JPH07217489A - Cpu interruption load reduction device - Google Patents

Abstract

PURPOSE:To provide an average pulse period capable of reducing a CPU interruption load and free from the fluctuation of an engine speed. CONSTITUTION:CPU saves a time ICR, whenever an interruption demand is received for every last transition edge of a rotation signal, in the state where an interruption control timer counts the preset time TO or more (step S600). When the interruption is judged to be due to detection with a gear section (step S600), a gear section detection period T180 is obtained on the basis of the time Z180i previously detected with the section, and the currently detected time Z180i (step S606). In this case, the gear section is provided to suit the fluctuating period of an engine speed. Thus, a period free from the effect of the fluctuation can be obtained. Furthermore, an engine speed can be obtained from the period detected with the gear section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CPU (Central Processing Unit) interrupt load reducing device, and more particularly, the present invention relates to obtaining an average pulse period which is not affected by the swell of engine speed.

[0002]

2. Description of the Related Art Conventionally, as such a field, Japanese Patent Laid-Open No. 1-1
A CPU interrupt load reducing device described in Japanese Patent No. 11202 is known. This describes a technique relating to the cycle calculation of a pulse signal in a CPU used for controlling an engine. In particular, it describes a system capable of stably calculating the pulse period even at high engine speed. The details of the interrupt of this system will be described below with reference to FIG.

FIG. 9 is a time chart showing a cycle calculation process executed by the CPU interrupt load reducing device described in the above publication. As shown in this figure, in this system, an interrupt request signal generated when the next engine rotation signal NE falls after the time T0 or more by the interrupt inhibit timer of this figure (c) As shown
Enter interrupt processing. And once interrupt processing (this figure (d)
(See (c) of this figure) after the execution of
Since the interrupt disable timer time is not T0,
Even if the interrupt request signal is generated again at the fall of the engine rotation signal NE, the interrupt processing by this signal is not executed. Further, at this time, the number of pulses (see (a) of this figure) generated from the execution of the interrupt process to the elapse of the predetermined time T0 is counted. Further, the value (time) of the free-run counter when the interrupt processing is executed is stored. That is, according to this configuration, when an interrupt is generated by the pulse input at the time Cn−1 by the free-run counter of FIG. 7E, the interrupt request is prohibited for a predetermined time after that, and the number of pulses P0 generated during that time is generated.
(See this figure (a)) is counted. Since an interrupt is generated by the pulse input at time Cn after a predetermined time has elapsed, the average pulse period Tn during this period is Tn = (Cn
It can be calculated as −Cn−1) / P0. For this reason, since it is not necessary to calculate the cycle for each pulse input, the pulse cycle can be calculated even if the pulse input cycle becomes short when the engine is rotating at high speed, and the interrupt load on the arithmetic processing of the CPU is reduced. .

[0004]

By the way, when the engine speed is used for engine control, the engine speed undulates depending on the stroke of the cylinder. When an interrupt request is made at regular time intervals as shown in FIG. 6D, the average pulse period measured is affected by the swell of the engine speed. That is, the CPU
Since the average pulse period obtained by the interruption load reduction device includes the influence of the swell of the engine speed, the engine speed obtained by this reciprocal varies. In order to eliminate the influence of the swell of the engine speed, as shown in FIG. 9, one operating stroke of the cylinder of the engine is divided by the number of cylinders (the number of cylinders) or at an angle interval of 2 times n. Is an integer), that is, for a 4-cycle engine, the cycle of crankshaft 720 ° CA / cylinder number, for example, 180 ° CA for 4 cylinders, should be measured and the engine speed calculated. For this purpose, it is only necessary to be able to measure the cycle from one incisor tooth indicating the reference position of the engine rotation signal NE to the next incisor tooth. Thus, as shown in FIG. 9, the free running counter Cm-
It is necessary to find the difference between 1 and Cm. Prior art CPU
According to the interrupt load reduction device, Cm-
Even if the interrupt request at 1 and the time can be stored, the interrupt request at the timing of Cm and the time cannot be surely stored. Therefore, there is a possibility that the above-mentioned 180 ° CA period may not be measured.

Therefore, in view of the above problems, it is an object of the present invention to provide a CPU interrupt load reducing device capable of surely obtaining an average pulse period which is not affected by the swell of the engine speed.

[0006]

In order to solve the above-mentioned problems, the present invention provides a pulsar which rotates in conjunction with the rotation of an engine, as shown in FIG. A characteristic part having a plurality of teeth at equal intervals around the plate and corresponding to a predetermined number of teeth at each angular interval obtained by dividing one operation stroke of the engine by the number of cylinders or a divisor of the number of cylinders. And a rotation angle sensor for detecting rotation of the disk based on interaction of a plurality of teeth by rotation of the pulsar, a time measuring means for measuring time, and a rise of pulse of the rotation speed sensor or An edge detection unit that detects a falling edge, an interrupt control unit that receives an edge detection signal from the edge detection unit and issues an interrupt request, and an interrupt request from the interrupt control unit that suspends normal operation, Department If it is a later interrupt, and if it is determined that it is an interrupt immediately after the characteristic part, the current time is read as the characteristic part detection time from the clocking means and stored, and the current characteristic part detection time and the previous characteristic part detection time are compared. A CPU that calculates a characteristic part detection cycle from the deviation, and an interrupt prohibition that prohibits input of an edge detection signal from the edge detection means to the CPU for a predetermined time after the interrupt control means makes an interrupt request. And a means for setting the predetermined time to be shorter than a time width obtained by time-converting the width of the characteristic portion at a predetermined maximum engine speed.

Further, according to a second aspect of the present invention, the edge detection signal generated within the predetermined time after the interrupt control means makes an interrupt request to the CPU interrupt load reduction device is counted and repeated. The CPU further includes counting means, and the CPU reads and stores the current time as the interrupt time from the time measuring means each time an interrupt is generated by the interrupt request, and stores the current time and the interrupt time at the previous interrupt time. A means for determining the cycle, determining the average cycle of the edge detection signal from the count value of the counting means and the interrupt cycle, comparing the average cycle of this time and the previous time, and determining whether the interrupt is immediately after the characteristic part, It may be included.

Further, as the characteristic portion, as in claims 3 and 4, an incisor having no teeth corresponding to the predetermined number of teeth may be used, or a tooth corresponding to the predetermined number of teeth may be provided. It may be a long tooth formed as one tooth.

[0009]

According to the CPU interrupt load reducing device of the present invention, in principle, an interrupt request is made by an edge detection signal. However, even if an edge detection signal is received, the CPU is interrupted for a predetermined time after making an interrupt request. Interrupts are prohibited and the processing load on the CPU is reduced. Further, since the predetermined time is set to be shorter than the time width obtained by time-converting the width of the characteristic portion at the predetermined maximum engine speed, the edge detection signal by the first tooth next to the characteristic portion, that is, , The interrupt request is surely sent to the CPU at the timing of Cm in FIG. Therefore, one operation stroke of the engine is divided by the number of cylinders or a divisor of the number of cylinders, that is, every angular interval of the engine speed (for example, 180 ° CA for a four-cylinder engine). The pulse period can be measured reliably. Therefore, it is possible to reliably measure the average pulse period that is not affected by the swell of the engine speed while sufficiently reducing the interrupt load on the CPU.

Further, in the CPU interrupt load reducing device according to the second aspect, a C and a means different from the CPU are used.
The number of edge detection signals for a predetermined period during which interrupts to the PU are prohibited is counted, and the CPU is interrupted by the next interrupt after the predetermined time has elapsed.
By calculating the average period of the edge detection signal using the count value of the counting means, and further determining the change in the average period, the characteristic part can be reliably identified, and the period of the swell of the engine speed can be measured. It can be done reliably with a series of processes. In addition, since the CPU does not perform interrupt processing for a predetermined time at most even if the CPU processes each interrupt processing at most, the overall load on the CPU is reduced, especially in the high engine speed region. The processing load will be extremely reduced.

Further, as the characteristic portion, as described in claim 3, by adopting cutting teeth having no teeth corresponding to the predetermined number of teeth, one operation stroke of the engine is determined by the number of cylinders or the number of cylinders. A rotation angle divided by a divisor of a number may be detected by a rotation speed sensor.
The number of teeth corresponding to the predetermined number of teeth as described in 1.
It may be a long tooth formed as one tooth.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a fuel injection control device for a diesel engine according to an embodiment of the present invention. As shown in the figure, an overflow type distribution type fuel injection pump 1 includes a drive pulley 3 drivingly connected to a crankshaft 40 of a diesel engine 2 through a belt or the like so as to make one rotation by two rotations of the crankshaft. It is provided and driven by the rotation of the drive pulley 3. Then, the fuel is pressure-fed to the fuel injection nozzles 4 provided between the cylinders of the diesel engine 2 (four cylinders in this case) to inject the fuel.

In the fuel injection pump 1, the drive pulley 3 is attached to the tip of the drive shaft 5. Further, in the middle of the drive shaft 5, a fuel feed pump (90
6 has been provided). A disk-shaped gear (pulsar) 7 is attached to the base end side of the drive shaft 5.

FIG. 2 is a diagram showing the configuration of the pulsar 7 of FIG. As shown in the figure, on the outer peripheral surface of the pulsar 7, the same number of cutting teeth 7a as the number of cylinders of the diesel engine 2, that is, four cutting teeth 7a as characteristic portions are formed at equal angular intervals (in this case, "90 °"). Further, 21 protrusions (teeth) 7b are formed at equal intervals (in this case, “7.5 °”) between each cutting tooth 7a (84 in total). Returning to FIG. 1, the base end of the drive shaft is connected to the cam plate 8 via a coupling (not shown).

A roller ring 9 is provided between the pulsar 7 and the cam plate 8, and a plurality of cam rollers 10 are mounted along the circumference of the roller ring 9 so as to face the cam face 8a of the cam plate 8. There is. The cam faces 8a are provided in the same number as the number of cylinders of the diesel engine 2. The cam plate 8 is constantly urged and engaged with the cam roller 10 by the spring 11.

A base end of a fuel pressurizing plunger 12 is integrally rotatably attached to the cam plate 8, and the cam plate 8 and the plunger 12 are rotated in association with the rotation of the drive shaft 5. That is, the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via the coupling. As a result, the cam plate 8 is engaged with the cam roller 10 while rotating, and is reciprocally driven in the left-right direction in the figure by the same number as the number of cylinders. Further, the plunger 12 is reciprocally driven in the same direction while rotating with the reciprocating motion. That is, the plunger 12 is moved forward (shifted) while the cam face 8 a of the cam plate 8 rides on the cam roller 10 of the roller ring 9. On the contrary, the plunger 12 is moved back while the cam face 8a rides down the cam roller 10.

The plunger 12 is fitted in a cylinder 14 formed in the pump housing 13, and a high pressure chamber 15 is provided between the tip end surface of the plunger 12 and the bottom surface of the cylinder 14.
Has become. Also, on the outer periphery of the tip of the plunger 12,
The same number of intake grooves 16 and distribution ports 17 as the number of cylinders of the diesel engine 2 are formed. Also, those suction grooves 1
6 and the distribution port 17, corresponding to the pump housing 1
A distribution passage 18 and a suction port 13 are formed at 3.

Then, the drive shaft 5 is rotated to drive the fuel feed pump 6, whereby fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. Further, during the intake stroke in which the plunger 12 is moved back and the high pressure chamber 15 is decompressed, one of the intake grooves 16 communicates with the intake port 19 so that fuel is introduced from the fuel chamber 21 to the high pressure chamber 15. . on the other hand,
During the compression stroke in which the plunger 12 is moved forward and the high-pressure chamber 15 is pressurized, fuel is pressure-fed and injected from the distribution passage 18 to the fuel injection nozzle 14 of each cylinder.

In the pump housing 13, a spill passage 22 for fuel overflow (spill) is formed which connects the high pressure chamber 15 and the fuel chamber 21. In the middle of the spill passage 22, a well-known electromagnetic spill valve (S
PV) 23 is provided. This electromagnetic spill valve 23 is a normally open type valve, and when the coil 24 is in the non-energized (off) state, the spill passage 22 is opened by the valve body 25 and the pressurized fuel in the high pressure chamber 15 overflows into the fuel chamber 21. Then, the fuel pressure feed from the fuel injection pump 1 is stopped. When the coil 24 is energized (turned on), the valve body 25 closes the spill passage 22. For this reason, the overflow of the pressurized fuel from the high pressure chamber 15 to the fuel chamber 21 is blocked, and the fuel pressure pumping from the fuel injection pump 1 is allowed.

Therefore, by controlling the energization time of the electromagnetic spill valve 23, the valve 23 is controlled to be closed / opened, and the amount of fuel overflow from the high pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel inside the high pressure chamber 15 is depressurized and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward, the fuel pressure in the high pressure chamber 15 does not rise while the electromagnetic spill valve 23 is open, and fuel injection from the fuel injection nozzle 4 is not performed. Further, during the forward movement of the plunger 12, the fuel injection amount from the fuel injection nozzle 4 is controlled by controlling the timing of opening the electromagnetic spill valve 23.

Below the pump housing 13, there is provided a timer device (which is expanded 90 degrees in this figure) 26 for controlling the fuel injection timing. This timer device 26
Controls the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5. This controls the timing at which the cam face 8a of the cam plate 8 engages with the cam roller 10, that is, the timing at which the cam plate 8 and the plunger 12 reciprocate.

The timer device 26 is differentially operated by hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a low pressure chamber 29 on one side of the timer housing 27. And a timer spring 31 for pressing and urging the timer piston 28 toward the pressure chamber 30 on the other side. The timer piston 28 is connected to the roller ring 9 via the slide pin 32.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 is determined by the equilibrium relationship between the fuel pressure and the urging force of the timer spring 31. Further, by determining the position of the timer piston 28, the roller ring 9
Is determined, and the reciprocating timing of the plunger 12 is determined via the cam plate 8.

In order to control the fuel pressure of the timer device 26, in order to control the fuel pressure of the timer device 26, the timer device 26 is provided with a timing control valve 33. That is, the pressurizing chamber 30 and the low pressure chamber 29 of the timer housing 27 are communicated with each other by the communication passage 34, and the timing control valve 33 is provided in the middle of the communication passage 34. The timing control valve 33 is an electromagnetic valve that is opened / closed by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening / closing control of the valve 33. The lift timing of the plunger 12 is controlled by the fuel pressure adjustment, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

A rotation speed sensor 35 including an electromagnetic pickup coil is attached to the upper portion of the roller ring 9. As shown in FIG. 2, the rotation speed sensor 35 is attached so as to face the outer peripheral surface of the pulsar 7, and the unit rotation angle detecting means is constituted by the both 35 and 7. Then, when the cutting teeth 7a and the teeth 7b as the characteristic parts of the pulsar 7 cross just below the rotation speed sensor 35, their passage is detected, and the engine rotation speed Ne and a predetermined unit rotation angle (7) of the engine rotation angle (7) are detected. A rotation angle signal (rotation angle pulsar) is output every 0.5 ° CA. Further, since this rotation speed sensor 35 is integrated with the roller ring 9, it outputs a rotation angle signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

Next, the diesel engine 2 will be described. In the diesel engine 2, a cylinder 41, a piston 42, and a cylinder head 43 form a main combustion chamber 44 corresponding to each cylinder. Also,
Each of the main combustion chambers 44 is connected to an auxiliary combustion chamber 45 that is also provided corresponding to each cylinder. Then, the fuel is supplied to each sub-combustion chamber 45 by being injected from each fuel injection nozzle 4. A well-known glow plug 46 as a start-up assist device is attached to each sub-combustion chamber 45.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 50, respectively. The intake pipe 47 is provided with a compressor 49 of a turbocharger 48 that constitutes a supercharger. Further, the exhaust pipe 50 is provided with a turbine 51 of the turbocharger 48. Further, the exhaust pipe 50 is provided with a waste gate valve 52 for adjusting the supercharging pressure. As is well known, the turbocharger 48 uses the energy of exhaust gas to rotate a turbine 51, and rotates a compressor 49 coaxially with the turbine 51 to increase the pressure of intake air. This is to increase the output of the diesel engine 2 by sending it to the main combustion chamber 44 to burn a large amount of fuel.

Further, the diesel engine 2 is provided with a recirculation pipe 54 for recirculating a part of the exhaust gas in the exhaust pipe 50 to the intake port 53 of the intake pipe 47. This reflux pipe 54
An exhaust gas recirculation valve (EGR valve) 55 for adjusting the amount of exhaust gas recirculation is provided midway. The EGR valve 55 is opened / closed by controlling a vacuum switching valve (VSV) 56.

Further, in the middle of the intake pipe 47, there is provided a throttle valve 58 which is opened / closed in association with the depression amount of the accelerator pedal 57. A bypass passage 59 is provided in parallel with the throttle valve 58, and a bypass throttle valve 60 is provided in the bypass passage 59. The bypass throttle valve 60 is controlled to be opened / closed by an actuator 63 having a two-stage diaphragm chamber driven by the control of two VSVs 61 and 62. The bypass throttle valve 60 is controlled to open and close according to various operating states. For example, during idle operation, it is controlled to a half-open state to reduce noise and vibrations, during normal operation it is controlled to a fully open state, and when operation is stopped, it is controlled to a fully closed state for safety.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, the timing control valve 33, the glow plug 46, and the VSVs 56, 61, 62 are electrically connected to an electronic control unit (hereinafter simply referred to as “ECU”) 71. The ECU 71 controls the drive timings thereof.

The following various sensors are provided as sensors for detecting the operating state. That is, the intake pipe 47
An intake air temperature sensor 72 for detecting the intake air temperature THA near the air cleaner 64 is provided in the. Also. An accelerator opening sensor 73 for detecting an accelerator opening ACCP corresponding to a required load of the diesel engine 2 is provided from the opening / closing position of the throttle valve 58. An intake pressure sensor 74 that detects the intake air pressure after supercharging by the turbocharger 48, that is, the supercharging pressure PiM, is provided near the intake port 53. Further, a water temperature sensor 75 for detecting the cooling water temperature THW of the diesel engine 2 is provided. Furthermore, a crank angle sensor 76 for detecting a predetermined crank angle that changes in proportion to the rotation speed of the crankshaft 40 of the diesel engine 2.
Is provided.

The above-mentioned sensors 72 to 76 are connected to the ECU 71, and the rotation speed sensor 35 provided in the fuel injection pump 1 is also connected to the ECU 71. Also, E
The CU 71, based on the signals output from the respective sensors 35, 72 to 76, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46 and the VSVs 56, 6
1, 62 and the like are preferably controlled.

FIG. 3 is a block diagram illustrating the configuration of the ECU 71 of FIG. As shown in the figure, the ECU 71 includes a timekeeping means 80, a central processing unit (CPU) 81, a read-only memory ROM) 82 in which a predetermined control program, maps, etc. are stored in advance, and a calculation result of the CPU 81, a measured value, etc. are temporarily stored. A random access memory (RAM) 83 that constitutes a measured value storage unit, a backup RAM 84 that stores previously stored data, and the like, and a logical operation circuit in which these units are connected to an input port 85, an output port 86, and the like by a path 87. Is configured as.

At the input port 85, the intake temperature sensor 72, the accelerator opening sensor 73, the intake pressure sensor 74,
The water temperature sensor 75 is used for each buffer 88, 89, 90, 9
1, the multiplexer 92, and the A / D converter 93. Similarly, the rotation speed sensor 35 and the crank angle sensor 76 described above are connected to the input port 85 via the waveform shaping circuit 94, and an interrupt processing unit described later is provided. The CPU 81 uses the input port 8
The detection signals from the respective sensors 35, 72 to 76, etc., which are input via 5 are read as input values. In addition, the output port 86 has respective drive circuits 95, 96, 97, 98, 99, 1
00 through electromagnetic spill valve 23, timing control valve 33, glow plug 46 and VSV 56, 6
1, 62, etc. are connected.

Then, the CPU 81 controls the sensors 35 and 72.
Electromagnetic spill valve 2 based on input values read from ~ 76
3, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62, etc. are suitably controlled.
FIG. 4 is a flowchart for obtaining an angle corresponding to the target fuel injection amount in the CPU 81 of FIG. 3 and converting the data into a predetermined unit angle and a remainder angle that are integral multiples. Figure 5
FIG. 5 is a diagram showing a timing chart regarding each data used for the calculation of FIG. 4.

As shown in the main routine of the software of FIG. 4, initialization is performed in step S500. In step S501, as shown in FIG. 5, 180 ° CA
The average engine speed NE is calculated from time T180 (details of calculation will be described later with reference to FIG. 7).

In step S502, the accelerator opening is calculated. In step S503, other operating states are calculated. In step S504, the basic injection amount QANG is calculated from the average engine speed NE and the accelerator opening.
As shown in FIG. 5, the target injection amount QANG is calculated as the angle data from NE0 to when the spill valve 23 is turned off, by correcting 0 according to other operating conditions.

In step S505, as shown in FIG. 5, 7.5 ° CA of the pulser 7 from the target injection amount QANG.
Number of teeth CNE of each projection (tooth) 7b and extra angle QANGRM
Is calculated as follows. QANG = CANG + QANGRM = CNE × 7.5 ° CA + QANGRM In step S506, control other than the basic injection control is performed, and then the process returns to step S501, which is the beginning of the main routine, and this control is repeated thereafter.

FIG. 6 is a diagram showing the functional blocks of the present invention. As shown in the figure, the input port section 85 of the ECU 71
The interrupt processing unit built in the edge detection unit 202 detects the rising or falling of the pulse of the rotation angle sensor 35 that detects the rotation of the disk based on the interaction of the teeth by the rotation of the pulsar 7. It has an interrupt control means 203 which receives an edge detection signal from the edge detection means 202 and makes an interrupt request. CP of ECU 71
The U81 stops the normal calculation in response to the interrupt request from the interrupt control unit 203, determines whether it is an interrupt immediately after the characteristic unit, and if it determines that the interrupt is immediately after the characteristic unit, the U81 determines the current time from the timer unit 80. It is read and stored as the part detection time, and the characteristic part detection cycle is calculated from the deviation between the current characteristic part detection time and the previous characteristic part detection time. Further, the interrupt processing unit is provided with the interrupt control means 2
An interrupt prohibiting means 204 is provided for prohibiting the input of the edge detection signal from the edge detecting means to the CPU 81 for a predetermined time after 03 makes an interrupt request. Further, the interrupt processing unit has a counting unit 205 that counts the edge detection signal generated within the predetermined time after the interrupt control unit 203 makes an interrupt request and repeats the count. The interrupt processing unit will be described in detail below.

The control process of FIG. 7 is a flow chart showing the control of the spill valve 23 (SPV) for fuel injection executed by the CPU 81 and the measurement of the cycle T180 of the crankshaft 180 ° CA, and FIG. 7 is a timing chart illustrating the control of No. 7. 7 is executed in response to an interrupt request output from an interrupt processing unit (not shown) built in the input port 85 based on the NE signal. According to the timing chart of FIG. 8, the interrupt control timer in the interrupt processing unit is set to a predetermined value. Next rotation signal N that has exceeded time T0
In response to the edge detection signal of the falling edge of E (NE12, 16, 20, 0), the interrupt processing unit is
The NE interrupt processing of FIG. 7 is executed. In particular, in this embodiment, the predetermined time T of the interrupt control timer
0 is set so that the angular interval of the cutting teeth 7a of the pulsar 7 is shorter than the time conversion value (time width T1) at the time of the maximum engine speed. For example, the maximum engine speed is 4
When the speed is 800 rpm, the number of pulses of the rotation signal NE is per 720 ° CA of the crankshaft (per 360 ° of the pass).
Assuming that the incisors also have teeth, the number of pulses is 96, and the number of incisors is 180 ° for each crankshaft 180 ° (every 90 ° for pulsar).
In the case of only the number of pieces (3 pulses), the time conversion value T1 between the falling edges at the incisor is T1 = [1 / {((4800 rpm / 2) / 60 s) ×
96}] × (3 + 1) ≈1042 μs, and if the timer T0 = 1024 μs, then T1> T0 is always satisfied if the engine speed is equal to or lower than the maximum speed.

Therefore, it is not known where the interrupt request is issued depending on the engine speed when the rotation signal is NE0 or more, but the interrupt request is always output when the rotation signal NE0 is generated and the next rotation is started from the rotation signal NE0 by the processing of FIG. 7 described below. Crankshaft 180 ° CA time T180 of signal NE0
Can be calculated reliably. Further, an input pulse counter IPC that counts the number of falling edges generated during a predetermined time T0 of the interrupt control timer is built in the above-mentioned interrupt processing unit, and the interrupt control timer NE is used as shown in the timing chart of FIG. Even while the interrupt processing is prohibited, the number of rotation signals NE (falling edges) generated is counted by the IPC, and the count value IPCR is used in the NE interrupt processing of FIG. 7 described later.

In the NE interrupt processing of FIG. 7, step S6
At 00, the value in the input capture register ICR in which the value of the free-run counter is written every moment is set to the counter start time (interrupt time) of the RAM 83.
Store in Ch. In step S601, the difference (interrupt cycle) between the present and previous count start times Cn and Cn-1 is stored in T1. Then, the rotation signal NE generated between the present and previous count start times Cn and Cn-1
Count value IP of the input pulse counter IPC indicating the number of
By dividing T1 by CR, the average period Tn of the pulses of the rotation signal NE, that is, the average period of the edge detection signal can be calculated.

In step S602, the count value IPCR of the input pulse counter IPC is added to NENO containing the order of the rotation signals up to the count at the time of the previous interrupt processing in order to obtain the number of the current rotation signal NE. In step S603, the rotation signal N obtained this time
The cycle Tn of E is the cycle Tn-1 of the rotation signal NE up to the previous time.
It is determined whether or not it is the NE interrupt processing by the detection signal of the falling edge of the rotation signal immediately after the incisor is detected by determining whether it is larger than 6/4 times. For example, if the previously interrupted NENO was the rotation signal NE20, the current Tn is Tn = 4 · Tn−1, and at worst, even if the previously interrupted NENO is the rotation signal NE17, Tn = 7. / 4 · Tn−1, and the incisors can be detected reliably. If it is determined that the tooth is an incision, the process proceeds to step S604 below, and NENO = 0 is set in step S604.

In step S605, the rotation signal NE
The occurrence time of 0 is stored in the Z180i of the RAM 83 from the register ICR as the incisor tooth detection time. Step S60
6, the difference between the present time and the previous generation time (cutting tooth detection time) of the rotation signal NE0 stored in Z180i and Z180i-1, that is, the cutting tooth detection cycle is set to 180
It is stored in T180 of the RAM 83 as the CA time.

In step S607, the spill valve (SP) in which fuel is sent to the engine by the pressure feed of the plunger.
V) 23 is turned on, and the process proceeds to step S608. If no cutting tooth is detected in step S603, the process proceeds to step S608 without passing through the above steps S604 to 607. In step S608, NEN
To determine whether O is before the timing of the OFF operation of the spill valve 23, the number of teeth NE calculated in the process of FIG.
When NO is compared with NO, and if NENO ≦ CNE, it is determined in step S609 that the spill valve 23 is before the OFF operation timing, and the time TSPVOFF until the spill valve 23 OFF operation is calculated as follows.

TSPVOFF = (CNE-NENO) ×
T180 / 24 + (QANGRM / 7.5) x T180 / 24 where (CNE-NENO) x T180 / 24 is used to calculate the time from the current engine NE to CNE, and (QAN
The time of QANGRM is calculated by GRM / 7.5) × T180 / 24.

In step S610, the register IC
TSPVOFF is added to the value of the register ICR, which is the time when the current rotation signal NE is stored in R, and the spill valve 23 is added.
ZSPVOFF is calculated as the OFF time of. In step S611, the output compare register OC
By setting the time to R and setting the OFF state of the port of the spill valve 23, the spill valve 23 is turned off at the time when the target injection amount is reached.

In step S612, step S6
When NENO is larger than CNE in 08, it is determined that the spill valve 23 has already passed the OFF state time, and the spill valve 23 is turned OFF to end the processing. By executing the above processing, the interrupt process is reliably executed in the incisor portion (characteristic portion), so that the incisor portion detection time can be obtained for each incisor portion. Further, the cutting tooth detection period can be reliably obtained from the cutting tooth detection time detected last time and the cutting tooth detection time detected this time. This cutting tooth portion is provided for each cycle of the swell of the engine speed. Therefore, by obtaining the engine speed from the detection cycle of the cutting tooth portion, the engine speed that is not affected by the swell of the engine speed is obtained. be able to.

Further, in step S603, the cycle Tn of the rotation signal NE obtained this time is the rotation signal NE up to the previous time.
By determining whether it is larger than 6/4 times the cycle Tn−1 of the above, it is determined whether the NE interrupt processing is performed by the detection signal of the falling edge of the rotation signal immediately after the incisor is detected. As a result, it is possible to reliably detect the NE interrupt process immediately after the incisor portion.

FIG. 10 is a diagram showing the configuration of a pulsar according to another embodiment. In the embodiment described above, the characteristic portion is the incisor Ta.
However, as shown in FIG. 10, long teeth 7a ′ may be formed by forming a predetermined number of teeth as one tooth. Further, the relationship between the length of the characteristic portion (cutting tooth portion or long tooth portion) and the predetermined time of the interrupt control timer may be such that the length of the characteristic portion> the predetermined time of the interrupt control timer. That is, the predetermined time of the timer may be set according to the length of the characteristic portion, or the length of the characteristic portion may be set according to the predetermined time of the timer.

As a result of the above operation, at the time of high engine speed, the generation of NE interruptions is reduced and the interruption load of software is reduced as compared with the conventional case, and the average rotational speed NE for calculating the basic injection amount is calculated. It is possible to reliably measure the 180 ° CA cycle T180 required for

[0052]

As described above, according to the present invention, C
It is possible to reduce the interrupt load of the PU, to reliably detect the characteristic portion at each angular interval obtained by dividing one operation stroke of the engine by the number of cylinders or a divisor of the number of cylinders, and to reliably obtain the detection cycle of the characteristic portion. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a fuel injection amount control device for a diesel engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a pulser 7 in FIG.

FIG. 3 is a block diagram illustrating a configuration of an ECU 71 of FIG.

FIG. 4 is a flowchart for forming an angle corresponding to a target fuel injection amount into a predetermined unit angle that is an integral multiple and a remainder angle in the CPU 81 of FIG. 3;

FIG. 5 is a diagram showing a timing chart regarding angle data used for calculation in FIG. 4;

FIG. 6 is a diagram showing functional blocks of the present invention.

FIG. 7: Control of spill valve 23 (SPV) for fuel injection executed by CPU 81 and crankshaft 180 ° CA
It is a flowchart which shows the measurement of period T180.

FIG. 8 is a timing chart illustrating the control of FIG.

FIG. 9 is a time chart of an interrupt in the conventional CPU interrupt load reduction device.

FIG. 10 is a diagram showing a configuration of a pulsar according to another embodiment.

[Explanation of symbols]

 7 ... Pulsar 35 ... Rotation speed sensor 71 ... ECU 81 ... CPU

Claims (4)

[Claims] 1. A pulsar that rotates in association with the rotation of an engine, has a plurality of teeth at equal intervals around a disk, and has one operating stroke of the engine depending on the number of cylinders or the number of cylinders. A pulsar having a characteristic portion corresponding to a predetermined number of teeth for each angular interval divided by a divisor, and a rotation angle for detecting rotation of the disk based on interaction of a plurality of teeth by rotation of the pulsar. A sensor, a time measuring means for measuring time, an edge detecting means for detecting rising or falling of a pulse of the rotation speed sensor, an interrupt control means for receiving an edge detecting signal from the edge detecting means, and making an interrupt request. In response to an interrupt request from the interrupt control means, normal operation is stopped, and it is determined whether the interrupt is immediately after the characteristic part,
If it is judged that the interrupt is immediately after the characteristic part, the current time is read from the time measuring means as the characteristic part detection time and stored, and the characteristic part detection cycle is calculated from the deviation between the current characteristic part detection time and the previous characteristic part detection time. And a CPU for performing an interrupt request by the interrupt control unit,
And an interrupt prohibiting means for prohibiting the input of the edge detection signal from the edge detecting means to the CPU for a predetermined time, and the predetermined time is the width of the characteristic portion at a predetermined maximum engine speed converted into time. A CPU interrupt load reduction device characterized by being set to be shorter than a time width. 2. The interrupt control means further comprises counting means for counting the edge detection signals generated within the predetermined time after the interrupt request is made, and repeating the count, wherein the CPU is interrupted by the interrupt request. Each time it is performed, the current time is read as the interrupt time from the timekeeping means and stored, and the interrupt cycle is obtained from the interrupt time of this current interrupt time and the interrupt time of the previous field,
An average cycle of the edge detection signal is obtained from the count value of the counting means and the interrupt cycle, and the average cycle of this time and the previous time is compared to determine whether the interrupt is immediately after the characteristic part. The CPU interrupt load reduction device according to claim 1. 3. The CPU interrupt load reducing device according to claim 1, wherein the characteristic portion is an incisor having no teeth corresponding to a predetermined number of teeth. 4. The CPU interrupt load reducing device according to claim 1, wherein the characteristic portion is a long tooth in which a tooth corresponding to a predetermined number of the teeth is formed as one tooth.