Exploring the Advantages of Variable Compression Ratio in Internal Combustion Engines by Using Engine Performance Simulations

2011 ◽  
Author(s):  
Alberto Boretti ◽  
Joseph Scalzo
Keyword(s):  
Compression Ratio ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Variable Compression Ratio ◽  
Variable Compression

scholarly journals Temperature, Heat Distribution and Performance Analysis in a Variable Compression Ratio Internal Combustion Engine

2020 ◽  
Vol 8 (5) ◽  
pp. 4825-4829
Keyword(s):  
Heat Loss ◽  
Compression Ratio ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Cooling Water ◽  
Internal Combustion ◽  
Heat Distribution ◽  
Variable Compression Ratio ◽  
Variable Compression

The internal combustion engines are also known as heat engines because of the utilization of heat energy of the fuel to convert it in to mechanical energy of the engine which finally runs the vehicle. Therefore, it is necessary to examine the generation and utilization of heat inside and outside the engine. For the above mentioned purpose, a variable compression ratio engine was used to perform experiment. The heat distribution of the used engine was investigated to recognize the heat loss areas from the engine. The experiments were performed by changing compression ratio from 15 to 21 and an optimum compression ratio was found. The experiments are further extended to find an optimum load value at standard compression ratio of the engine. The analysis was performed by using various factor of heat utilization such as heat supplied by fuel, heat equivalent to brake power, heat loss to exhaust gases, heat loss to engine cooling water and heat unaccounted. The proposed research will be useful to overcome the challenges during selection of compression ratio for design of an engine in industries.

scholarly journals Determination of Combustion Process Model Parameters in Diesel Engine with Variable Compression Ratio

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Saša Milojević ◽  
Radivoje Pešić
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Process Model ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Model Parameters ◽  
Connecting Rod ◽  
Variable Compression Ratio ◽  
Variable Compression

Compression ratio has very important influence on fuel economy, emission, and other performances of internal combustion engines. Application of variable compression ratio in diesel engines has a number of benefits, such as limiting maximal in cylinder pressure and extended field of the optimal operating regime to the prime requirements: consumption, power, emission, noise, and multifuel capability. The manuscript presents also the patented mechanism for automatic change engine compression ratio with two-piece connecting rod. Beside experimental research, modeling of combustion process of diesel engine with direct injection has been performed. The basic problem, selection of the parameters in double Vibe function used for modeling the diesel engine combustion process, also performed for different compression ratio values. The optimal compression ratio value was defined regarding minimal fuel consumption and exhaust emission. For this purpose the test bench in the Laboratory for Engines of the Faculty of Engineering, University of Kragujevac, is brought into operation.

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.

Optimization of the Charge Motion in Internal Combustion Engines Driven by Sewage Gas for CHP-Units

2017 ◽  
Author(s):  
Lucas Konstantinoff ◽  
Lukas Möltner ◽  
Martin Pillei ◽  
Thomas Steiner ◽  
Thomas Dornauer ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Engine Performance ◽  
Internal Combustion ◽  
Optical Methods ◽  
Combustion Engines ◽  
Charge Motion ◽  
Combustion Analysis ◽  
Valve Seat ◽  
Test Engine ◽  
Indication System

In this study, the influence of the charge motion on the internal combustion in a spark ignition sewage gas-driven engine (150 kW) for combined heat and power units was investigated. For this purpose, the geometry of the combustion chamber in the immediate vicinity to the inlet valve seats was modified. The geometrical modification measures were conducted iteratively by integrative determination of the swirl motion on a flow bench, by laser-optical methods and consecutively by combustion analysis on a test engine. Two different versions of cylinder heads were characterized by dimensionless flow and swirl numbers prior to testing their on-engine performance. Combustion analysis was conducted with a cylinder pressure indication system for partial and full load, meeting the mandatory NOx limit of 500 mg m−3. Subsuming the flow bench results, the new valve seat design has a significant enhancing impact on the swirl motion but it also leads to disadvantages concerning the volumetric efficiency. A comparative consideration of the combustion rate delivers that the increased swirl motion results in a faster combustion, hence in a higher efficiency. In summary, the geometrical modifications close to the valve seat result in increased turbulence intensity. It was proven that this intensification raises the ratio of efficiency by 1.6%.

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.

scholarly journals Camshaftless Technology on Internal Engines

2020 ◽  
Vol 5 (2) ◽  
pp. 118-123
Author(s):  
Van Viet Pham
Keyword(s):  
Fuel Consumption ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Control Valve ◽  
Internal Combustion ◽  
Exhaust Valve ◽  
Combustion Engines ◽  
Toothed Belt ◽  
Significant Performance ◽  
Exhaust Valves

Along with the development of internal combustion engines, camshafts have also been developed to optimize engine performance. In all types of internal combustion engines, the crankshaft is connected to the camshaft via a toothed belt, chain or pinion. When the crankshaft turns, the camshaft spins and opens and closes the intake and exhaust valve respectively. However, in this non-camshaft engine technology, each intake and exhaust valve will be integrated with an electronically controlled hydraulic pump unit. This system provides a unique ability to independently control intake and exhaust valves. For any engine load, load and discharge times can be programmed independently. The decision system is based on driving conditions, used to maximize performance or minimize fuel consumption and emissions. This allows a greater degree of control over the engine which in turn provides significant performance benefits. This article presents reviews of camshaftless technology developed by VALEO. It is a system that uses solenoid valves to open and close the valve. The solenoid valve will be mounted right on top of the valve inside the engine. The author can see that the technology using this electronic control valve will help reduce the fuel consumption of the engine.

scholarly journals Thermodynamic modeling of combustion process of the internal combustion engines – an overview

2019 ◽  
Vol 178 (3) ◽  
pp. 27-37 ◽  
Author(s):  
Denys STEPANENKO ◽  
Zbigniew KNEBA
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Combustion Process ◽  
Engine Performance ◽  
Internal Combustion ◽  
Air Pollutant ◽  
Combustion Engines ◽  
Engine Simulation ◽  
Toxic Emissions ◽  
The Moment

The mathematical description of combustion process in the internal combustion engines is a very difficult task, due to the variety of phenomena that occurring in the engine from the moment when the fuel-air mixture ignites up to the moment when intake and exhaust valves beginning open. Modeling of the combustion process plays an important role in the engine simulation, which allows to predict in-cylinder pressure during the combustion, engine performance and environmental impact with high accuracy. The toxic emissions, which appears as a result of fuels combustion, are one of the main environmental problem and as a result the air pollutant regulations are increasingly stringent, what makes the investigation of the combustion process to be a relevant task.

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