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Efficient vehicle electronics

Modern vehicle electronics engineering has turned automotive manufacturers into system integrators par excellence. In the development of new vehicles, electronic control units from different manufacturers have to be linked together to form a reliable network. Despite the increasing complexity of vehicle electronics, there is an increasing demand for shorter development times and lower costs for the systems engineering stage. MG Rover, the UK automotive manufacturer, has successfully managed to sustain the balancing act between lower budgets on the one hand and faster development times on the other by using products from Volcano Communications Technologies.

	The Volcano Tool Chain provides an integrated standardised development environment that includes all the work steps required for engineering communications systems
	The new engine in the Rover 75/MG ZT will be used in future vehicles without the need to re-design the network interfaces

The complexity of electronic architectures in modern vehicles has meant that besides developing suitable hardware components, one of the main responsibilities of engineers is to ensure safe communication between the individual electronics network components. Today, almost 70 ECUs (electronic control units) exchanging thousands of signals are integrated into a vehicle in the luxury class. The exact number of signals used by each ECU depends on the unit’s function. Although an immense amount of time and effort is now required to integrate all the parts systems into one efficient standardised system, automotive manufacturers’ marketing departments still demand faster engineering times on a minimum development budget. This task becomes almost impossible if these engineering departments do not use high-performance development environments.

“Our electronic systems engineering department employs approximately 50 people. We rely on a high-performance development environment to complete vehicle electronics projects within a set timeframe,” says Peter Bailey, chief engineer of electrical systems at MG Rover Group, to describe the special demands on his team of engineers.

Immediate success with first project

At the beginning of 2003, MG Rover invested in the integrated development environment from Volcano Communications Technologies to support engineers in the design and implementation of electronic systems. The Volcano Tool Chain supports in the design of complex vehicle electronic systems with a structured systems engineering approach: it provides modules specialised to the given task for the important engineering stages. The advantages of this development environment in comparison to the traditional approach were visible during the first engineering project.

“The new engineering environment was first used to design and engineer a new electronic engine control for its large car platform – the Rover75 and MG ZT. Our objective was to design an engine for the Rover 75/MG ZT in compliance with the new Euro 4 exhaust emissions standards,”, says Derek Hoyle, group leader at MG Rover responsible for the embedded applications, the first project designed with the Volcano Tool Chain. In the design of the new Rover 75/MG ZT engine, the MG Rover engineers decided to configure the ECU application software in such a way that it could be adapted to the Rover75/MG ZT vehicle environment and could, at the same time, be used for other model series in the future.

Flexible design with interface layer

During the project, it was of considerable importance to MG Rover engineers that the investments involved in developing this application to comply, for example, with Euro 4 standards, should, if at all possible, be calculated separately from the specific network features of other vehicle model series. This meant that application-related information had to be strictly separated from network-related information. The Volcano Network Architect (VNA) in combination with the Volcano Target Package (VTP) supported them in this objective. With the help of both these tools, the application is strictly partitioned from any networking details and they provide the engineer with a signal-based model as well as an API (application programming interface). All signal requirements are firstly defined using a public/subscribe module. The signals, that can be sent and received by the ECU, are defined for each ECU in order to execute local functions, for example. The ECU programmer then has access to the signal model defined during this process. Once the Volcano software has been loaded onto the ECU, an interface layer is then set up which receives the signal information from the incoming network data. This information is then transferred to the application in the required format.

This concept enables the application to be developed independently of the vehicle network structure offering numerous decisive benefits. Firstly, the engineer can donate more time and attention to the application than was previously the case and secondly, the application is not affected by any modifications to the network structure. This means that existing applications, such as the electronic engine control, can be adapted to new vehicle models without any difficulty.

Implementation costs cut by half

“To gain the full benefits of the system, we first had to input the Rover 75/MG ZT network structure and model it in the VNA. Once this had been completed, we were able to profit immediately with the first implementation of the electronic engine control in the current model. We can now use this model for all subsequent vehicle series which will cut the time and costs involved by approx. 50%,” says Nic Webb, ICE & electronics section manager, who underlines the economic benefits resulting from the use of this integrated development environment.

Although a considerable amount of time was needed to input the current Rover 75/MG ZT network structure required for modelling the new network structure, the time and cost-saving effects were visible within the first project. Prior to the introduction of VNA, any changes to the network structure meant extensive modifications to almost all the ECUs in the vehicle electronics system. The control software for each separate ECU had to be manually changed in C, loaded into the ECU and tested. MG Rover’s product engineering department had to rely on the external support of suppliers for interfacing, such as implementing a new control unit in the development environment.

Depending on the complexity of the interfacing process, the suppliers would need approx. six months for signal integration and validation. As a result of the integrated development environment and the single input of the Rover 75/MG ZT network structure, MG Rover’s engineering department was able to manage the entire engineering process on its own. Services that had been provided by external service providers could be resourced which meant that implementation costs could be halved.

“We are not only saving costs in the development of new vehicle series but time as well,” says Hoyle. “Once the network structure has been modelled once in the VNA, we now require three months instead of six to 12 months to integrate the electronic control units in a new model series.”

More independence from manufacturers

“Besides time and costs savings, other decisive advantages of Volcano Engineering are the flexibility and independence provided by such an environment.

“We no longer have to rely heavily on certain manufacturers now in terms of the hardware used for the vehicle electronics architecture and even in the use of ECUs,” says Webb. In the past, MG Rover was committed to one certain manufacturer once an electronic control unit had been successfully integrated. It can now can change suppliers without any difficulty. To integrate a new control unit, the provider now only needs to store the VCT library – provided by Volcano or another system integrator – in the control unit. In conjunction with the interface layer, the actual application can now be transferred unchanged to the new target platform after running the compiler. The development environment supports all the work steps required for this process.

Development environment

Volcano Communications Technologies concentrates on the engineering of vehicle communication systems and provides all the necessary tools for an integrated development environment. The functions are closely based on the principles of systems engineering. The tool set is based on a central signal database containing information concerning the functions and network structure – for example, CA- of the ECUs as well as for defining all sub-networks such as LIN, MOST and FlexRay. Once the electronic architecture functions have been captured, the frame compiler interprets the contents of the signal database and calculates the frame requirements for the entire vehicle based on the parameters of the function model. By using the software to pack different signals together, the frame compiler can reduce the activities on the CAN bus. An engineer, in contrast, could not achieve the same results without the necessary tools as the overall structure is far too complex and the interactivity of the dependencies is too difficult to analyse.

The frame compiler results are used to calculate and parameterise the configuration data for all ECUs. Numerous parameters for each ECU are also defined during this process. Furthermore, the frame compiler also generates the set up and the filter to ignore unimportant CAN frames for one node thus reducing the local requirements on CAN data processing. The frame compiler is also responsible for defining the timeframe and transfer pattern of each sent CAN frame as well as the positioning of signals within the data frames.

The Volcano engineering concept has been successfully implemented in numerous engineering projects and since 1998 has been used throughout Volvo’s large platform – XC90, S80, S/V/XC70 and S60 series – as well as its new small platform – S40, V50. More than 20 million cars, with an average of 20 ECUs per car, have already been programmed in this environment and are operating efficiently.

Strategic integration of ECU suppliers

Although the Volcano tool set comprises numerous integrated modules, MG Rover engineers quickly familiarised themselves with the new development environment. “After a two day training, we had familiarised ourselves with the VNA and were ready to start with the modelling of the Rover 75/MG ZT network within two weeks,” says Hoyle.

The Volcano support team was constantly on hand to help during the network set-up stage and provided direct support when any questions arose. Due to its satisfaction with the first project, MG Rover now plans to integrate the rest of the ECUs into forthcoming products. MG Rover suppliers will be equipped with the Volcano Target Package (VTP), the necessary programming environment – API – as well as the software libraries containing the function requests successively.

“We have decided to develop all new vehicle electronics architectures and ECUs with the Volcano Tool Chain and to integrate our suppliers into this process step by step,” says Hoyle. With every new hardware manufacturer that MG Rover integrates into the new engineering concept, the flexibility and speed with which the engineering team can react to new market requirements increases. This contributes considerably to the competitiveness of the British automotive manufacturer.