JP4244484B2 - Engine ignition timing control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine ignition timing control device, and more particularly to an apparatus having a function of detecting an ignition output state.
[0002]
[Prior art]
The engine ignition timing control device is composed of an ECU (electronic control unit). The ECU detects the state of the engine based on signals from each sensor, and determines the optimum ignition timing according to the engine state at that time. Send a signal to the igniter. Crank synchronization processing of ignition output is performed by generating a pulse when the offset time has elapsed from the crank edge (crank signal pulse edge). At this time, the ignition energization signal is generated using several timers. The output is distributed to multiple cylinders of the number of timers or more. In recent years, with the advancement of microcomputer functions, a technique has been used in which independent ignition control is performed independently of other cylinders by using a timer dedicated to each cylinder.
[0003]
[Problems to be solved by the invention]
Since the above-described technique can perform independent ignition control for each cylinder, it is possible to overlap the energization periods of a plurality of cylinders (overlap). When the angle between the cylinders is wide like a four-cylinder engine, it is unlikely that the energization periods overlap, but when the number of cylinders increases, the energization periods may overlap. Also, when the battery voltage drops, the energization period is lengthened to ensure ignition energy to prevent misfires.At high speeds, the ignition interval is shortened in time, so the energization period overlaps with longer energization. It is assumed that
[0004]
On the other hand, for example, the ignition confirmation signal IGF may be used for igniter failure detection. In this case, the ignition confirmation signal IGF takes the ignition output signal of each cylinder by the igniter and returns an OR (OR) signal to the ECU. At this time, when the energization periods of the cylinders overlap as described above, It is conceivable that the IGF signal is lost and erroneously determined as a failure.
[0005]
The present invention has been made under such a background, and its object is to reliably perform ignition confirmation in a system that outputs an ignition energization signal independently for each cylinder and receives an ignition confirmation signal on a common line. It is an object of the present invention to provide an engine ignition timing control device.
[0006]
[Means for Solving the Problems]
It is necessary to determine whether or not the energization periods of the cylinders overlap each other in order to prevent erroneous determination due to the loss of the IGF signal when the energization periods of the cylinders overlap. However, even if the actual ignition output does not overlap in the port output state, it is considered that they overlap due to the response delay of the ignition output circuit of the ignition timing control device (ECU, etc.) and the igniter circuit. Therefore, it is necessary to determine the overlap of the ignition output.
[0007]
In view of this, the invention described in claim 1 is characterized by prohibiting the determination of abnormality of the ignition output based on the ignition confirmation signal when successive ignition energization signals overlap or when they are close to each other within a predetermined period width. Yes. In other words, with respect to an ignition output system capable of overlapping ignition energization, it is not determined only by the output state of each cylinder, but considering that the actual energization overlaps, taking into account the response delay of the ignition output circuit and igniter circuit judge. Thereby, even when the calculated value of ignition energization and the port output state are not overlapped, it is possible to reliably determine when the actual energization is overlapping.
[0008]
Thus, in the system that outputs the ignition energization signal independently for each cylinder and receives the ignition confirmation signal on the common line, the ignition confirmation can be reliably performed.
[0009]
As in the second aspect of the invention, the dead zone indicating that the ignition energization signals that follow each other are close to each other within a predetermined period width includes at least a response delay of the input / output circuit and the internal circuit of the igniter. Practically preferred.
[0010]
As in the third aspect of the invention, it is determined whether successive ignition energization signals overlap or are close within a predetermined period of time by determining the energization start timing in a predetermined cylinder and the ignition target cylinder before that It is practically preferable to perform the operation based on the difference in ignition timing.
[0011]
As in the fourth aspect of the invention, in the third aspect of the invention, the determination timing that the successive ignition energization signals overlap or are close within a predetermined period width is determined by the previous ignition target cylinder. It is practically preferable that the timing of the ignition is always finished.
[0012]
According to the fifth aspect of the present invention, the pulse interval is measured by the pulse interval measuring unit with respect to the crank signal of the pulse train at every predetermined angular interval corresponding to the rotation of the crankshaft of the engine, and the multiplication signal generating unit generates the pulse Based on the current pulse interval by the interval measuring means, a multiplication signal having an integer multiple frequency is generated by the next pulse. Further, the ignition angle counter performs a counting operation based on the multiplied signal, and the ignition energization signal output means outputs the ignition energization signal according to the comparison result between the count value of the ignition angle counter and the energization start angle position and the energization cutoff angle position. Is output. As described above, by generating a multiplied signal at a predetermined angular interval to synchronize with the engine rotation, it is possible to eliminate the calculation for the conversion from angle to time and to reduce the processing load. In addition, since the ignition energization signal (energization start timing and ignition timing) can be set according to the angle, highly accurate ignition control and more reliable ignition confirmation can be performed with almost no influence from the acceleration / deceleration of the vehicle.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
The present embodiment is embodied in an ignition timing control device for a multi-cylinder gasoline engine for automobiles. FIG. 1 shows the configuration of an ignition timing control ECU 1 and an igniter 2 in the present embodiment. The engine is a 5-cylinder 4-cycle engine.
[0014]
The ignition timing control ECU 1 includes a microcomputer (hereinafter referred to as a microcomputer) 10 and an output circuit (in FIG. 1, only the output circuits 20 and 30 for the first and second cylinders are shown, and the output circuits for the third, fourth and fifth cylinders are omitted). An input IC 70 and an input filter circuit 80. On the other hand, the igniter 2 includes a drive circuit and a transistor for each cylinder. Here, in FIG. 1, only the driving circuit 201 and transistor Tr10 for the first cylinder, the driving circuit 202 and transistor Tr11 for the second cylinder are shown, and the driving circuit and transistors for the third, fourth, and fifth cylinders are omitted. did.
[0015]
In the ignition timing control ECU 1, the microcomputer 10 includes a CPU 11, a ROM 12, a RAM 13, and a timer module 14, and these members exchange data with each other via a data bus. The microcomputer 10 inputs signals from sensors, switches, and the like, and outputs an ignition energization signal IGT that is a drive signal to the igniter 2 (ignition device). Further, the CPU 11 of the microcomputer 10 takes in a signal (data) from a sensor / switch, etc., performs various calculations based on this data, and outputs an ignition energization signal IGT to perform ignition. In other words, ignition energization signals IGT1, IGT2,... For each cylinder are output from the ports P1, P2,..., Sent to the igniter 2 through the output circuits 20, 30, and the transistors Tr10, Tr11,. Ignition is performed by energizing.
[0016]
Here, the signals taken in by the ECU 1 include a crank signal from the crank sensor and a cam signal from the cam sensor. FIG. 2 shows a crank signal and a cam signal for one engine cycle (720 ° CA).
[0017]
The crank signal is composed of a pulse train at predetermined angular intervals corresponding to the rotation of the crankshaft of the engine, and has a missing tooth portion (reference position portion) in which a pulse is extracted in the middle of the pulse train. The crank signal in the present embodiment has a missing tooth configuration in which two pulses are missed every 60 pulses (60-2 tooth structure). In other words, the pulse interval of the pulse train is 6 ° CA, and there is a missing tooth portion with a pulse removed in the middle of this pulse train every 360 ° CA, and one of them (missing tooth for each 720 ° CA) is a front missing tooth. And the other (the other missing teeth for every 720 ° CA) is the back missing tooth. The cam signal is synchronized with the rotation of the camshaft of the engine, and is a cylinder discrimination signal for specifying the cylinder position. The falling edge is at an interval of 144 ° CA. This cam signal has a different cam signal phase level at the missing tooth position (front missing tooth and back missing tooth) of the crank signal that comes twice between 720 ° CA, and the cam signal level at the missing tooth position is high / The front and back of the missing tooth can be determined with wax.
[0018]
The reference position of the crank signal was a missing tooth part in which a pulse was extracted in the middle of the pulse train. However, the present invention is not limited to this, and other structures (structures such as inserting a pulse in the middle of the pulse train) are used. A reference position portion with unequal pulse intervals may be formed in the middle of the pulse train for each predetermined angular interval.
[0019]
The crank signal is input to the hard crank 100 of the timer module 14 of FIG. The cam signal is taken into the microcomputer 10.
On the other hand, the hard crank 100 provided in the timer module 14 of FIG. 1 is a functional unit that processes a crank signal in a hardware manner. With the hard crank 100, the processing of the crank signal shown in FIG. 2 (generation of an angle signal obtained by dividing the time between crank edges) can be performed in hardware.
[0020]
FIG. 3 shows the configuration of the hard crank 100.
In FIG. 3, a prescaler 101, a frequency dividing circuit 102, an edge time measurement counter 103, a multiplication register (edge time storage register) 104, a multiplication counter 105, an event counter 106, a guard counter 107, a reference counter 108, a follow-up counter (angle counter). ) 109 and an ignition angle counter 110. A signal Pφ from the prescaler 101 is sent to the edge time measurement counter 103 via the frequency divider circuit 102. Further, the signal Pφ is sent to a follow-up counter (angle counter) 109. Further, the crank signal is sent to the edge time measurement counter 103, the event counter 106, and the guard counter 107.
[0021]
FIG. 4 shows a time chart for generating an angle clock (angle signal). FIG. 4 shows an input crank signal, a count value of the edge time measurement counter 103, a stored value of the multiplication register 104, a count value of the multiplication counter 105, an output signal (multiplication clock) of the multiplication counter 105, and a value of the guard counter 107. N times the value, the count value of the reference counter 108, the count value of the follow-up counter 109, and the count value of the ignition angle counter 110.
[0022]
The edge time measurement counter 103 in FIG. 3 inputs a crank signal and measures the time (pulse interval) between the crank edges. Specifically, the edge time measurement counter 103 is a counter that counts up in time synchronization as shown in FIG. 4 and measures the time between crank edges (between falling edges of the crank signal). The measured value is multiplied by 1 / n and transferred to the multiplication register 104. The transferred data becomes the initial value of the multiplication counter 105 which is a down counter. An example of the multiplication value (n value) is “32”.
[0023]
The multiplication counter 105 in FIG. 3 uses the time between the crank edges measured by the edge time measurement counter 103 to generate a multiplication clock with 1 / n of the crank edge time. Specifically, the multiplication counter 105 counts down in a time-synchronized manner as shown in FIG. 4 and repeats the operation of generating a multiplied clock when underflowing and returning the count value to the initial value. When the next crank edge (falling edge of the crank signal) is input, the value of the multiplication register 104 and the initial value of the multiplication counter 105 are updated to the latest value. In this way, the multiplication counter 105 generates a multiplication signal (multiplication clock) having an integer multiple frequency by the next pulse based on the current pulse interval by the edge time measurement counter 103.
[0024]
As shown in FIG. 4, the reference counter 108 in FIG. 3 performs a count-up operation with a multiplied clock. The follow-up counter 109 in FIG. 3 counts up with a time synchronization clock (counts with an internal clock). The guard counter 107 is a counter that counts up every time the falling edge of the crank signal is input, and transfers a value that is n times (multiplied) the value before counting up to the reference counter 108 when the crank edge is input.
[0025]
Here, as shown in FIG. 4, the count value of the reference counter 108 cannot exceed the value (n times the count value) transferred from the guard counter 107 when the crank edge is input. The follow-up counter 109 counts up only when it is smaller than the count value of the reference counter 108. An angle clock (angle signal) is generated in synchronization with the count-up of the follow-up counter 109. In this way, an angle clock is generated by the three counters 107, 108, and 109.
[0026]
In this embodiment, the internal clock (signal Pφ from the prescaler) is 20 MHz, and the follow-up counter 109 can operate at a higher speed than other counters. In FIG. 4, at the time of deceleration, the count operation of the reference counter 108 and the follow-up counter 109 is such that the value of the reference counter 108 reaches n times the value of the guard counter 107 before the crank edge is input. 109 count-up is prohibited. In this way, the count-up operation of the reference counter 108 and the follow-up counter 109 is stopped at the multiplied value by the guard counter 107. As a result, at the time of deceleration, the counting operation of the follow-up counter 109 is stopped to prevent the generation of an angle clock exceeding a certain value.
[0027]
The angle clock generated in this way is sent to the ignition angle counter 110 of FIG. 3, and the counter 110 counts up with the angle clock (see FIG. 4). Therefore, the counter 110 functions as an angle timer. Based on the count value of the counter 110 as an angle timer, ignition control is performed in synchronization with the crank angle using a compare register. That is, the ignition control can be performed by the ignition angle counter 110 with the crank angle synchronized. In this way, a system that synchronizes with engine rotation by generating a multiplied signal (multiplied clock) at a predetermined angular interval eliminates the need for computation for conversion from angle to time and reduces processing load. In addition, accuracy can be improved (LSB = 0.1875 ° CA if n = 32).
[0028]
In FIG. 2, the front missing tooth side of the crank signal is the system initialization location. This system initialization position is the position of BTDC 6 ° CA of the fourth cylinder. When the count value of the follow-up counter 109 reaches the one-cycle guard value at this position, the counter 109 is initialized. Along with the initialization, a reset signal is sent to the ignition angle counter 110, and the ignition angle counter 110 is initialized and synchronized with the reset signal.
[0029]
The event counter 106 in FIG. 3 counts up at the falling edge of the pulse of the crank signal and outputs an angular period interrupt signal every time six of the same edges are input (every 36 ° CA). The CPU 11 detects the missing tooth position of the crank signal from the count value (number of edge inputs) of the event counter 106. The count value of the event counter 106 is initialized in one engine cycle (720 ° CA).
[0030]
FIG. 5 shows a time chart for controlling the ignition output by the ignition angle counter 110. The ignition output is controlled by the microcomputer 10 including the CPU 11.
[0031]
First, the energization start timing, ignition timing, and energization guard value are set by a predetermined 36 ° CA cycle interruption indicated by t1 in FIG. More specifically, the absolute angular position between the energization start timing calculated by the CPU 11 and the ignition timing 720 ° CA is set at a predetermined angle before the timing at which ignition output is to be performed (by interruption at a 36 ° CA cycle). In the register and the ignition timing setting register, an energization guard value is set as an initial value of the down counter. When the value of the angle timer (angle counter 110) matches the value of the energization start timing setting register (timing t2 in FIG. 5), the down counter starts and the ignition output port (P1, P2, etc. in FIG. 1) turns on. Then energization is started.
[0032]
Thereafter, when the angle timer (angle counter 110) coincides with the value of the ignition timing setting register at the timing of t3 in FIG. 5, the down counter is reset to “0” and the ignition output port is turned off to ignite. When the ignition timing is set to be greater than the energization guard value, the ignition output is turned off when the down counter becomes “0”.
[0033]
Thus, the CPU 11 sets the energization start angle position and the energization cutoff angle position of the ignition energization signal, and the microcomputer 10 compares the count value of the ignition angle counter 110 with the energization start angle position and the energization cutoff angle position. The ignition energization signal is output according to the comparison result.
[0034]
1 includes a transistor Tr1, resistors R1, R2, R3, and R4 and a capacitor C1. The input filter circuit 80 includes resistors R5 and R6 and capacitors C2 and C3.
[0035]
In the igniter 2 of FIG. 1, the transistor Tr10 is connected to the first cylinder ignition energization signal line from the ECU 1 via the drive circuit 201, and the collector terminal of the transistor Tr10 is connected to the first cylinder ignition via the port P11. The coil is connected. Similarly, a transistor Tr11 is connected to the second cylinder ignition energization signal line via the drive circuit 202, and a second cylinder ignition coil is connected to the collector terminal of the transistor Tr11 via the port P12. The ignition coil is energized when the transistors Tr10 and Tr11 are turned on by the ignition energization signal from the ECU 1, and ignition is performed.
[0036]
The transistors Tr10 and Tr11 are grounded via the current detection resistor R10, and a voltage corresponding to the current flowing through the transistors Tr10 and Tr11 is generated between both terminals of the resistor R10. The ignition monitor circuit 210 provided in the igniter 2 inputs a voltage generated between the terminals of the resistor R10 and sends an ignition confirmation signal IGF to the ECU 1. More specifically, as shown in FIG. 6, the ignition monitor circuit 210 in FIG. 1 turns on the ignition energization signal IGT and starts energization. When the current reaches 2 amperes in the igniter 2, the ignition monitor signal IGF is raised. At the same time, the ignition energization signal IGT is turned off and the energization is completed, and at the same time, the ignition confirmation signal IGF is turned off. As shown in FIG. 7, the CPU 11 latches the ignition confirmation signal IGF returned from the igniter 2 at a predetermined angular position (timing t10,..., T15 in FIG. 7) of each cylinder and operates the monitor flag. After that, the fail determination flag is operated from the monitor flag at a timing (ATDC 66 ° CA) at which ignition in each cylinder always ends. That is, when the energization operation for ignition is not executed, there is no ignition confirmation signal IGF (the level does not fall), and the monitor flag does not fall, so the fail determination flag is turned on. In this way, abnormality determination of the ignition output is performed. If the ignition confirmation signal is not input to the ECU 1 and is not ignited several times in succession, the fuel injection is stopped to prevent an abnormal increase in the catalyst temperature.
[0037]
Although FIG. 6 shows a system in which the ignition confirmation signal IGF is turned off when the ignition energization signal IGT is turned off, the present invention is also applicable to a system in which the ignition confirmation signal IGF is turned off when the current reaches 4 amperes. May be. Further, FIG. 7 shows a system in which the presence / absence of the ignition confirmation signal IGF for the previous cylinder is confirmed at the angular position. However, the present invention may be applied to the case where the next cylinder is energized.
[0038]
On the other hand, the ignition confirmation signal IGF from the ignition monitor circuit 210 of the igniter 2 in FIG. 1 is sent to the input port P100 of the microcomputer 10 through the input filter circuit 80 and the input IC 70 of the ECU 1 through one line L1. Thus, the ECU 1 outputs the ignition energization signal IGT to the igniter 2 independently for each cylinder, and the igniter 2 receives the ignition confirmation signal IGF corresponding to the ignition energization signal IGT on the common line L1.
[0039]
Next, the operation of the engine ignition timing control apparatus configured as described above will be described.
FIG. 7 shows a case where the energization of the ignition output does not overlap, but FIG. 8 shows a case where the energization of the ignition output overlaps. In FIG. 8, the ignition energization signal IGT1 in the first cylinder starts energization while the ignition energization signal IGT3 in the third cylinder is still energized, and the period of T10 overlaps. When the ignition energization periods of a plurality of cylinders overlap as shown in FIG. 8, the ignition confirmation signal (SG1) indicated by the broken line in the figure is lost, and as a result, the monitor flag (SG1 ′) does not appear. That is, since the ignition confirmation signal IGF simply captures the signal of each cylinder with OR, it cannot be latched by the monitor flag, and there is no monitor flag (SG1 ′) at the determination timing t13 in the third cylinder. Turns on. That is, a failure is determined from the ignition confirmation signal IGF, and erroneous detection is performed in a system having a diagnosis function.
[0040]
Thus, when ignition energization overlaps, a failure is erroneously detected from the ignition confirmation signal IGF. Therefore, in order to prevent this erroneous detection, abnormality detection is prohibited when ignition energization overlaps.
[0041]
Therefore, it is necessary to determine that the actual ignition operation overlaps. When determining the overlap of the ignition operation, if the calculation results of the respective cylinders are overlapped, it is naturally determined that there is an overlap, but the state at the output port of the microcomputer 10 (P1, P2, etc. in FIG. 1) and the actual ignition The operation differs depending on hardware factors such as the influence of the output circuits 20 and 30 of the ECU 1 and the circuits 201 and 202 inside the igniter. For this reason, even when there is no overlap in calculation, the determination is made by providing a dead zone in consideration of these delays.
[0042]
This will be described in detail below.
FIG. 9 is a timing chart showing the ignition output delay. In FIG. 9, the ignition energization signal IGT1 in the first cylinder, the potential at its connector (ECU output port), the ignition energization signal IGT2 in the second cylinder, the potential at its connector, the ignition confirmation signal IGF, and the CPU 11 are captured. Indicates voltage. That is, in FIG. 1, the ignition energization signal IGT is output from the ports (P1, P2, etc.) of the microcomputer 10, and the output circuits 20, 30 → connector → igniter 2 drive circuits 201, 202 → transistors Tr10, Tr11 → ignition monitor circuit 210. → Input filter circuit 80 → Input IC 70 → Microcomputer port P100 → Signal delay when taken into the CPU 11 is shown. In FIG. 9, an input signal is compared with a threshold value by an input IC 70 and is sent as a pulse wave to the microcomputer port P100.
[0043]
T1 in FIG. 9 is a delay time from when the ignition energization signal IGT1 in the first cylinder is turned off by the CPU 11 to when the ignition confirmation signal IGF taken in by the CPU 11 rises. T2 is the time from when the ignition energization signal IGT2 in the second cylinder is turned on by the CPU 11 to when the ignition confirmation signal IGF taken in by the CPU 11 is turned on.
[0044]
Here, if the maximum delay time from when the ignition energization signal IGT1 in the first cylinder is turned off until the ignition energization signal IGT2 in the second cylinder is turned on is Td, the maximum value of Td is T1-T2. T2 is set to “0” in consideration of the worst case. Therefore, the maximum value of T1 is the maximum delay time. The maximum value of T1 is the delay time of the ignition energization signal IGT in the output circuits 20 and 30, the delay time in the internal circuits 201 and 202 of the igniter 2, the filter time of the input filter circuit 80 of the ignition confirmation signal IGF, It is determined by the through input delay time in the input IC 70 and the IGF signal capture time in the microcomputer 10. For this reason, the maximum time of T1 from the turning off of the front cylinder is set as a dead zone for the ignition overlap determination.
[0045]
10, 11 and 12 show ignition energization overlap determination methods. FIG. 10 shows a case where the successive ignition energization signals IGT (n−1) and IGT (n) do not overlap, and FIG. 11 shows the ignition energization signals IGT (n−1) and IGT (n). Indicates the case of overlapping. As shown in FIG. 12, when the overlap is determined, the energization start timing value and the ignition timing value that are ignited and output in accordance with the angle timer are used, and the n cylinder energization start timing value and the (n-1) cylinder ignition timing value are determined. The determination is performed using the angle difference as a determination value.
[0046]
In consideration of the turn-back location of the angle counter, when the subtraction value (angle difference) of the (n-1) cylinder ignition timing value becomes negative from the n-cylinder energization start timing value, it is corrected with the one-cycle value of the angle counter. To do.
[0047]
As shown in FIG. 11, when the energization timing of the (n-1) cylinder and the energization timing of the n cylinder overlap, the angular difference between the n-cylinder energization start timing value and the (n-1) cylinder ignition timing value. Becomes a negative value (the result of the operation is negative). In this case, the overlap determination flag is turned on. Also, the energization timing of the (n-1) cylinder does not overlap with the energization timing of the n cylinder, and the subtraction result of the (n-1) cylinder ignition timing value from the n cylinder energization start timing value is very small and enters the dead zone. In the case of an overlap, it is determined as an overlap. That is, it is determined that the ignition energization overlaps due to a hardware factor. On the other hand, as shown in FIG. 10, when the energization timing of the (n-1) cylinder and the energization timing of the n cylinder are sufficiently separated, the overlap determination flag remains off.
[0048]
Here, a comparison value for determining whether or not the vehicle is in the dead zone is obtained from the engine speed at that time. Specifically, since the above-mentioned maximum delay time needs to be converted into an angle for comparison, a comparison value corresponding to the rotation speed is stored in advance as map data, and a comparison value corresponding to the rotation speed at that time is calculated. This comparison value decreases as the engine speed increases.
[0049]
The comparison value may be a value (fixed value) obtained by converting the maximum delay time Td into an angle at the maximum rotational speed. In other words, when the response delay due to the hardware configuration is converted to an angle value when the fixed value is set, if the value is converted to the angle at the maximum rotation speed, the comparison value at the time of low rotation is longer than the maximum delay time in terms of time Since it will be time, there will be no practical problems. Further, in this example, when ignition is cut upon receiving a request for forced misfire, etc. during traction control, the energization start timing value and the ignition timing value are set to absolute angular positions corresponding to ATDC 30 ° CA where ignition has ended. System configuration. Therefore, if the energization start timing of the n cylinder matches the ignition timing, it is determined that the energization of the n cylinder has been cut and it is determined that there is no overlap.
[0050]
The place where the overlap determination is performed is a place where ignition in the previous cylinder (n−1) with respect to the predetermined cylinder n always ends. In this embodiment, since ignition is output by angle control, the energization start timing value and the ignition timing value are stored as absolute angles. Further, when ignition is completed, the store value is changed (initialized) to an angle at which ignition is not performed once for safety, and therefore, determination is made before initialization after the ignition end position. As a result, by performing the overlap determination with the angular period interrupt corresponding to this place, it is not necessary to newly generate an interrupt at every energization start or every ignition timing, so that an increase in processing load can be prevented. . Furthermore, when the ignition is cut, it is initialized, so that it can be surely determined if it is determined at this place. It should be noted that the determination logic of this embodiment can determine the place where the determination is made when there is a limitation in the IGF detection specification even if the energization start or energization end interrupt is made.
[0051]
In FIG. 11, the overlap determination is performed at the timing of t20, and this position is ATDC 30 ° CA after the most retarded position of the (n−1) cylinder. Further, by turning off the overlap determination flag immediately after performing the IGF fail determination, it is possible to determine a plurality of cylinders with one determination flag, and to prevent an increase in memory. In FIG. 11, the overlap determination flag is turned off at the timing t21, and this position is ATDC 66 ° CA.
[0052]
FIG. 13 is a flowchart of the ignition energization overlap determination, and the details will be described with reference to FIG.
In the angular cycle interruption every 36 ° CA, the CPU 11 determines in step 100 whether or not each cylinder is in the ATDC 30 ° CA position, and when each cylinder is in the ATDC 30 ° CA position, the CPU 11 performs overlap determination after step 101.
[0053]
First, in step 101, the CPU 11 obtains the energization start timing (angle) and ignition timing (angle) of the (n-1) cylinder, and in step 102 obtains the energization start timing of the n cylinder. In step 103, the CPU 11 determines whether or not the (n-1) cylinder energization start timing and the ignition timing are the same set value, and if the same set value, the (n-1) cylinder ignition is cut. It is determined that they are not overlapped, and the process is terminated. On the other hand, when the set values are not the same in step 103, the CPU 11 proceeds to step 104 and calculates the overlap determination value by subtracting the (n-1) cylinder ignition timing from the energization start timing of the n cylinder.
[0054]
Since the angle counter is a ring counter for one cycle of 720 ° CA, the CPU 11 corrects the return position of the counter by adding 720 ° CA in step 105 when the subtraction result in step 104 is negative. Further, in step 106, the CPU 11 determines whether or not the overlap determination value is negative or between “0” and a predetermined value (comparison value) ΔT. When this condition is satisfied, there is a possibility that the energizations overlap including the response delay of the circuit. That is, there is a possibility that the ignition energization signals (energization periods) that follow each other overlap or are close within a predetermined period width and overlap. In other words, if the overlap determination value is larger than the angle conversion value of the maximum delay time Td at the number of rotations at that time, it is determined that there is no overlap.
[0055]
When the condition described above is satisfied in step 106, the CPU 11 proceeds to step 107 and turns on the overlap determination flag (timing t20 in FIG. 11). Further, if the condition described above is not satisfied in step 106, the CPU 11 terminates assuming that there is no overlap.
[0056]
On the other hand, in step 108, the CPU 11 determines whether or not it is ATDC 66 ° CA, and when it is ATDC 66 ° CA, the CPU 11 proceeds to step 109 and determines whether or not the overlap determination flag is on. If the overlap determination flag is off, the CPU 11 proceeds to step 110 and performs a failure determination of the ignition confirmation signal IGF. If the overlap determination flag is ON in step 109, the CPU 11 does not perform the IGF fail determination in step 110, and proceeds to step 111 and turns off the overlap determination flag for determining the next cylinder (t21 in FIG. 11). Timing).
[0057]
Thus, the present embodiment has the following features.
(A) The CPU 11 determines whether or not adjacent ignition energization signals overlap or are close within a predetermined period width by executing the processing of FIG. 13 (steps 100 to 106). When the distance is within the range, the overlap determination flag is turned on (step 107), and the abnormality determination of the ignition output based on the ignition confirmation signal IGF is prohibited (cancelled) (steps 108 to 111, specifically overlap). Step 110 is bypassed when the determination flag is on). In other words, the ignition output circuits 20 and 30 and the igniter circuit indicate that the actual energization overlaps the ignition output system capable of overlapping the ignition energization without determining only by the output state of each cylinder in the microcomputer 10. By determining in consideration of the response delays 201 and 202, even when the CPU calculation value and the port output state are not overlapped, it is possible to reliably determine even when the actual energization is overlapping.
[0058]
In this way, in the system that outputs the ignition energization signal independently for each cylinder and receives the ignition confirmation signal IGF on the common line, the ignition confirmation can be reliably performed.
(B) The dead zone indicating that the ignition energization signals that follow each other are close to each other within a predetermined period width includes at least the response delay of the input / output circuits 20 and 30 and the internal circuits 201 and 202 of the igniter. preferable.
(C) The determination that the ignition energization signals that precede and follow each other overlap or are close to each other within a predetermined period width is made based on the difference between the energization start timing in the predetermined cylinder and the ignition timing of the preceding ignition target cylinder. Therefore, it is preferable for practical use.
(D) The timing for determining whether the ignition energization signals that precede and follow each other overlap or are close to each other within a predetermined period width is the timing at which ignition in the previous ignition target cylinder is necessarily terminated (specifically, ATDC 30 ° for each cylinder) CA), which is practically preferable.
(E) A hard crank 100 (at least an edge time measuring counter 103 as a pulse interval measuring means, a multiplying counter 105 as a multiplying signal generating means, and an ignition angle counter 110 that performs a counting operation based on a multiplying clock (multiplied signal)). The energization start position and the energization cut-off position (ignition timing) obtained by the CPU 11 as the setting means are compared with the count value of the ignition angle counter 110 by the microcomputer 10 including the ignition energization signal output means. Is output. Therefore, a system that generates a multiplied clock (multiplied signal) at a predetermined angular interval to synchronize with the engine rotation eliminates the need for calculation for conversion from angle to time, thereby reducing the processing load. In addition, the ignition energization signal (energization start timing and ignition timing) can be set at the crank angle, so that highly accurate ignition control and more reliable ignition confirmation can be performed with almost no influence from the acceleration / deceleration of the vehicle. it can.
[0059]
In the description so far, the ignition control is described as a system that performs hard ignition by matching the angle with the angle counter, but it is also possible to determine overlap by ignition control using a time timer. When igniting with this time timer, since the angle from the current time to the start of energization or the place where ignition is desired is converted to time, ignition is performed, so the absolute position of the ignition angle of each cylinder is unknown, so as an overlap determination method First, a method of converting the relative angle from TDC to an absolute angle between 720 ° CA and comparing is conceivable. In this method, since the output is controlled by time, the ignition calculated by the angle during acceleration / deceleration is possible. Since an error occurs in actual ignition, the comparison value (determination of the dead zone) is set to a larger value in consideration of acceleration / deceleration in the circuit constant. More specifically, a history of the rotational speed is taken, and a correction is applied to the comparison value when the rotational speed does not change from the tendency of the rotational speed (change in rotational speed).
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an ignition timing control device for an engine in an embodiment.
FIG. 2 is a time chart for one engine cycle (720 ° CA).
FIG. 3 is a configuration diagram of a hard crank.
FIG. 4 is a time chart for explaining generation of an angle clock by a hard crank.
FIG. 5 is a time chart for explaining an angle counter, a down counter, and an ignition output.
FIG. 6 is a time chart for explaining generation of an ignition confirmation signal.
FIG. 7 is a time chart for explaining monitoring of an ignition confirmation signal.
FIG. 8 is a time chart for explaining monitoring of an ignition confirmation signal when ignition output overlaps;
FIG. 9 is a time chart for explaining signal delay.
FIG. 10 is a time chart for explaining an overlap determination method.
FIG. 11 is a time chart for explaining an overlap determination method;
FIG. 12 is a time chart for explaining an overlap determination method;
FIG. 13 is a flowchart for explaining the operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine control ECU, 10 ... Microcomputer, 11 ... CPU, 16 ... Timer module, 100 ... Hard crank, 103 ... Edge time measurement counter, 104 ... Multiplication register, 105 ... Multiplication counter, 108 ... Reference register, 109 ... Tracking counter 110 ... An ignition angle counter.

Claims (5)

In the engine ignition timing control device that outputs an ignition energization signal to each cylinder independently to the igniter and receives an ignition confirmation signal corresponding to the ignition energization signal in a common line in the igniter,
An ignition timing control apparatus for an engine, characterized by prohibiting an abnormality determination of an ignition output based on an ignition confirmation signal when successive ignition energization signals overlap or are close within a predetermined period width. 2. The engine according to claim 1, wherein the dead zone indicating that the successive ignition energization signals are close within a predetermined period width includes at least a response delay of the input / output circuit and the internal circuit of the igniter. Ignition timing control device. The determination that the successive ignition energization signals overlap or are close within a predetermined period width is made based on the difference between the energization start timing in the predetermined cylinder and the ignition timing of the preceding ignition target cylinder. 2. The ignition timing control device for an engine according to claim 1, wherein 4. The timing for determining whether successive ignition energization signals overlap or are close within a predetermined period width is a timing at which ignition in the previous ignition target cylinder is necessarily terminated. Engine ignition timing control device. Pulse interval measuring means for measuring a pulse interval by inputting a crank signal of a pulse train at predetermined angular intervals corresponding to rotation of the crankshaft of the engine;
Based on the current pulse interval by the pulse interval measuring means, a multiplied signal generating means for generating a multiplied signal of an integer multiple frequency by the next pulse,
An ignition angle counter that counts based on the multiplication signal;
Setting means for setting an energization start angle position and an energization cutoff angle position of the ignition energization signal;
An ignition energization signal output means for comparing the count value of the ignition angle counter with the energization start angle position and the energization cutoff angle position and outputting an ignition energization signal according to the comparison result;
The engine ignition timing control device according to any one of claims 1 to 4, further comprising:

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