after the ignition key is turned on, “The difference between the flow rate measured by the H / W sensor and the cylinder inflow air amount is less than or equal to a predetermined value”, The correction cancellation condition is satisfied when one of the above is experienced. The above experience is cleared when the ignition key is turned on again after the ignition is turned off, or when the starter switch is turned on.

  FIG. 9 is an example of a chart that realizes the calculation of the cylinder inflow air amount of the fuel control device provided with the cylinder inflow air amount measurement method for the engine that is the subject of the present invention. In a system in which the throttle opening at the time of engine start is relatively closed, or in a system in which the cylinder determination that enables calculation of the engine speed is slow, the actual intake pipe pressure starts to decrease from the start of cranking. The premise of this example is that the initial value of the estimated intake pipe pressure remains atmospheric until the cylinder determination is finished and the engine speed is calculated, taking into account the decrease in intake pipe pressure during cranking. There is nothing. Line 901 is the estimated intake pipe pressure, line 902 is the actual intake pipe pressure, line 904 is the engine speed, line 905 is the cylinder inflow air amount, line 906 is the original expected cylinder inflow air amount, line 908 is the air-fuel ratio, line Reference numeral 909 denotes an original expected value of the air-fuel ratio. In the case of this example, as described above, since the decrease in the actual intake pipe pressure at the time of cranking is not considered, the actual intake pipe pressure is decreased as shown in area 903, but the estimated intake pipe pressure is Since the initial value (atmospheric pressure) remains until the cylinder determination is completed and the engine speed is calculated, a difference between the actual pressure and the estimated pressure occurs. As a result, as shown in area 907, the cylinder inflow air amount is calculated with respect to the original expected cylinder inflow air amount, and as shown in area 909, the air / fuel ratio with respect to the original expected air / fuel ratio value is calculated. Becomes rich and affects exhaust and drivability.

  FIG. 10 is an example in consideration of a decrease in the actual intake pipe pressure during cranking with respect to FIG. 9 described above. Line 1001 is an estimated intake pipe pressure when a decrease in the actual intake pipe pressure during cranking is not considered, and line 1002 is an estimated intake pipe pressure when a decrease in the actual intake pipe pressure during cranking is considered, line 1003 Is the engine speed when the reduction of the actual intake pipe pressure during cranking is not considered, line 1004 is the engine speed when the reduction of the actual intake pipe pressure during cranking is considered, and line 1006 is during cranking The cylinder inflow air amount when the actual intake pipe pressure decrease is not taken into consideration, line 1007 is the cylinder inflow air amount when the actual intake pipe pressure decrease during cranking is taken into account, and line 1009 is the actual amount during cranking The air-fuel ratio when the reduction of the intake pipe pressure is not taken into consideration. It indicates the ratio.

  In the case of this example, considering the decrease in the actual intake pipe pressure at the time of cranking, when the starter SW is turned on, as shown in an area 1003, the engine speed at the time of cranking is calculated, and after the cylinder determination is completed. Until the engine speed is calculated, calculation of the cylinder inflow air flow rate and intake pipe pressure estimation are started using the cranking speed. Further, when the engine speed is increased after the engine is started, the air-fuel ratio immediately after the start can be adjusted by correcting the cylinder inflow air amount after the start in accordance with the rising gradient (the engine speed increase rate). In addition, after starting the cylinder, the cylinder inflow air amount correction is made after the ignition key is turned on, "the engine speed has become a predetermined value abnormality", "the difference between the H / W sensor measured flow rate and the cylinder inflow air amount is less than the predetermined value. ”Or“ Idle switch is turned from ON to OFF ”, the correction is canceled. As a result, as shown in area 1008, the cylinder inflow air amount is calculated to be lower than the cylinder inflow air amount when the decrease in the actual intake pipe pressure at the time of cranking is not taken into consideration, and as shown in area 1011. In addition, the richness of the air-fuel ratio when the reduction of the actual intake pipe pressure during cranking is not taken into consideration can be suppressed, and the exhaust and drivability can be improved.

  FIG. 11 is an example of a detailed flowchart of a fuel control device provided with a method for measuring the amount of air flowing into the cylinder of an engine that is the subject of the present invention. In step 1101, the electrical signal of the crank angle sensor is processed to calculate the engine speed. In step 1102, outputs of the H / W sensor, the intake air temperature sensor, the water temperature sensor, and the throttle sensor are read. In step 1103, it is determined whether or not the current calculation is the first calculation after turning on the ignition key. If it is determined that this is the first calculation, the estimated value of the intake pipe pressure is initialized at step 1104. Initialization is mainly atmospheric pressure, but if an atmospheric pressure sensor or the like is provided, the output value may be used. In step 1105, it is determined whether or not the engine is starting. In this embodiment, when the starter SW is turned ON, it is determined that the engine is started, and the process proceeds to the start-up process in step 1106. If not, the step 1106 is skipped and the process proceeds to step 1107. In the start-up process in step 1106, the engine rotational speed for cylinder inflow air measurement and the start-up cylinder inflow air amount correction ratio are calculated.

  In step 1107, the intake pipe pressure PMMHG is calculated. In step 1108, the cylinder inflow air amount QAR is calculated. In step 1109, the basic fuel amount and the engine load are calculated. In step 1110, the basic fuel correction coefficient is searched for a map. In step 1111, acceleration / deceleration determination is performed based on the throttle sensor output, and in step 1112, the fuel correction amount during acceleration / deceleration is calculated. In step 1113, the output of the oxygen concentration sensor is read. In step 1114, a target air-fuel ratio is set. In step 1115, an air-fuel ratio feedback control coefficient is calculated so that the target air-fuel ratio can be realized. In step 1116, the basic fuel correction coefficient, the air-fuel ratio feedback control coefficient, and the like are corrected to the basic fuel amount. In step 1117, the basic ignition timing is searched for a map. In step 1118, an acceleration / deceleration ignition timing correction amount is calculated, and in step 1119, the basic ignition timing is corrected. In step 1120, the target rotational speed of the ISC is set. In step 1121, the ISC target flow rate is calculated, and the ISC valve is controlled.

  FIG. 12 is an example of a flowchart corresponding to the block diagram for obtaining the cylinder inflow air amount QAR of FIG. In step 1201, the water temperature sensor output TWN, the engine speed Ne calculated based on the crank angle sensor, the H / W sensor output QA00, and the intake air temperature sensor output THA are read. In step 1202, an engine speed HNDATAS for calculating the cylinder inflow air amount is calculated. In step 1203, the current PMMHG is calculated from the THA, QA00, the previously calculated cylinder inflow air amount QARF, and the previously calculated PMMHG. In step 1204, the intake efficiency η is retrieved from the engine speed Ne and the PMMHG. In step 1205, the cylinder inflow air amount QARF is calculated from the engine speeds HNDATAS, THA, the PMMHG, and the η. In step 1206, the start-time QAR correction ratio DNEHOS is calculated in accordance with the rate of increase in HNDATAS. In step 1207, the QARF is multiplied by the DNEHOS to calculate a cylinder inflow air amount QAR.

  FIG. 13 is an example of a flowchart corresponding to the block diagram for obtaining the cylinder inflow air calculation engine speed HNDATAS of FIG. 6 described above. In step 1301, the engine speed Ne, the water temperature sensor output TWN, and the starter SW calculated based on the crank angle sensor are read. In step 1302, a table search is performed for the cranking rotation speed base value using TWN. In step 1303, the cranking speed base value is multiplied by a correction coefficient including engine oil temperature correction and battery voltage correction. In step 1304, it is determined whether or not the engine is starting. In this embodiment, the starter SW is turned on and it is determined that the engine is started. If it is a start time, the process proceeds to step 1305; otherwise, the process proceeds to step 1306. In step 1305, the cranking rotation speed is selected by multiplying the table search value by the correction coefficient. In step 1306, 0 is selected as the cranking rotation speed. In step 1307, the greater of Ne and the cranking speed is set as the cylinder inflow air amount calculation engine speed HNDATAS.

  FIG. 14 is an example of a flowchart corresponding to the block diagram for obtaining the cylinder inflow air calculation engine speed HNDATAS of FIG. 7 described above. In step 1401, the engine speed Ne, the water temperature sensor output TWN, and the starter SW calculated based on the crank angle sensor are read. In step 1402, a table search is performed for the cranking rotation speed base value using TWN. In step 1403, the cranking speed base value is multiplied by a correction coefficient including engine oil temperature correction and battery voltage correction. In step 1404, it is determined whether or not the engine is starting. In this embodiment, the starter SW is turned on and it is determined that the engine is started. If it is a start time, the process proceeds to step 1405. If it is not a start time, the process proceeds to step 1406. In step 1405, the cranking rotation speed is selected by multiplying the table search value by the correction coefficient. In step 1406, 0 is selected as the cranking rotation speed. In step 1407, it is determined whether Ne is greater than 0 (Ne> 0?). If Ne> 0, the process proceeds to step 1408, and if Ne> 0, the process proceeds to step 1409. In step 1408, Ne is set as the engine rotation speed HNDATAS for calculating the cylinder inflow air amount. In step 1409, the cranking rotation speed is set to the cylinder rotation air amount calculation engine rotation speed HNDATAS.

  FIG. 15 is an example of a flowchart corresponding to the block diagram for obtaining the start-time QAR correction ratio DNEHOS shown in FIG. In step 1501, the QARF, QA00, starter SW, idle SW, and HNDATAS are read. In step 1502, a start-time QAR correction cancellation condition is calculated. In step 1503, the amount of change per unit time of the engine speed is calculated from HNDATAS and QARF. In step 1504, a weighted average is applied to the amount of change in the engine speed per unit time to calculate the starting rotational speed increase rate. In step 1505, the table is searched for the start-time QAR correction ratio based on the start-up rotation rate. In step 1506, it is determined whether the start-time QAR correction cancellation condition is satisfied. When the correction cancellation condition is satisfied, the process proceeds to step 1507. When the correction cancellation condition is not satisfied, the process proceeds to step 1508. In step 1507, the starting QAR correction ratio DNEHOS is selected to be 1.0. In step 1508, the DNEHOS is selected as the table search value.

  As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. Moreover, each component is not limited to the said structure, unless the characteristic function of this invention is impaired.

201, 401 H / W sensors 202, 403 Throttle throttle valve 205 Intake pipe pressure sensor 206 Fuel injection valve 207 Crank angle sensor 210 Oxygen concentration sensor 212 Engine control device 402 Intake air amount 405 Intake pipe pressure 406 Cylinder inflow air amount 501 Cylinder inflow Engine speed calculation block 505 for calculating the air amount Correction rate calculation block 805 for cylinder inflow air amount at start-up Correction cancellation condition determination block for cylinder inflow air amount correction at start-up

Claims (5)

Means for obtaining the amount of air taken in by the engine;
Means for obtaining the engine speed at engine startup based on at least one of engine water temperature, engine oil temperature, and battery voltage;
Means for estimating the intake pipe pressure at the start of the engine;
Means for obtaining a flow rate of air flowing into the cylinder based on the engine speed and the intake pipe pressure;
Means for obtaining a correction ratio for correcting the amount of air flowing into the cylinder when starting the engine;
And means for obtaining the engine speed during the engine start by selecting the larger value of the engine speed obtained based on the signal of the engine speed and the crank angle sensor at the engine starting,
The engine fuel control device is characterized in that cranking is being performed by a starter when the engine is started. The means for switching between the engine speed at the time of cranking and the engine speed obtained based on the signal of the crank angle sensor,
Initially, the engine speed at the time of cranking is used, and when the value of the engine speed obtained based on the signal of the crank angle sensor becomes larger than 0, the engine speed obtained based on the signal of the crank angle sensor 2. The fuel control apparatus for an engine according to claim 1, wherein switching is performed.   2. The engine fuel control apparatus according to claim 1, wherein the intake pipe pressure at the time of starting is estimated from a cylinder inflow air amount calculated using an engine speed at the time of cranking. The means for obtaining a correction ratio for correcting the amount of air flowing into the cylinder at the time of starting the engine obtains a correction ratio according to the amount of change per unit time in engine speed from the first explosion. Engineon fuel control device. The unit time for calculating the change amount of the engine speed selected as the larger value of the engine speed obtained at the start of the engine and the engine speed obtained based on the signal of the crank angle sensor flows into the cylinder. 2. The engine fuel control apparatus according to claim 1, wherein the time is determined by the amount of air to be generated.

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