JPS62165539A - Controlling fuel-injection quantity for internal combustion engine provided with automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the exhaust emission from becoming worse in the case where the quantity of fuel injection is caused to increase and decrease in accordance with the weighted mean value of the intake pipe pressure by increasing the quantity of fuel injection when an automatic transmission is shifted at the time of idling, while stopping the increase in quantity at the time of deceleration. CONSTITUTION:In an engine 20, the operation of its fuel injection valve 24 is controlled by means of an electronic control circuit 44. In the electronic control circuit 44, the present No.1, No.2 weighted mean values of the intake pipe pressure detected by a pressure sensor 6 are calculated from both the present intake pipe pressure and the past No.1, No.2 weighted mean values of the intake pipe pressure, which is obtained by weighting the weight of the No.1, No.2 weighted mean values obtained in the past. In addition, based on the differences between each of said mean values found by way of subtraction, the quantity of fuel injection is controlled so as to increase and decrease. In this case, when an automatic transmission is shifted to its driving range at the time of idling, the quantity of fuel injection is caused to increase in accordance with said differences, and at the time of running with a throttle valve 8 closed, said increase in quantity is caused to stop.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for controlling the amount of fuel injection for an internal combustion engine equipped with an automatic transmission, and in particular, a method for increasing the amount of fuel injection by automatic gear shifting of the automatic transmission during deceleration. The present invention relates to a fuel injection amount control method for an internal combustion engine equipped with an automatic transmission that prevents automatic transmission from occurring.

[Conventional technology] Conventionally, intake pipe pressure (absolute pressure) PM and engine speed N
A fuel injection amount control method is known in which a basic fuel injection amount is determined by E, and fuel is injected by correcting the basic fuel injection amount based on intake air temperature, engine cooling water temperature, etc.

In addition, in an internal combustion engine equipped with an automatic transmission, when idling, the shift lever moves from the non-drive range (N neutral) range or P (parking) range to the drive range D (drive) range or R (reverse) range, etc. When shifted from the non-driving range to the driving range, the fuel injection amount is increased by a predetermined 41 points to prevent the occurrence of engine stall, etc., since the load on the torque converter is applied.

In addition, during transient periods such as acceleration and deceleration, the intake pipe pressure changes and the amount of fuel adhering to the inner wall of the intake manifold changes, which changes the amount of fuel supplied to the engine combustion chamber and changes the air-fuel ratio. The fuel injection amount is increased or decreased by finding the average 6 (i) according to the formula.

... (1) However, PML is the detected current intake pipe pressure, PML
−, is the weighted average value of intake pipe pressure determined in the past;
PM is the current weighted average value of the intake pipe pressure, and K is a constant corresponding to the weight.

In the above equation (1), the constant IK is made small (for example,
4), the first weighted average value PM (a) is obtained, and when the constant K is increased (for example, 64), the second weighted average value PM (b) is obtained. Then, the increase/decrease coefficient of the fuel injection amount is determined based on the difference obtained by subtracting the second weighted average value PM(b) from the first weighted average value PM(a). If the fuel injection amount is controlled based on the product multiplied by becomes substantially constant, making it possible to prevent changes in the air-fuel ratio during transient times.

[Problems to be Solved by the Invention] However, in an internal combustion engine equipped with an automatic transmission, the engine speed changes as shown in Fig. 2 as the automatic transmission automatically changes gears during a transient period. However, as a result, the intake pipe pressure repeatedly increases and decreases as shown in Figure 2. Therefore, if the above method of increasing and decreasing the fuel injection amount using the weighted average value is applied to an internal combustion engine equipped with an automatic transmission, Since the above difference takes a positive or negative value as the intake pipe pressure changes during deceleration,
While the fuel injection amount is increased or decreased, exhaust emissions deteriorate and drivability deteriorates.
There is power. To solve this problem, it is possible to decelerate when the throttle valve is closed and stop increasing or decreasing the amount of fuel injection during deceleration, but automatic transmission shift changes are normally performed when the throttle valve is closed. Since the shift is performed from the non-driving range to the driving range, the fuel
A problem arises in that the I injection amount cannot be increased.

The present invention has been made to solve the above problems, and is an automatic transmission that can increase the amount of fuel injection iI) when shifting during idling of an automatic transmission, and also prevents +F from increasing the amount of fuel injection 13Y during deceleration. An object of the present invention is to provide a fuel injection amount control method for an internal combustion engine equipped with an internal combustion engine.

[Means for solving the problem] In order to achieve the above object, the present invention increases the weight of the first weighted average value obtained in the past of the intake pipe pressure, and calculates the intake pipe pressure in the past. The current first weighted average value is determined using the first weighted average value obtained in the past and the current intake pipe pressure, and the second weighted average value obtained in the past of the intake pipe pressure is A current second weighted average value is determined by using a previously determined second weighted average value of the intake pipe pressure, which is heavier than the first weighted average value, and the current intake pipe pressure. In a fuel injection amount control method for an internal combustion engine equipped with an automatic transmission, the fuel injection amount is increased or decreased based on the difference obtained by subtracting the current second weighted average value from the first weighted average value of When the automatic transmission is shifted from the non-drive range to the drive range while idling, the amount of fuel injection is increased based on the difference, and when the automatic transmission is shifted from the non-drive range to the drive range, and when the vehicle is running with the throttle valve closed, (Features characterized by stopping the increase in amount) The difference obtained by subtracting the second weighted average value PM (b) from the first weighted average value PM (a) becomes a positive value during acceleration. Therefore, if the fuel injection amount is controlled based on the difference between the two, the fuel injection amount will be increased during acceleration, and will be reduced to H1 during deceleration.Also, during idling, the fuel injection amount will be increased. When the automatic transmission is shifted from the non-drive range to the drive range, the fuel injection amount is increased based on the difference by increasing the difference by a predetermined amount, so that the engine output is not reduced. Furthermore, when decelerating with the 4-throttle valve closed, that is, when driving with the throttle valve closed, the increase in fuel injection amount based on the above difference is stopped and the intake pipe pressure fluctuates due to automatic gear shifting. It is determined whether the fuel injection amount is increased or not.

[Effects of the Invention] As explained above, according to the present invention, it is possible to increase the amount of fuel injection when shifting during fitting of an automatic transmission, and it is also possible to prevent the amount of fuel injection from being increased during deceleration. As a result, it is possible to obtain the effect of improving exhaust emissions and dry efficiency.

[Embodiment of the Invention] An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 3 shows a schematic diagram of an internal combustion engine to which the present invention is applicable.

This engine is equipped with a hydraulic automatic transmission and is controlled by an electronic control circuit such as a microcomputer, and a throttle valve 8 is disposed downstream of an air cleaner (not shown). Idle switch 1 that turns on when the throttle valve is fully open (idle position)
0 is attached, and a surge tank 12 is provided downstream of the throttle valve 8. In this surge tank 12.

A diaphragm type pressure sensor 6 is attached to detect the absolute pressure within the surge tank 12. This pressure sensor 6 has a built-in CR filter with a small time constant (for example, 3 to 5 m5ec) that can remove the minimum pressure pulsation component. Additionally, the surge tank 12 bypasses the throttle valve 8 and is located on the upstream side of the throttle valve and the downstream side of the throttle valve.
A bypass path 14 is provided to communicate with the.

This bypass path 14 has an ISO pulp 16 whose opening degree is adjusted by a pulse motor 16A equipped with a 4-pole stator.
B is installed. The surge tank 12 is communicated with the combustion chamber of the engine 20 via an intake manifold 18 and an intake boat 22. A fuel injection valve 24 is attached to each cylinder or cylinder group so as to protrude into the intake manifold 18.

The combustion chamber of the engine 20 is communicated via an exhaust boat 26 and an exhaust manifold 28 to a catalyst device (not shown) filled with a three-way catalyst. An 02 sensor 30 is attached to the exhaust manifold 28 to detect the residual oxygen concentration in the exhaust gas and output an air-fuel ratio signal. The engine block 32 has this block 32
A cooling water temperature sensor 34 is attached so as to penetrate through the water jacket and protrude into the water jacket. This cooling water temperature sensor 34 detects the engine cooling water temperature and outputs a water temperature signal.

A spark plug 38 is attached to each cylinder so as to penetrate the cylinder head 36 of the engine 20 and protrude into the combustion chamber. The spark plug 38 is connected via a distributor 40 and an igniter 42 to an electronic control circuit 44 composed of a microcomputer or the like.

A cylinder discrimination sensor 46 and a rotation angle sensor 48 are installed inside the distributor 40, each of which is composed of a signal rotor fixed to the distributor shaft and a pickup fixed to the distributor housing. In the case of a six-cylinder engine, the cylinder discrimination sensor 46 outputs a cylinder discrimination signal, for example, every 720° CA, and the rotation angle sensor 48 outputs an engine rotation speed signal, for example, every 30'CA.

The electronic control circuit 44 includes a neutral switch 52 that is attached to the automatic transmission 50 and turns on when the shift lever is in the N range or P range, and turns off when the shift lever is in a drive range such as the D or N range. A vehicle speed sensor 54 composed of a magnet and a magnetically sensitive element fixed to the speedometer cable is connected.

As shown in No. 41A, the electronic control circuit 44 includes a central processing unit (MPU) 60 and a read-only memory (R
OM) 62, random access memory (RAM)
)64. , <Tsukuupram (BU-RAM) 66, input/output capotro 8. Input port door 0° output port) 72,7
4.76 and a path 78 such as a data bus or control bus that connects them. The input/output capotro 8 includes an analog-digital (A/D) converter 78 . The pressure sensor 6 and the water temperature sensor 34 are connected via a multiplexer 80 and buffers 82,84. The O2 sensor 32 is connected to the input port door 0 via a comparator 88 and a buffer 86, and the cylinder discrimination sensor 46 and the rotation angle sensor 48 are also connected via a waveform shaping circuit 90. 52 and a vehicle speed sensor 54 are connected. The output port door 2 is connected to the igniter 42 via a drive circuit 92, the output port door 4 is connected to the fuel injection valve 24 via a drive circuit 94, and the output port door 6 is connected to the ISC pulp pulse motor via a drive circuit 96. Connected to 16A. In addition.

98 is a clock, and 100 is a timer. Above ROM6
2 stores in advance a control routine program, etc., which will be explained below.

Next, a routine of an embodiment in which the present invention is applied to a bipedal engine will be explained with reference to FIG. Note that an example in which a weighted average value is calculated by calculation will be described below. FIG. 1 shows a part of the main routine of this example, in which the current intake pipe pressure PML, which is A/D converted and recorded in the RAM in step 102, is calculated last time and is stored in the RAM. First weighted average value PM(
a) L-1 and the second weighted average value PM (b) L
In step 104 and step 106, the first weighted average value PM(a) is taken according to the following formula:
L and a second weighted average value PM (b),
The calculated first weighted average value PM (a) L,
The second weighted average value PM(b)+, is replaced with the previous first weighted average value PM(&) b-1, the previous second weighted average value PM(b)L+ memorize it in
...(2) ...(3) In the next step 108, it is determined based on the output of the neutral switch 52 whether or not the automatic transmission's shift lever is shifted to the N range. When it is determined that the current range is in the N range, the process proceeds to step 114, and when it is determined that the current range is not the N range, it is determined in step 110 whether or not the current range was determined to be the D range. When it was determined that the previous range was in the D range, the process proceeds to step 114, and when it was determined that the previous range was not in the D range, that is, when the shift was made from the non-drive range N range to the drive range D range, the process proceeds to step 112. 2 weighted average value PM(b)L
After reducing the value by a predetermined value α, the process proceeds to step 114.

In step 114, it is determined whether the idle switch 10 is on, and when the idle switch 10 is off, that is, when the throttle valve is open, in step 116, it is determined whether the idle switch 10 was previously on. do. If it is determined that the idle switch was off last time, the process proceeds to step 124, and if it is determined that the idle switch was last turned on, that is, when the throttle valve is opened from the closed state, the process proceeds to step 118. After reducing the weighted average value PM(b)L by a predetermined value α, the process proceeds to step 124.

On the other hand, when it is determined in step 114 that the idle switch 10 is on, it is determined in step 120 whether the vehicle speed SPD obtained based on the output of the vehicle speed sensor 54 is O. and.

When the vehicle speed SFD is not O, the value of the second weighted average value PM(b) is set to the value of the first weighted average value PM(a)L in step 122. The value and the second weighted average value are made equal.

In step 124, the first weighted average value PM(a)
The difference A is calculated by subtracting the second weighted average value PM(b)L from L.

In step 126, the difference A is multiplied by a constant B to obtain an increase/decrease coefficient FT.
Calculate C.

As a result of the above, when the shift lever of the automatic transmission is shifted from the non-driving range to the driving range and when the throttle valve is opened from the closed state, the difference A is increased by a predetermined value α, and the vehicle is driven with the throttle valve closed. , the difference A is set to O.

FIG. 5 shows an interrupt routine that is executed at every predetermined crank angle (for example, every 30° CA).
In Step 8, the current intake pipe pressure PML and engine speed NE are taken in, and in Step 130, the basic fuel injection amount T is taken in as in the conventional case.
Calculate P. Then, in step 132, fuel injection 11\TAU is calculated according to the following formula, and fuel injection is executed at a predetermined crank angle in a fuel injection routine (not shown).

TAU=TP・(1+FTC)・FAF...
(4) Note that F A j is an air-fuel ratio feedback correction coefficient for feedback-controlling the air-fuel ratio to the stoichiometric air-fuel ratio based on the 02 sensor output.

In the above equation (4), by setting the difference A to O as described above, the increase/decrease coefficient FTC is set to O, and fuel injection is executed to stop the increase/decrease in the fuel injection amount, and the difference A is increased by a predetermined value α. By doing so, the fuel injection amount is increased by increasing the increase/decrease coefficient FTC and executing fuel injection.

In addition, although the example in which the increase/decrease in the fuel injection amount is stopped by making the first weighted average value and the second weighted average value equal is explained above, the increase/decrease coefficient can be changed after calculating the increase/decrease coefficient. It may be set to 0 to stop the increase/decrease in the fuel injection amount, and the optimum value for each type of engine is adopted as the constant corresponding to one weight. Furthermore, in the above example, the first and second weighted average values are calculated by calculation, but it is also possible to calculate the first and second weighted average values by using two filters such as CR filters with different time constants. You may ask for it.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the main routine of an embodiment of the present invention, Fig. 2 is a diagram showing changes in intake pipe pressure during deceleration of an engine equipped with an automatic transmission, and Fig. 3 is a diagram to which the present invention is applied. FIG. 4 is a block diagram showing details of the control circuit of FIG. 3, and FIG. 5 is a flowchart showing the interrupt routine of the above embodiment. 6.φ.pressure sensor, 10 ports.idle switch, 24..fuel injection valve, 52.φφneutral switch, 54-..vehicle speed sensor.

Claims (1)

[Claims] (1) The weight of the first weighted average value of intake pipe pressure calculated in the past is increased, and the current intake pipe pressure is calculated by increasing the weight of the first weighted average value of intake pipe pressure calculated in the past and the current intake pipe pressure. the first of
At the same time, the weighted average value of the previously determined intake pipe pressure is determined by making the weight of the second weighted average value determined in the past of the intake pipe pressure heavier than the first weighted average value. Find the current second weighted average value using the weighted average value of 2 and the current intake pipe pressure, and calculate the difference by subtracting the current second weighted average value from the current first weighted average value. In the fuel injection amount control method for an internal combustion engine equipped with an automatic transmission that increases or decreases the fuel injection amount based on the difference, when the automatic transmission is shifted from a non-driving range to a driving range during idling, the fuel injection amount is increased or decreased based on the difference. A fuel injection amount control method for an internal combustion engine equipped with an automatic transmission, characterized in that the fuel injection amount is increased based on the difference, and the increase based on the difference is stopped when the vehicle is running with a throttle valve closed.