When Americans think of improving fuel economy, they most often think of hybrids. The Toyota Prius has become not just a car but an icon for the environmental set. Engineering types who look at hybrids, though, see a bevy of complicated systems that mean added expense for their companies -- and for the consumer. Because of this, a number of auto manufacturers, Ford Motor Co. prominent among them, are revisiting a technology that had its heyday in the ’70s and early ’80s: turbocharging. But this time there is a twist. With its EcoBoost system, a technology we should see in showrooms in 2009, Ford has added direct injection to the equation. This means that fuel is precisely metered directly into the combustion chamber of the engine, making for better fuel economy and emissions performance.
Turbocharging was typically used in the past to promote performance by boosting horsepower, but durability problems gave turbos a bad rap back in the ’80s. These days, though, the EcoBoost is aimed at enhancing economy, and the technical issues that used to plague turbochargers -- throttle lag and bearing failure -- have been conquered. And just to make certain we don’t see a repeat of the failures of past decades, Ford is putting its new 3.5-liter EcoBoost V6 engines through a grueling series of tests.
“EcoBoost was engineered with a relentless, disciplined focus on quality that required a zero-defect mindset from engineers as well as our supplier partners,” said Derrick Kuzak, Ford’s group vice president, global product development. “The finished product will represent the best combination of production-ready engine technologies of today, poised and ready to deliver the performance, fuel economy, emission levels and value that customers expect.”
As this is being written, a fleet of direct-injection twin-turbocharged 3.5-liter EcoBoost V6 engines have endured more than 12,000 hours of durability operation in Ford’s Dynamometer Laboratory in Dearborn, Mich., which is equivalent to more than 500,000 miles of customer driving. The Ford testing includes 20 individual dynamometer-level tests designed to push the engine to its limits. The testing protocol is designed to verify the reliability of the complete engine system under maximum engine speeds and loads, coolant and oil temperatures and customer driving patterns.
The Road Cycle Durability test, for example, was created to replicate real-world customer driving and vehicle-maintenance patterns. For this test, engines with EcoBoost technology were subjected to 1,000 cold starts, followed by sustained operation at peak torque of 340 pound-feet and peak power of 340 horsepower -- the kind of punishment an engine will never receive in customer hands. In total, this single test required 1,000 hours of extreme engine operation, representing more than 60,000 miles of customer driving.
The Ford engineering team took extra measures to test the EcoBoost’s durability, creating a subset of checks on the reliability of critical components. As you might expect, at the top of this checklist were the high-pressure direct-injection fuel system and parallel-operating twin turbocharger boost system. It is the pairing of these two technologies that give an EcoBoost engine the ability to perform like a V8 engine while offering the fuel economy associated with a smaller displacement engine like a V6 or even a four cylinder.
“Because the 3.5-liter EcoBoost employs the latest in injection and turbocharger thermal management technologies, our tests have shown that we have effectively eliminated the legacy concerns sometimes associated with these systems, including high-mileage combustion deposits on the injectors and turbo bearing coking,” said Brett Hinds, Ford’s advanced engine design and development manager.
Beyond the dynamometer tests in the laboratory, Ford engineers are completing durability testing with installed EcoBoost engine systems on a mix of products, including the Lincoln MKS and Ford Flex at Ford’s Michigan Proving Ground. There the EcoBoost fleet is being subjected to multiple on-track tests to measure its performance at, for example, high speeds and while towing a trailer. In total, these on-track exercises will rack up the equivalent of another 500,000 miles of customer driving, bringing total durability test miles for the 3.5-liter EcoBoost V6 fleet to more than one million.