2011 FORD SUPER DUTY TURBOCHARGED DIESEL ENGINEERED, BUILT, AND TESTED IN-HOUSE
- An all-new 6.7-liter Power Stroke® V-8 turbocharged
diesel engine ““ debuting in the 2011 Ford F-Series Super Duty ““ will
deliver significantly improved torque and horsepower as well as
class-leading fuel economy, enhancing productivity and further
strengthening Super Duty’s position as the class leader for towing and
payload - Extensive durability testing put the new Power Stroke diesel engine through the equivalent of 250,000 miles
- Turbocharger
with industry-first dual-sided compressor wheel delivers fast throttle
response along with the volume of air boost needed for maximum power;
new engine also is biodiesel compatible up to B20
DALLAS, Sept. 24, 2009 ““ A new era in Ford diesel technology arrives
with the Ford-engineered, Ford-tested and Ford-manufactured 6.7-liter
Power Stroke® V-8 turbocharged diesel engine.
Debuting in the next-generation Ford F-Series Super Duty truck, the
new diesel engine will deliver significant improvements in torque and
horsepower as well as class-leading fuel economy while adding more
fueling flexibility and easily meeting stringent new emissions
requirements.
The new diesel 6.7-liter engine also shares the Super Duty’s
legendary reliability and durability while delivering best-in-class
towing and payload.
“This all-new diesel engine has been so extensively tested both in
the lab and in the real world that we’re confident we’re giving our
customers the most reliable and productive powertrain available today,”
said Derrick Kuzak, group vice president of Global Product Development.
“Our Super Duty customers demand reliability and durability in their
trucks so they can deliver the best results for their business and
their customers. That’s exactly what this engine delivers.”
The diesel engine team made improvements and changes throughout the
engine architecture to deliver on aggressive horsepower, torque,
emissions and fuel economy targets. The 6.7-liter Power Stroke uses an
“inboard exhaust” architecture, an automotive-industry first for a
modern production diesel engine. It combines the best of proven
technology with new, patented approaches backed by an extensive
laboratory and real-world testing regimen to assure customer
satisfaction.
Benefits of the new 6.7-liter Power Stroke V-8 turbocharged diesel engine include:
- First use of a compacted graphite iron (CGI) engine block
in a Super Duty-class vehicle in North America; stronger than cast
iron, Ford has successfully used CGI in engine blocks in products
around the world. The block structure was optimized for reduced weight
and maximum strength to meet the demands of higher torque and
horsepower.
- Unique inboard exhaust and outboard intake architecture,
an automotive-industry first for a modern production diesel engine,
reduces overall exhaust system volume, which leads to better throttle
response for the customer; additionally, reduced exhaust system surface
area minimizes heat transfer to the engine compartment and improves NVH
(noise, vibration, harshness) performance.
- The new engine architecture enables easier service work
for all major engine components, potentially reducing down time. On
turbocharger service, for example, the body/cab no longer has to be
removed from the frame to access the turbo; also, the high-pressure
fuel pump, EGR (exhaust gas recirculation) components and thermostats
are directly accessible from the front of the vehicle.
- Honeywell’s VNTâ„¢ (variable nozzle turbine) DualBoost
turbocharger features an industry-first dual-sided compressor wheel
that works in a single housing. The unit is uniquely center-mounted on
a pedestal low in the back of the valley for improved NVH. This
turbocharger design allows the single unit to deliver the benefits of a
twin-turbocharger system in a smaller, more efficient package,
combining the benefits of a small turbocharger (faster response) and a
large turbocharger (ability to compress and force more air into the
engine for more power) in one unit.
- The high-pressure Bosch fuel system injects fuel at more
than 29,000 psi. The system delivers up to five injection events per
cylinder per cycle using eight-hole piezo injectors to spray fuel into
the piston bowl. The direct-injection system is calibrated and phased
for optimum power, fuel efficiency and NVH performance.
- Aluminum cylinder heads for reduced weight; the mid-deck
construction with dual water jackets provides increased strength and
optimal cooling; also, six-head bolts, instead of four as found on
other engines, help improve sealing and maintain cylinder integrity
even with the higher firing pressures; overall the engine is about 160
pounds lighter.
- Compatible up to B20 fuel, allowing greener fueling options of up to 20 percent biodiesel and 80 percent petroleum diesel.
“Our Super Duty customers are no-nonsense, no-compromise
individuals,” said Barb Samardzich, Ford vice president, Global
Powertrain Engineering. “Those are the attributes our team took to
heart when engineering this all-new diesel engine so we can deliver
Built Ford Tough capability, reliability and enhanced productivity.”
Rugged block and proven components
The capability and reliability found in the new 6.7-liter diesel engine
starts with the engine block. The new Power Stroke’s block is made from
compacted graphite iron (CGI), which is about twice as strong as cast
iron. While this is the first use of a CGI block in North America in
this class of vehicle, Ford has successfully used the material in
engine blocks in other products around the world.
“Using a CGI block is the perfect solution for the new 6.7-liter
Power Stroke,” said Adam Gryglak, lead 6.7-liter diesel engineering
manager. “It provides the strength necessary for the increased torque
and horsepower produced by our new engine, and it also offers
significant weight savings.”
The diesel engine’s deep-skirted block and main bearing caps are
cross-bolted for additional stiffness and to aid NVH. The cylinder
heads mirror the engine’s attributes as a whole, with lighter weight
combined with increased robustness: The cylinder heads are made of
aluminum to save weight and, for improved sealing, feature six-head
bolts per cylinder instead of the four-head bolts found on other
engines.
The cylinder heads, which feature dual water jackets, are capable of
firing pressures approaching 2,600 psi. The tall water jacket works as
a manifold, flowing high-velocity water for cooling and adding to the
structural robustness in the head to handle the higher firing
pressures. Crankshaft durability is improved through Ford’s unique
undercut and fillet roll treatment to relieve stress.
The valvetrain features patented dual hydraulic lash adjustors,
which improves the performance and reliability of the valvetrain by
using two pushrods per cylinder instead of the conventional single
pushrod, with individual rocker arms. Other proven components round out
the engine hardware, including fractured-split connecting rods and a
fuel system capable of generating 29,000 psi to feed the common-rail
direct-injection fuel system.
The oil pan, which bolts to the transmission, also acts as a
structural member for improved powertrain stiffness and adds to Ford’s
legacy of virtually bulletproof lower-engine architecture.
Built Ford Tough testing protocol to ensure durability
The testing protocol developed for the 6.7-liter Power Stroke V-8
turbocharged diesel incorporates the most rigorous engine tests found
in Ford globally to ensure 250,000-mile durability. Extensive CAD
(computer-aided design) and CAE (computer-aided engineering) work was
completed to identify any potential challenges before hardware was
created, which not only is time efficient but also helps ensure quality
at the outset. Further, a comprehensive examination of warranty data
and quality tools was used to determine the expected failure modes for
every component and system.
Customer data, including driving styles, road types and vehicle
usage (towing and payload), also played a key role in developing the
testing program that best replicated Super Duty use.
Components were torture-tested in the laboratory with a regimen
designed to exceed what even the most extreme-use customer might dish
out. Engines literally ran continuously for hundreds of hours. Finally,
a battery of in-vehicle, real-world tests validated the work done in
the laboratories.
The strict testing work also ensured the new engine is B20
compatible, which allows customers a fueling option of using blends up
to 20 percent biodiesel and 80 percent petroleum diesel. Durability
cycles were run on multiple blends of diesel fuel to ensure the
robustness of the system.
“These cross-functional tests give us the full spectrum of Super
Duty customers ““ from those who run their trucks at maximum power with
a maximum load for long periods to those who use them more in a
start-stop mode,” said Ed Waszczenko, lead engine durability engineer.
All-new design for all-new engine
One of the obvious visual differences in the new 6.7-liter Power Stroke
V-8 turbocharged diesel engine is the layout of the pipes. The exhaust
manifolds, for example, reside in the valley of the engine instead of
outboard, while the intake is outboard of the engine. The cylinder
heads are essentially flipped around in comparison with previous V-8
engine architectures.
This unique layout ““ an automotive-industry first for a modern
production diesel engine ““ has several advantages. First, the overall
exhaust system volume is reduced, meaning air can be fed to the single
turbocharger quicker for faster spool up and reduced lag, resulting in
improved throttle response for the customer. The improved packaging
also places components that need to be in cooler air away from hot
exhaust pipes, resulting in better thermal management and, by
extension, better fuel economy.
“The physical size of the system is smaller, but more importantly,
the air-handling part of the system is considerably smaller and that
translates directly into the responsiveness of the engine,” said
Gryglak, noting that the volume of the exhaust system feeding the
turbocharger is smaller by about 50 percent because of the inboard
architecture.
Combining two turbochargers in one package
The single-sequential turbocharger ““ an industry first ““ is key to the
new diesel engine’s performance. The unit has two compressor wheels
driven off one turbine impeller. This approach combines the benefits of
a single inertia wheel ““ faster response without lag ““ with the thrust
of a larger turbocharger, with the ability to force more compressed air
into the engine for more power.
The engine’s smaller exhaust volume combined with a corresponding
smaller intake volume and smaller turbocharger creates a system that is
quicker to boost, more responsive and better able to deliver horsepower
and torque, especially at the low end, when the customer demands it.
The turbocharger includes an advanced variable nozzle turbine, which
enables variable vane pitch angles, driving optimal turbine power to
achieve optimal boosting levels for all operating conditions. The
single shaft ensures the transition is seamless. The unit ““ compact in
dimensions ““ is uniquely center-mounted on a patented pedestal low in
the back of the valley instead of hung off the block, which helps
balance the system and aids NVH performance.
Combustion system clean and powerful
The combustion system is the heart of the new 6.7-liter Power Stroke
V-8 turbocharged diesel engine and in many ways encapsulates the
careful balancing act the Ford team achieved in terms of power, fuel
economy and reduced emissions. The key factor in the next round of
federal emissions standards, which begin in 2010, is the reduction of
oxides of nitrogen (NOx). To help reduce NOx, the new Power Stroke
burns cleaner, thanks to an innovative way Ford developed to cool the
exhaust gas recirculation (EGR) to efficiently recycle the combustion
gases in the system.
Ford’s system runs the engine with the least amount of oxygen
possible in order to reduce NOx without degrading performance and fuel
economy. Ford’s solution runs the EGR through a two-step process
utilizing separate cooling sources, something not typically seen. The
end result is the EGR is brought into the intake at a lower
temperature, which means more of it can be utilized, creating greater
efficiency throughout the system.
A unique piston bowl design and the high-pressure fuel-injection
equipment are huge enablers in achieving the balance of power and lower
emissions. The system can deliver up to five injection events per
cylinder per cycle, while eight holes in the injector spray fuel into
the bowl.
The compressed-air ignition unique to diesels is aided by pilot fuel
injections before the piston reaches the top, allowing the charge to
heat up even hotter than what you get under normal compression.
“Then when the main injection occurs, we can mitigate NVH because we
have a slower ignition process,” said Gryglak. “When the fuel burns, it
doesn’t burn with a traditional pop or bang. The direct-injection
system is calibrated and phased for optimum power, fuel efficiency and
NVH.”
The new diesel engine features instant-start glow plugs, allowing quick start even in extremely cold temperatures.
How the new Power Stroke meets new emissions standards
The new 6.7-liter Power Stroke V-8 turbocharged diesel will employ an
aftertreatment system to help comply with 2010 federal regulations to
reduce nitrogen oxide levels in diesel emissions by more than 80
percent compared with the previous standard. The Ford aftertreatment
system is a three-stage process; a key component is the use of Diesel
Exhaust Fluid (DEF).
Injection of DEF to reduce NOx is a proven technology that’s been
used throughout the automotive industry. Unlike other solutions used to
control NOx, the DEF system allows the diesel engine to run at its
optimum range in terms of fuel mixture. Some systems require the engine
to run richer ““ which can be harmful to diesel engines ““ in order to
control the NOx.
Step One: Cleaning and Heating ““ The first step in
cleaning the diesel exhaust occurs when the exhaust stream enters the
Diesel Oxidation Catalyst (DOC). The role of the DOC is twofold. First,
it converts and oxidizes hydrocarbons into water and carbon dioxide.
This conversion happens at about 250 degrees Celsius.
Second, the DOC is used to provide and promote heat, using specific
engine management strategies, into the exhaust system. Through
appropriate thermal management, this heat increases the conversion
efficiency of the downstream subsystem(s) in reducing emissions.
Step Two: Knocking Out the NOx ““ The next step in
the process is what’s known as Selective Catalytic Reduction (SCR). In
this process, the NOx in the exhaust stream is converted into water and
inert nitrogen, which is present in the atmosphere and harmless. Before
the exhaust gas enters the SCR chamber, it is dosed with DEF, an
aqueous solution that is approximately 67.5 percent water and 32.5
percent pure urea.
When heated, the DEF splits into ammonia and carbon dioxide. These
molecules are atomized and vaporized, then enter a mixer that resembles
a corkscrew. This twist mixer evenly distributes the ammonia within the
exhaust flow. The ammonia enters the SCR module, which contains a
catalyzed substrate, and through chemical reactions combines and
converts the NOx and ammonia into the harmless inert nitrogen and
water. Dosing occurs between 200 and 500 degrees Celsius.
Step Three: Scrubbing Away the Soot ““ The final
part of the cleansing system for the diesel exhaust gas involves the
Diesel Particulate Filter (DPF). The DPF traps any remaining soot,
which is then periodically burned away, known as regenerating, when
sensors detect the trap is full. The regeneration process sees
temperatures in excess of 600 degrees Celsius to burn away soot.
Quieter, more refined diesel sound for improved NVH performance
Customers of the 6.7-liter Power Stroke turbocharged diesel engine will
notice a quieter, more refined sound. Improvements to the combustion
system, structural integrity of the compacted graphite iron block and
the single turbocharger mounted to the engine block account for many of
the NVH improvements.
Specific design upgrades were made to both the piston and the piston
bowl to optimize the combustion process, which features a two-stage
combustion event instead of a single-injection event, causing harsh,
sudden and loud combustion. Instead, a starter or pilot injection of
fuel begins the combustion process before the main injection.
The result is smoother combustion and a more refined sound for the
customer. When at idle, two pilot injection events are used to make the
firing process even smoother and aid in quietness. The “ticking” of the
high-speed injectors also is quieted by specially designed covers on
the engine.
Mounting the turbocharger from the center housing directly to the block provided several advantages as well in terms of NVH.
“When turbochargers vibrate, it can lead to other parts of the
vehicle vibrating,” said Scott DeRaad, engine NVH engineer. “The
exhaust system, for example, is directly attached to the turbocharger.
So when the turbocharger vibrates a lot, the exhaust system vibrates
too and that’s disturbing to the customer. Bolting the turbocharger
directly to the block eliminates that concern.”
Using one turbocharger, instead of two operating in series or sequentially, helped solve some NVH challenges as well.
“Having one turbocharger eliminates the air-handling noises ““ the
whooshes ““ as the engine switches from one turbo to the next turbo,”
DeRaad said. “Our turbocharger also has ball bearings that pilot the
shaft in the turbo, which helps eliminate the potential for the shaft
of the turbocharger to gyrate in its housing, which can create noise.”
Other improvements include the addition of two resonators in the
intake system as well as a third resonator near the air cleaner.
“We’ve been able to tune the diesel intake system to give us the
sound we wanted,” DeRaad said. “It’s now a nice complement to the
engine.”
The new diesel engine, which will be built at Chihuahua Engine
Plant, is the perfect complement to the 2011 Ford Super Duty,
delivering both capability and reliability.
“Developing the new 6.7-liter Power Stroke V-8 turbocharged diesel
engine was an awesome endeavor,” Gryglak said. “After all the
engineering and testing, we’re confident this engine will ensure the
new Super Duty continues its leadership in capability, reliability and
productivity.”
Come check out the discussion on the new Super Duty!
