JPH0524342B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply control device for an internal combustion engine,
In particular, the present invention relates to a fuel supply control device for an internal combustion engine that corrects the fuel injection amount during acceleration of the internal combustion engine.

[Prior Art] Conventionally, the amount of fuel injection required during acceleration of an internal combustion engine is required to be greater than the amount of fuel injection during steady state.
In order to correct the difference between the required fuel injection amount and the fuel injection amount, a device is installed that determines that the throttle is in an acceleration state and increases the fuel injection amount according to the opening angle when the opening speed of the throttle opening is greater than a predetermined value. It has been proposed (for example, Japanese Unexamined Patent Publication No. 150045/1983).

[Problems to be Solved by the Invention] However, even if the opening speed is the same in the acceleration state, the required fuel injection amount will differ if the throttle opening is different. The required amount of fuel injection is smaller when accelerating from around the throttle valve fully open than when accelerating from around the fully closed throttle valve. Therefore, if the fuel injection amount is corrected to increase primarily depending on the opening speed during acceleration as in the above-mentioned device, the problem is that the fuel injection amount will not be appropriate depending on the acceleration state and the exhaust emissions will deteriorate. There is a point.

The present invention has been made in view of the above-mentioned problems, and its purpose is to appropriately increase the amount of fuel injection during acceleration in accordance with the throttle opening degree and opening speed, thereby reducing exhaust gas. An object of the present invention is to provide a device that can prevent deterioration of emissions.

[Means for Solving the Problems] As shown in FIG. 1, the present invention includes a throttle opening detection means M1 for detecting the throttle opening of a throttle valve that adjusts the amount of air taken into an internal combustion engine; an opening speed detection means M2 for detecting the opening speed of the opening degree; a storage means M3 for storing an additional fuel injection implementation area set according to the throttle opening degree and the opening speed; a calculation means for calculating the upper and lower limits of the throttle opening from the additive fuel injection implementation area based on the addition fuel injection implementation area; An internal combustion engine comprising: a determining means M5 for determining; and a fuel supplying means M6 for increasing the amount of fuel supplied in accordance with the opening speed when the determining means M5 determines that the opening speed is within the range. The main focus is on the fuel supply control system.

[Function] With the above configuration, the throttle opening detection means
M1 detects the throttle opening, and opening speed detection means M2 detects the opening speed of the throttle opening.
Further, the storage means M3 stores an additional fuel injection implementation range set according to the throttle opening degree and opening speed.

Then, the calculating means M4 calculates the upper and lower limits of the throttle opening from the addition fuel injection implementation range based on the detected opening speed, and the determining means M5 calculates the throttle opening at which the detected throttle opening is calculated. Determine whether the value is within the upper or lower limit values.

Further, when the fuel supply means M6 is determined to be within the range by the determination means M5, the fuel supply amount is increased in accordance with the opening speed.

[Example] Hereinafter, an example adapted to the present invention will be described based on the drawings.

FIG. 2 is a configuration diagram showing an electronic fuel injection control device for an internal combustion engine according to this embodiment. In the figure, 1
is a six-cylinder engine; 2 is an intake pipe pressure sensor that detects the internal pressure of the intake manifold 3; 4 is an electromagnetically actuated fuel injection valve provided near each cylinder intake port of the intake manifold 3 of the engine 1; Fuel whose pressure is adjusted to be constant is fed under pressure to the fuel injection valve 4 . 5 is an ignition coil forming a part of the engine ignition system, and 6 is a distributor that distributes ignition energy from the ignition coil 5 to spark plugs (not shown) provided in each cylinder. As is well known, the distributor 6 rotates once for every two revolutions of the engine crankshaft, and is provided with a rotation angle sensor 7 therein for detecting the engine rotation angle. 8 is a control device consisting of a microcomputer, which will be described later.

9 is a throttle valve of the engine 1, 10 is a throttle sensor that detects the throttle opening of the throttle valve 9, 11 is a cooling water temperature sensor that detects the warm-up state of the engine 1, and 12 is an intake air temperature that detects the intake air temperature. Sensor, 13 is exhaust manifold 14
It is an air-fuel ratio sensor installed in the exhaust gas that detects the air-fuel ratio from the oxygen concentration in exhaust gas, and when the air-fuel ratio is smaller than the stoichiometric air-fuel ratio, that is, rich, it is about 1 volt, and when it is larger than the stoichiometric air-fuel ratio, that is, lean. Outputs a voltage of about 0.1 volt.

The control device 8 is a control device that calculates the magnitude and timing of a control signal for engine control, and
The fuel injection amount is calculated based on the detection signals of the intake pipe pressure sensor 2, the rotation angle sensor 7, the throttle sensor 10, the cooling water temperature sensor 11, the intake air temperature sensor 12, and the air-fuel ratio sensor 13. Adjust the valve opening time.

Similarly, the optimum ignition timing is calculated based on each detection signal using, for example, a data map in the ROM which will be described later, and based on this, an ignition timing signal is sent to the ignition coil 5 to adjust the ignition timing.

FIG. 3 is a detailed block circuit diagram of the control device 8 of FIG. In the figure, 100 is a central processor unit that calculates the synchronous injection amount of the basic synchronous injection that is normally performed based on the intake pipe pressure and engine speed, and the additional fuel injection amount based on the throttle opening speed, etc. . Note that the above-mentioned synchronous injection corresponds to synchronous fuel supply, and the above-mentioned additive injection corresponds to additive fuel supply. 101 is an interrupt command unit, and 102 is a central processor unit 10.
A rotational speed counter unit 103 calculates the engine rotational speed by counting cycles of a predetermined rotational angle based on a clock signal of a predetermined frequency from 0. A digital input port 104 is an A/D conversion processing unit having a function of A/D converting the detection signals from the intake pipe pressure sensor 2 and the throttle sensor 10 and reading them into the central processor unit 100.

105 is the central processor unit 100
105A is a memory unit in which a control program is stored and output information from each unit 101, 102, 103, 104 is stored.
is a read-only memory (hereinafter referred to as ROM) 10 in which control programs and initial data are stored.
5B is a random access memory (hereinafter referred to as RAM) in which input data and data necessary for arithmetic control are temporarily read and written. 105C is a memory that is necessary for subsequent operation of the internal combustion engine even if a key switch (not shown) is turned off. Backup random access memory (backup random access memory) is nonvolatile memory that is backed up by a battery to hold data.
RAM).

Reference numeral 106 is a counter unit for controlling ignition timing including a register, which converts digital signals representing the timing to energize and cut off energization to the ignition coil 5 calculated by the central processor unit 100, that is, the ignition timing, into the engine rotation angle. Calculated as the period and time corresponding to (crank angle). A power amplifier 107 amplifies the output of the ignition timing control counter unit 106 to energize the ignition coil 5 and to control the timing at which the ignition coil 5 is de-energized, that is, the ignition timing.

108 is a fuel injection time control counter unit including a register, and is composed of two down counters having the same function. In this case, each down counter is connected to a central processor unit 100.
The digital signal representing the valve opening time of the fuel injection valve 4 calculated by , that is, the fuel injection amount, is converted into a pulse signal having a pulse time width giving the valve opening time of the fuel injection valve 4 . 109 is a power amplifier that amplifies the pulse signal from the counter unit 108 and supplies it to the fuel injection valve 4;
Two channels are provided corresponding to the configuration. 11
0 is each unit 101, 102, 103, 10
This is a common bus that transfers information between the terminals 4, 105, 106, and 108. Further, 41 to 46 are fuel injection valves that inject fuel into each cylinder.

As shown in FIG. 3, the rotation angle sensor 7 consists of three sensors 71, 72, and 73. That is, as shown in FIG. 4A, the first rotation angle sensor 71 detects the angle θ from the crank angle 0 only once every two rotations of the engine crankshaft, that is, every one rotation of the distributor 6. An angle signal A is generated at the position. As shown in FIG. 4B, the second rotation angle sensor 72 generates an angle signal B only once every two revolutions of the engine crankshaft at a position an angle θ before the crank angle of 360°. Third
As shown in FIG. 4C, the rotation angle sensor 73 of
For each revolution of the engine crankshaft, 6 angle signals C are generated at angle signal intervals equal to the number of engine cylinders, that is, in the case of 6 cylinders as in this embodiment, 6 angle signals C are generated at every crank angle of 0° to 60°. .

The interrupt command unit 101 is connected to each rotation angle sensor 7.
The angle signals, that is, the crankshaft rotation angle signals from 1, 72, and 73 are input, and a signal is sent to command the interruption of ignition timing calculation and the interruption of fuel injection calculation. As shown in FIG. 4D, the signal obtained by dividing the frequency of the angle signal C of the third rotation angle sensor 73 by two is transmitted to the first rotation angle sensor 7.
This interrupt command signal D is sent out as an interrupt command signal D immediately after the angle signal A of 1 is sent out.
The number of engine cylinders is delivered by rotation. Therefore,
In the case of a 6-cylinder engine, the signal is sent once every 120 degrees of crank angle to issue an interrupt command to the microprocessor unit 100 to calculate the ignition timing.

Further, the interrupt command unit 101 is configured as shown in FIG.
As shown in , the signal obtained by dividing the angle signal C of the third rotation angle sensor 73 by 6 is divided into the angle signal A of the first rotation angle sensor 71 and the angle signal B of the second rotation angle sensor 72. 360° (1 rotation) starting from the 6th point after the is sent out, that is, the crank angle of 300°
It is sent as an interrupt command signal E every time. This interrupt command signal E is sent to the central processor unit 1.
An interrupt command for calculating the fuel injection amount is given to 00.

Next, a flowchart of a control program for additive fuel injection executed by the control device 8 will be described. FIG. 5 shows the control program in the form of a subroutine. The process of this routine is repeated every 20 ms as one of the processes not shown.
First, when the process is started, in step 200, a signal from the throttle sensor 10 is taken in to calculate the throttle opening _{T Ai .} In step 201, the throttle opening obtained when this routine was last processed is read into the CPU 100 from the RAM 105B at a predetermined address as the throttle opening T _Ai-1 . In step 202, the throttle opening T _Ai calculated in step 200 is stored as T _Ai-1 in the RAM 105B at a predetermined address for the next processing. In step 203, throttle opening T _Ai and throttle opening T _Ai
Calculate the difference from _-1 and set the value as ΔT _A. Note that this routine is processed every 20ms, so
ΔT _A is the change in throttle opening for 20ms,
Corresponds to opening speed.

In step 204, the basic lower limit value of the additional fuel injection implementation range for ΔT _A is determined from the map stored in the ROM 105A and represented by the characteristics shown in FIG.
Find T _ALO and the basic upper limit T _AHO . Note that FIG. 6 is a graph showing the areas of the additional fuel injection implementation area and the additional fuel injection prohibited area, which are set based on the throttle opening degree and the opening speed of the throttle opening degree. The additional fuel injection implementation area is an area surrounded by two polygonal lines L1 and L2 that move apart as the opening speed increases. Areas other than this area are areas where additional fuel injection is prohibited.

Next, in steps 205 to 207, the basic lower limit value T _ALO and the basic upper limit value T _AHO are corrected according to the operating conditions of the internal combustion engine. That is, in step 205, the coolant temperature THW and the engine speed NE are respectively adjusted to the coolant temperature sensor 11. The correction coefficient is read based on the signal from the rotation angle sensor 7, and in step 206, a correction coefficient is determined according to the cooling water temperature THW and the engine speed NE from a predetermined map in the ROM 105A with the characteristics shown in FIGS. 7 and 8. Find K ₁ , K ₂ , K ₃ and K ₄ .

Here, K ₁ and K ₃ are correction coefficients of the basic lower limit value T _ALO ,
K ₂ and K ₄ are correction coefficients for the basic upper limit value, and from the figure, as the engine speed NE increases, the line L1
is lowered and the polygonal line L2 is raised to narrow the additional fuel injection implementation range. On the other hand, the polygonal line L1 is raised and the polygonal line L2 is lowered only when the cooling water temperature THW is low.
In other words, the characteristics of each correction coefficient are set so that the lower the cooling water temperature THW and engine speed NE are, the wider the additional fuel injection implementation range is, and the higher the engine speed NE is, the narrower the additional fuel injection implementation range. There is. This is to calculate an appropriate fuel injection amount according to the engine speed NE and cooling water temperature THW. Note that even if the additional fuel injection implementation area is newly modified by the correction coefficient, the area of the additional fuel injection implementation area will move away as the opening speed increases2.
It is still an area surrounded by the polygonal lines of the book. In step 207, the lower limit value T _ALO ,
The upper limit value T _AHO is corrected by correction coefficients K ₁ , K ₂ , K ₃ and K ₄ to obtain a new lower limit value T _AL and upper limit value T _AH .

Next, in step 208, the throttle opening T _Ai and lower limit value are determined.
Compare T _AL and throttle opening in step 209.
When T _Ai is compared with the upper limit value T _AH and T _AL ≦T _Ai ≦ T _AH holds true, the additional injection time T _ASY is calculated in step 210, and on the other hand, if T _Ai < T _AL and T _Ai > T _AH If it is established, this routine ends immediately. Note that the additional injection time T _ASY is determined as a linear function of ΔT _A. However, A and B are constants. In step 211, a signal based on the additional injection time T _ASY is output to the fuel injection valve 4, and this routine ends.

By performing this routine and performing the additive fuel injection in this manner, the additive fuel injection is additionally added to the synchronous injection, and fuel injection amount control is optimally performed. Note that the timing of addition can be set as appropriate.

As described in detail above, according to this embodiment, the two polygonal lines L1, which move apart as the opening speed increases,
The additional fuel injection implementation range is determined by L2, and by limiting the throttle opening for performing additional fuel injection with respect to the opening speed, additional fuel injection can be performed according to the opening speed and throttle opening. Moreover, the slopes of the above-mentioned polygonal lines L1 and L2 are expressed as parameters that indicate operating conditions, such as engine speed.
Since it is changed based on NE and cooling water temperature THW, the additional fuel injection amount can be controlled more precisely.

Therefore, while solving the fuel injection amount calculation delay and the fuel supply delay, the optimum air-fuel ratio is maintained in response to changes in the throttle opening degree and opening speed. Therefore, the exhaust emission can be improved. Furthermore, the acceleration performance of the vehicle can be improved.

Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to such an embodiment and can be implemented in various forms without departing from the gist of the present invention. For example, in the embodiment, the basic lower limit value T _ALO and the basic upper limit value T _AHO are corrected based on the cooling water temperature THW and the engine speed NE, but the engine condition such as the temperature of the engine body, the transmission position of the automatic transmission, etc. , the correction can be carried out using parameters representing the vehicle state such as vehicle speed.

[Effects of the Invention] Therefore, as described in detail, in the present invention, the additive fuel injection execution area is set according to the throttle opening degree and opening speed, and the addition fuel injection execution area is set depending on the throttle opening degree and opening speed. When the opening speed is within the range, the fuel supply amount is increased according to the opening speed. Therefore, since it is determined whether or not to increase the amount of fuel supplied according to the throttle opening degree and opening speed, the amount is increased, which is advantageous in that it is possible to prevent deterioration of exhaust emissions without impairing the acceleration performance of the vehicle. It has a positive effect.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a configuration diagram showing an electronic fuel injection control device for an internal combustion engine, and FIG.
Figure 4 is a block diagram of the control device, Figure 4 is a time chart of signals generated from the rotation angle sensor and signals output from the interrupt command unit, Figure 5 is a flowchart of the control program, and Figure 6 is the additive fuel injection. A graph of throttle opening speed versus throttle opening showing the execution range and additional fuel injection prohibition range, Figure 7 shows the cooling water temperature THW and correction coefficients K ₁ , K ₂
Graph showing the relationship between engine rotation speed and Figure 8
Graphs showing the relationship between NE and correction coefficients K ₃ and K ₄ are respectively shown. 4...Fuel injection valve, 7...Rotation angle sensor, 8...Control device, 10...Throttle sensor, 11...Cooling water temperature sensor, 105...Memory unit, 108...Counter unit.

Claims (1)

[Scope of Claims] 1. Throttle opening detection means for detecting the throttle opening of a throttle valve that adjusts the amount of air taken into the internal combustion engine; Opening speed detection means for detecting the opening speed of the throttle opening; a storage means for storing an additional fuel injection implementation range set according to the throttle opening degree and the opening speed; and a storage means for storing an additional fuel injection implementation range set according to the throttle opening degree and the opening speed; a calculating means for calculating the throttle opening; a determining means for determining whether the detected throttle opening is within the calculated upper and lower limits of the throttle opening; and a determining means for determining whether the detected throttle opening is within the range. A fuel supply control device for an internal combustion engine, comprising: a fuel supply means for increasing the amount of fuel supplied in accordance with the opening speed.