JPH0361013B2 - - Google Patents

Description

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

The present invention relates to a fuel injection amount control method for a diesel engine, and particularly to a method for controlling an engine operating state including an accelerator opening degree and an engine rotation speed, which is suitable for use in an automobile diesel engine equipped with an electronically controlled fuel injection device. The present invention relates to an improvement in a fuel injection amount control method for a diesel engine, which determines the fuel injection amount accordingly.

[Prior Art] Generally, in a diesel engine, fuel supplied to its combustion chamber is controlled by a fuel injection pump that is driven to rotate in synchronization with engine rotation. By operating a timer and moving a roller ring using the supply pressure of the provided feed pump, the fuel injection timing is controlled, and by moving a spill ring using a centrifugal governor to change the end of pumping, The fuel injection amount is controlled. However, in the past, both the timer and the spill ring were mechanically controlled, making it difficult to precisely control the fuel injection amount. On the other hand, in recent years, with the development of electronic control technology, especially digital control technology, attempts have been made to electronically control the fuel injection amount of diesel engines. In such electronic control, the fuel injection amount is generally determined according to the engine operating condition, including the accelerator opening degree determined from the output of the accelerator sensor and the engine rotation speed. During sudden acceleration or sudden deceleration when the accelerator pedal is released all at once, the output of the accelerator sensor changes rapidly, so the required accelerator opening also changes rapidly, which causes a sudden change in the amount of fuel injection, causing the engine to The generated torque changes rapidly. Therefore, large acceleration/deceleration shocks occur, which may cause discomfort to occupants of vehicles equipped with diesel engines. In order to solve the above-mentioned problems, for example, as shown in Japanese Patent Application Laid-Open No. 57-28829, there is a method of reducing deceleration shock during engine braking by reducing the amount of fuel injection during sudden deceleration. Proposed. According to this method, it is possible to obtain the effect that deceleration shock during sudden deceleration can be reduced to some extent.

[Problem to be achieved by the invention]

However, even with this method, it is not possible to reduce the acceleration shock during sudden acceleration, and the fuel injection amount itself is blunted, so the pattern of the fuel injection amount is always smoothed at the same rate during deceleration. This resulted in a disadvantage in terms of responsiveness. The present invention has been made in order to solve the above-mentioned problems of the conventional art. An object of the present invention is to provide a fuel injection amount control method for a diesel engine that can effectively reduce the fuel injection amount.

【composition】

The present invention provides a fuel injection amount control method for a diesel engine in which the amount of fuel injection is determined according to engine operating conditions including the accelerator opening degree and engine rotational speed, in which the amount of change in the accelerator opening degree is less than or equal to a predetermined value. A sudden acceleration and/or sudden deceleration is detected, and when the accelerator opening is captured, at the time of sudden acceleration or sudden deceleration, the amount of change in the accelerator opening is controlled at a predetermined upper limit value to perform smoothing processing. The above objective is achieved by determining the fuel injection amount using the accelerator opening after smoothing.

[Effect]

The present invention was made based on the discovery that reduction in acceleration due to sudden operation of the accelerator pedal during sudden acceleration and/or sudden deceleration becomes a particular problem when acceleration and/or deceleration exceeds a certain amount. It is something. Therefore, the present invention is configured to reduce acceleration/deceleration shock when acceleration and/or deceleration exceeds a certain specific amount. Further, in the present invention, in order to reduce acceleration/deceleration shock during acceleration and/or deceleration, the amount of change in accelerator opening is limited to a predetermined upper limit value to perform smoothing processing. Such annealing process of the present invention is unnecessary compared to, for example, a method of uniformly delaying an electric signal (a signal according to the accelerator opening degree, etc.) by a predetermined time constant using a resistor R and a capacitor C. This method is excellent in that acceleration/deceleration shock can be reliably eliminated without causing any deterioration in acceleration performance. That is, according to the present invention, sudden acceleration exceeding a certain amount, which causes problems with acceleration/deceleration shock, and
Alternatively, the degree of acceleration or deceleration can be reduced only during sudden deceleration. Therefore, unnecessary deterioration of acceleration performance, etc. does not occur. Furthermore, even when the amount of change in the accelerator opening is larger, the amount of change in the accelerator opening is limited to a predetermined upper limit value, and acceleration/deceleration shock does not occur. In addition, since the present invention performs the smoothing process when the accelerator opening is taken in, the degree of smoothing of the fuel injection amount differs depending on the driving range, which is advantageous in terms of responsiveness. There is also.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electronically controlled fuel injection device for a diesel engine for automobiles will be described in detail with reference to the drawings, in which a method for controlling a fuel injection amount for a diesel engine according to the present invention is adopted. This embodiment includes a drive shaft 14 that rotates in conjunction with the rotation of the output shaft of a diesel engine 10, and a feed pump 16 (for pumping fuel) fixed to the drive shaft 14, as shown in FIG. Figure 2 is
), the fuel pressure regulating valve 18 for adjusting the fuel supply pressure, and the rotational displacement of the gear 20 fixed to the drive shaft 14 cause the drive shaft 14 to rotate by a predetermined crank angle. A rotation speed sensor 22 made of, for example, an electromagnetic pickup for measuring the required time and detecting the rotation speed of the diesel engine 10, a roller ring 24 for controlling fuel injection timing, and a timer for driving the roller ring 24. A piston 26, a timing control valve 28 for controlling the position of the timer piston 26, a timer position sensor 30 consisting of, for example, a variable inductance sensor for detecting the position of the timer piston 26, and a timer position sensor 30 for controlling the fuel injection amount. spill ring 32, the spill ring 32
A spill actuator 34 consisting of a plunger 34a, a compression spring 34b, a coil 34c and a coil case 34d for driving the plunger 34, and a variable inductance sensor for detecting the position of the spill ring 32 from the displacement of the plunger 34, for example. a spill position sensor 36, a fuel cut solenoid (hereinafter referred to as FCV) 38 for cutting fuel when the engine is stopped, and a plunger 4.
0 and a delivery valve 42, an injection nozzle 44 for injecting fuel discharged from the delivery valve 42 of the fuel injection pump 12 into the auxiliary fuel chamber of the diesel engine 10, and an intake pipe 46. An intake pressure sensor 48 for detecting the pressure of intake air taken in through the engine, an intake air temperature sensor 50 for similarly detecting the temperature of the intake air, and an intake temperature sensor 50 disposed on the cylinder block 10a of the diesel engine 10. Cooling water temperature sensor 52 for detecting engine cooling water temperature
, an accelerator sensor 56 for detecting the depression angle of the accelerator pedal 54 operated by the driver (hereinafter referred to as the accelerator opening degree), an accelerator opening degree detected from the output of the accelerator sensor 56, and the rotation speed sensor 22. The target injection timing and calculated injection amount are determined based on the engine rotational speed detected from the output, the engine cooling water temperature detected from the output of the cooling water temperature sensor 52, etc., and the calculated injection amount of fuel is injected from the fuel injection pump 12 at the target injection timing. In a fuel injection amount control device for an automobile diesel engine 10, the fuel injection amount control device includes an electronic control unit (hereinafter referred to as ECU) 58 that controls the timing control valve 28, spill actuator 34, etc. so that fuel is injected. In the ECU 58, during sudden acceleration and sudden deceleration when the amount of change in the accelerator opening is greater than a predetermined value, a smoothing process is performed when the accelerator opening is captured;
The calculated injection amount is calculated using the accelerator opening degree after smoothing. In the figure, 25 is a cam plate, and 33 is a tension spring. The ECU 58, as shown in detail in FIG.
A central processing unit (hereinafter referred to as
(referred to as CPU) 59, the output of the cooling water temperature sensor 52 which is input via a buffer 60, and the intake temperature sensor 50 which is input via a buffer 62.
output, the output of the intake pressure sensor 48 inputted via the buffer 64, the output of the accelerator sensor 56 inputted via the buffer 66, and the sensor drive frequency signal of the sensor drive circuit 68 output, and the sensor signal The timer position sensor 30 is driven by the output of the spill position sensor 36 inputted via the detection circuit 70 and the sensor drive frequency signal outputted from the sensor drive circuit 72, and inputted via the sensor signal detection circuit 74. A multiplexer 76 for sequentially taking in the output etc., an analog-to-digital converter (hereinafter referred to as an A/D converter) 78 for converting the analog signal output from the multiplexer 76 into a digital signal, and the A/D converter 78 for converting the analog signal output from the multiplexer 76 into a digital signal.
an input/output port 80 for inputting the output of the D converter 78 into the CPU 59; a waveform shaping circuit 94 for shaping the output of the rotational speed sensor 22 and inputting it into the CPU 59; and a clock generation circuit 102.
A random accelerator memory (hereinafter referred to as RAM) 104 including a backup random accelerator memory (hereinafter referred to as backup RAM) for temporarily storing calculation data etc. in the CPU 59 and which is backed up in the event of a power failure; Read-only memory (hereinafter referred to as ROM) 1 for storing various data, etc.
06, a drive circuit 108 for driving the timing control valve 28 according to the calculation result in the CPU 59, a drive circuit 109 for driving the FCV 38 in accordance with the calculation result in the CPU 59, and a digital-analog circuit. Depending on the deviation between the output of the CPU 59 converted into an analog signal by a converter (hereinafter referred to as a D/A converter) 110 and the output of the spill position sensor 36,
It is comprised of a servo amplifier 112 and a drive circuit 114 for driving the spill actuator 34. The action will be explained below. Calculation of the fuel injection amount in this embodiment is performed according to a flowchart as shown in FIG. That is, in the CPU 59 of the ECU 58,
First, in step 1010, the accelerator sensor 56
The engine rotation speed NE determined from the output and the output of the rotation speed sensor 22 is taken. Next, the process proceeds to step 1020, by converting the output of the accelerator sensor 56, the accelerator opening degree for control is determined.
Find Accp(i). Then proceed to step 1030,
It is determined whether the current accelerator opening Accp(i) obtained in step 1020 is greater than or equal to the accelerator opening Accp(i- ₁ ) used to calculate the previous fuel injection amount. If the determination result is positive, that is,
When it is determined that the vehicle is accelerating or traveling at a constant speed, the process proceeds to step 1040, where the previous accelerator opening Accp(i- ₁ ) is calculated by adding a predetermined value α to the acceleration smoothing opening, as shown in the following equation. The degree Accp ⁺ (i- ₁ ) is assumed. Accp ⁺ (i- ₁ )←Accp(i- ₁ )+α...(1) Next, proceed to step 1050, and proceed to step 1020 mentioned above.
The current accelerator opening Accp(i) found in step 1040 is the acceleration smoothing opening found in step 1040.
It is determined whether it is greater than or equal to Accp ⁺ (i- ₁ ). If the determination result is positive, that is, if it is determined that the situation is a sudden acceleration in which the amount of increase in the accelerator opening is equal to or greater than a predetermined value, the process proceeds to step 1060, where the acceleration smoothing opening is calculated as Accp ⁺ (i− ₁ ). The current accelerator opening Accp(i)
shall be. On the other hand, if the judgment result in step 1030 is negative, that is, if it is judged that the current state is deceleration, the process proceeds to step 1070, and as shown in the following equation, from the previous accelerator opening degree Accp(i- ₁ ) The value obtained by subtracting the predetermined value α is set as the deceleration smoothing opening degree Accp ^- (i- ₁ ). Accp ^- (i- ₁ )←Accp(i- ₁ )-α...(2) Next, proceed to step 1080, and step 1020
The current accelerator opening Accp(i) found in step 1070 is the deceleration smoothing opening Accp ^-
(i- ₁ ) or more is determined. If the determination result is negative, that is, if it is determined that the deceleration is occurring at a sudden deceleration where the amount of decrease in the accelerator opening is greater than or equal to a predetermined value, the process proceeds to step 1090, and the deceleration smoothing opening is determined.
Let Accp ^- (i- ₁ ) be the current accelerator opening Accp(i). After completing step 1060 or 1090, or
If the judgment result in step 1050 is negative, or if the judgment result in step 1080 is positive, the process proceeds to step 1100, where the current accelerator opening Accp(i) at that time is used for control purposes. It is stored as the accelerator opening degree. In this step 1100, what is stored as the current accelerator opening Accp(i) is the acceleration smoothing opening Accp ⁺ (i- ₁ ) during sudden acceleration, and the deceleration smoothing opening Accp ^- (i- _{1 )} during sudden deceleration. ), otherwise the value of the current accelerator opening Accp(i) obtained in step 1020 above remains unchanged. Next, proceed to step 1110, and proceed to step 1100 mentioned above.
The fuel injection amount (calculated injection amount) is calculated according to the engine operating state including the current accelerator opening Accp(i) stored in and the engine rotation speed, and this routine ends. In this embodiment, the acceleration annealing opening degree Accp ⁺
(i- ₁ ) and the deceleration annealed opening degree ^Accp- (i- ₁ ) because the same predetermined value α is used, so the control program is relatively simple. In the above embodiments, the present invention was applied to both sudden acceleration and sudden deceleration, but it is also possible to apply the present invention only to either sudden acceleration or sudden deceleration. In the above embodiments, the present invention was applied to an automobile diesel engine equipped with an electronically controlled fuel injection device, but the scope of application of the present invention is not limited thereto, and is applied to a general automobile diesel engine equipped with another fuel injection device. It is clear that the same applies to diesel engines.

【Effect of the invention】

As explained above, according to the present invention, a sudden change in the engine generated torque due to a sudden operation of the accelerator pedal during sudden acceleration and/or sudden deceleration is prevented, and therefore a vehicle equipped with a diesel engine Acceleration/deceleration shock is reduced, and a smooth acceleration/deceleration feeling can be obtained. or,
Since the smoothing process is performed when the accelerator opening is taken in, the degree of smoothing of the fuel injection amount differs depending on the driving range, which has excellent effects such as being advantageous in terms of responsiveness. .

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the gist of the fuel injection amount control method for a diesel engine according to the present invention, and FIG. FIG. 3 is a sectional view including a partial block diagram showing the configuration of an embodiment of the electronically controlled fuel injection device; FIG. 4 is a block diagram showing the configuration of the electronic control unit used in the embodiment. 1 is a flow chart showing a routine for calculating the fuel injection amount. 10... Diesel engine, 12... Fuel injection pump, 22... Rotational speed sensor, 44... Injection nozzle, 54... Accelerator pedal, 56... Accelerator sensor, 58... Electronic control unit (ECU).

Claims (1)

[Claims] 1. A diesel engine fuel injection amount control method in which the fuel injection amount is determined according to engine operating conditions including an accelerator opening and an engine rotational speed, wherein the amount of change in the accelerator opening is a predetermined value. The above sudden acceleration and/or sudden deceleration is detected, and when the accelerator opening is taken in, the amount of change in the accelerator opening is controlled at a predetermined upper limit value during the sudden acceleration or sudden deceleration. A fuel injection amount control method for a diesel engine, characterized in that the fuel injection amount is determined by performing a smoothing process and using the accelerator opening degree after the smoothing.