The LIN-Bus and its contribution to eco-friendly vehicles

Rising crude oil prices and perceptible climatic changes worldwide have sharpened consumers' ecological awareness. These developments have not stopped short of the automobile — but is there such a thing as a green car? Of course not — or rather, not yet. But the prospects are not that bad. Today's engines, for instance, have many times the power of 20 years ago, but their fuel consumption has decreased by almost one-third.

Factors that reduce consumption

The weight of a vehicle and the electronic systems active in it are the main factors in reducing consumption and thus lowering CO2 emission. Some 30 years ago, functions like power-assisted steering, active and passive safety or air-conditioning were almost unheard of, but today they are part and parcel of even the basic models. And it is precisely these (and many more) features that make up the main portion of the additional weight. In all non-electrical sectors, the automotive industry has already exhausted its potential for savings. First the paint, which is applied in quantities that are a fraction of what they once were, then the steel sheets used, which have been pared down to minimal thickness and have already been replaced in part by significantly lighter materials such as plastic, aluminum or even compound materials (carbon fiber). Wherever possible, even glass is being replaced by the much lighter polycarbonate.

The role of the LIN Bus

Further potential for savings can therefore be exploited only through the use of intelligent electronics. In this area, bus systems have a special part to play, because they not only lead to a reduction in the wiring itself, thus reducing the weight of the vehicle, but also allow LIN nodes to be made more intelligent, and individual nodes to be switched off when not needed.

The LIN network is only one of many bus systems in use in motor vehicles, but it is the cheapest in terms of cost per node. Looking at the innovations of recent years, and their penetration of the market, developments in the LIN segment can be compared with those in the area of EPS (Electrical Power Steering). Both LIN and EPS are aimed at the low-cost market segment, and achieve their distribution through high volumes rather than through the price " in complete contrast to the ABS system or the airbag, for example. So the main potential for LIN, from a worldwide perspective, lies in the high-volume platforms of the car manufacturers. And the fields of application are many and varied, from air-conditioning networking or door modules, which even today are networked first and foremost with LIN, through light control and switch modules in the passenger area, where cabling is nowadays mostly direct, to flap control (e.g. Exhaust Gas Recirculation, EGR), glow plug preheating units, and pumps of all kinds (oil, fuel or water). Atmel's LIN devices can also be used for preference in the powertrain, because the SOI technology that it employs permits an IC operating temperature (TJ) of up to 200°C, thus completely covering the motor-compartment temperature range of up to 150°C.

Bus networking challenges

The development of robust and yet cost-effective bus systems is the basic prerequisite for success in the market. This is certainly true of the LIN bus system. And the volume forecasts for the coming years show a rapid upward trend.