JPH07139412A - Injected fuel quantity controller of diesel engine - Google Patents

Abstract

PURPOSE:To improve the control precision regardless of the revolutional fluctuation of an engine, by computing a pulse time on spilling which is a reference for converting a remaining angle insufficient to one pulse of the engine revolution to the time, on the basis of the previous pulse time. CONSTITUTION:The fuel to be injected into a diesel engine A1 is pressurized by a fuel injection pump A3 driven by the diesel engine A1 and the flow rate thereof is adjusted by a spill valve A2. In this case, a remaining angle insufficient in one pulse is operated by a means A6, based on the revolutional pulses of engine output from the means A5 and the pulse time for one pulse is operated by a means A7 and the remaining angle is converted into the time by a means A8 on the basis of the pulse time. And the spill valve A2 is controlled by a means A10 in accordance with the timing basing on the count number from the reference position to the spill position and the remaining angle-time. The remaining angle-time is operated on the basis of the previous pulse time stored in a means A9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for a diesel engine, and more particularly to a fuel injection amount control device for a diesel engine for controlling the fuel injection amount by controlling the drive of a spill valve.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection pump of an electronically controlled diesel engine, for example, an electromagnetic spill valve 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. As a result, the fuel from the high pressure chamber of the plunger overflows (spills) to the combustion chamber to control the end of the pressure feed of the fuel (that is, the end of the fuel injection) to obtain the required fuel injection amount.

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

For example, in the technique disclosed in Japanese Patent Application Laid-Open No. 62-267547, an electromagnetic spill is performed at a target spill position corresponding to the injection end timing in order to obtain a fuel injection amount that is determined according to the operating state at that time. The valve is opened and the spill port is opened. Here, in order to determine the target spill position, based on the engine rotation pulse obtained for each constant crank angle, the pulse count number from a certain reference position of the engine rotation pulse to the target spill position and one pulse are satisfied. Find the no remainder angle. The remaining angle is converted into time based on the required time for one pulse including the previous spill position (pulse time during spill).

[0005]

However, in the above-mentioned prior art, the difference in pulse time during spill becomes large when the engine rotation fluctuation is large. For example, when the instantaneous rotation speed around the target spill position this time drops compared to the instantaneous rotation speed around the previous spill position, the current spill time is longer than the previous spill time. Become.

Therefore, when the surplus angle is time-converted based on the previous spill time pulse time obtained in the state where the rotation fluctuation is large, the error of the time conversion becomes very large, and the fuel injection amount is increased. The control accuracy may have deteriorated. In addition, there is a risk that the deterioration of the accuracy of the fuel injection amount control may further induce the rotation fluctuation of the engine, resulting in a reduction in the output.

The present invention has been made in view of the above points, and the spill time pulse time, which is a reference for time conversion of the surplus angle, is the pulse time immediately before the engine rotation pulse including the current spill position or 180. Provided is a fuel injection amount control device for a diesel engine in which the accuracy of the fuel injection amount control is improved without being affected by the engine rotation fluctuation by performing a calculation based on the pulse time before or the pulse time before 720 degrees. The purpose is to

[0008]

FIG. 1 shows the principle of the present invention. As shown in the figure, the present invention is characterized by the following means in order to solve the above-mentioned problems.

According to the invention of claim 1, a diesel engine
A fuel injection pump (A3) that pressurizes fuel with the driving force generated by (A1), and sends the pressurized fuel to the diesel engine (A1) while controlling the fuel injection amount with the spill valve (A2),
Based on the fuel injection amount determined according to the operating state of the diesel engine (A1), at least spill position calculation means (A4) for calculating the valve opening timing of the spill valve (A2) corresponding to the fuel injection end timing, Based on the engine rotation pulse output from the engine rotation detection means (A5), which outputs an engine rotation pulse for each constant crank angle of the diesel engine (A1), and for each constant crank angle, A count number from the reference position to the spill position of the engine rotation pulse, a surplus angle calculation means (A6) for calculating a surplus angle less than the one pulse, and a pulse time for one pulse of the engine rotation pulse. Based on the pulse time calculation means (A7) and the pulse time of the engine rotation pulse that sandwiches the spill position calculated by this pulse time calculation means (A7), The remainder angle time conversion means a remainder angle is calculated by the calculation means (A6) for calculating a time-converted odd angle time (A8), the pulse time calculating means (A
Pulse time storage means (A9) for storing the pulse time calculated by 7), the count number from the reference position to the spill position calculated by the surplus angle calculation means (A6), and the surplus angle time conversion means (A9). The spill valve control means (A10) for driving and controlling the spill valve (A2) at a time timing determined based on the surplus angle time calculated by (A8) and the surplus angle time conversion means (A8). ) Is configured to calculate the surplus angle time based on the pulse time of the engine rotation pulse that is at least one before the engine rotation pulse that includes the spill position determined this time and that is stored in the pulse time storage means (A9). It is characterized by.

Further, in the invention of claim 2, the surplus angle time conversion means (A8) is at least one more than the engine rotation pulse including the spill position currently obtained stored in the pulse time storage means (A9). The pulse time of the previous engine rotation pulse and the pulse time of the engine rotation pulse 180 degrees before the crank angle of the engine rotation pulse including the spill position calculated this time stored in the pulse time storage means (A9). The crank angle is set to 720 rather than the engine rotation pulse including the spill position calculated this time stored in the pulse time storage means (A9).
It is characterized in that the remaining angle time is calculated based on the pulse time of the engine rotation pulse at the previous time.

[0011]

In the fuel injection amount control device of the diesel engine having the above structure, since the pulse time calculating means (A7) and the pulse time storing means (A9) are provided, the pulse time calculating means (A7) performs the calculation. The pulse time can be stored in the pulse time storage means (A9).

Therefore, the extra angle time conversion means (A8) is
(1) The pulse time of the engine rotation pulse immediately before the engine rotation pulse including the spill position obtained this time (hereinafter referred to as the spill time pulse), and (2) the engine rotation pulse 180 degrees before the spill time pulse in the crank angle. Based on the pulse time, (3) the pulse time of the engine rotation pulse 720 degrees before the spill time pulse in crank angle, it is possible to convert the surplus angle into time and calculate the surplus angle time.

The engine rotation fluctuations described above do not occur suddenly from a certain engine rotation pulse, but gradually occur depending on the engine state. Therefore, the pulse time of the engine rotation pulse including the spill position obtained this time (pulse time at spill time) and the pulse time of the engine rotation pulse immediately before the spill time pulse are extremely close to each other, and the influence of engine rotation fluctuation is almost eliminated. It is a time when I do not receive it.

Therefore, by calculating the surplus angle time based on the pulse time of the engine rotation pulse immediately before this spill time pulse, the surplus angle time can be obtained with high accuracy, whereby the accuracy of fuel injection amount control can be obtained. Can be improved.

Further, the engine rotation generally fluctuates with the cycle of the engine, has the highest speed in the explosion process, and tends to decrease in the other processes. Therefore,
The accuracy of the fuel injection amount control can be improved by calculating the surplus angle time based on the pulse time of the engine rotation pulse in the region where the engine rotation fluctuation is small.

Focusing on engine speed fluctuations, the spill pulse position is near the bottom dead center (BDC) position, and the bottom dead center (BDC) and top dead center 180 degrees before the crank angle. It is an intermediate position with respect to the point (TDC), and it is an area where the engine rotation fluctuation is small. Therefore, the crank angle is 18 more than the pulse for spill.
By calculating the surplus angle time based on the pulse time of the engine rotation pulse at 0 degree before, it is possible to improve the calculation accuracy of the surplus angle time and the accuracy of fuel injection amount control.

180 ° CA more than the above spill pulse
The previous state is a state in which the fuel injection amount control is being performed for a cylinder different from the cylinder for which fuel injection control is currently being performed. As is well known, an engine having a plurality of cylinders has a device error for each cylinder, and this also affects the engine rotation fluctuation. Therefore, by calculating the surplus angle time based on the pulse time in the same cylinder and in the same process, it is possible to cancel the device error for each cylinder. 720 degrees crank angle before the spill time pulse is in the same cylinder and in the same process state, and by calculating the remaining angle time based on the pulse time of the engine rotation pulse at this time, the calculation accuracy of the remaining angle time is calculated. Also, the accuracy of fuel injection amount control can be improved.

[0018]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing a fuel injection amount control device for a diesel engine with a supercharger in this embodiment, and FIG. 3 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.
A fuel feed pump (developed by 90 degrees in this 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 diesel engine 2 is attached to the outer peripheral surface of the pulsar 7.
The same number as the number of cylinders, that is, four cutting teeth in this case, are formed at the same angular intervals, and projections are formed at the same angular intervals between the respective cutting teeth at 3.75 ° clamp angles. 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 (four in this embodiment). 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 rotates and engages with the cam roller 10 to reciprocate in the left-right direction in the figure by the same number as the number of cylinders. Driven. Also, 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. 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. 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 in the.

Then, the drive shaft 5 is rotated to drive the fuel feed pump 6, whereby fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. Also, during the suction process in which the plunger 12 is moved back and the high pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 to the high-pressure chamber 15 by communicating one of the six with the suction port 19. On the other hand, during the compression process in which the plunger 12 is moved forward and the high-pressure chamber 15 is pressurized, the 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 an overflow adjusting valve for adjusting the fuel spill from the high pressure chamber 15 is provided in the middle of the spill passage 22. This electromagnetic spill valve 23 is a normally open type valve, and when the coil 24 is in a non-energized (off) state, the valve body 25 is opened and the high pressure chamber 1
The fuel in 5 is spilled into the fuel chamber 12. Also, coil 2
When 4 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 process of the plunger 12, the fuel in the high pressure chamber 15 is decompressed and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward, the fuel pressure in the high pressure chamber 15 does not rise while the electromagnetic spill valve 23 is open, and fuel injection from the fuel injection nozzle 4 is not performed. Further, during the forward movement of the plunger 12, by controlling the closing / opening timing of the electromagnetic spill valve 23, the fuel injection amount from the fuel injection nozzle 4 is controlled.

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 has a timer housing 27, a timer piston 28 fitted in the housing 27, and a timer piston 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 pressing and urging 28 to the pressure chamber 30 on the other side. The timer piston 28 is connected to the roller ring 9 via the slide pin 32.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 is determined by the equilibrium relationship between the fuel pressure and the urging force of the timer spring 31. Further, 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.
2 reciprocating timing is determined.

The timer device 26 is provided with a timing control valve 33 for adjusting the fuel pressure of the timer device 26, that is, the control oil pressure. 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 energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening and closing control of the timing control valve 33. The lift timing of the plunger 12 is controlled by the fuel pressure adjustment, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

On the upper part of the roller ring 9, a rotation speed sensor 35 as an engine rotation detecting means composed of an electromagnetic pickup coil is attached so as to face the outer peripheral surface of the pulsar 7. The rotation speed sensor 35 detects passage of the protrusions of the pulsar 7 and the like when the protrusions and the like of the pulsar 7 cross each other to detect engine speed NE
The engine rotation pulse is output as a timing signal corresponding to, that is, a rotation angle signal for each predetermined crank angle (every 3.75 ° CA in this embodiment). Further, since the rotation speed sensor 35 is integrated with the roller ring 9,
Regardless of the control operation of the timer device 26, a reference timing signal is output to the plunger lift at a pair of timings.

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 an auxiliary 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 assisting 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
A turbine 51 of 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, the turbocharger 48 uses the energy of exhaust gas to rotate a turbine 51 and a compressor 49 coaxially with the turbine 51 to increase the pressure of 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.

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 recirculation amount of exhaust gas is provided in the middle of the recirculation pipe 54. The EGR valve 55 is opened / closed by controlling a vacuum switching valve (VSV) 56.

Further, in the middle of the intake pipe 47, there is provided a throttle valve 58 which is opened / closed in association with the depression amount of the accelerator pedal 57. 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.

The electromagnetic spill valve 2 provided on the fuel injection pump 1 and the diesel engine 2 as described above.
3, the timing control valve 33, the glow plug 46, and the VSVs 56, 61, and 62 are electronic control devices that constitute spill position calculation means, surplus angle calculation means, surplus angle time conversion means, pulse time storage means, and spill valve control means ( (Hereinafter, simply referred to as “ECU”) 71, and their drive timings 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 an 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 for detecting a rotation reference position of the crankshaft 40 of the diesel engine 2 such as a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder is provided. Further, the transmission (not shown) is provided with a vehicle speed sensor 77 for detecting a 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, etc. are suitably controlled.

Next, the configuration of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 is a central processing unit (CPU) 81, a read-only memory (RO) in which a predetermined control program, maps and the like are stored in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the calculation result of the CPU 81, a backup RAM 84 for storing prestored data, a clock 92 for generating a predetermined clock signal, and the like, and these units and the input port 85. And the output port 86 and the like are connected by a bus 87 as a logical operation circuit.

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, 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. Also, 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 fuel injection amount control operation executed by the above-mentioned ECU 71 will be described with reference to FIGS. The flowcharts shown in FIGS. 5 and 6 are executed by the ECU 7
2 shows the fuel injection time calculation process executed by 1. The fuel injection time calculation process is performed by the rotation speed sensor 3
It is carried out as an NE interrupt routine interrupted at the rising edge of the engine speed pulse of the engine speed NE input from 5.

When the fuel injection time calculation process shown in the figure is started, first, at step 10 (step is abbreviated as S in the figure), the engine speed determined based on the engine speed pulse output from the speed sensor 35. N
The fuel injection amount SPV is calculated based on E and the accelerator opening Accp calculated from the accelerator opening sensor 73.
In the following step 12, the injection start position ANGSPS where the fuel injection is started based on the fuel injection amount SPV obtained in step 10 (that is, the position where the electromagnetic spill valve 23 is turned on) and the injection open end position ANG where the fuel injection is ended.
SPE (that is, the spill position where the electromagnetic spill valve 23 is turned off)
Is calculated. The positions of the injection start position ANGSPS and the spill position ANGSPE are shown in FIG. 7. FIG. 7 is a diagram showing an example of the engine rotation pulse and the spill valve operation in correlation with each other.

In step 12, the injection start position ANG
When the SPS and the spill position ANGSPE are obtained, in step 14, the spill pulse number CA is calculated based on these values.
NGLa and the remainder angle θREM are calculated.

Here, the spill pulse number CANGLa means the spill position A from the reference position, as shown in FIG.
This refers to the number of pulses up to one pulse before the engine rotation pulse including NGSPE (the fourth pulse corresponds to this in the present embodiment. Note that this pulse will be referred to as spill pulse hereinafter). The extra angle θREM is a crank angle from the rising position of the spill pulse to the spill position ANGSPE. Further, in the present embodiment, the reference position is a pulse output by a protrusion (tooth) formed next to the cutting tooth formation position with the rotation of the pulsar 7 among engine rotation pulses output from the rotation speed sensor 35. (In this embodiment, the rising position of the 0th pulse is used as a reference position).

Now, from the reference position to the spill position ANGSP
When the crank angle up to E (hereinafter, this crank angle is referred to as spill opening angle) is ANSPV, the spill opening angle ANGSPV is the spill pulse number C described above.
It is expressed by the following equation using ANGLa, the remainder angle θREM, and the crank angle per engine rotation pulse (3.75 ° CA).

ANGSPV = 3.75 × CANGLa + θREM ... In the following step 16, a pulse time TNINT (n-1) one pulse before the spill pulse (previous time) is calculated. Since this pulse time TNINT (n-1) is the pulse width time of the engine rotation pulse (third pulse) one time before the engine rotation pulse (fourth pulse) started by the routine processing this time, the CPU 81 determines 4 pulses preceding the pulse time by the rising time T _4U subtracting process the rising time T _4U third pulse TNINT
Calculate (n-1).

Pulse time TN calculated in step 16
INT (n-1) is the RAM 83 in step 18.
Are stored and stored in. As described above, this routine process is executed every time the engine rotation pulse is generated. Therefore,
Each time an engine rotation pulse is generated, the pulse time TNINT (n-1) that is one time before the engine rotation pulse is sequentially stored in the RAM 83, so that the pulse time TNINT for all engine rotation pulses is stored in the RAM 8.
3 is stored.

In the following step 20, the basic remainder angle time TθREM0 is calculated. Here, the basic remainder angle time TθREM0 is a time conversion of the above-mentioned remainder angle θREM. This basic surplus angle time TθREM
0 is the pulse time of spill pulse TNINT (n)
Assuming that (hereinafter referred to as spill pulse time) is known, it can be expressed by the following equation.

TθREM0 = {θREM × TNINT (n)} / 3.75 However, the actual spill pulse time TNINT (n)
Can be obtained only when the engine rotation pulse (fifth pulse) following the spill pulse is generated. Further, at the end of fuel injection, the spill position ANGS
Since PE exists before the occurrence of the fifth pulse, it is necessary to calculate the basic remainder angle time TθREM0 before the occurrence of the fifth pulse. That is, it is necessary to perform calculation before the actual spill pulse time TNINT (n) is known.

Therefore, the spill pulse time TNI required in the arithmetic processing of the basic remainder angle time TθREM0
It is necessary to estimate NT (n) in some way. Therefore, in the present embodiment, the engine rotation pulse (third pulse) one time before the spill pulse (fourth pulse) is used.
First, the basic remainder angle time TθREM0 is calculated based on the pulse time TNINT (n-1) of
It is a feature of. Basic residual angle time Tθ in the present embodiment
The arithmetic expression of REM0 is shown below.

TθREM0 = {θREM × TNINT (n−1)} / 3.75 Here, instead of the actual spill time pulse time TNINT (n), the engine one time before the spill time pulse (fourth pulse) Using TNINT (n-1) which is the pulse time of the rotation pulse (third pulse), the basic remainder angle time TθR
The reason why the calculation of EM0 is made will be described.

The engine speed fluctuation described above does not abruptly occur from a certain engine rotation pulse, but gradually occurs depending on the engine state. This will be described with reference to FIG. When the engine rotation fluctuation occurs, the pulse time TNINT of the engine rotation pulse also changes. As described above, since the spill pulse is generated in the vicinity of the bottom dead center (BDC) position, the pulse time TNINT of the engine rotation pulse becomes long in the vicinity of the spill position. Therefore, as shown in FIG.
Pulse time TNI at spill for NINT (n-4)
NT (n) is long and its time change gradually increases toward the spill pulse.

Therefore, if the basic remainder angle time TθREM0 is calculated based on the pulse time TNINT (n-4) of the 0th pulse separated from the spill pulse, the pulse time TNINT (n-4) of the 0th pulse is obtained. Since the time is significantly different from the spill time TNINT (n), the basic remainder angle time TθREM0 calculated based on the pulse time TNINT (n-4) differs from the actual value and its accuracy decreases. Will end up.

On the other hand, the pulse time TNINT (n- (n-) of the third pulse immediately before the spill pulse (fourth pulse))
1) is a time approximate to the pulse time during spill TNINT (n). Therefore, the pulse time TNINT (n- (n-
By calculating the basic remainder angle time TθREM0 by using 1), it is possible to prevent the influence of engine rotation fluctuation from being reflected in the basic remainder angle time TθREM0, and to obtain the basic remainder angle time TθREM0 with high accuracy. Therefore, it is possible to improve the accuracy of the material injection amount control.

When the basic remainder angle time TθREM0 is calculated in step 20 as described above, the process proceeds to step 22 in FIG.

In step 22, the pulse time TN sequentially stored in the RAM 83 by the processing of step 18
720 ° C of INT pulse for this spill pulse
The pulse time TNINT (n-192) before A is read.

As described above, the diesel engine 2 according to this embodiment is a four-cylinder four-cycle engine, and the crankshaft 40 rotates 720 ° CA to perform each process of intake, compression, explosion and exhaust. Has been done. Therefore, as shown in FIG. 8, the pulse time TNINT (n-192) before 720 ° CA before the current spill pulse is the spill pulse time of the previous spill pulse in the same cylinder (hereinafter referred to as the previous spill pulse). It is called time pulse time).

In step 22, the pulse time T at the previous spill was set.
When NINT (n-192) is calculated, the process proceeds to step 2
4, the pulse time TNINT (nINT (n
-192), the same cylinder correction amount ΔTθSPVX0 is calculated. Here, the same cylinder correction amount ΔTθSPV0 is
It is a correction value for reflecting the engine rotation fluctuation generated due to the device error peculiar to each cylinder in the remaining angular time TθREM.

Specific same cylinder correction amount ΔTθSPVX0
In the calculation method of, the spill time pulse time (referred to as the true spill time pulse time) TNINT0 obtained in advance in the ROM 82 without any equipment error is stored as a binary map with the engine speed NE in the ROM 82, The engine speed NE of the current diesel engine 2 is obtained from the output of the speed sensor 35, and the true spill pulse time TN is obtained.
First, INT0 is obtained. Then, based on the obtained true spill pulse time TNINT0, the same cylinder correction amount ΔTθSPVX0 is calculated by the following equation.

ΔTθSPVX0 = TNINT (n−192) −TNINT0 ... The same cylinder correction amount ΔTθSPV obtained in this way
X0 is reflected in the basic remainder angle time TθREM0 calculated in step 20 in the process of step 30 described later.

As is well known, in an engine having a plurality of cylinders, each cylinder has a device error, which affects engine rotation fluctuations. Therefore, the pulse time (TNINT (n-
192) and TNINT (n-1)), the basic residual angle time T? REM0 can be corrected to cancel the device error for each cylinder.

Therefore, the same cylinder correction amount ΔTθSPVX0
Is reflected in the basic remainder angle time TθREM0, variations in the basic remainder angle time TθREM0 between cylinders can be eliminated, and the basic remainder angle time TθREM0 can be eliminated.
The accuracy of REM0 can be improved, and the accuracy of fuel injection amount control can be improved.

In the following step 26, step 1
Of the pulse time TNINT sequentially stored in the RAM 83 by the process of 8, the current spill pulse is 180
Read the pulse time TNINT (n-48) before CA.

As is well known, the rotation of the engine fluctuates with the engine cycle, becomes the fastest in the explosion process, and tends to decrease in the other processes. Therefore,
When obtaining the basic remainder angle time TθREM0, the basic remainder angle time TθREM0 of the engine rotation fluctuation is calculated by obtaining the pulse time TNINT of the engine rotation pulse in the region where the engine rotation fluctuation is small and calculating the basic remainder angle time TθREM0 based on this. Can be eliminated.

Then, paying attention to the actual engine speed fluctuation (actual engine speed fluctuation), as shown in FIG. 8, the position where the spill pulse is generated is near the bottom dead center (BDC) position. 180 degrees before is an intermediate position between the bottom dead center (BDC) and the top dead center (TDC), which is a region where the engine rotation fluctuation is small.

Therefore, it is 18 times more than the spill pulse this time.
Pulse time T of the engine rotation pulse before 0 ° CA
Based on NINT (n-48), basic residual angle time TθRE
By obtaining M0, the basic remainder angle time TθREM
The stability of 0 can be achieved, and the accuracy of the fuel injection amount control can be improved.

Therefore, in this embodiment, 180 ° CA
Pulse time TNINT of the engine rotation pulse before
The smoothing correction amount ΔTθSPVX1 is calculated based on (n−48), and this is calculated in step 30 as the basic remainder angle time T.
By reflecting it in θREM0, the basic remainder angle time T
It is configured to stabilize θREM0. This smoothing correction amount ΔTθSPVX1 is obtained by the following equation using the above-described true spill time pulse time TNINT0.

ΔTθSPVX1 = TNINT (n−48) −TNINT0 ... The smoothing correction amount ΔTθSPVX thus obtained.
1 and the same cylinder correction amount ΔTθSPVX0 obtained in step 24 described above are the basic remainder angular time Tθ calculated in step 20 previously described in step 30.
It is reflected in REM0, and the remaining angle time TθREM is calculated. The surplus angle time TθREM can be obtained by the following equation.

TθREM = TθREM0 + k ₀ × ΔTθSPV X0 + k ₁ × ΔTθSPVX1 ………… where k ₀ and k ₁ are the same cylinder correction amount ΔTθSPVX0 and the smoothing correction amount ΔTθSPX1 as the basic surplus angle time T.
It is a constant to be reflected in θREM0.

The surplus angle time TθREM obtained in step 30 is actually the same cylinder correction is performed to suppress the variation between cylinders, and the smoothing correction is performed to eliminate the influence of engine rotation fluctuation. The value is extremely close to the remaining angle time of.

In the following step 32, step 3
The fuel injection time TSPV is calculated based on the surplus angle time TθREM obtained by 0. Here, the fuel injection time T
SPV means the time from the reference position to the spill position ANGSPE (see FIG. 7). Now, assuming that the value obtained by time-converting the spill-time pulse number CANGLa obtained in step 14 is TCANGLa, the fuel injection time TSPV is expressed by the following equation.

TSPV = TCANGLa + TθREM where TCANGLa = TNINT (n−4) + TNI
NT (n-3) + TNINT (n-2) + TNINT
(N-1) By obtaining the fuel injection time TSPV as described above,
The fuel injection time calculation process ends. Based on the fuel injection time TSPV obtained by the above series of processing, the CPU
Reference numeral 81 controls the drive of the electromagnetic spill valve 23. Specifically, the CPU 81 measures the elapsed time from the reference position using the connected clock 92, and turns on the electromagnetic spill valve 23 when the time TANGSPS from the reference position to the injection start position ANGSPS has elapsed. Then, the fuel injection is started, and when the fuel injection time TSPV obtained in step 32 has elapsed, the electromagnetic spill valve 23 is turned off and the fuel injection is ended.

At this time, as described above, the remaining angular time Tθ
REM has a value extremely close to the actual surplus angle time. Therefore, the fuel injection time TSPV calculated based on this surplus angle time TθREM is extremely accurate, and the fuel injection amount is controlled accurately. be able to.

If an inner cam type fuel injection pump capable of pressurizing fuel at a higher pressure is used instead of the so-called face cam type fuel injection pump 1 used in this embodiment, the fuel pressure increases. By doing so, it becomes necessary to perform the on / off control of the electromagnetic spill valve 23 more accurately.

That is, since the injection amount per unit time injected from the fuel injection nozzle 4 increases as the fuel pressure rises, the on / off timing of the electromagnetic spill valve 23 is slightly deviated from the predetermined timing. Then, the injected fuel amount greatly differs from the calculated predetermined injection amount. In this case, optimum engine control becomes impossible, resulting in deterioration of emission and large engine speed fluctuation.

On the other hand, in the fuel injection amount control device of the present invention, the fuel injection time TSPV can be set extremely accurately, and therefore the on / off timing of the electromagnetic spill valve 23 can be set highly accurately. Therefore, by adopting the fuel injection amount control device having the configuration of the present application, it is possible to reliably perform the fuel injection amount control even if the fuel injection pump with a high fuel pressure supplied as described above is adopted.

In the above embodiment, the surplus angle θREM is time-converted to obtain the surplus angle time TθREM, and the OFF timing (that is, the spill position) of the electromagnetic spill valve 23 is set with high accuracy based on this. However,
This processing may be applied to the injection start position ANGSPS to set the ON timing of the electromagnetic spill valve 23 with higher accuracy. With this configuration,
Both the on / off timing of the electromagnetic spill valve 23 can be set with high accuracy, and particularly with the fuel injection pump with high fuel pressure as described above, it is possible to perform highly accurate fuel injection amount control.

Further, in the above embodiment, the same cylinder correction amount Δ is obtained by the processing of steps 22 to 30.
Although both TθSPVX0 and the smoothing correction amount ΔTθSPVX1 are reflected in the basic remainder angle time TθREM0, a configuration in which the fuel injection time TSPV is calculated based only on the basic remainder angle time TθREM0 has an effect over the conventional technique. Is. In addition, the same cylinder correction amount Δ
Obviously, a configuration in which only one of TθSPVX0 and the smoothing correction amount ΔTθSPVX1 is reflected in the basic remainder angular time TθREM0 and the fuel injection time TSPV is calculated based on this is effective against the conventional technique.

[0080]

As described above, according to the present invention, it is possible to accurately set the fuel injection time by improving the calculation accuracy of the surplus angle time, and thus to improve the accuracy of the fuel injection amount control. It has features such as being able to.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a fuel injection amount control device for an over-payment diesel engine that is an embodiment of the present invention.

FIG. 3 is an enlarged sectional view showing a fuel injection pump according to an embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of an ECU in one embodiment of the present invention.

FIG. 5 is a flowchart showing a fuel injection time calculation process executed by an ECU.

FIG. 6 is a flowchart showing a fuel injection time calculation process executed by an ECU.

FIG. 7 is a diagram for explaining how to determine a spill pulse time and a fuel injection time.

FIG. 8 is a diagram for explaining how to obtain the same cylinder correction amount and the smoothing correction amount.

[Explanation of symbols]

 1 Fuel Injection Pump 2 Diesel Engine 4 Fuel Injection Nozzle 6 Fuel Feed Pump 7 Pulsar 8 Cam Plate 9 Roller Ring 10 Cam Roller 12 Fuel Pressurizing Plunger 21 Combustion Chamber 22 Spiral Channel 23 Electromagnetic Spill Valve 26 Timer Device 35 Rotation Sensor 40 Crankshaft 41 cylinder 42 piston 48 turbocharger 57 accelerator pedal 58 throttle valve 71 ECU 73 accelerator opening sensor 76 crank angle sensor 81 CPU 82 ROM 83 RAM SPV: fuel injection amount ANGSPS: injection start position ANGSPE: injection end position (spill position) CANGLa : Spill time bals number TCANGLa: Value obtained by converting CANGLa into time θREM: Surplus angle TθREM: Surplus angle time ΔTθSPVX0: Same cylinder correction ΔTθSPVX1: smoothing correction amount TSPV: fuel injection time

Claims (2)

[Claims] 1. A fuel injection pump for pressurizing fuel by a driving force generated by a diesel engine, and pumping the pressurized fuel to the diesel engine while controlling the injection amount of the fuel by a spill valve, and a fuel injection pump for the diesel engine. A spill position calculation means for calculating the valve opening timing of the spill valve corresponding to the fuel injection end timing based on the fuel injection amount determined according to the operating state, and an engine rotation pulse for each constant crank angle of the diesel engine. Based on the engine rotation pulse output from the engine rotation detection means at a constant crank angle, the count number from the reference position to the spill position of the engine rotation pulse, and one pulse thereof are satisfied. A surplus angle calculating means for calculating a remaining surplus angle and a pulse time for one pulse of the engine rotation pulse Based on the pulse time calculating means and the pulse time of the engine rotation pulse sandwiching the spill position calculated by the pulse time calculating means, the residual angle calculated by the residual angle calculating means is converted into time and the residual angle time is calculated. Surplus angle time conversion means, pulse time storage means for storing the pulse time calculated by the pulse time calculation means, count number from the reference position to the spill position calculated by the surplus angle calculation means, and the surplus angle And a spill valve control means for driving and controlling the spill valve at a time timing determined based on the surplus angle time calculated by the time conversion means, and the surplus angle time conversion means includes the pulse time storage means. At least one engine revolution pulse before the engine revolution pulse including the spill position required this time stored in Configured fuel injection quantity control device for a diesel engine comprising to calculating the 該余 Ri angle time based on the scan pulse time. 2. A fuel injection pump that pressurizes fuel by a driving force generated by a diesel engine and sends the pressurized fuel to the diesel engine while controlling the fuel injection amount with a spill valve, and the operation of the diesel engine. Based on the fuel injection amount determined according to the state, at least a spill position calculating means for calculating the valve opening timing of the spill valve corresponding to the fuel injection end timing, and an engine rotation pulse for every constant crank angle of the diesel engine Based on the engine rotation pulse output from the engine rotation detection means at a constant crank angle, the count number from the reference position to the spill position of the engine rotation pulse, and one pulse thereof are satisfied. A surplus angle calculating means for calculating a remaining surplus angle, and a pulse time for one pulse of the engine rotation pulse Based on the pulse time calculation means for calculating, and the pulse time of the engine rotation pulse sandwiching the spill position calculated by the pulse time calculation means, the surplus angle calculated by the surplus angle calculation means is converted into time and the surplus angle time is calculated. A surplus angle time conversion means for calculating, a pulse time storage means for storing the pulse time calculated by the pulse time calculation means, a count number from the reference position to the spill position calculated by the surplus angle calculation means, And a spill valve control means for driving and controlling the spill valve at a time timing determined on the basis of the surplus angle time calculated by the surplus angle time conversion means, and the surplus angle time conversion means includes the spill valve time control means. The engine at least one before the engine rotation pulse including the spill position required this time stored in the storage means. The pulse time of the rotation pulse, the pulse time of the engine rotation pulse 180 degrees before the crank angle of the engine rotation pulse including the spill position calculated this time stored in the pulse time storage means, and the pulse time storage means Fuel injection amount of the diesel engine configured to calculate the surplus angle time based on the stored pulse time of the engine rotation pulse 720 degrees before the engine rotation pulse including the spill position calculated this time Control device.