A fault-tolerant databus took a step toward broader automotive implementation this week, as NXP Semiconductors announced that it has rolled out a transceiver that complies with the FlexRay industry standard.

Known as the TJA1080A, the new transceiver is the first to pass the FlexRay Physical Layer Conformance Test, an industry standard for FlexRay products.

The product rollout is considered significant because the FlexRay communication system is believed by many to be a foundation for the future of automotive networking, especially in safety-critical systems. FlexRay technology has already been implemented on a BMW X5, for active suspension controls, and is believed to be in development in other chassis, powertrain and driver-assistance applications.

The TJA1080A is not NXP’s first FlexRay transceiver, but it is the first from any manufacturer to meet the industry standard.

“This guarantees interoperability with other transceivers,” says Rob Hoeben, NXP’s marketing manager for FlexRay. “It also guarantees it will work in any FlexRay implementation for any automotive manufacturer.”

The FlexRay standard calls for transceivers and other electronic products to meet certain parameters of timing and latency as they pass messages between electronic control units. Timing delays outside of a prescribed number of nanoseconds aren’t considered acceptable.

Meeting such parameters is considered extremely important because FlexRay was developed as a data bus and communication system for safety-critical automotive products. Although it was initially seen as a solution for brake-by-wire and steer-by-wire, automakers have begun using it for smart suspension systems and adaptive cruise control.

FlexRay fits the needs of such systems because its data messages are sent in a so-called “time-triggered” fashion, instead of the more conventional “event-triggered” way. Time-triggering ensures messages reach their destination because it uses flexible time division media access (FTDMA) slots for data. Thus, messages aren’t lost or forgotten. By employing the time-triggered design, FlexRay provides fault tolerance under all conditions, including the presence of a failed sensor, short circuit or transient software glitch.

Without time-triggered methods, creation of brake- and steer-by-wire systems would be nearly impossible, because engineers would be unable to ensure messages would reach their destinations without delay. As a result, brake and steering performance could be effected.

NXP engineers say FlexRay is gaining momentum with automakers. The FlexRay Consortium now includes more than 100 companies, including all major automakers.

Due to costs reasons, however, engineers don’t expect FlexRay to replace the industry’s popular CAN (controller area network) bus in the near future. For now, they say, CAN will continue to dominate in powertrain applications, while FlexRay picks up more safety-related applications.

“We are seeing projects popping up among customers who say, ‘We want to use FlexRay for other applications,’” Hoeben says. “It’s spreading a little faster than we initially expected.”

Emissions requirements haven’t just tightened up for cars and trucks. Off-road construction and agricultural equipment will soon face a new federal Clean Air standard that slashes allowable exhaust emissions by more than 90 percent. And that prospect has left the makers of off-road engines scrambling to meet deadlines that start as early as next year.

The standard, which the U.S. Environmental Protection Agency refers to as Tier 4, calls for 90 percent reductions to both particulate matter (PM) and nitrogen oxides (NOx). It will also reduce the sulfur levels in non-road diesel fuel by more than 99 percent. The standard phases in from 2008 to 2015.

From a public health standpoint, Tier 4 looks like a no-brainer. According to EPA estimates, it will, by 2030, prevent about 12,000 premature deaths, 8,900 hospitalizations, one million lost work days, 15,000 heart attacks, 6,000 children’s asthma-related emergency room visits, 280,000 cased of respiratory problems in children, 200,000 cases of asthma symptoms in children and 5.8 million days of restricted adult activity every year.

From an engineering standpoint, however, the rule requires some brainpower.

“Tier 4 may well be the biggest engineering challenge the industry has faced,” says Joe Loughrey, president and chief operating officer of Cummins Inc.

At last month’s Con Expo-Con/Agg show in Las Vegas, prominent engine makers like Cummins, John Deere Power Systems and Caterpillar displayed new engines or discussed their plans for meeting the emissions challenge.

Cummins, to take one example, rolled out a 6.7-§¤ next-generation engine that showcases some of the existing on-highway emissions reduction technologies that will be leveraged to reduce emissions off-road. Called the QSB6.7, the engine features a cooled exhaust gas recirculation (EGR), a high-pressure common rail (HPCR) fuel system, integrated particulate filter aftertreatment, a variable-geometry turbocharger and a brand-new air filtration system with integrated air flow management capabilities.

Together these technologies not only promise to reduce emissions but also improve performance a bit. According to Ric Kleine, vice president of Cummins’ off-highway business, the QSB6.7 engine offers 90 percent PM reduction and a 45 percent NOx reduction, yet increases power output from 275 hp for the previous generation to 300 hp — in essence giving the new engine a power output more typical of a larger displacement engine.

Other engine makers are taking similar steps to integrate emissions reduction technologies that have been necessary on the highways. Bill Haushalter, vice president of transportation business development at Custom Sensors & Technologies (CST), says he’s seen an across-the-board interest from the engine maker in the pressure sensors used for EGR and diesel particulate filter (DPR) applications. “The engine makers are all following the same path taken by heavy-duty on-road vehicles,” he says.

	The QSB6.7 engine from Cummins features emissions reduction technologies that help it meet a tough new federal standard.

Seventy years ago, Orson Welles terrified millions of Americans with a pre-Halloween radio broadcast pretending to announce a Martian invasion. In the next few months, we may find out if, in fact, Mars could ever support life as we know it. On May 25, a scientific lab landed on Mars and began the first in-depth exploration for the possible existence of life forms on the Red Planet.

The Phoenix Mars Mission is operated by the University of Arizona on a NASA contract, under the leadership of Principal Scientist Peter Smith, who has worked on several NASA projects through his role at the University’s Lunar and Planetary Lab.

The purpose of the mission is to follow up on the discovery by Mars orbiter Odyssey of the ice on the northern pole of Mars. In fact, there’s a lot of ice — enough to fill Lake Michigan twice over based on readings from an onboard neutron spectrometer.

“If you get to a place where there is ice, you wonder if over time, the climate could have changed to the point where that ice melted,” says Smith. “Now if you have liquid water, soil and sunlight, then you have a lot of the ingredients, but not all that can lead to a place where life can take a foothold.”

The key tasks of the Phoenix Mars Missions are to answer these questions:

• Can the Martian arctic support life?
• What is the history of water at the landing site?
• How is the Martian climate affected by polar dynamics?

The Lander uses a robotic shovel to dig into the Martian earth. Camera images from the end of the shovel are sent back to scientists on earth who determine where to strike.

“We feel very confident we can get through even very hard-packed soils,” says Smith. “The robot arm is very strong. If you were to brace your legs and hold on to that arm and try and stop it from moving, it would drag you.” Mission engineers feel the shovel can even handle ice that could have the consistency of granite. “We’ve put a power tool on the end of the arm that actually acts as a rasp and it spins and it throws pieces of ice chips inside of the back of our scoop, and we can deliver those to our instruments. So we are sure that we’ll get a sample of even the hardest materials,” says Smith. “Putting the spacecraft down on one of the colder parts of Mars is really something that has stressed our engineering team and so we’ve had to come up with a well-insulated container to hold our electronics, which only work down to certain temperatures, and then we put in heaters to keep those electronics above that temperature at all times.”

Temperatures in the polar zone of Mars, equivalent to northern Alaska, range from -140 to -60C in an atmosphere that is extremely dry. Special testing is required to determine materials’ fitness for those conditions. On the plus side, tests only had to determine fitness for a few uses, not thousands and thousands of cycles.

At the heart of the mission are the scientific experiments that are being conducted.

The Thermal and Evolved Gas Analyzer, or TEGA, is a combination of eight tiny high-temperature ovens coupled with a mass spectrometer. Contents are being analyzed after they’re baked. The ovens are about the size of an ink cartridge in a ballpoint pen. Scanning calorimetry shows transitions from solid to liquid to gas of captured Martian earth. Scientists can measure how much water vapor and carbon dioxide gases are given off and how much water-ice is present. And most intriguingly, what if, as Smith surmises, there may have been a warmer and wetter past? What minerals may have been formed at that time? And if organic volatiles are released, they will be measured.

TEGA was built by the University of Arizona and University of Texas at Dallas. One of the exotic materials used on TEGA is a proprietary titanium sheet from ATI Wah Chang, an Allegheny Technologies company. “ATI 425 titanium sheet was selected for major structural elements in the Phoenix Project Thermal Analyzer due to its good cold formability,” says Mike Williams, lead mechanical engineer for the TEGA team.

Studying Dissolved Salts

Like much of the equipment on the Phoenix Mars Mission, the Microscopy, Electrochemistry, and Conductivity Analyzer was originally conceived for a cancelled 2001 mission. Four wet chemistry labs are mixing soil with water in a container loaded with 20 electrochemical sensors. They’re looking for pH, dissolved oxygen and amounts of salts and minerals. MECA is being built by a team at the Jet Propulsion Lab., headed by Michael Hecht. Sam Kounaves, a chemistry professor at Tufts University, is a Phoenix co-investigator and the project leader for MECA’s four wet chemistry labs project.

“The solution in the beaker will dissolve salt in the soil,” says Jason Kapit, a mechanical undergraduate engineering student at Tufts University who worked on the project. “The dissolved salts in the soil will teach us about the history of water on Mars.”

The upper assembly of MECA consists of a sealed, fluoropolymer-coated, titanium leaching solution reservoir. Cast epoxy is used as a reaction vessel. Reaction chambers for future experiments will use Ultem polyetherimide.

One of the MECA instruments is a thermal and electrical conductivity probe consisting of three small spikes that are measuring  temperature and thermal properties of the soil. The spikes are also analyzing the electrical conductivity to indicate any transient wetness that might result from the excavation. Unfrozen water on Mars could exist in the form of thin, briny films on the surface of particles. The electrical conductivity measurement could confirm their presence. The probe was developed by Decagon Devices of Pullman, WA.

Also on board is a Meteorological Station, or MET, which is tracking weather on the ice cap until it is rendered useless by the onset of winter on Mars in November. It includes LIDAR, or Laser Imaging Detection and Ranging, which are counting  dust particles in the atmosphere. The team working on LIDAR includes the Canadian Space Agency, York University, the University of Alberta, Dalhousie University, the Finnish Meteorological Institute, Optech and the Geological Survey of Canada. It was built by MacDonald Dettwiler and Assoc. Ltd. of Richmond, B.C.

The other two major partners in the Phoenix Scout project are the Jet Propulsion Lab. (JPL), which is the project manager, and Lockheed Martin Space Systems (LMSS), which is the flight system manager.

One of the JPL functions is to provide interface to the Deep Space Network, sending command sequences and receiving data during the 10-month cruise to Mars. Lockheed Martin built the spacecraft in a project headed by Ed Sedlivery, who was also the chief engineer on the 2001 Mars Surveyor Lander, the mission that was canceled.

“The basic structure and most of the avionics are identical to the 2001 lander,” says Tim Gasparrini, deputy program manager at Lockheed Martin in charge of entry, descent and landing of the Phoenix Mission lander. “We made changes in some of the components and changed out some of the thermal protection systems and we made a number of changes to the flight software and some of the algorithms we use to fly the spacecraft.”

The lander weighs 772 lb and is about 7 ft tall and 18 ft long with the solar panels deployed. The science deck is about 5 ft in diameter. The lander uses a mono-propellant hydrazine system that is designed to decompose exothermically into hydrogen, nitrogen and ammonia. The test equipment takes into account the ammonia deposited on the surface by the lander. Use of airbags was never considered for this lander.

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The fundamental spacecraft structure is made of graphite-reinforced polycyanate composites. Two of the benefits of polycyanate matrices over materials such as epoxy are improved moisture absorption and outgassing properties. The result is fewer dimensional changes due to dry-out during orbit. Polycyanates are more resistant to micorcracking during thermal cycling, as well.

Aluminum and titanium are used for various fittings on the spacecraft. The primary adhesives used are based on epoxy and acrylic. “We use acrylic adhesives mainly for the multilayer insulation blankets on the outside of the spacecraft,” says Neal Tice, the chief mechanical engineer for the lander. “Blankets are also used on the ground. Acrylics are a very good adhesive for space-forming applications. It has a very broad temperature range.” External temperatures in space approach minus 220F. On the sun side, temperatures approach 250F. “That’s in a vacuum environment, so there is no convection,” adds Tice. Ablation temperatures on re-entry approach 3000F.

A proprietary thermal protective system developed by Lockheed Martin is made of room-temperature-vulcanizing (RTV) silicone rubber and other materials. The shield ablates during re-entry. The ablative shield burns away so heat can be carried away from the spacecraft.

There are two unique metal constructions used to absorb impact when the lander touches down on the granite-like ice permafrost surface. “In the legs of the lander, we use a cylindrical honeycomb crusher (made from aluminum) to absorb energy on landing,” says Gasparrini. “We also have annealed stainless-steel load limiters attached to the legs. I have one on my desk and it’s all bent over.” The parts were evaluated on special testing equipment developed by Lockheed Martin.

So, here it is 70 years after the Orson Welles radiocast and it’s not the Martians coming here looking for life; it’s us going to Mars.

In the most detailed explanation yet, Program Manager Pat Shanahan described the steps Boeing is taking toward the first flight and eventual deliveries of the new plane to customers. He left no doubt the biggest cause of the latest six-month delay and risk to the new schedule is relying on partners to build key components of the airplane.

“Where do I think risk is? The capability of the supply chain. That is the untested part of this production model,” he said, adding no significant technical issues remain other than what could be found in testing. “It’s just a matter of burning through the work.”

Shanahan’s detailed explanation in his characteristic monotone of what’s been done and what’s left seemed to placate financial analysts and the media. They've asked much tougher questions on previous update calls. The latest schedule, which Shanahan labeled “more conservative” was born out of a comprehensive analysis of the existing production schedule promised in January.

Shanahan’s remarks came just after Boeing announced a new six-month delay this morning in the first flight to fourth quarter this year and first delivery to September 2009. Boeing said deliveries next year will be “approximately 25” down from its previous forecast of 109 and the full production rate of 10 a month will not be achieved until 2012. Orders for the 787, according to CEO of Boeing Commercial Planes Scott Carson, stand at “892 from 61 or 62 commercial customers.”

Shanahan broke down the new schedule this way:

Stiffening spars in the wing box, which called for additional brackets and “simple parts” caused a two-month “deterioration” in the previous schedule. That pushed the critical first “power on” milestone from April to June because the “rework” caused a one-month delay as it fell “right in the middle of the critical path for wiring and systems installation.”

He also said Boeing will extend testing by two months, which should give the company breathing room for unforeseen problems that arise in testing. “If we do not need that time, we will not use it,” he said. Clearly with no margin for contingencies in previous schedules, Boeing got burned. Shanahan’s new schedule seems to fix that.

He also said much progress has been made and there would be no compromises in the “operational efficiencies” as designed. On large components Shanahan said the wings are almost ready, as is the fuselage.

“We will take the wings to the point of destruction. We’ve put the ultimate load on the stabilizers and fuselage,” he said. “We tested the composite test barrel to where we nearly broke the test fixture before we broke the barrel,” he said, adding there were “a few minor problems.”

Boeing still has 15 percent of the component testing to perform, which will be done by the end of Q2 culminating “in static and fatigue tests on the full-scale airframe in the next few months.” Shanahan said Boeing has yet to decide if it would destruction-test a full airplane. Also, planes 3 and 4 will enter final assembly before June 30, he said.

As for the mechanical and electronic systems, Shanahan said only the brake controls, in-flight entertainment, aspects of the power systems and maintenance functionality of the flight control remain to be tested. The airplane has 2,700 system elements and 900 component part numbers. The fastener shortage and software work blamed for causing delays last Fall have largely been resolved, he said.

“The 777 was service-ready five months after its first flight. The majority of the 787 will be service-ready four months before first flight,” he said. Only a “handful of open issues” remain for defining the certification flight tests, which will begin in the first quarter of 2009 using six test airplanes. The GE engines were certified on March 31 and the chief test pilot has been certified on both the GE and Rolls engines, he said. According to Shanahan, Boeing and the FAA have found a “path forward” to resolve lightning protection issues.

Finally, Shanahan addressed how the problem was found in the wing box spars.

“We had a finite element analysis error. It’s like building a house with nails except on an airplane you analyze every nail,” he said, referring to clips and fasteners in the wing box.

Several questions pertained to how deeply the delays will bite into the 892 orders, delay penalties paid to customers and financial problems experienced by some of Boeing’s key 787 suppliers. Carson and Shanahan declined to elaborate or said the issues would be addressed in Boeing’s quarterly results call on April 23. Last week, Boeing bought Vought Aircraft Industries’ interest in Global Aeronautica LLC, which has had problems delivering parts of the fuselage on time.

Rapid advances in adhesives technology will allow the design of significantly lighter cars and also enable use of thinner steels. Some new platforms are already employing the new approach with much broader gains expected soon.

Ford reduced the weight of the 2008 Ford Focus 3.7 lb through increased use of crash-durable structural adhesives in the upper body, says Shawn Morgans, Ford's body structure technical leader. “We have reduced spot welds,” Morgans told Design News. “The focus from here on will be to reduce the gauge of the steel.”

General Motors' engineers also have their eyes on the increased use of the brand-new super-bonders.

“It would be very nice to use crash-toughened adhesives extensively,” says Mark Verbrugge, the director for GM's Materials and Processes Lab., “and not have riv bonding, thermal joining, friction stir welding or anything else. That would help reduce weight. The fixturing in the plant is also problematic if you end up having to put in rivets or something else to make sure the structure stays put. What you would really like to have is an adhesive bond that fixtures and sets up immediately.”

New GM vehicles developed under the Epsilon and Delta banners, in Europe and Asia, respectively, will utilize newly developed crash-resistant adhesives. New Opels are also expected to use the advanced systems.

Use of structural adhesives for car bodies is most advanced in Europe where manufacturers are committed to reducing carbon dioxide emissions to a maximum of 120 g/km for all new passenger cars by 2012. Crash-stable adhesives are being used in the structures of new Mercedes and BMW models, for example.

Adhesive bonding in cars has a long history including the bonding of glass into the body flange. Bodies represent 25 percent of a car's weight and are key targets for weight savings. Until recent years, high-strength adhesives used in aircraft and other applications were not suitable for car bodies because they were brittle in crash situations, particularly at low temperatures. The technical breakthrough came with the development of a two-stage system that modifies impact resistance. A chemical reaction creates toughened particles and a flexibilizer in a process called synergistic rubber toughening. The toughened particles reduce fracturing and absorb energy. Soft particles, only a few nanometers in size, are uniformly distributed throughout the matrix before the curing of the adhesive.

Another significant technical advance makes crash-stable adhesives suited to conventional car production systems. They typically cure at temperatures around 356F, allowing the pre-treatment electrocoat process to cure the structure without a dedicated curing oven. The newest of the materials can be used in temperatures ranges from -40 to 176F.

The techniques advancing fastest today employ hybrid bonding. As Verbrugge points out, spot welding or some other conventional fastening system is required to provide initial strength. Another factor — simulations are limited in predicting the behavior of the very new crash-stable adhesives as part of a full vehicle test.

“Another area where we are seeing a lot of uptake is in high-strength steels,” says Chris Liddiard, a director of structural solutions for Henkel. “The steel doesn't yield very much so you tend to push that energy to the weld very quickly if you aren't careful.” Use of the new adhesives improves seam integrity by providing a dual-energy management system.

The big next-generation breakthroughs for structural adhesives will come when reliable predictions can be made of the bond's behavior on a car-size scale and faster-setting-up adhesives are developed. But rapid progress is under way, with implications for many types of mechanical design.

The Lotus Take

“Globally, the challenge for the automotive industry is to increase the fuel efficiency of vehicles, while improving safety, performance and maintaining affordability,” says Jason Rowe, chief mechanical engineer for Lotus. In a recent research report, Lowe writes: “One of the biggest recent advances in joining technologies is in the performance of structural adhesives.”

Lotus is using structural adhesives with mechanical fastening techniques on its VVA (versatile vehicle architecture) structure, introduced in 2005 that is made mostly of aluminum shapes. Self-piercing rivets are used in place of spot welding with flow-drill screws used for single-sided access on closed sections. Both hold the structure together during the bonding cure cycle and prevent adhesive joint peeling in a crash. Heat-cured structural adhesive is the main joining medium. The system is said to provide exceptional torsional stiffness.

“The combination of self-piercing rivets (SPR) and adhesives provides a joint with a far greater peel resistance than bonding alone and at least three times the strength of riveting alone,” says Rowe. “In addition, the SPRs allow de-jigging of the primary structure before the adhesive is cured, holding the geometry and dimensions without specialist fixturing through electrocoat.” The new approach was required because spot and MIG welding can degrade aluminum.

Lotus is using the VVA in its upcoming 2+2 sports car. Once part of GM, Lotus makes sports cars and operates as an engineering consultancy under the ownership of a Malaysian manufacturing company.

The first American vehicle to make extensive use of the new crash-durable adhesives was the Ford F-150 pickup truck, which received the highest crash-resistant rating in its class by the U.S. Insurance Institute for Highway Safety. It was also the first crash-resistant adhesive that didn't require heated pumps.

Examples of other new models making increased use of structural adhesives include:

• New models using the Delta and Epsilon platforms. One example is expected to be the 2009 Daewoo/Chevrolet compact sedan, although specific confirmation could not be made.

• Betamate 1496 is used on Audi A5 structural elements such as pillars, bottom construction and front walls. Dow Automotive officials say the new adhesives provide up to 25 percent improved body stiffness and up to 15 percent more energy uptake in a crash. Their durability improves the strength of bonded joints up to 1,000 times the break time versus spot welds and gap protection is also provided by the sealing characteristics of the adhesive.

• Dow developed a new grade for the BMW X5 front rails, front of the dash, shock towers and underbody. A plant in Michigan was modified to produce the material which is formulated to stay secured to the body structure during body wash, phosphate and e-coat baths. Other features are low viscosity, advanced processing characteristics and excellent corrosion resistance.

• The external panels of all six luggage doors of the new Domino from Italian coach builder IRISBUS are bonded to the aluminum body with Betamate 2096.

Use of the new materials isn't limited to high-end cars. Adhesives developers say they see high interest from Asian and Indian OEMs developing a new, inexpensive world car. Adhesives allow more process flexibility compared to welding systems.

A Few Caveats

Some challenges still face increased use of crash-resistant structural adhesives. One is the basic conservatism of design engineers, who are familiar with, and trust, conventional joining methods, particularly spot welding. Another is the lack of a program that can simulate the mechanical properties of the new materials on a large scale. The thin bond lines in the new adhesives require an extra-fine mesh that increases the number of finite elements beyond the capabilities of even high-performance computers. Experts are working with the Fraunhofer Institute for Mfg. and Applied Materials research to solve the problem.

There is also a need for adhesives with higher heat resistance that will allow use of the new materials close to the engine block. There will also be a push for adhesives that cure at lower temperatures, allowing OEMs to save on e-coat oven operations. Also look for grades with shorter cure times.

Use of adhesives is not interfering with auto recycling in Europe, according to Marc Van Den Biggelaar, global market manager, Body Structure Solutions for Dow Automotive. Shredded body structures are bundled and sold to remelters, such as the electric arc furnaces used in the steel industry. “There's no special treatment for the adhesives. They burn off at higher temperatures,” says Van Den Biggelaar.

Recycling could become problematic, however, when steel is bonded to aluminum or recycling, one of the advantages of the adhesives systems.

Electric steering systems offer fuel efficiency advantages and reduced CO₂ emissions over hydraulic power steering systems that run nonstop. The compact Mazda 2's electric motors only respond when they're needed, saving pricey fuel. TRW Automotive provides software and plenty of hardware, including the electronic control unit, steering angle sensors and the column drive motor. Electric power steering systems communicate over the vehicle's CANbus, so data can be shared with other systems to improve overall driving comfort.

Those who need big SUVs for towing or other reasons can now benefit from the fuel savings provided by hybrid drive trains. General Motors' full-size Chevy Tahoe Hybrid and GMC Yukon Hybrid both have a two-mode hybrid system that can cut fuel consumption by as much as 50 percent in city driving. Freescale's 32-bit Power Architecture controls the power inverter module that's the basis of the hybrid system. The chips help assure smooth transitions during transitions from gasoline to electric power. The two-mode system, developed in conjunction with Chrysler, Mercedes and BMW, sometimes operates with both electric and gasoline engines to improve performance and economy.