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Denso's developmental CO2-based air conditioning system. A shift from R-134a is good for the environment—and challenging for the engineers.

No, this is not a real Holden. Rather, it is an image displayed by Vis Concept from EDS. Stereoscopic glasses would allow a three-dimensional experience.

Trends, Developments & Tools: A Sampling From This Year's SAE Congress

Richard Smith, director, Climate Control Engineering, Denso International America, Inc., says that serious work is underway at Denso in developing a more environmentally benign air-conditioning system, one that will make use of CO2 in place of the R-134a refrigerant.

COOL IT.

Richard Smith, director, Climate Control Engineering, Denso International America, Inc., says that serious work is underway at Denso in developing a more environmentally benign air-conditioning system, one that will make use of CO2 in place of the R-134a refrigerant. As you may recall, R-134a was used as a replacement for R-12, an ozone-depleting refrigerant. The first automaker to make a fleet-wide change to R-134a was, according to Smith, Toyota, a Denso customer, in 1994. However, Smith points out, "While the conversion to R-134a was a significant step, basically one refrigerant was replaced by another, albeit a much safer one, using fundamentally the same system components. But if that was a step, converting to a CO2 system could well prove to be one of those ‘giant leaps.'"

The global warming potential value of CO2 is just 1/1,300 of R-134a. That is the up side. The tough side is that the pressures that are involved in creating a CO2 refrigerant system are seven to 10 times greater than with the other material. Consequently, this is a system that is more challenging to design and build. Yet there are some other advantages. For example, Denso is building CO2-based hot-water heating systems (based on a heat-pump) for Japanese domestic use. These water-heating systems went into production in May 2001. They've determined that compared to a natural gas heating system, there is a 30% reduction in power consumption. Smith admits, of course, that there is a significant difference between developing stationary devices and mobile units.

Smith says, "Denso has developed system components, including a hermetic-type electric compressor, a gas cooler, a unique accumulator tank that includes an internal heat exchanger, and an evaporator." He suggests that, because of the design of the accumulator tank, the installation of the system in a vehicle is fairly straightforward. Denso's goal is to develop a system that is the same size and weight as a conventional air-conditioning system.

It's worth noting that this developmentis of more than passing interest as Denso has the world's number-one market share in climate control systems.

 

CONNECT IT.

One of the problems with moving to CO2 from R-134a for automotive air conditioning systems is that the molecules of the former are much smaller than those of the latter. Consequently, conventional materials for climate control systems such as rubber for tubing just don't do the trick because the CO2 can leak out. What's more, there is the whole issue of the CO2 being under significantly greater pressure.

The people at Witzenmann USA (Warren, MI) have a solution in the form of a metal hose. This is a stainless steel corrugated hose with end fittings that are laser-welded in place. Because there are pressure pulsations involved in the air-conditioning system's cycling, there is a danger that the corrugated hose could lengthen and widen. So in order to accommodate that, there is a braided steel jacket around the inner tube. And to make sure that any mechanical wear between the two is minimal, there is a silicon coating between the tube and the braiding.

Apparently, this is going to be used on a 2004 European vehicle—on a system that is being developed by a company other than Denso.

 

COMPOSITE.

According to Dick McKechnie, automotive business director, Composite Solutions Business, Owens Corning, the market for composite materials in Europe right now is "great". . .and he admits that one of the reasons why this is so is because production volumes tend to be smaller than they are in North America, on the order of 60,000 units. However, he also says that vehicles tend to be increasing in size in Europe—he cites the Volkswagen Golf, for example—which contributes to automakers looking for ways to at least stabilize the mass of their vehicles. Which results in the use of composites.

One vehicle that is employing a composite front-end carrier is the Mini-Cooper. It, McKechnie explains, is made with the company's StaMax P, a thermoplastic composite developed by Owens Corning and DSM Automotive Polymers, with the former providing the glass-fiber know-how and the latter the thermoplastic material and part-production knowledge. This is a long fiber material that can be used in existing injection molding equipment. One of the key advantages of the application for the Mini is that a single part consolidates what would otherwise be numerous metal parts. It is also said to be lighter than the alternative, and has overall lower systems costs.

McKechnie says that one area of focus at the company is getting a better handle on process technologies, which will facilitate the greater use of the composite materials. For example, Owens Corning is working with Stewart Automotive Research (SAR) on a process wherein fiberglass strips are used with SAR's proprietary tooling technology to create composite springs and other structures in a cycle time that's half of what would ordinarily be required.

 

RECYCLE IT.

One of the issues related to the use of composites in automotive applications is the issue of recycling. DuPont Engineering Polymers is working on a new, closed-loop recycling process that can be used to reprocess glass-reinforced nylon into the same types of products they were prior to recycling: As in a radiator end tank back into a radiator end tank. DuPont worked with Denso on this specific process. A facility to perform the process has been developed with Fielding Chemical Technologies, in Mississauga, Ontario. Denso is providing washed, post-consumer end tanks. Feedstock is also being provided by North America material suppliers.

Called "DuPont Composite Recycle Technology," this proprietary chemical process can handle various nylon polymer and fibers, as well as reinforcements including glass or minerals. "The process reclaims polymer with a minimal loss of content for improved economics," says Dr. William Y. Hsu, vp, DuPont Engineering Polymers, Global Technology.

The economic issue is one of great concern. And not necessarily for the reason that you might think. Hsu says that a few years ago, DuPont developed a process called Petretec, which is used to recycle polyester-based products, like soda bottles. "But after we commercialized the technology, we realized the market perceived the cost would be less than virgin polyester," he notes. "So we subsidized the program. After several years of red ink, we had to shut down and discontinue Petretec. Even though the technology has positive social and environmental impact, without economic viability, Petretec was not sustainable."

They're hoping that as Composite Recycle Technology is developed, it will have the viability they need.

 

SEE IT.

For years, robot companies have been talking about vision systems for robots. When it comes to applications not of a quality control nature (i.e., checking for absence/presence in a fixtured environment), the results have been less than astounding.

Braintech (North Vancouver, British Columbia) has developed a single-camera vision system that's based on a software development system the company is calling "eVisionFactory," or eVF. Apparently, the big difference between what Braintech is offering today and what was available in the past is the contemporary microprocessor that has the capability to handle the data necessary to make the adjustments to the robot's servo. Essentially, the CCD camera, which is mounted on the robot's end effector, sends information to the controller that calculates the position of the part in reference to a "golden" image stored in memory. This comparison results in the ability to send offsets to the robot arm so that work can be done. According to a company spokesman, the single camera provides an accuracy of 0.1 mm.

One of the early applications is robotic drilling of holes in blow-molded plastic fuel tanks produced by TI Automotive. One of the difficulties of this application is that due to the nature of the molding process, locations can shift slightly.

Braintech is working with companies including ABB Flexible Automation and Marubeni to proliferate this technology throughout robotic applications.

 

SHARE IT.

In the introduction of a paper that Mark Gisi, then at the Software Technology Lab, Hewlett-Packard Laboratories, wrote with Cristiano Sacchi of the CAD Group, CNR-ITIA, it states, "It is becoming increasingly common for manufacturing design teams to be composed of members belonging to the same organization, yet located in geographically different places. This has significantly increased the need for better support of synchronous communication among team members collaborating over a design. Unfortunately, there is a considerable technological gap in the support for collaborative, synchronously communicating mechanical CAD systems."

That was written in 1994. While much has changed since then, the demand for collaboration over designs hasn't changed much. Of course, now there are members who work for suppliers, as well. But the need for collaboration is critical.

One thing that has changed is that Gisi and some colleagues spun off from HP Labs and formed Actify, Inc. in 1996. (He's the vp of Business Development; Dr. Sacchi is vp of Engineering.) Gisi says their objective is to create something analogous to the Adobe system (i.e., those .pdf files that are often attached to documents) for CAD systems. One of his points is that there are far more people in any organization involved in product development than have access to or familiarity with CAD systems. So they've developed their easy-to-use solution, called "SpinFire." This product permits 3D design viewing on PCs in a manner that is sufficiently simple for non-engineers/non-designers to use. The software permits designs to be measured, marked up and shared. Because Actify has partnered with the major CAD vendors, it is pretty much CAD-agnostic. Although the "real" CAD data is sent (e.g., via the Internet), much of the underlying data is taken away so that the file sizes aren't so large as to bring the typical PC to its knees.

 

VIEW IT.

Sometimes it is useful to see a vehicle—the whole vehicle. The vehicle in its full dimensional, surface-reflective glory. But while it is still a digital object, not something made of metal, plastic, glass, and rubber. So to facilitate this, EDS has announced Vis Concept 3.0, which provides what's called a "1:1 scale immersive virtual reality environment."

To be sure, this package can be used to drive the virtual-reality CAVE environments. But it also permits using desktop computers (which means, of course, that the photo-realistic image of interest is not a full-size car or truck, but rather something that can fit on the screen). To see the images in all of their faux-reality, it is necessary to put on a pair of stereo glasses. And it should be noted that this software has more application than just vehicle and component design: it is possible to model a factory so that layouts can be optimized and training can be enhanced.

The software is CAD neutral (a direct model [.jt] common data interface is used. It operates on Silicon Graphics, Hewlett-Packard and NT platforms.

One of the cited benefits is that this information can be networked via the Internet (serious bandwidth is required for big models) so that people can collaborate, say, on a vehicle design. Other benefits include a reduction in the dependence on physical prototypes, the ability to speed design refinement, and the ability to see things that otherwise might be missed with a model (as the image can be manipulated rather extensively on the screen in ways that physics prohibits).

 

MEASURE IT.

Accelerometers for such applications as security, active suspension, headlight angle control, tilt sensing, rollover, and telematics. . .that are 15 to 50% lower in cost than competing products, yet no less functional? That's what the folks from MEMSIC, Inc. (Andover, MA) say that they offer in the company's line-up of integrated-circuit (IC)-based accelerometers. Instead of using moving parts like capacitive-based sensors (that, say, use tiny springs), these utilize micro electric mechanical systems (MEMS) technology. Essentially, there is a small cavity in the IC. This cavity is filled with nitrogen (or, in the case of a new ultra-low-noise version, another gas, which is, apparently, still a competitive secret). The gas is heated. As there is a tilt, a bubble in the gas is detected. There are no moving parts. One of the reasons why the accelerometer is less expensive is because it is based on a standard, submicron CMOS (complementary metal oxide semiconductor) technology.

 

CONNECT IT.

While companies are considering rivets for assembling body panels, an alternative that doesn't require predrilling of a hole is being offered by AKH, Inc. It's called the "fas-ner." Essentially, there is a bowl-fed press; press tonnage ranges from 5 to 30 tons. There is an hour-glass shaped fastener, made of aluminum or high-carbon steel, that is as long as the thickness of the two pieces of material to be joined; the fasteners range in size from 0.075 to 0.360 in. The materials to be joined are positioned within a dieset. The lower die shears the material, and the slug forced down by the fastener, which works as a punch, is ejected. Finally, coining rings in the top and bottom dies come into play to force the joined material around the concave section of the fastener. Because the fastener's length is equal to the thickness of the joined material, the surfaces are flush top and bottom, so no additional finishing is required. In addition to which, it is possible to use the process on prepainted or precoated materials while using fasteners of the same color.

 

WHAT DO DESIGNERS & ENGINEERS THINK?

For the eighth year in a row, DuPont Automotive has surveyed automotive engineers and designers to find out what issues they're dealing with. So in the category of challenges, the following responses were tabulated by the Automotive Consulting Group:

  • Cost reduction: 30%
  • Fuel Economy: 17%
  • Emissions regulations: 14%
  • Safety regulations: 12%
  • Designability: 10%

There are a couple of interesting things about the 2002 results versus 2001. One is that in 2001, cost reduction was cited as a concern by 36% of the respondents. That is the only category where there is a drop, and the size is a non-trivial one. Does this mean that (1) designers and engineers are not particularly concerned about cost (unlikely) or (2) that "cost reduction" has now become what "quality" became a few years ago, the proverbial "price of admission"—something that is thought to be a requirement and therefore not a concern per se?

The second interesting thing: in 2001, only 1% noted designability as being a concern. Even though it is last on the list in 2002, the size of increase in importance shows it to be a growing concern, to say the least.