Murata
Toyota Pursues the Elusive 'Triple WOW'

Built on an all-new platform, the 2002 Toyota Camry is quieter and roomier while being both more fuel efficient and more powerful. It was developed in far less time than its predecessor, to new standards that should ensure even higher manufacturing quality. So, the folks at Toyota are pretty satisfied with their handiwork.

But they won’t truly be happy unless the average customer’s response to the new Camry is a heartfelt “WOW.”

The Camry has always been a left-brain car. Rational, reasonable, sound and solid, people didn’t buy it for its 0-to-60 time, but for its zero down time. Chided as a bloodless transportation appliance, the Camry nevertheless occupies enough American garages to have made it the best selling passenger car in the U.S. for four straight years. Kosaku Yamada, the affable chief engineer of Toyota’s “K” platform vehicles (which include Camry, Avalon, Sienna, Highlander and the Lexus ES 300) puts it this way, “There is a ‘Camry-ness’ that is familiar and reassuring. It is a product equity that has been cultivated and built upon over the last decade. And it has been the key to Camry’s success as the top-selling car in America.”

The problem is that for too many potential customers that reassuring “Camry-ness” is spelled B-O-R-I-N-G.

Yamada recognized that Camry’s trusty strengths were also the source of its greatest weakness. So he charged his team with an overall project target for the 2002 model he called the “Triple Wow.” A customer should say, “Wow,” on first seeing the car, again upon sitting in it, and finally, should be wowed by the driving experience. Though initially befuddled by their boss’ queer nomenclature, the team eventually got the picture and developed a Camry that is sleeker and more elegant than the current edition, and is significantly more likely to stir the desire of someone who has never considered the sedan in the past. But, this being Toyota, even the pursuit of emotion was done in a methodical way.

Getting Horizontal
“The process is slow and expensive. And up until this project, it was our standard operating procedure.” That’s Dana Hargitt, Camry project leader at the Toyota Technical Center in Ann Arbor, describing the traditional vertical development process at Toyota. For Camry, Toyota embraced a more horizontal development flow that emphasized simultaneous engineering and brought disciplines together at the initial drawing stages to analyze all aspects of the vehicle at once. Their goal was to eliminate all engineering changes after production drawings were released.

With the help of massive computing firepower (Toyota in Japan owns the most powerful supercomputer outside of a government institution), digital simulation increased markedly and tooling costs were slashed. The number of prototypes needed was reduced by 65%. “In the development of the previous Camry we could only calculate vibration data for 20 Hz or less,” explains Yamada, “At a higher hertz level it did not match with the actual vehicle, so we needed prototypes to analyze those vibrations. But with the current Camry, we could simulate vibrations up to around 100 Hz. Because of that we could eliminate a significant number of prototypes.” Yamada adds, “The previous Camry’s development time from design styling approval to Job One was around 36 months, this time is was around 26 months.”

Shaving 10 months off of the development time of a brand-new model has obvious advantages in grabbing sales from the competition. But in the case of the Camry, introduction intervals are set well in advance, so a shorter development does not mean a new Camry will hit the market any sooner. The benefit to Camry and other existing models is the additional engineering attention paid to small details that enhance the feeling of quality. Hargitt’s team at TTC were able to simulate more parts than on any previous model (in fact, the new Camry is the most extensively simulated vehicle Toyota has ever produced)–things like overforce calculations on cup holders and fuel lids.

Lower NVH, Better Ergonomics
Camry has always been the NVH bogey for its competitors, and the engineers at Toyota intend to keep it that way. Some of the NVH countermeasures 
that the folks at Ford and Honda will find when they dismantle the new Camry include:

  • A very rigid body sporting 4,300 spot welds (compared to the 3,000 Toyota found on an unnamed American competitor).
  • Curved floor panels that reduce booming noise.
  • Stiffeners across the rear parcel tray, under the rear seats and in the spare tire well to prevent road noise from entering the cabin.
  • A new principal inertia axis mounting engine layout with mounts along the longitudinal centerline of the engine that re-direct vertical engine vibration in a horizontal direction less likely to be felt in the cabin.
  • The use of structural adhesives in the wheelhouse, dash and doors in concert with spot welds to increase body rigidity.
  • The use of foam in the A, B and C pillars to reduce wind noise.

What won’t show up in a Camry teardown are the stringent ergonomic standards used to design assembly processes. The new Camry team was tasked with implementing a new Toyota global standard. They did this by utilizing digital assembly software that uses animated workers to simulate each process and identify potential problems. More than 300 processes were analyzed using both the software and input from line workers in the factory. Motions were classified as “red”, “yellow” or “green” based on difficulty. Engineers found that many of the original processes were rated “red” and had to be changed.

Further investigation was done through off-line pilot builds at TTC’s lab in Plymouth, Michigan, that brought line workers up from Toyota Motor Manufacturing Kentucky (TMMK). Hargitt says, “This is the first time we have ever analyzed, modified and confirmed assembly line buildability in this depth, and this early, away from the assembly line.” The result was the elimination of all of the processes deemed “red” and a large reduction of those flagged as “yellow”–making the new Camry a lot easier to build than the old one. Yamada simply says, “Easy to assemble means good quality.”

De-Automation
“We’re trying to make it lighter, cheaper, simpler, accessible to repair, quick to replace. We want to get to where team members can do a lot of the work on the equipment,” explains Gary Convis, president of TMMK, about the New Body Concept Line that was installed to build the Camry. Huge, heavy jigs and hard tooling have been replaced with comparatively light and agile electric robots, and unwieldy assembly automation has been exchanged with simpler, human-guided machines. Convis cites the machine that tightens many of the underbody bolts as a prime example of the new manufacturing approach. The old machine was a “huge train” that was fully automated and difficult to maintain. Every part had to be in just the right place in order for it to work properly. The new machine is much lighter and is guided into place by an assembly worker, who then activates it and moves on to other tasks.

The New Body Concept idea has been applied to most of Toyota’s plants in Japan and will eventually become a global standard, but TMMK is the first plant in the U.S. to implement it. The concept’s heavy use of teachable robots means a great increase in flexibility and speed for TMMK. (Though Convis tells AD&P that TMMK will probably stick with building only the Camry platform since volumes are high and the logistics duplication involved in building two different platforms is inefficient.) And since the Camry’s all-new platform will be the base for both the next Sienna and the next Avalon, TMMK’s other products, future model changes should be faster and smoother–by design.

 

NVH reduction applications include:

  • A new balance shaft drive system that helps to negate the secondary harmonic typical of four-cylinder engines through the use of polymer resin gears reinforced with aramid.
  • A plastic intake manifold that has three additional resonating chambers and is tuned to eliminate noise.
  • A two-way exhaust control system that reduces booming noise by 10 dB at low rpm.
  • Accessories (A/C compressor, power steering pump) mounted directly to the block for a vibration reduction of 9 dB.

 

Camry’s New Four Cylinder Engine

It is worth contemplating in this time when massive V8-powered SUVs prowl every suburban street, that the bread-and-butter engine for America’s best-selling car is a four banger. And when Toyota’s engineers set out to design the first all-new Camry platform since 1992, they included a complete re-design of their workhorse four- cylinder base engine.

Building on the strengths of the previous powerplant, they focused on reducing NVH, trimming weight and increasing fuel efficiency and power.

engine

An aluminum die-cast two-piece block replaces the iron block on the previous engine and goes a long way toward the huge 19% reduction in dressed engine weight (112 kg from 138 kg) that was achieved.

Similarly, horsepower is up by 15% and torque by 10%. And even with these improvements, fuel efficiency got slightly better (24/32 mpg vs. 23/30).