Multi-Purpose Motorheads

Automotive Design

In less than 40 years, Weber Automotive has evolved into a multi-national powertrain component supplier. Next on its agenda: the design, development, and supply of complete engines for automotive and recreational use.

Weber Automotive (Markdorf, Germany; www.weber-motor.de) has grown from a small business started in the chicken coop of Albert Weber’s father’s farm in 1969 to a multinational supplier of engine blocks, crankshafts, cylinder heads, connecting rods, and gearbox cases with facilities in Germany, Hungary, the United States, and China. Yet it has gone beyond being a component supplier, at least as regards development. In partnership with Swiss-auto Wenko (www.swissauto.com), it developed a four-stroke parallel twin engine (i.e. two vertical cylinders parallel to each other coupled with balance shafts to damp the primary vibrations). This MPE (Multi-Purpose Engine) architecture also has spawned a family of 70? V4s ranging from 1.6 to 2.0 liters, built from a pair of even-firing twins on a common crankshaft. It is this engine family that may put Weber in the automotive engine supply business in China.

Looking more like a racing motor than an engine for passenger cars, Weber Automotive’s MPE V4 is not only more compact and lighter than production engines of the same displacement, it has a future in marine applications and may find a home in China.

In the MPE design, the chain drive for the overhead cams is between the leading and trailing cylinders instead of at the end of the cams. This means a single head design can be used on the V4, and customers have the opportunity to place the intake in the front or back of the twin cylinder version without incurring any extra cost. For the larger displacement (800-cc) twin and smaller displacement (1.6-liter) V4, the pistons and connecting rods are largely the same, as are the four valves per cylinder, shimmed roller rocker arms, 88-mm bore, and optional intake and exhaust cam phasing. (The 2.0-liter V4 has the same bore, but a longer stroke.) A bank angle of 70? was chosen to minimize the V4’s width so that it could comfortably fit in place of an inline four-cylinder, or in the engine bay of a sport boat or other recreational vehicle. The V4 is built around an aluminum bedplate, and the block and heads are made of the same material.

“This compromise on the bank angle,” says Eberhard Wizgall, v.p. and CTO of Weber Automotive, “means it’s not too wide to fit or too narrow to be able to handle all of the liquids within the V of the engine. Like the twin, we integrated all of the auxiliaries, and the oil and water pumps are driven by auxiliary shafts.” A fully dressed naturally aspirated V4 weighs less than 100 kg, while a turbocharged version tips the scales at 120 kg. According to Wizgall, this compares to an average of 135 kg for a naturally aspirated 2.0-liter inline four-cylinder automotive engine. In addition, the 2.0-liter V4 has a box volume of 380 mm x 515 mm x 551 mm, reductions of–respectively–28%, 6.4%, and 15%. “Our engine,” claims Weber Automotive CEO Christian Weber, “is the most compact and lightest 2.0-liter, and has the best performance-to-exterior dimensions in the industry.”

Is 2 > 4?

As gas prices increase, so does the talk about putting smaller, more powerful engines under the hood of future vehicles. To see what they could add to this debate, the engineers at Weber Automotive pulled the 1.3-liter inline four from a Ford Ka, and replaced it with their MPE750 parallel twin tuned for automotive use. While it may sound like they were trying to build a well-equipped golf cart, in reality the two-cylinder not only weighed less and took up less room, it had better fuel economy and significantly better output—torque and horsepower—than the standard Ford engine. As a result, it accelerated from a standing start to 62 mph 1.6 seconds quicker than the standard car, and posted better in-gear acceleration times.

That claim extends to the high-performance turbocharged marine variant that boasts 300 hp and 251 lb-ft of torque. This engine is designed to replace boat engines based around American V8s, and its uneven firing order even gives it a mini-V8 sound. “We have roughly the same consumption rate at 60 mph,” says Wizgall, “but at cruising speed [20 to 40 mph] it’s effectively half that of a V8.” This isn’t the first marine motor from Weber. The MPE I2–complete with cooling and drive system so it could be plugged into place on the assembly line–was supplied to Polaris for their personal watercraft in 135-hp form. Doing the same for larger sport boats with the V4 would not be much of a stretch. However, it is the automotive market that holds the most promise, especially since the marine version is still under development.

With most automakers designing and developing their own engines, the market for the Weber V4 would seem to be limited, and that is true, for the most part, in mature markets. Though Weber Automotive has seen some interest in the engine from established car makers, it is in China that the most interest has been shown. Weber will open a plant there in 2008, and it has been designed to grow with the demands on the company. “Strategically,” says Christian Weber, “we see the day when we will be asked to supply complete engines to automakers, and not just those in China. Especially since we don’t carry the cost structure they do. Already, we are seeing production of the blocks, cranks and cylinder heads starting to move to outside suppliers like us, and–while engine assembly is something else entirely–niche production of complete engines is well within our capabilities today.”

Before the company decided to exit the market, Weber’s parallel twin MPE engine was best known as the motive force behind personal watercraft from Polaris. Though it also ended up under the hood of a Ford Ka (see chart), the engine originally was intended for a SMART-like city car built by Matra (shown).

The company’s growth has been explosive since its founding in 1969, and global competition has caused many automakers to outsource component production. There are those within the industry who claim complete engine design and production is next. If this proves to be true, more will be heard from Weber Automotive in the coming years. ?