Am t upshift control method and vehicle

Abstract

The application discloses an AMT up-hill gear shifting control method and a vehicle. The AMT up-hill gear shifting control method comprises the following steps: the vehicle enters an up-hill working condition; the real-time acceleration of the vehicle is calculated; the running resistance of the vehicle is calculated according to the real-time acceleration of the vehicle; it is judged whether the real-time acceleration of the vehicle is less than a first set acceleration; if the real-time acceleration of the vehicle is less than the first set acceleration, it is judged whether the vehicle can downshift according to the running resistance, the maximum theoretical output torque of the speed reducer after downshifting and the theoretical output speed of the engine after downshifting; if the real-time acceleration of the vehicle is greater than or equal to the first set acceleration, it is judged whether the vehicle can upshift according to the running resistance and the maximum theoretical output torque of the speed reducer after upshifting; and the first set acceleration is greater than or equal to zero. The AMT up-hill gear shifting control method effectively improves the judgment accuracy of whether the vehicle can upshift or downshift in the up-hill process, thereby effectively improving the driving comfort of the driver in the up-hill process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to an AMT upshift control method and a vehicle. BACKGROUND

[0002] The shift schedule of an AMT (Automated Mechanical Transmission) vehicle directly affects the power performance, economy and emission performance of the vehicle, and formulating a reasonable shift strategy is one of the core technologies for developing an automatic transmission of a vehicle. The shift strategy refers to the law of the timing of automatic shifting between two adjacent gears of an automatic transmission changing with control parameters.

[0003] For heavy trucks, tractors and other vehicles with a large number of gears, it is necessary to accurately determine whether the vehicle should drop one gear, two gears or even three gears during uphill driving, otherwise the driver will still feel that the gear is too low or the downshift is not timely during uphill driving. In the prior art, an AMT upshift control method calculates the average acceleration during the power interruption period of the shift process by the rotational speed of the output shaft of the transmission, estimates the road load of the vehicle according to the average acceleration during the power interruption period of the shift process, determines whether to upshift or downshift according to the road load, and determines the number of downshifts or upshifts according to the road load. However, the road load estimated according to the average acceleration during the power interruption period of the shift process has low accuracy, which leads to low accuracy of determining whether to upshift or downshift according to the road load, and low accuracy of determining the number of downshifts or upshifts according to the road load, so the driver will still feel that the gear is too low or the downshift is not timely, and the uphill driving comfort of the driver is low. SUMMARY

[0004] The present application provides an AMT upshift control method and a vehicle to solve the problem of low accuracy of the AMT upshift control method in the prior art, which leads to the driver still feeling that the gear is too low or the downshift is not timely.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] The AMT upshift control method, the engine system includes an engine and a reducer connected to the output end of the engine, which includes:

[0007] The vehicle enters an uphill working condition;

[0008] The real-time acceleration of the vehicle is calculated, and the driving resistance of the vehicle is calculated according to the real-time acceleration of the vehicle;

[0009] It is determined whether the real-time acceleration of the vehicle is less than a first set acceleration;

[0010] If the real-time acceleration of the vehicle is less than the first set acceleration, determining whether the vehicle can downshift according to the driving resistance, the maximum theoretical output torque of the speed reducer after downshifting, and the theoretical output speed of the engine after downshifting;

[0011] If the real-time acceleration of the vehicle is greater than or equal to the first set acceleration, determining whether the vehicle can upshift according to the driving resistance and the maximum theoretical output torque of the speed reducer after upshifting;

[0012] Wherein, the first set acceleration is greater than or equal to zero.

[0013] As a preferred solution of the AMT upshift control method, the specific steps of determining whether the vehicle can downshift according to the driving resistance, the maximum theoretical output torque of the speed reducer after downshifting, and the theoretical output speed of the engine after downshifting include:

[0014] Calculating the first theoretical acceleration after downshifting according to the driving resistance and the first maximum theoretical output torque of the speed reducer after downshifting;

[0015] Determining whether the first theoretical acceleration is less than a second set acceleration;

[0016] If the first theoretical acceleration is greater than or equal to the second set acceleration, determining a first downshift strategy according to the first theoretical output speed of the engine after downshifting, the second theoretical output speed of the engine after downshifting by one, and the third theoretical output speed of the engine after downshifting by two;

[0017] If the first theoretical acceleration is less than the second set acceleration, calculating the second theoretical acceleration after downshifting by two according to the driving resistance and the second maximum theoretical output torque of the speed reducer after downshifting by two;

[0018] Determining whether the second theoretical acceleration is less than the second set acceleration;

[0019] If the second theoretical acceleration is greater than or equal to the second set acceleration, determining a second downshift strategy according to the second theoretical output speed of the engine after downshifting by two and the third theoretical output speed of the engine after downshifting by three;

[0020] If the second theoretical acceleration is less than the second set acceleration, determining a third downshift strategy according to the third theoretical output speed of the engine after downshifting by three;

[0021] Wherein, the second set acceleration is greater than or equal to zero.

[0022] As a preferred solution of the AMT upshift control method, the specific steps of the first downshift strategy include:

[0023] determining whether the first theoretical output rotational speed is less than or equal to a first set rotational speed value;

[0024] if the first theoretical output rotational speed is greater than the first set rotational speed value, the vehicle is not allowed to downshift.

[0025] As a preferred solution of the AMT upshifting control method, if the first theoretical output rotational speed is less than or equal to a first set rotational speed value, the vehicle is allowed to downshift by one gear;

[0026] determining whether the vehicle is allowed to downshift by two gears according to a second theoretical output rotational speed of the engine after downshifting by two gears, and determining whether the vehicle is allowed to downshift by three gears according to a third theoretical output rotational speed of the engine after downshifting by three gears;

[0027] if the vehicle is allowed to downshift by one gear, and the vehicle is allowed to downshift by two gears and one or two of the vehicle is allowed to downshift by three gears are simultaneously satisfied, the final downshift of the vehicle is determined according to the minimum value of the fuel consumption value of the vehicle allowed to downshift by one gear, and the fuel consumption value corresponding to one or two of the vehicle allowed to downshift by two gears and the vehicle allowed to downshift by three gears.

[0028] As a preferred solution of the AMT upshifting control method, the specific steps of determining whether the vehicle is allowed to downshift by two gears according to a second theoretical output rotational speed of the engine after downshifting by two gears, and determining whether the vehicle is allowed to downshift by three gears according to a third theoretical output rotational speed of the engine after downshifting by three gears include:

[0029] determining whether the second theoretical output rotational speed is less than or equal to a second set rotational speed value;

[0030] if the second theoretical output rotational speed is less than or equal to the second set rotational speed value, the vehicle is allowed to downshift by two gears;

[0031] if the second theoretical output rotational speed is greater than the second set rotational speed value, the vehicle is not allowed to downshift by two gears;

[0032] determining whether the third theoretical output rotational speed is less than or equal to a third set rotational speed value;

[0033] if the third theoretical output rotational speed is less than or equal to the third set rotational speed value, the vehicle is allowed to downshift by three gears;

[0034] if the third theoretical output rotational speed is greater than the third set rotational speed value, the vehicle is not allowed to downshift by three gears.

[0035] As a preferred solution of the AMT upshifting control method, a first minimum required torque of the engine for overcoming the running resistance when the vehicle downshifts by one gear is calculated, and a first fuel consumption value of the vehicle downshifted by one gear is obtained from the universal table according to the first minimum required torque and the first theoretical output rotational speed;

[0036] calculating a second minimum required torque of the engine for overcoming the running resistance when the vehicle is downshifted to the second gear, and acquiring a second fuel consumption value of the vehicle when downshifted to the second gear from the universal table according to the second minimum required torque and the second theoretical output speed;

[0037] calculating a third minimum required torque of the engine for overcoming the running resistance when the vehicle is downshifted to the third gear, and acquiring a third fuel consumption value of the vehicle when downshifted to the third gear from the universal table according to the third minimum required torque and the third theoretical output speed;

[0038] wherein the universal table is a table formed by a required torque, a theoretical output speed and a fuel consumption value.

[0039] As a preferred solution of the AMT upshifting control method, the specific steps of the second downshifting strategy include:

[0040] judging whether the second theoretical output speed is less than or equal to a second set speed value;

[0041] if the second theoretical output speed is greater than the second set speed value, judging whether the first theoretical output speed is less than or equal to a first set speed value; if the first theoretical output speed is less than or equal to the first set speed value, allowing the vehicle to be downshifted to the first gear; controlling the vehicle to be downshifted to the first gear; and if the first theoretical output speed is greater than the first set speed value, not allowing the vehicle to be downshifted.

[0042] As a preferred solution of the AMT upshifting control method, if the second theoretical output speed is less than or equal to the second set speed value, the vehicle is allowed to be downshifted to the second gear.

[0043] judging whether a third theoretical output speed of the engine after downshifting to the third gear is less than or equal to a third set speed value;

[0044] if the third theoretical output speed is less than or equal to the third set speed value, the vehicle is allowed to be downshifted to the third gear;

[0045] if the third theoretical output speed is greater than the third set speed value, the vehicle is not allowed to be downshifted.

[0046] if the vehicle is allowed to be downshifted to the second gear and the vehicle is allowed to be downshifted to the third gear at the same time, a final downshifting of the vehicle is determined according to a minimum value of the fuel consumption value of the vehicle allowed to be downshifted to the second gear and the fuel consumption value of the vehicle allowed to be downshifted to the third gear.

[0047] As a preferred solution of the AMT upshifting control method, the specific steps of the third downshifting strategy include:

[0048] judging whether the third theoretical output speed is less than or equal to the third set speed value;

[0049] If the third theoretical output rotating speed is less than or equal to a third set rotating speed value, the vehicle is allowed to reduce the gear by three gears; the vehicle is controlled to reduce the gear by three gears;

[0050] If the third theoretical output rotating speed is greater than the third set rotating speed value, it is determined whether the second theoretical output rotating speed is less than or equal to a second set rotating speed value; if the second theoretical output rotating speed is less than or equal to the second set rotating speed value, the vehicle is allowed to reduce the gear by two gears; the vehicle is controlled to reduce the gear by two gears; if the second theoretical output rotating speed is greater than the second set rotating speed value, it is determined whether the first theoretical output rotating speed is less than or equal to a first set rotating speed value; if the first theoretical output rotating speed is less than or equal to the first set rotating speed value, the vehicle is allowed to reduce the gear by one gear; the vehicle is controlled to reduce the gear by one gear; if the first theoretical output rotating speed is greater than the first set rotating speed value, the vehicle is not allowed to reduce the gear.

[0051] A vehicle for implementing the AMT up-hill gear shifting control method described above, the vehicle comprising the engine system.

[0052] The present application has the following beneficial effects:

[0053] The present application aims to provide an AMT up-hill gear shifting control method and a vehicle, which, when the vehicle enters an up-hill working condition and wants to shift gears, calculates the real-time acceleration of the vehicle; calculates the running resistance of the vehicle according to the real-time acceleration of the vehicle; determines whether the real-time acceleration of the vehicle is less than a first set acceleration; if the real-time acceleration of the vehicle is less than the first set acceleration, it indicates that the actual output torque of the vehicle at the current gear cannot meet the running requirement of the vehicle, at this time, it is determined whether the vehicle can reduce the gear according to the running resistance, the maximum theoretical output torque of the reducer after gear reduction, and the theoretical output rotating speed of the engine after gear reduction; if the vehicle can reduce the gear, the vehicle reduces the gear; if the vehicle cannot reduce the gear, the vehicle keeps running at the original gear; if the real-time acceleration of the vehicle is greater than or equal to the first set acceleration, and the first set acceleration is greater than or equal to zero, it indicates that the actual output torque of the vehicle at the current gear can meet the running requirement of the vehicle, at this time, it is determined whether the vehicle can increase the gear according to the running resistance and the maximum theoretical output torque of the reducer after gear increase; if the vehicle can increase the gear, the vehicle increases the gear; if the vehicle cannot increase the gear, the vehicle keeps running at the original gear. In the AMT up-hill gear shifting control method, whether the vehicle can reduce the gear is determined by the real-time acceleration of the vehicle, the running resistance, the maximum theoretical output torque of the reducer after gear reduction, and the theoretical output rotating speed of the engine after gear reduction; whether the vehicle can increase the gear is determined by the real-time acceleration of the vehicle, the running resistance, and the maximum theoretical output torque of the reducer after gear increase. Compared with the prior art which determines whether the vehicle can increase or reduce the gear during the up-hill process by road load, the determination accuracy of whether the vehicle can increase or reduce the gear during the up-hill process is effectively improved, thereby effectively improving the driving comfort of the driver during the up-hill process. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 This is the process of the AMT uphill shift control method provided by the specific embodiment of the present invention Figure 1 ;

[0055] Figure 2 This is the process of the AMT uphill shift control method provided by the specific embodiment of the present invention Figure 2 ;

[0056] Figure 3 This is the process of the AMT uphill shift control method provided by the specific embodiment of the present invention Figure 3 ;

[0057] Figure 4 This is the process of the AMT uphill shift control method provided by the specific embodiment of the present invention Figure 4 . DETAILED DESCRIPTION

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0059] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0060] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0061] In the description of the present embodiment, the terms "upper", "lower", "right", "left", and the like, positional or locational relations are based on the positional or locational relations shown in the drawings, and are merely for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are merely used to distinguish in description and have no special meaning.

[0062] An AMT upshift control method in the prior art calculates the average acceleration during power interruption in the shift process from the rotational speed of the transmission output shaft, then estimates the road load of the vehicle according to the average acceleration during power interruption in the shift process, and judges whether the vehicle can upshift or downshift according to the road load, and judges how many gears to downshift or upshift according to the road load. However, the AMT upshift control method according to the road load estimates the road load from the average acceleration during power interruption in the shift process, resulting in low accuracy of judging whether the vehicle can upshift or downshift according to the road load, and how many gears to downshift or upshift according to the road load, so that the driver still feels that the upshift is not timely or the gear is too low, and the upshift driving comfort of the driver is low.

[0063] Therefore, the present application provides an AMT upshift control method, wherein the engine system comprises an engine and a reducer connected to the output end of the engine, as shown in Figure 1 and Figure 2 The AMT upshift control method comprises:

[0064] The vehicle enters an upshift working condition.

[0065] The real-time acceleration of the vehicle is calculated, and the driving resistance of the vehicle is calculated according to the real-time acceleration of the vehicle. The real-time acceleration of the vehicle is calculated according to the vehicle speed, the output rotational speed of the engine, or the output rotational speed of the reducer, and the formula for calculating the real-time acceleration of the vehicle according to the vehicle speed, the output rotational speed of the engine, or the output rotational speed of the reducer is prior art and will not be described here. The specific calculation formula for calculating the driving resistance of the vehicle according to the real-time acceleration of the vehicle is prior art and will not be described here. The driving resistance at least includes friction resistance, wind resistance, vehicle weight, and cargo weight.

[0066] It is judged whether the real-time acceleration of the vehicle is less than a first set acceleration. The first set acceleration is an empirical value obtained from a large number of experiments in advance.

[0067] If the real-time acceleration of the vehicle is less than the first set acceleration, it is judged whether the vehicle can downshift according to the driving resistance, the maximum theoretical output torque of the reducer after downshifting, and the theoretical output rotational speed of the engine after downshifting.

[0068] The first set acceleration is greater than or equal to zero. The power requirement of the vehicle after the gear shifting is ensured, so that the vehicle can normally proceed after the gear shifting.

[0069] The specific steps of determining whether the vehicle can be down-shifted according to the driving resistance, the maximum theoretical output torque of the speed reducer after the down-shifting, and the theoretical output speed of the engine after the down-shifting include: Figure 2 Figure 3 The specific steps of determining whether the vehicle can be down-shifted according to the driving resistance, the maximum theoretical output torque of the speed reducer after the down-shifting, and the theoretical output speed of the engine after the down-shifting include:

[0070] The first theoretical acceleration after the down-shifting is calculated according to the driving resistance and the first maximum theoretical output torque of the speed reducer after the down-shifting.

[0071] The first theoretical acceleration is determined whether it is less than a second set acceleration. The second set acceleration is greater than or equal to zero. The power requirement of the vehicle after the gear shifting is ensured, so that the vehicle can normally proceed after the gear shifting. The second set acceleration is an empirical value obtained from a large number of experiments in the early stage.

[0072] If the first theoretical acceleration is greater than or equal to the second set acceleration, the first down-shifting strategy is determined according to the first theoretical output speed of the engine after the down-shifting, the second theoretical output speed of the engine after the down-shifting, and the third theoretical output speed of the engine after the down-shifting.

[0073] The specific steps of the first down-shifting strategy include:

[0074] The first theoretical output speed is determined whether it is less than or equal to a first set speed value. The first set speed value is an empirical value obtained from a large number of experiments in the early stage.

[0075] If the first theoretical output speed is greater than the first set speed value, the vehicle is not allowed to be down-shifted. If the vehicle is down-shifted when the first theoretical output speed is greater than the first set speed value, the vehicle needs to be up-shifted again after the down-shifting, resulting in the phenomenon of frequent up-shifting and down-shifting of the vehicle. Therefore, the vehicle is not allowed to be down-shifted when the first theoretical output speed is greater than the first set speed value.

[0076] If the first theoretical output speed is less than or equal to the first set speed value, the vehicle is allowed to be down-shifted.

[0077] It is determined whether the vehicle is allowed to be down-shifted according to the second theoretical output speed of the engine after the down-shifting, and whether the vehicle is allowed to be down-shifted according to the third theoretical output speed of the engine after the down-shifting.

[0078] The specific steps of determining whether the vehicle is allowed to be down-shifted according to the second theoretical output speed of the engine after the down-shifting, and whether the vehicle is allowed to be down-shifted according to the third theoretical output speed of the engine after the down-shifting include:

[0079] It is determined whether the second theoretical output speed is less than or equal to a second set speed value.​

[0080] If the second theoretical output rotational speed is less than or equal to the second set rotational speed value, the vehicle is allowed to downshift to second gear.

[0081] If the second theoretical output rotational speed is greater than the second set rotational speed value, the vehicle is not allowed to downshift to second gear.

[0082] It is judged whether the third theoretical output rotational speed is less than or equal to the third set rotational speed value.

[0083] If the third theoretical output rotational speed is less than or equal to the third set rotational speed value, the vehicle is allowed to downshift to third gear.

[0084] If the third theoretical output rotational speed is greater than the third set rotational speed value, the vehicle is not allowed to downshift to third gear.

[0085] In order to avoid the situation that it is not known which gear is the optimal gear when one or two of the following conditions are met: the vehicle is allowed to downshift to first gear, the vehicle is allowed to downshift to second gear, and the vehicle is allowed to downshift to third gear. The AMT upshift control method further comprises the following steps:

[0086] If one or two of the following conditions are met: the vehicle is allowed to downshift to first gear, the vehicle is allowed to downshift to second gear, and the vehicle is allowed to downshift to third gear, the final gear of the vehicle is determined according to the minimum value of the fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to first gear, and the fuel consumption value corresponding to one or two of the conditions that the vehicle is allowed to downshift to second gear and the vehicle is allowed to downshift to third gear.

[0087] The fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to first gear is the first fuel consumption value; the fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to second gear is the second fuel consumption value; and the fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to third gear is the third fuel consumption value.

[0088] Specifically, as shown in Figure 3 If the conditions that the vehicle is allowed to downshift to first gear, the vehicle is allowed to downshift to second gear, and the vehicle is allowed to downshift to third gear are all met, the final gear of the vehicle is determined according to the minimum value of the first fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to first gear, the second fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to second gear, and the third fuel consumption value corresponding to the condition that the vehicle is allowed to downshift to third gear.

[0089] Specifically, as shown in Figure 3 The minimum value of the first fuel consumption value, the second fuel consumption value, and the third fuel consumption value is compared. If the first fuel consumption value is the minimum, the vehicle is controlled to downshift to first gear. If the second fuel consumption value is the minimum, the vehicle is controlled to downshift to second gear. If the third fuel consumption value is the minimum, the vehicle is controlled to downshift to third gear. It can be understood that the vehicle is downshifted to the gear with the minimum fuel consumption, thereby effectively reducing fuel consumption.

[0090] Specifically, if the vehicle is allowed to downshift one gear and is allowed to downshift two gears, the final downshift of the vehicle is determined according to the minimum value between the first fuel consumption value of the vehicle downshifting one gear and the second fuel consumption value of the vehicle downshifting two gears. If the vehicle is allowed to downshift one gear and is allowed to downshift three gears, the final downshift of the vehicle is determined according to the minimum value between the first fuel consumption value of the vehicle downshifting one gear and the third fuel consumption value of the vehicle downshifting three gears.

[0091] If the vehicle is allowed to downshift one gear only, the vehicle is controlled to downshift one gear.

[0092] It can be understood that when the vehicle meets the condition of downshifting one gear, it must meet the conditions of downshifting two gears and downshifting three gears. Therefore, after determining that the vehicle is allowed to downshift one gear, it is determined whether the vehicle is allowed to downshift two gears and three gears. The final downshift of the vehicle is determined according to the minimum value between the first fuel consumption value of the vehicle downshifting one gear and the corresponding fuel consumption value of the vehicle downshifting two gears and the vehicle downshifting three gears, which can effectively reduce fuel consumption.

[0093] Specifically, the first minimum required torque of the engine to overcome the running resistance when the vehicle downshifts one gear is calculated, and the first fuel consumption value of the vehicle downshifting one gear is obtained from the universal table according to the first minimum required torque and the first theoretical output speed. The second minimum required torque of the engine to overcome the running resistance when the vehicle downshifts two gears is calculated, and the second fuel consumption value of the vehicle downshifting two gears is obtained from the universal table according to the second minimum required torque and the second theoretical output speed. The third minimum required torque of the engine to overcome the running resistance when the vehicle downshifts three gears is calculated, and the third fuel consumption value of the vehicle downshifting three gears is obtained from the universal table according to the third minimum required torque and the third theoretical output speed. The universal table is a table formed according to a large number of experiments in the early stage.

[0094] The calculation formula of the theoretical required torque and the theoretical output speed of each gear belongs to the prior art and will not be described here. The calculation formula of the first theoretical acceleration after the vehicle downshifts one gear according to the running resistance and the first maximum theoretical output torque of the reducer after the vehicle downshifts one gear, and the calculation formula of the second theoretical acceleration after the vehicle downshifts two gears according to the running resistance and the second maximum theoretical output torque of the reducer after the vehicle downshifts two gears both belong to the prior art and will not be described here. The calculation formula of the first maximum theoretical output torque and the calculation formula of the second maximum theoretical output torque both belong to the prior art and will not be described here.

[0095] If the first theoretical acceleration is less than the second set acceleration, a second theoretical acceleration after downshifting to the second gear is calculated according to the running resistance and the second maximum theoretical output torque of the downshifting second gear reducer. It can be understood that if the first theoretical acceleration is less than the second set acceleration, it indicates that the vehicle is suitable for downshifting to the second gear, and at this time, the second theoretical acceleration after downshifting to the second gear is calculated according to the running resistance and the second maximum theoretical output torque of the downshifting second gear reducer, and whether the vehicle can downshift to the second gear is determined according to the second theoretical acceleration.

[0096] It is determined whether the second theoretical acceleration is less than the second set acceleration.

[0097] If the second theoretical acceleration is greater than or equal to the second set acceleration, a second downshifting strategy is determined according to the second theoretical output speed of the engine after downshifting to the second gear and the third theoretical output speed of the engine after downshifting to the third gear.

[0098] The specific steps of the second downshifting strategy include:

[0099] It is determined whether the second theoretical output speed is less than or equal to the second set speed value.

[0100] If the second theoretical output speed is greater than the second set speed value, it is determined whether the first theoretical output speed is less than or equal to the first set speed value; if the first theoretical output speed is less than or equal to the first set speed value, the vehicle is allowed to downshift to the first gear; the vehicle is controlled to downshift to the first gear; and if the first theoretical output speed is greater than the first set speed value, the vehicle is not allowed to downshift. In this way, when the second theoretical output speed is greater than the second set speed value, it can be determined that the vehicle downshifts to the first gear, or is not allowed to downshift, and the original gear is maintained.

[0101] If the second theoretical output speed is less than or equal to the second set speed value, the vehicle is allowed to downshift to the second gear.

[0102] It is determined whether the third theoretical output speed of the engine after downshifting to the third gear is less than or equal to the third set speed.

[0103] If the third theoretical output speed is less than or equal to the third set speed value, the vehicle is allowed to downshift to the third gear.

[0104] If the third theoretical output speed is greater than the third set speed value, the vehicle is not allowed to downshift to the third gear.

[0105] If the vehicle is allowed to downshift to the second gear and the vehicle is allowed to downshift to the third gear, the final downshift of the vehicle is determined according to the minimum value of the fuel consumption value of the vehicle downshifting to the second gear and the fuel consumption value of the vehicle downshifting to the third gear. That is, the final downshift of the vehicle is determined according to the minimum value of the second fuel consumption value of the vehicle downshifting to the second gear and the third fuel consumption value of the vehicle downshifting to the third gear. Specifically, the minimum value of the second fuel consumption value and the third fuel consumption value is compared. If the second fuel consumption value is the minimum, the vehicle is controlled to downshift to the second gear. If the third fuel consumption value is the minimum, the vehicle is controlled to downshift to the third gear. If the vehicle only meets the condition of allowing the vehicle to downshift to the second gear, the vehicle is controlled to downshift to the second gear.

[0106] It can be understood that when the vehicle meets the condition of downshifting to the second gear, the condition of downshifting to the third gear is also met. Therefore, after determining that the vehicle is allowed to downshift to the second gear, it is further determined whether the vehicle is allowed to downshift to the third gear. The final downshift of the vehicle is determined according to the minimum value of the second fuel consumption value of the vehicle downshifting to the second gear and the third fuel consumption value of the vehicle downshifting to the third gear, which can effectively reduce fuel consumption.

[0107] If the second theoretical acceleration is less than the second set acceleration, a third downshift strategy is determined according to the third theoretical output speed of the engine after downshifting to the third gear. It can be understood that the second theoretical acceleration being less than the second set acceleration indicates that the vehicle is more suitable for downshifting to the third gear. At this time, whether to downshift to the third gear is determined according to the third theoretical output speed of the engine after downshifting to the third gear.

[0108] The specific steps of the third downshift strategy include:

[0109] It is determined whether the third theoretical output speed is less than or equal to a third set speed value. The third set speed is an empirical value obtained from a large number of experiments in the early stage.

[0110] If the third theoretical output speed is less than or equal to the third set speed value, the vehicle is allowed to downshift to the third gear, and the vehicle is controlled to downshift to the third gear.

[0111] If the third theoretical output speed is greater than the third set speed value, it is determined whether the second theoretical output speed is less than or equal to a second set speed value. If the second theoretical output speed is less than or equal to the second set speed value, the vehicle is allowed to downshift to the second gear, and the vehicle is controlled to downshift to the second gear. If the second theoretical output speed is greater than the second set speed value, it is determined whether the first theoretical output speed is less than or equal to a first set speed value. If the first theoretical output speed is less than or equal to the first set speed value, the vehicle is allowed to downshift to the first gear, and the vehicle is controlled to downshift to the first gear. If the first theoretical output speed is greater than the first set speed value, the vehicle is not allowed to downshift.

[0112] In this way, when the third theoretical output speed is greater than the third set speed value, it can be determined that the vehicle is downshifting to the first gear, downshifting to the second gear, or not allowed to downshift, and the original gear position is maintained.

[0113] If the real-time acceleration of the vehicle is greater than or equal to the first set acceleration, whether the vehicle can be upshifted is determined according to the running resistance and the maximum theoretical output torque of the decelerator after upshifting.

[0114] As shown in Figure 1 and Figure 4 the specific steps of determining whether to upshift by the third theoretical acceleration after upshifting include:

[0115] The third theoretical acceleration after upshifting is calculated according to the running resistance and the third maximum theoretical output torque of the decelerator after upshifting. The calculation formula for calculating the third theoretical acceleration after upshifting according to the running resistance and the third maximum theoretical output torque of the decelerator after upshifting is prior art and will not be described here. The calculation formula for calculating the third maximum theoretical output torque is prior art and will not be described here.

[0116] Whether to upshift is determined according to the third theoretical acceleration after upshifting.

[0117] The specific steps of determining whether to upshift by the third theoretical acceleration after upshifting include:

[0118] Whether the third theoretical acceleration is less than the third set acceleration is determined.

[0119] If the third theoretical acceleration is greater than or equal to the third set acceleration, the vehicle is allowed to upshift, and the vehicle is controlled to upshift.

[0120] If the third theoretical acceleration is less than the third set acceleration, the vehicle is not allowed to upshift.

[0121] The third set acceleration is greater than or equal to zero. The power demand of the vehicle after upshifting is ensured, so that the vehicle can normally proceed after upshifting.

[0122] In this way, the determination of whether the vehicle downshifts by one gear, downshifts by two gears, downshifts by three gears, upshifts by one gear, or is not allowed to upshift or downshift, and maintains the original gear position, is completed.

[0123] Therefore, the AMT upshifting control method determines whether the vehicle can downshift by the real-time acceleration of the vehicle, the running resistance, the maximum theoretical output torque of the decelerator after downshifting, and the theoretical output speed of the engine after downshifting, and determines whether the vehicle can upshift by the real-time acceleration of the vehicle, the running resistance, and the maximum theoretical output torque of the decelerator after upshifting. Compared with the prior art of determining whether the vehicle can upshift or downshift during uphill driving by road load, the accuracy of determining whether the vehicle can upshift or downshift during uphill driving is effectively improved, thereby effectively improving the driving comfort of the driver during uphill driving.

[0124] The application further provides a vehicle for implementing the AMT upshifting control method, the vehicle comprising the engine system, the engine system comprising an engine and a reducer connected to an output end of the engine. The AMT upshifting control method can determine whether the vehicle can shift gears during uphill driving and to which gear the vehicle shifts, and can effectively improve the accuracy of determining whether the vehicle can upshift or downshift during uphill driving, and can effectively improve the driving comfort of the driver during uphill driving.

[0125] Obviously, the above embodiments of the application are merely examples for clear illustration of the application, and are not intended to limit the embodiments of the application. Those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the protection scope of the application. It is unnecessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement within the spirit and principle of the application shall be included in the protection scope of the claims of the application.

Claims

1. An AMT upshift control method, an engine system including an engine and a reduction gear connected to an output end of the engine, characterized by, The method comprises: a vehicle enters an uphill working condition; a real-time acceleration of the vehicle is calculated; a running resistance of the vehicle is calculated according to the real-time acceleration of the vehicle; it is judged whether the real-time acceleration of the vehicle is less than a first set acceleration; if the real-time acceleration of the vehicle is less than the first set acceleration, it is judged whether the vehicle can downshift according to the running resistance, a maximum theoretical output torque of the retarder after downshifting, and a theoretical output speed of the engine after downshifting; if the real-time acceleration of the vehicle is greater than or equal to the first set acceleration, it is judged whether the vehicle can upshift according to the running resistance and a maximum theoretical output torque of the retarder after upshifting; wherein the specific steps of judging whether the vehicle can downshift according to the running resistance, the maximum theoretical output torque of the retarder after downshifting, and the theoretical output speed of the engine after downshifting comprise: a first theoretical acceleration after downshifting by one gear is calculated according to the running resistance and a first maximum theoretical output torque of the retarder after downshifting by one gear; it is judged whether the first theoretical acceleration is less than a second set acceleration; if the first theoretical acceleration is greater than or equal to the second set acceleration, a first downshifting strategy is determined according to a first theoretical output speed of the engine after downshifting by one gear, a second theoretical output speed of the engine after downshifting by two gears, and a third theoretical output speed of the engine after downshifting by three gears; if the first theoretical acceleration is less than the second set acceleration, a second theoretical acceleration after downshifting by two gears is calculated according to the running resistance and a second maximum theoretical output torque of the retarder after downshifting by two gears; it is judged whether the second theoretical acceleration is less than the second set acceleration; if the second theoretical acceleration is greater than or equal to the second set acceleration, a second downshifting strategy is determined according to the second theoretical output speed of the engine after downshifting by two gears and the third theoretical output speed of the engine after downshifting by three gears; if the second theoretical acceleration is less than the second set acceleration, a third downshifting strategy is determined according to the third theoretical output speed of the engine after downshifting by three gears; wherein the first set acceleration is greater than or equal to zero, and the second set acceleration is greater than or equal to zero.

2. The AMT upshift control method of claim 1, wherein, The specific steps of the first downshifting strategy comprise: it is judged whether the first theoretical output speed is less than or equal to a first set speed value; if the first theoretical output speed is greater than the first set speed value, the vehicle is not allowed to downshift.

3. The AMT upshift control method of claim 2, wherein, if the first theoretical output speed is less than or equal to the first set speed value, the vehicle is allowed to downshift by one gear; it is judged whether the vehicle is allowed to downshift by two gears according to the second theoretical output speed of the engine after downshifting by two gears; it is judged whether the vehicle is allowed to downshift by three gears according to the third theoretical output speed of the engine after downshifting by three gears; if the vehicle is allowed to downshift by one gear, and the vehicle is allowed to downshift by two gears and the vehicle is allowed to downshift by three gears at the same time, a final downshifting of the vehicle is determined according to the minimum value of the fuel consumption value of the vehicle allowed to downshift by one gear, and the fuel consumption value of the vehicle allowed to downshift by two gears and the fuel consumption value of the vehicle allowed to downshift by three gears.

4. The AMT upshift control method of claim 3, wherein, it is judged whether the vehicle is allowed to downshift by two gears according to the second theoretical output speed of the engine after downshifting by two gears; The specific steps of judging whether the vehicle is allowed to downshift by three gears according to the third theoretical output speed of the engine after downshifting by three gears comprise: determining whether the second theoretical output rotating speed is less than or equal to a second set rotating speed value; if the second theoretical output rotating speed is less than or equal to the second set rotating speed value, allowing the vehicle to downshift to the second gear; if the second theoretical output rotating speed is greater than the second set rotating speed value, not allowing the vehicle to downshift to the second gear; determining whether the third theoretical output rotating speed is less than or equal to a third set rotating speed value; if the third theoretical output rotating speed is less than or equal to the third set rotating speed value, allowing the vehicle to downshift to the third gear; if the third theoretical output rotating speed is greater than the third set rotating speed value, not allowing the vehicle to downshift to the third gear.

5. The AMT upshift control method of claim 3, wherein, calculating a first minimum required torque for the engine to overcome the running resistance when the vehicle downshifts to the first gear, and obtaining a first fuel consumption value of the vehicle downshifted to the first gear from the universal table according to the first minimum required torque and the first theoretical output rotating speed; calculating a second minimum required torque for the engine to overcome the running resistance when the vehicle downshifts to the second gear, and obtaining a second fuel consumption value of the vehicle downshifted to the second gear from the universal table according to the second minimum required torque and the second theoretical output rotating speed; calculating a third minimum required torque for the engine to overcome the running resistance when the vehicle downshifts to the third gear, and obtaining a third fuel consumption value of the vehicle downshifted to the third gear from the universal table according to the third minimum required torque and the third theoretical output rotating speed; wherein the universal table is a table formed by required torque, theoretical output rotating speed and fuel consumption value.

6. The AMT upshift control method of claim 1, wherein, The specific steps of the second downshifting strategy include: determining whether the second theoretical output rotating speed is less than or equal to a second set rotating speed value; if the second theoretical output rotating speed is greater than the second set rotating speed value, determining whether the first theoretical output rotating speed is less than or equal to a first set rotating speed value; if the first theoretical output rotating speed is less than or equal to the first set rotating speed value, allowing the vehicle to downshift to the first gear; controlling the vehicle to downshift to the first gear; if the first theoretical output rotating speed is greater than the first set rotating speed value, not allowing the vehicle to downshift.

7. The AMT upshift control method of claim 6, wherein, if the second theoretical output rotating speed is less than or equal to the second set rotating speed value, allowing the vehicle to downshift to the second gear; determining whether the third theoretical output rotating speed of the engine after downshifting to the third gear is less than or equal to a third set rotating speed value; if the third theoretical output rotating speed is less than or equal to the third set rotating speed value, allowing the vehicle to downshift to the third gear; if the third theoretical output rotating speed is greater than the third set rotating speed value, not allowing the vehicle to downshift to the third gear; if both the vehicle is allowed to downshift to the second gear and the vehicle is allowed to downshift to the third gear, determining the final downshifting of the vehicle according to the minimum value of the fuel consumption value allowing the vehicle to downshift to the second gear and the fuel consumption value allowing the vehicle to downshift to the third gear.

8. The AMT upshift control method of claim 1, wherein, The specific steps of the third downshifting strategy include: determining whether the third theoretical output rotating speed is less than or equal to a third set rotating speed value; if the third theoretical output rotating speed is less than or equal to the third set rotating speed value, allowing the vehicle to downshift to the third gear; controlling the vehicle to downshift to the third gear; If the third theoretical output rotating speed is greater than a third set rotating speed value, it is judged whether the second theoretical output rotating speed is less than or equal to a second set rotating speed value; if the second theoretical output rotating speed is less than or equal to the second set rotating speed value, the vehicle is allowed to drop two gears; the vehicle is controlled to drop two gears; if the second theoretical output rotating speed is greater than the second set rotating speed value, it is judged whether the first theoretical output rotating speed is less than or equal to a first set rotating speed value; if the first theoretical output rotating speed is less than or equal to the first set rotating speed value, the vehicle is allowed to drop one gear; the vehicle is controlled to drop one gear; if the first theoretical output rotating speed is greater than the first set rotating speed value, the vehicle is not allowed to drop gears.

9. Vehicle, characterized in that The AMT up-hill gear shifting control method according to any one of claims 1-8, wherein the vehicle comprises the engine system.

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