The Five Percent Solution
Christopher A. Sawyer
“Many of the team members that delivered the 6.7-liter Power Stroke are responsible for delivering the 3.0-liter Power Stroke as well,” says Ford Diesel Technical Leader David Ives.
And he is among them. Ives adds, “Though the original V6 diesel was done in partnership with Peugeot many years ago, this has always been a Ford-engineered engine.” It’s also been one with wide and varied uses, powering everything from Citroën and Peugeot sedans to Land Rovers, Range Rovers and Jaguars. And its Europe-centric usage meant production was located at Ford’s facility in Dagenham, England.
The Gen 3 version of the V6 increased the bore and stroke of the original 2.7-liter motor from 81 x 88 mm to a still undersquare 84 x 90 mm, the exact dimensions used in the F-150 diesel.
Further similarities include the continued use of a compacted graphite iron engine block, high-strength aluminum cylinder heads with belt-driven dual overhead cams and four valves per cylinder, cross-bolted main bearing caps, and a 2,000-bar (29,000-psi) common rail direct injection fuel system with piezo-electric injectors. Even the power output is the same at 250 hp and 440 lb.-ft. But, Ives cautions, it’s not the same engine.
Ives says the Gen 3 “was a good foundation from which to start, but we made a lot of changes to make it fit the F-150 user profile.” Though the fuel injection pressure was increased from 1,650 bar to 2,000 when the V6 was enlarged, Ives and his team specified a more precise injector design to improve fuel economy and emission performance. Also, the twin variable-geometry turbochargers were replaced by a single Honeywell unit mounted near the right-hand exhaust manifold, and it draws from the left-hand bank via a flow-optimized tube at the back of the block. In addition, extensive changes were made to the cooled EGR system, which required changes to the cooler, valve geometry and associated plumbing.
Mounted on the left side of the engine, the EGR cooler supplies the back of the throttle body via a steel flex tube. The result is an engine tuned for a broad torque band and part-throttle fuel economy while under load. (Full torque is available from 1,750-2,250 rpm and doesn’t drop below 300 lb.-ft. until approximately 3,750 rpm.)
Not surprisingly, the 3.0-liter Power Stroke packages in the same area as the naturally aspirated 3.3-liter V6, and twin-turbo 2.7- and 3.5-liter EcoBoost V6 gas engines. However, it wasn’t a simple drop-in operation. “We had to design a new oil pan that fit around the F-150’s frame rails,” says Ives, “and it is unique to this application.” The die-cast pan adds structure to the bottom end, and—in conjunction with the tuned elastomeric damper on the crank pulley—helps dampen NVH levels.
Unlike its gasoline-fueled brothers, however, the 3.0-liter diesel features a mechanical fan with an electronically controlled viscous clutch to go with dual radiator shutters. According to Ives: “This improves cooling when towing heavy loads in hot weather and gives us the capacity to move much more air across the radiator and intercooler.
Unlike our competitors who use electric fans, we don’t have to dial back on power when the boundary condition presents itself.” In addition, the combination of the electronically controlled radiator shutters and mechanical fan lets the cooling system balance both fan load and aerodynamic efficiency as needed.
The 3.0-liter Power Stroke is not as light as its EcoBoost counterparts, but—at 487 lb. (221 kg.)—its weight is comparable to a gasoline V8, and well below the 1,000 lb. (454 kg.) of its 6.7-liter big brother. Start-stop is standard, as is a 10-speed automatic transmission, and Ford expects the engine to get a 30 mpg highway mileage rating from the EPA. That’s four mpg better than the F-150’s next most economical engine, the 2.7-liter EcoBoost V6. However, the real-world fuel economy difference should be even greater. “Launching with a heavy trailer is a distinct advantage with the diesel,” says Ives, “but once that load is rolling, the fuel efficiency advantage with a diesel is significant.” Ford claims the 3.0-liter Power Stroke-equipped F-150 has a best-in-class towing capacity of 11,400 lb. and a payload capacity of 2,020 lb.
After-treatment is a three-stage process that includes an oxidation catalyst, selective catalyst reduction and a diesel particulate filter. “The system,” says Ives, “is specific to the 3.0-liter, but is very similar to what is used on the 6.7-liter Power Stroke. Much of what we learned there has been put into use on the new engine.”
Question how VW’s travails affected the decision to add a diesel to the F-150, however, and you are met with a steely, “Our products comply with all emission standards, and have not—and do not—use any form of defeat device.” You can understand the consternation, especially with trial lawyers the world over accusing any and every automaker of wrongdoing. However, F-150 Marketing Manager Brian Bell foregoes the legalese for a direct answer as to why Ford put in this level of effort for an engine that will be just five percent of the mix: “There’s stuff that happens in the industry, and you can’t let that impact what you do.
Truck customers understand diesels, and real-world fuel economy when towing or hauling, something they do frequently, is very important to them. Desire for a diesel in the F-150 has been growing, but it wasn’t until we had the 2015 truck in place that it really made sense to pursue it, and to do so with an architecture we had in our portfolio that we knew could meet the customer’s needs as well as current and future emission standards.”
While the whole notion of minivans might provoke an involuntary eye roll among some people, here’s an interesting fact: so far this year, through the end of March, Chrysler delivered 31,616 Town & Country minivans, which makes it, by far, the biggest selling vehicle in the brand’s showroom.
Mercedes has been putting diesels in vehicles since 1926. It has been offering them in the U.S. since 1949. And 2013 is seeing a range of offerings, including in its popular GLK SUV.
There are two things that are true of automotive journalists: they like station wagons.