Labels:text | screenshot | font OCR: At idle or no load, the engine must again pump air into itself against the closed throttle, and then pump it back out on the exhaust stroke against atmospheric pressure, since the cylinder pressure is less than atmospheric at the end of the "power" stroke. This is good if you are interested in engine braking, but not good if you are waiting at a red light. SUPERCHARGER The best strategy to increase the fuel economy of a gas powered vehicle, therefore, is to use the smallest possible engine that will do the job. That way it will be near full throttle most of the time (for best efficiency), and when at part load or idle it will waste the minimum fuel because of its relatively small displacement. Another method for reducing part load and idle fuel consumption is to use an exhaust driven turbo ...
