Performance improvement of a two-stage GM cryocooler by use of Er(Ni0.075Co0.925)2 magnetic regenerator material

Abstract The present research concentrates on the performance improvement of a two-stage proportional valve with internal hydraulic position feedback which is named as the Valvistor valve. In this paper, the performance constraint of this valve is identified and a novel electronic closed-loop control strategy with an integral-separation fuzzy proportional-integral-derivative controller is proposed to improve the valve performance, including the static characteristics and the dynamic characteristics. The results show that in the Valvistor valve, the comparison point and the feedback loop for the internal hydraulic position feedback is only in the main stage, while the input is in the pilot stage. This leads to the poor performance of this valve. The control strategy is very effective and the performance of the Valvistor valve is improved. With the control strategy, the error of the poppet displacement is reduced from 4.9% to 2.1% by adjusting the spool displacement in the pilot stage in real-time and the flow error is reduced from 5.3% to 2.3%. The dead zone of the poppet displacement and the flow is eliminated. The hysteresis is reduced from 5.3% to 2.6% and the linearity is improved. The overshoot is reduced from 0.06 to 0.02 mm and the settling time is reduced from 0.5 to 0.2 s. Moreover, the bandwidth is increased from 8 to 16 Hz.

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APPLICATION OF NOVEL REGENERATOR MATERIAL WITHIN A COAXIAL TWO-STAGE PULSE TUBE REFRIGERATOR

10.1063/1.2908552 ◽

2008 ◽

Author(s):

T. Koettig ◽

F. Richter ◽

R. Nawrodt ◽

A. Zimmer ◽

C. Schwarz ◽

...

Keyword(s):

Pulse Tube ◽

Two Stage ◽

Pulse Tube Refrigerator ◽

Regenerator Material

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Performance improvement of two-stage serial organic Rankine cycle (TSORC) driven by dual-level heat sources of geothermal energy coupled with solar energy

Geothermics ◽

10.1016/j.geothermics.2018.07.010 ◽

2018 ◽

Vol 76 ◽

pp. 261-270 ◽

Cited By ~ 6

Author(s):

Tailu Li ◽

Xiaoxiao Hu ◽

Jianqiang Wang ◽

Xiangfei Kong ◽

Jian Liu ◽

...

Keyword(s):

Solar Energy ◽

Performance Improvement ◽

Geothermal Energy ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Heat Sources ◽

Two Stage

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Dynamic modeling and damping performance improvement of two stage ISD suspension system

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/09544070211059955 ◽

2021 ◽

pp. 095440702110599

Author(s):

Fanjie Li ◽

Xiaopeng Li ◽

Dongyang Shang ◽

Zhenghao Wang

Keyword(s):

Performance Improvement ◽

Ride Comfort ◽

Excitation Amplitude ◽

Random Excitation ◽

Suspension System ◽

Vehicle Suspension ◽

Vehicle Speed ◽

Two Stage ◽

Vehicle System ◽

Vehicle Suspension System

In this paper, the dynamics of the vehicle suspension system under the random excitation and the periodic excitation are investigated. To improve the damping performance of the vehicle suspension system, a two stage ISD suspension with “Inerter-Spring-Damper” in each stage is proposed based on electromechanical similarity theory. A vehicle dynamic model with two stage ISD suspension is established in this paper. The dynamic equation is solved by the Runge-Kutta method and the dynamic response of the whole vehicle system is obtained. Taking the traditional suspension as the comparison object, the dynamic characteristics of the system under random excitation and periodic excitation are studied in the time domain, and the suppression effect of the suspension designed in this paper on the resonance peak is verified in the frequency domain. The influence of the inertia coefficient on the damping performance of the vehicle suspension system is analyzed. The effects of excitation amplitude and vehicle speed on ride comfort improvement of vehicle system with two stage ISD suspension are discussed respectively. The results show that, the resonance peak values of body acceleration, dynamic travel of rear suspension and rear tire dynamic load frequency response are reduced by 59.1%, 21.6%, and 60.3% respectively. With the increase of excitation amplitude in the range of 0.02–0.04 m, the ride comfort improvement of two stage ISD suspension system is always more than 61%. With the increase of vehicle speed in the range of 10–25m/s, the performance improvement rate of two stage ISD suspension system can reach more than 34.1%.

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