JPH0575907B2 - - 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 in particular, engine operation including engine rotation speed and accelerator opening, suitable for use in an electronically controlled diesel engine for automobiles equipped with a manual transmission. Improvement of a fuel injection amount smoothing control method for a diesel engine in which the fuel injection amount or accelerator opening is smoothed during acceleration and deceleration to reduce acceleration and deceleration when determining the fuel injection amount according to the state. Regarding.

[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, so-called smoothing processing is carried out by limiting the rate of decrease of the fuel injection amount to a predetermined limit value or less during sudden deceleration. It has been proposed to reduce deceleration shock, especially during engine braking.

[Problems to be solved by the invention]

However, the deceleration shock varies depending on the engine rotational speed, the traveling speed of the vehicle, and the shift position of the manual transmission, and it has been difficult to effectively prevent the deceleration shock in all driving ranges.
Also, if you perform so-called guard processing, which temporarily stops the fuel injection amount at a certain level during smoothing processing or deceleration, and then gradually decreases the fuel injection amount from there, it is especially important for diesel engines equipped with an intake throttle to control the amount of intake air. White smoke was sometimes generated in the engine. The present invention has been made in order to solve the above-mentioned conventional problems, and performs highly accurate control that is well adapted to the vehicle condition to effectively reduce shocks during acceleration and deceleration over a wide driving range. It is an object of the present invention to provide a fuel injection amount smoothing control method for a diesel engine that can prevent the generation of white smoke.

[Means to solve the problem]

The present invention reduces the acceleration/deceleration by smoothing the fuel injection amount or the accelerator opening during acceleration/deceleration when determining the fuel injection amount according to engine operating conditions including engine rotational speed and accelerator opening. In the fuel injection amount smoothing control method for a diesel engine, the fuel injection amount or the accelerator opening is adjusted according to at least one of the engine cooling water temperature, the vehicle running speed, the engine rotation speed, and the amount of change in the accelerator opening. procedure for determining the allowable amount of change in fuel injection amount or accelerator opening from engine speed, accelerator opening, etc., procedure for determining whether acceleration is being performed, and when accelerating. is the fuel injection amount or accelerator opening,
A procedure for increasing the permissible change amount so as to gradually approach the target value; a step for determining that deceleration is in progress; The above objective is achieved by including a procedure of gradually decreasing the target value so as to gradually approach the target value. Further, in an embodiment of the present invention, the allowable change amount of the fuel injection amount or the accelerator opening degree is set according to the allowable change amount depending on the engine cooling water temperature, the allowable change amount depending on the traveling speed of the vehicle, and the allowable change amount depending on the engine rotation speed. By setting the maximum value of the permissible change amount, even when the permissible change amount is determined from a large number of parameters, an appropriate permissible change amount can be selected. Furthermore, in another embodiment of the present invention, when the engine cooling water temperature is low, the pre-permissible change amount is increased to prevent the generation of white smoke from increasing. Further, in another embodiment of the present invention, when the traveling speed of the vehicle is high, the permissible change amount is increased to prevent deterioration of vehicle driving performance during acceleration and to reduce white light during deceleration. This prevents the generation of smoke and improves the effectiveness of engine braking. Furthermore, in another embodiment of the present invention, during sudden acceleration when the amount of change in the accelerator opening is large in the positive direction, the allowable amount of change is made large; on the other hand, when the amount of change in the accelerator opening is negative When there is a sudden deceleration in the direction of the vehicle, the permissible change amount is made small to improve the acceleration performance and the effectiveness of the engine brake.

[Effect]

In the present invention, when performing smoothing processing on the fuel injection amount or accelerator opening, the allowable change amount is set to at least one of engine cooling water temperature, vehicle running speed, engine rotation speed, and accelerator opening amount. As a result, it is possible to perform highly accurate control that is well adapted to the vehicle condition, effectively preventing shocks during acceleration and deceleration over a wide driving range. It is possible to prevent the generation of white smoke.

【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, 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 (a feed pump 16) fixed to the drive shaft 14 for pumping fuel. Figure 2 is
The drive shaft 14 rotates by a predetermined crank angle due to the rotational displacement of the fuel pressure regulating valve 18 for adjusting the fuel supply pressure and the gear 20 fixed to the drive shaft 14 (showing a state rotated by 90 degrees). A rotational speed sensor 22 consisting of an electromagnetic pickup, for example, for measuring the time required for the rotational speed of the diesel engine 10, a roller ring 24 for controlling the fuel injection timing, and a roller ring 24 for driving the roller ring 24. A timer piston 26, a timing control valve 28 for controlling the position of the timer piston 26, a timer position sensor 30 comprising, 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 3
2, a plunger 34a, a compression spring 34b, a coil 34c, and a coil case 34d.
a spill actuator 34 consisting of a spill actuator 34, a spill position sensor 36 consisting of, for example, a variable inductance sensor for detecting the position of the spill ring 32 from the displacement of the plunger 34, and a fuel cut solenoid (for cutting off fuel when the engine is stopped). (hereinafter referred to as FCV) 38, a plunger 40, and a delivery valve 42. An exhaust 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 similarly detecting the temperature of the intake air, and the diesel engine 10.
a water temperature sensor 52 for detecting the engine cooling water temperature, which is disposed on the cylinder block 10a;
An accelerator sensor 54 for detecting the depression angle of an accelerator pedal 53 operated by the driver (hereinafter referred to as accelerator opening degree), and a manual transmission 5 for changing the gear ratio according to the driving condition of the automobile.
5, a vehicle speed sensor 56 for detecting the traveling speed of the automobile, that is, the vehicle speed, from the rotational speed of the output shaft of the manual transmission 55, and a shifter for detecting the shift position, that is, the shift position of the manual transmission 55. The target injection timing is determined based on the position switch 57, the accelerator opening degree detected from the output of the accelerator sensor 54, the engine rotation speed detected from the output of the rotation speed sensor 22, the engine coolant temperature detected from the output of the coolant temperature sensor 52, etc. and the calculated injection amount, and the timing control valve 28 and the spill actuator 3 are controlled so that the calculated injection amount of fuel is injected from the fuel injection pump 12 at the target injection timing.
Electronic control unit (hereinafter referred to as ECU) that controls
) 58. 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 which is input via the buffer 64, the output of the accelerator sensor 54 which is input via the buffer 66, and the buffer 67.
The spill position sensor 36 output is driven by the sensor drive frequency signal of the vehicle speed sensor 56 output and the sensor drive circuit 68 output, and is input via the sensor signal detection circuit 70;
The timer position sensor 3 is also driven by the sensor drive frequency signal output from the sensor drive circuit 72 and is input via the sensor signal detection circuit 74.
Multiplexer 76 for sequentially taking in 0 output etc.
and 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.
, an input/output port 80 for inputting the output of the A/D converter 78 into the CPU 59, an input/output port 84 for inputting the output of the shift position switch 57 inputted via a buffer 82, The speed sensor 22 output is waveform-shaped and sent to the CPU 59.
A waveform shaping circuit 94, a clock generation circuit 102, and a backup random access memory (hereinafter referred to as backup RAM) for temporarily storing data calculated by the CPU 59, which is backed up in the event of a power failure. Random access memory (hereinafter referred to as RAM) 104, and read-only memory (hereinafter referred to as RAM) for storing control programs, various data, etc.
a drive circuit 108 for driving the timing control valve 28 in accordance with the calculation result in the CPU 59;
The FCV3 according to the calculation result in the CPU59
8 and a digital-to-analog converter (hereinafter referred to as a D/A converter) 110 converts the signal into an analog signal.
According to the deviation between the CPU 59 output and the spill position sensor 36 output, the spill actuator 3
4 and a servo amplifier 112 and a drive circuit 114. The effects of the embodiment 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,
First, in step 110, the engine cooling water temperature determined from the output of the water temperature sensor 52 is set to a predetermined value, e.g.
Discover whether it is below 60℃. When the determination result is positive, that is, when it is determined that the engine coolant temperature is low, the process proceeds to step 112, and relatively large values are set as the allowable increase amount α ₁ and allowable decrease amount β ₁ according to the engine coolant temperature. , for example 0.5, 0.3
Put in. On the other hand, if the judgment result in step 110 is negative, the process proceeds to step 114, where the allowable increase amount α ₁ and allowable decrease amount β ₁ according to the engine cooling water temperature are set to relatively small values, for example, 0.20, respectively.
Enter 0.13. After completing step 112 or 114, step 116
Then, it is determined whether the vehicle speed determined from the output of the vehicle speed sensor 56 is less than a predetermined value, for example, 40 km/h. If the determination result is positive, the process proceeds to step 118, where the allowable increase amount α ₂ ,
The allowable reduction amount β ₂ is a relatively small value,
For example, enter 0.24 and 0.16. On the other hand, the previous step
If the determination result in step 116 is negative, that is, if it is determined that the vehicle speed is high, the process proceeds to step 120, where the allowable increase amount α ₂ and allowable decrease amount β ₂ are determined according to the vehicle speed.
Enter relatively large values, such as 0.30 and 0.25, respectively. After completing step 118 or 120 above, step 122
Then, it is determined whether the shift position of the manual transmission 55 is the first gear according to the output of the shift position switch 57. If the determination result is positive, that is, if it is determined that the shift position is the low-speed 1st speed, the process proceeds to step 124, where the allowable increase amount α ₃ and allowable decrease amount β ₃ are determined according to the shift position, respectively. , enter a relatively small value, e.g. 0.24, 0.16. On the other hand, if the judgment result in step 122 is negative, the process proceeds to step 126, where the permissible increase amount α ₃ and permissible decrease amount β ₃ according to the shift position are set to relatively large values, for example, 0.32 and 0.27, respectively. Put in. After completing step 124 or 126 above, step 128
The engine rotation speed NE is set to a predetermined value, for example, according to the output of the rotation speed sensor 22.
Determine whether the speed exceeds 2500 rpm. If the determination result is positive, that is, if it is determined that the engine speed is high, the process proceeds to step 130, and relatively large values are set as the allowable increase amount α ₄ and allowable decrease amount β ₄ according to the engine speed. value, e.g.
Enter 0.27 and 0.20. On the other hand, if the judgment result in step 128 is negative, proceed to step 132,
Relatively small values, for example 0.24 and 0.16, are entered as the allowable increase amount α ₄ and allowable decrease amount β ₄ depending on the engine rotation speed, respectively. After completing step 130 or 132, step
Proceeding to step 134, the maximum values of the allowable increases α ₁ , α ₂ , α ₃ , α ₄ and the allowable decreases β ₁ , β ₂ , β ₃ , β ₄ are determined as the final values as shown in the following equations. Let the allowable increase amount α and the allowable decrease amount β. α←MAX [α ₁ , α ₂ , α ₃ , α ₄ ] …(1) β←MAX [β ₁ , β ₂ , β ₃ , β ₄ ] …(2) After completing step 134, proceed to step 136. Go on,
A target value Qi of the fuel injection amount is calculated according to the engine rotational speed determined from the output of the rotational speed sensor 22, the accelerator opening degree determined from the output of the accelerator sensor 54, and the like. Next, the process proceeds to step 138, where it is determined whether or not the vehicle is accelerating, for example because the accelerator opening is increasing. If the determination result is positive, the process proceeds to step 140, where the fuel injection amount is gradually increased by the allowable increase amount α determined in step 134 from the fuel injection amount immediately before the acceleration determination to the target value Qi. By doing so, the fuel injection amount is smoothed. On the other hand, if the determination result in step 138 is negative, the process proceeds to step 142, where it is determined whether the vehicle is decelerating, for example, since the accelerator opening is decreasing. If the determination result is positive, the process proceeds to step 144, where the fuel injection amount is gradually increased from the fuel injection amount immediately before the deceleration determination to the target value Qi by the allowable decrease amount β determined in the aforementioned step 134. The fuel injection amount is smoothed by reducing it to . On the other hand, if the determination result in step 142 is negative, that is, if it is determined that there is no need to perform the smoothing process during acceleration and deceleration, the fuel injection amount is controlled to match the target value Qi. . In this way, the allowable changes in fuel injection amount α, β
By changing the speed according to the engine cooling water temperature, vehicle speed, gear shift position of the transmission, engine rotational speed, etc., acceleration/deceleration shock can be effectively reduced over a wide driving range. Further, even in a diesel engine equipped with an intake throttle device, no white smoke is generated. In this embodiment, each of the allowable increases α ₁ ,
As α ₂ , α ₃ , α ₄ and allowable reduction amount β ₁ , β ₂ , β ₃ , β ₄ ,
The control is simple because each of them takes two values, large and small. Note that it is also possible to obtain the allowable increase amount and allowable decrease amount using a calculation formula as a function of engine cooling water temperature, etc. In addition, in this embodiment, the allowable change amount is changed according to four parameters: water temperature, vehicle speed, gear shift position, and engine speed, and the final allowable change amount is the maximum value, so that fine-grained changes can be made. Control is performed, and the allowable amount of change is easily determined. Note that the number of parameters, the method of determining the final allowable change amount, etc. are not limited to these. In the above embodiment, during acceleration or deceleration, the allowable increase amount α and the allowable decrease amount β are uniform, respectively.
However, the values of the allowable increase amount α and allowable decrease amount β are changed depending on the amount of change in the accelerator opening. For example, if the amount of change in the accelerator opening is large in the positive direction, During a certain sudden acceleration, the permissible increase amount α is set to be large, while during a sudden deceleration when the amount of change in the accelerator opening is large in the negative direction, the permissible decrease amount β is set to be small, so as to be more appropriate for sudden acceleration/deceleration. It is also possible to perform a smoothing process. Further, in the above embodiment, the smoothing process during acceleration/deceleration was performed on the fuel injection amount, but the target to which the smoothing process is performed is not limited to this, and the smoothing process is performed on the accelerator opening degree. It is also possible to configure the system to perform the following. In the above embodiments, the present invention was applied to an electronically controlled diesel engine for an automobile equipped with a manual transmission, but the scope of application of the present invention is not limited thereto, and is applicable to an automobile equipped with an automatic transmission. It is clear that the present invention can be similarly applied to electronically controlled diesel engines and general diesel engines.

【Effect of the invention】

As described above, according to the present invention, shocks during acceleration and deceleration can be effectively reduced over a wide driving range by performing highly accurate control that is well adapted to the state of the vehicle. Further, even in a diesel engine equipped with an intake throttle device, the generation of white smoke can be reduced. Therefore, it has the excellent effect of improving vehicle driving performance and exhaust gas purification performance.

[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 automobile diesel engine equipped with a manual transmission to which the present invention is applied; FIG. 3 is a sectional view including a partial block diagram; FIG. 4, which is a block diagram showing the configuration of the electronic control unit used in the example, is also a flowchart showing the main part of the routine for calculating the fuel injection amount. 10... Diesel engine, 12... Fuel injection pump, 22... Rotational speed sensor, 52... Water temperature sensor, 54... Accelerator sensor, 55... Manual transmission,
56...Vehicle speed sensor, 57...Shift position 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 engine rotation speed and the accelerator opening, when accelerating or decelerating, the fuel injection amount or the accelerator opening is rounded to determine the acceleration/deceleration. In the fuel injection amount smoothing control method for a diesel engine that reduces the amount of fuel injection, the fuel injection amount is Or, a procedure for determining the allowable change amount of the accelerator opening, a procedure for determining the target value of the fuel injection amount or the accelerator opening from the engine speed, accelerator opening, etc., a procedure for determining that the engine is accelerating, and a procedure for determining that the engine is accelerating. When this is the case, a procedure for gradually increasing the fuel injection amount or accelerator opening by the above-mentioned permissible change amount so as to approach the target value, a procedure for determining that deceleration is in progress, and a procedure for determining that deceleration is in progress; , a step of decreasing the fuel injection amount or the accelerator opening degree by the permissible change amount so as to gradually approach the target value. 2. The permissible amount of change in the amount of fuel injection or accelerator opening is determined as the maximum value of the permissible change amount according to the engine cooling water temperature, the permissible change amount according to the vehicle running speed, and the permissible change amount according to the engine rotation speed. A fuel injection amount smoothing control method for a diesel engine according to claim 1. 3. The fuel injection amount smoothing control method for a diesel engine according to claim 1 or 2, wherein when the engine cooling water temperature is low, the allowable change amount is increased. 4. Claim 1, in which the permissible change amount is increased when the traveling speed of the vehicle is high.
The fuel injection amount smoothing control method for a diesel engine according to item 1 or 2. 5. During sudden acceleration when the amount of change in the accelerator opening is large in the positive direction, the allowable change is made large; on the other hand, during sudden deceleration when the amount of change in the accelerator opening is large in the negative direction, the allowable change is set to be large. A fuel injection amount smoothing control method for a diesel engine according to claim 1, wherein the fuel injection amount is reduced.