Modern Aircraft Reciprocating Engines

Advancements in Aircraft Reciprocating Engines

Unlike the automotive industry, the aviation industry faces innovative criticism, with a lot of aeronautical experts under pressure to come up with technological advancements, to match the fast-paced growth of the automotive industry. The last decade has seen steps being made in the development of aircraft reciprocating engines. Recent versions of aircraft reciprocating engines have better build quality that has improved durability. Manufacturers have also perfected the engine's fuel delivery system and introduced advanced coatings to many of its components. The most significant breakthrough is the ability to connect these engines to advanced aviation-grade computers, capable of monitoring a variety of engine related parameters. Another advancement is in the turbocharger technology.

Improved Machining and Full-Authority Digital Engine Controls (FADEC)

With modern machining, companies, such as Continental now produce engines with less tolerance. The engines also employ full-authority digital engine controls, also known as Fadec. Although Fadec has been around for decades, recent technological advancements have made Fadec better. The technologies provide full electronic engine ignition, engine management functions able to monitor all parameters while at the same time digitally controlling fuel flow without a pilot's input. Technological advancements have also improved the engine's fuel delivery systems (Muqeem, Ahmad, & Sherwani 2015). The Fadec systems electronically control sparks and fuel injection, which ensures optimum performance at all times. The Lycoming iE2 Fadec technology, for instance, can control fuel delivery with higher constant pressure, allowing the pilot to manage the fuel delivery to each cylinder, a move previously impossible. Apart from better engine optimization, the technology optimizes leaning on each cylinder, to get maximum efficiency and performance in all conditions. For weight conservations, several engine covers are now built using magnesium, making the engines lighter than their predecessors.

Enhanced Turbocharging System and Fuel Efficiency

The modern aircraft reciprocating engine has a better turbocharging system. Older turbos have manually adjusted waste gates and fixed wastegates, which heavily relied on the pilot to monitor the boost pressure, and adjust the wastegates to avoid overboosting the engine. Today new technology allows for automatic wastegates, making turbocharging automatic, and hence more reliable at higher altitudes (Pan, He, Guo, Zhao, & Yang 2013). Current turbochargers can operate reliably and continuously with higher exhaust gas temperatures. To reduce fuel consumption, engineers have come up with new engine models. Such model is the Continental Motor's turbocharged, direct-injection TD300. The model is an engine able to run on alternative fuels and Jet-A. The diesel engine is already very efficient, but this new development makes the new engine 50% more efficient than gasoline powered piston engines (Pan, He, Guo, Zhao, & Yang 2013). Engineers have also redesigned piston arrangements in the engine to improve efficiency.

Innovative Cylinder Design and Emission Improvements

Unlike a conventional aircraft reciprocating engine, with a piston moving inside a cylinder and compressing air and fuel against a cylinder head, new models put two pistons in the same cylinder, thus eliminating the cylinder head. This new technology allows the two pistons to compress fuel and air between them (Wujciów & Gorniak, 2017). By using this design in four-cylinder engines, these engines can produce enough energy from small amounts of fuel as compared to the previous models. The design of an engine can significantly improve emissions. Recent studies and research show that by altering the shape of the combustion chamber and improving fuel injection can improve emissions by 25% (Thanikasalam et al., 2018). With the ability of many engines to run on alternative fuels, such as jet fuel, there is a significant improvement in emissions.

References

Muqeem, M., Ahmad, M., & Sherwani, A. (2015). Turbocharging of diesel engine for improving performance and exhaust emissions.: A review. IOSR Journal of Mechanical & Civil Engineering, 12(4), 22-29.

Pan, Z., He, Q., Guo, Y., Zhao, Y., & Yang, J. (2013). Research on the turbocharger technology of piston aircraft engine. Applied Mechanics & Materials, 457, 531-535.

Thanikasalam, K., Rahmat, M., Fahmi, G., Zulkifli, A., Shawal, N., Ilanchelvi, K., Ananth, M., & Elayarasan, R. (2018). Emissions of piston engine aircraft using aviation gasoline (avgas) and motor gasoline as fuel- a review. Journal of Transportation Engineering, 120 (3), 339-357.

Wujciów, Ł., Żurawski, R., & Górniak, T. (2017). Problems in designing fuel installation for small turboprop aircraft. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 231(12), 2228–2238