JPS61182441A - Control method of fuel injector - Google Patents

Abstract

PURPOSE:To correct the amount increase of acceleration fuel by carrying-out fuel injection into a cylinder in the preceding time in which the driving time for an injector is determined, besides the fuel injection for the cylinder in this time in sharp acceleration. CONSTITUTION:A Carman vortex air flow sensor 5 is installed onto the upstream side of a throttle valve 6 in the intake passage of an engine 2, and a crank position sensor 9 for generating a standard signal is installed. The fuel injection starting timing of an injector 4 is synchronized with each standard signal through a control unit 7, and the fuel injection timing is corresponded with the number of Carman vortex signals generated in the former and the latter standard signals. When the fuel injection timing exceeds the fuel injection timing in the preceding time by a set time or more in the above-described injection control, the injector 4 driven in the preceding time is synchronized with the standard signal for the differential time and driven again.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of controlling a fuel injection device, and particularly to a method of controlling a fuel injection device that can change the fuel injection time with good response during sudden acceleration.

Conventional technology Conventionally, fuel injection systems determine the basic injection amount per stroke based on engine speed and intake air amount, and increase the amount according to engine information such as starting, acceleration, water volume, intake air temperature, etc. Add corrections.

Of this increase correction, in order to perform acceleration correction, throttle information for acceleration detection is required in addition to normal throttle opening information.

By the way, a fuel injection device is known in which the amount of intake air is determined based on the Karman vortex signal of the Karman vortex air flow sensor and the fuel supply amount is determined based on this and the engine rotation speed. In such a fuel injection system, the Karman vortex number is counted between each reference signal synchronized with engine rotation, and an injector synchronized with each reference signal is operated to supply proportional fuel to each cylinder.

Problems to be Solved by the Invention Incidentally, the amount of fuel supplied to each cylinder is based on the seven Karman vortex numbers between the reference signal preceding the determination of the fuel amount and the previous reference signal. However, if a sudden acceleration occurs between the injection of the determined amount of fuel and the end of the intake stroke of the cylinder that is synchronized with this reference signal, and a large change in the intake air amount occurs, the cylinder The engine will inevitably become lean, which can lead to the worst case scenario, 2+, z-coupling, misfire, and engine stall. The purpose of the present invention is to
It is an object of the present invention to provide a control method for a fuel injection device that can be performed using only an acceleration-corrected Karman vortex signal.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a reference signal which is a pulse signal generated from a crank position sensor in synchronization with the rotation of the crank 7 shaft, and a pulse signal which is proportional to the amount of intake air to the engine. The timing of fuel injection by the injector is synchronized with each reference signal using the Karman vortex signal, which is a pulse signal generated from the Karman vortex air flow sensor. The fuel injection time is made to correspond to the number of Karman vortex signals generated between the first reference signal and the previous reference signal preceding the first reference signal, and is synchronized with this after the first reference signal is generated. When the fuel injection time by the injector that is driven by the previously driven injector exceeds the fuel injection time by the previously driven injector by the set time or more,
The feature is that the previously driven injector is driven again in synchronization with the first reference signal for the difference time.

Actual Example Figure 1 shows a fuel injection device 1 to which the fuel injection device control method of the present invention can be applied.

This fuel injection device 1 is attached to a four-cylinder Ganlin engine (hereinafter simply referred to as engine) 2T/c, and uses an injector 4 in its intake manifold 6 to inject fuel at a timely manner. A throttle valve 6 is installed on the intake path of the engine 2, and a well-known θ Kukarman vortex air flow controller 5 is installed on the upstream side of the valve 6, which generates a pulse signal in proportion to the intake air amount of the engine. A certain Karman vortex signal K is sent to the control unit 7. A crank position sensor 9 is provided opposite to the engine crank 7 shaft 8Vc.

The sensor 9 sends out a reference signal, which is a pulse signal, in synchronization with the rotation of the crank 7 and shaft 8, that is, the engine rotation, and in synchronization with a predetermined stroke of each cylinder. In addition, here, the intake stroke (INT) of each cylinder is shown in Figure 6 ((shown) @9).
The reference signal C is set to be emitted at 0°, and after the stiffness reference signal is generated, each injector 4 injects fuel into the cylinder synchronized with this signal (see Figure 6 and Figures 1 and 4). The operating order of each cylinder of engine 1 is $1. $3.
It is 4° and 1. control unit 7
are the Karman vortex signal K and the reference signal C? In addition, the injector drive signal is sent out based on the fuel injection start timing and fuel injection time Tci by the injector 4.
control.

The CPU 7a of this control unit 7 has 6
There are two external interrupt terminals, one of which is terminal I.
The Karman vortex signal K is input to NT1, and the reference signal C is input to the other terminal INT2 (see Figure 2). The CPU 7a is connected to a free running counter 7C via a bus 70, and the counter 7a
The overflow signal of c is sent to terminal I of CPU 7a.
NT3K is input. This (CPU 7a
reads the value of counter 7C at any timing,
You can measure any time.

The CPU 7a performs operations as shown in the flowchart of FIG. First, we will explain how to calculate the injector driving time Td corresponding to the fuel injection time (this driving time includes the total operating time which is the injector's operation delay) using the Karman vortex signal and the reference signal C. I'll keep it.

The injector driving time Td, that is, the basic fuel injection time is calculated by adjusting the intake air amount Qa/engine rotation speed NB
The intake air ratio Qa is proportional to the frequency Fx of the Karman vortex signal, and the engine rotation aN2 is inversely proportional to the period Tc of the reference signal C, so that 'ra QCFx X Tc is obtained. Therefore, the actual injector driving time Td
For calculation, for example, based on the waveform diagram π shown in FIG. 5, six Karman vortex signals 1. K2. Since there is K3, the frequency FK, that is, the Karman vortex number Np is Td ==
K-Np becomes 10. Note that the constant viC and coefficients are determined in advance.

By the way, according to such a counting method of the Karman vortex number Np, even if similar Karman vortex numbers occur, there are variations based on the difference in the relative positions of the - set of reference signals and Karman vortex signals. (In the example shown by the VC double-dashed line in Figure 5, the Karman vortex number is one less than the solid line, and is two.) The following method may be used to prevent this. This method was previously proposed by the present applicant (Electronic Control 1 Control Method for Fuel Injection Device, Patent filed on April 13, 1980) and has a detailed description.

That is, as shown in Figures 5 and 6, the time width (TI
, T3) is calculated for a set of Karman vortex signals preceding these time widths using the intervening time width (shown as T2.TA), obtained as a value below the decimal point, and then added to the integer domain. The Karman vortex number of is added. In other words, as shown in Fig. 5, when π is larger than π, these values are regarded as 1, and the reference signal C
2.

=2+1-1).

Here, the method of the present invention will be explained with reference to the flowchart shown in FIG.

CPU 7a of the control unit c) (During the routine, engine information is sequentially imported, and the coefficient Ka necessary to obtain a predetermined air-fuel ratio A/F based on acceleration, deceleration, starting status, water wetness, and intake temperature and a constant Ca.Then, each time the Karman vortex signal K interrupts, the Karman vortex interrupt routine is executed.

Here, each time a Karman vortex signal enters, the Karman vortex number Np
is reset by +1 and returns to the main routine. Note that only when counting down to the decimal point, such as the Karman vorticity number described later, the operations within the two-dot chain line are executed continuously. That is, the period TKk of the Karman vortex is calculated from the time difference between this time and the previous time, and is stored and processed. Furthermore, the current time is stored and the process returns to the main routine.

On the other hand, in the main routine, when the reference signal C interrupts, the reference signal interrupt routine is executed. Here, cylinder discrimination is performed based on the reference signal, and then the Karman vortex number NF is calculated. In this case, the above-mentioned Karman vortex number Np can be called directly and used, or alternatively, as shown in Figure 8, the Karman vortex number C between one reference signal C and its previous reference signal can be The number of vortices may be calculated down to a decimal number. That is, first, the generation time T of the reference signal
Read C. And the latest data on Karman vortex period TK
(T2 in Figure 5) is the current reference signal C
The time width TC-T between and the Karman vortex signal just before that
A (']'1 in Figure 5) is removed, and if this is greater than 1, then YES side (corresponds to the case in Figure 16)
If no, proceed to the NO side (corresponding to the case of Figure 5).Y
On the ES side, the Karman vortex number Np is obtained by subtracting the previous preemption fraction - 1, which is considered to be 1, from the integer fraction. Furthermore, 1, which is the pre-emption amount this time, is set as FRAC=1. On the other hand, on the NO side, the Karman vorticity number Np is an integral number,
Add the current light acquisition T1 minute - which is below the decimal point, and add the previous light acquisition minute - which is below the decimal point.
Subtract and find again. Furthermore, this time, the preemption numerator 4 is set as - ).

According to the method shown in Figure 8, it is possible to obtain a Karman vorticity number Np with a higher index.

Following such calculation of the Karman vortex number, constant @Ca and coefficient Ka obtained in the main routine were used.

Driving time Td (=Ka-Np+Ca)
Calculate. After this, the previous drive time TO is sufficient (
The set time τ is a value that is sufficient to obtain a nitrous fuel ratio that is suitable for starting fuel increase, etc. If above, YES but II, otherwise N.
o Go to old +1. In No lJj+, it is further determined whether the current drive time Td exceeds the previous drive time To by a set time τd or more, and the process goes to YES or NO. That is, to explain in Figures 6 and 4, fuel injection by the 3rd injector to the 3rd cylinder is performed by the 4th injector after tl time. When sudden acceleration is performed before injection into the 4 cylinders, the engine is on the YES side, and at other times, for example! The injection point in the J66 cylinder is higher than the F1 cylinder.
Become a side. YES (In ij+, the previously driven injectors (6 injectors in Fig. 4) are immediately re-driven for the difference time (Td - To). This time is immediately after the reference signal C3, and the previous cylinder is ( Figure 6: Since the I6 cylinder is in the suction stroke, the fuel injected by the re-driving will be in time for the suction stroke.For this reason, the previous cylinder will be effectively injected (the two points in the C16 diagram). The increase in quantity as shown by the chain line is achieved with good transient response.Furthermore, the injector to be driven this time (injector 4/injector in Fig. 4) is driven for a driving time Td.
drive only. Thereafter, the drive time Td is stored and updated as the previous drive time TO in preparation for the next injection. Furthermore, the stored value of the Karman vortex number Np is also cleared and the process returns to the main routine.

Effects of the Invention According to the &l control method of the fuel injection device according to the present invention,
During sudden acceleration, fuel is injected into the cylinder receiving the current fuel injection for the previous cylinder whose injector drive time was determined prior to this sudden acceleration, and the IIF cylinder/previously driven injector injects again. , Pivotal? and perform acceleration increase correction. Therefore, without receiving a 5 throttle signal due to special sudden acceleration, acceleration and fuel increase corrections can be made in a responsive manner to the cylinders that were originally lean during the transition period, and cylinder misfires and engine stalls can be prevented. . Furthermore, by using this method, acceleration correction can be performed without the need for rematching due to changes in engine/engine type displacement, throttle type, surge tank, etc.

[Brief explanation of the drawing]

Figure 11 is a schematic diagram of a fuel injection system to which the method of the present invention can be applied, Figure 2 is a schematic diagram of the control unit in Figure 1, and Figure 6 is a stroke diagram of the engine to which the fuel injection system is installed. The waveform diagram of each synchronized element, Figure 4 is a waveform diagram of the injector synchronized with Figure 6, Figure 5 and Figure 6 are waveform diagrams explaining the relative relationship between the reference signal and the Karman vortex signal, respectively. Figures 1 and 7 and Figure 8 are C of Figure 2.
7 shows flowcharts of operating programs that can be built into each PU. 4... Injector, 5... Air flow sensor, 8... Crankshaft, 9... Crank position sensor, C... Reference signal, K... Karman vortex signal) δ (rotation) prediction 4 shaku reed ω mouth most l

Claims (1)

[Claims] Using a reference signal, which is a pulse signal generated from a crank position sensor in synchronization with the rotation of the crankshaft, and a Karman vortex signal, which is a pulse signal generated from a Karman vortex air flow sensor in proportion to the amount of intake air into the engine. , the start timing of fuel injection by the injector is synchronized with each reference signal, and the time of fuel injection by the injector that starts after generation of any one reference signal is synchronized with one reference signal and the previous time preceding the one reference signal. In a control method for a fuel injection device that corresponds to the number of Karman vortex signals generated between a reference signal and a reference signal, the fuel injection time of an injector that is driven in synchronization with the first reference signal is determined by the fuel injection time of the previously driven injector. A control method for a fuel injection device, characterized in that when the injection time exceeds a set time, a previously driven injector is driven again in synchronization with a reference signal by the difference time.