CN109139894B - Automatic transmission gear-shifting control method based on front road information - Google Patents

Abstract

The invention provides a gear shifting control method of an automatic transmission based on front road information, which realizes gear control of the automatic transmission in an ascending preparation process, an ascending process, a slope top process, a descending preparation process, a descending process and a slope bottom process according to a slope angle of a plurality of points in a front set distance and a road sign of a plurality of points in the front set distance, the slope angle of a vehicle at the current running time and the road sign of the vehicle at the current running time, thereby realizing advanced gear-up before the ascending, avoiding frequent gear shifting in the ascending process, putting the automatic transmission in neutral gear in advance before the descending, maintaining the engine to have a certain braking force function in the descending process, putting the automatic transmission in an optimal gear, and improving the fuel economy and the dynamic property of the vehicle.

Description

Automatic transmission gear-shifting control method based on front road information

Technical Field

The invention belongs to the technical field of automobiles, relates to a gear shifting control method of an automatic transmission, and particularly relates to a gear shifting control method of an automatic transmission based on front road information.

Background

During running of the vehicle, the reasonable gear of the automatic transmission can enable the engine to work in a low oil consumption area as far as possible, fuel economy of the vehicle is improved, and the engine can work in a high power area, so that dynamic performance of the vehicle is improved. Therefore, the shift position of the automatic transmission is a key factor affecting the fuel economy and the drivability of the vehicle. Meanwhile, in the driving process of the vehicle, the front road information is constantly changed, and if the road information is considered, the gear of the automatic transmission is more reasonable. The electronic control unit of the automatic transmission can thus determine the target gear of the automatic transmission on the basis of the road information, the vehicle speed, and the driver's accelerator opening. When the current gear of the automatic transmission is not consistent with the target gear, the gear of the automatic transmission is changed from the current gear to the target gear, and the gear of the automatic transmission is controlled during the running of the vehicle, so that the fuel economy and the dynamic property of the vehicle are improved.

Disclosure of Invention

In order to solve the problem of frequent gear shifting in the process of ascending or descending in the conventional automatic transmission gear shifting control method, the invention provides an automatic transmission gear shifting control method based on front road information so as to improve the fuel economy and the dynamic property of a vehicle.

In order to solve the technical problems, the specific technical scheme of the method is as follows:

a gear-shifting control method of an automatic transmission based on front road information is characterized by comprising two stages, namely a first stage and a second stage, wherein the first stage and the second stage are in a sequential relation, namely the second stage is carried out after the first stage is completed, the first stage is the whole stage with a top of a slope in front, and the second stage is the whole stage with a bottom of the slope in front;

the control process of the first stage, namely the whole stage with the front slope top, is as follows:

step 1: judging that the vehicle enters a process of preparing for uphill driving, namely judging that the vehicle enters the process of preparing for uphill driving when a slope top mark appears for the first time in road marks at a plurality of points within a set distance in front of the current position; the road signs are divided into three kinds, namely non-top slope bottom signs, top signs and bottom signs;

step 2: acquiring a horizontal driving distance and a maximum uphill angle before uphill, wherein the horizontal driving distance and the maximum uphill angle before uphill are acquired through GPS information, and the maximum uphill angle is acquired through ramp angles of a plurality of points in a set distance in front, wherein the maximum uphill angle refers to the maximum ramp angle of a road in the process of finishing uphill driving;

and step 3: acquiring shift point offset, wherein the shift point offset is acquired through a mapping table 1, the horizontal distance of driving before an uphill is small, the larger the maximum uphill angle is, the larger the shift point offset is, and in the mapping table 1, the parameter of a first row is the horizontal distance of driving before the uphill, and the unit is as follows: rice, the parameters of the first row are the maximum uphill angle, unit: the other parameters are the horizontal distance of driving before an uphill slope and the shift point offset corresponding to the maximum uphill slope angle, and the detailed parameters in the mapping table 1 are finally obtained according to test calibration;

mapping table 1

	100	300	700	1200	1500	2000
							1	-5	-5	-5	-5	-5	-5
3	-5	-5	-5	-5	-5	-5
							5	-5	-5	-5	-5	-5	-5
7	-5	-5	-5	-5	-5	-5
							10	-5	-5	-5	-5	-5	-5
15	-5	-5	-5	-5	-5	-5

And 4, step 4: acquiring a basic shift point of the current gear of the automatic transmission, wherein the basic shift point of the current gear of the automatic transmission is acquired through a mapping table 2; that is to say, according to the current gear and the accelerator opening of the automatic transmission in the mapping table 2, the basic shift point of the corresponding current gear of the automatic transmission is searched, in the mapping table 2, the parameter of the first row is the current gear of the automatic transmission, the parameter of the first column is the accelerator opening value, and the other parameters are the accelerator opening value and the basic shift point of each gear corresponding to the current gear of the automatic transmission, the unit: at kilometer/hour, the detailed parameters in the mapping table 2 are finally obtained according to test calibration;

mapping table 2

	1	2	3	4	5	6
							10	20	30	40	50	60	70
30	20	30	40	50	60	70
							50	20	30	40	50	60	70
70	20	30	40	50	60	70
							90	20	30	40	50	60	70
100	20	30	40	50	60	70

And 5: acquiring a target shift point, wherein the target shift point is equal to the sum of the basic shift point of the current gear calculated in the step 4 and the shift point offset calculated in the step 3; in the process of preparing the vehicle to run uphill, whether the automatic transmission needs to be shifted up or down is judged by comparing the current vehicle running speed with the target gear shifting point, namely, if the current running speed is greater than the target gear shifting point, the automatic transmission is shifted up; if the current running speed is less than the target gear shifting point, the automatic transmission performs downshifting;

step 6: judging that the vehicle enters an uphill driving process, namely judging that the vehicle enters the uphill driving process when the current ramp angle is larger than a first uphill angle set value for the first time, wherein the time is the time of entering the uphill driving for the first time; the current time ramp angle is the actual road ramp angle of the position of the vehicle at the current time acquired by the GPS; the first uphill angle set value is 5, which is used for judging that the vehicle enters the uphill driving process.

And 7: acquiring a gear at the first uphill driving moment, namely a basic uphill gear;

and 8: acquiring an uphill gear correction value of the automatic transmission, wherein the uphill gear correction value of the automatic transmission is acquired through a mapping table 3, and in the mapping table 3, a parameter of a first row is a vehicle running speed value, and a unit is as follows: kilometers per hour, the parameters in the first column are accelerator opening values, the other parameters are corrected values of upslope gears of the automatic transmission corresponding to vehicle running speed values and accelerator opening degrees, and the detailed parameters in the mapping table 3 are finally obtained according to test calibration;

mapping table 3

	30	40	50	60	70	80
							15	-1	-1	-1	-1	-1	-1
20	-1	-1	-1	-1	-1	-1
							25	-1	-1	-1	-1	-1	-1
30	-1	-1	-1	-1	-1	-1
							35	-1	-1	-1	-1	-1	-1
40	-1	-1	-1	-1	-1	-1

And step 9: calculating the highest gear of the automatic transmission in the process of ascending a slope, wherein the highest gear of the automatic transmission in the process of ascending the slope is obtained through the basic ascending gear and the corrected value of the ascending gear of the automatic transmission, namely the sum of the corrected values of the basic ascending gear and the ascending gear of the automatic transmission is equal to the highest gear of the automatic transmission in the process of ascending the slope; the highest gear in the uphill process of the automatic transmission refers to the highest gear allowed by the automatic transmission in the uphill process of the vehicle, namely, the gear of the automatic transmission is not allowed to be higher than the highest gear in the uphill process of the automatic transmission, so that frequent gear shifting is avoided;

step 10: and (3) judging that the vehicle enters the top of the slope driving process, namely when the current slope angle is smaller than a second uphill angle set value for the first time, the vehicle enters the top of the slope driving process, wherein the second uphill angle set value is 2.

Step 11: judging the end of the whole process of ascending through the road sign at the current time when the vehicle runs, namely changing the road sign at the current time from the top sign of the slope to the bottom sign of the non-top slope, and ending the whole process of ascending;

the control method of the second part, namely the whole stage with the slope bottom in front, comprises the following steps:

step 12: judging that the vehicle enters a process of preparing downhill driving, and judging that the vehicle enters the process of preparing downhill driving according to the slope bottom mark appearing for the first time in the road marks at a plurality of points within a set distance in front of the current position;

step 13: acquiring a maximum downhill angle, wherein the maximum downhill angle is acquired through ramp angles of a plurality of points within a set distance ahead, and the maximum downhill angle refers to the maximum ramp angle of a road in the process of driving on a downhill ahead;

step 14: in the process that the vehicle is ready to run downhill, whether the automatic transmission enters a neutral gear sliding state or not is judged according to the current gear and the vehicle running speed of the automatic transmission, and the judgment conditions are as follows: the current vehicle travel speed is between the first vehicle travel coast speed rating and the second vehicle travel coast speed rating; when the judgment condition is met, the automatic transmission enters a neutral gear and the vehicle enters a sliding state, when the judgment condition cannot be met, the gear of the automatic transmission exits the neutral gear, the vehicle exits the neutral gear sliding state, the first vehicle running sliding speed standard value refers to the lowest speed of the vehicle allowed to slide, the second vehicle running sliding speed standard value refers to the highest speed of the vehicle allowed to slide, the first vehicle running sliding speed standard value is 20, and the second vehicle running sliding speed standard value is 70;

step 15: judging that the vehicle enters a downhill process, namely judging that the vehicle enters the downhill process when the absolute value of the slope angle at the current driving moment of the vehicle is larger than a first downhill angle set value; the first downward slope angle set value is 5;

step 16: in the process of downhill driving of a vehicle, acquiring the highest gear of an automatic transmission allowed in the process of downhill driving, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is acquired by a mapping table 4, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is the gear which is not allowed in the process of downhill driving and is higher than the highest gear of the automatic transmission allowed in the process of downhill driving, so that an engine outputs certain braking force in the process of downhill driving of the vehicle, the highest gear of the automatic transmission allowed in the process of downhill driving is used for limiting gear shifting of the automatic transmission, and if the target gear of the automatic transmission is larger than the highest gear of the automatic transmission allowed in the process of downhill driving, the automatic transmission does not shift gears; in the mapping table 4, the parameter in the first row is a vehicle running speed value, unit: kilometers/hour, the parameters of the first column are the maximum downhill angle, unit: the other parameters are the highest gear of the automatic transmission allowed in the downhill driving process corresponding to the vehicle driving speed value and the maximum downhill angle, and the detailed parameters in the mapping table 4 are finally obtained according to test calibration;

mapping table 4

	30	40	50	60	70	80
							-1	5	5	5	5	5	5
-3	5	5	5	5	5	5
							-5	5	5	5	5	5	5
-7	5	5	5	5	5	5
							-10	5	5	5	5	5	5
-15	5	5	5	5	5	5

And step 17: judging that the vehicle enters a slope bottom driving process through the slope angle of the vehicle at the current driving moment, namely judging that the vehicle enters the slope bottom driving process when the absolute value of the slope angle is smaller than a second downhill angle set value; the second downhill angle setting value is 2;

step 18: and judging the end of the whole process of the downhill through the road sign at the current driving moment of the vehicle, namely changing the road sign at the current driving moment from the slope bottom sign to the non-slope top slope bottom sign, and ending the whole process of the downhill.

The invention provides a gear shifting control method of an automatic transmission based on front road information. According to the ramp angles of a plurality of points in the front set distance and the road signs of a plurality of points in the front set distance, the ramp angle of the vehicle at the current driving moment and the road signs of the vehicle at the current driving moment realize the gear control of the automatic transmission in the processes of uphill preparation, uphill process, hill top process, downhill preparation, downhill process and slope bottom, thereby realizing the acceleration and early upshift before the uphill, avoiding frequent gear shifting in the uphill process, putting the automatic transmission in neutral gear in advance before the downhill, maintaining the engine to have the function of certain braking force in the downhill process, putting the automatic transmission in the optimal gear, and improving the fuel economy and the dynamic property of the vehicle.

Drawings

The invention is further described with reference to the accompanying drawings in which:

FIG. 1 is a flow chart illustrating a method for controlling shifting of an automatic transmission based on road information according to the present invention.

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

fig. 1 is a flowchart of a method of controlling a shift of an automatic transmission based on front road information according to an embodiment of the present invention. As shown in fig. 1, the present embodiment provides a method for controlling shifting of an automatic transmission based on front road information, including the steps of:

the method comprises two stages, namely a first stage and a second stage, wherein the first stage and the second stage are in a sequential relationship, namely the second stage is carried out after the first stage is completed, the first stage is the whole stage with a slope top in front, and the second stage is the whole stage with a slope bottom in front;

the control process of the first stage, namely the whole stage with the front slope top, is as follows:

step 1: judging that the vehicle enters a process of preparing for uphill driving, namely judging that the vehicle enters the process of preparing for uphill driving when a slope top mark appears for the first time in road marks at a plurality of points within a set distance in front of the current position; the road signs are divided into three kinds, namely non-top slope bottom signs, top signs and bottom signs;

step 2: acquiring a horizontal driving distance and a maximum uphill angle before uphill, wherein the horizontal driving distance and the maximum uphill angle before uphill are acquired through GPS information, and the maximum uphill angle is acquired through ramp angles of a plurality of points in a set distance in front, wherein the maximum uphill angle refers to the maximum ramp angle of a road in the process of finishing uphill driving;

and step 3: acquiring shift point offset, wherein the shift point offset is acquired through a mapping table 1, the horizontal distance of driving before an uphill is small, the larger the maximum uphill angle is, the larger the shift point offset is, and in the mapping table 1, the parameter of a first row is the horizontal distance of driving before the uphill, and the unit is as follows: meter, the parameters of the first column are the maximum uphill angle, unit: the other parameters are the horizontal distance of driving before an uphill slope and the shift point offset corresponding to the maximum uphill slope angle, and the detailed parameters in the mapping table 1 are finally obtained according to test calibration;

mapping table 1

	100	300	700	1200	1500	2000
							1	-5	-5	-5	-5	-5	-5
3	-5	-5	-5	-5	-5	-5
							5	-5	-5	-5	-5	-5	-5
7	-5	-5	-5	-5	-5	-5
							10	-5	-5	-5	-5	-5	-5
15	-5	-5	-5	-5	-5	-5

And 4, step 4: acquiring a basic shift point of the current gear of the automatic transmission, wherein the basic shift point of the current gear of the automatic transmission is acquired through a mapping table 2; that is to say, according to the current gear and the accelerator opening of the automatic transmission in the mapping table 2, the basic shift point of the corresponding current gear of the automatic transmission is searched, in the mapping table 2, the parameter of the first row is the current gear of the automatic transmission, the parameter of the first column is the accelerator opening value, and the other parameters are the accelerator opening value and the basic shift point of each gear corresponding to the current gear of the automatic transmission, the unit: at kilometer/hour, the detailed parameters in the mapping table 2 are finally obtained according to test calibration;

mapping table 2

	1	2	3	4	5	6
							10	20	30	40	50	60	70
30	20	30	40	50	60	70
							50	20	30	40	50	60	70
70	20	30	40	50	60	70
							90	20	30	40	50	60	70
100	20	30	40	50	60	70

And 5: acquiring a target shift point, wherein the target shift point is equal to the sum of the basic shift point of the current gear calculated in the step 4 and the shift point offset calculated in the step 3; in the process of preparing the vehicle to run uphill, whether the automatic transmission needs to be shifted up or down is judged by comparing the current vehicle running speed with the target gear shifting point, namely, if the current running speed is greater than the target gear shifting point, the automatic transmission is shifted up; if the current running speed is less than the target gear shifting point, the automatic transmission performs downshifting;

step 6: judging that the vehicle enters an uphill driving process, namely judging that the vehicle enters the uphill driving process when the current ramp angle is larger than a first uphill angle set value for the first time, wherein the time is the time of entering the uphill driving for the first time; the current time ramp angle is the actual road ramp angle of the position of the vehicle at the current time acquired by the GPS; the first uphill angle set value is 5, which is used for judging that the vehicle enters the uphill driving process.

And 7: acquiring a gear at the first uphill driving moment, namely a basic uphill gear;

and 8: acquiring an uphill gear correction value of the automatic transmission, wherein the uphill gear correction value of the automatic transmission is acquired through a mapping table 3, and in the mapping table 3, a parameter of a first row is a vehicle running speed value, and a unit is as follows: kilometers per hour, the parameters in the first column are accelerator opening values, the other parameters are corrected values of upslope gears of the automatic transmission corresponding to vehicle running speed values and accelerator opening degrees, and the detailed parameters in the mapping table 3 are finally obtained according to test calibration;

mapping table 3

And step 9: calculating the highest gear of the automatic transmission in the process of ascending a slope, wherein the highest gear of the automatic transmission in the process of ascending the slope is obtained through the basic ascending gear and the corrected value of the ascending gear of the automatic transmission, namely the sum of the corrected values of the basic ascending gear and the ascending gear of the automatic transmission is equal to the highest gear of the automatic transmission in the process of ascending the slope; the highest gear in the uphill process of the automatic transmission refers to the highest gear allowed by the automatic transmission in the uphill process of the vehicle, namely, the gear of the automatic transmission is not allowed to be higher than the highest gear in the uphill process of the automatic transmission, so that frequent gear shifting is avoided;

step 10: and (3) judging that the vehicle enters the top of the slope driving process, namely when the current slope angle is smaller than a second uphill angle set value for the first time, the vehicle enters the top of the slope driving process, wherein the second uphill angle set value is 2.

Step 11: judging the end of the whole process of ascending through the road sign at the current time when the vehicle runs, namely changing the road sign at the current time from the top sign of the slope to the bottom sign of the non-top slope, and ending the whole process of ascending;

the control method of the second part, namely the whole stage with the slope bottom in front, comprises the following steps:

step 12: judging that the vehicle enters a process of preparing downhill driving, and judging that the vehicle enters the process of preparing downhill driving according to the slope bottom mark appearing for the first time in the road marks at a plurality of points within a set distance in front of the current position;

step 13: acquiring a maximum downhill angle, wherein the maximum downhill angle is acquired through ramp angles of a plurality of points within a set distance ahead, and the maximum downhill angle refers to the maximum ramp angle of a road in the process of driving on a downhill ahead;

step 14: in the process that the vehicle is ready to run downhill, whether the automatic transmission enters a neutral gear sliding state or not is judged according to the current gear and the vehicle running speed of the automatic transmission, and the judgment conditions are as follows: the current vehicle travel speed is between the first vehicle travel coast speed rating and the second vehicle travel coast speed rating; when the judgment condition is met, the automatic transmission enters a neutral gear and the vehicle enters a sliding state, when the judgment condition cannot be met, the gear of the automatic transmission exits the neutral gear, the vehicle exits the neutral gear sliding state, the first vehicle running sliding speed standard value refers to the lowest speed of the vehicle allowed to slide, the second vehicle running sliding speed standard value refers to the highest speed of the vehicle allowed to slide, the first vehicle running sliding speed standard value is 20, and the second vehicle running sliding speed standard value is 70;

step 15: judging that the vehicle enters a downhill process, namely judging that the vehicle enters the downhill process when the absolute value of the slope angle at the current driving moment of the vehicle is larger than a first downhill angle set value; the first downward slope angle set value is 5;

step 16: in the process of downhill driving of a vehicle, acquiring the highest gear of an automatic transmission allowed in the process of downhill driving, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is acquired by a mapping table 4, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is the gear which is not allowed in the process of downhill driving and is higher than the highest gear of the automatic transmission allowed in the process of downhill driving, so that an engine outputs certain braking force in the process of downhill driving of the vehicle, the highest gear of the automatic transmission allowed in the process of downhill driving is used for limiting gear shifting of the automatic transmission, and if the target gear of the automatic transmission is larger than the highest gear of the automatic transmission allowed in the process of downhill driving, the automatic transmission does not shift gears; in the mapping table 4, the parameter in the first row is a vehicle running speed value, unit: kilometers/hour, the parameters of the first column are the maximum downhill angle, unit: the other parameters are the highest gear of the automatic transmission allowed in the downhill driving process corresponding to the vehicle driving speed value and the maximum downhill angle, and the detailed parameters in the mapping table 4 are finally obtained according to test calibration;

mapping table 4

	30	40	50	60	70	80
							-1	5	5	5	5	5	5
-3	5	5	5	5	5	5
							-5	5	5	5	5	5	5
-7	5	5	5	5	5	5
							-10	5	5	5	5	5	5
-15	5	5	5	5	5	5

And step 17: judging that the vehicle enters a slope bottom driving process through the slope angle of the vehicle at the current driving moment, namely judging that the vehicle enters the slope bottom driving process when the absolute value of the slope angle is smaller than a second downhill angle set value; the second downhill angle setting value 2 is 2;

step 18: and judging the end of the whole process of the downhill through the road sign at the current driving moment of the vehicle, namely changing the road sign at the current driving moment from the slope bottom sign to the non-slope top slope bottom sign, and ending the whole process of the downhill.

Claims (1)

1. A gear-shifting control method of an automatic transmission based on front road information is characterized by comprising two stages, namely a first stage and a second stage, wherein the first stage and the second stage are in a sequential relation, namely the second stage is carried out after the first stage is completed, the first stage is the whole stage with a top of a slope in front, and the second stage is the whole stage with a bottom of the slope in front;

the control process of the first stage, namely the whole stage with the front slope top, is as follows:

step 1: judging that the vehicle enters a process of preparing for uphill driving, namely judging that the vehicle enters the process of preparing for uphill driving when a slope top mark appears for the first time in road marks at a plurality of points within a set distance in front of the current position; the road signs are divided into three kinds, namely non-top slope bottom signs, top signs and bottom signs;

step 2: acquiring a horizontal driving distance and a maximum uphill angle before uphill, wherein the horizontal driving distance and the maximum uphill angle before uphill are acquired through GPS information, and the maximum uphill angle is acquired through ramp angles of a plurality of points in a set distance in front, wherein the maximum uphill angle refers to the maximum ramp angle of a road in the process of finishing uphill driving;

and step 3: acquiring shift point offset, wherein the shift point offset is acquired through a mapping table 1, the horizontal distance of driving before an uphill is small, the larger the maximum uphill angle is, the larger the shift point offset is, and in the mapping table 1, the parameter of a first row is the horizontal distance of driving before the uphill, and the unit is as follows: rice, the parameters of the first row are the maximum uphill angle, unit: the other parameters are the horizontal distance of driving before an uphill slope and the shift point offset corresponding to the maximum uphill slope angle, and the detailed parameters in the mapping table 1 are finally obtained according to test calibration;

mapping table 1

100 300 700 1200 1500 2000 1 -5 -5 -5 -5 -5 -5 3 -5 -5 -5 -5 -5 -5 5 -5 -5 -5 -5 -5 -5 7 -5 -5 -5 -5 -5 -5 10 -5 -5 -5 -5 -5 -5 15 -5 -5 -5 -5 -5 -5

And 4, step 4: acquiring a basic shift point of the current gear of the automatic transmission, wherein the basic shift point of the current gear of the automatic transmission is acquired through a mapping table 2; that is to say, according to the current gear and the accelerator opening degree of the automatic transmission in the mapping table 2, the basic shift point of the corresponding current gear of the automatic transmission is searched, in the mapping table 2, the parameter of the first row is the current gear of the automatic transmission, the parameter of the first column is the accelerator opening degree value, and the other parameters are the accelerator opening degree value and the basic shift point of each gear corresponding to the current gear of the automatic transmission, the unit: at kilometer/hour, the detailed parameters in the mapping table 2 are finally obtained according to test calibration;

mapping table 2

And 5: acquiring a target shift point, wherein the target shift point is equal to the sum of the basic shift point of the current gear calculated in the step 4 and the shift point offset calculated in the step 3; in the process of preparing the vehicle to run uphill, whether the automatic transmission needs to be shifted up or down is judged by comparing the current vehicle running speed with the target gear shifting point, namely, if the current running speed is greater than the target gear shifting point, the automatic transmission is shifted up; if the current running speed is less than the target gear shifting point, the automatic transmission performs downshifting;

step 6: judging that the vehicle enters an uphill driving process, namely judging that the vehicle enters the uphill driving process when the current ramp angle is larger than a first uphill angle set value for the first time, wherein the time is the time of entering the uphill driving for the first time; the current time ramp angle is the actual road ramp angle of the position of the vehicle at the current time acquired by the GPS; the first uphill angle set value is 5, and the vehicle can be judged to enter the uphill driving process;

and 7: acquiring a gear at the first uphill driving moment, namely a basic uphill gear;

and 8: acquiring an uphill gear correction value of the automatic transmission, wherein the uphill gear correction value of the automatic transmission is acquired through a mapping table 3, and in the mapping table 3, a parameter of a first row is a vehicle running speed value, and a unit is as follows: kilometers per hour, the parameters in the first column are accelerator opening values, the other parameters are corrected values of upslope gears of the automatic transmission corresponding to vehicle running speed values and accelerator opening degrees, and the detailed parameters in the mapping table 3 are finally obtained according to test calibration;

mapping table 3

30 40 50 60 70 80 15 -1 -1 -1 -1 -1 -1 20 -1 -1 -1 -1 -1 -1 25 -1 -1 -1 -1 -1 -1 30 -1 -1 -1 -1 -1 -1 35 -1 -1 -1 -1 -1 -1 40 -1 -1 -1 -1 -1 -1

And step 9: calculating the highest gear of the automatic transmission in the process of ascending a slope, wherein the highest gear of the automatic transmission in the process of ascending the slope is obtained through the basic ascending gear and the corrected value of the ascending gear of the automatic transmission, namely the sum of the corrected values of the basic ascending gear and the ascending gear of the automatic transmission is equal to the highest gear of the automatic transmission in the process of ascending the slope; the highest gear in the uphill process of the automatic transmission refers to the highest gear allowed by the automatic transmission in the uphill process of the vehicle, namely, the gear of the automatic transmission is not allowed to be higher than the highest gear in the uphill process of the automatic transmission, so that frequent gear shifting is avoided;

step 10: judging that the vehicle enters a slope top driving process, namely when the current slope angle is smaller than a second uphill angle set value for the first time, the vehicle enters the slope top driving process, wherein the second uphill angle set value is 2;

step 11: judging the end of the whole process of ascending through the road sign at the current time when the vehicle runs, namely changing the road sign at the current time from the top sign of the slope to the bottom sign of the non-top slope, and ending the whole process of ascending;

the control method of the second part, namely the whole stage with the slope bottom in front, comprises the following steps:

step 12: judging that the vehicle enters a process of preparing downhill driving, and judging that the vehicle enters the process of preparing downhill driving according to the slope bottom mark appearing for the first time in the road marks at a plurality of points within a set distance in front of the current position;

step 13: acquiring a maximum downhill angle, wherein the maximum downhill angle is acquired through ramp angles of a plurality of points within a set distance ahead, and the maximum downhill angle refers to the maximum ramp angle of a road in the process of driving on a downhill ahead;

step 14: in the process that the vehicle is ready to run downhill, whether the automatic transmission enters a neutral gear sliding state or not is judged according to the current gear and the vehicle running speed of the automatic transmission, and the judgment conditions are as follows: the current vehicle running speed is between the first vehicle running coasting speed rating value and the second vehicle running coasting speed rating value; when the judgment condition is met, the automatic transmission enters a neutral gear and the vehicle enters a sliding state, when the judgment condition cannot be met, the gear of the automatic transmission exits the neutral gear, the vehicle exits the neutral gear sliding state, the first vehicle running sliding speed standard value refers to the lowest speed of the vehicle allowed to slide, the second vehicle running sliding speed standard value refers to the highest speed of the vehicle allowed to slide, the first vehicle running sliding speed standard value is 20, and the second vehicle running sliding speed standard value is 70;

step 15: judging that the vehicle enters a downhill process, namely judging that the vehicle enters the downhill process when the absolute value of the slope angle at the current driving moment of the vehicle is larger than a first downhill angle set value; the first downward slope angle set value is 5;

step 16: in the process of downhill driving of a vehicle, acquiring the highest gear of an automatic transmission allowed in the process of downhill driving, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is acquired by a mapping table 4, wherein the highest gear of the automatic transmission allowed in the process of downhill driving is the gear which is not allowed in the process of downhill driving and is higher than the highest gear of the automatic transmission allowed in the process of downhill driving, so that an engine outputs certain braking force in the process of downhill driving of the vehicle, the highest gear of the automatic transmission allowed in the process of downhill driving is used for limiting gear shifting of the automatic transmission, and if the target gear of the automatic transmission is larger than the highest gear of the automatic transmission allowed in the process of downhill driving, the automatic transmission does not shift gears; in the mapping table 4, the parameter in the first row is a vehicle running speed value, unit: kilometers/hour, the parameters of the first column are the maximum downhill angle, unit: the other parameters are the highest gear of the automatic transmission allowed in the downhill driving process corresponding to the vehicle driving speed value and the maximum downhill angle, and the detailed parameters in the mapping table 4 are finally obtained according to test calibration;

mapping table 4

And step 17: judging that the vehicle enters a slope bottom driving process through the slope angle of the vehicle at the current driving moment, namely judging that the vehicle enters the slope bottom driving process when the absolute value of the slope angle is smaller than a second downhill angle set value; the second downhill angle setting value is 2;

step 18: and judging the end of the whole process of the downhill through the road sign at the current driving moment of the vehicle, namely changing the road sign at the current driving moment from the slope bottom sign to the non-slope top slope bottom sign, and ending the whole process of the downhill.

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