Numerical Simulation of Gas Exchange Process in Two Stroke Reverse-Loop Scavenging Engines

2012 ◽  
Vol 468-471 ◽  
pp. 2259-2264 ◽  
Author(s):  
Qing Zhu ◽  
Zhao Cheng Yuan ◽  
Wen Cui Guo ◽  
Ying Xiao Yu
Keyword(s):  
Numerical Simulation ◽  
Diesel Engine ◽  
Gas Exchange ◽  
Structural Parameters ◽  
Exchange Process ◽  
Simplified Model ◽  
Structure Parameters ◽  
Free Piston ◽  
Main Structure ◽  
Gas Exchange Process

For developing free-piston diesel engine, The two stroke Reverse-Loop scavenging diesel engine E150 was taken as the prototype and a simplified model was built by using CATIA software. Based on the influence of different factors about the gas exchange process，several layouts of scavenging air belt to be built in different schemes. Then the influence of the main structure parameters of scavenging air belt to the gas exchange process were analyzed and a better scheme of structural parameters was obtained.

Stability Analysis of a Hydraulic Free Piston Engine With HCCI Combustion

2011 ◽  
Author(s):  
Ke Li ◽  
Zongxuan Sun
Keyword(s):  
Gas Exchange ◽  
Exchange Process ◽  
Dynamic Coupling ◽  
Free Piston ◽  
Operation Conditions ◽  
Hcci Combustion ◽  
Free Piston Engine ◽  
Current Cycle ◽  
The Stability ◽  
Gas Exchange Process

This paper analyzes the stability of the dynamic coupling among the homogeneous charge compression ignition (HCCI) combustion, gas exchange dynamics and the piston dynamics in a hydraulic free piston engine. The intrinsic feedback nature of the system makes the stability of the engine operation difficult to predict. Specifically, output from the gas exchange process of the previous cycle affects the combustion timing of the current cycle. The combustion force and hydraulic loading together determine how far the piston can travel (dead center positions) and provide input for the current cycle gas exchange process. A discrete cycle-to-cycle based model that captures this dynamic coupling is described in the paper. Linearization of the model gives us the insight of the engine stability under any given operation conditions. The stability analysis is validated with Matlab numerical simulation results of a high-order nonlinear model under a specified set of operation conditions. The proposed methodology can be transformed and applied to analyze stability of systems with similar dynamics couplings.

scholarly journals Investigation on the Effect of the Gas Exchange Process on the Diesel Engine Thermal Overload with Experimental Results

Energies ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. 766 ◽  
Author(s):  
Sangram Kishore Nanda ◽  
Boru Jia ◽  
Andrew Smallbone ◽  
Anthony Paul Roskilly
Keyword(s):  
Diesel Engine ◽  
Gas Exchange ◽  
Exchange Process ◽  
Experimental Results ◽  
Gas Exchange Process

Optimization of the Scavenging System Based on Specific Time-Area Value of a Compact Two-Stroke Gasoline Engine

2012 ◽  
Vol 538-541 ◽  
pp. 3094-3097
Author(s):  
Shou Chen Xing ◽  
Chen Hai Guo ◽  
Pu Kang Xie ◽  
Fei Dong
Keyword(s):  
Numerical Simulation ◽  
Optimal Design ◽  
Gas Exchange ◽  
Mathematical Models ◽  
Gasoline Engine ◽  
Exchange Process ◽  
Specific Time ◽  
Gas Exchange Process ◽  
Stroke Engine

The specific time-area values describe the circulating ability of two-stroke engine ports during the gas exchange process, so they are the main parameters to affect the engine performances [1]. This paper establishes mathematical models of port parameters for symmetrically timing ports of two-stroke gasoline engine with carburetor and crankcase loop scavenging, the emphasis of analysis is specific time-area values of the ports. The mathematical models of specific time-area values which introduced in this paper give the initiative for further research on the numerical simulation and the optimal design of two-stroke engine.

Experimental research on scavenging process of opposed-piston two-stroke gasoline engine based on tracer gas method

2021 ◽  
pp. 146808742110366
Author(s):  
Fukang Ma ◽  
Wei Yang ◽  
Yifang Wang ◽  
Junfeng Xu ◽  
Yufeng Li
Keyword(s):  
Gas Exchange ◽  
Exchange Process ◽  
Delivery Ratio ◽  
Tracer Gas ◽  
Piston Motion ◽  
Trapped Air ◽  
Exchange Performance ◽  
Gdi Engine ◽  
Gas Exchange Process ◽  
Scavenging Efficiency

The scavenging process of two stroke engine includes free exhaust, scavenging, and post intake process, which clears the burned gas in cylinder and suctions the fresh air for next cycle. The gas exchange process of Opposed-Piston Two-Stroke (OP2S) engine with gasoline direct injection (GDI) engine is a uniflow scavenging method between intake port and exhaust port. In order to investigate the characteristics of the gas exchange process in OP2S-GDI engine, a specific tracer gas method (TGM) was developed and the experiments were carried out to analyze the gas exchange performance under different intake and exhaust conditions and opposed-piston movement rule. The results show that gas exchange performance and trapped gas mass are significantly influenced by intake pressure and exhaust pressure. And it has a positive effect on the scavenging efficiency and the trapped air mass. Scavenging efficiency and trapped air mass are almost independent of pressure drop when the delivery ratio exceeds 1.4. Consequently, the delivery ratio ranges from 0.5 to 1.4 is chosen to achieve an optimization of steady running and minimum pump loss. The opposed piston motion phase difference only affects the scavenging timing. Scavenging performance is mainly influenced by scavenging timing and scavenging duration. With the increased phase difference of piston motion, the scavenging efficiency and delivery ratio increased gradually, the trapping efficiency would increase first and decrease then and reaches its maximum at 14°CA.

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