JPH0465222B2 - - Google Patents

Description

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

The present invention relates to a fuel injection amount smoothing control method for a diesel engine, and is particularly suitable for use in an electronically controlled diesel engine for automobiles equipped with a manual transmission, and is suitable for engine operation including engine rotation speed with accelerator opening. When determining the fuel injection amount according to the situation, the accelerator opening and fuel injection amount are smoothed during deceleration to prevent sudden decreases in the accelerator opening and fuel injection amount and reduce the deceleration of engine rotation. The present invention relates to an improvement in a fuel injection amount smoothing control method for a diesel engine.

[Conventional technology]

Generally, in a diesel engine, cylinder surface pressure is high due to high compression, and mechanical loss due to friction and the like is large. Therefore, when decelerating by fully closing the accelerator pedal, engine braking is applied more strongly than with a gasoline engine, and in particular, fuel is cut when the accelerator pedal is fully closed at a predetermined engine speed or higher. In a diesel engine equipped with this function, the negative torque generated by the engine brake is large, so the traveling speed of the vehicle is rapidly reduced, and the deceleration is so large that there is a risk that the occupants may feel uncomfortable. In order to solve such problems, for example, as shown in Japanese Patent Application Laid-Open No. 57-28829, the speed at which the amount of fuel injection decreases (for example, the amount of decrease for each fuel injection) during sudden deceleration is improved.
It has been proposed to perform a so-called smoothing process by limiting the value to a predetermined limit value or less, thereby reducing deceleration shock particularly during engine braking.

[Problems to be solved by the invention]

However, if the above-mentioned smoothing process is always performed during deceleration in a diesel engine installed in a vehicle equipped with a manual transmission,
There is a problem in that when the clutch is disengaged and the engine becomes unloaded, the amount of fuel injected becomes excessive and the engine rotation speed increases unnecessarily. The present invention has been made in order to solve the above-mentioned conventional problems, and provides a fuel injection amount smoothing control method for a diesel engine that can prevent unnecessary revving of the engine when the clutch is disengaged. The purpose is to

[Means to solve the problem]

The present invention is designed to reduce deceleration by smoothing the accelerator opening and fuel injection amount during deceleration when determining the fuel injection amount according to the engine operating state including the accelerator opening and engine rotational speed. In the fuel injection amount smoothing control method for a diesel engine, as shown in Fig. 1,
A procedure for detecting that deceleration is occurring, a procedure for detecting that the clutch is engaged, and a procedure for detecting that the clutch is engaged while decelerating and the accelerator opening and fuel injection amount are The procedure is to perform normal annealing processing where the reduction speed is small and the allowable deceleration is small, and when deceleration is in progress and the clutch is not engaged, the annealing processing is stopped and the accelerator opening and By including a step of permitting a sudden decrease in the fuel injection amount, or performing annealing processing in which the accelerator opening degree and the fuel injection amount are reduced at a faster rate than the normal annealing process, and the allowable deceleration is large. , the above objective has been achieved.

[Effect]

In the present invention, even during deceleration, if the clutch is not engaged, the smoothing process is stopped and the accelerator opening and fuel injection amount are allowed to suddenly decrease, or the normal process is performed. Since the smoothing process reduces the accelerator opening and fuel injection amount at a faster rate than the smoothing process, and has a larger allowable deceleration, it prevents unnecessary engine speed spikes when the clutch is released. .

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electronically controlled automobile diesel engine equipped with a manual transmission, in which a fuel injection amount smoothing control method for a diesel engine according to the present invention is adopted, will be described in detail with reference to the drawings. As shown in FIG. 2, the first embodiment of the present invention includes a drive shaft 14 that rotates in conjunction with the rotation of the output shaft of a diesel engine 10, and a drive shaft fixed to the drive shaft 14 for pumping fuel. feed pump 16
(Figure 2 shows the state rotated by 90 degrees), a fuel pressure adjustment valve 18 for adjusting the fuel supply pressure, and the drive shaft 1.
4, the rotation speed of the diesel engine 10 is detected by measuring the time required for the drive shaft 14 to rotate by a predetermined crank angle from the rotational position of the gear 20 fixed to the gear 20. A speed sensor 22, a roller ring 24 for controlling fuel injection timing, a timer piston 26 for driving the roller ring 24,
A timing control valve 28 for controlling the position of the timer piston 26, a timer position sensor 30 made of, for example, a variable inductance sensor for detecting the position of the timer piston 26, and a spill ring 32 for controlling the fuel injection amount. , a plunger 34 for driving the spill ring 32
a, a spill actuator 34 consisting of a compression spring 34b, a coil 34c and a coil case 34d;
a spill position sensor 36 made of, for example, a variable inductance sensor for detecting the position of the spill ring 32 from the displacement of the plunger 34;
a fuel cut solenoid (hereinafter referred to as FCV) 38 for cutting fuel when the engine is stopped;
A fuel injection pump 12 having a plunger 40 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 combustion chamber of the diesel engine 10, and an intake pipe. An intake pressure sensor 48 for detecting the pressure of intake air taken in through 46, an intake temperature sensor 50 for similarly detecting the temperature of the intake air, and an intake air temperature sensor 50 disposed in the cylinder block 10a of the diesel engine 10. , a water temperature sensor 52 for detecting engine cooling water temperature, and an accelerator pedal 54 operated by the driver.
an accelerator sensor 55 for detecting the depression angle (hereinafter referred to as accelerator opening degree); and a clutch switch 57 for detecting the disengagement state of the clutch from the operating state of the clutch pedal 56, which is also operated by the driver. The target injection timing and calculated injection amount are determined based on the accelerator opening degree detected from the output of the accelerator sensor 55, the engine rotational speed detected from the output of the rotational speed sensor 22, etc., and the target injection timing is calculated from the fuel injection pump 12. An electronic control unit (hereinafter referred to as ECU) 58 controls the timing control valve 28, spill actuator 34, etc. so that the injection amount of fuel is injected.
It is composed of and. 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 hot water sensor 52 output inputted via a buffer 60, and a buffer 60.
2, the output of the intake pressure sensor 48 is input via a buffer 64, the output of the accelerator sensor 56 is input via a buffer 66, and the sensor drive circuit 68 output is input via a buffer 66. The output of the spill position sensor 36 is driven by a driving frequency signal and is input via the sensor signal detection circuit 70, and the sensor signal detection circuit is also driven by a sensor driving frequency signal output from the sensor driving circuit 72. a multiplexer 76 for sequentially taking in the output of the timer position sensor 30, etc. inputted through the multiplexer 74; and an analog-to-digital converter (hereinafter referred to as A/D) for converting the analog signal output from the multiplexer 76 into a digital signal (referred to as a converter) 78, an input/output port 80 for inputting the output of the A/D converter 78 to the CPU 59, and an input/output port for inputting the output of the clutch switch 57 inputted via a buffer 82. 84, a waveform shaping circuit 94 for waveform shaping the output of the rotational speed sensor 22 and inputting it into the CPU 59, and a clock generation circuit 102.
Random access memory (hereinafter referred to as RAM) 10 including a backup random access memory for temporarily storing calculation data etc. in the CPU 59 and backed up in the event of a power failure
4, a read-only memory (hereinafter referred to as ROM) 106 for storing control programs and various data, etc., and a drive circuit 108 for driving the timing control valve 28 according to the calculation results in the CPU 59. Same as above CPU59
a drive circuit 109 for driving the FCV 38 according to the calculation result in , and a digital-to-analog converter (hereinafter referred to as a D/A converter) 110
The CPU 59 is converted into an analog signal by
a servo amplifier 112 and a drive circuit 114 for driving the spill actuator 34 according to the deviation between the output and the output of the spill position sensor 36;
It is composed of. The effects of the embodiment will be explained below. The accelerator opening degree smoothing process in this embodiment is executed according to the flowchart shown in FIG. That is, in step 110 of the accelerator opening calculation routine for calculating the control accelerator opening based on the actual accelerator opening detected by the accelerator sensor 55, for example, since the accelerator opening is decreasing, , determine whether or not the vehicle is decelerating. If the determination result is positive, the process advances to step 112 and the clutch switch 57 is
Whether the clutch is on or not, depending on the output of
That is, it is determined whether the clutch is engaged or not. If the determination result is positive, that is, it is determined that the clutch is engaged and there is no risk of the engine speed rising unnecessarily even if a small normal annealing process is performed during the permissible deceleration, step 11 is performed.
Proceed to step 4 and perform the normal annealing process, that is, match the allowable deceleration from the previous accelerator opening.
The control accelerator opening degree is determined by subtracting a relatively small predetermined amount, and this routine ends. In this case, the control accelerator opening is larger than the actual accelerator opening, so the fuel injection amount calculated based on the control accelerator opening (and engine speed) also corresponds to the actual accelerator opening. This prevents a sudden decrease in the fuel injection amount. On the other hand, if the judgment result in step 110 is negative and it is determined that the engine is not decelerating, or if the judgment result in step 112 is negative and the smoothing process is performed, the engine speed will be unnecessarily increased. When it is determined that there is a possibility that the accelerator opening may increase, this routine is ended without performing the smoothing process, that is, using the actual accelerator opening as it is for the control accelerator. In this case, the fuel injection amount becomes a value corresponding to the actual accelerator opening, the fuel injection amount decreases rapidly, and the engine speed is prevented from racing up. After the accelerator opening degree calculation routine shown in FIG. 4 is completed, a calculated injection amount is determined according to the control accelerator opening degree, engine rotational speed, etc. in a known fuel injection amount calculation routine. In this embodiment, the smoothing process is stopped when the clutch is not engaged even during deceleration, so the process is relatively simple. Next, a second embodiment of the present invention will be described in detail. This embodiment includes a fuel injection pump 12, a rotational speed sensor 22, an injection nozzle 44, an intake pressure sensor 48, an intake air temperature sensor 50, a water temperature sensor 52, and an accelerator sensor 5, which are similar to the first embodiment.
5. In an electronically controlled automobile diesel engine equipped with a manual transmission, which includes a clutch switch 57, an ECU 58, etc., smoothing processing is performed in the ECU 58 according to the flowchart shown in FIG. It is something. That is, in this example, as shown in FIG.
In the accelerator opening calculation routine similar to the first embodiment shown in FIG. 4, step 112 is performed.
If the determination result is negative, step 210
Then, the process proceeds to step 114 to perform a smoothing process in which the allowable deceleration is three times faster than the normal smoothing process performed in step 114. Other points are
Since this is the same as the first embodiment, the explanation will be omitted. In this embodiment, when decelerating, the smoothing process is performed even when the clutch is not engaged, so that an appropriate deceleration that matches the driver's senses can be obtained. be able to. In each of the above embodiments, the smoothing process according to the present invention was performed on the accelerator opening degree, but the target on which the smoothing process according to the present invention is applied is not limited to this, for example, on the fuel injection amount. It is also possible to perform smoothing processing on itself. In this case, when performing the annealing process with a small allowable deceleration, the limit value for the amount of fuel decrease per fuel injection is set to a small value, and when performing an annealing process where the allowable deceleration is large, the limit value for the amount of fuel decrease per fuel injection is set to a small value. Enlarge. Furthermore, when canceling the smoothing process, the fuel injection amount determined based on the engine load is directly injected without limiting the fuel reduction amount for each fuel injection. In the above embodiments, the present invention was applied to an electronically controlled diesel engine for automobiles, but it is clear that the scope of application of the present invention is not limited thereto, and can be similarly applied to general diesel engines. be.

【Effect of the invention】

As explained above, according to the present invention, unnecessary engine speed increase when the clutch is disengaged is prevented. Therefore, it has the excellent effect of reducing fuel consumption without making the driver feel uneasy.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the gist of a fuel injection amount smoothing control method for a diesel engine according to the present invention;
FIG. 2 is a cross-sectional view, including a partial block diagram, showing the configuration of an embodiment of an electronically controlled diesel engine for an automobile equipped with a manual transmission, in which the present invention is adopted, and FIG. FIG. 4 is a block diagram showing the configuration of the electronic control unit used in the example, and FIG. 4 is a flowchart showing the main part of the routine for calculating the accelerator opening for control. 12 is a flowchart showing a main part of a routine for calculating the control accelerator opening degree, which is used in the second embodiment of the fuel injection amount smoothing control method for a diesel engine according to the present invention. 10... Diesel engine, 12... Fuel injection pump, 22... Rotational speed sensor, 44... Injection nozzle, 55... Accelerator sensor, 57... Clutch switch, 58... Electronic control unit (ECU).

Claims (1)

[Scope of Claims] 1. When determining the fuel injection amount according to the engine operating state including the accelerator opening degree and the engine rotation speed, the accelerator opening degree and the fuel injection amount are smoothed during deceleration, and the accelerator opening degree and the fuel injection amount are smoothed. In a diesel engine fuel injection amount smoothing control method that prevents sudden decreases in engine speed and fuel injection amount and reduces engine rotational deceleration, there is a procedure for detecting deceleration and a process for detecting deceleration. When the engine is decelerating and the clutch is engaged, the rate of decrease in accelerator opening and fuel injection amount is small, and the normal smoothing process is performed with a small allowable deceleration. If the engine is decelerating and the clutch is not engaged, either cancel the annealing process and allow a sudden decrease in the accelerator opening or fuel injection amount, or use the normal procedure described above. A fuel injection amount smoothing control method for a diesel engine, comprising: a step of performing smoothing processing in which an accelerator opening degree and a fuel injection amount are reduced at a faster rate than in a smoothing process, and a permissible deceleration is large.