JPH0216346A - Fuel feed control method for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the fuel consumption and the acceleration responsibility by cutting a fuel based on the relation between the actual engine speed and the actual throttle valve opening, and releasing the fuel cut when the actual throttle valve opening is changed to the opening direction. CONSTITUTION:An injector for fuel injection provided on the inlet pipe 2 of an internal combustion engine 1 is controlled by an ECU 13 based on each detection signal from a distributor 8, a water temperature sensor 9, a throttle position sensor 11 and a vacuum sensor 12. In this case, the ECU 13 conducts a fuel cut when the relation between the actual engine speed and the actual throttle valve opening is moved from a fuel feed range preset based on said relation to a fuel cut range. It also releases the fuel cut when the actual throttle valve opening exceeds a return standard level of the throttle valve opening preset in the fuel cut range and is changed to the opening direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a fuel supply control method for controlling fuel supply in response to deceleration operation of an internal combustion engine.

[Prior Art] Conventionally, in an internal combustion engine, for example, a vehicle engine, when the engine rotation speed is above a predetermined set rotation speed and the throttle valve opening is below a predetermined set opening, the engine is stopped. It is known that the engine is considered to be decelerating and the fuel supply to the engine is cut off, that is, the fuel is cut to improve fuel efficiency.

Also, as this kind of thing, for example, as shown in Fig. 5,
It is also known that the setting level LO of the throttle valve opening θT11 for fuel cut determination is increased in accordance with the increase in engine rotation INe (for example, in Japanese Patent Application Laid-open No. 6
0-90936 and JP-A-60-212645).

On the other hand, in order to prevent a delay in the response of fuel resupply when changing from the above-mentioned fuel cut state, that is, deceleration operation to acceleration operation, the fuel cut is canceled when the throttle valve opening reaches the set opening or more. Things are also known (Tokuko Sho 60-25
(Disclosed in Publication No. 06).

Therefore, in order to perform fuel cut during deceleration operation and resupply fuel when changing from deceleration operation state to acceleration operation, for example, the relationship between throttle valve opening θTl+ and engine rotation speed Ne as shown in FIG. The based setting level LO will be used as a reference.

That is, the area above the set level LO becomes the fuel supply area A, and the area below the set level LO becomes the fuel cut area B.

[Problems to be Solved by the Invention] However, when determining fuel cut or fuel supply based on one setting level LO as in the past, there is a problem in setting the fuel cut region B and the fuel supply region A. was there.

That is, if the fuel cut-nff area B is widened in order to cut fuel as quickly as possible during deceleration operation, the fuel supply area A becomes narrower, causing a response delay in the timing of fuel resupply during acceleration operation, resulting in a reduction in the speed of acceleration operation. This resulted in the occurrence of motatsuki. Conversely, if the fuel supply area A is widened in order to resupply fuel as quickly as possible during acceleration, the fuel cut area B becomes narrower, resulting in a delay in response to fuel cut and worsening fuel efficiency. Ta.

The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a fuel supply control method for cutting fuel to an internal combustion engine based on engine speed and throttle valve opening. To provide a fuel supply control method for an internal combustion engine that can quickly carry out fuel capturing and moreover quickly resupply fuel when changing from deceleration operation to acceleration operation.

Means for Solving the Problems] In order to achieve the above object, the present invention provides a fuel supply side '4m11 method in which fuel is cut to the internal combustion engine based on the engine speed and the throttle valve opening. A fuel supply region and a fuel power range based on the relationship between engine speed and throttle valve opening are determined in advance, and the relationship between the actual engine speed and actual throttle valve opening is determined from the fuel supply region. Is the fuel cut when moving to the fuel cut area? A return reference level of the throttle valve opening is predetermined within the J range, and the fuel t4 cut is canceled when the actual throttle valve opening changes in the opening direction beyond this return reference level.

1. Therefore, the relationship between the actual engine speed and the actual throttle valve opening changes from the fuel supply region to the fuel cut region, so that fuel cut is immediately performed as deceleration operation.

On the other hand, when the actual throttle valve opening exceeds the return reference level and changes in the opening direction within the fuel cut region, the fuel cut is immediately canceled as a change from deceleration to acceleration. That is, before the actual throttle valve opening degree moves from the fuel power/7t range to the fuel supply range, the fuel power/7t is released.

[Embodiment 1] Hereinafter, an embodiment in which the present invention is embodied in an engine with an electronically controlled fuel injection device for a vehicle will be described in detail with reference to the drawings.

FIG. 2 is a schematic diagram of a fuel supply system to which the fuel supply control method of the present invention is applied. An intake pipe 2 and an exhaust pipe 3 are connected to an engine 1 serving as an internal combustion engine. Air taken in through the air cleaner 4 is drawn into the engine 1 through the intake pipe 2, and exhaust from the engine 1 is discharged through the exhaust pipe 3 and the catalyst 5.

An injector 6 for fuel injection is provided on the intake side of the engine 1, and is connected to a fuel pump (not shown). In addition, the engine l has an engine rotation speed N as the engine rotation speed.
A distributor 8 is provided for detecting the rotation speed e and supplying discharge voltage to each spark plug 7 in synchronization with the detected rotation speed. Further, the engine 1 is provided with a water temperature sensor 9 for detecting its cooling water temperature.

A throttle valve 10 is provided in the middle of the intake pipe 2. A throttle position sensor 11 is connected to the throttle valve 10 to detect the throttle valve opening θTH. Further, a vacuum sensor 12 for detecting intake pipe negative pressure is connected to a surge tank 2a in the middle of the intake pipe 2.

An electronic control unit (ECU) 13 for fuel supply control has a built-in memory. EC
U13 inputs detection signals from the water temperature sensor 9 and vacuum sensor 12, and outputs an injection signal to the injector 6 based on the detection signals to perform basic fuel injection amount control during engine startup and normal driving.

Further, the ECU 13 receives a detection signal of the engine rotation speed Ne detected by the distributor 8 and a throttle valve opening degree θTl detected by the throttle position sensor 11.
Based on these detection signals, the ECU 13 cuts fuel during deceleration operation of the engine 1, or resupplies fuel when changing from deceleration operation to acceleration operation. outputs a force control signal or injection signal to the injector 6.

That is, a two-dimensional map as shown in FIG. 1 is stored in advance in the memory of the ECU 13 as data. This map shows the engine speed Ne and the throttle valve opening θTl.
The throttle valve opening degree θTH of the setting level L1 is set to increase as the engine speed Ne increases.

Then, the same level L1 is set based on this set level L1.
The area above the set level L1 is set as a fuel supply area (area where fuel injection is permitted) A, and the area below the set level L1 is set as a fuel cut area (area where fuel injection is stopped) B. Furthermore, within the fuel cut region B, a return reference level L2 of the throttle valve opening θTl+ is predetermined. In this embodiment, the return reference level L2 is set to the engine rotation speed N.
It is assumed to be uniformly determined regardless of the size of e.

Further, the area below this return reference level L2 is set as the small fuel cut area C (the half fuel cut area C is included in the fuel cut area B).

Based on the detection signals from the distributor 8 and the throttle position sensor 11, the ECUI 3 determines the actual engine speed Ne and the actual throttle valve opening θT1.
When it is determined that the relationship with 1 has shifted from the fuel supply area A to the fuel cut area B, a force note signal is output to the injector 6 to perform fuel cut as deceleration operation.

Further, when the ECU 13 determines that the actual throttle valve opening θTl+ has exceeded the return reference level L2 and changed in the opening direction, the ECU 13 determines that the deceleration operation state has changed to acceleration operation and injects the injector in order to cancel the fuel cut. The injection signal is output to 6. In other words, when in a deceleration driving state,
The fuel cut is canceled and fuel is resupplied based only on the change in the throttle valve opening θTl+.

In the map of FIG. 1, another level L3 shown in the fuel supply area A shows the relationship between the engine rotational speed Ne and the throttle valve opening θT11 during no-load operation. It can be seen that the throttle valve opening degree θT11 increases as the engine speed Ne increases.

Next, the control operation of the ECU 13 will be explained according to the flowchart shown in FIG.

Now, in the starting state t)+ of the engine 1, first, in step 101, it is determined in which region A-C in the map the relationship between the throttle valve opening θTH and the actual engine speed Ne falls. , a detection signal is input from the distributor 8 and the throttle position sensor 11.

If the relationship between the actual engine speed Ne and the throttle valve opening θTl+ is in the fuel supply region A, the process proceeds to step 102 as a normal operating state, and an injection signal is sent to the injector 6 to supply fuel. Output. If the relationship between the throttle valve opening θT)I and the actual engine speed Ne is in the half-fuel cut region C, the process moves to step 103 as a deceleration operation state, and the injector 6 is cut off to perform a fuel cut. Output a signal.

On the other hand, is the relationship between the actual engine speed Ne and the throttle valve opening θTH a fuel cut? iJ (if it is in region B, the process moves to step 104. Then, whether the current acceleration operation state is in progress, that is, the throttle valve opening θTl
It is determined whether the minute change between + and the currently obtained throttle valve opening θTll is larger than a predetermined set value α, which exceeds the set level L1, for example.

If the minute change ΔθTl (is larger than the set value α, the process moves to step 102 as an accelerating operation state, and outputs an injection signal to the injector 6 to supply fuel. Also, the minute change ΔθTl+ is not larger than the set value α, step 10 is performed as a deceleration operation state.
Move to 3, fuel power.

do the following.

Subsequently, after fuel supply or fuel cut is performed in steps 102 and 103, the process moves to step 105 and the relationship between the throttle valve opening θTll and the actual engine speed Ne is determined in which region A to C. In order to determine whether this is the case, the detection signals from the distributor 8 and the throttle position sensor 11 are manually input.

If the relationship between the actual engine speed Ne and the throttle valve opening θTH is in the fuel supply region A, then
The process moves to step 106, and an injection signal is output to the injector 6 to continue fuel supply. Further, if the relationship between the actual engine speed Ne and the throttle valve opening θTll is in the semi-fuel cut region C, step 107
Then, a cut signal is output to the injector 6 to cut fuel during deceleration operation.

On the other hand, if the relationship between the throttle valve opening θTll and the actual engine speed Ne is in the fuel cut region B, the process moves to step 108, and the relationship between the throttle valve opening θTl+ and the previously input actual engine speed Ne It is determined in which area A to C the image is located.

If the previous region is the semi-fuel cut region C, then the actual throttle valve opening θTH has changed from the fuel cut region C to the return reference level L2 in the opening direction, and the engine 1 This means that the state has changed from the deceleration state to the acceleration state.Therefore, the process moves to step 106 to resupply fuel.In this case, the determination in step 108 is that the throttle valve opening θTl+ has reached the uniform return reference level L2. It is not necessary to make the engine speed Ne a determination requirement.

Further, if the previous region is the fuel supply region A, this means that the fuel supply region A has changed to the fuel cant region B, and the engine 1 has changed to deceleration operation. Therefore, the process moves to step 107 and a fuel cut is performed.

On the other hand, if the previous area is fuel cut area B,
Assuming that there is no change in the area, the process moves to step 109, and it is determined whether or not the previously obtained throttle valve opening θTl (and the minute change ΔθTl+ in the throttle valve opening θTl+ obtained this time) is larger than the set value α. Determine whether

If the minute change ΔθTi is larger than the set value α, the process moves to step 106 as an accelerated driving state and resupplies fuel. Moreover, the minute change ΔθT)I
If is not larger than the set value α, the process moves to step 107 as a deceleration operation state and continues the fuel cut.

As described above, in this embodiment, the relationship between the actual engine speed Ne and the actual throttle valve opening θTH exceeds the set level L1 as shown by the arrow a in FIG. ? When changing to J area B, fuel cut is immediately performed as deceleration operation.

As a result, fuel can be quickly cut during deceleration operation, and wasteful fuel consumption can be prevented and fuel efficiency can be improved.

On the other hand, as shown by the arrow in Figure 1, there is half fuel power.

When the actual throttle valve opening degree θTl+ exceeds the return reference level L2 and changes in the opening direction in the target region C, fuel is immediately resupplied as a change from deceleration operation to acceleration operation. That is, the fuel cut is quickly canceled before the actual throttle valve opening θTH exceeds the set level Ll and changes from the fuel cut region B to the fuel supply region A.

As a result, it is possible to prevent a delay in the response of fuel resupply when switching from a deceleration state to an acceleration state, thereby further improving the responsiveness of the acceleration state.

In addition, in this embodiment, in order to resupply fuel from a deceleration driving state to an acceleration driving state, as described above, the
Only the throttle valve opening θTl+ with respect to the standard bell L2 is set to 4'<44, and only the magnitude of the minute change ΔθTl (of the throttle valve opening θTH with respect to the set value α) is used as a reference. In other words, the engine rotation speed Fuel resupply is executed based only on the throttle valve opening θT11 regardless of Ne.Therefore, the calculation for fuel resupply sent to the ECU 13 is based only on the throttle valve opening θTl+. It can be done easily.

In the above embodiment, an engine with an electronically controlled fuel injection device for a vehicle is used, but the invention is not limited to this, and in short, the relationship between the actual throttle valve opening θTH and the actual engine speed Ne is It can be used as long as it is based on the system, and it can also be embodied in a carburetor engine for a vehicle. For example, in a well-known carburetor engine as shown in FIG.
Based on the relationship 1, the ECIJ 13 may be configured to control the operation of the slow cut solenoid 14 for fuel adjustment.

In addition to this, the present invention can be implemented by changing a part of the structure as appropriate without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, according to the present invention, in the fuel supply control method for cutting fuel to an internal combustion engine based on the engine speed and the throttle valve opening, it is possible to cut fuel during deceleration operation. This can be done quickly and fuel consumption can be reduced, and fuel resupply can be performed more quickly when changing from deceleration to acceleration, further improving the responsiveness of acceleration. It exhibits an excellent effect.

[Brief explanation of the drawing]

1 to 3 are drawings showing an embodiment embodying the present invention, in which FIG. 1 is a two-dimensional map showing the relationship between engine speed and throttle valve opening, and FIG. 2 is a fuel FIG. 3 is a schematic configuration diagram of a fuel supply system to which the supply control method is applied, and is a flowchart explaining the control operation of the ECU. FIG. 4 is a schematic configuration diagram of a fuel supply system to which a fuel supply control method is applied showing another embodiment embodying the present invention, and FIG. 5 is a diagram showing the relationship between engine speed and throttle valve opening in a conventional example. It is an explanatory diagram explaining a relationship. In the figure, 1 is an engine as an internal combustion engine, A is a fuel supply area, B is a fuel cut area, C is a semi-fuel cut area, Ll
is the setting level, L2 is the return reference level, Ne is the engine rotation speed, and θT11 is the haslo sotol valve opening degree.

Claims (1)

[Scope of Claims] 1. A fuel supply control method for cutting fuel to an internal combustion engine based on the engine speed and the throttle valve opening, comprising: A supply region and a fuel cut region are determined in advance, and the fuel cut is performed when the relationship between the actual engine speed and the actual throttle valve opening changes from the fuel supply region to the fuel cut region. Predetermining a return reference level of the throttle valve opening within the cut region,
A fuel supply control method for an internal combustion engine, characterized in that the fuel cut is canceled when the actual throttle valve opening changes in the opening direction beyond the return reference level.