Winds of change are blowing through the auto industry at gale force. Unfortunately, those blustery conditions will buffet Detroit for the rest of this year. In fact, there’s a good chance that volatile conditions will persist throughout this decade.
The auto industry is in the midst of a huge transformation. When the winds of change finally subside, products and production processes will be dramatically different than traditional models and methods.
Today’s climate is similar to the conditions that existed 100 years ago, when steam power gave way to the internal combustion engine, open-top wood carriages succumbed to enclosed steel bodies and piece-rate production was replaced by mass production.
"There’s a massive transformation currently underway in the auto industry," says Dr. David Cole, director of the Center for Automotive Research at the Altarum Institute (CAR, Ann Arbor, MI). "It’s a period of very high turbulence and activity. As a result, the industry will undergo a dramatic reduction in product development time and a significant reduction in cost."
As the first decade of the 21st century unfolds, engineers are scrambling to implement flexible manufacturing systems that bring vehicles to market faster. At the same time, evolving technologies, such as lightweight materials, fuel cells, drive-by-wire and 42-volt electrical systems, present both new opportunities and unprecedented challenges for manufacturing engineers.
Lightweight MaterialsAutomakers are attempting to lower vehicle weight to meet regulatory requirements for reduced emissions. Aluminum, lightweight steel and thermoplastic play an increasingly important role in the material content of automobiles. For instance, the typical vehicle contains 274 pounds of aluminum and 250 pounds of plastic.
But, nontraditional materials, such as carbon fiber and magnesium, are becoming more prevalent in the auto industry, especially as new processing techniques and joining methods are developed.
According to Keronite Ltd. (Cambridge, UK), the use of magnesium in the average car is expected to increase from 4 kilograms per vehicle today to at least 65 kilograms by 2020. Magnesium is the lightest of all structural materials, and it has the highest strength-to-weight ratio. It is two-thirds the density of aluminum. Magnesium also allows small draft angles, which enables cheap and rapid machining of auto parts.
Traditionally, magnesium has been used to produce custom auto parts, such as high-performance wheels. However, the high cost of magnesium is expected to drop as Australian, Canadian and Chinese producers boost ingot and alloy output. As a result, the lightweight material will soon be used in a wide variety of mass-produced auto parts, such as structural components.
Ford Motor Co. (Dearborn, MI) plans to use a large magnesium casting at the front end of its 2004 model F-150 pickup truck in place of the current multipiece pressed and welded steel assembly. It will support several components including radiator fans, headlamps and direction indicators. The use of a single magnesium part instead of 15 welded stampings will save significant weight and simplify assembly.
General Motors Corp. (Detroit) is one of the leading proponents of magnesium auto parts, which offer advantages over other lightweight materials, such as aluminum and plastic. Magnesium can be die-cast and offers weight-saving and productivity advantages over aluminum, and strength and shape-retention benefits over plastic.
GM is planning to use floor-mounted magnesium shift towers and console covers in its pickups, vans and sport utility vehicles. One-piece magnesium shift towers would offer numerous advantages over steel units, such as parts consolidation, the elimination of welding or mechanical assembly operations, and improved noise dampening.
Many 2004 GM models will feature cast magnesium instrument panel support beams. For instance, midsize vehicles such as the Chevy Malibu and Pontiac Grand Am will sport magnesium beams. In fact, GM plans to use at least 900,000 of the lightweight beams per year, which will require approximately 20 million pounds of magnesium.
Also, GM plans to use magnesium frames in retractable hardtop roofs for a line of convertible models that it will launch in 2005. Many engineers favor automatic retractable hardtops over soft-top convertibles because hard metal roofs seal out noise better, provide better protection against break-ins, and are more durable. Each roof will employ two magnesium structural castings—a front frame and a rear frame. Demand for convertibles is expected to grow as part of the public’s increasing demand for niche vehicles.
Carbon fiber has traditionally been used to build race cars, but the material will soon be showing up in more and more production vehicles. In fact, a carbon fiber-reinforced plastic roof will be featured on a new two-door luxury sports car that BMW AG (Munich, Germany) expects to launch this year. The center console and inner door panels also will be made of carbon fiber-reinforced plastic, as will a few external components, such as the rear spoiler. The M3 CSL models will be built in low volume and sold mostly in Europe, where weight reduction is considered more important than in North America.
Researchers at Cranfield University (Bedford, UK) recently developed a carbon fiber concept car that weighs half as much as its steel-bodied equivalent. The body panels and space frame chassis of the Aerostable Carbon Car are made from the lightweight material. The researchers claim that tooling costs could be cut by 95 percent because carbon fiber molds are much cheaper than traditional tooling.
The vehicle’s chassis does not use traditional bonded or welded joints. Instead, the frame is held together by a series of nodes. The frame is made from braided fiber tubes, which are snaked through the nodes in a vacuum mold. This is then sealed and the resin is infused into the tube as it is drawn around the mold by the vacuum.
While nontraditional materials, such as carbon fiber and magnesium, have been gaining ground, "steel is anything but dead," says Stan Ream, automotive market leader at the Edison Welding Institute (EWI, Columbus, OH). "Light weight is nice, but cost is king. All things being equal, the auto industry will choose the lowest-cost solution." Ream claims that advanced high-strength steel will continue to be popul
Fuel CellsDespite the sluggish economy, many OEMs and suppliers are investing millions of dollars in fuel cell development. A recent study conducted by Principia Partners (Exton, PA) predicts production of fuel cells will grow at rates exceeding 40 percent per year over the next decade. If that rapid growth continues, the market for fuel cells will reach $20 billion by 2010.
Fuel cells are electrochemical devices that convert the chemical energy of a fuel directly into electrical energy in a continuous process. They have a high efficiency factor and, depending on the fuel used, produce little or no harmful emissions. For example, fuel cells operating on hydrogen and oxygen emit nothing but pure water vapor.
Fuel cells promise a possible end to the automobile’s traditional reliance upon petroleum-based fuels, with vehicle performance comparable to the internal combustion engine. In addition, fuel cells provide a virtually silent propulsion system.
There are four basic types of fuel cells: molten carbonate, phosphoric acid, proton exchange membrane and solid oxide. Proton exchange membranes (PEM) are the favored fuel cell technology for vehicular applications. They operate at low temperature, have high power density and can quickly vary output.
The heart of a PEM fuel cell is the membrane electrode assembly where hydrogen and oxygen are combined to form water and create electricity and heat. Individual membrane electrode assemblies are stacked to boost voltage. For instance, the fuel cell stack in GM’s experimental HydroGen3 vehicle consists of 200 interconnected individual cells.
To produce a fuel cell, catalyst-coated membranes are sandwiched between pairs of electrodes made from a conductive sheet material to form units called membrane-electrode assemblies. They are sandwiched between molded flat plates with mazelike channels in both sides.
Hydrogen is delivered to one side of the membrane where it is separated into electrons and ions. The membrane allows ions to pass through but it blocks electrons from passing. The electrons must pass through an electric circuit to get to the other side of the membrane, where they combine with the ions and oxygen to form water.
"Technology based on hydrogen really holds the promise for a future that can eliminate many of the emission concerns that we have today, as well as providing energy that can be renewed," claims Larry Burns, GM vice president of research, development and planning. "We are making outstanding progress in our fuel cell technology.
"Over the last four years, we’ve decreased the size and weight of our fuel-cell stack for a given power by a factor of 10 and achieved a tenfold reduction in cost," adds Burns. "We are driving to have compelling and affordable fuel cell powered vehicles on the road by the end of the decade."
Despite such optimism, a recent CAR study predicts fuel cells will account for only 1 percent of the U.S. market by 2012, because many substantial barriers remain. Brett Smith, a senior industry analyst, believes the cost of fuel cells and consumers’ reluctance to accept this increased cost will limit widescale acceptance of the technology.
"While industry may be able to meet the technical challenges of developing a commercially viable fuel cell…many of the basic elements of a hydrogen infrastructure are still uncertain, such as the delivery and onboard storage of hydrogen," explains Smith.
"Cost will be a severe barrier to the development of advanced power technologies, and fuel cells still have complexity and durability issues," notes Smith. He predicts that gasoline will continue to be a relatively inexpensive energy source.
Another big challenge that must be addressed is mass production. For instance, welding procedures and specifications need to be developed, because fuel cells use a wide variety of high-temperature alloys and large quantities of tubing. "The fuel cell itself is small, but it has lots of components that support it," notes EWI’s Ream.
"Most development efforts so far have been devoted to the chemistry and physics of fuel cells," adds Ream. "Now, people are starting to address manufacturing costs. Many fuel cells haven’t been designed for manufacturability. There are too many different fuel cell designs out there." Ream says numerous manufacturing issues need to be addressed, such as incompatible materials, temperature limits and thermal cycling, plus weight and size challenges.
"Fuel cells are likely to first achieve commercial viability for application in distributed power, industrial facilities and micropower," says CAR’s Smith. "Most current business cases for fuel cells are built upon the assumption that fuel cells for stationary applications will be viable long before the technology is ready for transportation use." Fuel cells will see widescale residential and commercial use first, which will eventually push the cost down to make the technology affordable for automotive applications.
But, observers admit that fuel cells are not a fad. They expect the technology will gain wider acceptance and more publicity every year. For example, the City of Los Angeles recently made headlines by becoming the first U.S. retail customer for a fuel cell car, the Honda FCX. The vehicle has been certified by the U.S. Environmental Protection Agency and the California Air Resources Board as a zero emission vehicle.
The FCX uses hydrogen supplied to a fuel cell stack to generate electricity and power its electric motor. With a maximum output of 80 hp and 201 ft-lb of torque, acceleration is similar to a Honda Civic. The FCX has a range of up to 220 miles and seating for four people. Los Angeles city employees will use five of the vehicles for car pool applications.
Honda plans to lease 30 fuel cell cars in California and Japan during the next 3 years. The company currently has no plans, however, for mass-market sales of fuel cell vehicles.
DaimlerChrysler (Auburn Hills, MI) plans to deploy a fleet of 60 fuel cell powered vehicles for testing in Europe, North America and Southeast Asia this year. The vehicle is a modified Mercedes A-Class car that accelerates from 0 to 60 mph in 16 seconds and can achieve a top speed of 87 mph.
Drive-By-WireThe mechanical linkages and hydraulic actuators that traditionally control automotive braking and steering systems will soon go the way of kerosene lanterns, rumble seats and hood ornaments. They will be replaced with drive-by-wire systems, such as brake-by-wire and steer-by-wire.
A steering wheel attached to mechanical linkages will no longer do the actual turning. Instead, it will send an electronic command for the wheels to turn. By-wire technology uses a highly organized network of wires, sensors, controllers and actuators to control "mechanical" functions.
"At the heart of the by-wire system are smart electromechanical actuating units, which convert the driver’s commands from electronic signals to motion," says Tom Johnstone, president of SKF Automotive (Plymouth, MI). "The by-wire system also provides dynamic feedback to the driver via electronic signals."
Throttle-by-wire systems are already used in some cars, such as the Audi TT. Brake-by-wire and steer-by-wire are expected to become widespread by the end of this decade.
"Everything from designing vehicles, sourcing components, logistics and inventory management to packaging and producing cars will be transformed by x-by-wire technologies," predicts Sarwant Singh, European automotive program manager at Frost & Sullivan Inc. (Fort Worth, TX). "The technology will accelerate the pace of growth in electronics in vehicles and curb the use of hydraulic and mechanical components."
Through modular design and elimination of hardware, x-by-wire technology will benefit automakers. Advantages include:
- Increased modularity. Fully functional by-wire modules will reduce assembly time and cost.
- Improved driver interface. The elimination of mechanical connections to the steering column will give engineers more flexibility in designing the driver interface with regard to location, type, feel and performance.
- Added flexibility. Vehicle designers will have more flexibility in the placement of hardware under the hood and in the interior to support alternative powertrains, enhance styling and improve interior functionality.
- Lead-time reduction. Assemblers will be able to use a laptop computer to perform soft-tuning capabilities and install custom options, instead of manually adjusting mechanical components.
"Steer-by-wire systems will boost safety and security, add to steering comfort and convenience, reduce production costs, boost productivity and give flexibility in designing and developing cars," says Singh, "providing opportunities to redesign cockpits and crumple zones, and the possibility of using joysticks. Most importantly, these systems will provide the vital link with driver assistance systems, including functions such as automatic parking assistance and lane control."
By eliminating the traditional steering column, steer-by-wire also promises to provide benefits in terms of crashworthiness, noise and vibration. "Steer-by-wire will be the enabler for fully integrated vehicle stability control systems, for collision avoidance systems and for autonomous driving," predicts Dieter Fehlings, engineering director for European steering operations at TRW Inc. (Cleveland).
"Coupled with the introduction of brake-by-wire systems, the design of the chassis will be greatly simplified," adds Fehlings. "Ultimately, there will be four equal corner modules that will be significantly lighter and easier to fit." This should lead to four-wheel-drive vehicles with fuel cell powered electric traction motors and independent steering at each "corner" of the car. However, Fehlings says the challenge for this technology is defining the fault-tolerant electrical architecture with internal redundancies that will enable the system.
Singh believes there will be a transition technology before the widespread emergence of x-by-wire systems. For example, the first steer-by-wire systems to appear on the market will probably have both steering columns and hydraulics. Singh predicts the first commercial electro-hydraulic steering system will be launched in 2005. The emergence of true steer-by-wire systems, which eliminate the traditional steering column, will occur around 2008.
42-Volt ArchitectureThe success of drive-by-wire technology depends on the ability of engineers to develop a more robust and reliable power supply system. Starting this year, automakers are slowly converting from the traditional 12/14-volt electrical standard to a new 36/42-volt architecture. The dramatic voltage increase is necessary to support power-hungry vehicles, improve overall fuel efficiency and reduce emissions.
According to Joerg Dittmer, a senior industry analyst with the automotive unit of Frost & Sullivan, 42-volt electrical systems will provide numerous benefits to automakers. For instance, the technology will allow additional onboard electrical applications and environmental friendliness. "These features make them attractive to auto manufacturers as they strive to deliver greater comfort and convenience to consumers," says Dittmer.
"Adoption of the 42-volt standard will unleash changes that will impact vehicles over many years as automakers realize more and more possibilities," adds Dittmer. "This represents both a threat and an opportunity to suppliers of electronic, electrical, mechanical and hydraulic components and systems. For example, steer-by-wire and brake-by-wire systems will challenge traditional mechanical and hydraulic systems. Insulating and housing materials made of plastic will have to have greater thermal and electrical durability than they do today.
"All major suppliers of starters, alternators and batteries are developing products for 42-volt vehicles because they cannot afford to be left behind when this technology catches on," claims Dittmer. "Additionally, suppliers of electronic equipment, power steering systems, brake systems, wire harnesses, connectors and many other components are working to meet the challenges ahead."
Dittmer says the need to initially retain two electrical systems—14 volt and 42 volt—will pose a challenge and be an added expense. But, he believes that benefits such as better fuel economy "are likely to cause automakers to spread 42-volt technology across their vehicle lines more quickly, especially once costs of components begin to come down."
Vehicle of Tomorrow?General Motors recently unveiled the world’s first drivable vehicle to combine lightweight material, fuel cells, drive-by-wire technology and a 42-volt electrical system. The Hy-wire concept provides a glimpse of what the vehicle of tomorrow may look like.
All propulsion and control systems are contained within an 11-inch-thick skateboard-like chassis, maximizing the interior space for five occupants and their cargo. There is no engine to see over and no pedals to operate. A single module called the "driver control unit" can be set to either a left- or right-hand driving position. It is attached to a horizontal bar that stretches across the full width of the vehicle for extreme flexibility. The driver control unit allows steering, braking and other vehicle systems to be controlled electronically rather than mechanically.
Because there is no engine compartment, the vehicle is very open from front to rear. For instance, there is no B-pillar between the front and rear doors. Drivers and passengers have greatly enhanced legroom. "The most dramatic view of this car may be from the driver’s seat, with a floor-to-ceiling view," says Ed Welburn, executive director of GM design for body-on-frame architectures. "It’s like being in my living room looking out my picture window."
The driver controls and operates the Hy-wire like an aircraft pilot via two handgrips arranged vertically on the control module. Drivers have the option to brake and accelerate with either the right or left hand. The driver accelerates by gently twisting either handgrip and brakes by squeezing the brake actuator also located on the handgrips. The handgrips glide up and down for steering.
Welburn says the driver operates the brakes very intuitively by automatically tightening the handgrips in a braking situation. Squeezing either the left or right hand grip slows the vehicle by way of grip sensors that determine how much hand pressure the driver exerts and transmit a signal that applies the brakes. The electrically actuated system works with conventional brake calipers, but responds faster.
A single docking port provides the electrical connection between the all-aluminum chassis and the fiberglass body. There are 10 mechanical body attachment linkages.
The fuel cell stack, which produces a continuously available power of 94 kilowatts, is installed in the back of the chassis. An electric motor drives the front wheels and is installed transversely between them. Three cylindrical hydrogen storage tanks are located centrally in the chassis.
"We are really serious about putting the technology contained in Hy-wire into production by 2010," claims Larry Burns. "Someday, Hy-wire could be displayed in a museum side-by-side with the first horseless carriages of Carl Benz or Gottlieb Daimler, or next to Henry Ford’s Model T."