JP2500946Y2 - Electronically controlled fuel supply system for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electronically controlled combustion supply device for an internal combustion engine suitable for both fuel injection specifications and carburetor specifications.

[Prior art]

Conventionally, as this type of electronically controlled fuel supply device, for example, there is one described in Japanese Patent Application Laid-Open No. 57-203827.

In this device, the load discriminator determines that the load on the engine is greater than or equal to a predetermined value, and the throttle valve opening detection means detects the throttle valve opening that is not affected by pulsation. The supply amount is increased / decreased according to the opening degree of the throttle valve.

[Problems to be solved by the invention]

In such a conventional electronically controlled material supply device, the starting point of full fuel increase is managed by the absolute value of the detection value of the throttle valve opening detection means.

However, the throttle valve opening detection means (sensor) varies from engine to engine during the initial setting of the engine. Also,
Since the throttle valve controls the engine output, its fully opened opening is made to be constant with high accuracy, but the idle opening is adjusted so that it becomes a predetermined idle speed for each engine with different friction. Therefore, the stroke amount from the idle opening of the throttle valve to the fully open opening varies from engine to engine.

Therefore, in consideration of variations at the initial setting of the throttle valve opening detection means and variations in the stroke amount of the throttle valve,
There is no choice but to set the throttle valve full increase start opening to a low value, which causes a large amount of full increase in the majority of engines early, resulting in deterioration of engine fuel consumption and exhaust gas.

The present invention aims to solve such conventional problems.

[Means for solving problems]

Therefore, the electronically controlled fuel supply system for an internal combustion engine according to the present invention, as shown in the functional block diagram of FIG. 1, has a throttle valve opening detecting means A for detecting the throttle valve opening and the throttle valve opening detecting means. A stroke amount calculation means B for calculating the stroke amount from the idle opening of the throttle valve based on the throttle opening and the idle opening detected by A, and a throttle valve opening value for starting the increase of the supplied fuel amount. And an increase opening setting means C for setting the calculated stroke amount, and when the calculated stroke amount exceeds a predetermined maximum value, the maximum value is updated by the calculated stroke amount, and the stroke amount corresponding to the maximum value excess amount is increased. Setting value changing means D for increasing the opening setting value, and fuel increasing means E for increasing the supplied fuel when the throttle valve opening detected by the throttle valve opening detecting means is larger than the increasing opening setting value. With was.

[Action]

With this configuration, the starting point of full fuel increase can be controlled according to the stroke amount from the idle opening of the throttle valve, and thus the full increase can be optimized for each engine according to the characteristics of the engine. It becomes possible to do.

〔Example〕

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

 FIG. 2 is a block diagram showing an embodiment of the present invention.

In the figure, 1 is an internal combustion engine of fuel injection specification (hereinafter, simply referred to as “engine”), 2 is an electromagnetic fuel injection valve, which injects fuel toward an intake port 3.

An O ₂ sensor 4 detects the oxygen concentration in the gas exhausted from the engine 1 via the exhaust port 5 and the exhaust manifold 6.

Reference numeral 7 is an exhaust pipe, 8 is a three-way catalytic converter, and 9 is a water temperature sensor for detecting the cooling water temperature of the engine 1.

10 is the intake manifold, 11 is the throttle chamber, 12
Is a throttle valve, and 13 is a throttle valve opening sensor that detects the opening degree of the throttle valve 12 with good responsiveness.

As the throttle valve opening sensor 13, for example, a rheostat whose resistance value changes according to the opening position of the throttle valve 12 can be used.

An air flow meter 14 detects an intake air amount corresponding to the load of the engine 1. Reference numeral 15 is an air cleaner, and 16 is a crank angle sensor, which outputs various pulse signals corresponding to the crank angle and the rotation speed according to the rotation of the engine 1.

17 is a control unit, which is a central processing unit (CP
U) 18, data memory (RAM) 19, program memory (RO
M) 20, non-volatile memory (NVM) 21 backed up by a battery (not shown), and A / D, D / A converter, fuel injection valve drive circuit, rotation speed detection circuit (pulse from crank angle sensor 16) The system is configured by an input / output interface circuit (I / F) 22 composed of (detected by a signal).

And this control unit 17 has its CPU 18
The stroke amount calculating means shown in FIG. 1 according to the present invention by processing an input signal from each sensor while sequentially executing a program stored in the ROM 20 to be described later.
The engine 1 has various functions of B, the increasing opening setting means C, the set value changing means D, and the fuel increasing means E.
It controls various control functions (for example, control of the air-fuel ratio and ignition timing) necessary for the operation of.

The operation of the embodiment configured as described above will be described with reference to the flow charts of FIGS. 3 and 4.

First, referring to the flow chart of the basic processing routine of the fuel injection amount control shown in FIG. 3, the CPU 18 sends the water temperature sensor 9, the throttle valve opening sensor 13, and the air flow meter 14 from the I / F 22 at step 1. The cooling water temperature data Tw, the throttle valve opening data θ, and the intake air amount data (load data) Q are read, as well as the rotational speed data N sequentially obtained by the I / F 22.

Next, in step 2, the intake air amount data Q, the rotational speed data N read in step 1, and the constant K stored in advance in the ROM 20.
Based on, the basic fuel injection amount Tp is calculated by calculating Tp = K · Q / N.

Then, in Step 3, the throttle valve opening degree data θ and the throttle valve opening degree setting value θF (details will be described later) stored in the nonvolatile memory 21 for starting the increase of the injected fuel (full increase) are compared with each other. If .theta.>. Theta.F, the operation proceeds to step 4 to perform an increase (full increase) correction, and if .theta.>. Theta.F, the operation proceeds to step 5 to perform no increase correction.

In the normal processing in which the increase correction in step 5 is not performed, the mixture ratio correction coefficient COEF is obtained by the following calculation.

COEF = 1 + KMR + KTw However, KMR is a mixture ratio allocation coefficient, which is stored in the ROM 20, and KTw is a water temperature correction coefficient, which is obtained by, for example, table cooling up the data table in the ROM 20 with the cooling water temperature data Tw.

In the increase correction process of step 4, the CPU 18 calculates the mixture ratio correction coefficient COEF by the following calculation.

COEF = 1 + KMR + KFUL + KTw where KFUL is the full (fully open) increase coefficient, which is the data stored in ROM20.

Next, in step 6, the mixture ratio correction coefficient COEF obtained in any of the above processes, the basic fuel injection amount Tp obtained in step 2, and the battery voltage correction coefficient Ts not shown Injection amount data Ti (pulse width data)
Is calculated (Ti = Tp · COEF + Ts), and the Ti is calculated in step 7.
A signal is output to control the valve opening of the fuel injection valve 2, and the processing of this routine ends.

The fuel injection control is performed by the CPU 18 periodically performing such routine execution processing in synchronization with the crank angle pulse signal from the crank angle sensor 16.

When the air-fuel ratio feed back control is performed based on the oxygen concentration data in the exhaust gas from the O ₂ sensor 4, the feed back coefficient is added to the calculation term of the mixture ratio correction coefficient COEF.

Next, a routine for correcting and changing the throttle valve opening set value θF in step 3 of FIG. 3 will be described with reference to the flowchart of FIG.

This routine is also executed periodically in synchronization with the crank angle pulse signal from the crank angle sensor 16, and the CPU 18 makes the engine start flag NN at the first step 10.
Check if is zero or not.

This flag NN is set to zero only when the power of the control unit 17 is turned on, and if NN is determined to be zero in the above check, it means that the engine 1 has started for the first time, and therefore, at step 11. The maximum value SM of the stroke amount of the throttle valve 12 is stored in the ROM 20 in advance and the initial value S
After setting it to M ₀ and storing it in the nonvolatile memory 21, in step 12, the flag NN is set to "1".

If the NN is judged to be "1" at step 10, it means that the engine 1 has already been started and the processing for setting SM to SM ₀ has been executed, so steps 11 and 12 are skipped.

Next, in step 13, the current throttle valve opening data θ from the throttle valve opening sensor 13 is read in via the I / F 22.

Then, based on the throttle valve opening data θ and the idle opening data θI read in step 14, the current stroke amount ST from the idle opening θI of the throttle valve 12 is ST =
It is calculated by θ−θI.

As the idle opening data θI, a fixed value stored in advance in the ROM 20 may be used, or a learning control value of the idle opening by a known method may be used.

Next, at step 15, the magnitude of the current stroke amount ST and the maximum value SM (SM ₀ or the value updated so far) of the stroke amount of the throttle valve 12 stored in the non-volatile memory 21 is determined. , ST> SM, the processing of this routine is immediately terminated without changing the throttle valve opening set value θF.

If ST> SM, the process proceeds to the next step 16 and the difference ΔS (ΔS = ΔS = ΔS = Δ) between the current stroke amount ST and the maximum value SM up to now.
After calculating ST-SM), in the next step 17, the throttle valve opening set value θF indicating the throttle valve opening for starting the above-mentioned increase in injected fuel (full increase) stored in the nonvolatile memory 21 Then, the value obtained by adding the difference ΔS obtained in step 16 is stored as a new θF.

However, the initial value of this θF is the nonvolatile memory 21 or
It is assumed that the ROM20 is programmed in advance.

Then, in step 18, the maximum value of the stroke amount so far
The SM is replaced with the current stroke amount ST (ST> SM), and the processing of this routine is completed.

By thus regularly executing the routine processing, the optimum throttle valve opening setting value θF is always determined,
By executing the above-described fuel injection control routine of FIG. 3 based on that, the fuel amount during acceleration (full fuel increase) is increased.
Is optimally performed as required by the engine 1, and the fuel economy and exhaust emission do not deteriorate.

The main operation and effect of this embodiment will be further described with reference to FIGS. 5 and 6.

That is, when the program shown in FIG. 3 and FIG. 4 is executed, as shown in FIG. 5 (a), a full increase is made with θ> θF under the condition of ST ≦ SM, but actually the throttle valve 12 The stroke amount ST from the idle opening θI to the fully open opening may be larger than the opening stroke maximum value SM. If such a thing occurs this time, as shown in FIG. ΘF reset by adding ΔS to θF
From F, full increase will be made.

Therefore, as shown in FIG. 6, when θF remains fixed, the throttle valve opening larger than the boundary indicated by the solid line indicates that the throttle valve opening is larger than the boundary indicated by the broken line. The full increase is made only in the area a in the area b, and the area b from the broken line boundary to the solid line boundary
Not only can fuel efficiency be improved, but deterioration of exhaust emission can be prevented.

In the above-described embodiment, the fixed specifications in which θF is not changed according to the operating conditions (for example, the number of revolutions) of the engine 1 have been described, but as shown in FIG. If the speed is changed according to the rotation speed, the above effect is further improved.

Further, according to the above-mentioned embodiment, even if the throttle valve opening sensor 13 has a variation at the time of initial setting, it is possible to absorb the control error due to the variation.

Further, in the above embodiment, the example in which the invention is applied to the internal combustion engine of the fuel injection specification is described, but the invention can be similarly applied to the internal combustion engine of the electronic carburetor specification, and thereby the same effect can be obtained. Play.

〔effect〕

As described above, according to the present invention, the starting point of full fuel increase is controlled according to the stroke amount from the idle opening of the throttle valve. The fuel consumption and the exhaust emission can be improved accordingly.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an electronically controlled fuel supply device according to the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, and FIGS. 3 and 4 respectively show the CPU 18 of FIG. A flow chart of a program according to the present invention to be executed, and FIGS. 5 and 6 are explanatory diagrams for explaining the operation and effect by the embodiment of FIG. 2, respectively. 1 ... Internal combustion engine, 2 ... Fuel injection valve 9 ... Water temperature sensor, 12 ... Throttle valve 13 ... Throttle valve opening sensor 14 ... Air flow meter 16 ... Crank angle sensor 17 ... Control unit

Claims (1)

(57) [Scope of utility model registration request] Claim: What is claimed is: 1. A throttle valve opening detecting means for detecting a throttle valve opening; and an idle opening of the throttle valve based on the throttle valve opening and the idle opening detected by the throttle valve opening detecting means. Stroke amount calculation means for calculating the stroke amount of, the increase opening degree setting means for setting the throttle valve opening value for starting the increase of the supplied fuel amount, and the calculation when the calculated stroke amount exceeds a predetermined maximum value. Set value changing means for updating the maximum value with the stroke amount and increasing the increase opening setting value by the stroke amount corresponding to the excess of the maximum value, and the throttle valve detected by the throttle valve opening detecting means. An electronically controlled fuel supply device for an internal combustion engine, comprising: a fuel increasing means for increasing the supplied fuel when the opening is larger than the increase opening set value.