Van tastic voyage: Toyota Sienna engineers crisscrossed the country to create a minivan that is designed for, built in and exclusive to the American market

Automotive Industries,  March, 2003  by Andrea Wielgat

• E-mail
• Print
• Link

It also helps keep weight down, something Toyota is deeply driven to do.

"As a company we are absolutely committed to beating the CAFE number every year," Williamsen says. "We've never paid a penalty. That's tough when you look at how many Lexus vehicles we're putting on the road and the content on them. We're real serious about weight"

Peace and Quiet

Toyota is also serious about noise. Besides all the traditional ways to cut noise including hard and soft foam, dash panel silencers and rear wheel-house sandwich panel, Toyota developed two new ways to help reduce noise inside the car.

With traditional carpet, the hard, rubber backing does not absorb sound like the rest of the carpet So Toyota developed a new process to allow the carpet to take in much more noise.

"After the carpet is made we run it through a special machine called a needle punch and it pokes holes in the carpet to let certain sounds--certain low frequencies in the cabin -- go through the carpet and the felt underneath the carpet can dampen the noise," Williamsen says. 'The needle punch carpet contributes to the quiet ride."

Toyota also selectively applies damping asphalt to the body shell using robotics. The robot applies the material only where it is needed, saving time, cost and weight compared to asphalt sheets.

Simplified Assembly

The Sienna is built at Toyota's plant in Princeton, Ind., alongside the Sequoia.

"The most impactful thing in production is simply the concept that we are building the unibody Sienna and the body-on-frame Sequoia on the same exact line," says Williamsen. "There might be a Sequoia frame and body drop and then the next thing that comes in is a Sienna powerplant on a subframe with MacPherson struts sticking out It's mind blowing to have that kind of flexibility car by car."

There is no setup, no changeover, not a moment of pause on the line. Toyota's flexible tooling transitions from one vehicle to another imperceptibly.

To help cut costs and manufacturing complexity, Toyota also developed modules and moved them off the assembly line and in one case outside the plant -- a simple adjustment that reaps huge dividends according to Jula.

Key off-line modules on the new Sienna include the instrument panel, door panel and the largest of the group, the headliner.

"Visualize for a moment how large the headliner in the Sienna must be," says Jula. "It's huge, it's cumbersome and it's really difficult to install."

It's even more complex since it includes side-curtain airbags, a roof mounted DVD system, multi-zone climate control air ducts and all the wiring harnesses. And as the complexity of all these things increases, so does the chance of poor fit-and-finish and ultimately increased NVH.

"The answer, we found, was modular assembly," Jula says.

So, Toyota moved the headliner and all of its components off the assembly line. Instead, Johnson Controls now assembles the headliner offsite at a facility less than 10 miles away. Instead of assembling the unit in stages and a small space, the headliner is laid on a bench. Individual component installation is now easier. The more precise method also allows for longer time for the adhesives to set while improving final fit-and-finish.