Multi-Purpose Motorheads

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.

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.” 

 

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.”

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. ?

 

BMW’s Bi-Turbo Six

Since debuting in 1923, the in-line 6-cylinder has had a special place at BMW. In 2005 alone, more than 53%, or 600,000 units, of the brand’s global volume was powered by the venerable powerplant. So what’s an automaker to do with its most successful mill? How about spice it up a bit? That’s exactly the purpose behind the new high-pressure injection biturbo 3-liter in-line six BMW presented at the Geneva Motor Show. Producing 306 hp and 295 lb.-ft. of torque, the new engine has the capability to accelerate a 3-Series sedan from 0-62 mph a half-second faster than its normally-aspirated sibling, and cut acceleration from 50-75 mph by 1.9 seconds. The engine uses the same aluminum bedplate construction with magnesium shell as the normally aspirated inline sixes, which helps make the 3.0-liter biturbo 158 lb. lighter than a normally aspirated 4.0-liter V8 of similar output. It also uses the latest piezo-injector technology to reduce fuel consumption by 10%, and places the injectors centrally between the valves. In this position, the injector is able to distribute fuel in a conical burst, ensuring smooth fuel distribution within the combustion chamber. BMW decided to use two smaller turbochargers—each supplying three cylinders with compressed air—instead of just one big turbocharger for all six cylinders to reduce lag and fuel consumption. The turbochargers are constructed from a special heat-resistant steel designed to withstand temperatures of up to 1,920ºF, which eliminates the need for extra air flow to produce a cooling effect during high operating loads. The lower inertia of the smaller turbos also greatly reduces turbo lag, and makes it possible to more closely tailor the turbocharger output to engine demand.

“For a long time turbo was linked to a considerable increase in fuel consumption and we deliberately decided to set this technology aside for a while, considering rising fuel prices. But now, thanks to the distinctive features of the in-line biturbo six-cylinder engine, supercharging is again meeting BMW’s requirements,” says Burkhard Goeschel, BMW’s Management Board member responsible for product development.

Goeschel also imparted that BMW decided against radical changes to its in-line six configuration because the engine already provides distinct benefits, particularly in its compact dimensions and tendency to produce minimal noise, vibration and harshness drawbacks: “The in-line is clearly the one that runs the most smoothly and vibrates the least.” Watch for the new 3-liter biturbo to make its debut in the 3-Series and Z4 coupe later this year.—KMK

 

Airing Diesel Emissions

“Our clean diesel rules will reduce air pollution from diesel engines by about 90 percent, and reduce the sulfur content of diesel fuel by more than 95 percent,” President George W. Bush, Virginia BioDiesel Refinery, May 2005.

The one thing the President failed to mention is how automakers will meet the tough new Tier 2 Bin 5 diesel emission standards. Debate has been raging in product development groups throughout the industry on which technology is the most effective at meeting the new requirements, while remaining cost-effective and user-friendly. Some automakers have already banked on urea-based aftertreatment and Selective Catalytic Reduction converters to treat the exhaust before it is released from the tailpipe. The major problem with this solution is the necessity to replenish the urea. Automakers plan to rely on service technicians to check and refill the urea each time a vehicle returns for routine maintenance. But what happens when the urea isn’t refilled and vehicles do not meet the required emission standards? The U.S. Environmental Protection Agency has yet to warm up to the urea solution because once the urea runs out the NOx treatment stops. The complexities of building an infrastructure to support urea or another afterteatment solution prompted Delphi Corp. (www.delphi.com) to devise a new diesel emission reformer that uses air to convert diesel fuel into a hydrogen-rich gas reformate, produced through a catalytic partial-oxidation process. Since the reformate (which is injected directly in the exhaust system) is rich in hydrogen and carbon monoxide, harmful emissions are reduced and the gas can be used to regenerate the NOx absorbers and particulate filter. The key benefit to OEs is the elimination of urea and other additives, according to John Botti, executive director of fuel cells and reformers for Delphi’s Energy & Chassis unit. “With our solution everything is on-board and you don’t need a different infrastructure.” Botti hinted the technology can be used to improve emission performance in gasoline engines with direct injection systems, reducing NOx emissions in lean-burning operations. Delphi envisions the reformer gaining traction in the medium- and heavy-duty truck market, along with light-truck and SUV applications, while conventional piezo injection technologies will likely be more than sufficient for smaller passenger cars to meet the new emission standards. “Most of the conventional passenger cars should be able to avoid the urea or the reformers because of their small displacement, but when you start to get into pickup trucks and heavy passenger cars, that is not the same song,” said Botti. The lack of a urea tank would provide a weight savings and the reduction in precious metals would reduce overall cost to OEs. The major problem in Delphi’s plan is timing. With 2010 as a target date, the reformer will be nearly two years behind the required standards, which could leave an entire range of vehicles out in the cold and tons of business off the table for the troubled supplier. Botti said there are no plans to speed up the development of the reformer before 2010, adding Delphi wants to make sure the technology is reliable before it begins production. “We are working hard on durability demonstrations. We need to run the normal hot and cold cycle and we want to make sure the technology comes out in a very reliable way.” Delphi has been testing the reformer on six commercial trucks and Botti said all have exceeded the Tier 2 Bin 5 requirements.–KMK