The rapid rise in demand for smaller block, yet highly turbocharged, light-truck engines is providing potentially fertile new ground for the ethanol fuel industry, largely because such engine platforms are more efficient and can thus eliminate ethanol’s fuel economy penalty.
“The use of E-85 (a blended fuel containing 85% ethanol and 15% gasoline) in ‘flex-fuel’ vehicles has been limited by its 25% lower energy content than gasoline. When used in engines designed for only gasoline this results in approximately 25% less mileage for a fuel that costs as much as gasoline,” explained Robert “Bob” Kozak, president of Atlantic Biomass Conversions.
However, that fuel mileage discrepancy can be eliminated by engines such asMotor Co.’s EcoBoost – a twin-turbocharged V6 platform – as they are a more efficient match for ethanol’s higher octane rating.
“Such engine designs tap into the positive ability of ethanol to resist early ignition, thus regaining much of the previous fuel economy loss,” Kozak explained in an interview with Fleet Owner. “Higher octane ethanol makes an internal combustion engine operate more efficiently – up in the 30% to even 40% range – while it’s also priced lower than gasoline, on the order of 10 to 15%, because of its lower Btu or energy content.”
Also, these engine designs produce increased low-speed power or torque when using E-85, which could also allow lower-cost E-85 engines to compete more aggressively with pricier diesel platforms in the light-duty truck market, he noted in a white paper written for the nonprofit group Advanced Biofuels USA.
“It is very important to realize that this market would be a sustainable, rather than an artificial, market since it would be based on vehicles having equal or superior performance characteristics to gasoline or diesel powered vehicles,” Kozak pointed out.
Rod Beazley, director of the spark ignited engines product group at Ricardo plc, noted during a recent presentation at the Biofuels International conference in Calgary, Canada, that based on tests conducted with the firm’s ethanol boosted direct injection (EBDI) engine platform, equal mileage per gallon can be achieved when burning E-85 ethanol compared to gasoline – and would cost less than engines designed to meet the tougher mileage rates that were being introduced in the U.S.
Beazley explained at the conference that octane numbers measure a fuel’s ability to tolerate compression before detonating. The higher compression, he said, the higher efficiency of the engine in translating energy to power – meaning ethanol’s 110 octane rating, compared to the average 87 to 91 octane rating for gasoline – means ethanol can withstand compression rates more associated with diesel engines.
He also noted that direct injection, as a technology, allows for smaller engines to provide similar vehicle performance to that of larger block platforms – which is why Ford’s V6 EcoBoost provides the same power output as a traditional V8 in the F-150 pickup, yet with better fuel economy.
Ford noted in its September sales announcement that V6 engines continue to outsell V8s among its F-150 models, with the new 3.5L EcoBoost and 3.7L V6 engines representing 57% of F-150 retail sales in September.
Yet Atlantic’s Kozak cautioned that these new engine platforms still need to be “optimized” in order to maximize fuel efficiency with ethanol.
“Ford’s EcoBoost is a good first step, but Ricardo’s design is what’s really needed for E-85 to gain fuel economy parity with gasoline,” he noted. “But the point is these new engine designs combined with ethanol as a fuel could really make sense for everyone, but especially for fleets, by driving down fuel costs while increasing fuel economy.”