JPH09242581A - Fuel injection timing control device for internal combustion engine - Google Patents

Abstract

(57) Abstract: When the engine speed suddenly changes, the control response delay of the spill valve is also corrected according to the elapsed rotation angle, so that no error occurs in the fuel injection amount. A plunger pump (12A) including a plunger (12) that pressurizes fuel includes a plunger pump (12).
A spill passage 22 that connects the high pressure chamber 15 of A and the low pressure side is formed, and a spill valve 23 is provided in the spill passage 22. The electronic control unit calculates the spill valve control command value as the spill valve actual operation time based on the engine operating state in the combustion cycle when the spill valve 23 is opened and closed, and the spill valve 23 is controlled by the spill valve control. The spill valve response delay is corrected and executed for the angle-time conversion value from the predetermined engine rotation angle position that is predicted based on the engine speed in the previous combustion cycle and that is based on the command value.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a diesel engine,
The present invention relates to a fuel injection timing control device for an internal combustion engine such as a gasoline engine.

[0002]

2. Description of the Related Art In recent years, with the development of electronic control technology, especially digital control technology, a so-called electronically controlled diesel engine has been put into practical use in which a fuel injection pump of a diesel engine is electronically controlled. There are various methods of electronically controlling the fuel injection pump, and one of them is to control the overflow of fuel in the fuel injection pump by an electromagnetic spill valve. This method is to adjust the fuel injection amount by opening the spill port by the electromagnetic spill valve at the overflow timing (spill timing) when the fuel injection amount reaches the target value, and ending the pressure feeding of the fuel.

More specifically, for example, in controlling the opening / closing of the electromagnetic spill valve, a constant crank angle (11.25 ° C.) of a diesel engine is usually detected by a rotation speed sensor.
Rotation angle signal (engine rotation pulse) output for each A)
Is used.

In this technique, as shown in FIGS. 11 and 12, a target spill timing corresponding to the operating state of the diesel engine is calculated, and a predetermined reference position of the engine rotation pulse (rise of the engine rotation pulse of "0"). To the target spill timing, the number of engine rotation pulses (8 in this case) and the surplus angle less than one pulse are obtained. Then, the required time of one pulse (engine rotation pulse of "8") including the target spill timing in the previous combustion cycle is set as a reference time, and this reference time is used to generate one pulse ("8" at the target spill timing in the current combustion cycle). Predict the required time (predicted pulse time) of the engine rotation pulse of ". Further, using the predicted pulse time and the unit angle (11.25 ° CA) which is the generation interval of the engine rotation pulse, the surplus angle is converted into time. Then, the valve opening command signal is output to the electromagnetic spill valve at a timing determined from the time conversion value and the number of engine rotation pulses to open the valve, thereby ending the fuel injection.

However, in this type of fuel injection timing control device, there is a delay in response from when the electromagnetic spill valve receives the valve opening command signal to when the electromagnetic spill valve actually opens, and there is a problem that the injection accuracy deteriorates.

In order to solve this problem, Japanese Patent Laid-Open No. 61-
In 226543, a fixed resistor having a resistance value corresponding to the valve opening delay time is provided, and the control circuit corrects corresponding to the response delay time of the electromagnetic spill valve based on the voltage signal Vτ prepared by the fixed resistor. The desired fuel injection amount Δτ is obtained. Then, the control circuit adds the fuel injection amount determined by the engine operating state and the fuel injection amount Δτ to be corrected, and applies the fuel injection amount to the electromagnetic spill valve in order to realize the fuel injection at the fuel injection amount determined by the engine operating state. The timing of the valve opening command signal is calculated.

[0007]

However, in the above technique, the response delay time of the electromagnetic spill valve is constant even if the engine speed (engine speed) is changed, but the elapsed crank angle (elapsed rotation angle) is different. Therefore, there is a problem that an error occurs in the injection amount when, for example, the engine rotation suddenly changes except in a specific operating state. That is, when the engine speed suddenly increases, the value of the elapsed crank angle becomes smaller, and conversely, when the engine speed suddenly decreases, the elapsed crank angle becomes larger. Therefore, when the engine rotation changes suddenly, there is a problem that the target spill time cannot be obtained.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to delay the control response of the spill valve even in a state other than a specific operating state such as when the engine speed suddenly changes. An object of the present invention is to provide a fuel injection timing control device for an internal combustion engine in which an error does not occur in the fuel injection amount by correcting the minute according to the elapsed rotation angle.

[0009]

In order to achieve the above object, the invention of claim 1 connects a plunger pump having a plunger for pressurizing fuel, and a pump chamber of the plunger pump and a low pressure side. In a fuel injection timing control device for an internal combustion engine, comprising a spill valve that opens and closes a fuel escape passage, and control means that controls the opening and closing of the spill valve, the control means controls the opening and closing of the spill valve when the internal combustion engine The gist is an injection timing control device for an internal combustion engine, which is characterized in that a spill valve response delay that is variable according to the engine speed is corrected.

According to a second aspect of the present invention, in the first aspect, the control means calculates a spill valve control command value as a spill valve actual operation timing based on an engine operating state in the combustion cycle, and controls the spill valve. , The spill valve response delay is corrected with respect to the angle-time conversion value from the predetermined engine rotation angular position, which is based on the spill valve control command value and is subjected to predictive correction based on the engine rotation in the past combustion cycle. The point is to do.

(Operation) According to the first aspect of the present invention, the control means corrects the spill valve response delay which is variable according to the engine speed of the internal combustion engine when the spill valve is controlled to open and close.
Even when the engine speed changes, the response delay time of the spill valve is constant, that is, it does not change, but the engine rotation angle changes as the engine speed changes. Therefore, by correcting the spill valve response delay by the control means,
There is no error in the fuel injection amount.

According to the invention of claim 2, the control means calculates the spill valve control command value as the spill valve actual operation timing based on the engine operating state in the combustion cycle, and the spill valve is controlled by the spill valve. The spill valve response delay is corrected with respect to the angle-time conversion value from the predetermined engine rotation angle position, which is predicted based on the engine rotation in the previous combustion cycle and is corrected based on the control command value.

Therefore, according to the second aspect of the invention, the control means uses the angle-time conversion value from the predetermined engine rotation angular position which is based on the spill valve control command value and which is predictively corrected based on the engine rotation in the previous combustion cycle. On the other hand, since the spill valve response delay is corrected, the spill valve response delay is also predicted and corrected, and no error occurs in the injection amount.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment applied to a diesel engine for automobiles as an internal combustion engine will be described below with reference to FIGS.
0 will be described in detail.

As shown in FIGS. 1 and 2, the fuel injection pump 1
Includes a drive pulley 3 drivingly connected to a crankshaft 40 of the diesel engine 2 via a belt or the like. Then, the fuel injection pump 1 is driven by the rotation of the drive pulley 3, and the fuel is pressure-fed to the fuel injection nozzle 4 as a fuel injection valve provided for each cylinder (four cylinders in this case) of the diesel engine 2. Fuel injection is performed.

In the fuel injection pump 1, the drive pulley 3 is attached to the tip of the drive shaft 5.
A fuel feed pump (developed by 90 degrees in the figure) 6 formed of a vane type pump is provided in the middle of the drive shaft 5. Further, a disc-shaped pulsar 7 is attached to the base end side of the drive shaft 5. The base end of the drive shaft 5 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. . Cam face 8a
Are provided as many as the number of cylinders of the diesel engine 2. Further, the cam plate 8 is always urged and engaged with the cam roller 10 by the spring 11.

A plunger pump 12 is provided on the cam plate 8.
The base end of the fuel pressurizing plunger 12 of A is integrally rotatably attached, and the cam plate 8 and the plunger 12 are attached.
Is rotated in association with the rotation of the drive shaft 5. That is, when the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via a coupling (not shown), the cam plate 8 rotates and engages with the cam roller 10, and the same number as the number of cylinders in the left-right direction in the drawing Is driven back and forth. Further, the plunger 12 is driven to reciprocate in the same direction while rotating with the reciprocation. That is, the plunger 12 is moved forward (lifted) while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, and vice versa.
The plunger 12 is moved back in the process of getting off.

The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and a high pressure chamber 15 as a pump chamber is provided between the tip end surface of the plunger 12 and the bottom surface of the cylinder 14. The plunger 12 and the cylinder 14 constitute a plunger pump 12A. In addition, on the outer periphery of the tip end side 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. A distribution passage 18 and a suction port 19 are formed in the pump housing 13 so as to correspond to the suction groove 16 and the distribution port 17.

Then, the drive shaft 5 is rotated and the fuel feed pump 6 is driven, 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 depressurized, 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 from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder and injected.

A spill passage 22 for fuel overflow (spill) is formed in the pump housing 13 as a fuel escape passage for communicating the high pressure chamber 15 with the fuel chamber 21. An electromagnetic spill valve 23 as a spill valve for adjusting fuel spill from the high pressure chamber 15 is provided in the middle of the spill passage 22. The electromagnetic spill valve 23 is a normally open type valve. When the coil 24 is not energized (off), the valve body 25 is opened and fuel in the high-pressure chamber 15 is spilled to the fuel chamber 21. When the coil 24 is energized (turned on), the valve body 25 is closed, and the spill of fuel from the high-pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by controlling the energization time of the electromagnetic spill valve 23, the valve 23 is closed / opened and the spill of fuel 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 in the high-pressure chamber 15 is reduced in pressure, and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward,
While the electromagnetic spill valve 23 is open, the fuel pressure in the high pressure chamber 15 does not rise and fuel is not injected from the fuel injection nozzle 4. Further, by controlling the timing of closing / opening the electromagnetic spill valve 23 during the forward movement of the plunger 12,
The injection end from the fuel injection nozzle 4 is adjusted to control the fuel injection amount.

Below the pump housing 13, a timer device (90 in the figure) for adjusting the phase of fuel injection (injection phase) with respect to the crank angle as a reference rotation angle.
26) is provided. The timer device 26 changes the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5 to change the timing at which the cam face 8a engages with the cam roller 10, that is, the reciprocating drive timing of the cam plate 8 and the plunger 12. It is for.

The timer device 26 is driven by control hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a low pressure on one side (left side in the drawing) of the timer housing 27. In the chamber 29, the timer piston 28 is composed of a timer spring 31 and the like that presses and urges the timer piston 28 to the pressurizing chamber 30 on the other side (the right side in the drawing). Then, the timer piston 28 has the slide pin 32.
It is connected to the roller ring 9 via.

The fuel pressurized by the fuel feed pump 6 is introduced into the pressurizing chamber 30. 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, the position of the roller ring 9 is determined by determining the piston position, and the reciprocating timing of the plunger 12 is determined via the cam plate 8.

The timer device 26 is provided with a timing control valve (TCV) 33 in order to adjust the fuel pressure acting as the control oil pressure of the timer device 26. Specifically, the pressurizing chamber 30 and the low pressure chamber 29 of the timer housing 27 are communicated with each other by a communication passage 34, and the TCV 33 is interposed in the communication passage 34. This T
The CV 33 is a solenoid valve that is opened and closed by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by adjusting the opening of the TCV 33. And
By adjusting the fuel pressure, the reciprocating timing of the plunger 12 is changed, and the injection phase of each fuel injection nozzle 4 is controlled.

On the upper part of the roller ring 9, a rotation speed sensor 35, which constitutes an engine rotation angle detecting means and a part of an operating state detecting means, is attached so as to face the outer peripheral surface of the pulsar 7. . The rotation speed sensor 35 is composed of an electromagnetic pickup coil, and outputs a detection signal each time a protrusion formed on the outer peripheral surface of the pulsar 7 crosses.

In this embodiment, as shown in FIG. 3, the pulsar 7 has two protrusions every 90 ° (180 ° CA in crank angle) from a state where 64 protrusions are arranged at equal intervals.
The toothless portion 7a is formed for each tooth. Therefore, when the crankshaft 40 of the diesel engine 2 rotates, an engine rotation pulse is output by each tooth every 720 ° CA / 64 = 11.25 ° CA, as shown by the detection output after waveform shaping in FIG. At the 14th engine rotation pulse, the tooth missing portion 7a causes 1
One engine rotation pulse (reference position signal) of 1.25 ° CA × 3 = 33.75 ° CA is output.

That is, on the outer peripheral surface of the pulsar 7, the same number of toothless portions 7a as the number of cylinders of the diesel engine 2 (four in this case) are formed at equal angular intervals, and between the toothless portions 7a adjacent to each other. Is formed with 14 protrusions (56 in total) at equal angular intervals. Therefore, by waveform-shaping the detection signal from the rotation speed sensor 35, the reference position signal synchronized with the fuel injection cycle and the rotation signal representing the rotation speed are obtained.

CNIRQ in FIG. 4 is a pulse counter (initial value 0) which indicates the number of engine rotation pulses after the reference position signal is output. Next, the diesel engine 2 will be described. As shown in FIG. 1, in this diesel engine 2, a cylinder 41 and a piston 4 are provided.
The main combustion chamber 44 corresponding to each cylinder is formed by 2 and the cylinder head 43. A sub-combustion chamber 45 communicating with each of the main combustion chambers 44 is provided for each cylinder. And, in each sub combustion chamber 45,
Fuel is injected from each fuel injection nozzle 4. A well-known glow plug 46 as a start 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. Further, the intake pipe 47 is provided with a compressor 49 of a turbocharger 48 that constitutes a supercharger, and the exhaust pipe 50 is provided with a turbine 51 of the turbocharger 48. The exhaust pipe 50 is provided with a waste gate valve 52 for adjusting the supercharging pressure PiM.

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. In the middle of the recirculation pipe 54, an exhaust gas recirculation valve (EGR valve) 5 for adjusting the recirculation amount of exhaust gas is provided.
5 are provided. The EGR valve 55 is opened and closed by 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 two VSVs 61 and 62.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, TCV33, glow plug 46 and each VSV56,
The electronic control units 61 and 62 are electrically connected to an electronic control unit (hereinafter simply referred to as “ECU”) 71, and their drive timing is controlled by the ECU 71.

As a sensor for detecting the operating state of the diesel engine 2, the following various sensors are provided in addition to the rotation speed sensor 35 described above. An intake air temperature sensor 72 for detecting the intake air temperature THA is provided near the air cleaner 64 provided at the inlet of the intake pipe 47.

Further, an accelerator opening sensor 73 for detecting the accelerator opening ACCP corresponding to the load of the diesel engine 2 is provided from the opening / closing position of the throttle valve 58. The accelerator opening sensor 73 constitutes a part of the operating state detecting means. An intake pressure sensor 74 that detects intake air pressure (intake pressure) PiM after supercharging by the turbocharger 48 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. Further, a crank angle sensor 76 for detecting a rotation reference position of the crankshaft 40, for example, a rotation position of the crankshaft 40 with respect to a top dead center (TDC) of a specific cylinder is provided. Further, the transmission (not shown) is provided with a vehicle speed sensor 77 for detecting the vehicle speed (vehicle speed) SP by turning on / off the reed switch 77b by a magnet 77a rotated by the rotation of the gear.

Each of the sensors 35, 72 to 77 described above is an EC
Each is connected to U71. Then, the ECU 71
Is based on the detection signals of the sensors 35, 72 to 77, the electromagnetic spill valve 23, the TCV 33, the glow plug 46 and the VS.
V56, 61, 62 are controlled.

Next, the structure of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 has a central processing unit (CPU) 81, a read-only memory (RO) storing a predetermined control program, a map, and the like in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the calculation result of the CPU 81, etc., and a backup RAM 84 for storing prestored data. These units, the input port 85 and the output port 86 are connected to the bus 87.
Connected by The CPU 81 constitutes control means, pulse time calculation means, rotation change amount calculation means, rotation change predicted value calculation means, operating crank angle calculation means, surplus angle calculation means, angle time conversion means, and predicted pulse time calculation means. ing. Further, the CPU 81 is adapted to perform a free running count operation for the calculation processing.

At the input port 85, the intake air temperature sensor 72, the accelerator opening sensor 73, the intake air pressure sensor 74, and the water temperature sensor 75 are connected to the buffers 88, 89, 90, 9 respectively.
1, a multiplexer 92 and an A / D converter 93. Similarly, the input port 85 is connected to the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 via a waveform shaping circuit 95. Then, the CPU 81 reads the detection signals of the sensors 35, 72 to 77 input via the input port 85 as input values. Each drive circuit 9 is connected to the output port 86.
6, 97, 98, 99, 100, 101, the electromagnetic spill valve 23, the TCV 33, the glow plug 46 and the VSV.
56, 61 and 62 are connected.

The CPU 81 uses the sensors 35 and 72.
Based on the input value read from ~ 77, the electromagnetic spill valve 2
3, TCV33, glow plug 46 and VSV56,6
1, 62 are preferably controlled.

In the present embodiment configured as described above, in order to calculate the timing (target spill timing) at which the electromagnetic spill valve 23 in the closed state is opened to cause the fuel to overflow.
Constant crank angle (11.25 ° C in this embodiment)
Engine rotation pulse output for each A) (see FIG. 10)
Is used. The valve opening timing of the electromagnetic spill valve 23 is given as an angle from a certain reference engine rotation pulse (the rising edge of the engine rotation pulse of the pulse counter CNIRQ = 0 in FIG. 10).

More specifically, from the rise of the engine rotation pulse of which the value of the pulse counter CNIRQ is "0" to the rise of the engine rotation pulse of "8", it is a direct angle, and in this case, it is calculated as the spill timing pulse number CANGL.

Further, the surplus angle θREM which is less than one pulse in the engine rotation pulse of “8” is converted into time as follows by prediction. That is, the time required for one pulse at the target spill timing in the previous combustion cycle is set as the reference time TS1125, and this reference time TS
1125 is used to predict the required time for one pulse including the target spill timing in the current combustion cycle, and the residual angle θREM is converted into time based on the predicted value (predicted pulse time TS1125a). The time-converted value is represented by the spill time TSPON.

Next, the calculation process of the spill time TSPON is shown in the flowchart of FIG. The calculation process of the reference time TS1125 is shown in the flowchart of FIG. The processing routine of FIG. 8 is executed at a predetermined timing, and the processing routine of FIG. 6 is executed by being interrupted by the rising of the engine rotation pulse of the rotation speed sensor 35.

First, the reference time calculation routine of FIG. 6 will be described. When the processing of this routine is started, CP
In step 100, the U 81 sets, as the pulse time TNINT, the difference between the current time FC at the time of the current NE interrupt obtained by the free running count operation and the interrupt time TO at the time of the previous NE interrupt. In FIG. 9, the value of the pulse counter CNIRQ is "1.
One pulse from "0" to "11" is given as an example, and the time required to advance by the crank angle (11.25 ° CA) corresponding to this one pulse is calculated. Is the pulse time TNINT. Therefore, step 100 constitutes a pulse time calculating means.

Next, the CPU 81 determines in step 110 whether or not the value of the pulse counter CNIRQ is "6". Here, “6” is the predicted pulse time TS1
Of the plurality of pulse signals before the pulse signal having 125a (engine rotation pulse of "8"), it is the value of the calculable engine rotation pulse closest to the engine rotation pulse of "8". If the value of the pulse counter CNIRQ is not "6", the CPU 81 proceeds directly to step 170.

On the other hand, in step 110, the pulse counter C
When the value of NIRQ is "6", the CPU 81 sets the pulse time TNINT previously obtained in step 100 as the instantaneous time TN6 (i) in step 120. As shown in FIG. 9, the instantaneous time TN6 (i) is “11.25 ° C.” in crank angle from when the value of the pulse counter CNIRQ becomes “5” to when it becomes “6”.
This corresponds to the pulse time TNINT required to advance by "A".

Subsequently, in step 130, the CPU 81 reads out the instantaneous time TN6 (i-1) in the previous combustion cycle stored in the previous processing. And the CPU 81
In step 140, the ratio of the instantaneous time TN6 (i) in the present combustion cycle to the instantaneous time TN6 (i-1) in the previous combustion cycle (TN6 (i) / TN6 (i
-1)) is obtained and this is set as the rotation change amount TNRA. Therefore, step 140 constitutes a rotation change amount calculation means.

In this way, in one combustion cycle, the rotation fluctuation of the crankshaft 40 may change according to changes in the engine load, the injection timing, the engine speed NE, etc. This is because the rotational fluctuation of the crankshaft 40 due to the engine load, the injection timing, etc. is slight at the positions corresponding to each of the combustion cycles, and the rotational fluctuation of the previous combustion cycle and the rotational fluctuation of the present combustion cycle are similar. .

In step 150, the CPU 81 calculates the prediction correction coefficient MDT1 according to the rotation change amount TNRA. Therefore, step 150 constitutes rotation change predicted value calculation means. The prediction correction coefficient MDT1 is a coefficient obtained by referring to the map of FIG. 7, and the reference time TS1
To correct 125, the same reference time TS1125 is multiplied. In the map of FIG. 7, when the rotation change amount TNRA is “1”, that is, when the instantaneous time TN6 does not change between the previous combustion cycle and the current combustion cycle, it is not necessary to correct the reference time TS1125. The prediction correction coefficient MDT1 is set to "1". When the rotation change amount TNRA is smaller than "1", that is, when the engine speed NE is increasing, the reference time TS
The prediction correction coefficient MDT1 is set to a value smaller than “1.0” in order to correct 1125 small. When the rotation change amount TNRA is larger than "1", that is, when the engine speed NE is decreasing, the reference time TS1 is set.
The prediction correction coefficient MDT1 is set to a value larger than “1.0” in order to largely correct 125.

In step 160, the CPU 81 prepares for the next calculation, and the instantaneous time TN6 in the present combustion cycle is set.
(I) is the instantaneous time TN6 (i-
1) and store this value. Next, in step 170, the CPU 81 determines whether or not the value of the pulse counter CNIRQ is “9”. Here, if the value of the pulse counter CNIRQ is not "9", the CPU 81 proceeds directly to step 190. On the other hand, when the value of the pulse counter CNIRQ is "9", the CPU 81 determines in step 180 that the pulse time TNI at that time is TNI.
NT is set as the reference time TS1125 and stored.

As shown in FIG. 9, the reference time TS1125 is "11.25" in crank angle from when the value of the pulse counter CNIRQ becomes "8" to when it becomes "9".
This corresponds to the pulse time TNINT required to advance by "° CA".

Further, the reference time TS1125 in FIG.
The position of corresponds to the injection end timing for obtaining the target injection amount determined according to the operating state of the diesel engine 2.

Then, in step 190, the CPU
81 sets the current time FC in step 100 as the previous interrupt time TO, and then ends the subsequent processing. In this way, the reference time TS1125 is calculated.

Next, the spill time TSPON in FIG.
The calculation processing of will be described. When the processing of this routine is started, first in step 201, the CPU 81 determines the engine speed N based on the detection values of the rotation speed sensor 35, the intake pressure sensor 74, and the accelerator opening sensor 73.
E, intake pressure PiM and accelerator opening ACCP are read. Further, the reference time TS1125 and the prediction correction coefficient MDT1 in FIG. 8 are read.

Subsequently, in step 202, the CPU 81 calculates the injection amount command value QFIN as the crank angle during operation from the engine speed NE, the intake pressure PiM and the accelerator opening degree ACCP. Therefore, step 2
Reference numeral 02 constitutes an operating crank angle calculating means. The injection amount command value QFIN is obtained according to a predetermined calculation formula, is represented by a crank angle (° CA), and serves as a spill valve control command value of the present invention.

Then, the CPU 81 calculates the spill timing pulse number CANGL and the surplus angle θREM from the injection amount command value QFIN in step 203. Therefore, step 203 constitutes a surplus angle calculating means. These respective values CANGL, θREM are obtained by referring to the following equation (1).

ΘREM = QFIN-11.25 · CANGL (1) That is, as shown in FIG. 10, the injection amount command value QFIN
Corresponds to the angle of one engine rotation pulse, “11.
25 ”and divide the quotient by the spill time pulse number CAN
It is obtained as GL, and the remainder is obtained as the remainder angle θREM.

Next, in step 204, the CPU 81 corrects the reference time TS1125 with the prediction correction coefficient MDT1 according to the following equation (2). Therefore, step 204 constitutes a predicted pulse time calculating means. The corrected value is the pulse time for one pulse in the vicinity of the target spill timing in the current combustion cycle, and the predicted pulse time T
It is represented by S1125a.

TS1125a = TS1125 · MDT1 (2) Then, in step 205, the CPU 81 calculates the surplus angle θREM previously obtained and the predicted pulse time TS112.
The spill time TSPON is calculated with 5a. Therefore, step 205 constitutes an angle time conversion means. That is, the remainder angle θREM is set to the predicted pulse time TS112.
Time conversion is performed based on 5a. This spill time TSPO
N is calculated according to the following equation (3).

TSPON = (θREM / 11.25) · TS1125a− (TRES + VRR + f (V)) (3) The TRES is a response delay time of the electromagnetic spill valve 23. The response delay time TRES is a value previously obtained by experiments or the like. For example, the operation start timing of the electromagnetic spill valve 23 is set to the lift start timing of the electromagnetic spill valve 23 or the high pressure chamber 1
The response delay time TRES is the difference between the operation start timing and the control signal generation timing, which is detected at the room pressure change timing of 5 or the like.

Therefore, in this embodiment, the above (3)
From the formula and the formula (1), the injection amount command value QFIN is as follows. QFIN = CANGL ・ 11.25+ (TSPON + TRES) ・ 11.25 / TS1125a (4) That is, from the above formula (4), the response delay time TRES of the electromagnetic spill valve 23 is not conventionally considered, so the injection amount command value Although QFIN means the control signal generation timing, in this embodiment, the response delay time TRES
Therefore, the injection amount command value QFIN means the electromagnetic spill valve actual operation timing as the spill valve actual operation timing.

When the surplus angle θREM is converted into time by the processing in step 205, the CPU 81 ends this routine. In step 203, the spill timing pulse number CANGL is obtained, and in step 20
When the spill time TSPON is calculated in 5, the CPU 81
Is an electromagnetic spill valve 2 based on both values CANGL and TSPON.
A control signal for turning off 3 is output. Then, the opening timing of the electromagnetic spill valve 23 adjusts the end timing of the fuel injection from the fuel injection pump 1, that is, the fuel injection amount. (A) By the way, in the present embodiment, the surplus angle θREM is time-converted based on the predicted pulse time TS1125a, and the spill time TSPON is obtained according to the equation (3).

TSPON = (θREM / 11.25) · TS1125a-TRES (3) That is, the spill time TSPON is calculated in consideration of the response delay time TRES of the electromagnetic spill valve 23, and the control response of the electromagnetic spill valve 23 is calculated. Since the rotation change prediction correction is also performed for the delay amount, no error occurs in the fuel injection amount. (B) Further, in the present embodiment, the rotational fluctuation of the crankshaft 40 due to the engine load, the injection timing, etc. is small between the adjacent combustion cycles, and the rotational fluctuation of the previous combustion cycle and the rotational fluctuation of the present combustion cycle are small. Utilizes the phenomenon that and are similar. The time required for a predetermined engine rotation pulse by the rotation speed sensor 35 is calculated as the pulse time TNINT (step 100). When calculating the valve opening timing of the electromagnetic spill valve 23 in the current combustion cycle, the pulse time (instantaneous time TN6) of the predetermined pulse signal in the previous combustion cycle is calculated.
(I-1)) and the pulse time (instantaneous time TN6 (i)) of the pulse signal corresponding to the predetermined pulse signal in the current combustion cycle, the change amount between them (rotation change amount TN).
RA) is calculated (step 140), and the rotation change amount of the crankshaft 40 is predicted based on the change amount.

Therefore, even if the calculated amount of change in rotation of the crankshaft 40 (predicted value of change in rotation) is not corrected according to changes in the engine load, the injection timing, and the engine speed NE, the diesel engine 2 can be operated with high accuracy. It is possible to predict the rotation change of the. (C) In the present embodiment, the crank angle (injection amount command value QFIN) when the electromagnetic spill valve 23 is opened is calculated in order to obtain the target fuel injection amount according to the operating state of the diesel engine 2. (Step 202). In the operating pulse signal (engine rotation pulse of "8") including the injection amount command value QFIN, a surplus angle θREM that is less than one pulse from the rise of the engine rotation pulse to the injection amount command value QFIN is calculated (step 203). From the required time (reference time TS1125) of the pulse signal (engine rotation pulse of "8") and the crankshaft 40 rotation change amount TNRA in the previous combustion cycle corresponding to the operating pulse signal, the required time of the operating pulse signal The predicted pulse time TS1125a is calculated (step 20)
4). A unit angle (11.25 ° CA) that is an interval between engine rotation pulses, and the predicted pulse time TS1
Using 125a, the spill time TSPON is calculated by converting the surplus angle θREM into time (step 205).

Therefore, since the highly accurate rotation change amount TNRA of the crankshaft 40 is used as described above, the surplus angle θREM required for calculating the valve opening timing of the electromagnetic spill valve 23 can be accurately converted into time.

Next, the second embodiment will be described focusing on the points different from the first embodiment. As shown in FIG. 13, the CPU 81 is adapted to detect the voltage V of a vehicle-mounted battery (not shown) via the buffer 103, the multiplexer 92, the A / D converter 93, and the input port 85. In this embodiment, the CPU 81 is different from the spill time calculating routine shown in FIG.

TSPON = (θREM / 11.25) · TS1125a- (TRES + VRR + f (V)) (5) The VRR is a variation correction term of the electromagnetic spill valve 23, and corresponds to the opening time of the electromagnetic spill valve 23. It is provided in order to eliminate the influence of the difference between individuals, and this term is obtained in advance by experiments or the like and stored in the ROM 82. Then, this correction term is read in step 205. or,
f (V) is a correction term for the vehicle battery voltage. This voltage correction term f (V) is calculated by the CPU 81 in step 205 based on the battery voltage V or calculated from a map. The map is stored in the ROM 82 in advance.

The map shows that the higher the battery voltage,
That is, the higher the control voltage of the electromagnetic spill valve 23, the worse the response of the electromagnetic spill valve 23. Therefore, the higher the control voltage, the larger the correction amount corresponding to the amount of change in the response to the control voltage. Has been done. The change amount of the responsiveness is the amount (time) of how much the response time changes with respect to the control voltage at a predetermined reference voltage when the control voltage changes.

Further, the variation correction term of the electromagnetic spill valve 23 is the variation amount (time) of how much the control response varies with respect to the control response of the standard electromagnetic spill valve, and is the individual electromagnetic spill. This is the eigenvalue of the valve.

Therefore, in this embodiment, not only the response delay time TRES of the electromagnetic spill valve 23 but also the correction term for eliminating the variation among the individual electromagnetic spill valves 23 and the control voltage correction term for the electromagnetic spill valve 23. The spill time TSPON is calculated in consideration of the above, and since the control response delay amount of the electromagnetic spill valve 23, the variation between the individual electromagnetic spill valves 23, and the control voltage are also corrected for rotation change prediction,
There is no more error in the fuel injection amount than in the above embodiment.

The present invention is not limited to the above-mentioned embodiment, and a part of the configuration can be appropriately modified within the scope not departing from the gist of the present invention and carried out as follows.

(A) In both of the above embodiments, the number of protrusions of the pulsar 7 is set so that the rotation speed sensor 35 outputs the engine rotation pulse number every 11.25 ° CA. However, the present invention is not limited to this. Instead, the number of protrusions of the pulsar 7 may be changed.

(B) In both of the above embodiments, the response delay time TRES is taken into consideration when the electromagnetic spill valve 23 is opened, but the response delay time TRESO is taken into consideration when the electromagnetic spill valve 23 is closed. May be.

For example, when the number of protrusions of the pulsar 7 is the same as in the first embodiment, and the valve closing command time for driving the valve closing is TPS, the valve closing command timing Qps is as follows. .

Qps = CANGps-11.25 + (TPS + TRE
S0) · 11.25 / TS1125a Note that the CANGps is the valve closing command timing pulse number. Therefore, the valve closing command timing TPS is given by the following formula.

TPS = (Qps−CANGps · 11.25) /11.25−TRES0 (C) In the first embodiment, the instantaneous time in the current combustion cycle is different from the instantaneous time TN6 (i−1) in the previous combustion cycle. Ratio of TN6 (i) (TN6 (i) / TN
6 (i-1)) was obtained and was used as the rotation change amount TNRA. The deviation (TN6 (i) -TN6) between the two instantaneous times was calculated.
(I-1)) may be obtained and used as the rotation change amount. (D) In the above embodiment, the diesel engine 2 including the turbocharger 48 as a supercharger is embodied, but a diesel engine including a supercharger as a supercharger or a supercharger is not provided. It can be embodied in a diesel engine or even a gasoline engine.

(E) In the second embodiment, both the control voltage of the on-vehicle battery and the response delay due to the variation among the electromagnetic spill valves 23 are taken into consideration. However, the on-vehicle battery or the electromagnetic spill valve is used. Of the response delay time TRE in the first embodiment
It may be added to S or may be added to the response delay time TRESO when the electromagnetic spill valve is closed.

The technical ideas other than the claims understood from the above-described embodiment will be described below together with their effects. (1) In claim 2, an engine rotation angle detecting means for detecting a rotation angle of the engine by generating a pulse signal for each predetermined unit angle with the rotation of the engine, and a predetermined pulse signal by the engine rotation angle detecting means. And a pulse time calculating means for calculating the required time as a pulse time, the control means calculates a spill valve control command value as a spill valve actual operation time based on the engine operating state, and the spill valve control is performed in the past. Change amount between the pulse time of the predetermined pulse signal calculated by the predetermined pulse time calculating means in the combustion cycle and the pulse time of the pulse signal corresponding to the predetermined pulse signal in the present combustion cycle, and the change amount Injection timing control device for an internal combustion engine that predicts changes based on engine speed based on the engine speed.

For example, when the pulse time of the predetermined pulse signal is calculated by the predetermined pulse time calculating means in the previous combustion cycle as the past combustion cycle, the engine load (engine load), the injection timing, etc., between the adjacent combustion cycles, Is small, and the rotation fluctuation of the previous combustion cycle and the rotation fluctuation of this combustion cycle are similar. By utilizing this phenomenon, when calculating the opening / closing control timing of the spill valve, the rotation change amount of the engine rotation can be calculated from the pulse time of the predetermined pulse signal in the previous combustion cycle and the pulse time corresponding to the predetermined pulse signal in the current combustion cycle. It can be easily predicted. As a result, the rotational change prediction can be performed with high accuracy without correcting the rotational change amount of the engine according to the engine load, the injection timing, and the change of the engine speed. (2) In the above (1), the operating state detecting means for detecting the operating state of the internal combustion engine and the actuator are operated to obtain the target fuel injection amount of the internal combustion engine according to the operating state by the operating state detecting means. In the operation pulse signal including the operation crank angle calculating means for calculating the actual crank angle as the operation crank angle and the operation pulse signal including the operation crank angle by the operation crank angle calculating means, A surplus angle calculation means for calculating a surplus angle that is less than one pulse up to the crank angle during operation, and a pulse signal in the previous combustion cycle calculated by the pulse time calculation means and corresponding to the operation pulse signal. Based on the required time and the rotation change prediction value of the crankshaft calculated by the rotation change prediction value calculation means, the operating pulse By using a prediction pulse time calculation means for calculating a prediction pulse time that is a required time of the signal, a unit angle that is the generation interval of the pulse signal, and a prediction pulse time calculated by the prediction pulse time calculation means. A fuel injection timing control device for an internal combustion engine, comprising: angle-time conversion means for converting a surplus angle into time. By providing these means, the control response delay amount of the spill valve is also predicted and corrected for rotation change, and an error does not occur in the fuel injection amount. (3) The spill valve is an electromagnetic spill valve, and the control means corrects the responsiveness change amount caused by the control voltage of the electromagnetic spill valve when controlling the opening and closing of the spill valve. ), The fuel injection timing control device for an internal combustion engine according to any one of (2). With this configuration, it is possible to deal with a change in response due to the control voltage of the electromagnetic spill valve, and the fuel injection accuracy is improved. (4) The spill valve is an electromagnetic spill valve, and the control means corrects the amount of variation in responsiveness among individual electromagnetic spill valves when controlling the opening and closing of the spill valve. , (2), or (3), the fuel injection timing control device for an internal combustion engine. With this configuration, it is possible to deal with the variation amount of the response characteristic of the standard electromagnetic spill valve with respect to the standard electromagnetic spill valve, and the fuel injection accuracy is improved.

[0081]

As described above in detail, according to the invention of claim 1, the spill valve control response delay amount also elapses even in a case other than the specific operating state such as when the engine speed suddenly changes. Since the correction is performed according to the rotation angle, there is an effect that an error does not occur in the fuel injection amount.

Further, in addition to the effect of claim 1, the invention of claim 2 rotates the spill valve control response delay by the amount other than the specific operation state such as when the engine speed suddenly changes. Because the change prediction is corrected, there is no difference in the fuel injection amount,

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a diesel engine, a fuel injection pump, a rotation change prediction device, and a crank angle time conversion device according to a first embodiment.

FIG. 2 is an enlarged sectional view of the fuel injection pump.

FIG. 3 is a front view of a pulsar and a rotation speed sensor.

FIG. 4 is an explanatory view showing an output waveform of an engine rotation pulse similarly by a rotation speed sensor.

FIG. 5 is a block diagram showing the electrical configuration of the ECU.

FIG. 6 is a flowchart similarly illustrating a reference time calculation routine.

FIG. 7 is a characteristic diagram showing a map that similarly defines the relationship between the amount of change in rotation and the prediction correction coefficient.

FIG. 8 is a flowchart illustrating a spill time calculation routine that is also executed by the CPU.

FIG. 9 is an explanatory view showing a correspondence relationship between fluctuations in engine speed and engine rotation pulses.

FIG. 10 is an explanatory view showing a corresponding relationship between engine rotation pulses and operation of an electromagnetic spill valve.

FIG. 11 is a characteristic diagram showing the correlation between the rotation change amount between two combustion cycles and the ratio of the predicted pulse time to the reference time.

FIG. 12 is a characteristic diagram showing the correlation between the rotation change amount obtained in the current combustion cycle and the ratio of the predicted pulse time to the reference time, for comparison with FIG. 11.

FIG. 13 is a block diagram showing an electrical configuration of an ECU according to a second embodiment.

[Explanation of symbols]

2 ... Diesel engine (internal combustion engine), 23 ... Electromagnetic spill valve, 35 ... Rotation speed sensor (crank angle detecting means and operating state detecting means), 40 ... Crankshaft, 73 ... Accelerator opening sensor (operating state detecting means), 81 ... CPU (control means, pulse time calculation means, rotation change predicted value calculation means,
Operating crank angle calculating means, surplus angle calculating means, angle time converting means, and predicted pulse time calculating means), ACCP
... accelerator opening (operating state of internal combustion engine), NE ... engine speed (operating state of internal combustion engine, crankshaft speed per unit time), TNINT ... pulse time, TN
RA ... Rotation change amount, TS1125 ... Reference time (time required for pulse signal in previous combustion cycle corresponding to operating pulse signal), TS1125a ... Predicted pulse time, QFI
N ... Injection amount command value (operating crank angle), θREM ...
Surplus angle, TSPON ... Spill time (time conversion value of surplus angle)

Claims (2)

[Claims] 1. A plunger pump having a plunger that pressurizes fuel, a spill valve that opens and closes a fuel relief passage that connects a pump chamber of the plunger pump and a low-pressure side, and control means that controls the opening and closing of the spill valve. In a fuel injection timing control device for an internal combustion engine comprising: the control means, when controlling the opening and closing of the spill valve, corrects the spill valve response delay that is variable according to the engine speed of the internal combustion engine. A characteristic fuel injection timing control device for an internal combustion engine. 2. The control means calculates a spill valve control command value as a spill valve actual operation timing based on an engine operating state in the combustion cycle, and controls the spill valve based on the spill valve control command value. The spill valve response delay is corrected and executed for an angle-time conversion value from a predetermined engine rotation angular position that has been subjected to prediction correction based on engine rotation in a past combustion cycle. Fuel injection timing control device for internal combustion engine.