This got me thinking about the properties of energy transfer. The conservation of energy is a fundament of physics that states, in short: "Energy cannot be created or destroyed, only changed from one form to another." While energy apparently takes many forms, it can be divided into two main categories: potential energy and kinetic energy. The gasoline in your car's tank has potential energy. When ignited, its potential energy is transformed into the kinetic energies of heat and light (explosion). When detonated in the cylinders of an internal combustion engine, gasoline/oxygen mixtures release heat energy, excite interacting molecules, and force the pistons down, creating motion that is eventually transferred to the car's wheels. In the same ways an engine transfers energy to put a car in motion, brakes transfer energy to bring it to a stop, in that, through friction, they transfer the energy of the car in motion into heat energy that is dispersed through interaction with the air and surrounding matter.
Another crucial law of physics is Newton's First Law of Motion, which states: "Objects in motion stay in motion unless acted upon by another force." How this applies to our case with the car is that, in an ideal world, all of the potential energy held by the gasoline in a car's tank could be transferred to forward motion, and that once the car has stopped accelerating, it could maintain a constant speed infinitely. Such a complete transfer of energy is "100 percent efficient." Now, we know this can never be the case in the real world; a car in motion is eventually slowed to a stop by forces including wind resistance, gravity, friction and other factors that "leech" the energy of its motion. Likewise, an engine can never be completely efficient, since power generated during combustion is lost through the release of light, the heat that is absorbed by internals or expelled through exhaust. Some studies determine the average piston-powered, gasoline-burning car to be only 20 percent efficient-meaning 80 percent of the potential energy held by its gasoline is lost. Logically, the key to optimizing a vehicle's fuel efficiency is to limit the ways in which energy from combustion is misdirected from motion.
Applying this rationalization to my Integra, I determined there are many ways in which efficiency could be improved, but wondered how many would come without major inconvenience or influence on daily drivability. A conversation with a friend and fellow tuner Denis Howell of Hybrid Dynamics in Youngwood, Pa., brought up more ways than I had thought of to increase efficiency, and since a dyno was readily accessible, a controlled testing environment could be used for the most accurate results possible. We were well on our way to conducting a genuine experiment. Needless to say, we were psyched.
Thinking back to sixth-grade general science class (i.e. google.com) we made sure to follow the steps of the scientific method to ensure every precaution was taken for our experiment to produce consistent and reproducible results. Our question was: "Can a vehicle's efficiency be enhanced to improve both fuel economy and performance while maintaining reliability and practicality?"
Drawing on his knowledge of tuning cars and improving their performance, Howell assured there was room for improvement. In stock form, cars are heavier both in their rotational and static mass, which as we have already established, takes energy away from motion. Also from the factory, cars are tuned with slightly richer air/fuel ratios to provide a "buffer" for unforeseen stresses on engines, such as the use of low-grade fuels, towing excessive weight, driving in harsh climates and suffering mechanical problems, all of which can cause engine-killing detonation if cylinder temperatures climb too high. Stock air/fuel ratios can be leaned out to create power more efficiently, but at the risk of heightening propensities for detonation-risks that, if special care is taken, shouldn't cause problems. Doing my own research, I found that everything from driving habits, to tire pressure, and keeping up with regular maintenance could improve efficiency more than one might think. Our hypothesis was, simply, a "yes" to our question, at this point, but needed the establishment of a baseline before it could be narrowed further.
By Les Bidrawn
Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!