With the aim of improving the energy efficiency of conventional vehicles, this paper proposes a pneumatic hybrid engine concept, which features regenerative braking and compressed-air-assisted cranking functions. In the regenerative braking mode, the engine works as a two-stroke compressor and converts the kinematic energy of the vehicle into compressed air. In the two-stroke air motor mode, a throttle valve in the intake manifold is used to block the ambient air, and an electropneumatic solenoid valve is employed to control the compressed-air injection. The compressor mode is modelled on the basis of thermodynamics and gas dynamics theories and is improved according to the bench test results of a single-cylinder engine converted from a two-cylinder diesel engine. Transient engine cranking tests are also conducted and are discussed. Urban driving-cycle simulation results show that the fuel consumption of a light-duty vehicle with a pneumatic hybrid system can be reduced by 8%.
EhsaniMGaoYEmadiA. Modern electric, hybrid electric and fuel cell vehicles: fundamentals, theory, and design. 2nd edition. Boca Raton, Florida: CRC Press, 2010, pp. 385–413.
2.
CrossDBrockbankC. Mechanical hybrid system comprising a flywheel and CVT for motorsport and mainstream automotive applications. SAE paper 2009-01-1312, 2009.
3.
WuBLinCCFilipiZ. Optimal power management for a hydraulic hybrid delivery truck. Veh System Dynamics2004; 42(1–2): 23–40.
4.
SchechterMM. New cycles for automobile engines. SAE paper 1999-01-0623, 1999.
5.
HigelinPCharletAChamaillardY. Thermodynamic simulation of a hybrid pneumatic-combustion engine concept. Int J Appl Thermodynamics2002; 5(1): 1–11.
6.
TrajkovicSTunestalPJohanssonB. Vehicle driving cycle simulation of a pneumatic hybrid bus based on experimental engine measurements. SAE paper 2010-01-0825, 2010.
7.
DönitzCVasileIOnderC. Realizing a concept for high efficiency and excellent driveability: the downsized and supercharged hybrid pneumatic engine. SAE paper 2009-01-1326, 2009.
8.
ChenPLYuXLNieXH. Control strategy for parallel hybrid air–fuel vehicle (in Chinese). J Zhejiang Univ (Engng Sci)2011; 45(2): 348–353.
9.
LiuL. Optimization study on working process and key components of air powered engine (in Chinese). PhD Thesis, Zhejiang University, Hangzhou, People’s Republic of China, 2007.
10.
SchechterMM. Regenerative compression braking – a low cost alternative to electric hybrids. SAE paper 2000-01-1025, 2000.
11.
HigelinPVasileICharletA. Parametric optimization of a new hybrid pneumatic-combustion engine concept. Int J Engine Res2004; 5(2): 205–217.
12.
TaiCTsaoTCLevinMB. Using camless valvetrain for air hybrid optimization. SAE paper 2003-01-0038, 2003.
13.
KangHTaiCSmithE. Demonstration of air-power-assist (APA) engine technology for clean combustion and direct energy recovery in heavy duty application. SAE paper 2008-01-1197, 2008.
14.
WangXYTsaoTCTaiC. Modeling of compressed air hybrid operation for a heavy duty diesel engine. Trans ASME, J Engng Gas Turbines Power2009; 131(5): 052802-1–052802-8.
15.
BasbousTYounesRIlincaA. Fuel consumption evaluation of an optimized new hybrid pneumatic-combustion vehicle engine on several driving cycles. Int J Engine Res2012; 13(3): 253–273.
16.
DönitzCVoserCVasileI. Validation of the fuel saving potential of downsized and supercharged hybrid pneumatic engines using vehicle emulation experiments. Trans ASME, J Engng Gas Turbines Power2011; 133(9): 092801-1–092801-13.
17.
ZhaoHPsanisCMaT. Theoretical and experimental studies of air-hybrid engine operation with fully variable valve actuation. Int J Engine Res2011; 12(6): 527–548.
18.
TurnerJWGBassettMDPearsonRJ. New operating strategies afforded by fully variable valve trains. SAE paper 2004-01-1386, 2004.
19.
ChenPLYuXLLiuL. Simulation and experimental study of electro-pneumatic valve used in air-powered engine. J Zhejiang Univ Sci A2009; 10(3): 377–383.
20.
LiDFWangLYeJ. Valve strategy design for braking energy regeneration through engine air compression. In: 2012 international conference on advanced vehicle technologies and integration, Changchun, People’s Republic of China, 16’19 July 2012, pp. 508–514. Beijing: China Machine Press.
21.
LeeCYZhaoHMaT. A simple and efficient mild air hybrid engine concept and its performance analysis. Proc IMechE Part D: J Automobile Engineering2012; 227(1): 120–136.
22.
FazeliA. Development of a novel air hybrid engine. PhD Thesis, University of Waterloo, Waterloo, Ontario, Canada, 2011.
23.
InoueKNagahiroKAjikiY. A high power, wide torque range, efficient engine with a newly developed variablea-valve-lift and-timing mechanism. SAE paper 890675, 1989.
24.
BrüstleCSchwarzenthalD. The “two-in-one” engine – Porsche’s variable valve system (VVS). SAE paper 980766, 1998.
25.
YuXLDouWBChenJX. Stroke variable pneumatic hybrid engine and its operating method (in Chinese). China Invention Patent 201410588012.0, 2014.
26.
HuJQYuXLNieXH. Feasibility of parallel airpowered and diesel hybrid engine (in Chinese). J Zhejiang Univ (Eng Sci)2009; 43(9): 1632–1637.
27.
GT-SUITE flow theory manual, version 7.0. Westmont, IL: Gamma Technologies, 2009.
