JPH0229853B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel injection control method in an electronic control device for an automobile engine.

BACKGROUND ART FIG. 2 schematically shows a conventional fuel injection control device using a microcomputer. In Fig. 2, 1 is a four-cylinder engine, 2 is an intake pipe that communicates with each combustion chamber of engine 1, and 3 is a throttle body provided in the middle of intake pipe 2. A valve opening sensor 4 is connected. 5 is a fuel injection device, and this fuel injection device 5 is provided for each cylinder. 6 is an intake air temperature sensor, and 7 is an intake pipe pressure sensor. 8 is a rotational speed sensor, and 9 is a cylinder discrimination sensor.The rotational speed sensor 8 outputs a TDC signal (Fig. 3B) every 180° rotation of the crankshaft, and the cylinder discrimination sensor 9 outputs a TDC signal (Fig. 3B) for each 180° rotation of the crankshaft. A cylinder discrimination signal (FIG. 3A) is output at a predetermined crank angle position. 10 is an engine water temperature sensor,
11 is a battery voltage detection circuit, and 12 is a starter switch that controls current supply to the starter motor. Throttle valve opening information from the throttle valve opening sensor 4, intake temperature information from the intake temperature sensor 6, intake pipe pressure information from the intake pipe pressure sensor 7, engine speed information from the rotation speed sensor 8,
Water temperature information from the water temperature sensor 10, battery voltage information from the battery voltage detection circuit 11, and on/off information from the starter switch 12 are input to the engine control unit 13. The engine control unit 13 is composed of a microcomputer, etc., and calculates the pulse width of the fuel injection control pulse based on the engine parameter information from each of the sensors, and outputs the fuel injection control pulse with the pulse width determined by this calculation. , is output to the fuel injection device 5 in synchronization with the TDC signal.

The pulse width τ of the fuel injection control pulse in the engine control unit 13 is, for example, lower than the basic injection amount τ ₀ , the water temperature correction coefficient K ₁ , the intake temperature correction coefficient K ₂ , and the pulse width correction value τ ₁ based on the battery voltage fluctuation. Calculated based on the formula.

τ=τ ₀ ×K ₁ ×K ₂ +τ ₁ The above basic injection amount τ ₀ is based on the intake pipe pressure information I ₁ from the intake pipe pressure sensor 7 and the engine rotation speed information I ₂ from the rotation speed sensor 8. Desired. These intake pipe pressure information I ₁ and engine speed information I ₂
is input to the engine control unit 13 and calculated in synchronization with the fuel injection timing. In addition, engine parameters necessary for calculating the water temperature correction coefficient K ₁ , intake temperature correction coefficient K ₂ and pulse width correction value τ ₁ , that is, water temperature information I ₃ from the engine water temperature sensor 10,
Intake temperature information I ₄ from intake temperature sensor 6, throttle valve opening information I ₅ from throttle valve opening sensor 4
is input and calculated in idle time asynchronously with the fuel injection timing (TDC signal). The calculation of the pulse width τ of the fuel injection control pulse described above is performed subsequent to the calculation of the basic injection amount τ ₀ which is performed in synchronization with the fuel injection timing, and as soon as the calculation of the pulse width τ is completed, the fuel injection control pulse is Injection device 5
is output to.

Note that the engine speed is determined by the engine speed sensor 8.
The starter switch 12 is determined by measuring the time between the TDC signals output from the
After turning on, engine speed cannot be measured unless two TDC signals are input. Therefore, the pulse width τ of the fuel injection control pulse cannot be calculated until the two TDC signals are input after the starter switch 12 is turned on.

Therefore, in the above conventional example, the starter switch 1
2, first initialize the pulse width of the fuel injection control pulse and the information corresponding to the above various input information I ₁ , I ₂ , I ₃ , I ₄ , I ₅ , and use these initial settings. Based on this, the basic injection amount τ ₀ is calculated, and the water temperature correction coefficient K ₁ , intake temperature correction coefficient K ₂ , and pulse width correction value τ ₁ are calculated. If the fuel injection start timing comes before the calculation of the above-mentioned water temperature correction coefficient K ₁ , intake temperature correction coefficient K ₂ and pulse width correction value τ ₁ is completed, the initial settings will be changed when the fuel injection start timing arrives. This outputs a fuel injection control pulse with a pulse width of

FIG. 4 shows the operation flow of the conventional example. As shown in FIG. 4, the starter switch 12
When turned on, first, in step a, information corresponding to various input information I ₁ , I ₂ , I ₃ , I ₄ , I ₅ and the fuel injection control pulse width are initialized. Next, in step b, it is determined whether or not it is fuel injection timing. If it is determined that it is fuel injection timing, in step c, intake pipe pressure information I ₁ and rotation speed information I to be input in synchronization with the fuel injection timing are input. ₂ is taken in, and the basic injection amount τ ₀ is calculated from this information I ₁ and I ₂ . When the calculation of the basic injection amount τ ₀ is completed, in step d, it is possible to calculate the pulse width τ of the fuel injection control pulse. In other words, the correction coefficients K ₁ and K ₂ of the above formula necessary to calculate the pulse width τ and the pulse It is determined whether the calculation of the width correction value τ ₁ has been completed, and if it is determined that the calculation of K ₁ , K ₂ , τ ₁ has been completed, the pulse width τ of the fuel injection control pulse is determined in step e. Calculation (τ=τ ₀
×K ₁ ×K ₂ +τ ₁ ), and outputs the fuel injection control pulse with the calculated pulse width τ to the fuel injection device 5, and the calculation of K ₁ , K ₂ , and τ ₁ is completed in step d. If it is determined that there is no fuel injection control pulse, the fuel injection control pulse having the pulse width initially set in step a is output to the fuel injection device 5 in step f. step e
Or, when step f is completed, in step g, water temperature information I ₃ , intake temperature information I ₄ , and throttle valve opening information I ₅ are taken in asynchronously with the fuel injection timing, and these pieces of information I ₃ , I ₄ , I ₅ , the water temperature correction coefficient K ₁ , intake temperature correction coefficient K ₂ and pulse width correction value τ ₁ are calculated. The correction coefficients K ₁ and K ₂ and the pulse width correction value τ ₁ calculated in step g are then used to calculate the fuel injection control pulse τ in step e. If it is determined in step b that it is not the fuel injection timing, the process proceeds to step g, where the input information I ₃ , I ₄ , I ₅ is taken in, and the correction coefficients K ₁ , K ₂ and pulse width correction value based on these input information are determined. This is to calculate τ ₁ .

FIG. 3 shows the operation of the above conventional example. Third
As shown in the figure, in the conventional example, at the first fuel injection timing TDC1 immediately after the starter switch 12 is turned ON, a fuel injection control pulse _P1 having an initially set pulse width is output to inject fuel into the third cylinder. Fuel is injected from the device, and each fuel injection timing from the second time onwards is TDC2, TDC3, TDC4, TDC5...
Here, fuel injection control pulses P ₂ , P ₃ , P ₄ , and P ₅ having the calculated pulse widths are output to the fuel injection device of each cylinder to perform fuel injection.

In addition, conventionally, immediately after turning on the starter switch 12, the pulse width of the fuel injection control pulse is initialized without initializing the various input information I ₁ , I ₂ , I ₃ , I ₄ , I ₅ . A method is also known in which a fuel injection control pulse with an initially set pulse width is output at the second fuel injection timing, and a fuel injection control pulse with the calculated pulse width is output at the second and subsequent fuel injection timings.

Problems to be Solved by the Invention However, the above conventional example has the following problems.

(1) When various input information is initialized immediately after the starter switch is turned on, and the pulse width of the fuel injection control pulse is calculated and output based on the initialized input information, the pulse width is the basis for the pulse width calculation. Since the various input information that is used is the initial setting value, the fuel injection control pulse width does not show good startability under all engine operating conditions or in all natural environments, which is one of the reasons why startability does not improve. become.

(2) When initially setting the pulse width of the fuel injection control pulse itself, it is similarly difficult to improve startability under all engine operating conditions and natural environments.

(3) In order to initialize various input information or the pulse width of the fuel injection control pulse, it is necessary to store the initial setting values in memory, and a program is required to process the initial settings. Therefore, memory capacity increases.

The present invention solves the above-mentioned conventional problems, and aims to reduce memory capacity while maintaining startability.

Means for Solving the Problems In order to achieve the above object, the present invention inputs all the engine parameters necessary for calculating the first fuel injection control pulse width immediately after turning on the power by the starter switch, and inputs the engine parameters. Until the calculation of the fuel injection control pulse width based on the engine parameters is completed, the output of the fuel injection control pulse is prohibited even though it is the fuel injection timing, and after the calculation of the fuel injection control pulse width based on the engine parameters is completed. , a fuel injection control pulse having a pulse width based on a calculation result is output at the fuel injection timing.

Effects The present invention has the above-described configuration, and can be used immediately after turning on the starter switch, that is, when engine parameters from various sensors are not input, or when calculating the pulse width of the fuel injection control pulse based on the engine parameters. If this is not possible, the fuel injection control pulse is not output based on the initial setting value, and after the calculation of the pulse width of the fuel injection control pulse based on various engine parameters is completed, the fuel injection control pulse is output at the fuel injection timing with the pulse width based on the calculation result. It outputs an injection control pulse, and after the starter switch is turned ON, it outputs a fuel injection control pulse based on the calculation results only after the calculation of the pulse width based on various engine parameters is completed, so it is completely natural under all engine operating conditions. The memory capacity can be reduced by eliminating the need to hold initial setting values without reducing startability under different circumstances.

Embodiment An embodiment of the present invention will be described below with reference to FIG. The configuration of the fuel injection control device that implements the fuel control method of this embodiment is the same as that of the conventional example shown in FIG. As shown in FIG. 1, in this embodiment, after the starter switch 12 is turned on, it is first determined in step a whether or not it is fuel injection timing. If it is determined in step a that it is fuel injection timing, then in step b, engine parameters to be taken in at the fuel injection timing, that is, intake pipe pressure information I ₁ from the intake pipe pressure sensor 7 are determined.
Then, the rotation speed information I ₂ from the rotation speed sensor 8 is taken in and the basic injection amount τ ₀ is calculated. Next, in step c, the engine parameters I ₃ , I ₄ , I ₅ necessary to calculate the pulse width τ of the fuel injection control pulse are taken in, and the correction coefficients K ₁ , K ₂ and the pulse width correction value τ ₁ are taken in. It is determined whether the calculation is completed. When it is determined in step c that the pulse width τ of the fuel injection control pulse can be calculated, the process proceeds to step d, where the pulse width τ of the fuel injection control pulse is calculated (τ=τ ₀ ×K ₁ ×
K ₂ +τ ₁ ) and send the calculated results to the fuel injection device 5.
Output to. Next, proceed to step e, take in engine parameters I ₃ , I ₄ , I ₅ and calculate correction coefficients K ₁ , K ₂ and pulse width correction value τ ₁ based on these engine parameters, and then proceed to step a. return. If it is determined in step c that the pulse width τ of the fuel injection control pulse cannot be calculated, the process proceeds to step e.

As shown in FIG. 1, in this embodiment, after the starter switch 12 is turned on and before the first fuel injection timing comes, steps a→e
→Repeat a..., engine parameters I ₃ , I ₄ , I ₅
and calculation of correction coefficients K ₁ , K ₂ and pulse width correction value τ ₁ based on these engine parameters. When it comes to the first fuel injection timing,
Proceeding from step a to step b, the engine parameters I ₁ and I ₂ are taken in and the basic injection amount τ ₀ is calculated. In the next step c, it is determined whether a state has been reached in which the pulse width τ of the fuel injection control pulse can be calculated (τ=τ ₀ ×K ₁ ×K ₂ +τ ₁ ). At the first fuel injection timing, step b→c
The engine parameters at step b
If the import of I ₁ , I ₂ or the calculation of the basic injection amount τ ₀ has not been completed, or the import of the engine parameters I ₃ , I ₄ , I ₅ or the correction coefficients K ₁ , K ₂ in step e,
If the calculation of the pulse width correction value τ ₁ has not been completed, the determination in step c is "NO" and the process moves to step e, skipping step d, so that the fuel injection control pulse is not injected. It turns out.
Since the rotation speed is low when the starter switch is ON, even if fuel injection is not normally performed at the first fuel injection timing, the determination in step c at the second fuel injection timing is "YES".
In step d, the pulse width τ of the fuel injection control pulse is calculated, and the fuel injection control pulse having the pulse width τ based on the calculation result is output to the fuel injection device 5.

In this way, in this embodiment, the starter switch
Even at the first fuel injection timing after ON, the fuel injection control pulse with the initially set pulse width is not output, and the calculation is performed once the calculation of the pulse width of the fuel injection control pulse is completed. It outputs a fuel injection control pulse with a pulse width τ based on the result, and the pulse width of the first fuel injection control pulse injected after the starter switch is turned on is a pulse width that reflects the engine condition, improving startability. There is no decrease in In addition, in this embodiment, there is no need to store in memory the initial setting values necessary for injecting fuel immediately after the starter switch is turned on, and a program for initial setting processing is not required, so the memory capacity can be reduced. It is.

Effects of the Invention The present invention has the above-mentioned configuration, and immediately after the starter switch is turned on, a fuel injection control pulse with a pulse width based on the initial setting value is not output, but a fuel injection control pulse with a pulse width based on the engine parameters is output. In order to generate output, fuel injection that reflects the engine status is performed immediately after the starter switch is turned on, reducing memory capacity while maintaining startability.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing a fuel injection control method in an embodiment of the present invention, Fig. 2 is a schematic diagram of a conventional fuel injection control device for an automobile, Fig. 3 is an explanatory diagram of the operation of the same device, and Fig. 4 is a flowchart showing the fuel injection control method of the device. 1... Engine, 2... Intake pipe, 3... Throttle body, 4... Throttle valve opening sensor, 5
... Fuel injection device, 6 ... Intake temperature sensor, 7 ...
Intake pipe pressure sensor, 8... Rotation speed sensor, 9...
Cylinder discrimination sensor, 10...Water temperature sensor, 11...
Battery voltage detection circuit, 12... Starter switch, 13... Engine control unit.

Claims (1)

[Claims] 1 Immediately after the power is turned on by the starter switch, fuel injection is not performed until the input of all engine parameters required for the first calculation of the fuel injection control pulse width and the calculation of the fuel injection control pulse width based on the engine parameters are completed. After the fuel injection control pulse width calculation based on the engine parameters is completed, the fuel injection control pulse output with the pulse width based on the calculation result is prohibited at the fuel injection timing. A fuel injection control method characterized by outputting an output.