scholarly journals Study on the Dynamic Characteristics of a Hydraulic Continuous Variable Compression Ratio System

2019 ◽  
Vol 9 (21) ◽  
pp. 4484 ◽  
Author(s):  
Chen ◽  
Wang ◽  
Liu ◽  
Yang
Keyword(s):  
Dynamic Characteristics ◽  
Compression Ratio ◽  
Hydraulic System ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Fast Response ◽  
Continuous Variable ◽  
Variable Compression Ratio ◽  
Bottom Dead Center ◽  
Variable Compression

Variable compression ratio (VCR) technology has long been recognized as a method for improving the engine performance, efficiency, and fuel economy of automobiles, with reduced emissions. In this paper, a novel hydraulic continuous VCR system based on the principle of an adjustable hydraulic volume is introduced. The continuous variable compression ratio of the VCR system is realized by the hydraulic system controlling the rotation of the eccentric pin to change the positions of the top dead center (TDC) and the bottom dead center (BDC). The construction of the mathematical model and simulation model of the VCR system is also presented in this paper. The piston motion characteristics, flow characteristics, and pressure characteristics of the hydraulic system of the VCR system at different engine speeds and adjustment quantities are studied by simulation in this paper. The simulation results show that the VCR system has a fast response and good dynamic characteristics, and can achieve continuous adjustment of the compression ratio.

Variable Compression Ratio Diesel Engine Performance Analysis

2015 ◽  
Vol 28 (1) ◽  
pp. 6-12 ◽  
Author(s):  
K.Satya narayana ◽  
◽  
Vinodh Kumar Padala ◽  
T.V.Hanumantha Rao ◽  
S.V.Umamahe swararao
Keyword(s):  
Diesel Engine ◽  
Performance Analysis ◽  
Compression Ratio ◽  
Engine Performance ◽  
Variable Compression Ratio ◽  
Variable Compression

A Theoretical Study of a Variable Compression Ratio Turbocharged Diesel Engine

1992 ◽  
Vol 206 (4) ◽  
pp. 227-238 ◽  
Author(s):  
T J Rychter ◽  
A Teodorczyk ◽  
C R Stone ◽  
H J Leonard ◽  
N Ladommatos ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Engine Performance ◽  
Expansion Ratio ◽  
Combustion Noise ◽  
Connecting Rod ◽  
Turbocharged Diesel Engine ◽  
Variable Compression Ratio ◽  
Engine Simulation ◽  
Variable Compression

A variable compression ratio concept that can give a different expansion ratio to the compression ratio has been evaluated by means of a simulation of a turbocharged diesel engine. The compression ratio is controlled by varying the ratio of the connecting rod length to the crank throw, hence the name variable crank radius/connecting rod length engine (VR/LE). The VR/LE mechanism kinematics have been defined and described, and the compression ratio and expansion ratio have been presented as a function of the eccentric phase angle (αo). A zero-dimensional engine simulation that has been the subject of comprehensive validation has been used as the basis of the VR/LE study. The effect of the compression ratio on the engine performance at fixed loads is presented. The principal benefits are a reduction in fuel consumption at part load of about 2 per cent and a reduction in ignition delay that leads to an estimated 6 dB reduction in combustion noise. The study has been conducted within the assumption of a maximum cylinder pressure of 160 bar.

Emulsified nano Al2O3 – Jatropha methyl ester blends: application in variable compression ratio engine

2020 ◽  
Vol 17 (5) ◽  
pp. 733-737
Author(s):  
Chiranjeeva Rao Seela ◽  
Ravi Sankar B.
Keyword(s):  
Diesel Engine ◽  
Methyl Ester ◽  
Compression Ratio ◽  
Engine Performance ◽  
Variable Compression Ratio ◽  
Content Type ◽  
Performance And Emission ◽  
Performance And Emissions ◽  
Improved Performance ◽  
Variable Compression

Purpose The purpose of this paper is to assess the influence of blends of Jatropha methyl ester (JME) and its nano Al2O3 emulsion on variable compression ratio diesel engine. The oxygen in alumina contributed for the smooth burning and resulted in improved performance and emissions. Design/Methodology/Approach The biodiesel (methyl ester) is prepared from the raw Jatropha oil. The B10, B20 and B30 blends of and their nanoemulsions are prepared with the 25, 50, 75 and 100 ppm of nano Al2O3. The prepared JME blends and its nanoemulsions are tested in a variable compression ratio (VCR) diesel engine to evaluate the engine performance and emission characteristics. Findings The nanoemulsion B20 + 50 ppm has given maximum brake thermal efficiency (BTE), and with the increased proportion of nanoparticle, the BTE was reduced. Also, the specific fuel consumption is lowest (0.2826 kg/kWh) for B20 + 50 ppm at the compression ratio 16.5 and full load which is 4.10% lower than the diesel and 5.8% lower than the B20 blend. As the load increases, NOx emission increases owing to higher peak temperatures in the combustion chamber. The JME-nano Al2O3 emulsion reduces the HC and CO emission compared with all other fuels. Originality/Value Novel nano emulsions are prepared, characterized and tested on VCR engine.

scholarly journals Research on a prototype spark ignition (SI) variable compression ratio engine fitted with a pneumatic energy accumulator

2014 ◽  
Vol 159 (4) ◽  
pp. 54-65
Author(s):  
Przemysław ŁAZIŃSKI ◽  
Michał GŁOGOWSKI ◽  
Jacek LEYKO
Keyword(s):  
Compression Ratio ◽  
Engine Performance ◽  
Machine Design ◽  
Maximum Pressure ◽  
Engine Operation ◽  
Variable Compression Ratio ◽  
University Of Technology ◽  
Operation Stability ◽  
Variable Compression Ratio Engine ◽  
Variable Compression

The paper describes investigations performed on a prototype variable compression ratio engine fitted with a pneumatic energy accumulator. The engine was built in the Chair of Vehicles and Basics of Machine Design at Lodz University of Technology. Due to the design and principle of operation, the engine may be an alternative to the already existing VCR engines. The pneumatic energy accumulator fitted in the cylinder head with an additional moving piston allows continuous adjustment of the compression ratio. The system is adaptive and adjusts itself to the engine load, reducing the increment of maximum pressure inside the cylinder. The research focuses on the influence of adjustment parameters of the energy accumulator on the movement of the additional piston and engine performance. Engine operation stability and reproducibility of the cycles has also been investigated. An attempt was made to characterize the engine and the energy accumulator in terms of efficiency and range of applicability (profitability of application).

A Study of a Multiple-link Variable Compression Ratio System for Improving Engine Performance

2006 ◽  
Author(s):  
Ryosuke Hiyoshi ◽  
Shunichi Aoyama ◽  
Shinichi Takemura ◽  
Kenshi Ushijima ◽  
Takanobu Sugiyama
Keyword(s):  
Compression Ratio ◽  
Engine Performance ◽  
Variable Compression Ratio ◽  
Link Variable ◽  
Variable Compression
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