JP3559164B2 - Atmospheric pressure correction advance angle control method for internal combustion engine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an atmospheric pressure correction advance angle control method for an internal combustion engine for adjusting an ignition timing when an atmospheric pressure changes.
[0002]
[Prior art]
The ignition timing of the internal combustion engine is determined based on the intake air amount when the fuel supply amount is feedback-controlled. In general, since the atmospheric pressure is different between a flatland and a highland, the intake air amount is different even if the throttle valve is opened at the same throttle opening. In particular, when the throttle valve is fully opened, the difference in the amount of intake air between a flat ground and a highland appears remarkably. Therefore, since the optimum ignition timing shifts to the more advanced side at a high altitude, correction for advancing the ignition timing is required.
[0003]
For example, as disclosed in Japanese Patent Application Laid-Open No. 64-3265, there is known an apparatus in which an atmospheric pressure sensor for detecting the atmospheric pressure is provided and the ignition timing is corrected according to the detected atmospheric pressure. Similarly, in the case of detecting the intake pressure to perform the fuel supply control, the intake pressure sensor can be used to detect the atmospheric pressure, thereby detecting the difference in the intake air amount between the flat ground and the highland, and therefore, the highland. Is corrected to the advanced side.
[0004]
[Problems to be solved by the invention]
In the meantime, a so-called α-N system that determines a fuel supply control based on an opening degree of a throttle valve and an engine speed without detecting an intake pressure has been widely used in recent years. In this type, since the intake air amount is calculated based on the throttle opening, when the throttle opening is the same between a flat ground and a highland, the intake air amount actually differs due to a difference in the atmospheric pressure. Nevertheless, the difference cannot be detected. Therefore, when the fuel supply is feedback-controlled in a low or medium load operation state where the throttle opening is not fully opened, the change in the atmospheric pressure is estimated based on the change in the learned value of the feedback correction coefficient, and the Thus, the ignition timing is corrected and controlled.
[0005]
However, when the throttle valve is fully opened, the feedback control is not executed, so that the ignition timing cannot be corrected based on the learned value. For this reason, in order to correct the ignition timing when the throttle valve is fully opened, the correction amount is set in accordance with the atmospheric pressure of a flat ground where traveling frequency is high. That is, when the throttle valve is fully opened, the ignition timing is corrected by the set correction amount regardless of the traveling location.
[0006]
However, if the correction amount is set based on the atmospheric pressure on a flat ground, the atmospheric pressure is different from that on a flat ground when traveling on a highland, so that even if the ignition timing is corrected with the correction amount, the correction will not be sufficient. Therefore, the output of the engine may decrease more than the decrease in the atmospheric pressure, and the fuel efficiency and climbing performance may decrease.
In order to solve such problems,
An object of the present invention is to solve such a problem.
[0007]
[Means for Solving the Problems]
The present invention employs the following means in order to achieve such an object. That is, the atmospheric pressure correction advance control method for the internal combustion engine according to the present invention performs the power increase operation to stop the air-fuel ratio feedback control and the high load In this configuration, a correction amount of the ignition timing is set based on a learning value of the feedback correction coefficient of the learning zone corresponding to the operation region, and the ignition timing is corrected based on the correction amount.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is directed to a basic fuel injection amount determined based on a throttle valve opening and a rotation speed based on a learning value of a feedback correction amount set for a plurality of learning zones set according to an operating state of an internal combustion engine. In the atmospheric pressure correction advancement method of the internal combustion engine in which the feedback control is performed so that the air-fuel ratio of the internal combustion engine becomes the stoichiometric air-fuel ratio and the ignition timing is corrected by the learning value, the opening degree of the throttle valve is detected, When it is detected that the opening degree of the valve is substantially fully open, the power increase operation is performed to stop the feedback control of the air-fuel ratio , and based on the learning value of the learning zone corresponding to high rotation and high load operation. An atmospheric pressure correction advance control method for an internal combustion engine, wherein an advance amount is set and the ignition timing is advanced based on the set advance amount.
[0009]
With such a configuration, the ignition timing can be corrected during traveling on high altitudes where the atmospheric pressure is low, even when the feedback control is not being performed. Can be secured. Therefore, it is possible to prevent a reduction in fuel efficiency and climbing performance.
[0010]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
An engine 100 schematically shown in FIG. 1 is for an automobile that performs fuel supply (injection) control in an α-N system. A throttle valve 2 that opens and closes in response to an accelerator pedal (not shown) is provided in an intake system 1 thereof. And a surge tank 3 is provided downstream thereof. The throttle valve 2 is provided with a throttle sensor 21 for converting the rotational displacement of the rotary shaft 2a, that is, the opening of the throttle valve 2 (hereinafter referred to as the throttle opening) into an electrical signal. A power switch 22 is provided which is connected and mounted and operates near the fully open position of the throttle valve 2. The power switch 22 is for detecting a high-load high-rotation region, that is, an operation region where the power increase is required. As the throttle sensor 21, for example, a potentiometer can be typically used, and the throttle sensor 21 is configured to output an analog voltage d proportional to the throttle opening. The analog voltage d output from the throttle sensor 21 is input to the electronic control unit 6 and becomes a voltage proportional to the rotation angle, that is, proportional to the throttle opening. A fuel injection valve (injector) 5 is further provided near one end of the intake manifold 4 of the intake system 1 communicating with the surge tank 3, and the fuel injection valve 5 is controlled by an electronic control unit 6. I have to. In the exhaust system 7, an O ₂ sensor 8 for measuring the oxygen concentration in the exhaust gas is attached at a position upstream of a three-way catalyst 9 provided in a pipeline leading to a muffler (not shown). I have. The O ₂ sensor 8 outputs a voltage signal h corresponding to the oxygen concentration.
[0011]
The electronic control unit 6 is, for example, an engine for a three-cylinder automobile, and is constituted by a microcomputer system including a central processing unit (CPU) 6a, a storage unit 6b, and input and output interfaces 6c and 6d. I have.
A throttle sensor 21, an O2 sensor 8, a water temperature sensor 17, a water temperature sensor 17, a rotation angle sensor 14, a vehicle speed sensor 15, and a power switch 22 are connected to the input interface 6c. The water temperature sensor 17 outputs a water temperature signal e according to the cooling water temperature of the engine 100, and is preferably a thermistor, for example. The rotation angle sensor 14 outputs a rotation speed signal Ne for detecting an engine rotation speed NE, a cylinder discrimination signal G1 for detecting a crank angle, and a crank angle reference signal G2. It is preferable that the rotation angle sensor 14 is mechanically directly connected to a crankshaft (not shown) because it outputs a highly accurate signal. The vehicle speed sensor 15 outputs a vehicle speed signal c for detecting a vehicle speed.
[0012]
On the other hand, the output interface 6d is connected to the fuel injection valve 5 for each cylinder, an igniter 19 for outputting a cylinder-specific ignition signal, and the like. The igniter 19 performs a closing angle control, a constant current control, and the like based on a signal output from the electronic control device 6, and controls the ignition coil in which the spark plug SP is electrically connected to the secondary side in an ignition order. In addition, an ignition signal g for each cylinder is output.
[0013]
In the electronic control unit 6, a basic injection time TP is set using the throttle opening signal d output from the throttle sensor 21 and the rotation speed signal Ne output from the rotation angle sensor 14 as main information, and according to the engine condition. The basic injection time TP is corrected by various correction coefficients determined according to the above, the fuel injection valve opening time, that is, the final energization time T of the injector is determined. A program for injecting the fuel into the intake system 1 from the fuel injection valve 5 is stored. Moreover in this program, based on the output signal h output from the O ₂ sensor 8 calculates the feedback correction amount serving A / F feedback correction coefficient FAF at a predetermined cycle, at least the calculated A / F feedback correction coefficient FAF The fuel injection amount is determined by correcting the basic injection time TP, and the air-fuel ratio is learned and controlled.
[0014]
As the learning control of the air-fuel ratio, those known in the art can be widely applied. For example, the learning control of the A / F feedback correction coefficient FAF is calculated, and the learning value KG is calculated from the average value. May be. That is, when the deviation of the A / F feedback correction coefficient FAF from the control center is detected, the deviation disappears from the learning value KG stored in the learning zone AKG set according to the driving state. The learning value KG at that time is stored. The learning zone includes, for example, four zones, and includes a learning zone AKG1 including an idling operation state, a low-load learning zone AKG2, a medium-load learning zone AKG3, and a high-load learning zone AKG4.
[0015]
In addition to this, the program for the ignition timing control uses the power switch 22 to control the ignition timing when the feedback control is not being performed, that is, when the open control is being performed. When detected by the output signal, the advance amount of the ignition timing is set based on the learning value KG4 of the learning zone AKG4 corresponding to the high rotation and the high load operation, and the ignition timing is set based on the set advance amount. It is programmed to correct the lead angle. It should be noted that the ignition timing at the time of feedback control while traveling on flat ground or the like is determined based on the throttle opening, in other words, based on the intake air amount.
[0016]
The outline of the atmospheric pressure correction advance angle control program in the ignition timing control is as shown in FIG. Note that this program is repeatedly executed every predetermined time, for example, every 13.3 msec.
First, in step S1, it is determined whether or not the power switch 22 is on. This determination is made based on whether the power-on flag INFFLAG2'PSW 'indicating the state of the power switch 22 is set. In step S2, the atmospheric pressure correction advance angle APA_COMP of the ignition timing is set by the correction amount FAPACOMP (KG4) set based on the learning value KG4 of the learning zone AKG4 corresponding to the high-load high-speed operation region. In step S3, the ignition timing is determined by the following equation.
REAL_SA = REALSA + APA_COMP (1)
[0017]
In step S4, the atmospheric pressure correction advance angle APA_COMP is set to 0.
In such a configuration, the power switch 22 does not turn on when the throttle valve 2 is not opened to a substantially full open state when traveling on flat ground or highland, that is, when the air-fuel ratio is feedback-controlled, so that the power-on flag INFFLAG2'PSW ' Has been reset. Therefore, the control proceeds from step S1 to step S4 to step S3, and the atmospheric pressure correction advance angle APA_COMP is set to 0, so that the ignition timing REAL_SA is determined without correcting the value calculated based on the throttle opening.
[0018]
Next, when the throttle valve 2 is opened to a state of being substantially fully opened during uphill running on a highland or the like, the power switch 22 is turned on, and the air-fuel ratio is controlled to be open. It is determined by advancing the ignition timing REAL_SA by the atmospheric pressure correction advance angle APA_COMP. That is, at the time of the open control, the ignition timing REAL_SA is corrected by the atmospheric pressure correction advance angle APA_COMP based on the learning value KG4 that reflects the change in the intake air amount by the atmospheric pressure, so that the change in the atmospheric pressure is reflected.
[0019]
As described above, since the ignition timing REAL_SA is advanced based on the correction amount FAPACOMP (KG4) based on the learning value of the learning zone, the ignition timing REAL_SA approaches the ignition timing MTB immediately before reaching the flat shaft torque, and the engine 100 Can be minimized. In addition, since the ignition timing REAL_SA is optimized, it is possible to reliably prevent a reduction in fuel efficiency and hill-climbing performance.
[0020]
As described above, the learning value KG learns a deviation from the feedback control center due to a change in the atmospheric pressure when traveling at a high altitude, and reflects the change in the atmospheric pressure. It can be secured in the same way as when traveling on level ground. That is, when the atmospheric pressure changes after moving from a flat ground to a highland, the intake air amount changes accordingly. O ₂ output signal output from the sensor 8 varies according to a change in the intake air amount, A / F feedback correction coefficient FAF is set based on the output signal. The A / F feedback correction coefficient FAF reflects the change in the atmospheric pressure, and therefore, the learning value KG also reflects the change in the atmospheric pressure. Then, by correcting the basic injection time TP with the learning value KG, the basic injection time TP also reflects the change in the atmospheric pressure, and based on the correction amount FAPACOMP (KG4) set based on the learning value KG. Since the advance angle is corrected, the ignition timing reflects the change in the atmospheric pressure. As a result, even when traveling at high altitude, it is possible to set an optimal ignition timing according to a change in the atmospheric pressure at that time.
[0021]
Note that the present invention is not limited to the embodiment described above.
In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.
[0022]
【The invention's effect】
As described above, according to the present invention, the ignition timing can be corrected during traveling at high altitude where the atmospheric pressure is low, even when the feedback control is not being performed. Performance can be ensured. Therefore, it is possible to prevent a reduction in fuel efficiency and climbing performance.
[Brief description of the drawings]
FIG. 1 is a schematic structural explanatory view showing one embodiment of the present invention.
FIG. 2 is a flowchart showing a schematic control procedure of the embodiment.
[Explanation of symbols]
2. Throttle valve 6 Electronic control unit 6a Central processing unit 6b Storage unit 6c Input interface 6d Output interface

Claims (1)

The basic fuel injection amount determined based on the throttle valve opening and the rotational speed is corrected by a feedback correction amount learning value set for a plurality of learning zones set according to the operation state of the internal combustion engine. An atmospheric pressure correction advancement method for an internal combustion engine that performs feedback control so that the air-fuel ratio of the internal combustion engine becomes a stoichiometric air-fuel ratio and corrects an ignition timing by a learning value,
Detects the opening of the throttle valve,
When it is detected that the opening of the throttle valve is almost fully open, the power increase operation is performed to stop the feedback control of the air-fuel ratio. To set the advance amount,
An atmospheric pressure correction advance control method for an internal combustion engine, wherein the ignition timing is advanced according to a set advance amount.

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