Wild Horses, Engines and Fuel Economy

What do these three have in common? To Delphi’s Paul Van Heyningen, there is a connecting thread. 

“Picture in your mind, all of those documentaries where you see a herd of stallions galloping across the Great Plains, full throttle,” said Van Heyningen, Delphi’s chief engineer for valve train products. “That’s what an engine wants to do! When we want that horse to go slowly through its productive use, we pull back on the reins. Similarly in an engine, you are basically putting a control valve in the airflow, up in front of the engine.”

The concept of having two valve settings to control the amount of air fed to an engine – what the industry calls variable valve engine controls – has been around since the 1980s. But an inventive twist from Delphi has made them affordable, durable, reliable and applicable to 80 percent of the engines in the marketplace.

Nissan and Alfa-Romeo are credited with developing variable valve timing 30 years ago. Honda introduced variable valve actuation in the mid-1990s, which improved fuel economy by using a device that was mounted to the rocker arm shaft. It was easier to implement but more expensive and limited to Honda’s unique “type 3” engine.

It was only after a decade of research that Delphi found a way to make this technology more widespread.

“You have an overhead camshaft, a valve, another pivot location and an arm that articulates, sandwiched between those three parts,” Van Heyningen said.  “So the challenge became, now I have this part, in space, in the engine -- and now I need to make that part variable.”

Delphi’s “two-step” device works on “type 2” engines (also known as roller-finger-follower, valve train designs) and is precursor for future engine software controls that will help the auto industry make the next leap in fuel efficiency. 

That’s exactly what Delphi did for one automaker, beginning in 2015. The two-step valve saved 4 percent in fuel economy on a 3.6-liter engine. Other car companies are incorporating the Delphi solution in future engine designs that will be sold by 2019.

Two-step also enabled Delphi to help introduce another engine control called Dynamic Skip Fire. Later this year, Delphi will showcase a VW Passat that gets 20 percent better fuel economy, thanks in part to two-step valves, Dynamic Skip Fire and 48-volt, mild hybrid technology.