As the official vehicle of the South, the Texas State Fair has become the prime venue for automakers to show off new pick-up trucks. In two weeks, Ford will use the fair to debut the 2011 Super-Duty range, which will receive the new 6.7-liter Power-Stroke (aka Scorpion) diesel V8. At a product briefing in Dearborn this week, Ford showed off the new engine and told us the updated big trucks would start production in the second quarter of 2010.
Ford also shared a few more details on the engine, but declined to reveal power and torque figures. However, we know a bit more about the new turbocharger, specifically the intake ducting feeding the turbo's inlets is designed to provide some passive flow control. Take a quick trip back to basic auto-shop class and you'll remember that the turbo has two smaller compressor wheels mounted back-to-back on a common shaft. At light load conditions, the shape of the inlet directs most of the flow to a single compressor. As the flow rate builds, it get redirected into the second compressor allowing more power to be produced. More after the jump.
One of the most important technical features of the new engine, aside from the inboard exhaust architecture, is the common rail fuel injection system. This Bosch supplied system uses third generation piezo-electric injectors and operates with fuel pressures of 30,000 psi. It's high pressure and precise pulse control allow the system to perform up to five individual injection pulses per power cycle. At idle, the system uses three pulses, two pilots and one primary pulse.
After showing us a cut-away of the engine, we were taken out to a garage where a prototype truck equipped with the new engine was sitting at idle. As we approached the truck it was remarkably quiet with none of the clatter that we've become accustomed to from big, oil-burning trucks. We stood next to the truck talking in normal voices, something that's all but impossible with the current Navistar supplied engine.
To demonstrate just how effective the multi-pulse control strategy is at reducing noise, an engineer switched the engine over to a traditional single pulse control map. All of a sudden, the traditional diesel was back with all of its racket. After a couple of minutes, the engine was switched back to the new control scheme. An equally impressive part of the demonstration came when the hood of the truck was opened. Surprisingly, no acoustic insulation was mounted on the underside of the hood. What we were hearing was un-damped noise and production Super-Duty diesels won't carry any sound insulation under the hood.
The 6.7-liter Power-Stroke is the first Ford diesel certified to run on B20 biodiesel. It turns out the only special changes that Ford had to make for biodiesel compatibility were new seals and a fuel pressure switch. The pressure switch detects when there is excessive fuel line pressure that may be caused by contaminated fuel.
in late 2007 and early 2008, as fuel prices began to climb up to their summertime peaks, the sales of Super-Duty diesels fell off precipitously. We asked Ford if they expect the new engine to help that situation and learned some interesting things from the discussion. The fall in diesel truck sales was largely attributed to a reduction in individual sales where the majority of buyers opt for diesels. Among fleet buyers, who previously picked up around 30 percent of Super-Dutys, diesels accounted for about 30 percent of sales and that largely held steady. The low share of diesels was due to fleets typically opting for lower purchase cost and didn't require towing.
However, the non-fleet individual purchasers needed trucks for towing and the vast majority went diesel. These were the same people who dropped out of the market when fuel prices skyrocketed taking the share of sales from 70 percent to about 50 percent. Ford expects these sales to recover somewhat as the economy and vehicle sales increase in the coming years and expects the efficiency and improved output of the Scorpion to help.