Study of a New Strategy for Pneumatic Actuator System Energy Efficiency Improvement via the Scroll Expander Technology

Feasibility Study of a Scroll Expander for Recycling Low-Pressure Exhaust Gas Energy from a Vehicle Gasoline Engine System

“…m is the air mass flow rate; V represents volume in general; V tol is the total control volume inside the scroll expander shell; P is air pressure; T is the air temperature; the initial point of the moving scroll is defined at the position (x 0 ,y 0 ); n s is the number of scroll wraps; ρ 0 is the initial radius of the curvature of the moving scroll curve; [X air ] represents the molar volumetric concentration of air; R is the ideal gas constant; M air is the molar mass of air; h is the specific enthalpy of the air on a molar basis; C p,air (T) refers to the specific heat of air at the temperature T; h stands for the air enthalpy; ω s is the scroll expander rotor angular speed; τ scroll is the shaft torque of the scroll expander; k refers to the slope of the curvature radius;P is pressure difference between the adjacent chambers of the scroll expander; r s is the radius of the orbit relevant to the moving scroll motion (for details, refer to [20]); α s stands for the current orbit angle of the moving scroll; z is the height of the two scrolls; K fs is defined as the coefficient of the scroll viscous friction; K S´C S(ω s ) stands for the combination effect on torque from the static and Coulomb frictions, and the detailed explanation of the scroll expander frictions was described in [20,23,27];…”

Energy Efficiency of Pneumatic Cylinder Control with Different Levels of Compressed Air Pressure and Clamping Cartridge

“…Kanno et al [12] developed a three-port poppet-type servo valve to reduce air leakage and to improve the energy efficiency of the whole pneumatic system. Many authors wereimproving the energy efficiency in the driven actuator and making the circuit more complex, such as using dual pressure supply, utilizing expansion energy [13], recovering energy with a rubber bladder and storing the strain energy [14], or reusing exhaust air for power generation [15]. In addition, reusing exhaust air as input to the drive chamber of the cylinder led to velocity fluctuations [16].…”

A New Scroll-Type Air Motor With Magnetic Spirals

“…The paper indicates that the leakage has a significant effect on the volumetric efficiency of the system. A hybrid pneumatic system that recovers energy from the exhaust air through a scroll expander was designed by Luo et al, which concluded that, with a proper closed-loop coordinate control strategy, the energy efficiency improvement can reach 18.1% from the tests [12]. Luo et al also studied a vehicle gasoline engine post-combustion mixture energy reusing system via the scroll technology [13].…”

“…From the above literature review, it can be found that, in many of the above designs/applications, scroll air motors (expanders) have been used as a prime mover to produce the driving torque for electrical generators [7,[12][13][14][15][16][17].…”