JPH0735746B2 - Fuel injection amount control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel injection amount control device for controlling the fuel injection amount of a diesel engine, and in particular, to a fuel that is stable against variations in performance of component parts and aging. The present invention relates to a device that realizes an injection amount.

[Conventional technology]

Conventionally, as a fuel injection device for a diesel engine, a predetermined fuel injection is performed based on a signal of each sensor such as a sensor that detects a depression amount of an accelerator pedal, a rotation speed sensor that detects an operating state or an environmental state, a water temperature sensor, and the like. The target fuel injection amount is calculated from the fuel amount map, and a signal corresponding to this target fuel injection amount is sent to an actuator such as a linear solenoid of the fuel injection pump to control the control rack for adjusting the injection amount, thereby controlling the injection amount. There is an apparatus for performing the above (for example, Japanese Patent Laid-Open No. 54-150519).

[Problems to be solved by the invention]

However, in the above conventional fuel injection control device, even if the target fuel injection amount is the same, the engine speed may fluctuate due to variations in engine characteristics, variations in injection characteristics of the fuel injection pump, or changes over time. There is a problem to do.

For example, in idle control, constant rotation control has been conventionally performed, but in this constant rotation control, the microcomputer controls the electric governor to perform fuel increase / decrease control regardless of the depression amount of the accelerator pedal. There is. But,
In the state where the no-load characteristic at the time of idling increases due to the change over time and the fuel injection amount is increased, the idle control is completed and the fuel injection amount is set by the predetermined injection amount fuel map by the depression amount of the accelerator pedal. However, there is a problem in that the engine speed is likely to drop sharply when the engine speed changes.

Therefore, the present invention has been made in view of the above problems,
It is an object of the present invention to provide a correction device for a fuel injection control device that enables stable rotation of the engine even if the engine has variations in characteristics and the like or changes over time.

[Means for solving problems]

In order to achieve the above object, the present invention, as shown in FIG. 1, in a fuel injection amount control device for controlling the fuel injection amount of diesel engine, detects an operation amount corresponding to the depression amount of an accelerator pedal. A manipulated variable detecting means, a rotational speed detecting means for detecting the rotational speed of the engine, and a target injection for computing a target injection amount based on previously calculated operational characteristics according to the operational amount and the rotational speed detected value. An amount calculation means, a fuel injection device for supplying fuel to the engine according to the target injection amount calculated by the target injection amount calculation means, and a constant rotation control for controlling the rotation speed of the engine to a predetermined rotation speed. Rotation speed feedback control means for increasing / decreasing the fuel injection amount from the fuel injection device so as to reduce the rotation speed deviation between the speed detection value and the predetermined rotation speed, and corresponding to the predetermined rotation speed. Correction means for correcting the calculation characteristic of the target injection amount calculation means in accordance with the deviation between the set injection amount set for this purpose and the actual injection amount given by the rotational speed feedback control means. The technical means called the fuel injection amount control device is adopted.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a system configuration diagram of a diesel engine and a fuel injection control device, I is a diesel engine, 2 is a fuel injection pump, and fuel injection is performed by controlling the energization time to the solenoid of the known electric governor 2a. The amount can be controlled. 3 is a transmission connected to the output shaft of the diesel engine 1.

The system is provided with various sensors, that is, an engine speed sensor 11 for detecting the engine speed of the diesel engine 1, an accelerator pedal amount sensor 13 for detecting the accelerator pedal depression amount, and an output shaft of the transmission 3. The vehicle speed sensor 15 and the water temperature sensor 17 for detecting the water temperature of the engine are provided respectively in the vehicle. The outputs of these sensors 11 to 17 are input to the electronic control unit 21.

The electronic control unit 21 is composed of a well-known microcomputer, that is, an input unit 23 that performs signal processing such as A / D conversion of signals from each sensor, a CPU 25, and a RAM 25 as a temporary storage unit, ROM 27 in which the programs shown in FIGS. 3 and 4 and the fuel injection amount map of FIG. 5 are stored in advance, a common bus 29, and control signals are D / A converted into signals for the electric governor 2a. The output unit 31 performs processing such as.

Next, the flowchart of FIG. 3 for obtaining the correction value of the fuel injection amount and performing the fuel injection control and the flowchart of FIG. 4 for performing the idle control (ISC control) as the constant rotation control will be described.

The flowchart of FIG.
It is activated twice. In FIG. 3, first, at step 100, it is judged from a signal from the accelerator depression amount sensor 13 or the like whether or not the vehicle is in an idle state. When it is determined in this step 100 that the engine is in the idle state, the routine proceeds to the next step 110, where constant rotation control is performed. This constant rotation control is performed by the flow chart as shown in FIG. That is, the engine speed Ne is read from the engine speed sensor 11 (step 200), and it is determined whether or not the speed Ne is controlled to a target predetermined speed Nf during idling (step 210), At the predetermined rotation speed Nf, the virtual operation amount αb of the accelerator pedal is not changed and maintained (step
220), maintaining the current fuel injection amount (step 230), while
When it is not the predetermined rotation speed Nf, the fuel injection amount is increased or decreased by increasing or decreasing the virtual operation amount of the accelerator pedal (step 240,
250). That is, feedback is performed based on the detection value of the engine rotation speed sensor 11 to obtain a virtual operation amount, and the fuel injection amount is obtained using this virtual operation amount as a parameter to control the engine rotation speed to a predetermined rotation speed. This virtual operation amount α
b is calculated so that this deviation becomes smaller in accordance with the proportional amount, integral amount, etc. of the deviation with respect to the predetermined rotation speed Nf, and the fuel injection quantity is calculated from the governor pattern as shown in FIG. The accelerator pedal depression amount Acc (in this case, the virtual operation amount αb) and the engine speed Ne are obtained as parameters. Here, the fuel injection amount at this time is Qi.

Next, at step 120, the relationship between the engine speed Ne and the target speed Nf in constant speed control is Nf≈Ne, that is, the fuel injection amount Qi when the speeds Ne and Nf are not so different from each other. average value of n Calculates the subsequently corrected fuel amount when the design value of the fuel injection amount when the Nf = Ne at no load was _{Q S Q D = Q G -Q} S
Is calculated (see FIG. 5). Here, the corrected fuel amount Q _D is a value corresponding to the variation amount of the injection amount of the diesel engine 1 and the fuel injection pump 2.

Then, in step 130, the corrected fuel amount Q _D is stored in the RAM 25 or the backup type memory. Then, in step 140, a control signal is sent to the solenoid of the electric governor 2a according to the above-mentioned fuel injection amount Qi, and fuel injection is performed.

If it is determined in step 100 that the vehicle is not in the idle state, the process proceeds to step 150, where the accelerator pedal depression amount Acc,
The target injection amount Qf is calculated from the engine speed Ne and the governor pattern in FIG.

Then, in step 160, it corrects the target injection amount Qf in the corrected fuel quantity Q _D which were stored at idle RAM 25. That newly calculates the Qf + Q _D, and the fuel injection amount Qil corrected. Explaining with reference to FIG. 5, if the governor pattern when the accelerator pedal depression amount Acc = αa is Gb, the corrected governor pattern Gbl is obtained. Next, at step 170, the fuel injection amount Qil is further corrected according to the detection values from other sensors. Then, similarly to the above, in step 140, fuel injection is performed according to the fuel injection amount Qil.

Therefore, according to the above process, during the constant speed control in the idle control, the fuel injection amount Qi for maintaining the constant speed is maintained.
Then, the corrected fuel amount Q _D is calculated from this fuel injection amount Q _i and the fuel injection amount Q _S when Nf = Ne at no load, and the target injection amount Q f during operation is corrected by this corrected fuel amount Q _D. is doing. Therefore, when the engine is controlled by the fuel and the injection amount corresponding to the accelerator pedal depression amount Acc by depressing the accelerator pedal from the constant rotation state by the idle control, due to the characteristics of the engine and the change with time, Even if the engine no-load characteristic and the fuel pump characteristic change, the engine speed does not change rapidly.

In the correction process according to the above-described embodiment, as shown in FIG. 6, the no-load characteristic of the virtual operation amount αb greatly changes depending on the engine water temperature.
The correction process of the present embodiment may be executed in the TA or higher area. In this case, it can be realized by adding a step of processing when the water temperature is equal to or higher than the predetermined temperature TA after step 110 in FIG. This processing is effective in reducing the software capacity, simplifying the configuration, and increasing the ROM flexibility.

Further, as another embodiment of the present invention, even in a system having no constant rotation control processing, it is possible to obtain the corrected fuel amount Q _D from the difference between the engine speed Ne in the idle state and the designed speed. is there. Further, not only the learning at one point of Ne = Nf, but the accuracy of the variation amount may be improved by learning the corrected fuel amount Q _D at a plurality of points.

〔The invention's effect〕

As described above, according to the present invention, the target injection amount is calculated from the preset calculation characteristic based on the operation amount of the accelerator pedal and the engine speed, and the fuel is supplied to the engine according to the target injection amount. It is supplied by injection. On the other hand, at the time of idling when the engine is controlled to a predetermined rotation speed, the fuel injection amount is increased or decreased so that the engine rotation speed becomes the predetermined rotation speed. Therefore, the actual injection amount given by the rotation speed feedback control means is compared with the preset injection amount for realizing the predetermined rotation speed,
The injection amount reflects the characteristic variation of each component and the change over time. Therefore, in the present invention, the calculation characteristic in the target injection amount calculation means is corrected according to the deviation between the preset injection amount corresponding to the predetermined rotation speed and the actual injection amount given by the rotation speed feedback control means. The fuel injection amount control other than the constant engine speed control reflects the injection amount that reflects the characteristic variation of each component part obtained during the constant engine speed control and the change over time. Therefore, even if there are variations in the characteristics of the diesel engine or fuel injection device or changes over time, the changes are reflected in the control of the fuel injection amount, so stable rotation of the engine can be obtained and the desired output can be reliably achieved. There is an effect that will be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of the configuration of the present invention, FIG. 2 is a system configuration diagram of a diesel engine according to an embodiment of the present invention, and FIG. 3 is a calculation process of a correction value and a fuel injection amount according to the same embodiment. FIG. 4 is a flowchart showing a constant rotation control process, FIG. 5 is a graph showing a governor pattern, and FIG. 6 is a graph showing a relationship between engine water temperature and accelerator depression amount. A: Diesel engine, B: Operation amount detection means, C:
Rotation speed detection means, D ... Target injection amount calculation means, E ... Fuel injection device, F ... Rotation speed feedback control device, G ...
... correction means.

Claims (3)

[Claims] 1. A fuel injection amount control device for controlling a fuel injection amount of a diesel engine, and an operation amount detecting means for detecting an operation amount corresponding to a depression amount of an accelerator pedal, and a rotation speed for detecting the rotation speed of the engine. A detection means, a target injection amount calculation means for calculating a target injection amount on the basis of a calculation characteristic preset according to the operation amount and the rotation speed detection value, and a target calculated by the target injection amount calculation means. A fuel injection device that supplies fuel to the engine in accordance with the injection amount, and during constant rotation control that controls the engine revolution speed to a predetermined revolution speed, reduces the revolution speed deviation between the revolution speed detection value and the predetermined revolution speed. As described above, the rotation speed feedback control means for increasing / decreasing the fuel injection amount from the fuel injection device, the preset injection amount corresponding to the predetermined rotation speed, and the rotation speed filter. Fuel injection amount control apparatus, characterized in that it comprises a correcting means for correcting the operation characteristics of the target injection quantity calculating means in accordance with the deviation of the actual injection quantity provided by Dobakku control means. 2. The fuel injection amount control device according to claim 1, wherein the rotation speed feedback control means is configured to function during idling. 3. The rotation speed feedback control means, a virtual operation amount calculation means for calculating a virtual value of the operation amount so as to reduce a rotation speed deviation between the rotation speed detection value and the predetermined rotation speed, The fuel injection according to claim 2, further comprising: idle-time injection amount calculation means for calculating an idle-time target injection amount according to the idle-time calculation characteristic set according to the virtual operation amount. Quantity control device.