JPS5815735A - Control method of air-fuel ratio - Google Patents

Abstract

PURPOSE:To control air-fuel ratio in good accuracy at transient time and inactive time of an air-fuel sensor, by preforming integration processing control from output of the air-fuel sensor and storing a value in accordance with this integration information as non-volatile memory correction information at each condition of an engine in addition to said integration processing control. CONSTITUTION:A RAM107, fed with power from a battery 26 in no relation to a key switch 27, is connected to a CPU100 preforming arithmetic operation of a fuel injection quantity. The RAM107 is stored with cooling water temperature, from an analog input port 104, correction quantity, calculated on the basis of a digital value in accordance with intake air temperature, and a correction quantity k2, integration processing information as a function of the lapse of time by a timer 111. Then a corresponding map to various conditions of an engine is prepared from said correction quantity k2, and control can be performed in quick response to all operational conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device that detects the air-fuel ratio based on engine exhaust gas components and performs feedback control of the air-fuel ratio C2 of the air-fuel mixture supplied to the engine.

The conventional air-fuel ratio control means is a simple integral control based on the output C2 of the air-fuel ratio sensor.9 During the transient period of engine operation, the change in the basic air-fuel ratio or the correction speed of the integral control is performed. If p is too fast, the correction control cannot follow up, and if the air-fuel ratio sensor is inactive (2) air-fuel ratio feedback control cannot be performed, and sufficient air-fuel ratio control cannot be performed to ensure exhaust gas purification. I couldn't get him to do two lines.

Jin's invention has the above-mentioned points (; 94), so the output of the air-fuel ratio sensor (2) integral processing control 6 2 Kami, the value according to Jin's integral information for each state of the engine 6; non-volatile The air-fuel ratio is feedback-controlled using the correction information corresponding to the engine condition at that time and its integral information.

In this case, the conditions for storing the correction information in the nonvolatile memory 6 are as shown in (m) to (c) below.

Condition (a) An engine state in which the injection amount of the fuel injection valve or the injection pulse width applied to the injection valve is less than or equal to the set value or greater than the set value.

Condition (ms) Engine condition where the intake air amount of the engine is below the set value or above the set value.

Condition (e) The engine speed is below the set value or above the set value.

That is, the device according to the present invention is capable of controlling the engine during transient conditions;
Even when the air-fuel ratio sensor is inactive, the air-fuel ratio can be quickly controlled to the specified air-fuel ratio without any delay in response even when the engine is running low. It is an object of the present invention to provide an air-fuel ratio control device that can control the fuel ratio with high precision and does not cause deterioration of the exhaust gas dispersion.

19. This invention prevents the air-fuel ratio from being incorrect even when a vehicle is inspected (2) when the vehicle battery is removed, the contents of the non-volatile memory are erased, and a completely incorrect 9 value is written. It also aims to prevent people from being controlled.

An embodiment of the present invention will be described below with reference to Drawing 2. 1st
The figure shows the configuration of the engine section.The engine 11 is a well-known 4-Nicle spark ignition type engine mounted on a car. Air for frying is sequentially passed through the air cleaner 1j1 intake pipe IJ% gas liter valve 14. The inhaled fuel is supplied from a fuel system (not shown) to each cylinder C2 of the engine 11 through nine electromagnetic injection valves 11 m, 1 lb...
・The exhaust gas after combustion is supplied through exhaust manifold 1#, exhaust pipe 1r and three-way catalytic converter 1.
It will be emitted into the atmosphere after reaching 8 mag.

Intake pipe JJ (Secondly, engine 115: A potentiometer-type intake air amount center tJ jl that detects the intake amount of intake air and outputs an analog voltage corresponding to the intake air amount C.

and engine 11 (2) Detects the temperature of the intake air, and detects the intake air temperature 62 (analog detection signal)
A star-type intake air temperature sensor is installed that outputs .

A thermistor-type water temperature sensor 21 is installed in front of the engine IJ to detect the coolant temperature and output an analog voltage (analog detection signal) according to the coolant temperature. 2. The air-fuel ratio is detected from the oxygen concentration in the exhaust gas, and when the air-fuel ratio is smaller (rich) than the stoichiometric air-fuel ratio, C: about 1 volt (high level), and higher than the stoichiometric air-fuel ratio. An air-fuel ratio sensor IJ that outputs a voltage of about 11G2α1 volt (low level) is installed. The rotational speed of the clusterer shaft of the engine 11 is the rotational speed (
(number) Detected by the sensor 21 and outputs a frequency pulse signal according to the rotation speed. As this rotational speed (number) centzx, for example, the ignition coil of the ignition device may be used, and the ignition pulse signal from the primary terminal of the ignition coil may be used as the rotational speed signal.Detection of each of the above-mentioned sensors 919 to 2J The signals are supplied to the control circuit 244, which calculates the fuel injection amount based on each detection signal and controls the electromagnetic fuel injection valve 1.
1m, Jjk, etc. (2) to adjust the fuel injection amount.4.

FIG. 2 is for explaining the control circuit 24, so lee is a bimicroprocessor (OPU) that calculates the fuel injection amount, and 101 is the rotation number run I and the signal from the rotation speed senna III. The engine rotation number counter 101 interrupts the engine rotation speed in synchronization with the engine rotation speed. Upon receiving this signal, the interrupt control unit 101 sends an interrupt command signal to the interrupt control unit 101, which sends an interrupt command signal to the interrupt control unit 101.
11g 20%] Outputs the included signal.

102 is a digital input boat that transmits the signal of the air-fuel ratio sensor 22 and the digital signal of the starter signal from the starter switch 25 that turns on and off the operation of a starter (not shown) to the microphone stomach processor 10 (Ii'' knee). 1 #4 is an analog The analog input port consisting of the multi-prep control unit and the A-Dg converter converts each signal from the intake air flow rate cent) #, the absorption source sensor 20, and the cooling water temperature j1 and sequentially reads it! 105
is a power supply circuit that directly supplies power to Mior-2, which will be described later, from batch Shizuku 2C, and this battery 2g
The circuit (- indicates that the key switch 2r is provided, but the power supply circuit 101 does not pass through the key switch 11 (2 direct, /
(The battery 26 is connected to the key switch 21; the power is always applied regardless. The battery 2C is connected to the other power supply circuit 10 through the key switch 21.)
This power supply circuit 10g supplies power to parts 6 and 2 other than RAMJ Or, which will be described later. This RAMJIF is a temporary memory bit that is used as a temporary value while the program is operating.
- It constitutes a non-volatile memory in which power is always applied regardless of whether the engine is turned off or the stored contents are not lost even if the key switch j7 is turned off or the engine is stopped. A second correction amount ka, which will be described later, is also stored in the RλM10r. 108
10I is a read-only memory (ROM) that stores various constants during the program, and 10I is a counter for controlling fuel injection time including a register, which is composed of a down counter and is calculated by 100% microcontroller. A digital signal representing the valve opening time and fuel injection amount of the electromagnetic fuel injection valves Jim, llb, etc. is transmitted to the actual electromagnetic fuel injection valve 11.
A pulse signal 62 having a pulse time width that gives the valve opening time of m, jlb, . . . is converted into two. 110 is an electromagnetic fuel injection valve Ji
m, Jlb...

111 is a timer and measures the elapsed time! Ikuta p Setsuna 1004 2 transmission.

In other words, the rotation number counter 101 is connected to the rotation speed sensor 23.
The output (2) is, for example, the 0 interrupt that supplies an interrupt command signal to the engine once (the engine rotation speed is measured once and the interrupt control unit 102g is interrupted at the end of the measurement). The control section 101 generates the interrupt command 62 and the input side input signal, and the controller 1004 causes the processor 1004 to execute an interrupt processing routine for calculating the injection amount of the injection amount.

FIG. 3 shows a schematic diagram of the microprocessor 100, and this flow chart 6 explains the mechanism of the microprocessor 100 and also explains the operation of the entire configuration. That is, when the key switches 27 and 4 and the starter switches 2J are turned on to start the engine, a start command is issued from the first step 120, the main routine arithmetic processing is started, and the Stella 1
Initialization is executed in step 1216, and in step 122, the digital values corresponding to the cooling water temperature and intake air temperature (2) from the analog input port 104 are read. In step JJJ, the correction amount described later is calculated from the result. , this correction amount is stored in RmuMJ#F42.Step 1 Yamamoto 11
4, input the signal of the air-fuel ratio sensor j1 (from the digital input port), increase or decrease the correction amount (described later) by 1 as a fraction of the elapsed time according to tie q-111g=, and calculate this correction amount 1 (J, t〉integral). To store processing information in RAMJIF.

FIG. 4 shows a detailed 74-chart of the processing step Jj4 in which the correction amount as the integral processing information is increased or decreased by 2.

First, in Step 40-, it is determined whether the exchange heat ratio detector is in an active state or whether feedback control of the air-fuel ratio can be performed based on the cooling water temperature, etc. In this case, set 1 to 1-1 in step 4#-B Advance correction amount, and set Step 405 Advance to 9.
For pigeon lofts that can control return, proceed to step 40 J l:.

In step 401, it is determined whether the elapsed time has passed the unit time Atl or not, and if it has not passed, kl is not corrected and step 114 for this section is ended.

If time t1 has elapsed, step 401: If the air-fuel ratio is rich and the output of air-fuel ratio control 12 is a rich high level signal, step 40 J4
: Advances by S, decreases 2 obtained in the previous cycle by 1, and in step 401 (Advances 2, stores 2 as the new correction amount in M1111. In step 401, when the air-fuel ratio increases by 1, If there is a low level signal indicating the output of the air-fuel ratio sensor 22, step 404 (
Step 2, increase kJ by 2 to 4, and step 405 (
: Proceed, and increase or decrease the correction amount by 2 in this way. In step 111 of FIG. 3, the correction amount kJ is increased or decreased,
The result is stored in RAM 1671. Fig. S is a detailed chart of step 11J in which 3 is calculated and stored in this correction amount, and t) is memorized.

In step 4j-, the fuel injection valve 11m.

JJb... Injection amount or fuel injection 11
a, llb...(2) Determine whether the applied pulse width is within the set value, and if it is outside the set value, proceed to step 1711.
If it is within the set value, proceed to step 5oot2.
In step 800, it is determined whether the detected intake air amount sensor 1-(2) is within the set value, and if it is outside the set value, step 115 is terminated, and if it is within the set value, step JaJs2 is determined. Proceed to step 501 of Jin.

The nine engine revolutions detected from the revolution speed center t21 are:
Determine whether or not it is within the set value, and if it is other than the set value, end step 111, and if it is within the set value, proceed to step j02
Step 62 advances to determine the value of kl, and if it is 2-1, this processing step 118 is ended without any further steps. In addition,
The correction amount 1 forms a map like No. 6IIA by the intake air amount q and the engine rotational speed N.

The correction amount kJ on the map that corresponds to the intake air amount Q4 = Pengka@, engine speed N The engine rotation speed N (200t...m every 200t... proceeds to step 501, decreases km by 1 to Δ, and executes step try
The result is stored in ordinary person MlOF (2 in step s. If rkg>IJ- in step 602, the process proceeds to step 504, where 1 is increased by ΔkJ to the correction amount obtained in the previous cycle, and the process proceeds to step soa. Step 111 is completed. When step 125 in the main routine is completed, the process advances to step 122 (4).

Note that the initialization process in step 121 also executes the following. In other words, when the vehicle is being repaired during vehicle inspection (= the battery may be removed. The nine correction amount kJ stored in this rounded frame Mler may be destroyed and become a meaningless value C. Therefore, whether the battery has been removed or not. In order to detect (2) Put a constant of 9 predetermined patterns into a specific address of Birdman Mior, and when the program starts,
Determine whether the value of this constant is 4ζ and t) whether it is a false 9 value, and if it is 900 million, assume that the battery is defective, and change all values of the wAi amount hz to ``1''.
” C Initialize and reset the constants of the above-mentioned nine patterns 6 At the next startup 6 2 pattern yji! Yesha quizzes with unbroken numbers and 9 kJ will not be held.

Normally, the processing of the main routine y in steps 111 to 121 is executed repeatedly in the control program (= Therefore, in FIG. When the input is received, the microlog 47Tuna 100 is in the middle of processing the main routine, and immediately interrupts the processing and moves to the interrupt processing routine in step 110. In step 111, the engine rotation speed Ntl from the rotation speed counter 101! Take in the wash signal, then next C
Step l1lG: Take in the signal representing the intake air amount (intake amount) Q from the analog input port 1#4, and then -
In the second step 111, the rotation speed N and the intake air amount Q are stored in the zero-order C step 134 to be used as rounding parameters for the storage process of the correction amount kJ. Then, calculate the injection time width t). The calculation formula is ``In t-F, various correction amounts for fuel injection obtained in the main routine are read from RAMl0F, and correction calculations are made for the injection amount (injection time width) that determines the air-fuel ratio.Formula for calculating the injection time width T. is rT-txkxk11X
k8J, 0th order 6th step 1361; "C correction. Load the calculated fuel injection amount data into the counter 101C-. Proceed to 0th order step 111. Main routine 1: Return. When returning to the main routine only two times. The process returns to step 62 when the process was interrupted due to the interrupt process.

MicroProcera? The general functions of 100 are the same as above.

Considering the above, a large number of second correction amounts kJ (-, 7) are prepared according to the intake air amount and engine speed, so depending on the engine operating condition, the appropriate correction amount corresponding to the engine speed can be immediately calculated. C2 can be used. Fast-response control is possible under all operating conditions, including transient conditions. 8 etc.
2. The second correction amount kJ is corrected in accordance with the operating condition.

Automatically corrects deterioration C2 during engine and Senna changes over time. For.

In addition, in the case of the above embodiment 62, if the engine is continued to be operated under constant conditions, the correction amount will be 1 (the same B idiot) in the whole, and y fn + 14p for %'1ml'2
kIn: i, etc. (Second: C knee + with large difference from nearby values
Since there are cases where 1 is over 9, it is possible to simultaneously learn and correct the eyelet of kτ by 6 units. In this case, the correction amount of the main routine of the above embodiment is 1 arithmetic processing step J J
j l=, when 1 is "k J)IJ" in the correction amount as the integral processing information, the step 504 in the Sa(2)
is kffl ■ k" + 3 Δ, Kei F l ?: Kei i + 2 in k Yuki Kei to = Kei I + ha, k': Kei to: 'Kei 1 + ha So to': Kei to': Kei 1 + ha The program is programmed to perform the process of blurring. Stona]C
For 2, the area is set to be modified by ``1''. When rkj (IJ), step post 2 is performed, C2 is performed as above, and subtraction processing is performed, and RAMJOF (: is stored, respectively.

In the above-mentioned Example 62, the arithmetic processing in Fig. 5 to 3 is simplified as shown in Figs. 7 and 8[1, 9]. Identical steps are given the same reference numerals and their explanations will be omitted.

In addition, in the above embodiment (2), the correction amount "ks-to-kidney" is R
AMJ 07 contains # (= written nine value 6: correction amount is 2)
A predetermined correction amount hJ (or 3Hl,
2 Δkm, H I) was calculated by adding and subtracting 62), but this kl can be calculated by multiplying the correction amount kl (2 constant α, or the α base that decreases depending on the engine condition C2). It is also safe.

In the above embodiment C2, the correction amount kJ is stored in the RAM 101.
Using the intake air amount and engine rotational speed as rounding parameters that are divided and stored into In case of 4, the number of k. , k”.

k3...kIll may also be used.

Furthermore, in each of the above embodiments, the intake air amount was used as a rounded engine parameter to divide the correction amount kJ into 8AM101g and store it, but it is also possible to use the intake negative pressure throttle valve opening for example. Of course Ami.

In the above-mentioned embodiment 6, in step 5, 1 is calculated for the correction amount and stored. However, it is of course possible to rewrite the calculation of unit rotation of the engine -N@[1:kJ), and in this case, the unit rotation ΔN is 30W when the engine is steady.
Approximately 20 rotations during transitions such as U-turns and acceleration/deceleration is good in terms of control response and control accuracy.

As described above, the present invention is a method that includes an air-fuel ratio sensor that detects the air-fuel ratio of engine exhaust gas components, and controls the air-fuel ratio based on the signal 62 of this air-fuel ratio sensor. The output signal of the air-fuel ratio sensor is integrated with the output signal of the air-fuel ratio sensor. and a storage processing step of storing the engine state correction amount information in a non-volatile memory, and the storage processing step 6 stores the integral information obtained in the storage processing step 2 and the engine state correction information at that time among the nine engine state correction information stored in the non-volatile memory. It is characterized by B correction information corresponding to the state of The air-fuel ratio can be controlled accurately under all engine conditions, and the air-fuel ratio can be controlled accurately by compensating for changes in the engine over time, deterioration of the air-fuel ratio sensor, and even production variations. effective.

In this invention, in addition to the above requirement C2, it is determined whether the constant value written in advance at a specific address C of the non-volatile memory memory is an incorrect value at C2 when the engine is started, and Only when the memory value of each address in this non-volatile memory is changed to a predetermined value (- includes a processing step of rewriting it,
It has the excellent effect of preventing cases such as when the vehicle battery is removed during vehicle inspection or maintenance, the contents of the message disappear, and completely incorrect values are written, resulting in incorrect air-fuel ratio control. have

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of the control circuit shown in FIG.
Figure 2 is a schematic 70-chart of the miter n pulser, Figure 3 is a detailed flowchart of the step of obtaining 2 for the correction amount shown in Figure 3, and Figure 5 is a detailed flowchart of the step of obtaining 2 for the correction amount kj shown in Figure 3 A detailed flowchart of the steps to obtain, FIG. 6, is provided to explain the operation of this embodiment (one
7 to 9 are flowcharts each illustrating the operation of other embodiments of the present invention. 1 no. Arrival engine, 1 j... Air amount sensor, 22.
...Air-fuel ratio sensor, 23...Rotational speed sensor, 24.
...Control circuit, ioO... Microb four processor (OF
υ), xo'i...RAM (temporary memory storage that forms non-volatile memory). Applicant's agent Patent attorney Hikoichi Kagoe Figure 4 Figure 5

Claims (1)

[Claims] The engine is equipped with an air-fuel ratio sensor that detects the air-fuel ratio of the exhaust gas component C; A non-volatile memory 12 that can be read and written in accordance with the engine state includes a storage processing step for storing engine state correction information, and the integral information obtained in the key recording integral processing step and the engine state correction stored in the non-volatile memory are included. Among the information, the correction information corresponding to the engine state at that time and the control means according to C2 (2, engine 1 = injection amount ti of the fuel injection valve that forms the air-fuel mixture to be supplied are injector ≦ The set value of the injection pulse width (one set value for the applied injection pulse width) (one set value for the engine speed, the set value for the engine intake air amount) An air-fuel ratio control system characterized in that at least 41 of various engine states such as engine states made up of comparison information are set as specific driving conditions, and C2 is configured to perform calculation processing of a correction amount.