Ford 3.5-liter EcoBoost V-6 twin-turbo engine revealed

Press Release

PUMP IT UP: ECOBOOST TWIN TURBOS PACK POWER TO GIVE V-6 ENGINES V-8 PERFORMANCE FEEL

* Twin turbochargers harness exhaust gas to pump V-8 power out of the smaller-displacement EcoBoost^TM V-6 engine. This technology - in conjunction with direct fuel injection - allows EcoBoost to punch above its size in terms of power and responsiveness
* EcoBoost engine has been engineered with such refinement that the driver never notices the turbocharger operation. Sophisticated electronic controls balance boost and torque levels to give the driver the feeling of continuous torque delivery, without turbo "whines" and "whooshes" that characterized some previous-generation turbo engines
* The EcoBoost turbo system runs at very high temperature, up to 950 degrees Celsius (1,740 degrees Fahrenheit). An air-to-air intercooler is used to cool the compressed intake air before it enters the combustion chamber, and water cooling protects the internal turbo bearings in the high-temperature operating environment

The "boost" of Ford's new EcoBoost engine technology comes from two small devices the size of an orange but with appeal that's far larger for fans of fuel-efficient performance.

They are turbochargers, which harness exhaust gas to pump more power out of a smaller-displacement engine. The new 3.5-liter EcoBoost V-6 engine uses twin turbochargers - in conjunction with direct fuel injection - to punch above its size in terms of power and responsiveness. It produces the horsepower and torque of a 4.6-liter, normally aspirated V-8 while delivering the fuel efficiency of a normally aspirated V-6 engine.
As an example, the 2010 EcoBoost Flex boasts segment-leading fuel economy among full-size performance crossovers with 22 mpg highway and 18 mpg combined, demonstrating Ford's commitment to deliver top fuel economy in each new vehicle.

Twin Honeywell GT15 turbos are fitted to each EcoBoost V-6, one for each bank of the vee. Exhaust gas flowing through the turbocharger spins a turbine wheel at very high speed - approximately 170,000 rpm - which drives a compressor turbine on the clean air side of the turbo. This fan effect densely packs intake air into the engine - compressed air up to 12 PSI that results in increased performance.

With its twin turbos, the EcoBoost V-6 swallows about 25 percent more air than its normally aspirated cousin, the 3.5-liter Duratec V-6.

"A turbo is basically a large air pump," explains Craig Stephens, EcoBoost powertrain control system manager. "Increasing the mass of air in the engine increases its power output, and that's why it's called ‘boost.' "

Two small is better than one large
The new EcoBoost engine strategically uses two small turbochargers rather than one larger one. This is to fight turbo lag, the tendency for previous generation turbocharged engines to have hesitation at low engine revs while the turbocharger spooled up to its operating speed.

The EcoBoost V-6 is the first application of twin turbos in a Ford.

EcoBoost's smaller turbines are quick to respond to throttle inputs, spooling up instantly. Mated with direct fuel injection, turbo lag in the EcoBoost V-6 is imperceptible and torque output is impressive, peaking earlier in the rev range than a comparable, normally aspirated V-8.

"EcoBoost gives the driver a very linear torque response," explained Corey Weaver, EcoBoost project leader.
"You get peak torque across a very wide engine speed range - usable performance that's available to you when you pull away from a stoplight or pass someone on a secondary road," he added. "You don't need to wind the engine out to get performance out of it. It's there all the time."

Yet, the EcoBoost engine has been engineered with such refinement that the driver never notices the turbocharger operation.

Sophisticated electronic controls, including active turbocharger wastegate control, work in conjunction with throttle control to balance boost and torque levels very precisely. The system controls wastegate pressure release and throttle position finely to give the driver the feeling of continuous torque delivery, without turbo "whines" and "whooshes" that characterized some previous-generation turbo engines.

The small size of the EcoBoost twin turbos allows them to be mated to compact, stainless steel exhaust manifolds, which reduce heat loss and facilitate close-coupled catalysts for emissions quality.

The turbo system runs at very high temperature, up to 950 degrees Celsius (1,740 degrees Fahrenheit). An air-to-air intercooler is used to cool the compressed intake air before it enters the combustion chamber. This allows it to be even more densely packed for optimal performance.

Engineered for reliable performance
The EcoBoost turbocharger system is engineered for long-term reliability, incorporating water cooling to protect the internal turbo bearings in the high-temperature operating environment. The water cooling system prevents the phenomenon known as oil coking, in which oil in previous-generation turbo bearings would bake and solidify, causing premature bearing failures.

The EcoBoost engine's turbo water cooling even works after the engine is switched off. The water cooling system is engineered to allow a process called reverse siphoning to take place. When the engine is switched off, the water pump ceases operation. The coolant in the extremely hot turbo boils and fresh coolant floods in behind it. This process continues until temperatures reduce, providing sustained, key-off protection for the turbo bearings.

Ford engineers have tested EcoBoost robustly in both engine dynamometer test labs and in real world environments ranging from high-temperature conditions to cold conditions down to minus 40 degrees Fahrenheit. Drivability, cold starts, high-altitude running and trailer towing were validated, and the Ford EcoBoost V-6 performed effortlessly in the place a V-8 engine would once have been.

"The EcoBoost engine has been designed and tested for use without any special operating precautions," said Michael Shelby, EcoBoost engine development leader. "You don't need to sit and idle before switching the engine off. You don't need to observe special oil-change intervals, and you don't need special oil."

The new 3.5-liter EcoBoost V-6 is offered initially as a premium engine for the 2010 Lincoln MKS and the 2010 Ford Flex, but the turbocharged Ford EcoBoost strategy is spooling up for more fuel-efficient, performance-rich engine products. By 2013, more than 90 percent of Ford's North American vehicle lineup will offer EcoBoost technology.