JPS5885331A - Control method of fuel injection quantity in diesel engine - Google Patents

Abstract

PURPOSE:To control cold start and restart characteristics of a Diesel engine to an optimum condition, by controlling a starting fuel injection quantity through use of a control accelerator opening increased at cold time of the Diesel engine while decreased at warmed time of the engine. CONSTITUTION:When an engine is started further rotated at a speed NE not higher than 800rpm, a control accelerator opening ACCP0 is used in a step 105 to control a fuel injection quantity. In consequence, even if an accelerator is not depressed at starting, quantity insufficiency of fuel is not caused and a start characteristic of the engine is improved. While also at restarting after complete warming, the control accelerator opening ACCP0 is used to control the fuel injection quantity, and a smoke can be decreased without causing the excessiveness of the fuel injection quantity. In this way, cold start and restart characteristics can be controlled to an optimum condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection amount control method for a diesel engine, and more particularly to a fuel injection amount control method for a diesel engine that performs general fuel injection depending on the temperature state of the diesel engine.

In a conventional fuel injection amount control method for electronically controlling fuel injection in a diesel engine, the fuel injection amount is determined according to a fuel injection pattern as shown in FIG. 5, which will be described later. That is, if the accelerator is not depressed at the time of starting, the fuel injection amount pattern is controlled with an accelerator opening of 0. However, the conventional injection amount pattern that varies depending on the actual accelerator opening has the drawback that when the engine is started at a low temperature and the engine speed is low, the amount of fuel F injection becomes insufficient, resulting in poor engine startability. On the other hand, when the engine is restarted after it has completely warmed up, the amount of fuel injected is too large, resulting in smoke. Furthermore, with the conventional injection amount pattern,
As the engine speed increases, the fuel injection amount decreases too quickly.
It has the disadvantage of causing engine stall, especially at low temperatures.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling a fuel injection amount of a diesel engine that has excellent cold startability and restartability of the diesel engine.

The present invention has a fuel injection amount pattern in which the fuel injection amount increases in accordance with an increase in the actual accelerator opening, and an accelerator opening for control used at startup. The cell opening degree is set so that it increases when the engine is cold and decreases when the engine is warmed up, that is, it changes depending on the temperature condition such as the water temperature of the diesel engine, and the actual acceleration depends on the temperature condition when the diesel engine starts. The opening degree refers to the accelerator opening degree on the above-mentioned control, which is used to control the fuel injection amount.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the fuel injection amount control method for a diesel engine according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a fuel injection pump and a control device suitable for applying the present invention.

The fuel injection pump 1 includes a drive shaft 11 driven by an engine, a gear 1.2 and a roller 13 provided at the top of the drive shaft, a cam plate 14 loosely connected to the roller 13, and a cam plate 14 coupled to the plate 14. A pump/plunger 15 for sending fuel to the injection nozzle 2 of the machine, a fuel pump 17 for sending fuel to the injection nozzle 2 and the timer piston 16, and a timer position for electrically detecting the position of the timer piston 16. A sensor 18, a timing control valve 19 that determines advance angle adjustment, and an electromagnetic pickup sensor 20 that outputs a pulse signal according to the rotational speed of the gear 12. pump·
Spill ring 21 that controls the amount of fuel leaking from the spill boat of plunger 15, r;o. A linear solenoid 22 that drives the spill ring 21, a coil 23 that constitutes the linear solenoid 22, a plunger 24 that drives the spill ring 21, a spill position sensor 25 that detects the amount of movement of the plunger 924, and a pump plunger. FCV 26 (consisting of excitation coil 27 and pulp 28) that controls the supply and cut of fuel to 15, and a delivery pulp that adjusts the fuel made to high pressure by pump plunger 15 so that it is smoothly injected from injection nozzle 2. 56 and regulating pulp 29.

The cam plate 14 rotates and reciprocates together with the pump plunger 15. This reciprocating motion is caused by a roller 1 that is rotatable but fixed in the axial direction of the shaft 1.
This occurs when the cam plate 14 rides on the cam plate 3.

Injection timing is given by rotation of pump plunger 15. To adjust the injection amount, use a spill boat with a pump/plunger of 15 injection amounts! ; Determined by the position of the spill ring 21 that controls the amount of fuel leaking from o. Excess fuel in the pump is returned to the boss 17 through the orifice 3°. In addition, the control of the linear solenoid 2 and F (426 in the fuel pump 1 is performed by the control device 3)
For this purpose, output signals from various sensors are captured. That is, the electromagnetic pickup sensor 2o
Engine speed signal sN and spill position sensor 2 by
These are the pump side information and the engine side information of the output signal Ss of No. 5.

Note that the timer position center t18 is used for timing control and is not related to the present invention, so a description thereof will be omitted. Engine side information includes an output signal 8a of the intake temperature sensor 5 provided in the intake manifold 4, and an output signal Sp1 of the intake pressure sensor 6 also provided in the intake manifold 4.
There is an output signal Sw of the water temperature sensor 7 that measures the engine cooling water temperature and an output signal 8ACC of the accelerator sensor 9 that detects the amount of pedal depression of the accelerator 8), but some of this information is also used for air-fuel ratio control. It will be done. -Second
The figure is a detailed block diagram of the control device 3 shown in FIG.・Memory (R, OM) 3
2. A random access memory (RAM) 33 which temporarily stores the calculation contents and the output contents of each sensor, and has a backup memory which continues to store the calculation contents, setting values, etc. even when the power is turned off. 1. A second input/output circuit 34.35 is connected to the CPU 31 via a path line 36, and is also connected to the CPU 31, the input/output circuit 34.35, etc., and has a clock 37 serving as a timing reference for information processing. A so-called microcomputer is configured.

The output devices connected to and controlled by the CPO 31 include the timing control valve 19, the linear solenoid 22, and the F
CV26, timing control valve 19 and F″cv2
6 are driven through each of the drive circuits 38, 39, and the linear solenoid 22 is connected to the 1)/A converter 40. Each of the servo amplifiers 41 is driven by a drive circuit 42 . Note that 1)/A converter 40 uses the clock 3.
7 is connected to the servo amplifier 41, and a spill position sensor g 65 is input to the servo amplifier 41.

The input/output circuit 34 is for receiving the senna output. intake temperature sensor 5, intake pressure sensor 6, water temperature sensor 7,
The output of the accelerator sensor 9 is buffer r43.44.45
．． 46 and sends this output to a multiplexer (
MP, X) After selecting one in sequence or four at 47,
The data is converted into a digital signal by the A/D converter 48 and then output to the pass line 36. Note that the clock 37 is connected to the A/D converter 48. Also, the spill position □
The output of the senna drive circuit 49 is input to the sensor 25,
The detection output of the spill position sensor 25 is input to the multiplexer 47 via the sensor signal detection circuit 50, and the output of the sensor drive circuit 51 is input to the timer position sensor 18. The detection output is input to the multiplexer 47 via the signal detection circuit 52. These detection signals are sequentially selected by m silkworms↓m by the multiplexer 47 and output to the path line 36 through the AID converter 48 and the input/output port 34.

On the other hand, in the input/output circuit 35, a torque converter signal 53, an air conditioner signal 54, and a starter signal 55 are sent to a buffer 56, respectively.
．． 57.58. Furthermore, a rotation speed detector 59 for detecting the engine rotation speed is provided, and its output signal is waveform-shaped by a waveform shaping circuit 60 and then sent to the CPU.
31 and is input to the fail detection circuit 61. The output signal of this fail detection circuit 61 is input to the drive circuit 39. Also, the plus B power supply 62 is the buffer 63,
It is connected to the drive circuit 39, 42 and the fail detection path 61 through the power supply abnormality detection circuit 64.

FIG. 3 shows a flowchart of processes performed by the control device 3 shown in FIG. 1 in order to realize an embodiment of the method for controlling the fuel injection amount of a diesel engine according to the present invention.

First, in step 101 it is determined whether 50 msec has elapsed, and if 9 msec has elapsed, it is determined in step 102 whether or not it is time to start the engine. In the case of starting, it is determined in step 103 whether the engine rotational speed NE is below soorpm, and when it is below 800 rpm+7), step 1 is performed.
At step 05, the control accelerator opening ACPo is calculated using the following formula.゛ACCP o = Kr (40℃-THW)...beating...
・(1) However, 'l'HW represents the water temperature and K1 represents a constant. This equation (1) is as shown in FIG. 4, and the values of AeC and Po increase as the engine water temperature decreases.

If it is determined in step 102 that the engine is not starting, or if in step 103 the engine speed NE is greater than 80 Orpm, ACCPo is set to decrease in step 104. That is, A.C.
It is extracted by calculating CPo=ACCPo-. however,
K is a constant.

AIIIP is newly added in steps 104 and 105.

is determined, or if it is determined in step 101 that 50 msec has not elapsed, in step 106
It is determined whether CCPo is positive or negative, and if it is negative, step 10
At step 7, the process proceeds to step 108 with ACCPo as ochi.

If it is determined in step 106 that A'CCPo is positive, the process immediately proceeds to step 108, where R, AM33 is
Remember CPo. That is, step 101 to step 1
AOCP at the stage up to 07.

is calculated, determined, and stored.

Next, the control accelerator opening ACCP is set using the sleeve 109.
A comparison is made between o and the actual accelerator opening degree ACCP. ACCP (in case of ACCPo, A in step 110)
CCPo is changed to ACCP and the process proceeds to the next step 111. If ACCP)ACσPo, the process proceeds to the next step 111 using the actual accelerator opening degree ACCP. Note that the pattern of the fuel injection amount with respect to the engine rotational speed NE using the actual accelerator opening degree ACCP as a parameter is determined as shown in FIG. However, the solid line in the figure shows the normal fuel injection degree pattern, and the broken line shows the fuel injection amount pattern when performing parallel movement control in the direction of the rotation axis, which will be described later.

Step:)-j In 111, the injection amount pattern shown in Fig. 5 is moved in the rotational axis direction @N according to the engine water temperature, air conditioner, torque converter, and other engine conditions and load conditions.
F(d is displayed. This method of controlling the injection amount pattern by moving it in the direction of the rotation axis is used to perform fast idle control, air conditioner idle up, and other controls, and is already a well-known method. Note that Fig. 6 shows a characteristic diagram of the amount of movement in the rotational axis direction NF(P) with respect to the engine water temperature.In step 112, the value obtained by calculating the above-mentioned NF'(P) from the engine rotational speed NE is calculated as NEl.
shall be. Next, in step 113, NE' shown in FIG.
From the fuel injection amount map showing the relationship between the fuel injection amount and the accelerator opening ACCP, the basic injection amount QBASEft is determined to be 1.However, here, ACCP used in step 113 is determined by the ALI-) determined in steps 101 to 110.
'.

There is a place where is used. This is the feature of this embodiment. That is, for example, when the engine is started and the engine speed is low, the accelerator opening ACCP is controlled.

is used, and the opening degree is larger and the injection amount is larger than when completely warmed up (ACCPo=01).

Next, in step 114, it is determined whether QBASE is greater than or equal to a set value. If QBASE is less than the set value (maximum injection amount), the final injection is made to be tQFIN=QpsE, and the upper limit of QBASE is set as the maximum injection amount.

In step 115, the final injection amount QFI shown in FIG.
The amount of injected fuel is controlled by changing the spill position from the map of N and engine rotational speed [NE].

According to this embodiment, when the engine is started and the engine/engine rotation speed NE is 800. When the engine temperature is below rpm, the engine temperature is lower and the problem becomes larger. In addition, even when the engine speed is low, the amount of fuel injected to the engine will not be insufficient even if the accelerator is not pressed at the time of starting, which has the effect of improving engine startability, and there is no need to press the accelerator. This has the effect of simplifying operability. In addition, even when restarting the engine after it has been completely warmed up, the fuel injection amount is controlled using the accelerator opening ACCPo, which is controlled to reduce the opening when the engine temperature is high. It has the effect of reducing smoke without being too much. Furthermore, when the engine speed NE increases, the accelerator opening is controlled to decrease by subtracting a constant from the controlled accelerator opening, which has a large opening at low temperatures, so the fuel injection amount decreases at low temperatures. Since the speed is slow, it has the effect of preventing engine stall at low temperatures.

As described above, according to the diesel engine fuel injection amount control method of the present invention, it is possible to provide a diesel engine fuel injection amount control method that provides excellent cold startability and restartability of the diesel engine.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a fuel injection pump and peripheral devices to which the present invention is applied, FIG. 2 is a detailed block diagram of the control device f3 in FIG. 1, and FIG. 3 is a fuel injection amount control of a diesel engine according to the present invention. In order to realize one example of the method, FIG. 4 is a flowchart processed by the control device 3, and FIG.
The figure is a fuel injection amount pattern diagram showing the relationship between the fuel injection amount and the engine rotation speed, Figure 6 is a characteristic diagram of the rotational axis direction movement amount N F (P) with respect to the engine water temperature, and Figure 7 is the engine rotation speed NE Basic injection tQBAsE map diagram determined by the relationship between ' and accelerator opening ACCP, Figure 8 shows the engine rotation speed NE and final injection! (QF'IN
Spill position command voltage vspp determined by the relationship with
It is a map diagram. 1...Fuel injection pump, 3...Control device, 5...
Intake temperature sensor, 6... Intake pressure sensor, 7... Water temperature sensor, 9... Accelerator/Set, 18... Timer position sensor, 719... Timing control valve, 21...
Spill ring, 22... Linear solenoid, 23...
・Coil, 24... Plunger, 25... Spill position sensor, 26... Fuel control valve (FCV), 27...
・Excitation coil, 28...mu access memory (RA
M), 34.35...Input/output circuit, 36...Pass line, 38.39.42...Drive circuit, 40...D
/A converter, 41... Servo amplifier, 43 to 46.5
6~58.63...Buffer, 47...Multiplexer (MPX), 48...A/Dr meter, 5...Single sensor, 59...Rotation speed detector, 60...・
・Waveform shaping circuit, 6:1. ...Fail detection circuit. 3171 Fig. 4・Fig. 51・I E /G U3 rotation 68 N (XIO”rpm) Fig. 6 FS 71++ Same rotation wheel Hiroshi NE (XIO2rpm) Fig. 8

Claims (1)

[Claims] A diesel engine that electronically controls the amount of fuel that is supplied to the diesel engine installed in Toga in a spray state via a fuel control valve using a fuel injection amount pattern that is determined using the actual accelerator opening as a parameter. In the fuel injection amount control method, a control accelerator opening degree that increases when the diesel engine is cold and decreases when it warms up is provided, and the actual accelerator opening degree is different from the actual accelerator opening degree depending on the temperature state at the time of starting the diesel engine. A fuel injection amount control method for a diesel engine, characterized in that the fuel injection amount is controlled using a control accelerator opening degree.