JP2885131B2 - Fuel injection timing control system for diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection timing control system for a diesel engine.

[0002]

2. Description of the Related Art In recent years, with the development of electronic control technology, especially digital control technology, a so-called electronically controlled diesel engine that electronically controls a fuel injection pump of a diesel engine has been put to practical use. There are various methods of electronically controlling the fuel injection pump in the diesel engine. One of the methods is to control the overflow of fuel in the fuel injection pump by an electromagnetic spill valve. This is because the spill port is opened by the electromagnetic spill valve at the spill timing when the fuel injection amount reaches the target value, thereby causing the fuel from the plunger high-pressure chamber to overflow (spill), and the pumping of the fuel to end, that is, the end of the fuel injection. And the required fuel injection amount is controlled.

[0003] Opening and closing of the electromagnetic spill valve is usually controlled using an engine rotation angle signal (engine rotation pulse) output at every constant crank angle. As a method of calculating the timing at which fuel overflows using the engine rotation pulse (target spill timing), for example, Japanese Patent Application Laid-Open No. 62-26
There is a “method of controlling fuel injection amount of diesel engine” disclosed in Japanese Patent No. 7547. As shown in FIG. 12, in this technique, the angle at which the electromagnetic spill valve is opened (spill opening angle ANGSPV) is given as an angle from a reference engine rotation pulse.

More specifically, the angle from the rise of the engine rotation pulse of "0" to the rise of the engine rotation pulse of "3" is a direct angle, in this case, the spill timing pulse number CANG.
L is calculated. In the engine rotation pulse of “3”, the remainder angle θ REM less than one pulse is:
In this case, it cannot be calculated directly in the combustion cycle. Therefore, the surplus angle θREM is converted into a time based on the pulse time of the engine rotation pulse with the count value CNIRQ = 3 in the previous combustion cycle. The spill pulse time TS1125 here is the time required from the rise of the engine rotation pulse of “3” to the rise of the engine rotation pulse of “4”. Therefore, the time-converted value is a predicted value. Then, the target spill timing tTSPA is calculated from the spill timing pulse number CANGL and a value obtained by converting the remainder angle θREM into time. And C
An NEGL pulse of ANGL is input and the target spill timing tT
After the SPA has elapsed, a spill opening signal is output to the electromagnetic spill valve to terminate the fuel injection.

As for the control of the fuel injection timing, the fuel injection pump is provided with a hydraulic timer connected to a roller ring for lifting the plunger by engagement with a cam plate. The fuel injection timing is controlled by driving the timer piston by duty control of a timer control valve (TCV) to change the position of the timer piston. The timer includes a synchronous control for determining the TCV driving frequency of the timer in synchronization with the on / off control of the electromagnetic spill valve, and a method of controlling the timer at a fixed frequency.

[0006] In the conventional TCV electromagnetic spill valve synchronous drive control, when the plunger pressure feed drive reaction force is TCV ON (T
In order to prevent the timer from becoming uneasy, the spill timing pulse number CAN
By using the GL + 1 NE pulse interrupt,
TCV ON control is being performed. The reason why the TCV ON time is set to the spill timing pulse number CANGL + 1 is that when the duty ratio in the synchronous control is large, the end of the TCV ON period (opening of the TCV communication passage) takes place in the next pressure feed stroke of the plunger cam. This is to avoid receiving the reaction force of the pumping.

[0007]

However, even if a spill opening signal is sent to the electromagnetic spill valve as shown in FIG.
The response delay time t before the electromagnetic spill valve is actually opened
TSPVD exists. Therefore, when the remaining angle θREM is equal to or more than a certain value, the actual spill valve opening timing including the response delay time tTSPVD may exceed CANGL + 1. As a result, even though the spill reaction force is still applied to the timer piston, the TCV is ON, so that the stability of the timer device is deteriorated, so that the fuel injection timing varies and the emission is deteriorated.

The present invention has been made in view of the above-described circumstances, and has as its object the actual fuel spill timing and TCV.
An object of the present invention is to provide a fuel injection timing control device for a diesel engine, which can prevent the ON timings of the engine from being overlapped and stabilize a timer.

[0009]

In order to achieve the above object, the present invention provides a diesel engine M as shown in FIG.
A crank shaft M2 that is provided rotatably in 1, engine in each predetermined unit angle with the rotation of the crank shaft M2
Angle detection means M for generating a rotation pulse and detecting a crank angle which is a rotation angle of the crankshaft M2.
3 and pressurizing the fuel in a high-pressure chamber by a plunger reciprocally driven via a cam in conjunction with the rotation of the diesel engine M1.
1 and pressurized in the high-pressure chamber to repeat the combustion cycle by executing combustion in the diesel engine M1 at every predetermined crank angle.
A fuel injection pump M5 provided with an electromagnetic spill valve as an actuator M4 for adjusting a control amount such as a fuel injection amount of the diesel engine M1 by repeatedly spilling and stopping the fuel; and a fuel from the fuel injection pump M5. A timer M6 having a timer piston driven by control hydraulic pressure to change the reciprocating drive timing of the plunger via the cam to control the injection timing, and a timer M6 controlled to adjust the control hydraulic pressure in the timer M6. A timer control valve M7, a timer control means M8 for controlling the timer control valve M7, an operation state detection means M9 for detecting an operation state of the diesel engine M1, and an operation state detected by the operation state detection means M9. In order to obtain the target control amount of the diesel engine M1, the electromagnetic spill valve M
4 is the spill opening angle ANG
Operating crank angle calculating means M10 to be determined as SPV
Pressurized in the high-pressure chamber at a timing calculated based on the calculation result of the operating crank angle calculating means M10.
The control device for a diesel engine equipped with an actuator control means M11 for operating the electromagnetic spill valve M4 so as to spill the fuel, the spill opening angle AN
GSPV divided by the angle of one of the engine rotation pulses
The quotient obtained as the spill time pulse number CANGL, the remainder
When the minute is the remainder angle θREM, the timer control means
M8 is the angle conversion value tANGSP of the spill response delay time
The sum of VD and the remainder angle θ REM is calculated by the spill timing parameter.
Angle tAN from Lus number CANGL to actual spill valve opening
GDRV and the actual spill valve
The angle tANGDRV before Symbol engine rotation pulse of one minute
The angle tANGD up to the actual spill valve opening compared to the angle tANGD
When RV is less than the angle of one engine rotation pulse
Includes the count of engine rotation pulses from the reference position signal.
Judge whether the default value CNIRQ is CANGL + 1
If the answer is YES, the timing of CANGL + 1
The synchronous control of the timer control valve M7 is executed by
The angle tANGDRV until the actual spill valve opens is determined by the engine
When the angle is more than one rotation pulse angle, the reference position signal
Count value CNIRQ of the engine rotation pulse from
ANGL + 2 is determined, and YES is determined.
Then, the timer control is performed at the timing of CANGL + 2.
The gist is a fuel injection timing control device for a diesel engine that executes synchronous control of the valve M7 .

[0010]

[0011]

[0012]

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a fuel injection amount control device for a vehicle diesel engine as an internal combustion engine will be described with reference to FIGS.

FIG. 2 shows a diesel engine 2 with a supercharger,
FIG. 2 is a schematic configuration diagram showing a distribution type fuel injection pump 1 that injects fuel into the diesel engine 2 and a fuel injection amount control device that controls the fuel injection pump 1 to adjust the amount of fuel injection into the diesel engine 2. . FIG. 3 is FIG.
It is an expanded sectional view of the fuel injection pump 1 inside.

As shown in FIG. 2, the fuel injection pump 1 includes a drive pulley 3 which is drivingly connected to a crankshaft 40 of the diesel engine 2 via a belt or the like. The rotation of the drive pulley 3 causes the fuel injection pump 1
Is driven, and fuel is fed under pressure to a fuel injection nozzle 4 provided for each cylinder of the diesel engine 2 to perform fuel injection.

As shown in FIG. 3, a drive shaft 5 is connected to the drive pulley 3. A fuel feed pump (developed by 90 degrees in the figure) 6 composed of a vane type pump and a disk-shaped pulsar 7 having a plurality of projections on the outer peripheral surface are attached to the drive shaft 5.
The base end (the right end in the figure) of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown). A roller ring 9 is interposed between the pulsar 7 and the cam plate 8, and a plurality of cam rollers 10 facing the cam face 8 a of the cam plate 8 are mounted on the roller ring 9. The cam plate 8 is constantly biased and engaged with the cam roller 10 by the spring 11.

A plunger 12 for fuel pressurization is attached to the cam plate 8 so as to be integrally rotatable, and the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via a coupling, whereby the cam plate 8 is rotated. 8 and the plunger 12 are reciprocally driven in the horizontal direction in the figure while rotating. The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and the plunger 12
A high-pressure chamber 15 is formed between the front end surface (right end surface in the figure) and the inner bottom surface of the cylinder 14. The same number of intake grooves 16 and distribution ports 17 as the number of cylinders of the diesel engine 2 are formed on the outer periphery of the distal end of the plunger 12. Further, a distribution passage 18 and a suction port 19 are formed in the pump housing 13 corresponding to the suction groove 16 and the distribution port 17.

When the fuel feed pump 6 is driven based on the rotation of the drive shaft 5, fuel from a fuel tank (not shown) is supplied into the fuel chamber 21 through the fuel supply port 20. In the suction stroke in which the plunger 12 moves to the left in the drawing (returns) and the high-pressure chamber 15 is depressurized, one of the suction grooves 16 communicates with the suction port 19 to move the fuel chamber 21 from the high-pressure chamber 15. Fuel is introduced to On the other hand, the plunger 12 moves rightward in the figure (forward movement).
In the compression stroke in which the high-pressure chamber 15 is pressurized, the fuel is pressure-fed from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder and injected.

A spill passage 22 for fuel overflow that connects the high pressure chamber 15 to the fuel chamber 21 is provided in the pump housing 13.
Is formed, and an electromagnetic spill valve 23 as an actuator is provided on the way. The electromagnetic spill valve 23 is a normally open type valve. When the coil 24 is not energized (off), the valve body 25 is opened and the fuel in the high-pressure chamber 15 overflows to the fuel chamber 21. When the coil 24 is energized (turned on), the valve body 25 is closed, and the overflow 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 electromagnetic spill valve 23 is controlled to close and open, and the overflow rate of fuel from the high-pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel in the high-pressure chamber 15 is reduced in pressure, and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even when the plunger 12 moves forward, the high-pressure chamber 15 remains open while the electromagnetic spill valve 23 is open.
The fuel pressure in the inside does not increase, and the fuel injection from the fuel injection nozzle 4 is not performed. Also, during the forward movement of the plunger 12,
By controlling the timing of closing and opening the electromagnetic spill valve 23, the amount of fuel injected from the fuel injection nozzle 4 is controlled.

Below the pump housing 13, a timer device (developed by 90 degrees in the figure) 26 for controlling the fuel injection timing is provided. The timer device 26 as a timer controls the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5 so that the cam face 8
The timing a controls the cam roller 10 to engage with the cam roller 10, that is, the reciprocating timing of the cam plate 8 and the plunger 12.

The timer device 26 is operated by hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the timer housing 27, and a low-pressure chamber 29 on one side of the timer housing 27. It includes a timer spring 31 for urging the timer piston 28 toward the other pressure chamber 30 and the like. The timer piston 28 is connected to the roller ring 9 via a 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 balance between the fuel pressure and the urging force of the timer spring 31. Accordingly, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

In order to control the fuel pressure of the timer device 26, a communication passage 34 connecting the pressurizing chamber 30 and the low-pressure chamber 29 has a timing control valve (T
CV) 33 is provided. The TCV 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 opening and closing the TCV 33. Then, 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 constituting a part of the crank angle detecting means and the operating state detecting means is mounted so as to face the outer peripheral surface of the pulser 7. The rotation speed sensor 35 is made up of an electromagnetic pickup coil, and outputs a detection signal every time a protrusion formed on the outer peripheral surface of the pulser 7 crosses. Then, the rotational speed of the fuel injection pump 1, that is, the rotational speed per hour of the crankshaft 40 in the diesel engine 2 is detected from the detection signal.

In this embodiment, as shown in FIG. 5, the protrusions of the pulsar are two teeth at every 90 ° (180 ° CA crank angle) from the state where 64 pulsars are arranged at equal intervals. It has a configuration in which a tooth portion 7a is formed. For this reason,
When the diesel engine 2 rotates, as shown by the detection output after waveform shaping in FIG.
At each 11.25 ° CA, an engine rotation pulse is output from each tooth, and at the 14th engine rotation pulse, 11.25 ° CA × 3 = 33.
One 75 ° CA engine rotation pulse (reference position signal) is output.

That is, on the outer peripheral surface of the pulsar 7, the same number of cylinders of the diesel engine 2, that is, in this case, four missing tooth portions 7a are formed at equal angular intervals, and further, the adjacent missing tooth portions 7a are formed. 14 pieces in between (56 in total)
Are formed at equal angular intervals. for that reason,
By shaping the waveform of the detection signal from the rotation speed sensor 35, a reference position signal synchronized with the fuel injection cycle and a rotation signal representing the rotation speed can be obtained.

Note that CNIRQ in FIG. 6 is a count value (initial value 0) of the counter, and indicates the number of engine rotation pulses after the reference position signal is output. Further, since the rotation speed sensor 35 is integrated with the roller ring 9, the rotation speed sensor 35 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. As shown in FIG. 2, in this diesel engine 2, a cylinder 41, a piston 42 and a cylinder head 43 are provided.
Accordingly, a main combustion chamber 44 is formed for each cylinder, and a sub-combustion chamber 45 is connected to each main combustion chamber 44. Then, the fuel injected from each fuel injection nozzle 4 is supplied to each sub combustion chamber 45. A glow plug 46 as a start-up assisting device is attached to each sub-combustion chamber 45.

In the diesel engine 2, a series of operations including suction, compression, explosion, and exhaust are performed by the piston 4.
2, four strokes, that is, two rotations of the crankshaft 40. In the suction stroke, the piston 42 descends from the top dead center to the bottom dead center. At this time, air is sucked into the cylinder 41 by the negative pressure generated in the cylinder 41.

In the compression stroke, the piston 42 rises from bottom dead center to top dead center. Then, the air sucked into the cylinder 41 in the suction stroke is sent to the sub-combustion chamber 45, and becomes high pressure and high temperature. At the end of the compression stroke, the fuel injection nozzle 4 is opened, and mist-like fuel is injected into the sub-combustion chamber 45.

The injected fuel is supplied to the auxiliary combustion chamber 4 during the explosion stroke.
It mixes with the air in 5 and causes self-ignition. The temperature and pressure rise due to the ignition, and the remaining fuel is injected into the main combustion chamber 44 above the piston 42. Due to this ejection, the fuel is further atomized, sufficiently mixed with the air in the main combustion chamber 44, and rapidly burned. The combustion gas is expanded by the heat generated at this time, and the piston 42 is pushed downward. The pressing force at this time is
The rotation is changed to a rotational motion, and is used as power for moving the vehicle.

After the piston 42 is pushed down to the vicinity of the bottom dead center in the explosion stroke, the exhaust valve is opened in the subsequent exhaust stroke, and the combustion gas is pushed out of the cylinder 41 as the piston 42 rises. When the piston 42 reaches the top dead center, it returns to the initial state of the suction stroke.

Thus, the diesel engine 2
Means that the four strokes of suction, compression, explosion, and exhaust have been completed, and the crankshaft 40 has rotated twice to perform one operation of generating power. In the present embodiment, a period from the time when combustion is performed in the explosion process to the time when combustion is performed in the next explosion process is defined as a combustion cycle.

An intake pipe 47 and an exhaust pipe 50 are connected to the diesel engine 2, respectively. A compressor 49 of a turbocharger 48 is provided in the intake pipe 47, and a turbine 5 of the turbocharger 48 is provided in the exhaust pipe 50.
1 is provided. A waste gate valve 52 for adjusting the supercharging pressure is attached to the exhaust pipe 50.

The exhaust pipe 50 and the intake pipe 47 are connected to the recirculation pipe 5.
The exhaust pipe 50 is connected to the exhaust pipe 50 so that a part of the exhaust gas can be recirculated to the intake pipe 47. An EGR valve 55 for adjusting the amount of exhaust gas recirculation (EGR amount) is provided in the middle of the recirculation pipe 54. This E
The negative pressure applied to the diaphragm chamber of the GR valve 55 is:
It is controlled by a vacuum switching valve (VSV) 56.

Further, a throttle valve 58 which is opened and closed in conjunction with an accelerator pedal 57 provided in a driver's seat is provided in the intake pipe 47. A bypass 59 is formed in parallel with the throttle valve 58, and a bypass throttle valve 60 is provided in the bypass 59 so as to be openable and closable. The opening and closing of the bypass throttle valve 60 is controlled by an actuator 63. Actuator 63
, A negative pressure generated by a negative pressure pump (not shown) is supplied via two VSVs 61 and 62.

The electromagnetic spill valve 23, the TCV 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 their drive timing is controlled by the ECU 7.
1 is controlled.

As sensors for detecting the operating state of the diesel engine 2, the following sensors are provided in addition to the rotation speed sensor 35. An intake air temperature sensor 72 for detecting the intake air temperature of the air taken into the intake pipe 47 via the air cleaner 64, and an accelerator opening sensor for detecting an accelerator opening ACCP corresponding to the load of the diesel engine 2 from the open / close position of the throttle valve 58. 73, an intake pressure sensor 74 for detecting a supercharging pressure in the intake port 53, a water temperature sensor 7 for detecting a cooling water temperature of the diesel engine 2
5. The rotation reference position of the crankshaft 40 of the diesel engine 2, for example, the crankshaft 40 with respect to the top dead center of the specific cylinder.
And a vehicle speed sensor 77 that detects the running speed (vehicle speed) of the vehicle by turning on / off a reed switch 77b by a magnet 77a rotated by rotation of a gear of a transmission (not shown). Is provided.

The ECU 71 includes the above-described sensors 3
5, 72 to 77 are respectively connected. And E
The CU 71 suitably controls the electromagnetic spill valve 23, the TCV 33, the glow plug 46, and the VSVs 56, 61, 62 based on signals output from the sensors 35, 72 to 77.

Next, the configuration of the ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 has a central processing unit (CPU) 81, a read-only memory (RO) storing a predetermined control program, a map, and the like in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the calculation results of the CPU 81, a backup RAM 84 for storing previously stored data, an input port 8
5 and an output port 86 connected by a bus 87 as a logical operation circuit. Of these, CPU 81
Constitutes an operating crank angle detecting means, a surplus angle calculating means, a pulse time calculating means, a predicted pulse time calculating means, an angle time converting means, an actuator controlling means and a controlling means.

The input port 85 is connected to the intake air temperature sensor 7.
2. The accelerator opening sensor 73, the intake pressure sensor 74, and the water temperature sensor 75 are connected via buffers 88, 89, 90, 91, a multiplexer 92, and an A / D converter 93. The input port 85 includes the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77,
It is connected via a waveform shaping circuit 95. And C
The PU 81 reads, as an input value, a detection signal of each of the sensors 35, 72 to 77, etc., which is input through the input port 85. The output ports 86 are connected to drive circuits 96, 97, 9
8, 99, 100, 101 via electromagnetic spill valve 23,
TCV33, glow plug 46 and VSV56, 61,
62 and the like are connected.

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

In this embodiment configured as described above, a constant crank angle (target spill timing) is calculated in order to calculate the timing at which the electromagnetic spill valve 23 in the closed state is opened to overflow fuel (target spill timing). An engine rotation pulse (see FIGS. 6 and 7) output every 11.25 ° CA) is used. In calculating the target spill timing, an operating crank angle for opening the electromagnetic spill valve 23 (spill opening angle ANGSPV)
Is given by an angle from a reference engine rotation pulse (in FIG. 6, the rising edge of the engine rotation pulse with the count value CNIRQ = 0).

More specifically, the angle from the rise of the engine rotation pulse of "0" to the rise of the engine rotation pulse of "3" is calculated as a direct angle, in this case, the spill timing pulse number CANGL which is the number of pulse signals. Also,
The remainder angle θ REM less than one pulse of the engine rotation pulse of “3” cannot be directly calculated in the current combustion cycle. For this reason, the surplus angle θ REM
Is the pulse time of the engine rotation pulse near the spill timing in the previous combustion cycle (the pulse time TS in FIG. 7).
Time conversion is performed based on 2). This time-converted value is represented by the spill time TSPON.

Next, the operation and effect of the embodiment constructed as described above will be described. The flowchart of FIG. 8 shows a routine for calculating the spill time TSPON among the processes executed by the CPU 81. This spill time calculation routine is executed at a predetermined timing. Further, the flowchart of FIG.
3 shows a PV synchronization control calculation routine. This TCV33 S
The PV synchronization control calculation routine is interrupted and executed every time an engine rotation pulse from the rotation speed sensor 35 rises. Hereinafter, the processing of each routine will be sequentially described.

First, the spill time calculation routine of FIG. 8 will be described. In step 101, the CPU 81 reads the engine speed NE from the speed sensor 35 and the accelerator opening ACCP from the accelerator opening sensor 73, respectively, and calculates the spill opening angle ANGSPV in step 102 using both values NE and ACCP. The spill opening angle ANGSPV is an angle from the generation of the reference position signal to the time when the electromagnetic spill valve 23 is opened (turned off).

Next, in step 103, the CPU 81 calculates the spill timing pulse number CANGL and the surplus angle θ REM based on the following equation (1). ANGSPV = 11.25 × CANGL + θREM (1) That is, the spill opening angle ANGSPV is divided by “11.25” corresponding to the angle of one engine rotation pulse, and the quotient is set as the spill timing pulse number CANGL. The surplus is defined as a surplus angle θREM. Here, the spill timing pulse number CANGL is the number of pulse signals generated from the point of generation of the reference position signal to the pulse signal immediately before the spill opening angle ANGSPV ("3" in FIG. 8). The remaining angle θREM is the remaining angle from the pulse signal immediately before the spill opening angle ANGSPV to the spill opening angle ANGSPV, which is less than one pulse (11.25 ° CA).

Next, the CPU 81 determines in step 104 the three pulse times TS1 and TS3 of the engine rotation pulse.
2. In step 105, one of the read pulse times TS1 to TS3 is selected based on the spill opening angle ANGSPV in step 102, and this is burned in step 105. It is used for calculating the spill time TSPON in the cycle. That is, the pulse time TSi near the spill opening angle ANGSPV in the previous combustion cycle
And spill opening angle ANGSP in this combustion cycle
Based on V, the time required for one pulse signal in the current combustion cycle, which is predicted to include the latter spill opening angle ANGSPV, is determined.

Next, CPU 81 at step 106, sets a pulse time TSi selected in step 105 as a spill during the pulse time TS 1125. The spill time pulse time TS 1125 is the pulse time of the engine rotation pulse predicted to include the moment when the electromagnetic spill valve 23 is closed in the current combustion cycle.

Next, in step 107, the CPU 81 calculates the spill time TSPON according to the following equation (2) using the surplus angle θ REM in step 103 and the spill time pulse time TS1125.

TSPON = (θREM / 11.25) · TS1125 (2) As described above, the surplus angle θ is obtained by the processing in step 103.
The REM is converted to a time to obtain a calculated spill time tTSPA.

In this step 107, EC
Considering the operation speed of U81, the calculated spill time tTSP
It is determined whether or not A is equal to or greater than a predetermined value T (the minimum value of the interrupt processing time of the CPU 81). Spill time calculation value tTS
When PA is equal to or greater than a predetermined value T, the calculated spill time t
TSPA is used as it is as the spill time TSPON, and the spill timing pulse number CANGL is stored as it is.

If the calculated spill time tTSPA is smaller than the predetermined value T, the sum of the calculated spill time tTSPA and the spill time pulse time TS1125B is calculated, and this value is set as the spill time TSPON. The value obtained by subtracting 1 from the spill timing pulse number CANGL is stored. The spill pulse time TS1125
B sets the spill pulse time TS1125 to the pulse time T
Any one pulse time TS from S1 to TS3
When i is selected, this is the pulse time immediately before the selected TSi.

Thereafter, the CPU 81 ends the spill time calculation routine. In step 103, the spill timing pulse number CANGL is obtained.
When the spill time TSPON is obtained at 07, the CPU 8
1 outputs a signal for turning off the electromagnetic spill valve 23 based on both values CANGL and TSPON. Then, end timing, i.e. the fuel injection amount of the fuel injected from the fuel injection pump 1 by opening valve operation of the electromagnetic spill valve 23 is adjusted.

Next, the SPV synchronization control calculation routine of the TCV 33 will be described with reference to the flowchart shown in FIG.
When entering this routine, the CPU 81 proceeds to step 201.
It is determined whether the spill time TSPON is equal to or greater than a predetermined value T (the minimum value of the interrupt processing time of the CPU 81) in consideration of the calculation speed of the ECU 81. Spill time TSP
If ON is smaller than the predetermined value, step 2 described later
Move to 05. When the spill time TSPON is equal to or longer than the predetermined value T, in step 202, the spill response delay time tTSPD and the spill time pulse time TS1125 are set.
Is used to calculate the angle conversion value tANGSPVD.

TANGSPVD = (tTSPD / TS1125) * 11.25 ° CA The spill response delay time tTSPD is a value obtained in advance by actual measurement, test, or the like.

Next, in step 203, the angle t from the spill timing pulse number CANGL to the actual spill valve opening is t.
ANGDRV is converted to spill response delay time angle conversion value tANG
It is calculated by SPD and the remaining angle θREM according to the following equation.

TANGDRV = tANGSPVD + θREM Next, in step 204, the CPU 81 determines whether or not the angle tANGDRV up to the actual spill valve opening is 11.25 ° CA or more. If it is determined in step 204 that the angle tANGDRV up to the actual spill valve opening is equal to or greater than 11.25 ° CA, the process proceeds to step 205. In step 205, the CPU 81 determines that the count value CNIRQ of the engine rotation pulse from the reference position signal is CAN.
It is determined whether or not GL + 2. If YES is determined in step 205, TCV synchronization control is executed in step 206, and this routine ends. That is, if the count value CNIRQ is CANGL
When the TCV synchronous control is executed at +1, since the angle tANGDRV up to the actual spill valve opening is 11.25 ° CA or more, a spill reaction force is applied to the timer piston 28, so that the count value CNIRQ becomes CANGL.
The TCV synchronization control is performed at +2.

If the determination in step 205 is NO, that is, if the count value CNIRQ is equal to CAN.
If GL + 2 has not been reached, it is determined that it is not time for TCV synchronous control, and the process exits from this processing routine.

On the other hand, in step 204, NO
If it is determined that the
81 determines whether or not the count value CNIRQ of the engine rotation pulse from the reference position signal is CANGL + 1. If YES is determined in step 207,
In step 206, TCV synchronization control is executed, and this routine ends. That is, the TCV synchronization control is executed when the count value CNIRQ is CANGL + 1, as in the related art. Even if this TCV synchronous control is executed, the angle tANGDRV until the actual spill valve opens is 11.25 °.
Since it is less than CA, the spill reaction force is not applied to the timer piston 28, so that the TCV synchronous control is performed with the count value CNIRQ being CANGL + 1.

When it is determined NO in step 207, that is, when the count value CNIRQ is set to CAN.
If GL + 1 has not been reached, it is determined that it is not time for TCV synchronous control, and the process exits from this processing routine.

On the other hand, if the CPU 81 determines in step 201 that the spill time TSPON is less than the predetermined value T (the minimum value of the interrupt processing time of the CPU 81), the process proceeds to step 205. In this case, in step 107 of the spill time calculation routine, the spill time calculation value tTSPA and the spill time pulse time TS1125 are used.
B, and calculates the sum as the spill time TSPON, and calculates the spill timing pulse number CA calculated in step 103.
A value obtained by subtracting 1 from NGL is stored.

As a result, the spill timing pulse number CANGL
Is (CANGL-1), so step 20
In 5, the CPU 81 determines that the count value CNIRQ of the engine rotation pulse from the reference position signal is equal to the new CANGL +
2 is determined. Step 205
If YES is determined in step, the TCV synchronization control is executed in step 206, and this routine ends. If the determination in step 205 is NO, that is, if the count value CNIRQ is equal to CANGL + 2
If it has not reached this time, it is determined that it is not time for the TCV synchronous control, and the process once exits from this processing routine.

According to the SPV synchronous control of the TCV 33 as described above, after the steps 201 to 206, as shown in FIG. 10A, the control of the TCV 33 is performed at (CANGL + 2). Step 20
1 to step 204, step 207, step 206
, The TCV 33 as shown in FIG.
Is turned on at (CANGL + 1 ). Further, Step 201, Step 205, Step 206
, The TCV 33 as shown in FIG.
Is turned on at (CANGL + 1).

In any case, since the TCV 33 is turned on at a time later than the angle tANGDRV until the actual spill valve opens, that is, after the spill reaction force has disappeared, the stability of the timer device 26 is improved. In addition, the fuel injection timing does not vary, and the emission does not deteriorate.

That is, since the pressure in the high-pressure chamber 15 during spill is higher than the pressure reaction force at the start of the compression stroke of the plunger 12, the spill reaction force immediately before spill is much larger. In this embodiment, since the TCV 33 is controlled to be turned on after the spill reaction force has disappeared, the timer device 26 can be stabilized.

In the above-described embodiment, the present invention is embodied in the diesel engine 2 provided with a supercharger (turbocharger 48). However, a diesel engine provided with a supercharger as a supercharger, It can also be embodied in a diesel engine that does not have a diesel engine.

[0070]

[0071]

As described above in detail, according to the present invention, after the spill reaction force has disappeared, the opening of the timer control valve is controlled, so that the stability of the timer is improved and the fuel injection timing is reduced. The emission can be prevented from deteriorating without variation. Further, since the timer control valve is controlled to open according to the response delay time of the actuator, the ON operation of the timer control valve is performed at a suitable time.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of the present invention.

FIG. 2 is a schematic configuration diagram showing a diesel engine with a supercharger, a fuel injection pump, and a fuel injection amount control device according to one embodiment.

FIG. 3 is an enlarged sectional view showing only a fuel injection pump in FIG. 2;

FIG. 4 is a block diagram showing an electrical configuration of an ECU in one embodiment.

FIG. 5 is a side view of the rotation speed sensor.

FIG. 6 is an explanatory diagram showing a detection waveform of a rotation speed sensor.

FIG. 7 is an explanatory diagram showing the relationship between the engine rotation pulse and the operation of the electromagnetic spill valve when converting the surplus angle into time.

FIG. 8 is a flowchart illustrating a spill time calculation routine.

FIG. 9 is a flowchart illustrating an SPV synchronization control calculation routine of the TCV.

FIG. 10 is an explanatory diagram showing the relationship between the electromagnetic spill valve and the operation of the TCV.

FIG. 11 is an explanatory diagram showing the relationship between the electromagnetic spill valve and the operation of the TCV according to the related art.

FIG. 12 is an explanatory diagram showing a relationship between a detection waveform of a rotation speed sensor and an operation of an electromagnetic spill valve in the related art. 2 ... Diesel engine, 23 ... Electromagnetic spill valve as actuator, 26 ... Timer device as timer, 2
8: Timer piston, 33: TC as timer control valve
V, 35: a rotational speed sensor constituting a part of the crank angle detecting means and a part of the operating state detecting means, 40: a crankshaft, 73
... Accelerator opening sensor which forms a part of operating state detecting means, 81 ... Crank angle calculating means during operation, surplus angle calculating means, pulse time calculating means, predicted pulse time calculating means, angle time converting means, control means, actuator CPU constituting the control means, NE: engine speed as operating state of diesel engine, ACCP: accelerator opening as operating state of diesel engine, ANGSPV: spill opening angle as operating crank angle, CANGL ...
Spill timing pulse number as number of pulse signals, θREM
... Remainder angle, TS1, TS2, TS3, TSi ... Pulse time near the spill opening angle in the previous combustion cycle,
TSPON: spill time as time conversion value of surplus angle; TS1125: spill time pulse time.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/40 F02D 1/18 F02D 45/00 362 F02M 41/12 320 F02M 41/12 350

Claims (1)

(57) [Claims] 1. A crank shaft rotatably provided in a diesel engine, for each predetermined unit angle with the rotation of the crankshaft d
A crank angle detecting means for generating a engine rotation pulse and detecting a crank angle which is a rotation angle of the crankshaft; and a plunger reciprocally driven via a cam in conjunction with the rotation of the diesel engine to a high pressure chamber. The fuel is pressurized in the high-pressure chamber to inject fuel into the diesel engine and perform combustion in the diesel engine at every predetermined crank angle to repeat a combustion cycle. Fuel spill and fuel
An actuator for adjusting the control amount such as the fuel injection amount of the diesel engine by repeatedly stopping the pill
A fuel injection pump having an electromagnetic spill valve , and in order to control fuel injection timing from the fuel injection pump,
A timer having a timer piston driven by control hydraulic pressure to change the reciprocating drive timing of the plunger via the cam; a timer control valve controlled to adjust control hydraulic pressure in the timer; and the timer control Timer control means for controlling a valve; operating state detecting means for detecting an operating state of the diesel engine; and an electromagnetic spill valve for obtaining a target control amount of the diesel engine according to an operating state of the operating state detecting means. The spill opening angle ANGS
Operating crank angle calculation means to be obtained as PV ; and fuel pressurized in the high-pressure chamber at a timing calculated based on a calculation result of the operation crank angle calculation means.
A control unit for operating the electromagnetic spill valve for spilling , wherein the spill opening angle ANGSPV is controlled by the engine rotation pulse.
The quotient obtained by dividing by the angle of one pulse
If the angle is CANGL and the surplus is the angle θREM,
The timer control means converts the angle of the spill response delay time into an angle.
The sum of the value tANGSPVD and the remainder angle θ REM
The actual spill BenHirakuma from the serial spill time the number of pulses CANGL
At the angle tANGDRV at
The angle tANGDRV up to the opening of the pill valve is changed by the engine rotation.
Compared with the angle of one pulse, the angle tANGDRV up to the actual spill valve opening is
When the angle is less than one gin rotation pulse, the reference position
Count value CNIRQ of engine rotation pulse from signal
Is determined to be CANGL + 1, and YES is determined.
Then, at the timing of CANGL + 1, the timer
The synchronous control of the control valve is executed, and the angle tANGDRV until the actual spill valve is opened is determined by the engine.
When the angle is more than the angle of one gin rotation pulse, the reference position
Count value CNIRQ of engine rotation pulse from signal
Is determined to be CANGL + 2, and YES is determined.
Then, at the timing of CANGL + 2, the timer
A fuel injection timing control device for a diesel engine that performs synchronous control of control valves .