JPH051382B2 - - Google Patents

Description

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

The present invention relates to a fuel injection amount acceleration 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 includes engine speed and accelerator opening. A fuel injection amount acceleration smoothing control method for a diesel engine in which acceleration shock is alleviated by performing acceleration smoothing processing on the fuel injection amount or accelerator opening during acceleration when determining the fuel injection amount according to the driving state. Regarding improvements.

[Prior art]

In diesel engines, especially electronically controlled diesel engines for automobiles, acceleration smoothing is performed by limiting the amount of change in fuel injection amount and accelerator opening during acceleration in order to alleviate acceleration shock. So-called fuel injection amount acceleration smoothing control has been proposed to alleviate the acceleration shock. For example, as shown by the dashed line A in Fig. 1, if the required injection amount changes all at once to Qa at time _t1 when the accelerator pedal is depressed and acceleration starts, if the fuel injection amount Q is increased as is. , since an acceleration shock occurs, the acceleration shock can be reduced by gradually increasing the fuel injection amount Q from the previous fuel injection amount Q _i-1 to the required injection amount Qa, as shown by the broken line B. be. However, driving force does not actually begin to be applied to a car equipped with a diesel engine until the fuel injection amount Q has increased to a certain extent, resulting in decreased responsiveness.
There were cases where a momentary time lag occurred the moment the accelerator was pressed, causing discomfort to the driver. In order to alleviate such problems, it is possible to uniformly weaken the degree of acceleration smoothing processing and increase the rising slope of the fuel injection amount, but in this case, it is possible to reliably prevent the occurrence of acceleration shock. Not only was it impossible to do so, but it was also impossible to completely eliminate the time lag before driving force was applied to the car.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned conventional problems, and is capable of eliminating the time lag at the start of acceleration without impairing the effect of reducing acceleration shock, thereby providing a diesel engine with a quick accelerator response. The present invention aims to provide a fuel injection amount acceleration smoothing control method.

[Structure of the invention]

When determining the fuel injection amount according to engine operating conditions including engine speed and accelerator opening, the present invention performs acceleration smoothing processing on the fuel injection amount or accelerator opening during acceleration to alleviate acceleration shock. In the fuel injection amount acceleration smoothing control method for a diesel engine, as summarized in FIG. During acceleration, a procedure for determining whether the required injection amount or required accelerator opening exceeds a set value, and the required injection amount or required accelerator opening exceeds the set value, and , when the previous fuel injection amount or accelerator opening is less than the set value, the set value is used as an initial value and the fuel injection amount or accelerator opening is gradually increased to the required injection amount or required accelerator opening. The procedure for starting acceleration smoothing processing, and when the required injection amount or required accelerator opening exceeds the set value, and the previous fuel injection amount or accelerator opening is greater than or equal to the set value, the fuel and a step of executing a normal acceleration smoothing process in which the injection amount or accelerator opening is gradually increased from the previous fuel injection amount or accelerator opening to the required injection amount or required accelerator opening. The purpose has been achieved. Further, in an embodiment of the present invention, the set value is set as a fuel injection amount or an accelerator opening degree at which driving force starts to be applied to a vehicle etc. equipped with a diesel engine,
In addition to minimizing the time lag at the start of acceleration,
This makes it possible to reliably reduce acceleration shock.

[Structure of the invention]

In the present invention, when the required injection amount or required accelerator opening exceeds the set value, and the previous fuel injection amount or accelerator opening is less than the set value, acceleration is not performed using the set value as the initial value. Since it has been decided to start the reduction process, the fuel injection amount Q is immediately increased to the set value Qs at the start of acceleration, as shown by the solid line C in FIG. 1 mentioned above. Therefore,
The response delay that conventionally occurred in response to the time Δt required for the fuel injection amount to increase from Q _i-1 to Qs is eliminated, and a good accelerator response can be obtained. Furthermore, when the fuel injection amount or the accelerator opening reaches the set value Qs or more, normal acceleration smoothing processing is performed, so that no acceleration shock occurs.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electronically controlled diesel engine for automobiles equipped with a manual transmission will be described in detail with reference to the drawings, in which the fuel injection amount acceleration smoothing control method for a diesel engine according to the present invention is adopted. As shown in FIG. 3, this embodiment includes an air cleaner 12 for introducing purified air from the outside into the diesel engine 10, and a device disposed in the air cleaner 12 for detecting the temperature of the intake air. A turbocharger 18 having an intake air temperature sensor 14 and a compressor 18A disposed in the middle of the intake pipe 16 for compressing intake air using exhaust gas energy.
and compressor 18A of said turbocharger 18
an intake throttle valve 22 that rotates in conjunction with an accelerator pedal 20 disposed on the driver's seat to limit the flow rate of intake air compressed by the intake air; and detecting the opening degree of the accelerator pedal 20. an accelerator sensor 24 for detecting the pressure of the intake air in the intake pipe 16 on the downstream side of the intake throttle valve 22;
, a drive shaft 34 that rotates in conjunction with the rotation of the crankshaft of the diesel engine 10, and a feed pump 36 for pumping fuel that is fixed to the drive shaft 34 (FIG. 2 shows a state in which it is unfolded at 90 degrees). ), a fuel pressure adjustment valve 38 for adjusting the fuel supply pressure, and an engine rotation sensor 42 consisting of, for example, an electromagnetic pickup, for detecting the rotational state of the diesel engine 10 from the rotational displacement of the gear 40 fixed to the drive shaft 34. , a roller ring 44 for controlling fuel injection timing, a timer piston 46 for driving the roller ring 44 (FIG. 2 shows a state in which it is unfolded at 90 degrees), and a timer piston 46 for controlling the position of the timer piston 46. A timing control valve 48, a timer position sensor 50 made of, for example, a variable inductance sensor for detecting the position of the timer piston 46, a spill ring 52 for controlling the fuel injection amount, and a spill ring 52 for driving the spill ring 52. a spill actuator 54 consisting of a plunger 54A, a compression spring 54B, a coil 54C and a coil case 54D; a spill position sensor 56 consisting of, for example, a variable inductance sensor, for detecting the position of the spill ring 52 from the displacement of the plunger 54A; Fuel cut solenoid (hereinafter referred to as
(referred to as FCV) 58, a fuel injection pump 3 having a pump plunger 60 and a delivery valve 62
2, an injection nozzle 70 for injecting fuel discharged from the delivery valve 62 of the fuel injection pump 32 into the combustion chamber 10A of the diesel engine 10, and a cylinder block 1 of the diesel engine 10.
A water temperature sensor 72 disposed at 0B for detecting the engine cooling water temperature; and a turbine of the turbocharger 18 disposed in the middle of the exhaust pipe 74 for rotating the compressor 18A using the thermal energy of exhaust gas. 18
B; an exhaust bypass passage 76 that bypasses the turbine 18B; and a compressor 18 of the turbocharger 18.
An exhaust bypass valve 78 opens the exhaust bypass passage 76 when the intake air pressure on the A outlet side exceeds a predetermined value to prevent excessive supercharging, and detects from the output of the accelerator sensor 24. The target injection timing and target injection amount are determined based on the accelerator opening degree detected from the engine rotation sensor 42, the engine rotation speed detected from the output of the engine rotation sensor 42, the engine cooling water temperature detected from the output of the water temperature sensor 72, etc., and the target injection amount is determined from the fuel injection pump 32. an electronic control unit (hereinafter referred to as ECU) 80 that controls the timing control valve 48, spill actuator 54, etc. so that a target injection amount of fuel is injected at the injection timing;
It consists of In the figure, 82 is a glow plug. The ECU 80, as shown in detail in FIG.
A central processing unit (hereinafter referred to as CPU) consisting of, for example, a microprocessor, performs various arithmetic processing.
A clock circuit 80B that generates various clock signals, and a random access memory (hereinafter referred to as RAM) that includes a backup random access memory that is backed up in the event of a power failure and is used to temporarily store calculation data etc. in the CPU 80A. ) 80C, a read-only memory (hereinafter referred to as ROM) 80D for storing control programs, various data, etc., and the water temperature sensor 7 inputted via the buffer 80E.
2 outputs, the output of the intake air temperature sensor 14 which is input via a buffer 80F, the output of the intake pressure sensor 28 which is input via a buffer 80G, and the accelerator sensor 2 which is input via a buffer 80H.
4 outputs, the spill position sensor 56 output is driven by the sensor drive frequency signal output from the sensor drive circuit 80I and is input via the sensor signal detection circuit 80J, and the sensor drive frequency signal is also output from the sensor drive circuit 80K. a multiplexer 80M for sequentially taking in the output of the timer position sensor 50, etc. driven by the timer position sensor 50 and input via the sensor signal detection circuit 80L, and the multiplexer 80
An analog-to-digital converter (hereinafter referred to as an A/D converter) 80N for converting an analog signal of M output into a digital signal, and the A/D converter 80N.
an input/output port 80O for inputting the output of the engine rotation sensor 42 into the CPU 80A; a waveform shaping circuit 80P for waveform shaping the output of the engine rotation sensor 42 and inputting it directly to the CPU 80A; Timing control valve 4
8 and a drive circuit 80Q for driving the CPU 80A.
A drive circuit 80R for driving the FCV58,
The CPU 80A output converted into an analog signal by a digital-to-analog converter (hereinafter referred to as a D/A converter) 80S and the spill position sensor 5
It is comprised of a servo amplifier 80T and a drive circuit 80U for driving the spill actuator 54 according to the deviation from the six outputs, and a common bus 80V that connects each of the component devices. The effects of the embodiment will be explained below. Calculation of the fuel injection amount in this embodiment is executed according to a routine as shown in FIG. That is, first, in step 110, the engine rotation speed determined from the output of the engine rotation sensor 42,
The accelerator opening degree determined from the output of the accelerator sensor 24, the engine cooling water temperature determined from the output of the water temperature sensor 72, and the intake pressure sensor 28.
The required injection amount Qa is calculated according to the intake pressure etc. determined from the output of. Next, the process proceeds to step 112, where it is determined whether the required injection amount Qa is greater than or equal to the fuel injection amount Q _i-1 used for the previous control. If the result of the determination is negative, the required injection amount Qa is output as is as the current target injection amount Qi in step 126, and this routine is ended. On the other hand, if the determination result in step 112 is positive, that is, if it is determined that the vehicle is in an acceleration state, the process proceeds to step 114, where it is determined whether or not acceleration smoothing processing is already in progress. If the determination result is positive, the process proceeds to step 116 to continue the acceleration smoothing process that has already been started, and in step 126 the fuel injection amount after the acceleration smoothing process is output as the current target injection amount Qi. and exit this routine. On the other hand, if the determination result in step 114 is negative, that is, if it is determined that the acceleration smoothing process has not yet been executed although the engine is accelerating, the process proceeds to step 118, and the required injection amount Qa is , a set value corresponding to the fuel injection amount at which driving force begins to be applied to a vehicle equipped with the diesel engine 10.
Determine whether it is greater than Qs. If the determination result is negative, the required injection amount is determined in step 126.
Qa is output as is as the current target injection amount Qi, and this routine ends. On the other hand, if the determination result in step 118 is positive, the process proceeds to step 120, where it is determined whether the previous fuel injection amount Q _i-1 is less than the set value Qs. If the judgment result is positive, step 1
Proceed to step 22 and set the above set value Qs to the current fuel injection amount.
Qi, and in step 126 the current target injection amount Qi
Outputs the set value Qs as , and ends this routine. As a result, accelerated smoothing processing is started with the set value Qs as the initial value. On the other hand, if the determination result in step 120 is negative, the routine proceeds to step 124, where normal acceleration smoothing processing is started using the previous fuel injection amount Q _i-1 as the initial value. As a specific method for the acceleration smoothing process in step 124, for example, the amount of fuel injection is adjusted according to the elapsed time after the start of acceleration, as already proposed by the applicant in Japanese Patent Application No. 142,173/1982. A method can be adopted in which an allowable change amount is determined and the fuel injection amount is gradually brought closer to the required injection amount Qa by the allowable change amount. The fuel injection amount determined in step 124 is output as the current target injection amount Qi in step 126, and this routine ends. In this way, when an increase in the required injection amount Qa is detected, the previous fuel injection amount Q _i-1 is brought to the set value Qs that provides driving force to the car, and the acceleration is stopped from that set value Qs. By performing the improvement processing, the response delay of the time Δt until the car starts moving is eliminated, and the accelerator response is improved. In this example, the set value Qs is set to the fuel injection amount at which driving force begins to be applied to a vehicle equipped with a diesel engine, thereby minimizing the time lag at the start of acceleration and reliably reducing acceleration shock. be able to. In addition, the setting value
The size of Qs is not limited to this, but it can be set to a value slightly larger than the fuel injection amount at which driving force begins to be applied to the car, to further enhance the effect of preventing time lag,
Alternatively, it is possible to ensure the effect of reducing acceleration shock by setting the value to be slightly smaller than the fuel injection amount at which driving force begins to be applied. In addition, in the above embodiment, the smoothing process was performed on the fuel injection amount during acceleration, but the target for the smoothing process is not limited to this, and the smoothing process is performed on the accelerator opening. It is also possible to do so. In the above embodiments, the present invention was applied to an electronically controlled diesel engine for automobiles equipped with a manual transmission, but the scope of application of the present invention is not limited thereto, and is applicable to an automatic transmission equipped with a lock-up mechanism. It is obvious that the present invention can be similarly applied to an electronically controlled automobile diesel engine equipped with the present invention and a general diesel engine.

【Effect of the invention】

As described above, according to the present invention, it is possible to eliminate the time lag at the start of acceleration without impairing the effect of reducing acceleration shock, and to obtain a rapid acceleration response. Therefore, it has the excellent effect of improving drive feeling.

[Brief explanation of the drawing]

FIG. 1 is a diagram comparing and showing changes in the fuel injection amount during acceleration in the conventional example and the embodiment of the present invention, and FIG. 2 is a diagram showing the fuel injection amount acceleration smoothing of the diesel engine according to the present invention. FIG. 3 is a flowchart showing the gist of the control method; FIG. 3 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 adopted; FIG. 4 is a block diagram showing the configuration of the electronic control unit used in the embodiment, and FIG. 5 is a flow chart showing the main part of the routine for calculating the fuel injection amount. DESCRIPTION OF SYMBOLS 10... Diesel engine, 20... Accelerator pedal, 24... Accelerator sensor, 32... Fuel injection pump, 42... Engine rotation sensor, 54... Spill actuator, 70... Injection nozzle, 80... Electronic control unit (ECU), Qa...Required injection amount, Q _i-1 ...Previous fuel injection amount, Qs...Set value.

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, the fuel injection amount or the accelerator opening is subjected to acceleration smoothing processing. In the fuel injection amount acceleration smoothing control method for a diesel engine that is designed to alleviate the A procedure for determining whether the required injection amount or required accelerator opening exceeds a set value, and the required injection amount or required accelerator opening exceeds the set value, and
When the previous fuel injection amount or accelerator opening is less than the set value, the set value is used as an initial value and the fuel injection amount or accelerator opening is gradually increased to the required injection amount or accelerator opening. The procedure for starting the smoothing process, and when the required injection amount or required accelerator opening exceeds the set value, and the previous fuel injection amount or accelerator opening is greater than or equal to the set value, fuel injection is performed. amount or accelerator opening,
Accelerating the amount of fuel injection in a diesel engine, comprising the steps of: executing normal acceleration smoothing processing that gradually increases from the previous amount of fuel injection or accelerator opening to the required injection amount or required accelerator opening. Annealing control method. 2. Claim 1, wherein the set value is a fuel injection amount or an accelerator opening degree at which driving force starts to be applied to a vehicle equipped with a diesel engine, etc.
A fuel injection amount acceleration smoothing control method for a diesel engine as described in .