EST117B-降低單H操縱桿手動變速器同步故障的ZF變速器控制單元

目前很多OEM決定將雙H桿操縱系統改成為單H桿操縱系統以應用到手動變速器上(例如ZF公司的ECOSPLIT或ZF ECOMID)。

其背后的原因是為了減少換檔桿自身及在駕駛室中移動所需的空間,尤其是改善換檔的人機工程(見圖1和圖2)。

同時新方法將增加無意識的換檔過錯,這將導致超載,最壞情況下會導致變速器同步器的損壞。因此必須引入機械保護機構。

ZF公司開發的系統與TCU相聯,由一個閥室和連接在變速器上的氣動管路等組成,它能夠根據車輛的行駛狀況避免換檔過錯。

根據若干個安裝在變速器上的位置傳感器,將輸入軸和輸出軸的轉速和信號差與駕駛員需求相連,EST117B系統能夠允許或禁止變速器的換檔動作。這意味著通過定義一個或多個電磁閥的接通與斷開實現檔位范圍切換(1-4檔或5-8檔)和掛入副變速器或者禁止換檔過程的進行。

另外,當車速過高時系統將激活一個閥門以鎖定門電路避免誤選某一門電路。這時駕駛員將立即從操縱桿上獲得一個觸覺反饋。如果系統準備禁止換檔的話,可選擇激活蜂鳴器。

1 Introduction

Currently many OEMs2decide to change from double-H to single-H gear shift systems regarding their applications with manual shifted range gearboxes(for example ZF ECOSPLIT or ZF ECOMID).

The reasons behind this decision are a reduced amount of space needed for the shift knob and its movement within the driver's cabin and especially improved shift ergonomics(see Figure 1/Figure 2).

Simultaneouslythis new approach may increase the probability of unintended miss-shiftings that can lead to overload or in worst case to destruction of the synchro-units within the gearbox.Therefore the need to introduce a defined protection-mechanism arises.

ZF developed a system that-based on the com-bination of a TCU3,a valve box and the pneumatical connection to the gearbox-is able to support avoidance of miss-shiftings depending on the driving situation of the vehicle.

為了滿足中國、巴西、俄羅斯和印度等潛在市場的需求,ZF公司正設法找到成本和技術方面的平衡點。

因此,一方面信號界面很小(見圖6)硬件成本(包括TCU)便宜。另一方面TCU軟件提供一個完整的系統診斷、與CAN-bus(SAE J1939)的連接和UDS診斷協議。其中最新、最尖端的ZF軟件部分被用來產生協同作用和提供現代化技術。

2 單H操縱桿手動變速器

手動切換檔位范圍變速器(ZF-Ecomid和ZFEcosplit)采用了兩種不同的換檔模式：

?雙H操縱桿式(圖1)

圖1 雙H操縱桿式Fig.1 Double-H Shift Pattern

?單H操縱桿式(圖2)

雙H操縱桿模式被用于傳統的變速器換檔系統。包括1-4檔的低速檔和5-8檔的高速檔排列在一條線上。

如此排列需要一個長的選擇行程。現在這種特性不能滿足所有用戶的要求。越來越多的車輛制造商正在把雙H操縱桿改為單H操縱桿系統。

單H操縱桿模式改善了換檔人機工程,并且在駕駛室中的安裝空間小。理由是低檔組(GPL)和高檔組(GPH)的換檔模式重疊。

除了檔位切換機構之外,ZF Ecosplit可增加一個與換檔模式無關的副變速器(GVL/GVH)。該副變速器被用來細分原有的8檔以實現16個級差接近的前進檔。它由操縱手柄上的預選開關激活。通常,這些變速器都安裝稱作為ZF Servoshift的氣動輔助換檔裝置。

Based on several position switches within the gearbox,the input-shaft-and the output-shaft-revolution speed and different signals connected to the driver's demand,the EST117B system is able to release or inhibit the shifting of singlegearbox components.In detail this means that by defined(de-)activation of one or more solenoid valves the shifting of the range(gears 1 to 4 or gears 5 to 8)and the splitter(splitted gears)is allowed and executed or that this shift-process is prohibited and therefore will not be performed.

Additionally this system is able to activate a valve to lock single gates to avoid selecting a gate if the current vehicle speed is too high.In this case the driver gets immediate haptic feedback from the shift knob.Optionally a warning buzzer can beactivated if the system intends to prohibit an intended gear shift.

To satisfy the requirements of emerging markets like China,Brasil,Russia and India,ZF tried to find the correct balance between costs and stateof-the-art techniques and helpful features.

Therefore on one hand the signal interface is small(see Figure 6)and the hardware costs(including the TCU)are cheap.On the other hand the TCU software provides a complete diagnosticof the system,a connection to the CAN-bus(SAE J1939)and the diagnosticprotocol UDS on CAN.Internally the newest and most sophisticated ZF software components were integrated to use synergy effects and to offer state-of-the-art technology.

2 Manual Transmissions with Single-H

The manual range change transmissions(ZFEcomid[Figure 5]and ZF-Ecosplit[Figure 4])are available with tw o possible gearshift patterns：

?Double-H[Figure 1]

?Single-H[Figure 2]

The Double-H shift pattern represents the traditional gearshift system .The low range group(GPL),which comprises gear 1 to 4,and the high range group(GPH),with gear 5 to 8,are placed in line.

圖2 單H操縱桿式Fig.2 Single-H Shift Pattern

為確保單H桿變速器的順序換檔的舒適性和保護同步器免于誤換檔,必須增加一些輔助裝置。其中之一是被稱為E13模塊(圖3)的閥門閉鎖器.E13模塊由5個電磁閥組成,用來激活檔位切換、副變速器(ZF-Ecosplit)、伺服動力和若干保護功能。

圖3 單H桿換檔轉塔Fig.3 Single-H shift turret

圖4 單 H桿 Ecosplit 4變速器Fig.4 Ecosplit 4 with Single-H

This positioning requires a long select travel.Nowadays this characteristic does not fulfil the requirements of each customer.Increasingly the vehicle manufacturers replace the Double-H gearshift system by a Single-H gearshift system.

The Single-H shift pattern improves the ergonomic of shifting and needs less installation space in the driver's cab.Reason is the superimposition of shift patterns of low range group(GPL)and high range group(GPH).

Besides the range change group an additional splitter group(GVL/GVH)is available for ZFEcosplit transmissions which is independent of the gearshift pattern.The splitter group can be used to sub-divide the 8 speeds once again to a total of 16 closely-stepped forward speeds.It is actuated by a pre-select switch on the shift knob.Generally these transmissions are equipped with a pneumatic shift assistance known as ZF Servoshift.

To ensure a comfortable shift sequence of manual transmissions with Single-H and to protect the synchronizers against miss-shiftings several additional components are required.One component is a valve block,called E13 module(Figure 3).The E13 module contains five solenoid valves,which are used for the actuation of range change group,splitter group(ZF-Ecosplit),servo power and several protection functionalities.

3 EST117B-Protection Functions

The transition from Double-H to Single-H gearshift system may increase the risk of unintended miss-shiftings by the driver.

For instance if the driver intends to shift from 4th gear into 5th gear,the range change group has to be changed from GPL to GPH.But if the driver forgets to operate the GP preselection switch,which is placed on the shift knob,no range change will take place.The transmission stays in GPL and without protection functions4 this shifting procedure w ould lead to a miss-shifting from 4th gear in-to 1st gear(instead of intended 5th gear).Thereby the synchronizer might be damaged by too high friction speed,and even worse overspeeds of the engine and clutch disk could occur.

圖5 帶緩速器的單H桿Ecomid變速器Fig.5 Ecomid with Single-H and Intarder

3 EST117B-保護功能

換檔系統從雙H桿轉化為單H桿將增加駕駛員的無意識換檔錯誤。

例如如果駕駛員決定從4檔切換到5檔,動力傳遞路線將從GPL轉換到GPH。但是如果駕駛員忘記操作安裝在換檔手柄上的GP預選開關,將不會出現檔位范圍的切換。變速器仍然處于GPL工作狀態,如果沒有保護功能的話這次換檔將導致從4檔到1檔(而不是5檔)的錯誤換檔。因而同步器由于過高的摩擦速度而受損,甚至會出現更嚴重的發動機和離合器從動盤的超速。

為避免這些無意識的換檔錯誤,ZF提供了特殊的保護功能。

門互鎖：當被定義的變速器輸出軸轉速超出時,進入門1/2(GPL)或門5/6(GPH)的通道被禁止因而閉鎖。

檔位范圍互鎖：當被定義的變速器輸出軸轉速超出時,進入低檔范圍(GPL)被禁止因而閉鎖。

伺服空氣切斷：一旦離合器踏板沒有完全踩下,伺服換檔的氣壓助力不起作用。

4 EST117B-界面示意圖

下圖(圖6)給出了EST117B的界面示意圖。

5 117B-軟件

最重要的目標之一是必須開發一套在新興市場例如金磚四國具有競爭力的系統。因此其特殊需要在于系統耐用性和技術簡單化方面的提升：與歐洲相比,由于缺乏足夠的維修網絡和各自不同的地形而需要高可靠性的車輛。同時所提供的功能將能夠直接支持駕駛員和系統自身,并控制在一個可接受的價格上。

這些需求直接影響系統的構建。以下的表格(表1)給出了所需的信號和責任方：

信號界面簡單易懂并且能夠將物理信號直接與TCU相聯或通報給SAE J1939 CAN總線(見圖6)。

To avoid these unintended miss-shiftings ZF provides special protection functions.

Gate interlock：Above defined output shaft speed of transmission the access into gate 1/2(GPL)or gate 5/6(GPH)is not allowed and therefore locked.

Range interlock：Above defined output shaft speed of transmission the access into low range group(GPL)is not allowed and therefore locked.

Servo air cut off：As long as the clutch pedal is not pressed completely the air support for Servoshift is deactivated.

4 EST117B-Interfaces Diagram

The following picture(Figure 6)shows the interface diagram of the EST117B in the current available configuration.

5 EST117B-Software

One of the most important targets w as to develop a system that is able to compete in emerging markets like the BRIC5-states.Therefore specific requests to system roughness and technical simplicity arise：compared with Europe there is no dense service net available and geographical respective geopolitical reasons require high vehicle availability.Simultaneously the provided functionality shall directly support the driver and the system itself and is available at an acceptable price.

These requests directly influence the system architecture.The following table(Table 1)displays the needed signals and the current responsible party：

The signal interface is straightforward and can be provided either by physical signals directly connected to the TCU or by messages on SAE J1939 CAN bus(see also Figure 6).

The small amount of necessary signals makes it easy for an OEM to integrate this system into his vehicle.For ZF it means-combined with the request formulated in the beginning of this chapter-to develop a high-sophisticated diagnosis that on the one hand recognizes each possible failure(and therefore protects the driver and the system)but on the other hand ensures a high vehicle availability.

圖6 界面示意圖Fig.6 Interface diagram

所需信號最少使得OEM能夠很方便地將其集成到整車系統中。對于ZF而言,這意味著能夠與本節開始時所闡述的需求結合起來開發出一套高度復雜的診斷系統,一方面能夠識別各種可能的故障(因而能夠保護駕駛員和系統),另一方面提高了車輛的可用性。

Figure 7 shows the software architecture of this system.

Below a short description of the visible design elements(Table 2)：

Despite the fact that the safety classification(according to IEC61508)for this system resulted in SIL0,the softw are is structured close to safety-relevant systems.A diagnosticmonitor software component exists for every incoming signal.Task of this component is to perform a plausibility check for its assigned signal.This check is executed either based on a redundant signal or on defined plausibility logic.Additionally these diagnostic monitors are connected within a prohibition matrix to solve the problem of signal interleaving.The resulting output of the protection function software component is a request to activate valves of the valve module.The activation is checked by an additional software unit called substitute functions.This unit evaluates-based on the results of the protection and plausibility functions-if a valve is allowed to become active or not and therefore becomes one of the central software parts.

表2 部件功能Table 2 Design Elements

圖7 EST177B軟件體系結構Fig.7 Software Architecture EST117B

雖然該系統的安全等級(根據 IEC61508)是SIL0,其軟件結構接近于軟件相關系統。診斷監控器的軟件適用于如何輸入信號。該軟件的任務是對指定的信號進行真實性檢驗。該項檢驗基于冗余信號或所定義的似然性邏輯。另外,這些診斷監控器與禁止矩陣相聯以解決信號交叉存取的問題。保護功能軟件的輸出結論作為激活閥門的一個要求。該項激活受控于被稱為替換功能的附加軟件。根據保護功能和似然性功能作出評價決定是否激活,這成為核心軟件的一部分。

The combination of ZF Errorhandler and the diagnostic protocol UDS6(or diagnostic messages according SAE J1939-73)allows the OEM to communicate directly with the TCU to gather deeper informations about emerged errors.

Substitute functions(that means：the reaction of the system in case of a failure)try to find the balance between a high vehicle availability and the possibility to protect the system of damages.

Due to the high flexibility of the implemented software architecture customisation to new customer requests are possible.Currently the software recognizes 45 different errors,supports 11 diagnostic monitors and 10 different substitute functions that are also evaluated by means of two different prohibition matrices.

As mentioned above,regarding the protection functions a special approach was taken(also mentioned above).In the last years a new software creation process definition called Model Based Soft-ware Engineering became more and more important to current projects.

ZF Errorhandler和 UDS診斷協議(或根據SAE J1939-73診斷信息)的結合可使OEM直接和TCU通訊,從而獲得有關故障的深層次信息。

替換功能(出現故障時系統的反應)則試圖在車輛高可用性和預防系統受損方面找到一個平衡。

由于軟件結構編輯模式的高度靈活性,使得更新用戶要求變成可能。目前軟件能夠識別45種不同的錯誤、支持11種診斷模式和10種不同的替換功能并能根據兩種不同的禁止矩陣作出評價。

In this project the MBSE process was used to implement the protection functions.Reasons why it was used in EST117B：

?Common development language that allow s both developer of functions and software developer to discuss about the same topic on a common base

?Possibility for rapid prototyping to evaluate new functionalities directly in a SiL7simulation environment

?Flexibility to add new customer-related requests into the protection functions

The implemented model currently consists of approximately 1800 modelling elements.The following picture(Figure 8)shows an excerpt(func-

圖8 EST117B功能模塊Fig.8 Excerpt of EST117B functional model輔助功能 Auxiliary Functions

正如上述所及,對于保護功能而言具有一個特殊的途徑。去年新開發的M odel Based Softw are Engineering軟件對于目前方案正變得越來越重要。

在該方案中,MBSE程序被用來實現保護功能。其采用EST117B的理由如下：

?通用開發語言使得功能開發者和軟件開發者能夠在公共平臺上討論相同的問題。

?能夠利用快速原型直接在SiL仿真環境中評價新功能。

?其靈活性使得能夠在保護功能中添加用戶相關的需求。

目前執行模塊包含有約1800個模塊單元。下圖(圖8)在功能層面上摘錄了MBSE模塊。

6 結論

ZF公司的研發成果被證明在耐用性、靈活性和成本方面能夠滿足新興市場之需求。在經歷了一年的耐久性試驗和對EST117B系統稍作優化后,將于2011年向優化推出系列產品。tional layer)of the MBSE8-model.

6 Summary

This ZF development proved that all requirements for emerging markets(like robustness,flexibility and price awareness)can be fulfilled.

With the completion of the one year lasting field test,which included also slight optimizations for the EST117B system,the series start-up of the system lead customer will be launched in July 2011.

附錄 Appendix

iOriginal Equipment Manufacturer

2Original Equipment Manufacturer

3T ransmission Control Unit

4Corresponding to described ex ample the gate interlock would avoid miss-shifting into 1st gear

5BRIC：Brasil,Russia,India,China

6Unified diagnostic services(ISO 14229-1)

7Software in the Loop：closed simulation loop that is driven by a vehicle/track model

8Model Based Software Engineering：model driven software development including autocode-generation