Anyone seen, or herd of any indipendent reveiws of the new diesel? This is coming out soon and the urea injection system for the exhaust sure looks like a California idea, any word if it works in a Canadian winter? This info looks scripted by FoMoCo PR
staff, but sure sounds like some cool tech is coming soon! I hope it's better than the last gen navistar diesel.
clik the link to see entire artical
Ford is rewriting the rules of the company and industry with the introduction of its all-new advanced 6.7-liter Power Stroke V-8 diesel engine for the 2011 F-Series Super Duty pickups.
“The 6.7-liter diesel puts the motor back in Ford Motor Company,” said Adam Gryglak, the engine’s lead engineer. “This is the most advanced Power Stroke yet with the cleanest emissions,” lower noise, vibration and harshness “and substantially improved power and fuel economy.”
Codenamed “Scorpion,” the 6.7-liter PSD is Ford’s first-ever designed-in-house pickup truck diesel engine since the first oil burner (International’s 6.9-liter V-8) was offered under the hood of a Ford pickup in 1982.
“This was a global effort within Ford to create this engine,” Gryglak said. “We applied many of the lessons learned from Ford’s European operations.”
Ford’s road to the Scorpion has been long and winding. The 6.7-liter PSD is the third all-new heavy duty diesel engine in 7 years and the fourth since production of the 7.3-liter Power Stroke ended in 2002.
Its creation can be traced back to the 6.0-liter Power Stroke that Ford introduced for its 2003 Super Duty pickups. Ford and Navistar (International’s parent company) went to battle in court over warranty problems and cost issues related to that engine, which ultimately led to both companies ending their 30-year diesel manufacturing relationship in January. Ford kept the rights to the well-known Power Stroke name that has been associated with Ford diesels since 1994.
No more Navistar. The 6.7-liter Power Stroke V-8 is Ford's first diesel motor for its F-Series pickups to be developed entirely in-house after three decades partnering with the contract engine manufacturer. It will be built at Ford's plant in Mexico.
Ford introduced the 6.4-liter Power Stroke for its 2008 Super Duty pickups in order to meet tough emissions laws that required an immediate 90-percent reduction in soot, a natural byproduct of diesel combustion; General Motors and Chrysler did the same.
Clean-air regulations will be ratcheted up again on January 1, 2010. Diesel-powered pickups built after that date will have to have engines that reduce nitrogen oxide emissions by 90 percent from today’s standards and by 96 percent from 1994 standards.
NOx is a major air pollutant that contributes to smog, asthma, and respiratory and heart diseases. It's caused by diesel’s high combustion temperatures, which results from the high frictional heat created by compressing air in the cylinders to the point where it can ignite diesel fuel without using a spark.
But where GM and its engine development partner Isuzu have been able to reuse the basic architecture of the 6.6-liter LML Duramax V-8 diesel engine introduced in 2001, and Dodge is carrying over the 6.7-liter Cummins I6 that’s been in service since 2007, the Ford 6.7-liter V-8 is an almost total clean sheet redesign that uses many unconventional solutions to meet the needs of its drivers and the EPA.
Reverse Flow Design
The Scorpion’s architecture shares several key traits with GM's indefinitely postponed 4.5-liter Duramax V-8 diesel engine. Most notably, the intake and exhaust flow through the cylinder heads is reversed when compared to a conventional diesel engine, with the exhaust exiting directly into the engine’s turbo that sits in the engine's valley, mounted between V-style cylinder banks.
“When we looked at the at the design imperatives of the program we were looking to ensure that we delivered improved performance, fuel economy, NVH and heat management with the aftertreatment system,” Gryglak said. “The reverse flow and inboard exhaust configuration helps us achieve all of those objectives. It’s a smarter design.”
New aluminum cylinder heads replace cast iron to save weight. They feature dual water jackets for cooling and a six-bolt attachment pattern for extra strength. Note the asymmetrical sizes and layouts of the intake (larger) and exhaust (smaller) ports.
Why? The arrangement dramatically shortens the distance between the exhaust and turbo, improving turbo response while protecting nearby powertrain components, like the fuel pump and alternator, from excessive heat. Higher turbo outlet temps also provide extra heat to downstream emissions devices to improve pollution-scrubbing performance sooner while emission catalysts (used to break down harmful pollutants) are warming up.
“Total exhaust volume and surface area of this configuration is about half that of the previous engine,” Gryglak said. “At the same time, we’ve been able to significantly improve the throttle feel of the truck.”
Single Sequential Turbo
Ford also reengineered the variable geometry turbo from the ground up with help from Honeywell’s Garrett Turbo Division (the same turbo supplier for the Duramax). As modern diesel mills like the 6.7-liter have become more powerful from generation to generation, emissions limits have gotten much tighter, and it’s become progressively difficult to match the turbo’s dual jobs of exhaust gas recirculation (EGR) with acceptable levels of responsiveness.
Instead of using two separate sequential turbochargers like the current 6.4-liter PSD, the new Single Sequential Turbocharger places two compressors back-to-back (right side of picture in blue, representing cool intake fed air) to create a twin turbo setup in a single package. The VGT turbo still uses a variable vane setup around the turbine (left side of picture in red, representing hot exhaust) that continually change the velocity of the exhaust gas and wheel speed.
EGR recirculates some of the engine's exhaust back into the engine at a lower temperature. The cooled gases have a higher heat capacity and contain less oxygen than air, lowering combustion temperatures and reducing the formation of NOx.
Multi-turbo systems, like the previous Borg Warner two-turbo sequential setup that the 6.4-liter PSD used, can overcome these issues but they also face problems in packaging and heat that wouldn’t work with the Scorpion’s new architecture.
“The turbo we’re using for the 6.7-liter engine is called a ‘Single Sequential Turbo,’” Gryglak said. “It’s a triple-wheel design with a single turbine and two compressors placed back-to-back. What we’ve done is take a twin-turbo configuration and package it into a single unit that gives us seamless transitions [as its adds boost throughout the RPM range and power band]. It also allows us to drive EGR at very low airflow rates to meet the new NOx regulations but also allows us to build the boost we need to overcome the pressure from the EGR.”
The Siamese compressor wheels are near-mirror images of each other. They have the same diameter and are optimized to reduce pressure differences that could cause noise or airflow issues. By packaging them as two smaller turbos, mass is also kept closer to the shaft which helps with balance and durability. The turbo is quicker to boost and better able to deliver horsepower and torque, especially at the low end where it’s needed most the help get heavy loads moving quickly.
External picture of the Power Stroke's new SST turbocharger.
The SST turbo continues to use variable vanes that surround the turbine wheel to dynamically adjust turbo speed using exhaust gases. During engine operation at low speeds and load, the vanes are closed to accelerate exhaust gases across the turbine wheel to help increase turbo wheel speed quickly. At high speeds the vanes are opened to help prevent the turbo overspeed. It's also been enhanced to introduce exhaust braking into the platform.
“You’ll get the feeling [when you’re driving in] tow/haul mode but it won’t explicitly be called exhaust braking. It’s built into the system,” Gryglak said.
The turbo also uses a brand new ball-bearing cartridge that surrounds the turbo shaft to help provide a double-digit increase in spool-up times.
Though some turbos are mounted to the engine off the turbine side – a solution that can cause balance issues requiring extra structural reinforcement and noises like whistles and whines – Ford balances the SST by mounting it at the turbo’s center using a 4-bolt pedestal housing. The compressor stage is bracketed back to the pedestal so it has an extremely stiff structure in front. Separate oil and water feeds flow through the pedestal to lubricate and cool the turbocharger and eliminate as many external connections as possible. The front of the pedestal houses the turbo’s oil filter.
The 6.7-liter SST provides up to around 30 psi boost compared to approximately 40 psi from the 6.4-liter dual-sequential unit and operates at up to 130,000 rpms.
Putting Their Money Where Their Mouths Are
Ford won’t say how much money it invested in the 6.7-liter Power Stroke diesel, but we think it may be the most expensive single engine program in the company’s history. Perhaps we’ll see more Scorpion derivatives to spread the investment among a larger group of vehicles.
Ford also isn’t talking about the prices when the engines go on sale in the 2011 Super Duty next year. We think it will run more than the current engine. But Ford does repeat over and over like a mantra: the 6.7-liter PSD will be the most powerful, most fuel-efficient and the most-refined Power Stroke diesel engine yet. And the team that created it says it will be around a long time.