JP3528192B2 - Method of returning from fuel cut of electronic fuel 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 method for recovering from a fuel cut of an electronic fuel control device mainly used for motorcycles.

[0002]

2. Description of the Related Art As a conventional fuel cut and a method for recovering from the fuel cut, as disclosed in Japanese Patent Laid-Open No. 58-27818, fuel is generated by the number of revolutions of an internal combustion engine (hereinafter referred to as an engine) and the throttle opening. There is a method of determining a cut area and returning from the fuel cut when exceeding the fuel cut area.

As another method, Japanese Patent Laid-Open No. 2-16
As disclosed in Japanese Patent No. 346, a fuel cut area is set from the engine speed and the throttle opening, and a fuel cut return area is set in advance in the fuel cut area. There is a method of recovering from fuel cut by looking at (differential value).

[0004]

However, the method for recovering from the fuel cut disclosed in Japanese Patent Laid-Open No. 58-27818 is a throttle until the throttle is closed and the fuel is cut and then the throttle is opened to recover from the fuel cut. There is a problem that the stroke is not constant and drivability deteriorates. Also, since the fuel cut line and the line that recovers from the fuel cut are set to the same setting line, if the fuel cut region is widened to make the fuel cut during deceleration as quickly as possible, the fuel supply region will be narrowed and accelerated operation At this time, a response delay occurs in the timing of fuel re-supply, and the acceleration operation becomes unstable. On the contrary, if the fuel supply area is widened in order to refuel the fuel as quickly as possible during acceleration operation, the fuel cut area becomes narrower, resulting in a delay in fuel cut response, which deteriorates fuel efficiency. Exhaust gas purification performance cannot be satisfied.

Also in the method disclosed in Japanese Patent Laid-Open No. 2-16346, the setting of the differential value indicating the amount of throttle change does not satisfy all throttle operating speeds, and the throttle stroke from fuel cut to recovery is not constant. It was

Therefore, the present invention stabilizes the throttle stroke from fuel cut to return to prevent deterioration of drivability due to fuel cut, and also prevents deterioration of fuel efficiency due to lowering of the fuel cut line, thereby ensuring sufficient exhaust gas emission. It is an object of the present invention to provide a method of returning from a fuel cut that satisfies the purification performance.

[0007]

A solution for the] Therefore, the present invention is inner
The opening of the throttle valve that controls the intake air amount to the combustion engine
When the value falls below the fuel cut line which is set in advance, and the fuel cut step for cutting the fuel injection into each cylinder of the internal combustion engine, the fuel cut step
The throttle opening is preset
After falls below have fuel cut line, said slot
The value of the opening is below the fuel cut line,
Also, while the value is decreasing, a return line setting step of sequentially updating a value obtained by adding a predetermined amount to the throttle opening value as a return line, and the return line setting
After the return line is set in step, said slot
A fuel injection returning step of returning the fuel injection to each of the cylinders when the value of the torque opening exceeds the return line.

Further, a refuel cut prohibiting step of prohibiting the fuel cut for a predetermined time after the fuel injection returning step may be provided.

Further, the fuel cut line may be determined by the internal combustion engine speed and the load parameter.

[0010]

According to the present invention, when the throttle opening value falls below the fuel cut line, the fuel injection to each cylinder is cut, and further, in the fuel cut step, the throttle
Fuel cut li
After this , the return line is a value obtained by adding a predetermined amount to the throttle opening value. When the value of the throttle opening decreases, the return line is updated by adding a predetermined amount to the value as the return line. When the value of the throttle opening exceeds the return line. , Returning fuel injection to each cylinder.

Further, after the fuel injection is restored, the fuel cut may be prohibited for a predetermined time.

Further, the fuel cut line may be determined by the engine speed and the load parameter.

[0013]

FIG. 1 is a system configuration diagram of an embodiment using the present invention. The system configuration diagram will be described below.

An intake pipe 2 is provided in an engine 1 as an internal combustion engine.
And the exhaust pipe 3 are respectively connected. Then, the air sucked through the air cleaner 4 is sucked into the engine 1 through the intake pipe 2, and the exhaust gas from the engine 1 is exhausted through the exhaust pipe 3 and the catalyst 5.

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

A throttle valve 10 is provided in the middle of the intake pipe 2. The throttle valve 10 has a throttle opening T
A throttle position sensor 11 for detecting A is connected. An intake pipe pressure sensor 12 for detecting a negative pressure of the intake pipe is connected to the surge tank 2a in the middle of the intake pipe 2.

An electronic control unit (ECU) 13 for controlling fuel supply has a built-in memory. The ECU 13 inputs detection signals from the water temperature sensor 9 and the intake pipe pressure sensor 12, and based on the detection signals, sends an injection signal to the injector 6 to perform basic fuel injection amount control at the time of engine start and normal running. Output.

Further, the ECU 13 is a distributor 8
The detection signal of the engine speed Ne detected at 1 and the detection signal of the throttle opening TA detected at the throttle position sensor 11 are input. Then, the ECU 13
Outputs a cut signal or an injection signal to the injector 6 in order to perform fuel cut at the time of decelerating operation of the engine 1 or to refuel when changing from the decelerating operation state to the acceleration operation based on these detection signals. To do.

That is, the memory of the ECU 13 has a structure shown in FIG.
A two-dimensional map as shown in is stored in advance as data. This map has a fuel cut line CL that is predetermined based on the relationship between the engine speed Ne and the throttle opening TA. The value of the fuel cut line CL is set to increase as the engine speed Ne increases. Then, a line that is HS higher than CL with reference to this fuel cut line CL is set as RL, and this is set as a fuel injection return line when fuel cut is not performed.

Based on the detection signals from the distributor 8 and the throttle position sensor 11, the ECU 13 determines that the relationship between the actual engine speed Ne and the actual throttle opening TA has shifted from the fuel supply region to the fuel cut region. At some times, a cut signal is output to the injector 6 to perform fuel cut as a deceleration operation.

Further, the ECU 13 determines that the actual throttle opening TA is a predetermined amount H from the minimum value of the throttle opening during cutting.
When it is determined that the opening direction is changed beyond the return line RL that is higher by S, it is determined that the deceleration operation state is changed to the acceleration operation and the injector 6 is used to cancel the fuel cut.
The injection signal is output to. That is, the throttle opening TA
The fuel cut is canceled and the fuel is re-supplied (return process) based on the change of the predetermined operation amount HS.

Next, an embodiment of the present invention will be described with reference to the flow chart shown in FIG. This flowchart is performed every 5 ms. Further, as an initial measure when the power is turned on to the ECU 13, XFC = 0, T
M = 200 is set. In addition, XFC represents a fuel cut execution flag, and TM represents a count value of the counter.

First, at step 101, the throttle opening TA is input. Next, in step 102, the engine speed Ne is input, and in step 103, the fuel cut line CL is read from the map stored in the memory of the ECU 13.

In step 104, if the fuel cut is performed when the engine speed is small, the drivability is affected. Therefore, the fuel cut is not performed below a certain engine speed. That is, it is determined whether the engine speed Ne is higher than a predetermined speed KN (2000 rpm in the present embodiment).
To 0. This counter is provided so that the fuel cut is not performed again immediately after returning from the fuel cut. Next, at step 116, the fuel cut execution flag is set to 0. Then, in step 118, the return line RL is calculated (reset). The return line RL is RL = CL when fuel is not cut.
Given by + HS. Here, HS is a constant and is 0.5 ° in this embodiment.

In step 104, the engine speed N
When e becomes larger than the predetermined value KN, the routine proceeds to step 105. In step 105, it is determined whether the fuel cut execution flag XFC is 1. If not 1, the process proceeds to step 112. In step 112, it is determined whether the counter TM is 0. If it is 0, the routine proceeds to step 113, where it is determined whether the throttle opening TA is smaller than the fuel cut line CL. If it is not smaller, the fuel cut is not executed, the routine proceeds to step 118, where the return line RL is reset and this routine is skipped. If it is smaller, it is determined that the fuel cut is to be executed, and the routine proceeds to step 114, where the fuel cut execution flag XFC is set to 1 and the routine proceeds to step 107.

Steps 107 to 109 are steps for calculating the return line RL from the relationship TA + HS and for holding the lowest value as the return line RL. At step 107, TA + HS is set as a temporary return line CT. In step 108, it is determined whether or not this temporary return line CT is smaller than the current return line RL, and when CT is smaller, this temporary return line CT is set as the return line RL in step 109. When CT is RL or more in step 108, step 10
Skip 9 and skip this routine.

In step 105, the fuel cut execution flag X
If FC is 1, the process proceeds to step 106. In step 106, it is determined whether the throttle opening TA is smaller than the return line RL. If it is smaller, it is assumed that the fuel cut is to be continued and the routine proceeds to step 107, where step 107
~ In step 109, the above-mentioned processing is performed. If it is not smaller, the routine proceeds to step 110, where the processing for returning from the fuel cut is started.

At step 110, the value of the counter TM is set to 2
Set to 00. Then, in step 111, the fuel cut execution flag XFC is set to 0. Then step 1
In step 18, the return line RL when the fuel cut is not performed is reset and this routine is skipped.

After returning from the fuel cut, step 105
Since the fuel cut execution flag XFC is 0 when the time comes, the routine proceeds to step 112. Then, in step 112, it is determined whether or not the counter TM is 0. However, since the counter TM is set to 200 in step 110 when returning from the fuel cut, the process proceeds to step 117. At step 117, the value of the counter TM is decremented by one. Then, step 118
Then, the value of the return line RL is reset and this routine is skipped. The value of the counter TM becomes 0,
The process is repeated from step 112 to step 113. By this process, after returning from fuel cut,
The fuel cut is not performed again immediately (200 (value of TM) after returning from the fuel cut in this embodiment)
× 5 ms (flowchart execution cycle) = 1 sec, fuel cut is not performed).

In this embodiment, step 11 in FIG.
3, step 114 is the fuel cut step, step 107, step 108, step 109 is the return line setting step, step 106, step 111 is the fuel injection return step, step 110, step 11
2, step 115, and step 117 correspond to the refueling cut inhibition step and function.

Next, description will be made with reference to the flow chart relating to fuel injection shown in FIG. This processing is performed by angle interruption for each rotation angle signal sent from the distributor 8 at regular intervals.

First, at step 201, it is judged if the fuel cut flag is 0. If it is 0, the fuel injection is performed as usual in the subsequent processing. If it is not 0, this routine is terminated and fuel cut is performed. The process of fuel injection after step 202 is publicly known.

In step 202, the engine speed Ne and the intake pipe pressure PM, which are basic operation parameters, are read, and in step 203 the basic injection time TAU is calculated. In step 204, the correction parameter is read. Water temperature THW, intake air temperature THA, and atmospheric pressure T are used as correction parameters.
A, throttle opening TA. And step 20
In step 5, the correction coefficient K1 is calculated from these parameters. In step 206, the power supply voltage + B is read. In step 207, the correction time K2 is calculated from this power supply voltage + B. Next, at step 208, the actual fuel injection amount TAU
Calculate INJ. This is TAUINJ = K1 × TA
Calculated from U + K2. This TA in step 209
Set UINJ to timer.

By performing the above processing, the fuel cut can be executed when the fuel cut execution flag XFC is 1. Next, a description will be given with reference to FIGS.

FIG. 2 is a diagram showing a fuel cut line set by the engine speed and the throttle opening stored in the ECU 13 and a return line when the fuel cut is not executed.

In this figure, the fuel cut region is set wider as the engine speed increases. Further, the fuel cut is set not to be performed below the predetermined engine speed KNe.

FIG. 5 is a timing chart when an operation like A in FIG. 2 is performed. The operation of the fuel cut execution permission flag XFC at that time is also shown. When the throttle opening TA falls below the fuel cut line at time T1, fuel cut is started. At this time, the fuel cut execution permission flag XFC is set to 1. After that, when TA becomes smaller, RL = T
The return line RL goes down while maintaining the relationship of A + HS. Even if the time becomes T2 and TA increases, the return line RL updates its value only when the throttle opening TA is decreasing, so the value is TAmin + HS.
It remains. At time T3, TA returns to the return line RL (TA
min + HS) exceeds the fuel cut flag XFC =
It becomes 0 and the fuel cut is stopped. After that, the return line RL is reset to the value of CL + HS.

In this embodiment, when returning from the fuel cut, the return line RL is reset to a value obtained by adding a predetermined amount to the fuel cut line CL, but this processing is not always necessary, and the return line RL is It may be set when the load parameter is below the fuel cut line.

In the present invention, the load parameter may be the intake pipe pressure PM in addition to the above embodiments. this is,
The throttle opening TA in FIG. 3 is changed to the intake pipe pressure PM, the fuel cut line is read from the map set according to the intake pipe pressure PM, and the HS value is set to 20 m.
It can be realized by setting mHg. Similarly, the load parameter may be the intake air amount GN. At this time, instead of the throttle opening TA in FIG.
N, the fuel cut line is read from the map set according to the intake air amount GN, and the value of HS is 0.03 g / rev. Can be realized by Further, the load parameters may be both the throttle opening TA and the intake pipe pressure PM, and the fuel cut may be set when at least one of the fuel cut execution flags is set. The fuel cut may be set only when the flag is set. Similarly, the throttle opening TA and the intake air amount G
You may implement in combination with N.

In addition, the fuel cut line may be set to a constant value irrespective of the engine speed, or a non-linear relationship may be established when the fuel cut line is related to the engine speed as in the embodiment. . The return line may be set only when the throttle opening is below the fuel cut line. In addition, by providing a fuel cut valve on the carburetor and controlling the fuel cut valve,
The present invention can also be applied to an internal combustion engine using a carburetor. Furthermore, the present invention can be applied not only to two-wheeled vehicles but also to four-wheeled vehicles and other 4-cycle and 2-cycle internal combustion engines that require drivability and exhaust gas purification performance.

[0041]

As described above, according to the present invention, the fuel can be quickly cut during deceleration and the recovery from the fuel cut can be performed with a constant throttle stroke. As a result, comfortable drivability can be obtained, and fuel consumption can be improved and sufficient exhaust gas purification performance can be maintained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment using the present invention.

FIG. 2 is a map stored in an ECU according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a process performed by an ECU according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a process of fuel injection of one embodiment using the present invention.

FIG. 5 is a time chart of an example using the present invention.

[Explanation of symbols]

1 engine 2 intake pipe 2a surge tank 6 injectors 8 distributors 10 Throttle valve 11 Throttle position sensor 12 Intake pipe pressure sensor 13 ECU

Claims (3)

(57) [Claims] 1. A slot for adjusting an intake air amount to an internal combustion engine.
In the fuel cut step for cutting the fuel injection to each cylinder of the internal combustion engine when the throttle opening representing the opening of the throttle valve is below a preset fuel cut line, and the fuel cut step. The throttle opening is
Go under the preset fuel cut line
After that, while the value of the throttle opening is below the fuel cut line, and while the value is decreasing,
A return line is set in the return line setting step of sequentially updating a value obtained by adding a predetermined amount to the value of the throttle opening as a return line, and the return line setting step.
And a fuel injection return step for returning the fuel injection to each cylinder when the value of the throttle opening exceeds the return line after the fuel cut of the electronic fuel control device. How to return. 2. The method of returning from the fuel cut of the electronic fuel injection device according to claim 1, further comprising a refuel cut prohibition step of prohibiting a fuel cut for a predetermined time after the fuel injection return step. 3. A method return from the fuel cut line is the engine speed and the throttle opening and the fuel cut of the electronic fuel control system according to claim 1 or claim 2, characterized in that it is determined by the .