JPS60187738A - Method of controlling fuel injection quantity independently for each cylinder of electronically controlled diesel engine - Google Patents

Abstract

PURPOSE:To prevent increasing of fluctuation of the idling speed and increasing of vibration of an engine, by employing such an arrangement that individual control of cylinders is reset immediately when the timing for picking up a reference engine speed is deviated due to noises, misfiring or other reason or when error is caused in the cylinder on which correction is to be made. CONSTITUTION:Judgement is made whether the actual engine speed corresponding to a reference speed that is to be the lowest of a plurality of engine speeds indicated between explosions of a plurality of cylinders is the lowermost speed or not. In case of YES, individual control of cylinders is executed continuously. However, in case of NO, the individual control of cylinders is stopped and a new individual control of cylinders is recommenced on the basis of the crank angle corresponding to the actual lowermost engine speed. By employing such a method, deviation of the timing for executing individual correction for cylinders or error in the cylinder on which correction is to be made is not caused even if noises, misfiring or momentary disconnection of the battery voltage is caused. Therefore, it is enabled to control the injection quantity of fuel individually for a plurality of cylinders.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fuel injection amount control method for each cylinder of an electronically controlled diesel engine, and in particular, among a plurality of engine rotational speeds during the explosion of each cylinder, suitable for use in an electronically controlled diesel engine for automobiles. The present invention relates to an improvement in a method for controlling fuel l'iil injection for each cylinder in an electronically controlled diesel engine, in which the amount of fuel injection is controlled for each cylinder based on the lowest engine speed.

[Prior art]

In general, diesel engines have a much larger vibration during idling than gasoline engines, and the diesel engine, which is elastically supported by the engine surroundings, resonates due to its vibrations, which reduces the comfort of the vehicle. In addition to worsening the problem, there were cases where it had a negative impact on equipment around the engine. For example, in the case of a four-cycle diesel engine, this is due to the 1/2-order low frequency with respect to the engine rotation, which is caused by periodic variations in the fuel pumped to each cylinder at half the speed of the diesel engine rotation. Mainly caused by vibration. That is, in a diesel engine, between the cylinders;! If the i-fuel injection amount varies, as shown in Figure 1, it will be different for each explosion cylinder (for 4 cylinders, every 180° CA (crank angle)).
The rotational fluctuations ΔNE are not equal, and a crank rotation fluctuation S occurs once every 4 times in 114 shots, which causes discomfort to the vehicle occupants. In the figure,
TDC is top dead center. For this reason, it is possible to manufacture the engine body, fuel injection pump, and injection nozzle with extremely high precision to reduce the variation in fuel supplied to each cylinder, but this requires a large amount of production technology. In addition to being expensive, the fuel injection pump and the like become extremely expensive. On the other hand, it is possible to suppress engine vibration by improving the engine mount gutter groove, but what about the mount mechanism? ! This has the problem that it is both expensive and expensive, and cannot be used as a fundamental countermeasure because it does not suppress the vibrations of the diesel engine itself. In order to solve this problem, for example, as shown in FIG. 2, the NE raw waveform is detected by a gear 20 attached to the drive shaft 14 of the fuel injection pump 12 and an engine rotation sensor 22 attached to the pump housing 12A. For example, as shown in FIG.
'PA (Pump Angle) For each 45'OA rotation of the engine, the time required for the rotation of 45°CA from the 6th engine to the engine rotational speed NEi (1-
1 to 4), and from the engine rotation speed NE:, the fourth
As shown in the figure, the rotational variation DNED (+1
-1 to 4) is detected, and the average value of this and the rotational fluctuation of the gold cylinder (hereinafter referred to as average rotational fluctuation) WNDLT (=suDN
EP/4) and the rotational fluctuation of the cylinder concerned is compared with the average rotational fluctuation WN D
If it is smaller than L T, it is assumed that there are fewer fuel injection ports in the cylinder, and the difference (hereinafter referred to as rotational fluctuation deviation) DDNEp (p-1 to p-4) is calculated according to, for example, FIG. As shown in , the fuel injection amount that should be increased (hereinafter referred to as the correction amount) Δq is learned and reflected in the next fuel injection of the relevant cylinder. If it is large, it may be possible to reduce the fuel injection amount for the cylinder concerned. In this way,
For example, as shown in Figure 6, until the rotational fluctuations of each cylinder are equalized,
A fuel injection pump actuator, for example, a spill actuator for controlling spill ring in a distribution type fuel injection pump, is controlled for each cylinder to increase or decrease fuel injection 1) In for each cylinder, thereby controlling the fuel injection level between cylinders. Therefore, it is possible to suppress engine vibration. In Figure 6, VScmpD(+) = 1~4)
is a command value for each cylinder, and V3rin is an injection command voltage. In such cylinder-by-cylinder fuel injection amount control, it is necessary to accurately detect the crank angle, which serves as a control reference. Generally, in a 4-cylinder engine, fuel is injected in each cylinder every 180°CA and an explosion occurs, so 45°C
The engine rotational speed for each A is as shown in Figure 6 above.
Draw a waveform with one period of 180" OA. In this periodic waveform, the lowest rotational speed NE1 at 180° CA
The point coincides with the injection timing (top dead center) of a certain cylinder. That is, it is desirable to switch the cylinder discrimination at the lowest rotational speed 1jFNE+. Therefore, conventionally, at this point, the control command value for the injection amount of the next cylinder is switched (updating the injection command voltage V S fin) to compensate for the response delay of the system. However, if the timing of capturing the engine rotational speed NE1 at every 45° CA is shifted due to noise, misfire, instantaneous interruption of the battery power supply, etc., and the position of the lowest rotational speed is shifted,
Switching of the injection command voltage 5fin is performed at the timing of NF2, NEs or NF2, and the cylinder to be corrected is shifted, a response delay occurs, and the cylinder-specific control of the fuel injection II4 amount does not work properly. This has caused problems such as increased idle rotation fluctuations and increased vibrations. [Object of the Invention] The present invention has been made in order to solve the above-mentioned conventional problems, and even if noise, misfire, instantaneous interruption of battery power supply, etc. occur, the timing of cylinder-specific correction and the cylinder to be corrected can be adjusted. It is an object of the present invention to provide a method for controlling cylinder-by-cylinder fuel injection for an electronically controlled diesel engine, which does not remain deviated and can therefore accurately control the fuel injection by cylinder.

[Structure of the invention]

The present invention provides fuel injection for each cylinder of an electronically controlled diesel engine in which the amount of fuel injection is controlled for each cylinder based on the lowest engine rotation speed among a plurality of engine rotation speeds during the explosion of each cylinder. The quantity control method, as summarized in FIG. 7, includes a procedure for determining whether the actual engine rotation speed corresponding to the reference rotation speed is the lowest rotation speed; At this time, the procedure is to continue the cylinder-specific control as it is, and when the rotation speed is not the lowest, the cylinder-specific control is canceled and the cylinder-specific control is newly started based on the engine rotation speed corresponding to the actual minimum rotation speed. The above object is achieved by including a procedure for restarting control.

[Action of the invention] In the present invention, it is determined whether the actual engine rotation speed corresponding to the lowest reference rotation speed among the plurality of engine rotation speeds during the explosion of each cylinder is the lowest rotation speed. When the rotation speed is not the lowest, the cylinder-specific control is canceled and the cylinder-specific control is restarted based on the crank angle corresponding to the actual minimum rotation speed, which reduces noise and misfires. Even if a momentary power outage or the like occurs in the battery power supply, the timing of cylinder-specific correction and the cylinder to be corrected do not remain deviated, and therefore, the cylinder-specific control of the fuel injection amount is performed appropriately. 【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings below, a method for controlling fuel injection amount by cylinder for an electronically controlled diesel engine according to the present invention was adopted. An example of an electronically controlled diesel engine for automobiles will be described in detail. As shown in FIG. 8, this embodiment includes a drive @ 14 that rotates in conjunction with the rotation of the crankshaft of the diesel engine 10, and a feed pump 16 (for pumping fuel) fixed to the drive shaft 14. Figure 8 is 90
'The unfolded state is shown), a fuel pressure adjustment valve 18 for adjusting the fuel supply pressure, and a gear 20 fixed to the drive shaft 14.
an engine rotation sensor 22 made of, for example, an electromagnetic pickup for detecting the rotational part of the diesel engine 10 from the rotational displacement of the engine; a roller ring 25 for driving the pump plunger 24 in cooperation with the face cam 23; a timer piston 26 (FIG. 8 shows the expanded state of 906) for controlling the uneven position of the timer piston 25; a timing control valve 28 for controlling the fuel injection timing by controlling the position of the timer piston 26; A timer position sensor 30, for example, a variable inductance sensor, for detecting the position of the timer piston 26.
, a spill ring 32 for controlling the timing of fuel release from the pump plunger 24, a spill actuator 34 for controlling the fuel injection 14m by controlling the position of the spill ring 32, and a plunger 34A of the spill actuator 34. A spill position sensor 36 consisting of, for example, a variable inductance sensor for detecting the position Vsp of the spill ring 32 from the displacement of the spill ring 32, a fuel cut solenoid (hereinafter referred to as FCV) 38 for cutting fuel when the engine is stopped, and a backflow of fuel. A distribution type fuel injection pump 12 having a delivery valve 42 for preventing the rear runout, and a fuel injection pump 12 for injecting the fuel discharged from the delivery valve 42 of the fuel injection pump 12 into the combustion chamber of the diesel engine 10. An injection nozzle 44, an intake pressure sensor 48 for detecting the pressure of intake air taken in through the intake pipe 46, an intake temperature sensor 50 for also detecting the temperature of the intake air, and a cylinder block of the engine 10. an accelerator sensor 56 for detecting the depression angle (hereinafter referred to as accelerator opening degree) of an accelerator pedal 54 operated by the driver (hereinafter referred to as accelerator opening degree); The accelerator opening Accp is detected from the output of the accelerator sensor 56, the engine rotation speed N E is determined from the output of the engine rotation sensor 22, and the engine cooling water temperature is detected from the output of the water temperature sensor 52. The timing control valve 28 and the spill actuator 3 are controlled so that a controlled injection amount of fuel is injected from the fuel@injection pump 12 at the controlled injection timing.
4, etc., and an electronic control unit (hereinafter referred to as ECU) 58. As shown in detail in FIG. 9, the ECU 38 includes a central processing unit (hereinafter referred to as CPU) 58A consisting of, for example, a microprocessor for performing various calculation processes, a clock 58B for generating various clock signals, and a clock 58B for generating various clock signals. C.P.
(hereinafter referred to as RA, M)
58C and a read-only memory (hereinafter referred to as ROM) 58 for storing control programs, various data, etc.
D, buffer 58, the output of the water temperature sensor 52 which is input via E, the output of the intake air temperature sensor 50 which is input via the buffer 58F, the output of the intake pressure sensor 48 which is input via the buffer 58G, and the buffer. It is driven by the sensor drive frequency signal of the accelerator sensor 56 output inputted via the sensor drive circuit 58H and the sensor drive circuit 58J output, and the spill position sensor 36 output Vsp inputted via the sensor (l detection circuit 58K), A multiplexer (hereinafter referred to as MPX) 58N for sequentially taking in the output of the timer position sensor 30, etc., which is driven by the sensor drive frequency signal output from the drive circuit 58L and input via the sensor signal detection circuit 58M;
An analog-to-digital converter (hereinafter referred to as A/D converter) 58P for converting the analog signal of the X58N output into a digital signal, and the output of the A/D converter 58P is
An input/output boat (hereinafter referred to as 110 boat) 58Q for loading into LJ58A and the engine rotation sensor 22
a waveform shaping circuit 58R for shaping the output of the waveform and directly inputting it into the CPU 58A; a drive circuit 588 for driving the timing control valve 28 according to the calculation result of the CPU 58A; a drive circuit 58 for driving the FCV 38 according to the
T, and the C converted into an analog signal by a digital-to-analog converter (hereinafter referred to as a D/A converter) 58U.
Depending on the deviation between the PtJ58A output and the spill position signal Vsp of the spill position sensor 36 output, the spill actuator 34 is connected to the servo amplifier 58V and drive circuit 58W of the drive layer, and each of the components. ,
"Monbus 58X for transferring commands and data,"
It consists of Hereinafter, the operation of the embodiment will be explained. In this embodiment, periodic inspection of the deviation of the reference rotational speed NE+ is performed according to an engine rotational speed interrupt routine as shown in FIG. 10. That is, first, in step 110, counter 1 (i=1
-4) is incremented. Here, when +=1, the minimum (reference) rotation speed is entered, and when i=3, the maximum rotation speed is entered. Next, the process advances to step 112, and the count value of counter 1 is 5.
Determine whether or not. If the determination result is positive, that is, if it is determined that counter 1 is overflowing, the process proceeds to step 114, where 1 is placed in counter i-. Next, the process proceeds to step 116, where a counter l1l (ll=1 to 4) set corresponding to the cylinder number is incremented. This counter p is 1.180 at 0 to 180° CA.
2 when ~360°CA, 3.360~540°CA, 4 when 540~720'OA, 720°O
A is set to return to 1. Next, the process proceeds to step 118, where it is determined whether the count value of counter 1) is 5 or not. If the judgment result is positive,
That is, for a poem for which it is determined that the counter p has overflowed, the process proceeds to step 120 and 1 is placed in the counter I). After step 120 or step 112.11 above
If the determination result in step 8 is negative, the process proceeds to step 122, where the engine rotational speed I/EI for each 45° CA at that time is calculated and stored in the RAM at address (A+i). Next, the process proceeds to step 124, where it is determined whether the count value of counter 1 is 1 or not. If the judgment result is positive,
That is, when it is determined that 180'CA has elapsed, the process proceeds to step 12G, where the engine rotational speed NE+ per 45°CA at that time is determined as the lowest rotational speed among NE+ to NE4 respectively stored at addresses A+1 to A+4 of the RAM. However, the judgment is reversed. If the determination result is positive, that is,
When it is determined that the actual engine rotation speed corresponding to the reference rotation speed NE+ is the lowest rotation speed, this routine is immediately terminated. On the other hand, if the determination result in step 126 is negative,
That is, when it is determined that the actual engine rotation speed corresponding to the reference rotation speed NE+ is not the lowest rotation speed, and that there is a deviation between the two, the process proceeds to step 128, and the counter C that counts the number of erroneous cylinder detections is executed. Increment. Next, the process proceeds to step 130, and the count value of the counter p is 4.
Determine whether or not. When the determination result is positive, that is, when it is determined that 720° CA has elapsed, the process proceeds to step 132, and it is determined whether the count value of the counter C is 2 or more. This step 132 is performed to prevent the control of the injection amount by cylinder from being reset more than necessary if the control of the injection amount between cylinders is reset due to only one erroneous detection of a cylinder. belongs to. If the determination result in step 132 is positive, that is,
When it is determined that cylinder misdetection has occurred twice or more during 720'OA, the process proceeds to step 134, and the control of the inter-cylinder injection amount is reset. Specifically, the cylinder-specific command 1+m V Scmpρ (p-1 to 4) shown in FIG.
are all set to zero, cancel the cylinder-specific control up to that point, and then set the minimum engine rotation speed aNE+ and start a new cylinder-specific control based on the engine rotation speed corresponding to the newly set actual minimum engine rotation speed. Resume control. After step 134 is completed, or if the determination result in step 132 is negative, the process proceeds to step 136, where the counter C is cleared in preparation for the next abnormality determination, and this routine ends. Further, if the determination result in steps 124 and 130 is negative, this routine is immediately terminated. In this embodiment, if cylinder erroneous detection occurs twice or more during 720' CA, the cylinder-specific control up to that point is reset, so resetting the cylinder-specific control is unnecessary. It is never done. Note that the number of cylinder erroneous detections for which cylinder-specific control should be reset is not limited to this.

【Effect of the invention】

As explained above, according to the present invention, noise, misfire,
If the reference rotation speed capture timing shifts or the correction target cylinder shifts due to a momentary interruption of the battery N source, etc.
Cylinder-specific control is immediately reset. Therefore, the cylinder-specific control of the fuel injection i always operates properly, and there is an excellent effect that the idle rotation fluctuation does not increase and the engine vibration does not increase.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between rotational fluctuations and crank runout undulations in a conventional electronically controlled diesel engine, and Fig. 2 shows the configuration of an engine rotation sensor used in a conventional electronically controlled diesel engine. The cross-sectional view shown in FIG.
A diagram showing how to calculate the correction amount each time, FIG. 6 is a diagram showing examples of signal waveforms of various parts in a conventional example, and FIG. 7 is a diagram showing fuel injection control for each cylinder of an electronically controlled diesel engine according to the present invention. FIG. 8 is a flowchart without showing the gist of the method; FIG. 8 is a sectional view including a partial block diagram showing the overall configuration of an embodiment of an electronically controlled diesel engine for automobiles in which the present invention is adopted;
The figure is a block diagram showing the configuration of the electronic control unit, and FIG. 10 is a block diagram showing the configuration of the electronic control unit. FIG. DESCRIPTION OF SYMBOLS 10... Engine, 12... Fuel injection pump, 22... Engine rotation sensor, 24... Pump plunger, 32... Spill ring, 34... Spill actuator, 36... Spill position sensor , 44... Injection nozzle, 58... Electronic control unit <ECU), NE+...
-45" OA engine rotation speed, DNEI)...Engine rotation variation, WNDLT...Average rotation variation, vs cmpp...Cylinder specific command value, V5fin.
...Injection command voltage. Agent Takaya Ron (and 1 other person)

Claims (1)

[Claims] (1) A fuel injection amount control method for each cylinder of an electronically controlled diesel engine, in which the fuel injection amount is controlled for each cylinder based on the lowest engine rotation speed among multiple engine rotation speeds during the explosion of each cylinder. , a procedure for determining whether the actual engine rotation speed corresponding to the reference rotation speed is the lowest rotation speed or white, and a procedure for continuing cylinder-specific control when the rotation speed is the lowest rotation speed. , when the engine speed is not the minimum rotational speed, stopping the cylinder-specific control up to that point and restarting the cylinder-specific control anew based on the engine rotational speed corresponding to the actual minimum rotational speed; A method for controlling fuel injection amount for each cylinder in an electronically controlled diesel engine.