車輛工程外文翻譯-地面車輛自動變速器的換擋節(jié)能研究【中文3880字】【PDF+中文WORD】
車輛工程外文翻譯-地面車輛自動變速器的換擋節(jié)能研究【中文3880字】【PDF+中文WORD】,中文3880字,PDF+中文WORD,車輛,工程,外文,翻譯,地面,自動變速器,換擋,節(jié)能,研究,中文,3880,PDF,WORD
地面車輛自動變速器的換擋節(jié)能研究
龔捷,趙丁選,陳鷹,陳寧
摘要:為了改善地面車輛的效率,通過對車輛動力傳動系統(tǒng)的液力變矩器和傳輸功能的研究,提出了地面車輛自動變速器的換擋規(guī)律。這種轉(zhuǎn)變計劃可以保持轉(zhuǎn)矩變換器在高效率范圍內(nèi)的所有工作條件下工作,除了當(dāng)傳輸工作在左側(cè)最低轉(zhuǎn)變時和在右側(cè)最高轉(zhuǎn)變時的低效率范圍內(nèi)。對換擋質(zhì)量的關(guān)鍵因素進行了分析。自動反式。對自動變速器試驗臺采用這種轉(zhuǎn)變的時間表進行了臺架試驗的任務(wù),試驗結(jié)果表明,換擋規(guī)律是正確的,這種轉(zhuǎn)變質(zhì)量可控。
關(guān)鍵詞:地面車輛,液力傳動,自動變速器,換擋,節(jié)約能源,換擋品質(zhì)
文獻標(biāo)識碼:A 中圖分類號:u270.1
引言
汽車自動變速技術(shù)廣泛應(yīng)用于地面車輛,來提高生產(chǎn)率和降低勞動強度。然而,在低速、重負荷和負荷急劇變化等各種操作條件的地面車輛的性能,與正常操作的汽車非常不同。因此,不能采用地面車輛鎖定離合器的方法用于汽車液力變矩器解決在低效率的工作范圍(龔,2002)。為了使能源的合理利用。根據(jù)實際的負載和換擋規(guī)律的研究,以決定轉(zhuǎn)變可能在高效率范圍內(nèi)工作的扭矩轉(zhuǎn)換器。這是轉(zhuǎn)變的決策問題。
我們知道,車輛發(fā)動機與液力變矩器是復(fù)雜的非線性系統(tǒng),很難控制。模糊控制結(jié)合人類經(jīng)驗算法能夠處理非線性系統(tǒng),不需要正式分析結(jié)構(gòu)的應(yīng)用能力。在過去的十年中,大量的工作人員對自動化變速器的控制系統(tǒng)進行了模糊控制的探索性工作(山口等人,1993;坂口,1993;沈,1997)。與傳統(tǒng)的控制相比,模糊控制是一種滿意而不是最優(yōu)的控制。本研究關(guān)注的是液力變矩器和變速器在車輛傳動系的控制作用,確定變矩器保持在高效區(qū)工作的一個新的換擋變速。
換擋循環(huán)
轉(zhuǎn)變調(diào)節(jié)移矩(自動變速器的各種變化)的控制參數(shù)。是自動變速器開發(fā)的關(guān)鍵技術(shù);并直接影響車輛的經(jīng)濟性能和動力性能。
這部分內(nèi)容如下:首先,給出高效率范圍和低效率范圍的定義。而后,對為什么變矩器在低效率范圍內(nèi)工作的原因進行了討論。最后,提出了解決問題的方法。
效率高范圍和低效率的范圍定義
為了評估液力變矩器的經(jīng)濟性能,變矩器的效率不應(yīng)小于理想值( = 75%使用在工程機械, = 80%的汽車通常)。YJ355的液力變矩器的主要特點是顯示在圖1(趙 et a1。,2001)。有兩點滿足= 。全工況變矩器的條件分為兩個點,即三個地區(qū),效率低的范圍,低比轉(zhuǎn)速定位,高效率范圍和低效率范圍在高速率的定位。當(dāng)轉(zhuǎn)矩變換器工作在效率低的范圍內(nèi),工況點位于低或高速率,換擋規(guī)律必須控制變速器的換擋,使變矩器在高效區(qū)工作。
圖1. YJ355液力變矩器的主要特點
液力變矩器的低效率范圍內(nèi)工作的原因
根據(jù)不同的操作條件,液力變矩器可乘以轉(zhuǎn)矩。對于裝有液力變矩器的地面車輛,液力變矩器的工況點從高的效率范圍內(nèi)移到低效率范圍,定位在低速率作為車輛的持續(xù)性增加。反之,變矩器的工況點從高的效率范圍移到低效率范圍,定位在高速率作為車輛的持續(xù)性降低。它可以被稱為自動控制系統(tǒng)。因此,換擋規(guī)律的計算公式如下。
轉(zhuǎn)換理論
換擋規(guī)律是控制發(fā)動機和液力變矩器的一套共同工作點,使液力變矩器的效率不小于理想值;換句話說,滿足條件的點 =作為換擋點。換擋決定自動變速控制系統(tǒng)計算傳動比,控制液力變矩器在的范圍內(nèi)工作。
地面車輛模型如圖2所示(龔和趙,2001a;2001b)。
圖.2 車輛的模型
首先,我們考慮的情況下,變矩器低速比的工作定位在低效率的范圍。據(jù)推測,在圖1表示的兩個工況點滿足在低效率范圍內(nèi)定位在低速比和換擋點的條件 = r/,、分別代表兩個點的轉(zhuǎn)矩。
假設(shè)它是傳動齒輪比。動工況點在效率低的范圍內(nèi)的效率高,傳動是用來增加轉(zhuǎn)矩。然后是
(1)
液力變矩器在低效率的范圍定位在高速率工作時,方程(1)中得到的相同的方式。不同的是,是在高速率的換擋點對應(yīng)的輸出轉(zhuǎn)矩。
以上兩種情況綜合起來。由于在車輛驅(qū)動系統(tǒng)的傳輸函數(shù)是通過變速調(diào)節(jié)驅(qū)動系統(tǒng)的輸出轉(zhuǎn)矩,上面得到的是多個(或分?jǐn)?shù))的變速器輸出轉(zhuǎn)矩在接下來的時刻。然而,一個連續(xù)的換擋過程中,變速器已經(jīng)在一定的轉(zhuǎn)移,即,變速器輸出扭矩被放大到一小部分在目前的大小是傳動裝置的傳動比。因此,多(或分?jǐn)?shù))的變速器輸出轉(zhuǎn)矩在下一刻,必須增加(或減少)由一個因子一次。換句話說,在下一個時刻齒輪比必須增加(或減少)的一個因素,它在現(xiàn)有的齒輪比的基礎(chǔ)上,這是
(2)
其中是在下一個時刻齒輪傳動比,是目前齒輪傳動比。
從方程:(1)和(2),該換擋規(guī)律的計算公式如下:
(3)
雖然傳輸?shù)睦硐雮鲃颖冗B續(xù)值。實際的齒輪比的傳輸提供的是離散的有限值。在實際應(yīng)用中,齒輪比的選擇根據(jù)是否變矩器的工況點位于低速率的地區(qū)或高一。的條件下,對液力變矩器工況點位于低速率最低的區(qū)域轉(zhuǎn)移時選用計算傳動比大于傳輸?shù)淖畲髠鲃颖雀蟮凝X輪比。否則會選擇當(dāng)計算傳動比傳動的傳動比之間的兩個實際的情況。液力變矩器的工作工況點位于高速率下的地區(qū),最高的移位時選用計算傳動比小于最小傳動比的傳動小齒輪比。 否則,小齒輪比將選擇當(dāng)計算傳動比傳動的傳動比之間的兩個實際。
現(xiàn)在。舉例說明如何使用它。假設(shè)4班制傳輸,i4 I 0.4
The ground vehicle model is shown in Fig.2 (Gong and Zhao, 2001a; 2001b).
First, we consider the case of the torque conv-
[10 0.2
o l 。V l o
0.2 0.4 0.6 0.8 1.0
Speed ratio i
Fig.I YJ355 Torque converter primary characteristics Fig.2 Model of vehicle
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880 Gong et al.I J Zhejiang L’niv SCI 2004 5(刀·878氣883
erter working in the low efficiency range locating in the low speed ratio. It is supposed that the two points in Fig. I represent the working condition
l
i _ ;
Inexl ’t pres町11 咱句
£1c lim
(3)
point in the low efficiency range locating in the low speed ratio and the shift point meeting the condition of 1J1c = 1J1c min, respectively, and Tic, Tic lim represent the two points' torque, respectively.
Suppose that the transmission gear ratio is i1. To move the working condition point to the high efficiency range from the low efficiency range, the transmission is used to increase the torque. Then there is
‘、.,
.
且
,aE、、
i, 兀 I T.c1 m
When the torque converter works in the low effi- ciency range locating in the high speed ratio, Eq.( 1) is obtained in the same way, where the difference is that Tic lim is the output torque coηesponding to the shift point in the high speed ratio.
The above two situations are considered to- gether. Since the function of the transmission in the vehicular drive system is to adjust the output torque of the drive system by gear shift, the above obtained i1 is the multiple (or fraction) of the transmission output torque at the next moment. However, during a continuous shift, the transmission is already in a certain shift, that is, the transmission output torque has been magnified to a fraction at the present moment and the magnitude is the gear ratio of the transmission . Therefore, the multiple (or fraction) of the transmission output torque at the next mo- ment must be increased (or decreased) by a factor i1 again. In other words, the gear ratio at the next moment must be increased (or decreased) by a factor i1 on the basis of the present gear ratio, that is
Although the ideal gear ratios of the trans- mission are continuous values, the actual gear ra- tios of the transmission supplied are discrete finite values. In practical applications, the gear ratio is chosen according to whether the working condition point of the torque converter locates in the low speed ratio region or in the high one. Under the condition that the working condition point of the torque converter locates in the low speed ratio re- gion, the lowest shift is chosen when the calculated gear ratio is larger than the maximum gear ratio of the transmission . Otherwise the bigger gear ratio will be chosen when the calculated gear ratio is between the two actual gear ratios of the transmis- sion. Under the condition that the working condi- tion point of the torque conve口er locates in the high-speed ratio region, the highest shift is chosen when the calculated gear ratio is smaller than the minimum gear ratio of the transmission. Otherwise the smaller gear ratio will be chosen when the calculated gear ratio is between the two actual gear ratios of the transmission .
Now, an example is taken to show how it is used. Suppose that a transmission with 4 shifts, i4< i3 < i2 < i1, where i,, is gear ratio, n is shift, and
= 1,2,3,4. The shift is chosen as shown in Table 1.
腳1ethod to prevent shift cycling
As discussed before, the upshift point and the downshift point are the same in the above shift
schedule. In order to prevent the transmission "hunting” in use, a method is adopted to distinguish
Table 1 Shi“ choosing measure
l Inexl = lIpresenl lt (2)
where i1nex1 is the transmission gear ratio at the next moment, i1 present is the transmission gear ratio at present.
From Eqs.( 1) and (2), the shift schedule for- mula is as follows:
i, nexr < i4
/4 < i, nex 1 < i3
13 < 11 ne< I < i2
i2 < iInexl < iI
i, nex 1 > i1
Shift when the Shift when the working point is working point is in i n low speed ratio high speed ratio
4
A『 句‘d
3
叮’h
2
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Gong et al. 1 J Zh吃;iang U11ii· SCI 2004 5(刀·878-883 881
the normal from the frequent gear that changes shi白.
Firstly, since the shift frequency of the ground vehicle is nearly a thousand times per hour (Wang et al., 2000), the minimum time interval from one shift to the next is chosen to be 2 seconds. Suppose
that the time of the data acquisition is t (m時,the
frequency of the shift decision between two shifts is 2000/t . Therefore, when the frequency of the up- shift (or downshift) is half of the shift decision
times, it is a frequent gear changes shift. When the times of the upshi白(or downshift) are the same as
the shift decision times, it is a normal gear changes shift.
The method not only adapts to the above shift schedule, but also acts as a general method for all shift schedules to avoid shift cycling.
SHIFT QUALITY
The gear shift is completed by controlling clutch or brake to engage or disengage. As shift quality is closely linked to whether a shift schedule can be applied to the actual vehicle, it is necessary to discuss the deliberated index and the main fac- tors affecting shift quality, in order to provide a theoretical basis for improving shift quality.
At present, jerk is used as the deliberated index of shift smoothness. Jerk is defined as the change of the longitudinal acceleration of the automobile. Its mathematical expression is (Lei et al., 1999)
unchanged during a shi白,lw is the moment of in- ertia relating to the part of the transmission output sha白.
The above formula shows that the effective method of decreasing jerk is to control the effect of torque change on the transmission output shaft, that is, to make the torque change minimum .
BENCH-TEST
In order to verify the shift schedule, an auto-
matic transmission test experiment was made on an automatic transmission ’s test-bed.
Componen t of automatic transmission ’s test-bed The components and control method of the automatic transmission ’stest-bed is shown in Fig.3.
It can be seen that the automatic transmission ’s
test-bed consists of an engine, a torque converter, a transmission, a speed increaser, and an electric eddy current dynamometer. The engine is a power supply. The electric eddy cuπent dynamometer is a power dissipation device used for loading for the drivetrain by adjusting winding cuπent to change the brake load. The speed increaser is used for matching the rotational speed for the electric eddy current dynamometer. During the test, the speed and torque of the engine and the torque converter were acquired and processed by a computer. The computer control actuator’s electromagnetic valve
Electric eddy current dyna- mometer controller
(4)
iof w dt i0lw dt
where ),α,v are the jerk , acceleration and speed of the vehicle, respectively , t is time, rr is the wheel radius, i0 is the gear ratio between the transmission output shaft and the driving wheel, woT, ToT are the angular velocity and torque of the transmission
output shaft, respectively , Tw is the resistance Fig.3 Schematic diagram for the automatic gear sh惱’s moment acting on the wheel, and supposed to be test-bed
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882 Gong et al. I J Zh吃;iang l.iniν SCI 2004 5(7):878-883
opened or closed to implement shift according to the shift schedule.
Experimental results of shift schedule
氣d
l
F3
1
u
(法)PEzguE兇
The torque converter efficiency was controlled to be over 75% in the test. The time interval of the data acquisition was set to be 200 ms. The ex- perimental results obtained by connecting the points of the data acquisition are shown in Fig.4. The
course of downshift corresponded with that of in- creasing load in Fig.4b. The course of upshi白cor- responded with that of decreasing load. The points of efficiency less than 75% in Fig.4a were those determined by shift decision. The experimental results proved that the shift schedule saving energy could make torque converter work in the high ef- ficiency range by gear shift according to the actual load acting on the drivetrain.
句、“
句,-
62出 口 。叫目的g-
ESH
4
400
i350
邑 300
氈,
否。250
C
-;; 200
:-e I SO
← 100
100
200
300
400
500
氣d 5
氣,
1 o· l
α
rL
Time t (s)
(a)
100 200 300
Time t (s)
(b)
400
500
Experimental results of shift quality
The measured results of the torque converter output torque are shown in Fig.4c.
I) On the test site, we felt that the impact and vibration of the downshift were stronger than that of the upshift. The reason for this, as explained by Eq.(4) and Fig.4c, is that the torque change of the downshift is bigger than that of the upshift.
2) There is a trough in Fig.4c, coπesponding to each shift point. This phenomenon indicates oc- cuπence of power inteπuptions during gear shi位,
3) To study the controllability condition of shift quality, the thirteen shift points in the test were carefully analysed. To expound the course of gear shift, the experimental data of three gear shift courses were extracted from the experimental re- cord, and listed in Table 2. In order to easily de- scribe the course of the gear shift. The measured point, after shift instruction is sent out, is called a shift point and marked as point l . The point before the shift point is marked as point 0. The point after the shift point is marked as point 2, the rest can be deduced by analogy. The torque converter output torque of each group has the following changing rule:the torque converter output torque of point 1 is less than that of point 0, the torque converter output torque of point 2 reduces more than that of point 1, the torque converter output torque of point 3 in- creases more than that of point 2, the torque con- verter output torque of point 4 is the biggest among
those of point 2, point 3 and point 5.
nυ
nv
l
200 300 400
Time t (s)
(c)
500
The course of the gear shift indicates that the clutch of the original shift began to slip at point l .
The clutch of the original shift disengaged and the
Fig.4 Experimental results of the automatic gear shift’s
test-bed (a) Efficiency change; (b) Transmission shift change; (c) Turbine torque change
clutch of the new shift did not engage at point 2. At this moment, power interruptions occurred. The
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Gong et al.I J Zhejiang Univ SCI 2004 5(7):878-883 883
clutch of the new shift began to slip at point 3 and engaged at point 4.
Conclusion
From the above experimental results, we can
conclude that:
SUMMARY
In order to solve the problem of the low torque converter efficiency in the automatic transmission of the ground vehicle under heavy load, a new shift schedule saving energy is proposed for the auto-
1) The shift schedule saving energy
can
matic transmission of the ground vehicle. Experi-
maintain the torque converter working in the range of an ideal value under all the working conditions except the following two cases, one is the low ef- ficiency range on the left when the transmission works in the lowest shift, and the other is the low efficiency range on the right when the transmissi(?n works in the highest shift.
2) Random load was imposed on the drivetrain during the test. Although the above shift schedule
saving energy was obtained by the studying torque converter’s primary characteristic, the experimen- tal results showed that the shift schedule saving energy is coηect while the torque converter is
working under conditions of the kinetic characteristic.
3) In order to reduce the impact of the gear shift in the test, it could be known that the clutch of the new shift should be engaged 200 ms earlier than that of the original shift to be disengaged. Therefore, shift quality can be improved by timing control.
Table 2 Experimental data of three shift courses
Torque converter output
ment on the automatic transmission bench-test adopting this shift schedule was made on the
automatic transmission ’s test-bed. The experi-
mental results showed that the shift schedule was coηect and that shift quality was controllable. The above research results provide reliable basis for application to ground vehicle and improving shift quality.
References
Gong, J., Zhao, D.X., 200 la. Study on shift schedule and simulation of automatic transmission . Chinese Journal of Mechanical Engineering , 14:250-253 .
Gong,工,Zhao, D.X., 2001b. Study on shift schedule and
auto-controlling simulation of automatic transmission . Journal of 刀’an Jiaotong Universi紗,35:930-934 (in Chinese).
Gong, J., 2002. Study on Shift Schedule of Automatic Transmission for High Efficiency. Ph.D thesis, Jilin University, China (in Chinese).
Lei, Y.L., Ge, A.L., Qin, G.H., 1999. Testing study of improving shift quality of automated mechan
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