JP3758539B2 - Control apparatus and control method for automobile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile control apparatus and control method, and more particularly to an automobile control apparatus and control method for efficiently controlling an engine power train in accordance with information such as a traveling environment.
[0002]
[Prior art]
Conventional control methods of this type, for example, as described in Japanese Patent Application Laid-Open No. Sho 62-126235, change in operating conditions, that is, engine load (intake pipe pressure, air-fuel ratio) in order to achieve both fuel economy and operability. The operation region is determined according to changes in the sensor signal and the like and the engine speed, and the target air-fuel ratio information set for each operation region is read to change the air-fuel ratio of the engine.
[0003]
[Problems to be solved by the invention]
When the target air-fuel ratio is changed using the engine load and the engine speed as parameters as in the prior art described above, the amount of fuel changes during acceleration, resulting in torque fluctuations and an uncomfortable feeling. Further, when the NOx reduction catalyst is not used, the torque fluctuation is also large because the air-fuel ratio changes significantly from the air-fuel ratio of 14.7 to the air-fuel ratio of 24 in order to reduce the NOx emission amount.
[0004]
An object of the present invention is to provide a control device and method that eliminates torque fluctuations when the air-fuel ratio changes, and makes it possible to improve both fuel economy and drivability.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an external environment detection means for detecting an external environment during driving of the automobile, and a traveling environment determination for estimating a current traveling environment, for example, a road gradient, a congested road, etc. according to the external environment. Means, data storage means for storing data for changing the driving characteristics according to the driving environment, switching means for switching the data according to the driving environment, and the control amount based on the data selected from the data storage means. It consists of a control amount calculating means for calculating and a control actuator for controlling a control object.
[0006]
According to the present invention configured as described above, since the data such as the air-fuel ratio is switched according to the traveling environment other than the steady traveling such as shifting, stopping, idling and shift lever operation, the driver is accompanied by the change of the air-fuel ratio. Discomfort due to torque fluctuation is eliminated. Therefore, it is possible to reduce practical fuel consumption and improve drivability.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0008]
FIG. 1 is a block diagram of an embodiment of the present invention. First, a signal or an image of the external environment detection means 1 for detecting the external environment situation during driving of the automobile is input to the traveling environment determination means 2. The traveling environment discriminating means 2 estimates the current traveling environment, for example, a road gradient, a congested road, etc. according to the external environment. Next, the data storage means 3 stores data for changing driving characteristics in accordance with the traveling environment. Then, the switching unit 4 selects data in the data storage unit 3 based on the environment determined by the traveling environment determination unit 2. The control amount calculation means 5 calculates a control amount based on the selected data and outputs it to the control actuator 6 to control the control target (engine, transmission, etc.).
[0009]
FIG. 2 is a specific example of the embodiment shown in FIG. As in FIG. 1, a signal or image of the external environment detection means 1 for detecting the external environment situation during vehicle driving is input to the driving environment determination means 2, and the current driving environment, for example, road gradient, traffic jam, etc., according to the external environment situation. Estimate roads. Next, the corrected air-fuel ratio storage means 7 stores corrected air-fuel ratios corresponding to a plurality of travel environments. The corrected air-fuel ratio data is switched by the switching means 4 to realize the air-fuel ratio of the engine corresponding to the traveling environment. Then, the values calculated by the corrected air-fuel ratio storage unit 7 and the basic fuel amount calculation unit 9 are input to the fuel amount calculation unit 8. The basic fuel amount is usually obtained from the air flow rate and the engine speed. The final calculation of the fuel amount is executed by obtaining a correction coefficient based on the data in the corrected air-fuel ratio storage means 7 and multiplying or adding to the basic fuel amount. This calculated value is output to the fuel injection valve 10 based on the engine rotation reference signal.
[0010]
FIG. 3 is a control block diagram in which an air flow rate control is added to the fuel control shown in FIG. The fuel injection valve control is the same as in FIG. In the air flow rate control, first, the driver intention grasping means 11 obtains a target drive shaft torque requested by the driver from signals such as the accelerator opening α and the vehicle speed Vsp. Thereafter, the engine torque calculation means 12 uses the target drive shaft torque, the transmission torque converter characteristics, the engine characteristics, and the like, and further obtains the target engine torque based on the data in the corrected air-fuel ratio storage means 7. Next, the throttle opening calculation means 13 calculates the target throttle opening based on the target engine torque, the engine speed, etc., and outputs it to the throttle control valve 14 that is electronically controlled by a motor or the like. That is, the addition of this air flow rate control can correct the engine torque that changes due to the change in the air-fuel ratio with the air flow rate, and can improve the drivability.
[0011]
FIG. 4 shows a specific example of air-fuel ratio switching. In the detection of the outside world situation, firstly, there is a method using an infrastructure such as information collection by a display board installed on a road or road information collection by FM multiplexing. Secondly, there is a technique in which an outside vehicle situation recognition sensor such as a TV camera is provided in the vehicle, and this processing data and a driving signal of the vehicle (for example, vehicle speed, output shaft torque, etc.) are used. For the detection of the outside world situation, an application method such as a combination of these two methods or an individual method is conceivable, and the usage differs depending on the detection accuracy and the application situation. Next, the driving environment includes uphill and downhill road gradients, traffic congestion, steady highway, acceleration, and urban areas where normal driving is performed. This environment is obtained by using the above-described external environment detection means. When the air-fuel ratio is switched, an air-fuel ratio that achieves both drivability and fuel economy is selected according to the driving environment. For example, in the uphill road gradient and highway acceleration, there is a high possibility of requesting the maximum output of the engine. Therefore, it is necessary to make the air-fuel ratio a rich mixture of about 13. Further, in the case of downhill road gradients, traffic jams, and steady driving on highways, high output is not required, so the air-fuel ratio is reduced to about 24 and the fuel consumption is greatly reduced. In the case of normal driving in an urban area or the like, the air-fuel ratio is set to a theoretical mixture of 14.7.
[0012]
Here, as shown in FIG. 5, the air-fuel ratio correction table is represented by the horizontal axis, the engine speed, the vertical axis, and the basic fuel injection width. In the low engine speed and low basic fuel injection width areas including idling, Use an air-fuel ratio that stabilizes combustion. For example, if the performance of the engine is improved, it is possible to operate with a thinner air-fuel mixture.
[0013]
FIG. 6 is a control flowchart when traveling on a congested road. First, in the process 15, the front inter-vehicle distance Sf, the rear inter-vehicle distance Sr, the vehicle speed Vsp, the basic fuel injection width Tp, and the engine speed Ne are read. In the process 16, the temporal change ΔSf of the front inter-vehicle distance is calculated by (Equation 1). In the process 17, the temporal change ΔSr of the rear inter-vehicle distance is calculated by (Equation 2). In the process 18, the acceleration G of the host vehicle is calculated by (Equation 3). In process 19, the average vehicle speed Vave of the host vehicle is calculated by (Equation 4).
[0014]
ΔSf = [Sf (n) −Sf (n−1)] / [T (n) −T (n−1)] (Formula 1)
ΔSr = [Sr (n) −Sr (n−1)] / [T (n) −T (n−1)] (Formula 2)
G = [Vsp (n) -Vsp (n-1)] / [T (n) -T (n-1)] (Formula 3)
Vave (n) = [Vsp (n) +... + Vsp (n−k)] / (k + 1) (Equation 4)
And in the process 20, the counter for memorize | storing the average vehicle speed Vave (na) before a times is performed. That is, it is determined whether or not x is a. If it is not a, 1 is added to x in process 21 and the process proceeds to process 24. If it becomes a, Vave (n) is substituted for the average vehicle speed Vave (na) a times before in processing 22, and x is set to 0 in processing 23. Next, in the process 24, it is determined whether or not the temporal change ΔSf of the front inter-vehicle distance calculated in (Equation 1) is, for example, 10 m / s or less. That is, when this temporal change ΔSf is large, it is considered that the vehicle ahead is abruptly started, and there is a high probability that no vehicle is present in front of the vehicle ahead. In the process 25, the time change with the rear vehicle is checked in the same manner as in the process 24, and it is determined whether or not the own vehicle is sandwiched between the preceding and following vehicles due to traffic congestion. In the process 26, the acceleration G of the own vehicle is compared. If the front is congested when starting, the start acceleration is limited. For example, if it is 0.5 g or less, it is determined that there is a high possibility of traffic. Finally, in the process 27, using the value obtained in the process 22, it is determined whether or not the average vehicle speed Vave (na) before a times is 5 km / h or less. If the average vehicle speed several seconds ago is 5 km / h or less, it is determined that the state of 5 km / h or less continues for a long time, that is, the possibility of traffic jam is high. Therefore, the judgments of the processing 24 to the processing 27 are comprehensively evaluated, and when all are satisfied, it is determined that there is a traffic jam and the processing proceeds to the processing 28. If any of the processing 24 to the processing 27 is No, the processing proceeds to the processing 29, and the corrected air-fuel ratio table of the traveling environment determined last time is used. In the process 28, since it is determined that there is a traffic jam, the A / F of the corrected air-fuel ratio table is set to 24 and a lean mixture. Then, in process 30, the corrected fuel injection coefficient k ₁ is calculated by the function h (A / F) of A / F in process 28. In process 31, a fuel injection width Ti determined by the basic fuel injection width Tp and the corrected fuel injection coefficient k _1, and outputs the processing 32.
[0015]
FIG. 7 shows a control flowchart of the air flow rate control. First, at step 33, the accelerator opening α, the vehicle speed Vsp, the engine speed Ne, the turbine speed Nt, the corrected air-fuel ratio A / F, and the speed ratio i are read. Next, in a process 34, the target drive shaft torque Ttar is obtained from the function f ₁ (α, Vsp) of the accelerator opening α and the vehicle speed Vsp. In the process 35, the function f ₂ (Ttar, Ne, Nt, i, c, λ) of the target drive shaft torque Ttar, the engine speed Ne, the turbine speed Nt, the transmission ratio i, the capacity coefficient c of the torque converter, and the torque ratio λ. ) To calculate the target engine torque Tet. Here, an inverse model of the torque converter is calculated. In the process 36, the target throttle opening degree θt is calculated from the function f ₃ (Tet, Ne, A / F) of the target engine torque Tet, the engine speed Ne, and the corrected air-fuel ratio A / F, and is output in the process 37.
[0016]
FIG. 8 shows a system configuration diagram of the present invention. An engine 39 and a transmission 40 are mounted on the vehicle body 38, and an air flow rate, a fuel amount, an ignition timing, a gear ratio, and the like are controlled by a signal from the engine power train control unit 41. For the fuel control, the mainstream intake port injection method, the in-cylinder injection method with good controllability, and the like are used. In addition, the vehicle body 38 is equipped with a television camera 42 for detecting the outside world situation and an antenna 43 for detecting infrastructure information. The image of the TV camera 42 is input to the traveling environment discrimination unit 44, and image processing is performed to recognize the front and rear inter-vehicle distances, traffic signal information, road signs, road conditions, and the like. Further, the antenna 43 is connected to the infrastructure information terminal 45, and traffic congestion information, traffic accident information and current position information due to the infrastructure are input from the infrastructure information terminal 45 to the traveling environment determination unit 44. And the map information memorize | stored in CD-ROM46 grade | etc., Is taken in into the driving environment discrimination | determination unit 44, and the present driving environment is discriminate | determined by the said infrastructure information and this map information. A signal corresponding to the driving environment is output from the driving environment determination unit 44 and input to the engine powertrain control unit 41. Based on this signal, the air flow rate, fuel amount, gear ratio, etc. corresponding to the driving environment are controlled. The engine power train control unit 41 is input with a throttle opening θ, a shifting signal FlgI, a vehicle speed Vsp, a shift lever switch signal Isw, and the like, and is used for control amount switching, traveling environment grasping, and the like.
[0017]
FIG. 9 is a control flowchart of air-fuel ratio switching control. In the present invention, it is necessary to change the air-fuel ratio according to the traveling environment. Therefore, if the air-fuel ratio change is executed in synchronism with the running state of the vehicle, for example, at the time of stopping, shifting, idling, etc., torque fluctuation due to the air-fuel ratio change can be prevented. First, in the process 50, the correction air-fuel ratio A / F, the throttle opening θ, the shift lever switch signal Isw, and the shifting flag signal FlgI are read. In process 51, it is determined whether or not the current corrected air-fuel ratio A / F (n) is equal to the previous corrected air-fuel ratio A / F (n-1). If equal, the routine proceeds to step 52, where the corrected fuel injection coefficient k ₁ is obtained by f ₄ [A / F (n−1)], and the previous air-fuel ratio is held. In the processing 53 A / F (n-1 ) = running A / F (n-1) , the process 54 outputs the corrected fuel injection coefficient k ₁ calculated in the process 52. If the current corrected air-fuel ratio A / F (n) is different from the previous corrected air-fuel ratio A / F (n-1) in process 51, the process proceeds to process 55 where the throttle opening θ is checked and idling is performed. Determine whether or not. For example, if it is 2 deg or less, it is determined as idling. In process 56, it is determined whether or not the shift lever switch Isw (n) has changed. That is, if the movement of the shift lever is checked, it is effective only when stopping or shifting, and is effective for changing the air-fuel ratio. In processing 57, it is determined whether or not the shifting flag signal FlgI is 1. In the case of 1, the air-fuel ratio can be changed in synchronization with the torque fluctuation at the time of shifting, and the torque fluctuation accompanying the air-fuel ratio change can be prevented. If any of the processing 55 to processing 57 is Yes, the processing proceeds to processing 58, and the corrected fuel injection coefficient k ₁ is obtained by f ₄ [A / F (n)] in synchronization with the change period, and a new target air-fuel ratio is obtained. Change to In the processing 59 A / F (n-1 ) = running A / F (n), the process 54 outputs the corrected fuel injection coefficient k ₁ calculated in the process 58.
[0018]
FIG. 10 is a control flowchart in the case where the traffic jam and the uphill / downhill overlap. For example, when there is a traffic jam on an uphill, an engine output corresponding to the uphill is required, and it is necessary to respond by varying the air-fuel ratio. First, in process 60, a traffic jam signal JAM and a road gradient β are read. In process 61, it is determined whether there is a traffic jam, that is, whether JAM is 1. In the case of 1, the process proceeds to process 62 and the traffic jam flag FlgJ = 1 is executed. In the case where it is not 1, the process proceeds to process 63 and the traffic jam flag FlgJ = 0 is executed. Next, in process 64, it is determined whether the road gradient β is, for example, 0.5% or more. If it is less than 0.5%, it is determined that the road is flat or downhill, and the air-fuel ratio may be about 24 of the lean air-fuel mixture. On the other hand, in the case of 0.5% or more, it is necessary to change the air-fuel ratio according to the gradient. Therefore, if it is 0.5% or more, the process proceeds to process 65, and the uphill flag Flgβ = 1 is executed. If it is less than 0.5%, the process proceeds to process 66, and the uphill flag Flgβ = 0 is executed. Then, in process 67, the AND of the traffic jam flag FlgJ and the uphill flag Flgβ is judged. If true, the process returns to process 68, and if false, the process returns. If true, the traffic jam and the uphill overlap, so the corrected air-fuel ratio A / F is obtained by processing 68 using the corrected gradient air-fuel ratio table and the function f ₅ (β) of the road gradient β shown in FIG. In process 69, the corrected fuel injection coefficient k ₁ is calculated using the corrected air-fuel ratio A / F obtained in process 68, and output in process 70.
[0019]
FIG. 11 shows a corrected air-fuel ratio with respect to the road gradient at the time of the traffic jam. In a traffic jam from the vicinity of a flat road to a minus gradient range, the engine output is not so necessary, and an air-fuel ratio of about 24 is sufficient. On the other hand, in the uphill slope, the required engine output increases according to the degree of the slope, so it is necessary to reduce the air-fuel ratio to make a rich air-fuel mixture.
[0020]
Practical fuel consumption can be improved by the above control.
[0021]
【The invention's effect】
According to the present invention, since the air-fuel ratio changes at any time according to the change in the driving environment, the engine output can be effectively used, and the practical fuel consumption is further improved. In addition, since the air-fuel ratio switching is always executed in accordance with a traveling environment other than steady traveling such as shifting, stopping, idling, and shift lever operation, the driver is free from discomfort due to torque fluctuations associated with air-fuel ratio changes. Therefore, fuel consumption can be reduced and drivability can be improved.
[Brief description of the drawings]
FIG. 1 is a control block diagram of an embodiment of the present invention.
FIG. 2 is a control block diagram showing a configuration of a specific example system according to the embodiment shown in FIG. 1;
FIG. 3 is a control block diagram in which air flow rate control is added to the fuel control shown in FIG. 2;
FIG. 4 is a conceptual diagram showing a specific example of air-fuel ratio switching.
FIG. 5 is an example of a target air-fuel ratio correction table.
FIG. 6 is a control flowchart when traveling on a congested road.
FIG. 7 is a control flowchart of air flow control.
FIG. 8 is a conceptual diagram showing the configuration of the system of the present invention.
FIG. 9 is a control flowchart of air-fuel ratio switching control.
FIG. 10 is a control flowchart when a traffic jam and an uphill / downhill overlap.
FIG. 11 is a correlation diagram showing the relationship of the corrected air-fuel ratio to the road gradient at the time of traffic jam.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Outside condition detection means, 2 ... Driving environment discrimination means, 3 ... Data storage means, 4 ... Switching means, 5 ... Control amount calculation means, 6 ... Control actuator, 7 ... Correction air-fuel ratio storage means, 8 ... Fuel amount calculation Means 9... Basic fuel amount calculation means 10... Fuel injection valve.

Claims (16)

An engine controlled by the ratio of air and fuel;
Outside world information detection means for detecting at least the distance between the front vehicle and the distance between the back vehicles and detecting the outside world situation when the vehicle is running,
Traveling environment determining means for determining a traffic jam situation based on information from the outside world information detecting means;
Control means for controlling the air-fuel ratio of the engine based on the determination result by the traveling environment determination means,
The traveling environment determining means is configured to calculate a temporal change in the inter-vehicle distance of the front vehicle and a temporal change in the inter-vehicle distance of the rear vehicle from the inter-vehicle distance from the external vehicle information detection means and the inter-vehicle distance of the rear vehicle. A vehicle control system that calculates and determines whether there is a traffic jam from a temporal change in the inter-vehicle distance of the preceding vehicle or the temporal change of the inter-vehicle distance of the rear vehicle, and a predetermined value. . In claim 1,
Take in the acceleration of the vehicle,
The travel environment determining means determines whether there is traffic congestion based on a temporal change in the inter-vehicle distance with the preceding vehicle, a temporal change in the inter-vehicle distance with the rear vehicle, the acceleration of the host vehicle, and a predetermined value held in advance. The vehicle control system characterized by distinguishing. In claim 1 or 2,
Capture the average vehicle speed of the vehicle for a predetermined time,
The travel environment determining means is configured to detect a traffic jam based on a temporal change in the inter-vehicle distance with the preceding vehicle, a temporal change in the inter-vehicle distance with the rear vehicle, the average vehicle speed of the host vehicle, and a predetermined value held in advance. An automobile control system characterized by determining presence or absence. In any one of Claims 1 thru | or 3,
Storage means for holding an air-fuel ratio value specified by the engine speed and the basic fuel injection width;
The vehicle control system, wherein the control means switches an air-fuel ratio of the engine held in the storage means based on a determination result by the traveling environment determination means. In claim 4,
The vehicle control system according to claim 1, wherein if the traveling environment determining unit determines that the traffic is jammed, the control unit controls the air-fuel ratio based on a value larger than a combustion stable air-fuel ratio. In claim 4,
The vehicle control system according to claim 1, wherein the control unit controls the air-fuel ratio based on a value greater than 14.7 if the travel environment determination unit determines that the traffic is jammed. In claim 4,
The control means calculates a fuel injection width from the switched air-fuel ratio and basic fuel injection width based on the determination result by the traveling environment determination means, and controls the engine according to the calculated fuel injection width. An automobile control system characterized by: In claim 7,
The vehicle control system characterized in that the control means calculates a corrected fuel injection coefficient so as to be the air-fuel ratio of the switched engine, and calculates a fuel injection width from the basic fuel injection width. A traveling environment determining means for determining a traffic jam situation based on at least information of the detected inter-vehicle distance with the preceding vehicle and the inter-vehicle distance of the rear vehicle;
Control means for controlling the air-fuel ratio of the engine based on the determination result by the traveling environment determination means,
The travel environment determining means calculates a temporal change in the inter-vehicle distance of the front vehicle and a temporal change in the inter-vehicle distance of the rear vehicle from the inter-vehicle distance from the front vehicle and the inter-vehicle distance of the rear vehicle. An automobile control device that determines whether or not there is a traffic jam from a temporal change in the inter-vehicle distance of the preceding vehicle or a temporal change of the inter-vehicle distance of the rear vehicle and a predetermined value. In claim 9,
Capture the acceleration of your vehicle,
The travel environment determining means is configured to determine whether there is a traffic jam based on a temporal change in an inter-vehicle distance with the preceding vehicle, an temporal change in an inter-vehicle distance with the rear vehicle, an acceleration of the host vehicle, and a predetermined value held in advance. The control apparatus of the motor vehicle characterized by distinguishing. In claim 9 or 10,
Take the average vehicle speed of your vehicle for a predetermined time,
The travel environment determining means is configured to detect a traffic jam based on a temporal change in the inter-vehicle distance with the preceding vehicle, a temporal change in the inter-vehicle distance with the rear vehicle, the average vehicle speed of the host vehicle, and a predetermined value that is held in advance. A control apparatus for an automobile characterized by determining presence or absence. In any one of Claims 9 thru | or 11,
Storage means for holding an air-fuel ratio value specified by the engine speed and the basic fuel injection width;
The control device for an automobile, wherein the control means switches the air-fuel ratio of the engine held in the storage means based on a determination result by the traveling environment determination means. In claim 12,
The vehicle control apparatus according to claim 1, wherein if the travel environment determination unit determines that the traffic is jammed, the control unit controls the air-fuel ratio based on a value larger than a combustion stable air-fuel ratio. In claim 12,
The vehicle control apparatus according to claim 1, wherein if the travel environment determination unit determines that the traffic is jammed, the control unit controls the air-fuel ratio based on a value greater than 14.7. In claim 12,
The control means calculates a fuel injection width from the switched air-fuel ratio and basic fuel injection width based on the determination result by the traveling environment determination means, and controls the engine according to the calculated fuel injection width. A control apparatus for an automobile. In claim 15,
The control device for an automobile, wherein the control means calculates a corrected fuel injection coefficient so as to be the air-fuel ratio of the switched engine, and calculates a fuel injection width from the basic fuel injection width.

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