EST117B－降低单H操纵杆手动变速器同步故障的ZF变速器控制单元

Dipl.－Ing.（BA）Sabrina Broschat，ZF Friedrichshafen AG Dipl.－Ing.（FH），Dipl.－Math.（FH）Timo－Bastian Konkol，ZF Friedrichshafen AG

目前很多OEM决定将双H杆操纵系统改成为单H杆操纵系统以应用到手动变速器上（例如ZF公司的ECOSPLIT或ZF ECOMID）。

其背后的原因是为了减少换档杆自身及在驾驶室中移动所需的空间，尤其是改善换档的人机工程（见图1和图2）。

同时新方法将增加无意识的换档过错，这将导致超载，最坏情况下会导致变速器同步器的损坏。因此必须引入机械保护机构。

图1 双H操纵杆式Fig.1 Double－H Shift Pattern

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 Figure1/Figure2）.

Simultaneously this 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 TCU，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.

图2 单H操纵杆式Fig.2 Single－H Shift Pattern

ZF公司开发的系统与TCU相联，由一个阀室和连接在变速器上的气动管路等组成，它能够根据车辆的行驶状况避免换档过错。

根据若干个安装在变速器上的位置传感器，将输入轴和输出轴的转速和信号差与驾驶员需求相连，EST117B系统能够允许或禁止变速器的换档动作。这意味着通过定义一个或多个电磁阀的接通与断开实现档位范围切换（1－4档或5－8档）和挂入副变速器或者禁止换档过程的进行。

另外，当车速过高时系统将激活一个阀门以锁定门电路避免误选某一门电路。这时驾驶员将立即从操纵杆上获得一个触觉反馈。如果系统准备禁止换档的话，可选择激活蜂鸣器。

为了满足中国、巴西、俄罗斯和印度等潜在市场的需求，ZF公司正设法找到成本和技术方面的平衡点。

因此，一方面信号界面很小（见图6）硬件成本（包括TCU）便宜。另一方面TCU软件提供一个完整的系统诊断、与CAN－bus（SAE J1939）的连接和UDS诊断协议。其中最新、最尖端的ZF软件部分被用来产生协同作用和提供现代化技术。

2 单H操纵杆手动变速器

手动切换档位范围变速器（ZF－Ecomid和ZFEcosplit）采用了两种不同的换档模式：

· 双H操纵杆式（图1）

· 单H操纵杆式（图2）

双H操纵杆模式被用于传统的变速器换档系统。包括1－4档的低速档和5－8档的高速档排列在一条线上。

如此排列需要一个长的选择行程。现在这种特性不能满足所有用户的要求。越来越多的车辆制造商正在把双H操纵杆改为单H操纵杆系统。

单H操纵杆模式改善了换档人机工程，并且在驾驶室中的安装空间小。理由是低档组（GPL）和高档组（GPH）的换档模式重叠。

除了档位切换机构之外，ZF Ecosplit可增加一个与换档模式无关的副变速器（GVL/GVH）。该副变速器被用来细分原有的8档以实现16个级差接近的前进档。它由操纵手柄上的预选开关激活。通常，这些变速器都安装称作为ZF Servoshift的气动辅助换档装置。

为确保单H杆变速器的顺序换档的舒适性和保护同步器免于误换档，必须增加一些辅助装置。其中之一是被称为E13模块（图3）的阀门闭锁器.E13模块由5个电磁阀组成，用来激活档位切换、副变速器（ZF－Ecosplit）、伺服动力和若干保护功能。

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 EST117Bsystem is able to release or inhibit the shifting of single gearbox components.In detail this means that by defined（de－）activation of one or more solenoid valves the shifting of the range（gears 1to 4or gears 5to 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 agate 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 be activated 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 Figure6）and the hardware costs（including the TCU）are cheap.On the other hand the TCU software provides a complete diagnostic of the system，a connection to the CAN－bus（SAE J1939）and the diagnostic protocol 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［Figure5］and ZF－Ecosplit［Figure4］）are available with two possible gearshift patterns：

· Double－H ［Figure1］

·Single－H ［Figure2］

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

图3 单H杆换档转塔Fig.3 Single－H shift turret

图4 单H杆Ecosplit 4变速器Fig.4 Ecosplit 4with Single－H

图5 带缓速器的单H杆Ecomid变速器Fig.5 Ecomid with Single－H and Intarder

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 8speeds 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 E13module（Figure3）.The E13module 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 functions4this shifting procedure would lead to a miss－shifting from 4th gear into 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.

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.

3 EST117B－保护功能

换档系统从双H杆转化为单H杆将增加驾驶员的无意识换档错误。

例如如果驾驶员决定从4档切换到5档，动力传递路线将从GPL转换到GPH。但是如果驾驶员忘记操作安装在换档手柄上的GP预选开关，将不会出现档位范围的切换。变速器仍然处于GPL工作状态，如果没有保护功能的话这次换档将导致从4档到1档（而不是5档）的错误换档。因而同步器由于过高的摩擦速度而受损，甚至会出现更严重的发动机和离合器从动盘的超速。

为避免这些无意识的换档错误，ZF提供了特殊的保护功能。

门互锁：当被定义的变速器输出轴转速超出时，进入门1/2（GPL）或门5/6（GPH）的通道被禁止因而闭锁。

档位范围互锁：当被定义的变速器输出轴转速超出时，进入低档范围（GPL）被禁止因而闭锁。

伺服空气切断：一旦离合器踏板没有完全踩下，伺服换档的气压助力不起作用。

4 EST117B－界面示意图

下图（图6）给出了EST117B的界面示意图。

4 EST117B－Interfaces Diagram

The following picture（Figure6）shows the interface diagram of the EST117Bin the current available configuration.

图6 界面示意图Fig.6 Interface diagram

5 117B－软件

最重要的目标之一是必须开发一套在新兴市

场例如金砖四国具有竞争力的系统。因此其特殊需要在于系统耐用性和技术简单化方面的提升：与欧洲相比，由于缺乏足够的维修网络和各自不同的地形而需要高可靠性的车辆。同时所提供的功能将能够直接支持驾驶员和系统自身，并控制在一个可接受的价格上。

这些需求直接影响系统的构建。以下的表格（表1）给出了所需的信号和责任方：

表1 车辆功能界面Table1 Vehicle functional interface

信号界面简单易懂并且能够将物理信号直接与TCU相联或通报给SAE J1939CAN总线（见图6）。

5 EST117B－Software

One of the most important targets was 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（Table1 ）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 Figure6）.

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.

Figure7shows the software architecture of this system.

Below a short description of the visible design elements（Table2 ）：

图7 EST177B软件体系结构Fig.7 Software Architecture EST117B

所需信号最少使得OEM能够很方便地将其集成到整车系统中。对于ZF而言，这意味着能够与本节开始时所阐述的需求结合起来开发出一套高度复杂的诊断系统，一方面能够识别各种可能的故障（因而能够保护驾驶员和系统），另一方面提高了车辆的可用性。

表2 部件功能Table2 Design Elements

虽然该系统的安全等级（根据IEC61508）是SIL0，其软件结构接近于软件相关系统。诊断监控器的软件适用于如何输入信号。该软件的任务是对指定的信号进行真实性检验。该项检验基于冗余信号或所定义的似然性逻辑。另外，这些诊断监控器与禁止矩阵相联以解决信号交叉存取的问题。保护功能软件的输出结论作为激活阀门的一个要求。该项激活受控于被称为替换功能的附加软件。根据保护功能和似然性功能作出评价决定是否激活，这成为核心软件的一部分。

Despite the fact that the safety classification（according to IEC61508）for this system resulted in SIL0，the software is structured close to safety－relevant systems.A diagnostic monitor 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.

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 45different errors，supports 11diagnostic monitors and 10different 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 Software Engineering became more and more important to current projects.

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

ZF Errorhandler和UDS诊断协议（或根据SAE J1939－73诊断信息）的结合可使OEM直接和TCU通讯，从而获得有关故障的深层次信息。

替换功能（出现故障时系统的反应）则试图在车辆高可用性和预防系统受损方面找到一个平衡。

由于软件结构编辑模式的高度灵活性，使得更新用户要求变成可能。目前软件能够识别45种不同的错误、支持11种诊断模式和10种不同的替换功能并能根据两种不同的禁止矩阵作出评价。

正如上述所及，对于保护功能而言具有一个特殊的途径。去年新开发的Model Based Software Engineering软件对于目前方案正变得越来越重要。

在该方案中，MBSE程序被用来实现保护功能。其采用EST117B的理由如下：

·通用开发语言使得功能开发者和软件开发者能够在公共平台上讨论相同的问题。

·Common development language that allows 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 1800modelling elements.The following picture（Figure8）shows an excerpt（functional 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.

图8 EST117B功能模块Fig.8 Excerpt of EST117Bfunctional model

· 能够利用快速原型直接在SiL仿真环境中评价新功能。

·其灵活性使得能够在保护功能中添加用户相关的需求。

目前执行模块包含有约1800个模块单元。下图（图8）在功能层面上摘录了MBSE模块。

6 结论

ZF公司的研发成果被证明在耐用性、灵活性和成本方面能够满足新兴市场之需求。在经历了一年的耐久性试验和对EST117B系统稍作优化后，将于2011年向优化推出系列产品。

With the completion of the one year lasting field test，which included also slight optimizations for the EST117Bsystem，the series start－up of the system lead customer will be launched in July 2011．

iOriginal Equipment Manufacturer

2Original Equipment Manufacturer

3Transmission Control Unit

4Corresponding to described example 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