Press Release
ACHIEVING V-8 POWER WITH V-6 FUEL EFFICIENCY MEANS MORE PRESSURE UNDER AN ECOBOOST VEHICLE'S HOOD
* There's more pressure under the hood of an EcoBoostTM engine-equipped vehicle, thanks to its unique technology that combines turbocharging and direct fuel injection. Compared with a typical engine system, the operating pressures of EcoBoost's fuel and air induction systems are significantly higher
* The new 3.5-liter EcoBoost V-6 operates at fuel pressures about 35 times higher than the typical port-fuel injected (PFI) gasoline engine. Precisely controlled, EcoBoost fuel pressure ranges from 200 to 2,150 pounds per square inch (PSI), compared with about 60 for the typical PFI engine
* Turbocharging boosts the pressure of intake air feeding the EcoBoost engine to deliver V-8 style performance from a V-6. EcoBoost operates with a boost level of 8-12 PSI
It's a high-pressure role to achieve the power of a V-8 with the fuel economy of a V-6, but the new Ford EcoBoost engine debuting in the Lincoln MKS, MKT and Ford Flex knows how to handle pressure.
That's because there's more fuel and air pressure under the hood of an EcoBoost engine-equipped vehicle. Different technology is the reason.
Turbocharging and direct fuel injection - the dynamic duo in Ford's strategy to deliver affordable fuel efficiency improvements for millions - put different demands on the underhood environment than the typical car. Operating pressures of EcoBoost's fuel and air induction systems are significantly higher.
The new EcoBoost engine has been engineered to harness those pressures. The benefits in terms of performance and fuel efficiency are considerable.
"Combining direct injection and turbocharging to create EcoBoost brings specific advantages," said Michael Shelby, EcoBoost engine development leader. "With EcoBoost, we use smaller-displacement engines in place of larger engines. Turbocharging delivers the performance and direct injection enables fuel efficiency while mitigating turbo lag and minimizing emissions."
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).
What's so different about an EcoBoost engine?
Fuel Pressure - A typical PFI gasoline engine delivers fuel into the intake manifold - and indirectly into each cylinder - at a pressure of about 60 PSI. EcoBoost delivers fuel directly into each cylinder at a much higher pressure, up to 2,150 PSI - that's 35 times the pressure.
Fuel to an EcoBoost engine starts its journey from the fuel tank at a similar pressure to that of a typical PFI engine. But that's where the similarity ends.
A high-pressure, cam-driven pump on the engine is used to pressurize the fuel in a rail structure on each side of the EcoBoost V-6. The pressurized fuel in each rail supplies fuel to the injectors themselves.
The solenoid-controlled injectors create a fine, high-pressure spray pattern through six holes directly into the cylinder. The pressure and duration of each injection is precisely controlled by the vehicle's powertrain control module.
This fine, high-pressure mist is designed for optimal combustion efficiency, especially in the dense, turbocharged air.
Even at idle, the fuel pressure at the injectors is more than three times that of a PFI engine. The operating pressure range is between 200 and 2,175 PSI.
"The EcoBoost engine is constantly controlling the rail pressure to a target level based on what the customer is demanding from the engine," explained Todd Rumpsa, EcoBoost calibration supervisor. "As the driver increases demands on the engine, higher rail pressures maintain optimized combustion performance by delivering the best atomization of fuel and the precise injection duration."
Air Pressure - A typical, normally aspirated PFI engine draws unpressurized air into the intake manifold. The EcoBoost V-6 uses twin turbochargers to boost the pressure of the intake air and the increased mass of air entering the engine increases power output. EcoBoost pressurizes the intake air 8-12 PSI.
The turbocharger uses exhaust gas to spin compressor blades at high speed - approximately 170,000 rpm. An intercooler helps to cool the intake air, making the charge air more dense and increasing the performance potential.
"Turbocharging is very efficient because it uses the energy of the engine's exhaust gas, which would otherwise be wasted, to boost the pressure of the intake air," explained Shelby.
Oil Pressure - Although the EcoBoost engine does not differ significantly from a PFI engine in terms of engine oil pressure, the Ford EcoBoost V-6 still makes clever use of its oil pressure to deliver its enhanced performance and fuel efficiency.
That's because the EcoBoost engine delivers a short spray of oil to the underside of each piston on each stroke. "Squirt jets" deliver a 25-PSI dose of oil to the piston. This achieves a cooling effect that aids combustion efficiency.
The squirts have an important side benefit, too. On cold startup, the squirts help to warm the oil to optimal operating temperature more quickly, which improves the fuel economy.
"EcoBoost engine technology is about managing the pressures to extract the maximum in terms of performance and fuel economy," Rumpsa says. "We know we've done our job when customers don't even notice what's happening in the engine compartment. They just need to concentrate on enjoying the responsive V-8 power and torque and the excellent V-6 fuel economy."
