JPS58150043A - Electronically controlled fuel injection method of internal-combustion engine - Google Patents

Abstract

PURPOSE:To accurately correct fuel at applicable operation, by performing new correction with a residual value of a fuel correction quantity already under execution as the initial value when acceleration increase and deceleration decrease are duplicated in the method of suitably correcting the basic injection quantity in accordance with an engine operational condition. CONSTITUTION:In a digital control circuit 54, an injection 30 is controlled by reading the basic injection timing from an ROM by intake pipe pressure from an intake pipe pressure sensor 23 and engine speed from a crank angle sensor 44. Here at acceleration, a correction coefficient is increased, and then injection is decreased to a prescribed deceleration speed 0 at each engine speed to perform acceleration increase. While at deceleration, the correction coefficient is minimized, and then injection is restored to a prescribed restoration speed at each engine speed to perform deceleration decrease. When the acceleration increase and the deceleration decrease are duplicated, the deceleration decrease or acceleration increase is performed with a residual value of the acceleration increase or deceleration decrease already under execution as the initial value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled fuel injection method for an internal combustion engine.
In addition, the basic injection amount is determined according to the engine intake pipe pressure and engine rotation #, which is suitable for use in an automobile internal combustion engine 11 equipped with an electronically controlled fuel injection device of the intake pipe pressure type. The fuel injection amount is determined by correcting the basic injection amount according to the operating condition.5K
The present invention relates to JILK's revised electronically controlled fuel injection method for internal combustion engines.

One method of supplying a mixture with a predetermined air-fuel ratio to the combustion chamber of an internal combustion engine for automobile engines is to use an electronically controlled fuel injection device.This uses an injector to inject fuel into the engine. For example, the engine's intake manifold or throttle body may be
From 1111E or K, test the injector and control the valve opening time of the injector according to the engine operating condition 11.
The air-fuel mixture with a predetermined air-fuel ratio is supplied to the engine for combustion. These electronically controlled fuel injection devices can be roughly divided into so-called intake air amount type electronically controlled fuel injection devices, which calculate the basic injection amount according to the engine's mold air erosion and the engine speed. There is a so-called intake pipe pressure type electronically controlled fuel injection system that determines a basic injection amount according to intake pipe pressure and engine speed.

Of these, the former is the air fuel ratio? # It can be precisely controlled and is now widely used in automobile engines equipped with exhaust gas purification measures.

However, in this intake air volume type electronically controlled fuel injection system, the intake air volume changes by 50 times 8 degrees between idle and loaded, so the dynamic range is wide.
Not only does the accuracy when converting the amount of intake air into an electrical signal decrease, but when trying to improve the computational performance of the digital control circuit in the subsequent stage, the bit length of the electrical signal becomes long (which makes the digital control circuit expensive). It is necessary to use a suitable computer.

In addition, it is necessary to use a measuring device with a very precise structure, such as an air flow meter, to measure the amount of intake air.
One of the problems was that the equipment cost was high.

On the other hand, with the latter type of intake pipe pressure type electronically controlled fuel injection system, the change in intake pipe pressure is about 2 to 3 times smaller.
Since the dynamic range is narrow, the arithmetic processing in the subsequent digital control circuit is not only easy, but also the pressure sensor for detecting the intake pipe pressure is inexpensive. However, compared to electronically controlled fuel injection devices that use intake air flow, the control accuracy of the air-fuel ratio is lower, and the
During acceleration, the fuel injection amount cannot be increased unless the intake pipe pressure increases, so the air-fuel ratio becomes lean temporarily and the acceleration performance is low. In order to eliminate these drawbacks, conventional K
However, in order to improve drivability, the amount of increase must be extremely large, and in that case, the air-fuel ratio becomes overrich and the amount of carbon monoxide in the free gas becomes abnormal. Kt! However, it was not possible to maintain the air-fuel ratio within a predetermined range suitable for a three-way catalytic converter. This is because the fuel injection amount is feedback-controlled according to the output signal of the acid IR concentration sensor installed downstream of the exhaust gas 11.
Even in this case, the response of the oxygen 111 degree sensor is slow, so it is necessary to precisely control the intake pipe pressure type electronically controlled fuel injection device. However, it was thought that it would be difficult to use it in automobile engines that are equipped with exhaust gas purification measures.

In addition, in the intake pipe pressure type electronically controlled fuel injection device,
During deceleration, if the intake pipe pressure decreases, the air-fuel ratio can be maintained close to the stoichiometric air-fuel ratio by appropriately adjusting the increase or decrease, thus achieving both good adjustment performance and exhaust gas purification performance. An object of the present invention is to provide an electronically controlled fuel injection method for an internal combustion engine that can perform the following steps.

The present invention determines a basic injection amount according to the engine intake pipe pressure and engine rotation aK, and during transient periods, determines the fuel injection amount by correcting the basic injection amount according to the engine operating condition. In an electronically controlled fuel injection method for an internal combustion engine, an acceleration increase in which a correction coefficient is increased during acceleration and then attenuated, and a deceleration decrease in which the correction coefficient is decreased during deceleration and then recovered, and an acceleration increase and a deceleration decrease are performed. If there is a duplicate, the remaining value of the acceleration increase or deceleration decrease that is already being executed is used as the initial value, and the newly requested deceleration decrease or acceleration increase is executed. be.

An embodiment of the present invention will be described below with reference to a kindergarten.

A first embodiment of an intake pipe pressure type electronically controlled fuel injection device employing the electronically controlled fuel injection method for an internal combustion engine according to the present invention is as shown in FIGS. 1 and 2. An air cleaner 12 and an intake temperature sensor 1 for detecting the temperature of intake air taken in from the air cleaner 12
4, and 5, which is disposed in the intake passage 16 and opens and closes in conjunction with an accelerator pedal (not shown) disposed in the driver's seat. A throttle valve 18 for controlling the flow rate of intake air, and a potentiometer that generates a voltage output proportional to the idle contact and the opening degree of the throttle valve 18 for detecting whether the wrinkled throttle valve 18 is at the idle contact degree. a throttle sensor 20 including a surge tank 20, a surge tank 22, and a surge tank 2.
2, a bypass passage 24 that bypasses the throttle valve 18, and an opening area of the bypass passage 24 disposed in the middle of the bypass passage 24. Idle rotation control valve 2 for controlling idle rotation speed by controlling K
6 and the engine]O arranged in the intake manifold 28
an injector 30 for injecting fuel toward the intake port of the exhaust manifold 32, an oxygen concentration sensor 34 disposed in the exhaust manifold 32 for detecting the air-fuel ratio from the residual oxygen concentration in the exhaust gas, and the exhaust T-nifold a three-way catalytic converter 38 disposed midway in the exhaust pipe 86 on the downstream side of the engine 10; a distributor 40 having a distributor shaft that rotates in conjunction with the rotation of the crankshaft of the engine 10;
The distributor 40KFi3M includes a top dead center sensor 42 and a crank angle sensor that output a top dead center signal and a crank angle signal according to the rotation of the distributor shaft. 44, a cooling water temperature center t46 disposed in the engine block for detecting the engine cooling water temperature, a vehicle speed sensor 50 for detecting the running speed of the vehicle from the rotation speed of the output shaft of the transmission 48, and the aforementioned In accordance with the intake pipe pressure output from the intake pipe pressure sensor 23 and the engine rotation speed determined from the output of the crank angle sensor 44, the basic injection amount per engine is determined from the map, and this is calculated as a percentage of the throttle sensor 20. Output, the oxygen S degree sensor 3
4 output, the engine cooling water temperature output from the cooling water temperature sensor 46, etc., determines the fuel injection amount, outputs a valve opening time signal to the injector 30, and The ignition timing is determined according to the operating condition MK, and an ignition signal is output to the igniter-equipped coil 52.
Automotive engine 1 equipped with a digital control (b) path 54 that controls the idle-shift control valve 26 during idle.
In the intake pipe pressure type electronically controlled fuel injection system of No. 0, in the digital control W circuit 54, the throttle dragon f-2
0, the correction coefficient is increased when the idle switch 20 is turned off, and the after-idle amount is increased to attenuate at a predetermined attenuation speed. Depending on the speed, the correction coefficient is increased during acceleration, and then the throttle valve ei4FIL is increased to attenuate at a predetermined damping speed, and according to the increasing speed of the intake pipe pressure detected from the output of the intake pipe pressure sensor 23. , depending on the acceleration increase consisting of increasing the correction coefficient during acceleration and then decreasing the intake pipe pressure at a predetermined decay rate, and the decreasing rate of the throttle valve opening detected from the potentiometer output of the throttle sensor 20, The correction coefficient is reduced during deceleration, and then the throttle valve opening is reduced to recover at a predetermined recovery speed, and the correction is made during deceleration according to the decreasing speed of the intake pipe pressure detected from the output of the intake pipe pressure sensor 23. Decrease the coefficient and then perform a deceleration reduction consisting of an intake pipe pressure reduction that recovers at a predetermined recovery rate,
If the acceleration increase and deceleration decrease overlap, the remaining value of the acceleration increase or deceleration decrease that is already being executed is used as the initial value [and the newly requested deceleration decrease or acceleration increase is executed. .

The digital control circuit 54, as shown in FIG. Throttle sensor 2G potentiometer, intake pipe pressure sensor 2m.

Analog No. 1g inputted from the oxygen concentration sensor 34, cooling water temperature sensor 46, etc. is converted into a digital signal Kf and sequentially outputted to L.
: Digital signals inputted from the analog input port 2 with a multiplexer for input to the PU 60, the idle contact of the throttle sensor 20, the top dead center sensor 42, the crank angle sensor 44, the vehicle speed sensor 50, etc. at a predetermined timing. A digital input port 4 for importing into the CPL 160, and a read-only memory (hereinafter referred to as tOM) for storing programs or various harvest constants, etc.
66 and a random access memory (hereinafter referred to as FLA) for temporarily storing calculation data etc. in the CPLI 60.
A backup random access memory (hereinafter referred to as backup RAM) 70 that can be supplied with power from an auxiliary power source and retain memory even when Isoseki is stopped;
The calculation results in the CPL 160 are transmitted to the idle rotation control valve 26, the injector 30 . A digital output port door 2 for outputting to a coil 52 with an igniter, etc., and a common bus 7 that connects each of the above components.
It is composed of 4.

The action will be explained below.

First, the digital control circuit 54 uses the intake pipe pressure PM output from the intake pipe pressure sensor 23 and the engine rotation speed NE calculated from the output of the crank angle sensor 44 to calculate the basic injection time 1 from a map stored in advance in the ROM 66. 'P(
PM, NE).

Furthermore, the fuel injection time TAU is calculated by correcting the basic injection time TP (PM, NE) using the following equation according to the signals from each sensor.

TAU 雛TP (PM, NE) Tree (*F on 1+) ・,
(1) Here, F is a correction coefficient; when F is positive, it represents an increase correction, and when F is negative, it represents a decrease correction. Further, K is a tanu correction magnification for further correcting the corrected thread number F, and is normally set to 1.

A fuel injection signal corresponding to the fuel injection time TAU determined after 5K is output to the injector 30, and the injector 80 adjusts the fuel injection time in synchronization with the engine rotation.
I'A Ll is opened and fuel is injected into the intake manifold 28 (engine log).

In fact, in a suitable example, the acceleration increase and deceleration decrease are performed as follows.

That is, as shown in Fig. 3, when accelerating, the accelerator pedal is depressed, and the idle switch of the throttle t20 is activated as shown in Fig. 3 (AJ).

When the throttle valve is turned off at
Specifically, this LL increase is performed by, for example, first setting the correction coefficient F to a positive predetermined value,
Next, the damping is performed by K at a predetermined damping speed to 'ρ at every engine rotation or every fixed period of time.

Next, the throttle valve 18 is further opened, and the throttle valve opening degree TA detected from the potentiometer output of the throttle sensor 20 changes from time 1 to 1, as shown in FIG. 3(b)K. When the intake pipe pressure PM starts to rise at TA increase (hereinafter referred to as TA increase) is performed. Specifically, this TA increase is performed, for example, by setting a value (positive value) that is the sum of the values corresponding to the amount of change in the throttle valve opening at each predetermined time period as a correction coefficient F, and then calculating the correction coefficient F at each engine revolution or at a certain period of time. This is done by attenuating up to a at a predetermined attenuation rate.

Furthermore, when the intake pipe pressure PM begins to increase with a delay in increasing the throttle valve opening TA, from time t1, the accuracy increases according to the rate of increase in the intake pipe pressure PM, as shown by the solid line C in Fig. 3. Intake pipe pressure increase (hereinafter referred to as PM increase) is performed to perform a high increase correction. Specifically, this PM increase is performed, for example, by setting the correction coefficient F to 11 (positive value), which is the sum of values corresponding to the amount of change in intake pipe pressure every predetermined time, and then increasing , the damping is performed by a trap until a predetermined damping speed is reached.

In this case, K, time 1. ~1. Then, the LL increase and the TA increase overlap, and from time 11A is to t4, all increases overlap, and from time t4 to time t, the TA increase and PM increase overlap, but all increases overlap. If the amount increase correction is performed based on the %, the response will be too fast (but the accuracy will not be reduced due to the influence of the LL increase and the TA increase, which may result in an excessive increase. Therefore, in this example, as shown in FIG. 3) As shown by the thick solid line at 0, the acceleration increase is performed by following the maximum values of the LL increase, TA increase, and PM increase.

Next, during deceleration, when the throttle p18 begins to close at time t, the intake pipe pressure begins to decrease [, as shown in Figure 3 ρ!
As indicated by ID, throttle valve opening reduction (hereinafter referred to as TA reduction) is performed, which performs a rapid reduction correction according to the reduction speed of throttle valve opening [TA. Specifically, this TA, weight loss,
For example, a value (negative value) that is the sum of the values corresponding to the amount of change in the throttle valve opening station TA every predetermined time is set as the correction coefficient F, and then the correction coefficient F is set as the correction coefficient F, and then the correction coefficient F is set as the value (negative value) that is the sum of the values corresponding to the amount of change in the throttle valve opening station TA every predetermined time. This is done by restoring.

Next, when the intake pipe pressure PM starts to decrease, at time t, the intake pipe pressure PM decreases as shown by the solid line E in FIG.
Intake pipe pressure reduction (hereinafter referred to as PM reduction) is performed to perform highly accurate temperature reduction correction according to the rate of decrease in PM. This P
Specifically, for example, the M reduction is calculated by setting a value (negative value) that is the sum of values corresponding to the amount of change in the intake pipe pressure PM at each predetermined time as a correction coefficient F, and then calculating the value at each engine revolution or at a certain time. , by recovering up to θ at a predetermined recovery speed.

At this time, if TA weight loss and PM weight loss overlap, there is a risk that excessive weight loss will occur if both are performed together. Accordingly, in this embodiment, as shown in FIG. 3 (as shown by the uniformly thick solid line), by tracing the minimum values of the TA weight loss and PM weight loss, only the TA weight loss is performed at time t, ~1. t, ~t
, only PM reduction is performed.

Further, if the acceleration increase and the deceleration increase overlap, for example, as shown in FIG. 4(A)K, if the intake pipe pressure PM rapidly changes from a large tendency to a decrease tendency, Kf1. -1 until time tll when a request for execution of deceleration reduction occurs, Fig. 4 (B) K
Execute the PM increase using the PMtllll correction coefficient (hereinafter referred to as increase coefficient) FAK as shown at time t,...
After that, the residual value FA of the increase coefficient at the time t, K
II is the initial value, and p is determined by the PM reduction correction coefficient (hereinafter referred to as reduction coefficient) FB as shown in Fig. 4 (q).
Execute M reduction. Therefore, the final correction coefficient F is as shown in FIG. Note that Fig. 4 shows the case where there is a request to execute deceleration reduction while executing acceleration increase, but conversely, if there is a request to execute acceleration increase while deceleration reduction is being executed. , acceleration 111 m is executed using the remaining value of the reduction coefficient as the initial value.

Specifically, using a calculation program for the correction coefficient F as shown in FIG. 5, first, in step 101, changes in the intake pipe pressure PM, etc. Depending on gAK, it is determined whether or not it is the time of acceleration. If the determination result is positive, step 10
Proceed to step 2 to determine whether the current correction coefficient F is negative, that is,
Determine whether or not deceleration reduction is being executed. If the determination result is negative, the process proceeds to step 103, where the increase coefficient FA is calculated as described above using IQ as the initial value. If the determination result in step 1020 is positive, the process proceeds to step 104, where the value of register B, that is, the reduction coefficient FB
With the residual value of F as the initial value, the increase coefficient F is determined as described above.
AI calculation. After step 103 or step 104, the calculated value of the increase coefficient FA is stored in the register AK in step 105, and furthermore, in step 106, the contents of the register are set as the correction coefficient F, and this program is ended.

On the other hand, if the determination result in step 1010 is negative, the process proceeds to step 107, and it is determined whether or not deceleration is occurring, depending on the change state of the intake pipe pressure PM, etc. If the determination result is positive, the process proceeds to step 108, where it is determined whether the current correction coefficient F is positive, that is, whether acceleration fuel increase is being executed. If the determination result is negative, the process proceeds to step 109, where k is set as the initial value of Rina as described above.
and calculate the weight loss coefficient FB. If the determination result in step 108 is positive, the process proceeds to step 110K, where the value of the register A, filling, and the remaining value of the increase coefficient FA are used as initial values to calculate the decrease coefficient FB as described above. After steps 109 to 110 are completed, in step 111, the value of the calculated reduction coefficient #lFB is stored in register BK, and further, in step 112, the contents of register B are changed to correction coefficient F.
and exit this program.

Further, if the determination results in steps 101 and 107 are both negative, that is, at the time of acceleration.

If neither is the case during deceleration, the process proceeds to step 113, where it is determined whether the current correction coefficient F is positive, that is, whether acceleration is being increased. If the determination result is positive, the process proceeds to step 114, where the correction coefficient F is attenuated at a predetermined time or every predetermined number of rotations, and step 115
Then, store the information in register A after the decay and finish the process.

If the determination result in step 1130 is negative, the process proceeds to step 116, where it is determined whether the current correction coefficient F is negative, that is, whether or not deceleration and increase are being executed. If the determination result is positive, the process proceeds to step 117, where the correction coefficient F is recovered at a predetermined time or every predetermined number of rotations, and in step 118, the recovered correction coefficient F is stored in the register BK, and the correction coefficient F is stored in the register BK. Exit the program.

The above-mentioned 5KL is performed by combining extremely quick response LL increase, quick response TA increase/decrease, and highly accurate PM increase/decrease to perform acceleration increase and deceleration decrease. When the accelerator pedal is depressed, a large amount is increased, while when the accelerator pedal is gradually depressed, a small amount is increased, so that an appropriate increase or decrease can be achieved depending on how the accelerator pedal is depressed. Furthermore, even when acceleration/deceleration is continuous, it is possible to appropriately increase or decrease the air-fuel ratio, maintain the air-fuel ratio near the stoichiometric air-fuel ratio, and achieve both acceleration/deceleration performance and exhaust gas purification performance.

In the above embodiment, the KLLLL increase during acceleration, the A increase, and the PM increase are combined [acceleration increase is performed, KT during deceleration is
5K to perform deceleration weight loss by combining A weight loss and PM weight loss.
However, the combination of acceleration increase and deceleration decrease is not limited to this, and for example, it is also possible to omit the LL increase.

As explained above, according to the present invention, during acceleration, deceleration,
In addition, when acceleration/deceleration is continuous, appropriate increase/decrease correction can be performed, the air-fuel ratio can be maintained near the stoichiometric air-fuel ratio, and good acceleration/deceleration performance and exhaust gas purification performance can be achieved at the same time. Therefore, even when an intake pipe pressure type electronically controlled fuel injection device is used, there is an excellent effect that precise air-fuel ratio control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of an intake pipe pressure type electronically controlled fuel injection device for an automobile engine in which the method for controlling fuel injection for an internal combustion engine according to the present invention is adopted;
2vA is a block diagram showing the configuration of the digital control circuit used in the embodiment, FIG. 3 is a diagram showing the acceleration increase and deceleration decrease in the embodiment, and FIG.
Similarly, the figure is a line diagram showing the state of increase/decrease when acceleration increase and deceleration decrease overlap, and Fig. 5 is a flow chart showing the program for calculating the correction coefficient used in the above embodiment. be. 10... Engine, 14... Intake temperature sensor, 18.
... Throttle valve, 20... Throttle sensor, 23...
Intake pipe pressure sensor, 30... Injector, 34...
・Oxygen III! degree sensor, 40...Distributor, 42...Top dead center sensor, 44...Crack/rip angle sensor, 46...Cooling water temperature sensor, 54...Digital control circuit. Agent Takaya Ron (one person) Figure 3 tl Figure 44

Claims (1)

[Claims] (1) In addition to determining the basic injection amount according to the engine intake pipe pressure and engine speed, during transient times, calculate the engine operating condition! In an electronically controlled fuel injection method for an internal combustion engine in which the fuel injection amount is determined by correcting the basic injection amount according to lIK, the correction coefficient is increased during acceleration,
Next, an acceleration increase that is attenuated and a deceleration decrease that decreases the correction coefficient during deceleration and then recovers are performed, and if the acceleration increase and deceleration decrease overlap, the residual value of the acceleration increase or deceleration decrease that is already being executed is An electronically controlled fuel injection method for an internal combustion engine, characterized in that, as an initial value, a newly requested reduction in deceleration or increase in acceleration is executed.