動(dòng)力換擋系統(tǒng)和換擋策略標(biāo)定

楊一凡

采埃孚（中國(guó)）投資有限公司

ZF （China）Investment Co.，Ltd.

上海工程中心

簡(jiǎn)介：

自動(dòng)變速器中的電子及液壓元件代替了傳統(tǒng)手動(dòng)擋車輛中駕駛員將變速箱從一檔切換到另外一檔的工作?？刂栖浖械膮?shù)須做出相應(yīng)的調(diào)整，以實(shí)現(xiàn)平順的換擋，對(duì)于追求舒適性的換擋要求來(lái)說，最完美的換擋是讓駕駛員以及乘客無(wú)法察覺到換擋過程，另外適宜的換擋策略對(duì)于車輛的駕駛性也是非常重要的。自動(dòng)變速器標(biāo)定工程師的任務(wù)就是調(diào)整控制軟件中的參數(shù)，以達(dá)到車輛的最佳表現(xiàn)。

自動(dòng)變速器標(biāo)定

自動(dòng)變速器的標(biāo)定是指調(diào)整變速器控制軟件內(nèi)的控制參數(shù)，通過調(diào)整這些參數(shù)，用以實(shí)現(xiàn)在各個(gè)駕駛工況以及各種環(huán)境條件下對(duì)車輛換擋表現(xiàn)的良好控制。

在應(yīng)用開發(fā)過程中，自動(dòng)變速器在實(shí)車上的標(biāo)定是非常重要的，同時(shí)也占用了最長(zhǎng)的開發(fā)周期。所有的參數(shù)都必須根據(jù)特定的發(fā)動(dòng)機(jī)，車重，主減速比，液力變矩器特性，駕駛性要求等進(jìn)行調(diào)整。

對(duì)于ZF自動(dòng)變速箱的標(biāo)定來(lái)說，換擋過程控制（HPSYS）以及換擋策略控制（ASIS）是主要的標(biāo)定對(duì)象。

換擋過程控制的標(biāo)定

ZF的6HP變速器內(nèi)通過一個(gè)單行星齒輪組，一個(gè)雙行星排和五組換擋元件（既離合器以及制動(dòng)器）將來(lái)自發(fā)動(dòng)機(jī)的輸出扭矩以不同的組合形式傳遞到變速器輸出端從而驅(qū)動(dòng)動(dòng)力總成。換擋過程控制的任務(wù)是以電子液壓系統(tǒng)控制換檔元件從而驅(qū)動(dòng)相應(yīng)的齒輪組，擋位的切換是通過離合器或制動(dòng)器的打開與閉合而從機(jī)械上實(shí)現(xiàn)的。

Introduction

In an automatic transmission，electronic and hydraulic components have to take over the tasks of a driver to shift from one gear to another.In order to have a smooth transition in shifting from one gear to another，parameters in the control software have to be adjusted accordingly，so that best of all，the driver and the passengers in the car do not even recognize this shifting process.In addition，it is necessary that a proper shifting strategy has to be implemented.It is the task of a calibration engineer to adjust the parameters in the control software to achieve an optimum performance.

Definition of automatic transmission calibration

Automatic transmission calibration is adjusting parameters of functions in the transmission control software，which are not fixed in their values，to make the control suitable for a vehicle to perform well in all driving and environments conditions.

The automatic transmission calibration in prototype vehicles is a very important phase during application development，and it also lasts the longest.All the parameters must be properly adjusted for the specific engine，vehicle mass，final drive ratio，torque converter characteristics，requirements of drivability and etc.

For the calibration of an automatic transmission in ZF，the shift process control （named HPSYS）and the shift strategy control （named ASIS）are mainly calibrated.

圖1 三檔的動(dòng)力傳遞Fig.1 Power flow of 3rd gear

例如在三檔，液力變矩器渦輪驅(qū)動(dòng)前部齒圈，單行星齒輪組以及離合器E的外鼓。

前部齒圈1驅(qū)動(dòng)行星輪，行星輪圍繞一號(hào)太陽(yáng)輪旋轉(zhuǎn)，由此便驅(qū)動(dòng)了一號(hào)行星支架，同時(shí)驅(qū)動(dòng)了離合器A的外鼓和離合器B的內(nèi)鼓通過離合器A的結(jié)合，在雙行星排內(nèi)的三號(hào)太陽(yáng)輪被驅(qū)動(dòng)，從而帶動(dòng)短行星組。

二號(hào)太陽(yáng)輪被結(jié)合的離合器B所驅(qū)動(dòng)，由于長(zhǎng)行星齒輪組此時(shí)與短行星齒輪組相嚙合，不能圍繞二號(hào)太陽(yáng)輪相對(duì)自轉(zhuǎn)并驅(qū)動(dòng)了鎖死的雙行星排行

Calibration of the Hydraulic Planet Gear System（HPSYS）

ZF 6HP transmissions have one single planetary gear set，one double planetary gear set and 5 shift elements（clutches and brakes），which transfer the torque from engine output to power train with different combinations.Task of HPSYS is the controlling of shift elements by electronic－h(huán)ydraulic system，gear shifting is mechanically realized via clutches engaging and disengaging.

圖2 四檔的動(dòng)力傳遞Fig.2 Power flow of 4th gear

圖3 典型的三四動(dòng)力升檔Fig.3 Typical graph for a power up shifting from 3rd to 4th gear

對(duì)于該三四的動(dòng)力升檔來(lái)說，換擋指令是由換擋策略控制軟件根據(jù)當(dāng)前的油門開度以及變速器輸出端轉(zhuǎn)速共同決定并且釋放的。一旦換擋過程控制軟件接受該換擋指令，離合器B將會(huì)通過降低油壓而打開；同時(shí)離合器E將通過充油模型增加油壓而結(jié)合。當(dāng)離合器B的完全打開時(shí)，渦輪轉(zhuǎn)速和發(fā)動(dòng)機(jī)轉(zhuǎn)速應(yīng)該開始被離合器E的結(jié)合而拉向同步轉(zhuǎn)速。在動(dòng)力換擋過程中，可標(biāo)定的發(fā)動(dòng)機(jī)降扭要求將通過總線通訊發(fā)給發(fā)動(dòng)機(jī)控制模塊，要求發(fā)動(dòng)機(jī)此時(shí)減少一定的扭矩輸出。通過適當(dāng)?shù)陌l(fā)動(dòng)機(jī)降扭以及壓力標(biāo)定，變速器會(huì)把渦輪轉(zhuǎn)速拉到同星架，其轉(zhuǎn)動(dòng)方向與發(fā)動(dòng)機(jī)方向相同。

在四檔中，離合器A和E的結(jié)合實(shí)現(xiàn)了不同的速比。

對(duì)于三四的動(dòng)力升檔，要求結(jié)合的離合器由A和B切換到離合器A和E，也就是說需要離合器A保持結(jié)合，在結(jié)合離合器E的同時(shí)松開離合器B.

換擋過程控制標(biāo)定需要標(biāo)定工程師通過油壓的建立與釋放控制換擋的過程。標(biāo)定時(shí)需要駕駛車輛同時(shí)監(jiān)控系統(tǒng)內(nèi)的變量，例如發(fā)動(dòng)機(jī)轉(zhuǎn)速與扭矩，變速箱離合器油壓等等。例如圖三中所示的曲線。步轉(zhuǎn)速并完成換擋。

換擋時(shí)間（包括反應(yīng)時(shí)間和滑摩時(shí)間）必須控制在一定的范圍內(nèi)，從而兼顧換擋舒適性與避免離合器負(fù)載過大而異常的磨損。換擋舒適性可以通過輸出軸轉(zhuǎn)速的變化率進(jìn)行評(píng)估。

在匹配標(biāo)定過程需要避免出現(xiàn)以下的情況，因?yàn)榇祟惽闆r降低了換擋的舒適性或增加了離合器的負(fù)荷而產(chǎn)生磨損。

圖4 動(dòng)力升檔三四中，離合器B過早分離Fig.4 Power up shifting from 3rd to 4th gear with clutch B disengaged too fast

圖5 動(dòng)力升檔三四中，增加離合器E的換擋壓力Fig.5 Power up shifting from 3rd to 4th gear with increased shifting pressure to clutch E

For example，in the 3rdgear，the turbine drives the ring gear of the front，the single planetary gear set and the outer plate carrier of clutch E.Ring gear 1 drives the planetary gears，which roll round fixed sun wheel 1.This drives the planetary gear spider 1and at the same time the outer plate carrier A and the inner plate carrier of clutch B.with engaging of clutch A.The sun wheel 3in the double planetary gear set is driven；this meshes with the short planetary gears.Sun wheel 2is driven via engaged clutch B.The long planetary gears，which are in engagement with short ones，cannot roll round fixed sun wheel 2and drive the blocked double planetary gear carrier in the direction of engine rotation.

Similarly in the 4thgear，a different ratio is realized via the engagement of A and E.

A power up shifting from 3rdto 4thgear requires the engaged clutches from A and B switch to A and E，meaning the clutch A stays engaged and the clutch E need to be engaged，while the clutch B is disengaging.HPSYS calibration allows the calibration engineer to control how the shifting process from one gear into the next is performed.The calibration is done by driving the vehicle and monitoring different system parameters，such as engine speed and torque，transmission clutch pressure etc.An example for a typical simplified display is shown in Fig.3.

For the power up shifting from 3rdto 4thgear，a shifting command is released by the ASIS software dependent upon current accelerator pedal and output shaft speed.Once the HPSYS software accepts the shifting command，the shifting element B will be disengaged by decreasing oil pressure；meanwhile shifting element E will be engaged by increasing oil pressure.The torque will be transferred by an overlapping process from clutch B to clutch E.When clutch B is totally disengaged，the turbine speed and engine speed should be able to pull down to synchronous speed by engaging of clutch E.A calibrated torque intervention value will be sent to the engine control module to request an engine torque reduction at the same time.With proper engine torque decreasing and pressure of clutch E，the automatic transmission pulls down turbine speed to synchronous speed and finishes the shifting.

Shifting timing（reaction time and slipping time）must be within a certain range to achieve shift comfort and keep the clutches from wearing.Shift comfort can be judged from oscillations of output shaft.

The following examples show settings that should be avoided，as they are decreasing shifting comfort or increasing clutch wear：

圖6 動(dòng)力升檔三四中減少發(fā)動(dòng)機(jī)降扭請(qǐng)求Fig.6 Power up shifting from 3rd to 4th gear with decreasing torque intervention

標(biāo)定工程師根據(jù)采集到的數(shù)據(jù)曲線調(diào)整相應(yīng)的變量并重復(fù)這個(gè)過程，直到達(dá)到理想的換擋表現(xiàn)。

以下是換擋過程控制標(biāo)定中主要比配的項(xiàng)目。

以上所有功能會(huì)在不同溫度下進(jìn)行標(biāo)定及驗(yàn)證

換擋策略標(biāo)定（ASIS）

換檔過程的標(biāo)定決定著如何實(shí)現(xiàn)平滑的擋位切換，而換檔策略決定了應(yīng)該在什么時(shí)機(jī)實(shí)現(xiàn)擋位切換。換檔策略通常由客戶（整車廠）所定義，使用運(yùn)動(dòng)型的激進(jìn)換檔曲線，舒適型的換檔曲線或者是經(jīng)濟(jì)型的換檔曲線取決于車型的定位基本的換檔曲線是由當(dāng)前油門踏板開度和變速器輸出軸轉(zhuǎn)速確定的。例如下圖圖七

圖7 換擋曲線Fig.7 ASIS shift map

According to the observed curves，the calibration engineer adjusts parameters and monitors again the values.This is done iteratively，until the desired performance is achieved.

In the HPSYS calibration，mainly the following functions will be calibrated.

All the functions above are calibrated and verified at different temperatures

Calibration of Adaptive Shifting Strategy（ASIS）

While calibration of the HPSYS deals with how the change from one gear to the next is performed smoothly，the shifting strategy decides in general when the shifting process from one gear to the next is performed.In general the target for this is requested by the customer，who for example prefers a sportier，a more comfortable or an economical behavior.

A basic shift map is a map of shifting proposal which depends on the current accelerator pedal value and the output shaft speed.An example is shown in fig.7.

Fig.7 shows a typical basic shift map.The xaxis presents the output shaft speed/velocity of the vehicle；the y－axis presents the accelerator pedal value from 0to 100%.The solid lines are the up shifting lines；When the driving point（related to x and y）goes cross an up shifting line from left to right or from up to down or the mixture of these two directions，the shift map will release an up shifting command accordingly.For example，in case 1launching from stand still in 1st gear with 38%throttle，once the output shaft speed reaches 500rpm，1－2up shifting line is crossed，and 1－2up shifting will be proposed.

The dashed lines are the down shifting lines.When the driving point goes cross a down shifting line from the right to left or from down to up or the mixture of these two directions，the shift map will release a down shifting command accordingly.For example，in case 2driving with130kmh with 30%of accelerator pedal constantly，once the accelerator pedal is pressed up to 93%，a 6－5down shifting will be proposed.

The shift map is of significant importance for the ASIS calibration and therefore the comfort and drivability.This basic ASIS shift map is used for general driving conditions.Nevertheless，if certain special driving situations are detected，gear proposals from the shift map will be limited to release，earlier released etc.To do this，the calibration engineer calibrates special functions for improved dynamic drivability，some examples are the follow－

圖七中展示了基本的換擋曲線，二維坐標(biāo)的X軸為變速器輸出軸轉(zhuǎn)速（可換算為車速）；Y軸為加速踏板油門開度，范圍為0至100%。實(shí)線為升檔曲線；當(dāng)由車速與油門開度共同決定的工況點(diǎn)從左到右或自上到下或以以上兩種方向的組合穿過升檔曲線，換擋曲線將相應(yīng)地釋放升檔指令。例如工況一中，從靜止一檔以38%油門開度起步，一旦變速器輸出軸轉(zhuǎn)速達(dá)到500轉(zhuǎn)每分鐘，一二升檔線被從左到右穿過，一二升檔的指令即被觸發(fā)。

虛線為降檔線。當(dāng)工況點(diǎn)自右到左或自下到上或以以上兩種方向的組合穿過降檔曲線。換擋曲線將相應(yīng)的釋放降檔指令。例如工況二中六檔30%加速踏板油門開度穩(wěn)定在時(shí)速130公里駕駛，一旦加速踏板被踩到大于93%，則六五動(dòng)力降檔將被觸發(fā)。

換擋曲線是換擋策略控制中最重要的標(biāo)定內(nèi)容，其決定了駕駛性及舒適性?；镜膿Q擋曲線用于通用的駕駛工況。但同時(shí)，如果一些特殊的駕駛工況被軟件所識(shí)別，來(lái)自于換擋曲線的換擋請(qǐng)求將被限制或推遲釋放。通過這些特殊的功能標(biāo)定可以優(yōu)化動(dòng)態(tài)駕駛性，以下是一些特殊工況的舉例。

Some other special driving situations are summarized in Fig.8.保證傳動(dòng)系的穩(wěn)定性。.

其他一些特殊的駕駛工況入下圖。

圖8 特殊駕駛工況Fig.8 Special driving situations

環(huán)境條件

為了使車輛在任何工況以及環(huán)境條件下達(dá)到良好的駕駛性，匹配標(biāo)定的工作也需要在高寒，高溫以及高原環(huán)境下完成。

高寒測(cè)試：由于變速器的控制是由液壓系統(tǒng)實(shí)現(xiàn)，所以在低溫環(huán)境中變速箱油的粘度與常溫下有所不同，因此對(duì)換擋過程有較大的影響。在低溫狀況下為了達(dá)到同樣的駕駛表現(xiàn)，冬季需要在高寒地區(qū)進(jìn)行冬季標(biāo)定。同時(shí)一些換擋策略標(biāo)定如ESP換擋干涉，暖機(jī)模式也需要在冬季測(cè)試中標(biāo)定并驗(yàn)證。

在高溫環(huán)境中，變速器機(jī)油有可能會(huì)被加熱到超過100攝氏度而且發(fā)動(dòng)機(jī)表現(xiàn)也會(huì)不同。在夏季測(cè)試中，工程師將調(diào)整相關(guān)的變量以應(yīng)對(duì)這些特殊的變化。

在高原駕駛中，由于參與燃燒的氧氣稀薄，發(fā)動(dòng)機(jī)輸出的扭矩和功率會(huì)相對(duì)減少。變速器控制需要做出相應(yīng)的調(diào)整來(lái)應(yīng)對(duì)較低的氣壓對(duì)駕駛性帶來(lái)的影響。

總結(jié)

自動(dòng)變速器標(biāo)定需要工程師擁有全面的動(dòng)力總成，機(jī)械，液壓以及電力電子的知識(shí)。由于應(yīng)用匹配的過程需要經(jīng)歷冬季測(cè)試，夏季測(cè)試以及高原測(cè)試，所以完成整個(gè)項(xiàng)目需要較長(zhǎng)的開發(fā)周期。在這段時(shí)間中標(biāo)定工程師需要支持變速箱裝車啟動(dòng)，標(biāo)定每種工況的換擋過程，為達(dá)到最適合的駕駛性而標(biāo)定換擋策略，進(jìn)行極端環(huán)境測(cè)試。

標(biāo)定的最終的目標(biāo)是非常清楚的：為終端客戶提供良好的換擋表現(xiàn)與駕駛性。

Environmental Conditions

It has to be made sure that the system performs well in any kind of driving condition and in any kind of environmental conditions，such as cold climate，hot climate and driving at high attitudes.Therefore，the calibration work needs to include ride work in these conditions as well.

Cold climate trip：The transmission control is realized by hydraulic system.At cold temperature，the viscosity of the hydraulic oil changes and therefore impacts the shifting process strongly.To achieve good driving performance in a low temperature environment，winter tests and calibration work are carried out in cold places during winter.Some special ASIS functions like ESP shift inhibition，warm up model will be also calibrated and verified during this winter test.

In a hot climate，transmissions will be heated up over 100°C and the engine performances will be different as well.During summer test，the calibration engineer adjusts the control parameters to account for these changes.

During driving at high attitude the output torque and power will be less.Transmission control in high attitude places must be adapted against less engine performances in lower ambient pressure.

Summary and conclusion

Automatic transmission calibration requires knowledge about power train，mechanics，hydraulics and electric/electronic.As the calibration phase requires also driving in cold ＆hot climate，and at high altitude，a long term development is required for calibration projects.During that time calibration engineer supports the PIO （put in operation），calibrates shifting processes for every different shifting situation，calibrates shifting strategies to get best drivability，and goes to extreme environments tests.The target is clear：to provide the best shifting behavior and drivability to the end customer.