JP3094484B2 - Engine fuel injection control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for an engine, and more particularly, to a detection signal of an air amount measured by an air flow meter and calculating a load corresponding to the air amount. The present invention relates to a fuel injection amount control device for an engine that calculates values of a fuel injection amount and an ignition timing from a search table including a load and an engine speed.

[0002]

2. Description of the Related Art Some vehicle engines are equipped with an electronic fuel injection control device as a measure against problems such as exhaust gas harmful components and fuel consumption rate. Some fuel injection control systems utilize the fact that the amount of air taken by the engine per cycle is substantially proportional to the absolute pressure in the intake manifold. In such a type of fuel injection control device, the fuel injection amount is set according to various conditions such as the intake pressure and the engine speed.

As disclosed in Japanese Patent Application Laid-Open No. Sho 62-170745, an engine control device measures the amount of intake air to the engine and the number of revolutions of the engine as operating conditions of the engine. An engine control device having a microcomputer circuit for supplying a fuel amount corresponding to the intake air amount and the engine speed has a delay element in the means for calculating the fuel amount with respect to the intake air detection amount during acceleration. It is a thing.

Further, as disclosed in Japanese Patent Application Laid-Open No. 1-280648, other fuel injection amount control devices for an engine include an air amount sensor for detecting the amount of air passing upstream of a throttle valve, and an engine rotation sensor. A rotational speed sensor for detecting several speeds, an air-fuel ratio sensor for detecting the engine air-fuel ratio, a delay element calculating means for obtaining a delay element having a magnitude corresponding to a deviation between the target air-fuel ratio and the engine air-fuel ratio, and a delay element. A fuel injection time calculating means for calculating a fuel injection time delayed from a fuel injection time obtained from an air amount sensor output and a rotational speed sensor output, and a fuel injection amount based on the fuel injection time calculated by the calculating means. And a fuel injection amount control means for controlling the fuel injection amount.

[0005]

Conventionally, in a fuel injection amount control device for an engine, a detection signal of an air amount measured by an air flow meter is input, and a load corresponding to the air amount is calculated. Calculating means for calculating the values of the fuel injection amount and the ignition timing from a search table comprising the determined load and the engine speed, and the calculating means replaces the air amount measured by the air flow meter with the engine load. Thus, the values of the fuel injection amount and the ignition timing are searched as they are from the search table and determined.

For this reason, when the intake throttle valve is rapidly opened during acceleration of the vehicle, the amount of air that is actually larger than the amount of air actually drawn into the cylinder is affected by the flow of air drawn into the intake passage. Since the amounts are measured, optimal fuel injection amounts and ignition timing values cannot be obtained at the time of acceleration of the vehicle, and there is a disadvantage that acceleration performance is reduced, drivability is deteriorated, and this is disadvantageous in practical use.

[0007]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention calculates a load corresponding to the amount of air by inputting a detection signal of the amount of air measured by an air flow meter, and calculates the load. In a fuel injection amount control device for an engine having calculation means for calculating values of a fuel injection amount and an ignition timing from a search table composed of a set load and an engine speed, a load is determined based on an air amount measured by the air flow meter. Calculate, calculate the load change amount of the calculated load at regular time intervals, calculate the throttle opening change amount corresponding to the calculated load change amount, and calculate the calculated throttle opening change amount. At the time of acceleration that is larger than the fixed amount and the calculated load change amount becomes a positive value, a correction value that changes according to the throttle opening and the throttle opening change amount By using the correction value that varies Flip,
The calculated load value is maintained or reduced.

[0008]

According to the present invention, a load is calculated based on the amount of air measured by an air flow meter, a load change amount of the calculated load is calculated at regular time intervals, and the load change amount is calculated in accordance with the calculated load change amount. The amount of change in the throttle opening is calculated to be greater than a predetermined amount, and when the calculated load change is a positive value, the correction is changed in accordance with the throttle opening. Value and a correction value that changes according to the throttle opening change amount,
Since the calculated load value is maintained or reduced, the optimal fuel injection amount and ignition timing value are obtained during vehicle acceleration, and the mixture and ignition timing are optimized to improve the acceleration performance. Therefore, good drivability can be maintained, which is practically advantageous.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 7 show an embodiment of the present invention. In FIG. 2, 2 is an engine, 4 is an intake passage,
6 is an exhaust passage.

An air cleaner 8 and an air flow meter 10 are provided upstream of the first intake passage 4-1.
Downstream of the first intake passage 4-1 is a second intake passage 4-2 downstream of the throttle body 14 having the intake throttle valve 12.
Is in communication with The second intake passage 4-2 communicates with a third intake passage 4-3 formed in the intake manifold 16. The third intake passage 4-3 communicates with the combustion chamber 20 of the internal combustion engine 2 via the intake valve 18.

An ignition plug (not shown) is provided in the combustion chamber 20.
And the exhaust passage 6 communicates via an exhaust valve 22.

A fuel injection valve 24 is mounted on the intake manifold 16 so as to face the combustion chamber 20. The fuel in the fuel tank 28 is fed under pressure to the fuel injection valve 24 through a fuel supply pipe 26. In the middle of the fuel supply pipe 26, a fuel pressure regulator 30 for regulating the pressure of the fuel is provided. The fuel injection valve 24 is driven by a fuel pump 32 provided in a fuel tank 28 so that the fuel supply pipe 2
The fuel in the fuel tank 28 is fed by pressure to the fuel tank 6. In the middle of the fuel supply pipe 26, a fuel filter 34 is provided. Further, the fuel pressure regulator 30 is connected to a pressure regulating passage 36 that opens into the fuel in the fuel tank 28.

The second intake passage 4-2 and the fuel tank 28 are communicated with each other by an evaporative fuel passage 38. A canister 40 and a two-way valve 42 are provided in the middle of the evaporative fuel passage 38 in this order from the second intake passage 4-2 side.

An intake throttle valve 12 is provided in the second intake passage 4-2.
Is provided. The bypass passage 44 is provided with an idle air amount control valve 46. The idle air amount control valve 46 stabilizes the idle rotation speed by opening and closing the bypass passage 44 to open and close the bypass passage 44 at the time of starting, at a high temperature, and when an adjustment of the idle rotation speed is required due to an increase in electric load. It is to let. Reference numeral 48 denotes a switching valve for power steering, and reference numeral 50 denotes an air regulator.

The above-mentioned spark plug is for sparking the high voltage generated by the ignition coil 52, which is distributed and supplied by the distributor 54.

Fuel injection valve 24, idle air amount control valve 4
6. The power steering switching valve 48 and the ignition coil 52 are connected to the control unit 56. The ignition coil 52 is connected to the control unit 56 via a power unit 58. The control unit 56 includes an air flow meter 10 for detecting an intake air amount, a water temperature sensor 62 for detecting a temperature of a cooling water in a cooling water passage 60, a knock sensor 64 for detecting the occurrence of knock, and an intake throttle valve 12. A throttle sensor 66 for detecting the opening degree state, an oxygen concentration detection sensor 70 provided in the exhaust passage 6 upstream of the catalytic converter 68 for detecting the oxygen concentration in the exhaust gas, a vehicle speed sensor 72 for detecting the engine speed, and a crank angle Various sensors and devices such as a crank angle sensor 74 to be detected are connected. Reference numeral 76 denotes a battery, 78 denotes a main switch, 80 denotes a thermofuse, 82 denotes an alarm relay, and 84 denotes a warning light.

The control unit 56 includes an air flow meter 10
A load signal corresponding to the air amount is calculated by inputting a detection signal of the air amount measured according to (1), and a fuel injection amount and an ignition timing are obtained from a search table (see FIG. 4) including the calculated load and the engine speed. It has a function as a calculating means for calculating a value, calculates a load based on the amount of air measured by the air flow meter 10, calculates a load change amount of the calculated load at regular time intervals, and calculates the load. A throttle opening change amount corresponding to the calculated load change amount is calculated, and at the time of acceleration when the calculated throttle opening change amount is larger than a predetermined amount and the calculated load change amount becomes a positive value,
The calculated load value is maintained or reduced by using a correction value that changes according to the throttle opening and a correction value that changes according to the throttle opening change amount.

More specifically, when the air flow meter 10 measures the amount of air sucked into the intake passage 4, the air flow meter 10 outputs a detection signal corresponding to the measured amount of air, and 56 receives the detection signal from the air flow meter 10 and replaces the measured air amount (see FIG. 3) with a search load y as a load to calculate (calculated by the air flow meter 10 in FIG. 6). Actual load shown).

As shown in FIG. 6, the calculated search load y is calculated at regular time intervals ta, whereby the load change amount (yb-ya) of the search load y is calculated. You.

At this time, the calculated load change amount (y
b-ya), the throttle opening change amount ΔTH corresponding to the calculated load change amount (yb-y) is calculated.
The throttle opening change amount ΔTH within a fixed time in the past corresponding to a) is monitored. When the throttle opening change amount ΔTH is smaller than a predetermined amount (offset amount) α, the final search load ynew is set as the search load y (y
new = y).

On the other hand, the vehicle acceleration in which the throttle opening change amount ΔTH is larger than a predetermined amount (offset amount) α and the calculated load change amount (yb-ya) becomes a positive value (yb-ya> 0) Sometimes, a correction value that changes according to the throttle opening (correction 1: x1 in FIG. 5) and a correction value that changes according to the throttle opening change amount ΔTH (correction 2: x2 in FIG. 5)
Is used to maintain or reduce the value of the above-described search load y, the final search load (shown by the corrected load in FIG. 6) ynew is calculated as follows: ynew = y + (yb−ya) × (x1 + x2) ) / 2.

However, at the time of deceleration of the vehicle in which the load change amount (yb-ya) is a negative value (yb-ya <0), the final search load ynew is smaller than the search load y (ynew < y), as described above, the final search load y
new is set as a search load y (ynew = y).

Using the final search load ynew, the values of the fuel injection amount and the ignition timing are calculated from a search table (see FIG. 4) including the search load y and the engine speed. The value of the ignition timing is corrected and controlled from an improper state (shown by a solid line in FIG. 3) to an appropriate state (shown by a broken line in FIG. 3). The aim is to optimize

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

When the program of the controller 56 is started (step 100), the air flow is measured by the air flow meter 10 (step 102), and the load is determined based on the air flow measured by the air flow meter 10 (see FIG. 3). Is calculated every fixed time ta, and the load change amount (yb−y) of the search load y is calculated.
a), and at the same time, the throttle opening change amount ΔT corresponding to the calculated load change amount (yb-ya).
H is calculated, and the throttle opening degree change amount ΔTH within the past fixed time corresponding to the load change amount (yb-ya) is monitored (step 104). Then, it is determined whether the calculated throttle opening change amount ΔTH is positive (+), that is, whether the change in the throttle opening is in the opening direction (step 1).
06).

If the answer to step 106 is NO and the throttle opening change ΔTH is negative (−), that is, if the change in throttle opening is in the closing direction, the vehicle is being decelerated, so the final search load ynew Is the search load y (y
new = y) (step 108).

On the other hand, if step 106 is YES and the throttle opening change amount ΔTH is positive (+), it is determined whether the throttle opening change amount ΔTH is larger than a predetermined amount (offset amount) α. (Step 110). If this step 110 is NO, the final search load ynew
Is the search load y (ynew = y) (step 10).
8).

If step 110 is YES,
As shown in FIG. 6, a load change amount (yb-ya) per predetermined time (ta) of the search load y is calculated (step 11).
2).

Then, it is determined whether or not the load change amount (yb-ya) is a positive value (yb-ya> 0) (step 114). If this step 114 is NO and the load change amount (yb-ya) is a negative value (yb-ya <0) (see FIG. 7), the final search load ynew is changed to the search load y.
It is determined whether or not (ynew ≧ y) (Step 1)
16). If step 116 is NO, the final search load ynew is set to the previous search load yold (step 118). If step 116 is YES, the final search load ynew is set to the search load y. (Y = new) (step 108).

If the determination in step 114 is YES and the load change amount (yb-ya) is a positive value (yb-ya> 0), it means that the vehicle is accelerating, and the change is made according to the throttle opening. Using the correction value (correction 1: x1 in FIG. 5) and the correction value (correction 2: x2 in FIG. 5) that changes according to the throttle opening change amount ΔTH, the final search load ynew is calculated as follows: ynew = y + It is calculated by (yb-ya) × (x1 + x2) / 2 (step 120).

The final search load ynew and the final search load ynew from the above-described step processing (steps 108 and 118) are less than the maximum load value ymax (see FIG. 5) of the search load y (see FIG. 5). ynew <
ymax) is determined (step 122).

If this step 122 is NO, the values of the fuel injection amount and the ignition timing are calculated from the search table (see FIG. 4) using the value of the final search load ynew (step 126).

On the other hand, if step 122 is YES, the load ynew for the final search is made equal to the maximum load value ymax as the guard value (ynew = ymax) (FIG. 5).
(See step 124), this final search load yne
The value of w and the value of the fuel injection amount and the value of the ignition timing are calculated from the search table (see FIG. 4) (step 126). This control is repeated until the engine 2 stops (step 128).

As shown in FIG. 3, when the intake throttle valve 12 is suddenly opened during acceleration of the vehicle, the intake air is actually drawn into the cylinder due to the flow of air drawn into the intake passage 4. The air-fuel mixture (shown by the solid line in FIG. 3), which is measured more than the required amount of air and is richer than the required amount, is subjected to the required concentration by the above-described fuel injection amount correction control. The ignition timing (indicated by a solid line in FIG. 3) that is retarded from the required ignition timing can be requested by the above-described correction control of the calculated ignition timing. Since the ignition timing can be advanced to the ignition timing (indicated by the broken line in FIG. 3), the driver can optimize the air-fuel mixture and optimize the ignition timing during acceleration of the vehicle to improve the acceleration performance, Ability to maintain good , As well as a practically advantageous, and give improved fuel consumption rate of the engine 2 can be economically advantageous.

[0036]

As described above in detail, according to the present invention, a load is calculated based on the amount of air measured by an air flow meter, and a load change amount of the calculated load at regular time intervals is calculated. A throttle opening change amount corresponding to the calculated load change amount is calculated. When the calculated throttle opening change amount is larger than a predetermined amount and the calculated load change amount becomes a positive value, the throttle opening is calculated. By using the correction value that changes according to the opening and the correction value that changes according to the amount of change in the throttle opening to maintain or reduce the calculated load value, optimal fuel injection is achieved during vehicle acceleration. By obtaining the values of the amount and the ignition timing, the mixture and the ignition timing can be optimized, the acceleration performance can be improved, the drivability can be maintained favorably, and this is practically advantageous.

[Brief description of the drawings]

FIG. 1 is a flowchart of a fuel injection amount control.

FIG. 2 is a system configuration diagram of a fuel injection amount control device.

FIG. 3 is a time chart of fuel injection amount control.

FIG. 4 is a search table including a load and an engine speed;

FIG. 5 is a diagram showing correction values and guard values.

FIG. 6 is a diagram showing a load change amount of a search load.

FIG. 7 is a diagram showing a change state of a load.

[Explanation of symbols]

 2 Engine 4 Intake passage 6 Exhaust passage 8 Air cleaner 10 Air flow meter 12 Intake throttle valve 14 Throttle body 16 Intake manifold 24 Fuel injection valve 30 Fuel pressure regulator 46 Idle air amount control valve 48 Power steering switching valve 52 Ignition coil 56 Control unit (Calculation means) 62 Water temperature sensor 66 Throttle sensor 70 Oxygen concentration detection sensor 72 Vehicle speed sensor 74 Crank angle sensor

Claims (1)

(57) [Claims] We claim: 1. Enter the detection signal of the air amount that is metered by the air flow meter calculates the load corresponding to the amount of air, from the search <br/> search table of the calculated load and the engine speed Calculate values of fuel injection amount and ignition timing
In the fuel injection amount control device for an engine having calculation means , based on the air amount measured by the air flow meter ,
There is calculated the load, calculates a load change amount per predetermined time of the calculated load, to calculate the throttle opening change amount corresponding to the calculated load variation, the calculated scan <br / > throttle opening change amount is large and the calculation than a predetermined amount
When the load change amount becomes a positive value during acceleration , the correction value that changes according to the throttle opening and the throttle opening change
Using the correction value that changes according to the amount of
A fuel injection amount control device for an engine, characterized in that the value of the load is maintained or reduced .