JPH0526088A - Engine crank angle detection method - Google Patents

Abstract

PURPOSE:To conduct high precision crank angle detection while shift with the time change of an actual crank angle is being compensated. CONSTITUTION:In a case in which a predetermined crank angle in the vicinity of the fuel injection 4 time of a diesel engine 2 is detected 76, when a redundant angle thetaREMa between an engine revolution pulse rise-up obtained at every fixed crank angle and the next rise-up is detected and the time conversion of the same angle thetaREMa is made, the nearer the redundant angle thetaREMa is to a middle position between the rise-up and the next rise-up of the engine revolution pulse interposing the same angle thetaREMa, the larger the correction amount is made, and the final redundant angle thetaREM is decided. In addition, the time conversion of the final redundant angle thetaREM is made on the basis of a certain angle time. Accordingly, the redundant angle thetaREMa is corrected in conformity with the curvilinear change of an actual crank angle, and the final redundant angle thetaREM that has compensated shift with the time change of the actual crank angle, is obtained, and a high precision time conversion is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crank angle detecting method for detecting a crank angle used for arithmetic processing of fuel injection amount control in an engine applied to an automobile, for example.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection pump for an electronically controlled diesel engine, for example, an electromagnetic spill valve or the like is controlled so that a spill port is controlled so that a fuel injection amount obtained according to the lift of the plunger reaches a target value. I am trying to open it. This causes the fuel from the high pressure chamber of the plunger to overflow (spill) into the fuel chamber, and the pressure feeding of the fuel ends,
That is, the end of fuel injection is controlled to control the required fuel injection amount.

In such an electromagnetic spill valve, the target spill angle is usually converted into time by a signal which is synchronized with the lift of the plunger and is input at a constant pump rotation angle, for example, an engine rotation pulse and an average engine rotation speed. The target spill timing is determined based on the target spill timing, and the electromagnetic spill valve is controlled on / off based on the target spill timing.

For example, in the "injection amount control method for an electronically controlled diesel engine" disclosed in Japanese Patent Application Laid-Open No. 61-234252, engine rotation obtained at a constant crank angle in order to obtain a required fuel injection amount. Based on the pulse, the pulse count number from a certain reference position of the engine rotation pulse to the target spill angle and the surplus angle that is less than one pulse are obtained, and the surplus angle is converted to time based on the engine speed, and the target spill timing I am trying to decide. In this case, the engine rotation time is predicted based on the instantaneous rotation speed between the predetermined crank angles including the target spill angle this time, and the surplus angle is converted to time based on the predicted rotation time. I have to.

[0005]

However, in the technique of the above-mentioned conventional publication, the change in the instantaneous rotational speed of the diesel engine is treated as being constant during a predetermined crank angle, unlike the actual change. .. That is, as shown in FIG. 13, the temporal change of the instantaneous rotation speed of the diesel engine is not actually constant, and a rotation fluctuation having a certain cycle occurs even within one rotation. Here, in this temporal change in the instantaneous rotation speed, as shown in FIG. 14, a predetermined crank angle corresponds to "11.25 °" corresponding to one pulse from one rising of the engine rotation pulse to the next rising.
In the case of “CA”, the actual time change of the crank angle during one pulse becomes a curve corresponding to the time change of the instantaneous rotation speed. On the other hand, in the technique of the above publication, the time change of the instantaneous rotation speed is treated as being constant during the predetermined crank angle, and therefore the time change during one pulse is shown by the solid line in FIG. It will be treated as a straight line complement as shown in.

Therefore, the remaining angle to be time-converted this time is "11.25 ° C", which corresponds to, for example, one pulse.
In the case of “5.625 ° CA” located in the middle of “A”, if the predicted time of “11.25 ° CA” is “3 ms”, the result of time conversion of the surplus angle is “1.5 ms”. Becomes However, since the actual time change of the crank angle changes in a curve, there is a deviation from the change of the crank angle, and the deviation is "11.25 °".
It increases as it approaches the intermediate position of "CA". Further, the deviation becomes larger as the temporal change of the instantaneous rotation speed becomes larger. As a result, it was not possible to accurately perform time conversion of the angle due to the deviation.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to determine the actual crank angle between the rising of the engine rotation pulse obtained for each predetermined crank angle and the next rising. It is an object of the present invention to provide a crank angle detecting method for an engine, which is capable of detecting a crank angle with high accuracy while compensating for a deviation with time.

[0008]

In order to achieve the above object, according to the present invention, in a crank angle detecting method for detecting a predetermined crank angle in the vicinity of the time when the instantaneous rotation speed of the engine is minimum, a constant crank angle is detected. The crank angle from the rising of the engine rotation pulse obtained for each angle to the next rising is detected, and based on the angular time required to rotate the same angle at the previous same crank angle position, the detection target and When converting between the crank angle and time, the closer the crank angle that is the detection target is to the intermediate position between the rising of the engine rotation pulse that sandwiches the crank angle and the next rising, The correction amount is increased.

[0009]

[Function] The crank angle from the rising of the engine rotation pulse obtained for each predetermined crank angle to the next rising is detected in the vicinity of the time when the engine instantaneous rotation speed becomes the lowest, and the crank angle is set to the same crank angle position of the previous time. Based on the angle time required to rotate by the same angle, when converting between the crank angle that is the detection target and the time,
The time change of the crank angle between engine rotation pulses is
Contrary to the curvilinear time change of the actual crank angle, the linear interpolation is performed.

Therefore, according to the above configuration, as the crank angle to be detected is closer to the intermediate position between the rising of the engine rotation pulse sandwiching the crank angle and the next rising, the correction amount of the crank angle is increased. Becomes larger, the crank angle is corrected in conformity with the curvilinear change of the actual crank angle.

[0011]

【Example】

(First Embodiment) A first embodiment of the method for detecting the crank angle of an engine according to the present invention is applied to a diesel engine.
An embodiment will be described in detail with reference to FIGS.

FIG. 8 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine with a supercharger in this embodiment, and FIG. 9 is a sectional view showing the distribution type fuel injection pump 1. The fuel injection pump 1 includes a drive pulley 3 drivingly connected to a crankshaft 40 of a 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 each fuel injection nozzle 4 provided for each cylinder (four cylinders in this case) of the diesel engine 2 to perform fuel injection. ..

In the fuel injection pump 1, the drive pulley 3 is attached to the tip of the drive shaft 5.
Further, a fuel feed pump (developed by 90 degrees in this figure) 6 which is 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 diesel engine 2 is attached to the outer peripheral surface of the pulsar 7.
The same number as the number of cylinders, that is, in this case, four cutting teeth are formed at equal angular intervals, and 14 projections (56 in total) are formed at equal angular intervals between each cutting tooth. There is. 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. There is. Cam face 8
The number a is 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, when the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via the coupling, the cam plate 8 is engaged with the cam roller 10 while rotating, and reciprocates in the left-right direction in the figure by the same number as the number of cylinders. Driven. In addition, the plunger 12 is reciprocally driven in the same direction while rotating with the reciprocating motion. That is,
When the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, the plunger 12 is moved forward (lifted), and conversely, when the cam face 8a rides on the cam roller 10, the plunger 12 is moved back.

The plunger 12 is fitted into 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 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. Also, those suction grooves 16
And the pump housing 13 corresponding to the distribution port 17.
A distribution passage 18 and a suction port 19 are formed therein.

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 suction stroke in which the plunger 12 is returned and the high pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 into the high-pressure chamber 15 by communicating one of the six with the suction port 19. 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 4 of each cylinder.

A spill passage 22 for fuel overflow (spill) is formed in the pump housing 13 to connect the high pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 as a spill adjusting valve for adjusting the 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, and the valve body 25 is opened to spill the fuel in the high pressure chamber 15 to the fuel chamber 21 when the coil 24 is not energized (OFF). 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 amount of fuel from the high pressure chamber 15 to the fuel chamber 21 is controlled. 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, the amount of fuel injection from the fuel injection nozzle 4 is controlled by controlling the closing / opening timing of the electromagnetic spill valve 23 during the forward movement of the plunger 12.

Below the pump housing 13, a timer device (developed by 90 degrees in this figure) 26 for adjusting the fuel injection timing 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 hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a timer in a low pressure chamber 29 on one side of the timer housing 27. It is composed of a timer spring 31 and the like for urging the piston 28 against the pressurizing 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, the position of the roller ring 9 is determined by determining the position of the timer piston 28, and the position of the roller 1 is determined via the cam plate 8.
The reciprocating timing of 2 is determined.

In order to adjust the fuel pressure of the timer device 26, that is, the control oil pressure, 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 communicate with each other through the communication passage 34.
The timing control valve 33 is provided in the middle of the communication passage 34. The timing control valve 33 is an electromagnetic valve whose opening and closing is controlled by a duty-controlled energizing signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening and closing control of the timing control valve 33. Then, by adjusting the fuel pressure, the lift timing of the plunger 12 is controlled, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

On the upper part of the roller ring 9, a rotation speed sensor 35 composed of an electromagnetic pickup coil is attached so as to face the outer peripheral surface of the pulsar 7. This rotation speed sensor 35
Is a timing signal corresponding to the engine speed NE when the protrusions of the pulsar 7 cross each other, and an engine rotation pulse as a rotation angle signal for each predetermined crank angle (11.25 ° CA). Is output. Further, since this rotation speed sensor 35 is integrated with the roller ring 9, it outputs a reference timing 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 main combustion chamber 44 corresponding to each cylinder is formed by the cylinder 41, the piston 42, and the cylinder head 43. or,
Each of the main combustion chambers 44 is connected to a sub-combustion chamber 45 that is also provided corresponding to each cylinder. Then, the fuel injected from each fuel injection nozzle 4 is supplied to each auxiliary combustion chamber 45. 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, the intake pipe 47 is provided with a copressor 49 of a turbocharger 48 constituting a supercharger, and the exhaust pipe 50 is provided with a turbocharger. 48
The turbine 51 is provided. Further, the exhaust pipe 50 is provided with a waste gate valve 52 for adjusting the supercharging pressure PiM. As is well known, this turbocharger 48 uses the energy of exhaust gas to rotate a turbine 51, and a compressor 49 located coaxially therewith.
Is rotated to increase the pressure of the intake air. As a result, a dense air-fuel mixture is sent to the main combustion chamber 44 to burn a large amount of fuel, and the output of the diesel engine 2 is increased.

Further, the diesel engine 2 has an exhaust pipe 5
A recirculation pipe 54 is provided for recirculating a part of the exhaust gas in 0 to the intake port 53 of the intake pipe 47. An exhaust gas recirculation valve (EGR valve) 55 for adjusting the amount of exhaust gas recirculation is provided in the middle of the recirculation pipe 54. The EGR valve 55 is controlled to open / close under the control of 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. Also, the throttle valve 5
A bypass passage 59 is provided in parallel with 8, 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 a smooth stop.

Then, the electromagnetic spill valve 2 provided in 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, and the drive timings thereof are controlled by the ECU 71.

As a sensor for detecting the operating state, the following various sensors are provided in addition to the rotation speed sensor 35. That is, the intake pipe 47 is provided with an intake air temperature sensor 72 for detecting the intake air temperature THA near the air cleaner 64. 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. An intake pressure sensor 74 for detecting 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. Further, a crank angle sensor 76 is provided for detecting a rotation reference position of the crankshaft 40 of the diesel engine 2, for example, a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder. 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.

The above-mentioned sensors 72 to 77 are respectively connected to the ECU 71, and the rotation speed sensor 3 is connected.
5 is connected. Further, the ECU 71 uses the sensors 35,
Based on the signals output from 72 to 77, the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSVs 56, 61, 62 and the like are suitably controlled.

Next, the structure of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. ECU 71
Is a central processing unit (CPU) 81, a read-only memory (RO
M) 82, a random access memory (RAM) 83 for temporarily storing calculation results of the CPU 81, a backup RAM 84 for storing prestored data, and the like, and a bus 87 for connecting these units, an input port 85, an output port 86, and the like.
It is configured as a logical operation circuit connected by.

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 and 9, respectively.
1, the multiplexer 93, and the A / D converter 94. Similarly, the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above are connected to the input port 85 via a waveform shaping circuit 95. Then, the CPU 81 reads the detection signals of the sensors 35, 72 to 77, etc., which are input via the input port 85, as input values. Further, each drive circuit 9 is connected to the output port 86.
The electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62 and the like are connected via 6, 97, 98, 99, 100, 101.

Then, the CPU 81 controls the sensors 35 and 72.
Electromagnetic spill valve 2 based on input values read from ~ 77
3, the timing control valve 33, the glow plug 46, the VSV 56, 61, 62, etc. are suitably controlled.

Next, the processing operation of the crank angle detection and the processing operation of the fuel injection amount control executed by the aforementioned ECU 71 will be described with reference to FIGS. The flowchart shown in FIG. 1 is a main routine for controlling the fuel injection amount in the fuel injection pump 1 among the respective processes executed by the ECU 71, and is executed by a regular interrupt every predetermined time.

When the processing shifts to this routine, first, at step 101, the engine speed NE, the accelerator opening ACCP and the cooling water temperature are based on the detected values of the rotation speed sensor 35, the accelerator opening sensor 73 and the water temperature sensor 75. Read THW respectively.

Then, in step 102, the corrected accelerator opening ACCPA is calculated from the accelerator opening ACCP and the cooling water temperature THW. The corrected accelerator opening degree ACCPA is a pseudo accelerator opening degree ACSTA at the time of start, which is obtained according to the cooling water temperature THW, and the accelerator opening degree A.
Calculated by comparison with CCP.

Next, at step 103, the engine speed NE previously read and the corrected accelerator opening A
The final injection amount QFIN is calculated based on CCPA and the like. This final injection amount QFIN is obtained according to the following calculation formula (1). Incidentally, “C1, C2, C3” in the equation are constants.

QFIN = C1 + C2 × ACCPA × C3 × NE (1) Then, in step 104, the spill timing pulse number CANG is calculated based on the final injection amount QFIN previously obtained.
La and the remainder angle θREMa are calculated respectively. These spill timing pulse number CANGLa and surplus angle θRE
Ma is calculated with reference to the following calculation formula (2).

QFIN = 11.25 × CANGLa + θREMa (2) That is, as shown in FIG. 2, the final injection amount QFIN is “11.25” corresponding to the angle of one engine rotation pulse.
Divide by and divide the quotient by the number of pulses in the spill period CANGLa
And the remainder is determined and set as the remainder angle θREMa. Where spill time pulse number CA
NGLa uses an electromagnetic spill valve 23 to terminate fuel injection.
Corresponds to the engine rotation pulse number corresponding to the spill timing at which the fuel should be turned off, that is, the fuel should be spilled (in FIG. 2, it is "9"). Further, the surplus angle θREMa is a value indicating a more strict spill timing in terms of the spill timing pulse number CANGLa.

Next, at step 105, the theoretical theoretical spill-time pulse time TS1125A is calculated based on the engine speed NE previously read. This theoretical spill-time pulse time TS1125A is "11.25
This is the time required to advance by a crank angle of "° CA", which is a value converted from the magnitude of the engine speed NE.

Then, in step 106, the ratio of the pulse time TS1125 during spill and the theoretical pulse time TS1125A during spill calculated in the previous step 105 is calculated, and the calculated result is set as the pulse time ratio α. .. This pulse time ratio α is the actual engine speed N
In the change of E, the change becomes the smallest near the instantaneous maximum rotation speed, and the instantaneous minimum rotation speed (TDC, BDC)
The change is greatest near. This pulse time ratio α
Indicates that the smaller the value, the smaller the fluctuation of the engine speed NE, and the larger the value, the larger the fluctuation of the engine speed NE.

Here, the pulse time during spill TS1125
Is the number of spill timing pulses in the previous control cycle CANGL
This corresponds to one pulse time TNINT in a and is obtained according to a separate flowchart shown in FIG. This flowchart is an NE interrupt routine, which is executed by an interrupt for each pulse input of the engine speed NE. That is, in step 210, one pulse time TNINT corresponding to the spill timing pulse number CANGLa in the previous control cycle is calculated. Then, in step 220, the pulse time TNIN
T is set as the spill time pulse time TS1125, and the subsequent processing is once ended.

Returning to the main routine of FIG. 1 again, in step 107, the surplus angle θREM previously obtained is obtained.
The final remainder angle θREM is calculated from a and the pulse time ratio α. That is, the residual angle θREMa is corrected to obtain the final residual angle θREM. This calculation is obtained by referring to the following calculation formula (3).

ΘREM = (5.625− | 5.625−θREMa |) × α × C + θREMa (3) That is, in this calculation formula, as shown in FIG. 4, the residual angle θREMa to be detected is As the engine rotation pulse that sandwiches the surplus angle θREMa approaches an intermediate position between the rising and the next rising, the surplus angle θR
The correction amount of EMa is largely corrected. That is, as shown in FIG. 5, the residual angle θREMa is “5.62” corresponding to half of “11.25 ° CA” for one pulse.
It is set such that the correction amount of the surplus angle θREMa increases as it approaches “5 ° CA”. In the above calculation formula (3), “C” is a constant.

Then, in step 108, the spill timing pulse number CANGL is determined based on the final remainder angle θREM and the spill time pulse time TS1125 previously obtained.
Calculate the spill time TSPONa at a. That is,
The final remainder angle θREM is converted into time. The spill time TSPONa is calculated according to the following calculation formula (4).

TSPONa = (θREM / 11.25) × TS1125 (4) After that, in step 109, the spill time TSPONa is set to a predetermined value in order to prevent the delay due to the multiple interruption in consideration of the processing speed of the ECU 71. 100μ
It is determined whether it is smaller than "s". Here, when the spill time TSPONa is smaller than the predetermined “100 μs”, in step 110, as shown in FIG.
Pulse time T at spill after correction to spill time TSPONa
The result of adding S1125A is the final spill time TSPO
Set as N. In step 113, the result obtained by subtracting "1" from the spill timing pulse number CANGLa is set as the final spill timing pulse number CANGL.

Then, in step 111, the electromagnetic spill valve 23 is turned off based on the set final spill timing pulse number CANGL and final spill time TSPON, and the end timing of fuel injection from the fuel injection pump 1, that is, the fuel injection amount. Control, and the subsequent processing is once ended.

On the other hand, when the spill time TSPONa is equal to or longer than the predetermined “100 μs” in step 109, in step 112, the spill time TSPONa is directly changed to the final spill time TSP as shown in FIG.
Set as ON. Further, in the same step 112,
The spill timing pulse number CANGLa is set as it is as the final spill timing pulse number CANGL.

Then, in step 111, the electromagnetic spill valve 23 is turned off based on the set final spill timing pulse number CANGL and final spill time TSPON, and the end timing of fuel injection from the fuel injection pump 1 is reached.
That is, the fuel injection amount is controlled, and the subsequent processing is once ended.

The fuel injection amount control in the diesel engine 2 is executed as described above. In this embodiment, as the crank angle corresponding to the surplus angle θREMa to be time-converted in the fuel injection amount control approaches the intermediate position between the rising edges of the two engine rotation pulses that sandwich the same angle, the actual crank angle is increased. The deviation from the change in angle increases. That is, since the temporal change in the instantaneous rotation speed is treated as being constant during the predetermined crank angle, the temporal change in the crank angle for one pulse used in the calculation of the surplus angle θREMa is shown in FIG. The line is complemented as shown by the solid line. In contrast,
The actual change of the crank angle with time is curved as shown by the broken line in FIG. 4, and the closer to the intermediate position of the crank angle for one pulse, the linearly supplemented crank angle corresponding to the surplus angle θREMa. There will be a large gap between the changes.

Therefore, in this embodiment, the crank angle corresponding to the linearly complemented surplus angle θREMa is "5. 5" at the intermediate position between the rising edges of the two engine rotation pulses sandwiching the crank angle. 62
The closer to 5 ° CA ”, the larger the correction amount is, and the final remainder angle θREM is determined.

Therefore, the crank angle is corrected in conformity with the curvilinear change of the actual crank angle, and the final remainder angle θREM that compensates for the deviation from the actual time change of the crank angle is determined, which is higher. Accurate final remainder angle θRE
M can be obtained. As a result, the final remainder angle θR
The time conversion of EM can be performed with higher accuracy.

Further, when the final remainder angle θREM obtained with higher accuracy is the same angle at the previous same crank angle position, that is, the angle time required to rotate by "11.25 ° CA", the spill is required. Since the time conversion is performed based on the pulse time TS1125, the fuel spill timing can be determined more accurately, and the fuel injection amount control can be performed with high accuracy.

(Second Embodiment) Next, a second embodiment in which the engine crank angle detecting method according to the present invention is embodied in a diesel engine will be described with reference to FIGS. 11 and 12. In this embodiment, the basic structure of the diesel engine is the same as that of the first embodiment, and the description thereof will be omitted. Only the difference regarding the processing operation of the crank angle detection executed by the ECU 71 will be described.

The flowchart shown in FIG. 11 is executed by the ECU 71.
2 shows a part of a processing routine executed by a timed interrupt for controlling the fuel injection timing by the fuel injection pump 1 among the respective processing executed by.

In this routine, in step 310, the engine speed N is determined based on the value detected by the speed sensor 35.
Read E. Next, at step 311, a theoretical theoretical spill-time pulse time TS1125A is calculated based on the read engine speed NE.

Then, in step 312, the ratio of the spill time pulse time TS1125 and the theoretical spill time pulse time TS1125A obtained in the previous step 311 is calculated, and the calculated result is set as the pulse time ratio α.

Here, the pulse time during spill TS1125
Is the number of spill timing pulses in the previous control cycle CANGL
It corresponds to one pulse time TNINT in a and is obtained according to a separate flowchart not shown.

Further, in step 313, the reference angle θ1 is calculated from the reference time T and the spill pulse time TS1125. This calculation is obtained by referring to the following calculation formula (5).

Θ1 = (T / TS1125) × 11.25 (5) Here, the reference time T is a value obtained according to a separate flowchart not shown. That is, as shown in FIG. 12, the reference time T is a time calculated from the engine rotation pulse obtained by the detection of the rotation speed sensor 35 and the reference position signal obtained by the detection of the crank angle sensor 76. It corresponds to the time between the rising edge of the signal and the immediately preceding rising edge of the engine rotation pulse. As is clear from the calculation formula (5), the reference angle θ1 is the spill pulse time TS112 corresponding to the crank angle corresponding to “11.25 ° CA” in the reference time T.
It is a value obtained by converting the angle by 5.

Subsequently, in step 314, the corrected reference angle θ2 is obtained from the previously obtained reference angle θ1 and the pulse time ratio α. That is, the reference angle θ1 is corrected to obtain an angle approximate to the actual crank angle. The corrected reference angle θ2 is calculated according to the following calculation formula (6).

Θ2 = θ1− (θ1−5.625) × α × C (6) That is, in this calculation formula, as shown in FIG. 12, the reference angle θ1 to be the detection target is sandwiched by the reference angle θ1. As the engine rotation pulse approaches an intermediate position between one rising edge and the next rising edge, the correction amount of the reference angle θ1 is increased. That is, the reference angle θ1 is “5.625, which corresponds to half of“ 11.25 ° CA ”for one pulse.
The correction amount of the reference angle θ1 is set to increase as it approaches “° CA”. In the calculation formula (6), “C” is a constant.

In this way, the reference angle θ1 is corrected, and the corrected reference angle θ2 adapted to the time change of the actual crank angle is obtained. The corrected reference angle θ2 is
It is used for timing control of the timer device 26 of the fuel injection pump 1.

Therefore, also in this embodiment, the crank angle is corrected in conformity with the curvilinear change of the actual crank angle, and the corrected reference angle is compensated for the deviation from the actual time change of the crank angle. Since θ2 is determined, the corrected reference angle θ2 can be obtained with higher accuracy. In addition, the corrected reference angle θ2 obtained with higher accuracy is set to the timer device 2
6 is used for timing control, the fuel spill timing can be determined more accurately, and fuel injection timing control can be performed with high accuracy.

The present invention is not limited to the above-described embodiments, but may be implemented by appropriately modifying a part of the configuration without departing from the spirit of the invention. (1) In the first embodiment, in order to correct the surplus angle θREMa, the final surplus angle θREM is determined with reference to the calculation formula (3) represented by a linear function.
The remainder angle θR with reference to the calculation formula (7) represented by the following function
The final remainder angle θREM may be determined by correcting EMa.

ΘREM = (θ0 / 2) ² − (θREMa−θ0 / 2) ² × α × C + θREMa (7) (2) In the first embodiment, near the time when the instantaneous rotation speed drops to the minimum. Although the method for detecting the predetermined crank angle of 1 has been described, the method may be applied to the time when the rising is started from the time when the instantaneous rotation speed becomes the lowest. In this case,
Calculation formulas (3), (6) in the description of the first embodiment,
It is clear that the sign (±) of the correction term (correction amount) in (7) may be reversed.

(3) In each of the above-described embodiments, the fuel injection amount control or the fuel injection timing control of the diesel engine 2 is embodied and explained. However, for example, when detecting the crank angle near the target ignition timing of the gasoline engine, It can also be applied and embodied.

[0069]

As described above in detail, according to the present invention, the closer the crank angle to be detected is to the intermediate position between the rising of the engine rotation pulse sandwiching the crank angle and the next rising, Since the amount of correction of the same crank angle is large, the crank angle is corrected in conformity with the curvilinear change of the actual crank angle, and a highly accurate crank is achieved while compensating for the deviation from the actual change of the actual crank angle. It has an excellent effect that the angle can be detected.

[Brief description of drawings]

FIG. 1 is an EC in a first embodiment embodying the present invention.
4 is a flowchart illustrating a main routine for fuel injection amount control executed by U.

FIG. 2 is a time chart for explaining a correspondence relationship between an engine rotation pulse and an electromagnetic spill valve operation, a spill timing pulse number and a surplus angle according to a final injection amount in the first embodiment.

FIG. 3 is a flowchart illustrating an NE interrupt routine for determining a spill pulse time executed by an ECU in the first embodiment.

FIG. 4 is a time chart for explaining a correspondence relationship between a time change of the engine rotation speed, a time change of the engine rotation pulse, and a crank angle in the first embodiment.

FIG. 5 is a graph showing a relationship between a correction angle and a remainder angle in the first embodiment.

FIG. 6 is a time chart illustrating a correspondence relationship between an engine rotation pulse and an electromagnetic spill valve operation when the spill time is less than 100 μs, a final spill time pulse number, a final spill time, and the like in the first embodiment.

FIG. 7 is a time chart for explaining the correspondence between the engine rotation pulse and the operation of the electromagnetic spill valve when the spill time is 100 μs or more, the final spill time pulse number, the final spill time, and the like in the first embodiment.

FIG. 8 is a schematic configuration diagram illustrating a fuel injection amount control device for a diesel engine in the first embodiment.

FIG. 9 is a sectional view showing a fuel injection pump in the first embodiment.

FIG. 10 is a block diagram showing a configuration of an ECU in the first embodiment.

FIG. 11 E in the second embodiment embodying the present invention
It is a flow chart explaining a part of processing routine for fuel injection timing control performed by CU.

FIG. 12 is a time chart for explaining the correspondence between engine rotation pulses and reference position signals in the second embodiment.

FIG. 13 is an explanatory diagram for explaining a temporal change of an instantaneous rotation speed of a diesel engine in a conventional example.

[FIG. 14] Similarly, in the conventional example, the time change of the rotation speed
6 is a time chart for explaining a correspondence relationship between an engine rotation pulse and a crank angle with time.

[Explanation of symbols]

1 ... Fuel injection pump, 2 ... Diesel engine, 35 ...
Rotation speed sensor, 71 ... ECU, TS1125 ... Spill pulse time, .THETA.REMa ... remainder angle, .THETA.REM ... Final remainder angle, .THETA.1 ... Reference angle, .THETA.2 ... Corrected reference angle.

Claims (1)

Claim: What is claimed is: 1. A crank angle detecting method for detecting a predetermined crank angle in the vicinity of the time when the instantaneous engine speed is the lowest, in which the engine rotation pulse from the rising edge of the engine rotation pulse obtained every fixed crank angle is detected. The crank angle is detected up to the start of, and based on the angle time required to rotate the same angle at the same crank angle position of the previous time, conversion is performed between the crank angle and time that is the detection target. In this case, the crank angle as the detection target is characterized in that the correction amount of the crank angle is increased as the crank angle is closer to an intermediate position between the rising and the next rising of the engine rotation pulse sandwiching the crank angle. Engine crank angle detection method.