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™ 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
Detroit, Jan. 11, 2009 – 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.
exhaust gas to
pump more power
out of a
engine. The new
engine uses twin
with direct fuel
injection – to
punch above its
size in terms of
It produces the
torque of a
efficiency of a
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.’ ”
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.
the driver a
“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.
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.
RED-HOT TORTURE: NEW ECOBOOST ENGINE’S TURBOCHARGERS GLOW IN DURABILITY TESTING
Ford’s new EcoBoost Engine
- The reliability of the new Ford EcoBoost™ V-6 engine is a hot topic at Ford. That’s because EcoBoost’s twin turbos glowed orange-hot while enduring – and passing – extremely rigorous durability testing in Ford engine dynamometer lab. Ford engineers ran EcoBoost at maximum boost continuously for hundreds of hours under far more severe conditions than customers are expected to dish out
- Designed for long-life reliability, EcoBoost’s turbochargers feature water-cooled bearing jackets. This architecture is designed to prevent oil “coking” that could occur in previous-generation turbochargers. The new design means that EcoBoost drivers don’t need to observe special operating precautions, such as idling the engine before switching it off
- The new 3.5-liter EcoBoost engine features normal gasoline engine service intervals of 7,500 miles and uses the same 5W20 engine lubricating oil as Ford specifies for other gasoline engines
Working to ensure the long-life reliability of the dual-turbo, direct-injected engine, Ford put the new engine through a barrage of torture testing.
One of the key areas of testing focused on the two turbos – key weapons in the EcoBoost strategy to deliver the performance of a V-8 with the fuel economy of a V-6. Would their reliability match the rest of the robust engine architecture, based on Ford’s proven 3.5-liter V-6 engine?
“The answer is yes,” says Michael Shelby, EcoBoost engine development leader. “We put the EcoBoost V-6 through the same extensive durability signoff testing as any Ford gasoline engines, and we went beyond it to validate the EcoBoost water-cooled turbocharger design and air-to-air intercooling strategy.”
The EcoBoost system is part of Ford Motor Company’s commitment to deliver the best fuel economy in each new vehicle, with at least three more additions for the 2010 model year. The 2010 EcoBoost Flex, for example, boasts segment-leading fuel economy among full-size performance crossover vehicles, with 22 mpg highway and 18 mpg combined. The 2010 EcoBoost MKT also leads its segment in fuel economy, exceeding the V-8-powered Audi Q7 by 4 mpg highway. With its premium EcoBoost engine, the new Lincoln MKS will deliver more power and better highway efficiency (25 mpg) than the 2009 Lexus GS460 (24 mpg) or 2009 Infiniti M45 (21 mpg).
Engine Dynamometer ‘Torture Chamber’
Going beyond the normal test protocol meant ramping up the boost to the maximum in special Ford engine dynamometers. These dedicated test cells allow engineers to operate the engine exactly as it would operate in a vehicle.
“The idea is to run the engine through a very difficult testing regimen at its maximum-rated operating performance,” Shelby explained. “That’s when things get hot.”
Once the EcoBoost engine was installed in the dynamometer, operators increased rpm to full boost operation.
This meant the turbos were running flat out at incredibly high temperatures. “That’s beyond red hot,” Shelby says. “They’re orange hot.”
Reliable to the Extreme
Turbochargers operate at high speed – up to 170,000 rpm – and under intense temperatures of up to 950 degrees Celsius (1,740 degrees Fahrenheit). Some previous-generation turbos were reputed to suffer from oil coking, in which they would bake their lubricating oil. Because oil coking can lead to premature turbocharger bearing failures, Ford’s advanced engine engineers specified the use of new, water-cooled turbochargers to combat this problem.
“During normal turbo operation, the turbo receives most of its bearing cooling through oil,” said Keith Plagens, turbo system engineer. “After shut down, the problems with turbos in the past were you would get coking in the center bearing. Oil would collect in the bearings, the heat soaks in and the oil would start to coke on the side and foul the bearing. Water cooling – used in the EcoBoost engine – eliminates that worry.”
The new EcoBoost V-6 uses two Honeywell GT15 water-cooled turbos.
“The EcoBoost engine uses passive thermal siphoning for water cooling,” Plagens explains. “During normal engine operation, the engine’s water pump cycles coolant through the center bearing. After engine shutdown renders the water pump inactive, the coolant flow reverses. Coolant heats up and flows away from the turbocharger water jacket, pulling fresh, cool coolant in behind. This highly effective coolant process is completely silent to the driver, continuing to protect the turbocharger.”
for a Spin - Flat Out
To validate their water-cooled turbo design choice, Ford engineers put EcoBoost through a special turbocharger test.
The test ran EcoBoost at maximum boost flat out for a 10-minute period. Then the engine and all cooling were abruptly shut down and the turbo was left to “bake” after this high-speed operation. If that sounds severe, imagine repeating this cycle 1,500 times without an oil change. That’s what EcoBoost’s turbos endured.
After 1,500 cycles, the turbos were cut open for detailed technical examination. The turbos passed the severe test with flying colors.
“We’ve attained things here the customer would never be able to do in their vehicle,” Plagens said. “Ten minutes of peak power (355 hp, 350 foot-pounds of torque) is something that’s probably only achievable in a vehicle for fractions of a minute, 10 seconds maybe in the extreme. We run it for 10 minutes many, many times over, and that’s far, far more harsh and severe than a vehicle test would be.”
EcoBoost also endured Ford’s standard engine durability test signoff. Back in the dynamometer lab, the 3.5-liter EcoBoost V-6 went back up to full revs – and maximum turbo boost – for a real endurance test. This time the duration was a bit longer – 362 hours at full throttle. That’s like running the 24 Hours of Daytona for more than 15 days straight.
Other tests subjected EcoBoost to a grueling range of operating temperatures.
“We run all of our durability testing at the maximum temperature,” Plagens said. “For the turbos, the test is 150 hours long. Every 10 minutes the test alternates between peak power at max exhaust temperature and completely cold motoring. The goal is to verify that the turbochargers can withstand extreme thermal cycling without affecting their performance. It’s pretty brutal and extreme but it’s important to prove out durability.”
Making the Grade
As the first Ford EcoBoost engine makes its production debut, it has earned its stripes in Ford’s engine boot camp. It uses that same grade of 5W20 engine oil specified by Ford for gasoline engines, and oil changes are scheduled at the same 7,500-mile intervals, too.
“Ford customers can be sure that their new EcoBoost engine requires no special treatment for its reliable operation,” Shelby said. “EcoBoost owners can pull in their driveways and switch off just like any other engine, and there’s no special oil or shorter oil-change intervals. That means the owner can concentrate on enjoying the great performance and fuel economy.”