A design method for shifting strategy of binary logic automatic transmission

Abstract

The present invention proposes a shift strategy design method for a binary logic automatic transmission (BLT). This method is used to determine the target gear for the current shift of a BLT, thereby improving the shift performance of the automatic transmission and, in turn, the power and economy of vehicles equipped with BLTs. Specifically, the method comprises: first, collecting the input shaft speed and throttle opening of the automatic transmission; when the collected input shaft speed is greater than a set upshift threshold, an upshift condition is triggered; when the input shaft speed is less than a downshift threshold, a downshift condition is triggered; after the upshift condition is triggered, the maximum target gear for upshifting is first calculated, and then the gear with the least components switched during the shift is selected between the current gear and the maximum target gear for upshifting as the current target gear; after the downshift condition is triggered, a preset throttle opening-shift speed table is queried based on the current throttle opening to determine the shift speed, and sequential downshifting is performed when the input shaft speed is less than the shift speed.

Description

Technical Field

[0001] The present invention relates to a transmission shift strategy design, in particular to a dual-state logic automatic transmission shift strategy design, and belongs to the technical field of transmission shift control. Background Art

[0002] The double internal meshing planetary gear mechanism is a new type of planetary gear mechanism that has appeared in recent years. The automatic transmission composed of this planetary gear mechanism is called a dual-state logic automatic transmission. This automatic transmission has the advantages of simple shifting process and multiple gears, which greatly improves the power, economy and comfort of vehicles equipped with this automatic transmission.

[0003] To improve vehicle transmission efficiency, automatic transmissions are adding more gears. However, due to space and size limitations, current automatic transmissions only offer 16 gears. Dual-state logic automatic transmissions utilize a novel gear mechanism, overcoming these limitations and enabling 32 gears (as disclosed in Application No. 201811444529.7, a 32-speed automatic planetary transmission). This significantly improves transmission efficiency. However, with more gears, the shift control method based on the transmission becomes more complex, increasing shift time and weakening shift response characteristics. Therefore, a shift strategy design method suitable for dual-state logic automatic transmissions is needed to improve shift quality. Summary of the Invention

[0004] In view of this, the present invention proposes a dual-state logic automatic transmission shift strategy design method for determining the target gear of the current shift of the dual-state logic automatic transmission, which can improve the automatic transmission shift performance and thereby improve the power and economy of vehicles equipped with the dual-state logic automatic transmission.

[0005] The technical solution of the present invention is: a design method for a shift strategy of a dual-state logic automatic transmission,

[0006] Step S1: collecting the input shaft speed and throttle opening of the automatic transmission;

[0007] Step S2: When the collected input shaft speed is greater than the set upshift threshold, an upshift condition is triggered; when the input shaft speed is less than the downshift threshold, a downshift condition is triggered;

[0008] Step S3: After the upshift condition is triggered, the maximum target gear for upshifting is first calculated, and then the gear with the least number of components switched during the shift is selected between the current gear and the maximum target gear for upshifting as the current target gear for upshifting;

[0009] After the downshift condition is triggered, the preset throttle opening-shift speed table is queried according to the current throttle opening to determine the shift speed. When the input shaft speed is less than the shift speed, a sequential downshift is performed, that is, the downshift target gear = the current gear - 1.

[0010] As a preferred embodiment of the present invention: in step S2, it is first determined whether the previous gear shift of the automatic transmission is completed, and the current gear shifting condition is triggered only after the previous gear shift is completed.

[0011] As a preferred embodiment of the present invention: in step S1, the target gear position of the previous gear shift and the current actual gear position of the automatic transmission are also collected;

[0012] When the target gear position of the previous gear shift is equal to the current actual gear position, the gear shift completion flag is set to 1, otherwise it is 0;

[0013] In step S2, when the collected input shaft speed is greater than the set upshift threshold and the shift completion flag is 1, the upshift condition is triggered; when the collected input shaft speed is less than the downshift threshold and the shift completion flag is 1, the downshift condition is triggered.

[0014] As a preferred embodiment of the present invention: Step S3: firstly calculate the input shaft speed change rate and the throttle opening change rate;

[0015] After triggering the upshift condition:

[0016] When the input shaft speed is greater than the preset forced upshift input shaft speed threshold, the transmission is forced to upshift sequentially;

[0017] When the input shaft speed is not greater than the forced upshift input shaft speed threshold, the upshift condition is determined based on the input shaft speed change rate and the throttle opening change rate:

[0018] When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 1 is used to determine the target gear;

[0019] When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, upshift condition 2 is used to determine the target gear;

[0020] When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 3 is used to determine the target gear;

[0021] When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, the gear will not be shifted up;

[0022] Among them: When using upshift condition 1, first use the following formula to calculate the target transmission ratio:

[0023] Target transmission ratio = (set input shaft speed / current input shaft speed) * current gear transmission ratio

[0024] Then, according to the target transmission ratio, the gear position-gear ratio-shift logic table of the automatic transmission is searched to obtain the maximum target gear position for upshifting corresponding to the target transmission ratio, and then the gear position with the least switching components between the current gear position and the maximum target gear position for upshifting is selected as the current target gear position;

[0025] When the target gear position is determined using upshift condition 2 and upshift condition 3, the target gear position = current gear position + 1.

[0026] As a preferred embodiment of the present invention: Step S3: firstly calculate the throttle opening change rate;

[0027] After the downshift condition is triggered, the shift speed is determined by querying the preset throttle opening-shift speed table based on the current throttle opening and the throttle opening change rate. Two different shift speeds are set in the throttle opening-shift speed table corresponding to the throttle opening value, namely shift speed A and shift speed B:

[0028] When the throttle opening change rate is less than or equal to the set throttle opening change rate threshold B, the shift speed is determined by looking up the shift speed A in the throttle opening-shift speed table. When the throttle opening change rate is greater than the set throttle opening change rate threshold B, the shift speed is determined by looking up the shift speed B in the throttle opening-shift speed table.

[0029] When the input shaft speed is less than the shift speed, sequential downshifting is performed, that is, the downshift target gear = current gear - 1.

[0030] Beneficial effects:

[0031] (1) The present invention provides a method for designing a shifting strategy for a binary logic automatic transmission. The method determines the target gear position of the current shift of the binary logic automatic transmission with the goal of minimizing clutch switching during the shifting process. This method can improve the shifting performance of the binary logic automatic transmission. The method is suitable for vehicles with automatic transmissions that have multiple gears and multiple components.

[0032] (2) In the present invention, before triggering the current gear shifting condition, it is first determined whether the previous gear shift of the transmission is completed to ensure the reliability of the gear shifting.

[0033] (3) In the present invention, after the upshift condition is triggered, the upshift condition is determined based on the input shaft speed change rate and the throttle opening change rate, which can improve the power and economy of the vehicle equipped with a dual-state logic automatic transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flowchart of the method for designing a shift strategy for a binary logic automatic transmission. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and preferred embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0036] This embodiment provides a method for designing a shift strategy for a binary logic automatic transmission. This method aims to minimize clutch switching during the shift process and optimizes the shift strategy of the binary logic automatic transmission disclosed in application number 201811444529.7 to determine the target gear position for the current shift of the binary logic automatic transmission. This method can improve the shift performance of the binary logic automatic transmission and is suitable for vehicles with automatic transmissions that have multiple gears and multiple shift elements.

[0037] like Figure 1 As shown, the specific steps of the dual-state logic automatic transmission shift strategy design method are:

[0038] Step S1: Signal acquisition:

[0039] Collect signals such as the input shaft speed, target gear position (the target gear position of the previous gear shift), actual gear position, and throttle opening of the dual-state logic automatic transmission;

[0040] Step S2: Determine the shifting condition:

[0041] Determine whether the previous gear shift is completed based on the target gear position and actual gear position signals collected in step S1. When the target gear position is equal to the actual gear position, the gear shift completion flag is set to 1, otherwise it is set to 0;

[0042] Based on the input shaft speed signal collected in step S1, it is determined whether the automatic transmission meets the upshift condition and the downshift condition. When the input shaft speed is greater than the set upshift threshold and the shift completion flag is 1, the upshift setting module is triggered; when the input shaft speed is less than the downshift threshold and the shift completion flag is 1, the downshift setting module is triggered; that is, the current gear shift can only be performed after the previous gear shift is completed.

[0043] Step S3: Determine the shift strategy:

[0044] Upshift strategy:

[0045] First, calculate the input shaft speed change rate ((input shaft speed at current moment - input shaft speed at last sampling moment) / sampling time) and the throttle opening change rate ((current throttle opening - throttle opening at last sampling moment) / sampling time);

[0046] When the upshift setting module is triggered in step S2, the upshift setting is performed by the upshift setting module:

[0047] The upshift setting module has a preset forced upshift input shaft speed threshold. When the input shaft speed is greater than the forced upshift input shaft speed threshold, the transmission is forced to upshift sequentially.

[0048] When the input shaft speed is not greater than the forced upshift input shaft speed threshold, the upshift condition is determined based on the input shaft speed change rate and the throttle opening change rate, specifically:

[0049] When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 1 is used to determine the target gear;

[0050] When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, upshift condition 2 is used to determine the target gear;

[0051] When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 3 is used to determine the target gear;

[0052] When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, the gear is not shifted up, that is, the current gear is kept unchanged.

[0053] Among them: When using upshift condition 1, first use the following formula to calculate the target transmission ratio:

[0054] Target transmission ratio = (set input shaft speed / current input shaft speed) * current gear transmission ratio

[0055] Then, according to the target transmission ratio, the table is looked up to find the maximum target gear for the current upshift. The specific example is as follows: set the input shaft speed to 1200r / min, assuming that the current input shaft speed is 1800r / min, and the current gear is 10th gear, then the target transmission ratio = (1200 / 1800)*5.4=3.6; query the gear-transmission ratio-shift logic table of the automatic transmission (i.e., Table 1 below) to obtain the maximum target gear corresponding to the transmission ratio, which is 14th gear (therefore, 11th gear to 14th gear can all be used as target gears, and 14th gear is the maximum target gear); then, among the 11th gear to 14th gear, the gear with the least switching components is selected as the target gear; in this example, since the upgrade from 10th gear to 11th gear requires the control of two couplings, the upgrade from 10th gear to 12th gear requires the control of one coupling, the upgrade from 10th gear to 13th gear requires the control of two couplings, and the upgrade from 10th gear to 14th gear requires the control of one coupling, so in this example, 14th gear is finally selected as the target gear.

[0056] When the calculated target transmission ratio is not the transmission ratio value in Table 1 below, the nearest gear that is larger than the calculated target transmission ratio is selected as the maximum target gear.

[0057] Table 1: Gear position, transmission ratio and shift logic table for automatic transmission

[0058]

[0059] Upshift conditions 2 and 3 adopt a sequential upshift strategy, that is, the target gear position = current gear position + 1.

[0060] Downshift strategy:

[0061] When the downshift setting module is triggered in step S2, the downshift setting is performed by the downshift setting module:

[0062] When downshifting, the downshift setting module queries the preset throttle opening-shift speed table (as shown in Table 2) based on the current throttle opening and the throttle opening change rate to determine the shift speed. In the throttle opening-shift speed table, two different shift speeds are set corresponding to the throttle opening value, namely shift speed A and shift speed B.

[0063] When the throttle opening change rate is less than or equal to the set throttle opening change rate threshold value B, the throttle opening-shift tachometer is checked and the shift speed is determined by the shift speed A. When the throttle opening change rate is greater than the set throttle opening change rate threshold value B, the throttle opening-shift tachometer is checked and the shift speed is determined by the shift speed B.

[0064] Table 2: Throttle opening-shift speed table

[0065]

[0066] When the input shaft speed is less than the shift speed, sequential downshifting is performed, that is, the downshift target gear = current gear - 1.

[0067] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for designing a shift strategy for a binary logic automatic transmission, characterized by: Step S1: collecting the input shaft speed and throttle opening of the automatic transmission; Step S2: When the collected input shaft speed is greater than the set upshift threshold, an upshift condition is triggered; when the input shaft speed is less than the downshift threshold, a downshift condition is triggered; Step S3: After the upshift condition is triggered, the maximum target gear for upshifting is first calculated, and then the gear with the least number of components switched during the shift is selected between the current gear and the maximum target gear for upshifting as the current target gear for upshifting; After the downshift condition is triggered, the preset throttle opening-shift speed table is queried according to the current throttle opening to determine the shift speed. When the input shaft speed is less than the shift speed, a sequential downshift is performed; Step S3: firstly calculate the input shaft speed change rate and the throttle opening change rate; After triggering the upshift condition: When the input shaft speed is greater than the preset forced upshift input shaft speed threshold, forced upshift is performed sequentially; When the input shaft speed is not greater than the forced upshift input shaft speed threshold, the upshift condition is determined based on the input shaft speed change rate and the throttle opening change rate: When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 1 is used to determine the target gear; When the input shaft speed change rate is greater than or equal to the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, upshift condition 2 is used to determine the target gear; When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is less than the set throttle opening change rate threshold A, upshift condition 3 is used to determine the target gear; When the input shaft speed change rate is less than the set speed change rate threshold and the throttle opening change rate is greater than or equal to the set throttle opening change rate threshold A, the gear will not be shifted up; Among them: When using upshift condition 1, first use the following formula to calculate the target transmission ratio: Target transmission ratio = (set input shaft speed / current input shaft speed) * current gear transmission ratio Then, according to the target transmission ratio, the gear position-gear ratio-shift logic table of the automatic transmission is searched to obtain the maximum target gear position for upshifting corresponding to the target transmission ratio, and then the gear position with the least switching components between the current gear position and the maximum target gear position for upshifting is selected as the current target gear position; When the target gear is determined using upshift condition 2 and upshift condition 3, the target gear = current gear + 1.

2. The method for designing a shift strategy for a binary logic automatic transmission according to claim 1, characterized in that: In step S2, it is first determined whether the previous gear shift of the automatic transmission is completed. Only after the previous gear shift is completed, the current gear shifting condition is triggered.

3. The method for designing a shift strategy for a binary logic automatic transmission according to claim 2, wherein: In step S1, the target gear position of the previous gear shift and the current actual gear position of the automatic transmission are also collected; When the target gear position of the previous gear shift is equal to the current actual gear position, the gear shift completion flag is set to 1, otherwise it is 0; In step S2, when the collected input shaft speed is greater than the set upshift threshold and the shift completion flag is 1, the upshift condition is triggered; when the collected input shaft speed is less than the downshift threshold and the shift completion flag is 1, the downshift condition is triggered.

4. The method for designing a shift strategy for a binary logic automatic transmission according to any one of claims 1 to 3, characterized in that: Step S3: firstly calculate the throttle opening change rate; After the downshift condition is triggered, the shift speed is determined by querying the preset throttle opening-shift speed table based on the current throttle opening and the throttle opening change rate. Two different shift speeds are set in the throttle opening-shift speed table corresponding to the throttle opening value, namely shift speed A and shift speed B: When the throttle opening change rate is less than or equal to the set throttle opening change rate threshold B, the shift speed is determined by looking up the shift speed A in the throttle opening-shift speed table. When the throttle opening change rate is greater than the set throttle opening change rate threshold B, the shift speed is determined by looking up the shift speed B in the throttle opening-shift speed table. Sequential downshifting occurs when the input shaft speed is less than the shift speed.

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