The Evolution of the Gas Engine
- While some might argue that the concept of a steam engine actually dates back to Greek geometer Heron and his first-century AD aeolipile, the device itself wasn't suggested for use in performing real work until a man named Dionysius Papin published plans for a functional engine in 1690. When James Watt created the world's first successful steam engine in 1744, he created the mold for what we now know as the internal combustion engine. The first functioning gasoline engines date back not to Nikolaus Otto -- after whom the Otto cycle was named -- but to a man named Samuel Brown. Brown's "gas vacuum engine" was actually just an evolution of Watt's steam engine, one that used the force of burning gasoline instead of steam to motivate the pistons.
- The first commercial gasoline engines had to make do with the extremely low-octane fuels available at the time, which meant low compression ratios and a fairly dismal power output compared to engines 50 years later. High-octane ethanol fuel -- also known as "moonshine" -- was already around and saw some use at the turn of the century, but didn't see mainstream use in automobiles until the late 1930s. By then, manufacturers had already figured out how to produce high-octane aviation and automotive fuels. Once cars hit the mainstream, cylinder count started going up in an effort to improve smoothness and horsepower with a given displacement. Overhead-valve engines sent flat-head engines the way of the dodo bird during the early 1950s, and advanced port and combustion chamber designs -- notable the hemispherical or "hemi" chamber -- more than doubled average engine output from the 1930s through 1956 or so.
- If you're going to draw a line to divide eras in gas engine evolution, then the first one has to be when American Motors began offering a Bendix "Electrojector" electronic fuel injection system on its 1957 Rambler Rebel. While development gremlins limited 1957 model production to less than a dozen, the Rebel's Electrojector system migrated to Chrysler in 1958, and Bendix sold the system's patents to Bosch a few years later. From these patents, Bosch developed the D-Jetronic system, which set the template for all electronic fuel injection systems to come. In the early 1970s, a company named Per-Lux -- later Pertronix -- engineered an electronic ignition system as a retrofit for point-and-condenser distributors. One day, Pertronix was walking down the street eating a chocolate bar and ran into Bosch, who was inexplicably carrying an open jar of peanut butter. The result: a tasty combination that dominates the auto industry to this day.
- While Toyota made much ado about its 1997 hybrid Prius, it was hardly the first company to offer a hybrid drivetrain; Ferdinand Porsche engineered the first gas-electric hybrid way back in 1900. Various other companies spent the next century playing with the design, but we have Audi's 1989 C3 100 Avant Duo to thank for proving its viability in and readiness for mass-market sales. The first Duo was a flop, but the second iteration set a standard that Volvo -- in 1992 -- Toyota and other manufacturers would later follow. Since then, manufacturers have been focusing on ways to enhance engine efficiency through turbocharging, hybridization, variable cam timing, variable intake, exhaust tuning and other means to achieve a perfect balance of power, cleanliness and fuel economy.
- As of 2011, gasoline engines are poised to undergo another major revolution in the form of homogeneous charge compression ignition. Gas engines have never been able to match the low rpm torque and fuel efficiency of diesels, and they never will. The reason they never have is because of the diesel engine's inherent ability to get the most out of its fuel charge by compressing it to the point of ignition rather than igniting it with a spark. The reason they never will is that diesel fuel by definition contains more BTUs of energy per gallon than gasoline. However, the HCCI cycle will allow gas engines to get very close to the diesel's efficiency and torque by operating as a compression-ignition engine at low rpm and a more powerful spark-ignition engine at high rpm. Trust that HCCI is just over the horizon and on a hurricane-like course toward our shores. When combined with direct injection, turbocharging and more precise airflow-control methodologies, HCCI promises to deliver at least a 30 to 40 percent increase in fuel economy and -- when tuned for it -- a concordant increase in low rpm torque.
