The ongoing dance around CAFE and EPA standards has created another example of mechanical Darwinism. Ethanol Boosting Systems, LLC, an engineering partner of Ford, has cross-bred a traditional gasoline engine with E85 Direct Injection and thrown in a couple of turbochargers for good measure. The resulting mutation provides diesel-like performance on demand with improved emissions and increased fuel economy. Code-named “Bobcat”, it could be the future of engines or the next vaporware coffee table in the engineering lounge. Why so cynical? Thank you for asking.
First of all, let’s start with some details. A recent presentation made by Ford to the Department of Energy and Society of Automotive Engineers detailed the most recent progress on their “DI Octane Boost” engine. Each cylinder of this small turbocharged engine has both gasoline and ethanol injectors. Gasoline mixes with air inside the intake manifold and is applied via typical port injection. At the same time, a very small amount of E85 is directly injected to cool the combustion chamber. This cooling of the air/fuel ratio suppresses knocking and allows higher compression ratios effectively increasing the octane of regular pump gas to more than 150 octane. Kiss my ass overpriced track fuel!
Under normal driving conditions, port-injected gas may be all that’s required. Direct injection E85 would apply in variable amounts to prevent knocking and to assist with heavier loads (insert your mom joke). The numbers don’t lie. According to Ford’s experiments, a 3.5L GTDI EcoBoost engine with E85 direct injection produced 553 lb-ft of torque and 316 hp at 3,000 rpm versus the 359 lb-ft and 300 hp for a standard EcoBoost at 4,500 rpm. Fuel efficiency should increase an average of 25 to 30 percent over the average port fuel injected engine with an incremetal cost of $1,500 at most.
Here’s where I play the old man that doesn’t like change. The engine requires two separate gas tanks for the two different fuels. A 5.0-liter Bobcat V-8 would use a 10 gallon E85 tank and a 26 gallon gas tank. This would require huge updates to our refueling infrastructure. Ford attempts to rationalize this concern with estimates of 20,000 mile increments between ethanol fill-ups under “mild driving conditions”. Could someone please find me a 5.0L V-8 owner that drives mildly for an entire 20,000 miles? On the flipside, under constant stress the E85 tank would need to be filled nearly every 100 miles.
The truth is this has been tried before. Some of you geezers may remember the 1962-1963 Oldsmobile F-85 Jetfire and its “Turbo-Rocket” engine. Using port injection and turbocharging proved to generate too much heat within the engine. The solution was to inject a blend of distilled water, methyl alcohol and rust inhibitor into the combustion chamber to absorb heat and reduce pinging. The solution was stored in an underhood reservoir. Unfortunately, a bunch of lazy asses would forget to refuel their “Turbo-Rocket Fluid” every 1,000 miles and the engine proved to be too troublesome and high-maintenance for the time.
Alas, by the time this technology hits the ground third and fourth generation electric hybrids will be getting all the press anyway.
More technical jargon here.