Labels:text | screenshot | font OCR: Many modern automobiles knock occasionally, particularly under low speed, heavy load conditions because the manufacturers have had to deal with the conflicting requirements of high fuel efficiency and low available fuel octane resulting from the limited amount of "lead" and other additives that are now allowed in automobile fuel by the U.S. Environmental Protection Agency. The efficiency of gas engines, (10-25%) is therefore limited by the maximum compression ratio possible with available fuel, and this compression ratio is always much less than a diesel. This is one of the reasons the gas engine is less efficient than the diesel. A much more important difference in efficiency occurs at part load and idle. Here, with the gas engine, the fuel air mixture is drawn through a partially closed ...
