PUMPS

摘要

Engines are air pumps, identical in concept to gas-station air compressors but much more efficient because of the years of refinement lavished upon them by airflow specialists armed with flow benches. A brake master cylinder is a pump. Bike engines have oil and, usually, water pumps. Racing engines may have oversize oil scavenge pumps to evacuate their crankcases, saving power that would otherwise be wasted in pumping loss. Superchargers and turbo-chargers are pumps. The crankcases of two-stroke engines are used as fresh-charge pumps. Sound waves moving in intake or exhaust pipes pump air in or exhaust gas out. Lots of pumps. Lots of pumping going on.