Effects of octane sensitivity on knocking combustion under modern SI engine operating conditions

2020 ◽  
Author(s):  
Xumin Zhao ◽  
Hu Wang ◽  
Daojian Liu ◽  
Zunqing Zheng ◽  
Mingfa Yao
Keyword(s):  
Operating Conditions ◽  
Si Engine

scholarly journals Determining the environmental indicators for vehicles of different categories in relation to CO2 emission based on road tests

2017 ◽  
Vol 170 (3) ◽  
pp. 66-72
Author(s):  
Jerzy MERKISZ ◽  
Łukasz RYMANIAK
Keyword(s):  
Co2 Emissions ◽  
Operating Time ◽  
Environmental Indicators ◽  
Operating Conditions ◽  
Si Engine ◽  
Propulsion Systems ◽  
System A ◽  
In Series ◽  
Series Configuration ◽  
Ci Engine

The article discusses the possibility of determining the environmental indicators for vehicles of different categories in relation to CO2 emissions. These are called toxicity indicators because they concern the compounds: CO, THC and NOx. Three Euro V compliant vehicles with different propulsion systems types were used for the study: a 0.9 dm3 urban passenger car with a SI engine and a start-stop system, a 2.5 dm3 off-road vehicle with a CI engine, and a city bus with a hybrid drive system in series configuration and a CI engine with a displacement of 6.7 dm3. Measurements were made in actual operating conditions in the Poznan agglomeration using a portable emissions measurement system (PEMS). The paper presents the characteristics of the operating time shares of vehicles and propulsion systems as well as CO2 emissions depending on the engine load and crankshaft rotational speed for individual vehicles. The determined toxicity indicators allowed to indicate their usefulness, to make comparisons between tested vehicles, and to identify directions for further work on the application and interpretation of these indicators.

scholarly journals Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1566 ◽  
Author(s):  
S.D. Martinez-Boggio ◽  
S.S. Merola ◽  
P. Teixeira Lacava ◽  
A. Irimescu ◽  
P.L. Curto-Risso
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Process ◽  
Visible Spectrum ◽  
Propagation Speed ◽  
Fuel Mixture ◽  
Operating Conditions ◽  
Inert Gases ◽  
Pollutant Emissions ◽  
Si Engine ◽  
Lean Burn

To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible.

Investigation of a Novel Fuel Injection Technology Aimed to Reduce Cold-Start Emissions in SI Engines

2002 ◽  
Author(s):  
Brian T. Reese ◽  
Yann G. Guezennec ◽  
Miodrag Oljaca
Keyword(s):  
Fuel Injection ◽  
Cold Start ◽  
Operating Conditions ◽  
The Novel ◽  
Fuel Injector ◽  
Si Engine ◽  
Fuel Droplets ◽  
Si Engines ◽  
Atomization Characteristics ◽  
Injection Technology

A novel fuel atomization device (Nanomiser™) was evaluated under laboratory conditions with respect to its ability to reduce SI engine cold-start hydrocarbon emissions. First, comparisons between the level of atomization using the conventional, pintle-type fuel injector and the novel atomizer were carried out using flow visualization in a spray chamber and particle size distribution. The novel atomizer is capable of producing sub-micron fuel droplets, which form an ultra-fine mist with outstanding non-wetting characteristics. To capitalize on these atomization characteristics, this device was compared to a conventional fuel injector in a small, two-cylinder, SI engine under a number of operating conditions. Results show a slightly enhanced combustion quality and lean limit under warm operating conditions and a dramatic reduction in unburned HC emission under cold operating conditions, with cold emissions with the Nanomiser™ matching those with a conventional injector under fully warm conditions.

Air-Fuel Ratio Control of Spark Ignition Engines With TWC Using LPV Techniques

2009 ◽  
Author(s):  
Rohit A. Zope ◽  
Javad Mohammadpour ◽  
Karolos M. Grigoriadis ◽  
Matthew Franchek
Keyword(s):  
Design Method ◽  
Spark Ignition ◽  
Operating Conditions ◽  
System Stability ◽  
Linear Matrix ◽  
Pi Control ◽  
Spark Ignition Engines ◽  
Si Engine ◽  
Precise Control ◽  
Fuel Ratio

Precise control of the air-fuel ratio in a spark ignition (SI) engine is important to minimize emissions. The emission reduction strongly depends on the performance of the air-fuel ratio controller for the SI engine in conjunction with the Three Way Catalytic (TWC) converter. The TWC converter acts as a buffer to any variations occurring in the air-fuel ratio. It stores oxygen during a lean operation and releases the stored oxygen during a rich transient phase. The stored oxygen must be maintained close to the current storage capacity to yield maximum benefits from the TWC converter. Traditionally this is achieved using a simple PI control or a gain-scheduled PI control to address the variability in the operating conditions of the engine. This, however, does not guarantee closed-loop system stability and/or performance. In this work a model-based linear parameter varying (LPV) approach is used to design an H∞ controller. The design goal is to minimize the effect of disturbances on the air-fuel ratio and hence the relative storage level of oxygen in the TWC, over a defined operating range for the SI engine. The design method formulated in terms of Linear Matrix Inequalities (LMIs) leads to a convex optimization problem which can be efficiently solved using existing interior-point optimization algorithms. Simulations performed validate the proposed control design methodology.

Modeling of Variable Intake Valve Timing in SI Engine

2006 ◽  
Author(s):  
S. Ahmad Ghazi Mir Saied ◽  
S. Ali Jazayeri ◽  
Amir H. Shamekhi
Keyword(s):  
Internal Combustion Engines ◽  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Major Influence ◽  
Combustion Engines ◽  
Intake Valve ◽  
Si Engine ◽  
Operating Condition ◽  
Valve Motion ◽  
Engine Map

In internal combustion engines valve events and timings are among the most important parameters which have a major influence on the engine’s operation and volumetric efficiency. By using camless valvetrain strategy, improvement in fuel economy as well as an increase in entering air charge is found throughout the engine map with the largest benefits arising from low speed operating conditions. The system offers a continuously variable and independent control of virtually all parameters of valve motion. This permits optimization of valve events for each operating condition without any compromise. In this paper we describe a phenomenological model for an unthrottled operation of a camless intake process of spark-ignited (SI) engine. Initially the cylinder breathing dynamics is modeled and results are validated with experimental data of a conventional engine with cam-driven valve profile during unthrottled operation. Then we determine the most optimized intake valve profile in order to have the most volumetric efficiency and proper operation for each operating condition based on the existing model and using numerical techniques.

Measurement of Exhaust Gas Temperatures: Theoretical and Experimental Analysis

2002 ◽  
Author(s):  
Nicolo` Cavina
Keyword(s):  
Experimental Analysis ◽  
Measurement Errors ◽  
Control Strategies ◽  
Catalytic Converter ◽  
Model Identification ◽  
Operating Conditions ◽  
Exhaust Gas ◽  
Exhaust Manifold ◽  
Si Engine ◽  
Polluting Emissions

The optimal management of the three-way catalytic converter is today widely recognized as one of the means to further reduce Spark Ignition (SI) engine polluting emissions, and therefore to respect future emission regulations. Its conversion efficiency is strictly dependent on the operating temperature, and most engine control strategies are today either based on mathematical models that determine such temperature as a function of the engine operating conditions, or on its direct measurement. It is therefore useful to investigate the errors that could arise when measuring exhaust gas temperatures, either during model identification tests or on board the vehicle. The paper presents a theoretical and experimental analysis on the phenomena that could lead to relevant measurement errors in such applications. A physical model of the heat transfer phenomena that take place in the exhaust manifold has been developed to estimate both the exhaust gas temperatures and the error that would arise while measuring them with typical sensors such as thermocouples. The exhaust manifold of a 1.2 liter SI engine was equipped with different types of sensors for the model identification and validation phases.

Supercharging of SI Engines Using a New Kind of Screw-Type Supercharger

2001 ◽  
Author(s):  
K. von Rueden ◽  
H. Pucher ◽  
J. Nickel
Keyword(s):  
Slide Valve ◽  
Operating Conditions ◽  
Load Control ◽  
Transient Operation ◽  
Si Engine ◽  
Si Engines ◽  
New Type ◽  
Simulation Results ◽  
Stroke Cycle ◽  
Engine Power

Abstract In result of the permanent endeavor to reduce fuel consumption of vehicle engines, nowadays the implementation of downsizing concepts is being enforced. Thereby the desired nominal engine power can be produced by an engine with lower displacement operating with correspondingly higher charging pressure. Mechanical supercharging as well as turbocharging can be considered as a suitable supercharging method. This paper reports on experimental and simulation results regarding the stationary and transient operation of a four-stroke cycle SI passenger car engine supercharged by a new type of screw-type supercharger. In this manner the load control of the SI engine is performed by a supercharger internal slide valve system. Thus not only the throttling losses will be reduced noticeably, but also expansion work can be regained by this supercharger under certain operating conditions. The results obtained will be compared with those of the turbocharged reference engine.

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