JP2004084570A - Complete explosion determining device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize off timing of a starting operation, and to build an inexpensive system. <P>SOLUTION: An equivalent value of engine torque is calculated from an engine revolution change detected by the signal of the crank angle sensor 2 and an inertia moment corrected by the accessory loads (4 to 6). It is then integrated. When the integrated value reaches a prescribed value or more, the engine is determined to be in a complete explosion state, and its control is switched from the starting control to the normal control. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a complete explosion determination device for an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in starting an internal combustion engine, fuel injection amount control, ignition timing control, and intake air control are performed as start-up control separately from normal control to improve startability. The start-time control is set so as to operate with an excessive torque in consideration of component variations in order to prevent engine stall. Prolonged start-time control causes deterioration of fuel efficiency and exhaust.
[0003]
The switching from the starting control to the normal control is performed by inputting a signal of a starter switch operated by a driver to an engine control unit and detecting an off timing.
Japanese Patent Application Laid-Open No. 2000-257540 discloses that starting operation is determined from a signal of a crank angle sensor, and that the starting operation is ended when the engine speed reaches a predetermined speed or more. ing.
[0004]
[Problems to be solved by the invention]
However, when detecting a complete explosion state (a state in which the engine can rotate independently) based on the starter switch signal and switching from start-up control to normal control, the driver himself / herself determines the complete explosion state. Therefore, the fuel consumption and the exhaust vary due to the variation of the switching timing, and particularly when the off-timing is delayed, the time of the start-up control becomes longer, resulting in deterioration of the fuel efficiency and the exhaust.
[0005]
In addition, since a starter switch signal is taken into the engine control unit, a harness attached to the starter switch and an input terminal of the control unit are provided, which leads to an increase in cost.
Further, it is desirable to determine the complete explosion state by estimating the torque state of the engine. In the method described in the above publication, based on only the engine speed, the estimation of the torque state is performed accurately. It was difficult to judge the complete explosion with high accuracy.
[0006]
In view of such a conventional problem, the present invention can accurately determine the complete explosion state (off timing of starter driving or switching timing from start-up control to normal control) without using a starter switch signal. The purpose is to.
[0007]
[Means for Solving the Problems]
Therefore, in the present invention, the value corresponding to the shaft torque of the engine is detected, the value corresponding to the shaft torque is integrated, and the complete explosion state is determined based on the integrated value.
[0008]
【The invention's effect】
According to the present invention, the complete explosion state is determined based on the value corresponding to the shaft torque of the engine. Therefore, without using a starter switch signal, it is possible to appropriately change the start timing of the starter drive from the off-time or the start-time control to the normal control. Switching timing can be obtained.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a complete explosion determination device for an internal combustion engine.
Signals from a crank angle sensor 2, a water temperature sensor 3, an air conditioner switch 4, a power steering switch 5, and a generator (alternator) switch 6 are input to an ECU (engine control unit) 8 that controls the engine (including various actuators) 1. Is done.
[0010]
The crank angle sensor 2 outputs a POS signal (unit crank angle signal) and a REF signal (reference crank angle signal), and these signals are input to the ECU 8. The ECU 8 performs cylinder discrimination, detection of a crank angle position, and calculation of an engine rotation speed (rotation speed) based on the POS signal and the REF signal.
The water temperature sensor 3 outputs a signal corresponding to the cooling water temperature of the engine 1, and this signal is input to the ECU 8. The ECU 8 detects the cooling water temperature Tw of the engine 1 based on this signal.
[0011]
Inputs of the auxiliary switches, that is, the air conditioner switch 4, the power steering switch 5, and the generator switch 6 each output ON and OFF signals, and these signals are input to the ECU 8.
The complete explosion determination of the internal combustion engine having these configurations will be described with reference to FIG. FIG. 2 is a flowchart showing the determination of the complete explosion state of the internal combustion engine, and this flow is executed every predetermined time (for example, every 10 ms).
[0012]
In step 1 (shown as S1 in the figure, the same applies hereinafter), it is determined whether the complete explosion determination flag STOFFREQ is 1, that is, whether the complete explosion has been determined.
If the complete explosion has not been determined (STOFFREQ = 0), the process proceeds to step 2.
When STOFFREQ is 1, that is, when the complete explosion has been determined, the process returns. This is because the engine 1 has a rotation speed at which the engine 1 can rotate independently without stalling, and the fuel injection amount control and the like are switched from the starting control to the normal control.
[0013]
In step 2, it is determined whether an initial REF signal has been input from the crank angle sensor 2. If there is no input of the first REF signal, the routine returns because the cylinder cannot be discriminated yet. On the other hand, when the first REF signal is input, the process proceeds to step 3 because the cylinder can be determined.
In step 3, the integrated value STTRQSUM of the shaft torque equivalent value STRRQ obtained by the shaft torque equivalent value calculation / integration flow (FIG. 3) is read. Here, the shaft torque equivalent value calculation / integration flow of FIG. 3 will be described.
[0014]
FIG. 3 is a flowchart for detecting the shaft torque equivalent value STTRQ and calculating the integrated value STTRQSUM. This flow is executed when a REF signal is input from the crank angle sensor 2.
In step 11, the elapsed times TTRQ1 and TTRQ2 of the predetermined crank angle period are read. This will be described with reference to FIG.
[0015]
FIG. 5 is a time chart of the complete explosion determination, in which TDC indicates the position of the compression top dead center. Then, the elapsed time (time during which a predetermined number of POS signals are input) TTRQ1 of the predetermined crank angle period before the compression top dead center (TDC), and the elapsed time TTRQ2 of the predetermined crank angle period after the compression top dead center (TDC) Are read at the time of input of the REF signal (see points A and B in FIG. 5).
[0016]
In step 12 of FIG. 3, an inertia moment correction coefficient KSTTRQ corresponding to an input of an auxiliary switch (the air conditioner switch 4, the power steering switch 5, the generator switch 6) is obtained from a table obtained in advance, and is read. Here, description will be made with reference to FIG.
As shown in FIG. 6A, the accessory switches, that is, the air conditioner switch 4, the power steering switch 5, and the generator switch 6, have respective inertia moment correction coefficients K1, K2, and K3. Then, as shown in FIG. 6B, for example, when the air conditioner switch 4, the power steering switch 5, and the generator switch 6 are sequentially turned on, the integrated values of the respective inertia moment correction coefficients K1, K2, K3 are shown. (1 + K1 + K2 + K3) is obtained as the inertia moment correction coefficient KSTTRQ.
[0017]
In step 13 of FIG. 3, a shaft torque equivalent value STRRQ of the engine 1 is determined. Here, the torque T is generally obtained by the equation (1).
T = Ip × ΔNE (1)
Here, Ip is a moment of inertia, and ΔNE is an increase in the number of revolutions, that is, an angular acceleration. Then, the rotational speed increment ΔNE (rpm) of the equation (1) is determined by the predetermined crank angles θ1 and θ2 (°) before and after the combustion, and the elapsed time of the predetermined crank angle period before and after the compression top dead center. When represented by TTRQ1 and TTRQ2 (sec), the following equation is derived.
[0018]
T = Ip × (θ2 / 360 / (TTRQ2 / 60) −θ1 / 360 / (TTRQ1 / 60)) (2)
Equation (2) determines the rotational speed NE before and after combustion, respectively, and obtains an increase ΔNE in the rotational speed from the difference between these values. Here, if the crank angle sections before and after combustion for measuring the section time are equal (θ = θ1 = θ2), the following equation is obtained.
[0019]
T = Ip × (θ / 6) × (TTRQ1-TTRQ2) / (TTRQ1 × TTRQ2) (3)
When the shaft torque equivalent value STRRQ is obtained based on the equation (3), the following equation is obtained.
STTRQ = Ip ′ × KSTRQ × (TTRQ1-TTRQ2) / (TTRQ1 × TTRQ2) (4)
Here, Ip 'is the basic moment of inertia, which is the moment of inertia when there is no auxiliary switch input. It should be noted that the moment of inertia correction coefficient KSTTRQ due to the auxiliary equipment load includes a constant (θ / 6) shown in equation (3). By using the correction coefficient KSTRQ, the shaft torque equivalent value STRRQ can be corrected and calculated based on the load of the auxiliary machine.
[0020]
In step 14, the integrated value STRQSUM of the shaft torque equivalent value STRRQ obtained in step 13 is calculated by the following equation.
STTRQSUM = STTRQSUMz + STRQ (5)
Here, the previous integrated value STTRQSUMz is the integrated value of the shaft torque equivalent value STRRQ up to the previous time, and the integrated value of the shaft torque equivalent value STRRQ obtained by integrating the shaft torque equivalent value STRRQ obtained in step 13 with this value. Find STTRQSUM.
[0021]
In step 15, it is determined whether or not the integrated value STTRQSUM is 0 or more. If the integrated value STTRQSUM is equal to or greater than 0, a return is made, the process proceeds to step 3 in FIG. 2, the integrated value STTRQSUM is read, and the process proceeds to step 4.
On the other hand, if the integrated value STTRQSUM is less than 0, the process proceeds to step 16, where the integrated value STTRQSUM is set to 0. This is because, when a misfire occurs during combustion, the shaft torque equivalent value STRRQ of the cylinder in which the misfire occurs is a negative value, but the integrated value STTRQSUM is less than 0 due to the presence of torque assist by the starter. Because it will not be. The integrated value STTRQSUM calculated in this way is read in step 2 of FIG.
[0022]
In step 4, the determination count value STTRQCNT obtained from the shaft torque determination count flowchart (FIG. 9) is read. Here, the determination count value calculation flow in FIG. 4 will be described.
The flowchart of FIG. 4 is executed every time the REF signal is input (see points A and B in FIG. 5), and it is determined whether or not the integrated value STTRQSUM has exceeded a predetermined value STTRSM.
[0023]
In step 21, it is determined whether or not the integrated value STRQSUM of the shaft torque equivalent value STRRQ read in step 3 is equal to or greater than a predetermined value STRRQSM.
If the integrated value STTRQSUM is equal to or greater than the predetermined value STTRQSM, the process proceeds to step 22, and the number of times of determination that the integrated value STTRQSUM is determined to be equal to or greater than the predetermined value STTRQSM is counted up from the previous value STTRQCNTz (see the following equation). .
[0024]
STTRQCNT = STTRQCNTz + 1 (6)
On the other hand, if the integrated value STTRQSUM is smaller than the predetermined value STTRSM, the process proceeds to step 23, where the determination count value STTRCNT is set to 0, and the process returns.
After the return is made in step 22 or step 23, the process proceeds to step 4 in FIG. 2, the determination count value STRRQCNT is read, and the process proceeds to step 5.
[0025]
In step S5, a predetermined number of determination times STTRQCT corresponding to the cooling water temperature Tw is read from the table. This will be described with reference to FIG.
FIG. 7 is a table showing the relationship between the cooling water temperature Tw and the counter predetermined value STTRQCT, and is obtained in advance by experiments or the like. As shown in the figure, when the cooling water temperature Tw is low, it indicates that the predetermined number of determination times STTRQCT must be high.
[0026]
In step 6 of FIG. 2, it is determined whether or not the determination count value STTRCNT is equal to or greater than a predetermined value STRRQCT. Thereby, it is determined whether or not the engine 1 is in a complete explosion state. This indicates that when the cooling water temperature Tw is extremely low, the explosion will not be completed unless the period during which the integrated value STTRQSUM of the shaft torque equivalent value STTRQ exceeds the predetermined value STTRSM becomes long.
[0027]
If the determination count value STTRQCNT is equal to or greater than the predetermined value STTRQCT, the process proceeds to step 7, and the complete explosion determination flag STOFFREQ is set to 1 (see point B in FIG. 5). And it is a return. As a result, the control of the engine 1 is switched from the start control to the normal control.
On the other hand, if the determination count value STTRCNT is smaller than the predetermined value STTRCT in step 6, the process returns. This means that the state in which the integrated value STRQSUM of the shaft torque equivalent value STRRQ is equal to or greater than the predetermined value STRRQSM does not reach the predetermined period, and indicates that the state is not in the complete explosion state. In this case, the starting control is continued.
[0028]
According to the present embodiment, the shaft torque equivalent value STTRQ of the engine 1 is detected (step 13), the shaft torque equivalent value STRRQ is integrated (step 14), and the complete explosion state of the engine 1 is determined based on the integrated value STTRQSUM. Is determined (steps 3 to 6). For this reason, an appropriate shaft torque equivalent value STTRQ can be obtained without using a starter switch signal, and an appropriate timing for turning off the starter drive and for switching from start-up control to normal control can be obtained.
[0029]
Further, according to the present embodiment, the shaft torque equivalent value detecting means calculates the shaft torque equivalent value STRRQ based on the change amount of the engine rotation speed (steps 11 to 13). Therefore, the shaft torque equivalent value STTRQ can be calculated based on the signal from the crank angle sensor 2 which is a general engine input signal, and a harness attached to the starter key switch, an input terminal of the ECU 8, a special sensor, and the like are required. And a cheap system can be constructed.
[0030]
Further, according to the present embodiment, the shaft torque equivalent value detecting means calculates the shaft torque equivalent value STRRQ based on the change amount of the engine rotation speed and the inertia moment, and corrects the inertia moment based on the accessory load. (Steps 11 to 13). For this reason, the shaft torque equivalent value STRRQ can be accurately calculated in consideration of the moment of inertia, and can be calculated more accurately by correcting the moment of inertia with the load of the auxiliary equipment, so that the complete explosion determination can be appropriately performed.
[0031]
Further, according to the present embodiment, the shaft torque equivalent value detecting means determines the amount of change in the engine rotational speed as the elapsed time TTRQ1 of the predetermined crank angle period before the compression top dead center and the predetermined crank angle period after the compression top dead center. (Steps 11 to 13). Therefore, the amount of change in the rotation speed of the engine 1 can be appropriately detected, and the complete explosion state can be appropriately determined.
[0032]
Further, according to the present embodiment, the shaft torque equivalent value STRRQ is detected for each cylinder (step 2) and integrated after the cylinder discrimination (step 14). For this reason, misfire occurs frequently and is unstable due to the smoldering or covering of the spark plug at the time of starting, but the shaft torque equivalent value STRRQ is detected for each cylinder, and after the cylinder discrimination, the shaft from the first explosion to the present time is detected. By determining the integrated value STTRQSUM of the torque equivalent value STTRQ, it is possible to improve the determination accuracy of the complete explosion state.
[0033]
Further, according to the present embodiment, the complete explosion determining means determines that the complete explosion has occurred when the state in which the integrated value STTRQSUM is equal to or greater than the predetermined value STTRSM continues for a predetermined period (determination count predetermined value STTRQCT) (step 6). For this reason, engine stall due to a decrease in engine speed can be prevented regardless of the presence or absence of a misfire, and a complete explosion state can be appropriately determined.
[0034]
Further, according to the present embodiment, the predetermined period in which the integrated value STTRQSUM is equal to or greater than the predetermined value STTRQSM (the predetermined number of determination times STTRQCT) is set according to the cooling water temperature Tw of the engine 1 (steps 5 and 6). . For this reason, the number of determinations STTRQCNT is determined based on the fact that the integrated value STTRQSUM of the shaft torque equivalent value STTRQ is equal to or greater than the predetermined value STTRQSM and is equal to or greater than the predetermined value STTRQCT in which combustion is continued. Thus, the complete explosion state can be properly determined.
[0035]
Further, according to the present embodiment, the lower limit value of the integrated value STTRQSUM is set to 0 (step 16). For this reason, if a misfire occurs during combustion, the shaft torque equivalent value STRRQ of the cylinder in which the misfire has occurred may be a negative value, but the torque assist by the starter is present, so that the lower limit value of the integrated value STTRQSUM is negative. And the erroneous determination of the complete explosion determination can be prevented.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a complete explosion determination device for an internal combustion engine. FIG. 2 is a flowchart showing determination of a complete explosion state of the internal combustion engine. FIG. 3 is a flowchart of detecting a shaft torque equivalent value and calculating an integrated value thereof. 4) Flow chart for calculating the number of times of judgment [FIG. 5] Time chart of complete explosion judgment [FIG. 6] Diagram showing inertia moment correction coefficient according to input of auxiliary switch [FIG. 7] Cooling water temperature and predetermined number of times of judgment [Description of reference numerals]
1 engine 2 crank angle sensor 3 water temperature sensor 4 air conditioner switch 5 power steering switch 6 generator switch 8 ECU

Claims (8)

Means for detecting a shaft torque equivalent value of the engine;
Means for integrating the shaft torque equivalent value;
Means for determining a complete explosion state of the engine based on the integrated value;
A complete explosion judging device for an internal combustion engine, comprising: The complete explosion judging device for an internal combustion engine according to claim 1, wherein the shaft torque equivalent value detection means calculates a shaft torque equivalent value based on a change amount of an engine rotation speed. The shaft torque equivalent value detecting means calculates a shaft torque equivalent value based on a change amount of an engine rotation speed and an inertia moment, and corrects the inertia moment based on an auxiliary machine load. A complete explosion determination device for an internal combustion engine according to claim 1. The shaft torque equivalent value detecting means obtains a change amount of the engine rotational speed based on an elapsed time of a predetermined crank angle period before the compression top dead center and an elapsed time of the predetermined crank angle period after the compression top dead center. The complete explosion judging device for an internal combustion engine according to claim 2 or 3, wherein: The complete explosion determination device for an internal combustion engine according to any one of claims 1 to 4, wherein the shaft torque equivalent value is detected for each cylinder, and integrated after cylinder identification. The complete explosion determining means determines that a complete explosion has occurred when a state in which the integrated value is equal to or greater than a predetermined value continues for a predetermined period or more. Complete explosion determination device for internal combustion engine. 7. The complete explosion judging device for an internal combustion engine according to claim 6, wherein the predetermined period is set according to an engine cooling water temperature. The apparatus according to any one of claims 1 to 7, wherein a lower limit value of the integrated value is set to 0.

Images