The small car is alive and well in Europe. Without exception, European carmakers (together with Ford Motor Co. and General Motors Corp. European offshoots) are fast shifting to super-light small cars to meet increasing fuel costs, emission standards, parking restrictions and the possibility - make that probability - of limitations on car usage in major cities.

For all of its problems, it seems certain there will be more cars like the Mercedes-Benz A-class. Volkswagen AG's Audi division already has previewed the aluminium AL2 and promises that this will be a true 3L car when it goes on sale in 2000. That's not three liters of engine capacity, but fuel economy. Three liters per 100 km, or 83.4 miles per U.S. gallon, has become the benchmark target for fuel consumption in Europe. And the figure is through the combined fuel cycle, not just an urban cycle, or at a comparatively slow steady speed.

What's driving the demand for significantly more economical cars is costly European fuel prices. German, French and English drivers pay three to four times as much for fuel as their U.S. counterparts. That means up to $80 to fill the tank of a medium-sized car.

To achieve the "3L" fuel objective, Europe's carma-kers are turning to a new breed of diesel engine using the so-called common-rail principle. Fiat SpA was the first to introduce the technology, in both 4- and 5-cyl. engines in the Alfa Romeo 156, and claims its Elasis research center invented the idea. With help from Mercedes-Benz AG, Fiat then decided to turn to Robert Bosch AG, which acquired the common-rail patents to put the concept into production.

In general terms, Fiat claims the common-rail diesel uses 20% less fuel, yet delivers a 12% performance boost over conventional turbodiesel engines.

Common rail is a system of electronic injectors whose output can be controlled more accurately than conventional injectors. The heart of the system is a five-jet injector coupled to a highly sensitive electro-hydraulic valve and a new vane-type hydraulic pump. It's geared to half crank speed, which also has its output electronically governed to deliver pressures from 250 to 1,300 bar (3,625 to 18,850 psi). Demand varies according to an electronic map.

Conventional cam-type injector pumps top out at 700 to 800 bar (10,150 to 11,600 psi) and their pressure is geared to crank speed. Common rail refers to a log-like induction manifold that communally supplies the injectors at high pressure.

Within weeks of the Alfa launch, Mercedes introduced its new 220D powered by a new 2.2L 4-cyl. engine. Compared to the non-turbo engine it replaces, the new engine has exactly twice the torque and 24% more power. By 2000, Mercedes predicts its entire diesel engine range will be common rail, with new 2.7L 5-cyl. and 3.2L 6-cyl. in-line engines (modular versions of the 4-cyl.) and a 4L V-8.

The Fiat Group engines have now spread to Fiat and Lancia models. Renault SA already has announced one direct-injection (DI) diesel and plans to use another in its new Clio, due to be launched at the Geneva show this month, where Peugeot SA will unveil its new common-rail engines in a variety of Peugeot and Citroen models.

Chrysler Corp. also has announced plans for similar engines, while VW, which grabbed the lead with conventional DI diesels in the mid-'90s, is expected to announce production of com-rail engines later this year.

The secret to achieving the 3L/100 km fuel consumption lies with combining the common-rail technology with lightweight cars. The first of many is likely to be Audi's A2, the production version of the concept AL2 first shown at the 1997 Frankfurt motor show. The show car weighs 1,785 lbs. (811 kg) - a conventional steel-bodied Mercedes A-class is 2,248 lbs. (1021 kg) - but Audi says the production car will weigh just 1,650 lbs. (750 kg), courtesy of its aluminium spaceframe, with alloy panel construction.

Compared to the aluminum Audi A8, the A2's spaceframe beams are welded together instead of using cast nodes, and new "internal reshaping" techniques allow the beams to be more closely matched in strength to their requirements, further cutting weight.

The A2 follows the A-class in using a sandwich double floor, strong sills and a high seating position for good crash safety. On the concept AL2, Audi showed off a 3-cyl., 15-valve 1.2L DI gasoline engine, another area of development, but it will be a new common-rail 3-cyl. diesel that delivers "3L" fuel consumption.

The trouble for the world's carmakers is that Europe's inexorable move to smaller, lighter and far more fuel-efficient vehicles is at odds with what's selling in North America and even, though to a lesser extent, in Japan.

Platform sharing was the industry-wide buzz word in 1997. Those keenest to embrace and promote the advantages of this once common practice are those carmakers (VW, Ford and GM are the most obvious) who over decades allowed individual markets, product planners and engineers to override a rational approach to car building and create similar-sized, but wholly different cars. Ford's European Scorpio, Australia's Falcon and America's Taurus are totally different cars that share few if any components, though their customer base is very similar.

The logical extension of a common platform philosophy is world cars. GM, Ford and VW watched with growing envy as the Japanese sold essentially the same cars in every market of the world: Think Corolla, Accord, Civic, 626 and Pulsar. Of course, there was a time when the VW Beetle, Ford Model A and GM T-car were also universal in their appeal and engineering.

America's move to - by Euro-standards- gas-guzzling "light trucks" that take 45% of the market, and Japan's fast-shifting trend toward hot station wagons and mini-SUVs and MPVs, reduces the benefits of an intelligent, cost-saving platform policy, at least as seen by European-based carmakers.

VW's move to only four platforms won't become fact until early next century - when VW replaces the joint Ford-VW MPV with a new model built over Passat underpinnings and the Polo-based successor to the Skoda Octavia is launched - but the versatility of the idea is cleverly illustrated by the variety of models built over VW's so-called B/C platform.

Manufacturing flexibility and the ability to reduce the number of design and engineering hard points means VW can adjust the wheelbase of the B/C between the Audi A4's 102.9 ins. (261 cm), the Passat's 106.5 ins. (271 cm) and the A6's 108.6 ins. (276 cm). And it can modify the tracks to suit wider bodies all without changing the basic suspension and while using the same lines.

Even the 1999 V8-powered Passat Plus retains the same basic dimensions as the Audi A6. VW plans two competitors for the S-class Mercedes Benz, one from VW and the other from Audi on its D platform. Both will use a new W12 engine, as well as V-8s, and the same transmission and suspension, but the Audi sticks to the alloy spaceframe construction of the A8, while the VW version's body will be made of steel.

On its small AOO/AO platform - wheelbases from 91.7 ins. (233 cm) to 94.5 ins. (240 cm) - VW plans to build the next Brazilian VW Gol, the Polo, the new SEAT Ibiza and Cordoba, the new Skoda Felicia, SEAT Arosa, the VW EA420 Lupino and VW's even smaller "3L" economy car. There also will be a new coupe and sports car, and even a small SUV. VW says each car will share 70% of all components.

To avoid unnecessary duplication and sidestep the errors of GM's look-alike models from the '80s, VW intends to promote the brand image of its four marques against rivals. Specifically, SEAT against Alfa Romeo, Skoda opposed to Volvo, VW takes on Mercedes-Benz, and Audi battles BMW. VW believes that giving its Skoda and SEAT models styling that reflects their national character will prevent remaking the same cars.

By 2003, says VW Chairman Ferdinand Piech, the group's range will have grown from today's 38 models to 51 models, despite cutting the number of platforms from the 16 of three years ago to just four.

Ford, too, is attempting to integrate its new-model development on a global basis, a keystone to its Ford 2000 restructuring. Ford is a couple of years behind VW in terms of platform policy cars reaching the showrooms, but even so, the philosophy of developing a growing number of niche models from mainstream platforms is now beginning.

The European Fiesta has bred the Puma coupe, the trendy Ka hatch, the Brazilian Courier pickup truck and still another model to come. None is sold in the U.S. because they're too small to be popular and justify the expense, says Ford. On the other hand, the European Mondeo was developed alongside the U.S. Contour/Mystique and has now spawned the new Cougar coupe.

Will Boddie, recently appointed director of Ford's Small and Medium Car Vehicle Center, based almost equally in both Britain and Germany, defends Ford's global platform policy. "Our research shows that the basic functional characteristics, market to market, are very similar," says Boddie. "So what's the point of having three entirely different C-class cars: the European Escort, Mazda 323 and American Escort?

"Why duplicate the engineering work when a single platform can do the same job, and that doesn't mean they have to be the same car," he says. "If you want a robust, efficient platform that can be adopted to each market, then by using our resources in Germany, Japan and the UK we wind up with a platform that's better engineered and takes advantage of real economies of scale.

"From an engineering standpoint the focus is now on the customer," says Mr. Boddie. "Our previous organizational structure was functional-based, the people who made the car didn't concentrate on the product. They were what I call brokers."

What are the compromises involved in developing a common platform in countries with vastly different cultures?

"In absolute terms, separate platforms for individual markets does give you ultimate flexibility, while common platforms does limit the flexibility somewhat," Mr. Boddie says. "On the other hand, if you decide you need separate platforms for different markets, you can never afford the same enginering resources and wind up with a platform that doesn't have the same engineering quality, tooling efficiency or refinement. So it's not a great compromise."

He says in the long term, "Mazda will share our platforms, but there will always be product-development capacity at Mazda. They will do product for us and we will do product for them. But if Ford wants to do a model for Japan, then there will always be a Japanese involvement to ensure that you have a local influence. That might mean you change the body shape or use different fabrics in the interior, but the economies of scale means you can find the best solution to suit local customers.

"It's only through the use of global platforms that you are able to achieve the right leverage of your product-development resources," says Mr. Boddie.

GM takes a similar approach, but it divides the world into its North American Operations and the rest of the globe, although inevitably there will be an increasing amount of product-sharing between the two organizations. So sensitive is the issue of the way GM's future product programs are divided up that German unions made the subject a crucial part of its recent round of negotiations.

Concerns that GM intended to cut back on product developed at its Russelsheim, Germany, International Technical Development Center (ITDC) were only put to rest when, in late January, GM signed a pact that says the ITDC in Russelsheim will maintain development responsibility for theCorsa, Astra, Vectra and Omega model lines.

Louis R. Hughes, president of General Motors International, has the task of turning GM into a global carmaker, rather than a U.S. company with various secondary, international operations. GM's Opel AG operation is the key to the process, but even small divisions, such as Holdens in Australia, will still play important roles.

GM's Delta, Gamma and Epsilon programs, the internal code-names for the new Astra, Corsa and Vectra/Omega, are going to become truly international, for the intention is to sell effectively the same mainstream versions in all markets. While the new Sigma program (or GWRD, for Global World Rear Drive) is being initiated from GM Holden's in Melbourne, Australia, GM's European operation also is tweaking the Vectra for Brazil and for Saturn in the U.S.

Says Mr. Hughes: "It's the largest expansion in our company's history."

Small cars sure, but when you're playing with world markets the numbers are huge. GM's international operations are half again as big as all of Renault.