As vehicle comfort and convenience features continue to proliferate, Matthew Beecham reports on some of the consequences for the vehicle’s electrical and electronic architecture.
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Like most auto parts, the need to reduce cost, cut emissions, improve fuel economy and safety are the main forces driving the electrical and electronic distribution systems market. Manufacturers point out that the increasing use of electronics hard- and software can significantly help address these concerns.
Meanwhile, motorists’ insatiable demand for comfort and convenience features is posing new challenges to manufacturers in terms designing each new vehicle’s electrical and electronic architecture. While they must continually come up with novel ways of packaging certain solutions, they must also balance this need with keeping costs under control by reusing modules, functionalities, hardware and software parts wherever possible. For manufacturers, the increase in the content and complexity of electrical and electronic components also requires a broader overall design perspective. This shift in design philosophy is, as Lear Corp describes it, “moving from the wire itself to the wire ends”, reflecting a view that design should include both the wiring and the electromechanical and electronic devices to which they are connected.
Pascal Degardins, managing director of Intedis, believes that there are two consequences of the increased complexity in the vehicle’s electrical and electronic architecture. He told us: “First, the increasing number of leads in the wiring harness has generated weight and bundle diameter issues. The increasing number of ECUs is also resulting in packaging issues. Second, the increase of the communication complexity — or the interactions between functions – has led to a significant increase in development and integration time, often resulting in quality issues and delayed start or production.” Intedis is a 50/50 joint venture between Hella and Leoni. Headquartered in Wurzburg, Germany, the company designs and manufactures systems for the vehicle’s electrical and electronic distribution system. The main thrust of the company’s R&D programme is centered on developing customised wiring systems, modular integrated solutions, flat wire technologies, and gateway communication systems.
According to James Miller, superintendent of process engineering for Delphi Packard Electrical/Electronic Architecture, consumer demand and competitive pressures are forcing carmakers to add a growing number of innovative features to their vehicles, a circumstance that impacts E/E architecture and components. The seminar went on to discuss current component trends that affect connectors, terminals and seals, cables and their impact on existing processes. As an example of what carmakers are looking for today, Delphi points to its Halogen Free Ultra Thin-Wall Cable that is environmentally-friendly and durable while also being thinner and lighter in weight than traditional cable.
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By GlobalDataWhile talk of “low-cost architecture” is used quite often in industry circles, what does that mean in reality? “There are different levels of low cost,” said Degardins: “Europe currently targets €5,000 to €7,000 (e.g. for the Logan) whereas the BRIC [Brazil, Russia, India and China] focuses on €1,500 to €3,000. The European strategy is rather to downgrade the standard €10,000 vehicles, whereas the BRICs require completely new approaches.
“Functional requirements are also very important. For a very simple function like internal lighting, the total cost of ownership (i.e. end customer price) can vary in a ratio of 1 to 10. What is the perceived value for the end customer of a dimming function? Intedis specialises in so-called “function benchmarking,” i.e. comparing different vehicles in the target segment and the way they implemented functions, analysing the functional drawings to determine a price per function and team-work with the marketing / purchasing divisions of the OEM to help them freeze their functional content.
“The scalability is another major criterion. The complete platform must be optimised, not a single “cost control model”. If you optimise the low end in order to get an attractive “entry price” then your high end vehicles will have a lot of standalone ECUs and cut leads. If you optimise the high end, your low end will have a lot of giveaway costs, e.g. ECUs used at 50% of their capacity.
“In addition, mechatronics integration is the key for cost, weight and quality optimisation. As a sister company of electronics specialist Hella and wiring harness supplier Leoni, Intedis is optimally placed to combine the best of both technologies. These are, for example, electronic fusing solutions (or so-called mart junction boxes), battery modules (complete intelligent energy management and distribution units), intelligent flex solutions.”
The modern vehicle electrical system is certainly becoming more and more complex. Sumitomo Wiring Systems estimates that there are some 3,000 electric wires built into a modern car. All of these electric wires and related parts are bundled into wiring harnesses to increase their efficiency and reduce their size for easy installation. Wiring harnesses serve to electrically connect electronic and electrical components and to relay transmission of information and electric power between the components. Each electric wire in a wiring harness plays a different role, such as taking electric power from power supplies, sending sensor signals and communicating operational information.
Alternative solutions to the traditional wire harness loom include multiplexing, fibre optics and flexible printed circuit boards. Multiplexed systems need fewer wires, thereby reducing bulk and weight. Information is shared rather than duplicated, improving service repair, diagnostics and the flexibility to change options. Fibre optic systems transmit information and data throughout the vehicle for signaling and communication. Claimed advantages of using fibre optics over copper wires include weight saving and higher data quality, reliability and integrity. Not only is it possible to send large volumes of data through the network at the speed of light, it also guarantees excellent electromagnetic compatibility. On the downside, however, fibre optics is more expensive than traditional wire harness technology as it requires more parts to convert electrical signals to light pulses and back again.
In terms of the further use of fibre optics in the vehicle, Degardins believes that the issue is not so much the technology or the process — which are now mature and of acceptable cost – but with the application itself. “In other words, where do we really need such a bandwidth in the car? And the concurrence of coaxial solutions which have now reached a fully satisfying performance in terms of noise immunity. MOST [media oriented systems transport] was intended to be the key application for optical fibre. More than ten years later, MOST remains a very expensive solution. It generates significant extra costs at the ECU level (i.e. MOST chips, network management software), is hardly down-scalable (i.e. expensive for a simple radio / telephone interconnection) and is as standard not precise enough to allow inter-operability. The replacement of MOST by Ethernet would definitively kill automotive fibre.”
Over the past few years, a number of industry groups have emerged aimed at developing common standards in the vehicle electrical and electronic arena. For example, AUTOSAR (AUTomotive Open System ARchitecture) was set up by carmakers and automotive equipment manufacturers to develop a standardised international electric/electronic architecture concept for vehicles.
AUTOSAR’s core partners include BMW, Bosch, Continental, Daimler, Ford, Opel, PSA Peugeot Citoren, Toyota and VW. Its ‘premium’ members (i.e. without a vote) include Alpine, Autoliv, Delphi, Denso, Hella, Johnson Controls, Lear, Magna, Magneti Marelli, TRW, Valeo and ZF.
In the early days of AUTOSAR, some felt that was a danger that achieving a level of standardisation might cost suppliers the lucrative position of being system integrators. However, Gerulf Kinkelin, director of research and innovation, PSA Peugeot Citroën and spokesman for AUTOSAR believes that fear is probably behind us. He told us: “It is clear for everybody today that adopting AUTOSAR will considerably reduce the recurring redevelopment of software by introducing a high level of independence between the hardware platform and the applicative software modules. The experience shows that AUTOSAR allows several different business models to be applied, depending on the context.”
When AUTOSAR was formed in July 2003, there was said to be concern among suppliers that carmakers would use the standard to turn proprietary-technology modules and systems into commodity products. The real issue today is to adapt the automotive industry to the strong economic challenges it has to face. “Collective efficiency associated with software reuse and easy integration benefits to all the actors in the market place, by reducing overall development and adaptation costs, and offering the final customers more affordable cars, to achieve higher sales,” said Kinkelin.
Is the industry ultimately moving toward ‘plug-and play’, as seen in the computer industry? Taking the idea of multiplexing to its logical extreme, a carmaker could potentially wait until relatively late in the vehicle’s development cycle before committing to specific electronic hardware yet avoid having to delay – or worse, tear up – its electrical architecture in the last minute. “The issue is mainly software reuse and a higher level of interoperability between ECUs and functions,” adds Kinkelin. “Although architectures and software modules are becoming standard, allowing a faster integration, the validation phases will still exist to achieve the very high level of reliability asked for in the automotive world. Plug-and-play as seen in the computer industry is not the primary target today.”
Matthew Beecham
‘Beechy’
