A decade later, Kappel can still recall his frustration. "That was the reward for successful development," he says. Luckily for Siemens, Kappel, now 48, was not one to give up easily. Although he had developed the fuel injector for gasoline engines, he decided to push it as a product for diesel engines -- and stumbled on two colleagues who were completing a study on what new technologies Siemens could provide to that niche. With their help, Kappel kept his project alive.
Today, auto makers from Mazda Motor Corp. to Jaguar Cars Ltd. () are using Kappel's injector in their diesel models. Siemens has delivered more than 10 million of the injectors since production began five years ago. The draw: The technology, known as the piezo injector valve, boosts performance while reducing fuel consumption up to 20% and cutting carbon dioxide emissions. "We are very satisfied with these injectors," says Fr?d?ric Dubois, an engineer in charge of fuel injection technology at Peugeot, which uses them in its compact 206 diesel and other models.
For Siemens, the new injector is the type of innovation that vindicates the $6.3 billion, or 7% of sales, that the electronics and engineering giant spends annually on research and development. Thanks to Kappel's work, Siemens' VDO Automotive () unit now owns a sizable chunk of the market for diesel fuel-injectors, which had been dominated by rivals such as Stuttgart-based Robert Bosch.
Developing the product was a slog, though, and a case study in how even deep-pocketed corporations find it difficult to bring in-house innovations to market. Kappel, who studied applied physics at the University of M?nster, started his career as a researcher in ink-jet printers at Siemens. But in 1990 the company asked him to switch his attention from spraying ink to better ways of spraying gasoline. At first it was lonely work. The people in adjoining labs worked in other fields, Kappel recalls, and his superiors were at a Siemens facility in Newport News, Va. "I didn't have very many colleagues to talk to," he says.
His task was to make use of a phenomenon known as the piezoelectric effect (the prefix piezo comes from the Greek for press). As far back as the 1880s researchers knew materials such as quartz crystals and even sugar give off a charge when subjected to pressure. They also expand instantaneously when zapped with an electric charge. Kappel's idea was that a piezo-driven injector made of a ceramic material would activate a valve more quickly and spray fuel more precisely than a conventional electromagnet-driven injector -- so cars would consume less gas and produce lower emissions.
The principle was straightforward enough, but building the product was immensely complex. Piezo materials react differently at different temperatures. And they don't expand enough to push open a valve. So Kappel combined the piezo switch with a hydraulic system that amplified the mechanical effect. Kappel says he filed 180 patents in the course of developing the injector.HIGH PRESSURE
Expect the market for Kappel's product to grow as European regulators demand lower carbon dioxide emissions and better fuel economy. That's a major motivation for BMW, which is expected to use piezo-driven gasoline injectors in some of its models beginning in 2006. Not surprisingly, Bosch has introduced its own piezo-based fuel injector and is providing formidable competition. While neither company will give out sales figures, the market is certainly worth hundreds of millions of dollars.
Adapting piezo injectors for gasoline engines, however, is still a challenge. The high-pressure injectors lead to more nitrogen oxide emissions than conventional injectors. Engines using them thus need a more costly catalytic converter to eliminate the nitrogen oxide. And to achieve full performance piezo injectors require sulfur-free gasoline, a fuel that is widely available only in Europe. That means it will be several years before the technology takes hold in the U.S. and Asia.
Kappel, who three years ago was crowned "Inventor of the Year" at Siemens, is looking to develop other products based on the piezo phenomenon. A stripped-down auto door in his lab provides a clue to one project. Kappel is working on a power window system that, with the help of a piezo sensor, would reverse direction if a child sticks his hand in a closing window. The system works but so far is too costly to produce. He's not about to throw in the towel, though. Innovation, Kappel says, "depends on people who believe in their inventions even when they encounter resistance, and keep fighting." As a reminder, he still has that 1995 rejection letter. By Jack Ewing in Frankfurt, with bureau reports