Inertial supercharging effect
The inertial supercharging effect is the increase of volumetric efficiency in the cylinder of an engine.[1]
Background
The internal combustion engine is the most common engine found in mechanical devices across the world. The engine is powered by an air/gasoline mixture and the physics principles of heat and pressure.[2]
What Exactly is happening?
Inertial supercharging effect is the result of incoming fuel/air charge developing momentum greater than intake stroke would generate alone. It is achieved by the careful design of the shape of the piston head, the valves and cam profile/valve timing which creates a vacuum that pulls more exhaust gases (and some of the intake gasses) out of the engine. This is immediately followed by a reflected pressure wave timed to force the extra intake gasses back into the cylinder, thus achieving a greater mass of air/fuel mix in the combustion chamber than possible with conventional methods. Expansion chambers only work well at a narrow engine speed range which is why two stroke engines are referred to as having a "powerband". Since the early 1980s exhaust powervalves have been developed which have the effect of altering the timing and/or volume of the expansion chamber, greatly improving the spread of power of high output two stroke engines.[3]
The idea behind this effect is that if more pressure is created within the cylinder, the faster the piston will be able to move.[1] The volumetric efficiency is maximized to increase the amount of air/fuel mixture in the cylinder during each cycle.[4] In turn, a greater air/fuel mixture in a cylinder will create a greater pressure therefore exerting a greater force on the piston. This increased force on each individual piston increases the potential horsepower of the entire engine.[5] The timing of the opening and closing of the valves is essential to ensure the air in the cylinder is maximized to create the most power in each cycle.[6]
References
- "Inertia Supercharging Air Flow Optimization - Aircraft Engine Overhaul". www.victor-aviation.com. Retrieved 2019-03-25.
- "HowStuffWorks". Choice Reviews Online. 45 (3): 45–1203–45-1203. 2007-11-01. doi:10.5860/choice.45-1203. ISSN 0009-4978.
- P.W Performance Aust.
- Bohacz, Ray T. “Forced Induction .” Hemmings.com, May 2015, www.hemmings.com/magazine/hcc/2015/05/Forced-Induction/3748512.html.
- Hu, Bo; Turner, James WG; Akehurst, Sam; Brace, Chris; Copeland, Colin (March 2017). "Observations on and potential trends for mechanically supercharging a downsized passenger car engine:a review". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 231 (4): 435–456. doi:10.1177/0954407016636971. ISSN 0954-4070.
- Policy, Privacy (2016-04-15). "Valve Timing Events and the Order of Importance". Engine Builder Magazine. Retrieved 2019-03-25.
- “Timing Is Everything .” Magnaflux Inspection - Aircraft Engine Overhaul, Victor Aviation Services, www.victor-aviation.com/Inertia_Supercharging_AirFlow_Optimization.ph
- Brain, Marshall, and Kristen Hall Geisler. “How Car Engines Work.” HowStuffWorks, 5 Apr. 2000, auto.howstuffworks.com/engine1.htm
- P.W. Performance Exhaust
- Bohacz, Ray T. “Forced Induction .” Hemmings.com, May 2015, www.hemmings.com/magazine/hcc/2015/05/Forced-Induction/3748512.html.
- Hu, Bo, et al. “Observations on and Potential Trends for Mechanically Supercharging a Downsized Passenger Car Engine:a Review.” Journal of Research in Crime and Delinquency, 6 Apr. 2016, journals.sagepub.com/doi/full/10.1177/0954407016636971.
- Kertes, Rick. “Valve Timing Events and the Order of Importance.” Engine Builder Magazine, 19 Apr. 2017, www.enginebuildermag.com/2016/04/valve-timing-events-and-the-order-of-importance/.