scholarly journals Technical and operating problems yielded from setting up the optimum value of geometric compression ratio in piston engines

2016 ◽  
Vol 164 (1) ◽  
pp. 3-14
Author(s):  
Paweł WOŚ ◽  
Artur JAWORSKI ◽  
Hubert KUSZEWSKI ◽  
Kazimierz LEJDA ◽  
Adam USTRZYCKI
Keyword(s):  
Compression Ratio ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Exhaust Emission ◽  
Road Transportation ◽  
Design Structure ◽  
Operational Characteristics ◽  
And Performance ◽  
And Control ◽  
The Impact

The article discusses the problem of choosing the optimal compression ratio value in internal combustion engines at their design phase, according to todays development trends toward high economy and ecology of road transportation and the divers expectations in vehicle use and performance. Because the variable compression ratio technology VCR is not yet developed well enough to be implemented into the mass production of engines in the near future, the choice of compression ratio value is always a serious task for constructors to find a compromise between the functional engine properties, operational characteristics, engine efficiency, the powertrain design complexity, and finally the exhaust emission level. Therefore, the paper examines the impact of the compression ratio on the combustion engine parameters mentioned above and presents some innovative designs, where the settings of the compression ratio value beyond the conventional range is connected with using additional solutions in design structure and control systems, with modifications corresponding to the working process in these engines.

scholarly journals The Impact of Powering an Engine with Fuels from Renewable Energy Sources including its Software Modification on a Drive Unit Performance Parameters

2019 ◽  
Vol 11 (23) ◽  
pp. 6585 ◽  
Author(s):  
Markiewicz ◽  
Muślewski
Keyword(s):  
Renewable Energy ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Renewable Energy Sources ◽  
Internal Combustion ◽  
Energy Sources ◽  
Exhaust Emission ◽  
Combustion Engines ◽  
Performance Parameters ◽  
The Impact

The application of fuels from renewable energy sources for combustion engine powering involves a great demand for this kind of energy while its production infrastructure remains underdeveloped. The use of this kind of fuel is supposed to reduce the emission of greenhouse gases and the depletion of natural resources and to increase the share of renewable energy sources in total energy consumption and thus support sustainable development in Europe. This study presents the results of research on selected performance parameters of transport by internal combustion engines including: power, torque, the emission of sound generated by the engine, the content of exhaust components (oxygen O2, carbon monoxide CO, carbon dioxide CO2, nitrogen dioxide NO2), and the content of particulate matter (PM) in exhaust emission. Three self-ignition engines were tested. The fuel injection controllers of the tested internal combustion engines were additionally adjusted by increasing the fuel dose and the load of air. The material used in the tests were mixtures of diesel oil and fatty acid methyl esters of different concentration. A statistical analysis was performed based of the results. The purpose of the work was to develop a resulting model for assessing the operation of engines fueled with biofuel and diesel mixtures while changing the vehicle's computer software. A computer simulation algorithm was also developed for the needs of the tests which was used to prognose the state of the test results for variable input parameters.

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.

A comprehensive evaluation of water injection in the diesel engine

2021 ◽  
pp. 146808742110442
Author(s):  
Sebastian Welscher ◽  
Mohammad Hossein Moradi ◽  
Antonino Vacca ◽  
Peter Bloch ◽  
Michael Grill ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engines ◽  
Comprehensive Evaluation ◽  
Combustion Engine ◽  
Water Injection ◽  
Combustion Process ◽  
Internal Combustion ◽  
Exhaust Emission ◽  
Pressure Trace ◽  
High Level

Due to increasing climate awareness and the introduction of much stricter exhaust emission legislation the internal combustion engine technology faces major challenges. Although the development and state of technology of internal combustion engines generally reached a very high level over the last years those need to be improved even more. Combining water injection with a diesel engine, therefore, seems to be the next logical step in developing a highly efficient drive train for future mobility. To investigate these potentials, a comprehensive evaluation of water injection on the diesel engine was carried out. This study covers >560 individual operating points on the test bench. The tests were carried out on a single-cylinder derived from a Euro 6d four-cylinder passenger car with the port water injection. Furthermore, a detailed pressure trace analysis (PTA) was performed to evaluate various aspects regarding combustion, emission, etc. The results show no significant effects of water injection on the combustion process, but great potential for NOx reduction. It has been shown that with the use of water injection at water-to-fuel rates of 25%, 50%, and 100%, NOx reduction without deterioration of soot levels can be achieved in 62%, 40%, and 20% of the experiments, respectively. Furthermore, water injection in combination with EGR offers additional reduction in NOx emissions.

A comparative study of the effect of compression ratio on the efficiency and flame development angle in a Cooperative Fuel Research engine fueled with binary gasoline–alcohol blends

2019 ◽  
pp. 146808741985910 ◽  
Author(s):  
Guillermo Rubio-Gómez ◽  
Lis Corral-Gómez ◽  
David Rodriguez-Rosa ◽  
Fausto A Sánchez-Cruz ◽  
Simón Martínez-Martínez
Keyword(s):  
Comparative Study ◽  
Compression Ratio ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Flame Development ◽  
The Impact

In the last few years, increasing concern about the harmful effects of the use of fossil fuels in internal combustion engines has been observed. In addition, the limited availability of crude oil has driven the interest in alternative fuels, especially biofuels. In the context of spark ignition engines, bioalcohols are of great interest owing to their similarities and blend capacities with gasoline. Methanol and ethanol have been widely used, mainly due to their knocking resistance. Another alcohol of great interest is butanol, thanks to its potential of being produced as biofuel and its heat value closer to gasoline. In this study, a comparative study of gasoline–alcohol blend combustion, with up to 20% volume, with neat gasoline has been carried out. A single-cylinder, variable compression ratio, Cooperative Fuel Research-type spark ignition engine has been employed. The comparison is made in terms of fuel conversion efficiency and flame development angle. Relevant information related to the impact in the combustion process of the use of the three main alcohols used in blends with gasoline has been obtained.

The Impact of Reduced Speech Intelligibility on Reaction Time in a Naval Combat Environment

2017 ◽  
Vol 61 (1) ◽  
pp. 1570-1574 ◽  
Author(s):  
Benjamin Sheffield ◽  
John Ziriax ◽  
M. David Keller ◽  
William Barns ◽  
Douglas Brungart
Keyword(s):  
Hearing Loss ◽  
Speech Intelligibility ◽  
Noise Exposure ◽  
Impaired Hearing ◽  
Perceived Workload ◽  
Series Of Experiments ◽  
And Performance ◽  
And Control ◽  
The Military ◽  
The Impact

Despite attempts to limit noise exposure, noise-induced hearing loss remains prevalent in the military. Both hearing loss and the noise itself can lead to communication issues which could negatively impact operational performance. This study builds upon a series of experiments examining the relationship between reduced speech intelligibility and performance in a naval command and control environment by equipping Navy watch standers with hearing loss simulators that control speech intelligibility in real time as they were engaged in a simulated operational scenario. This effort focused on the effects that a Sailor with impaired hearing might have on unimpaired shipmates and how the mission might specifically be impacted. Results showed that as speech intelligibility decreased for the impaired watch stander perceived workload increased in an unimpaired shipmate and the latency of the crew to respond to incoming missile threats and a direct order to kill an enemy ship increased significantly.

scholarly journals Application of SPC in Short Run and Small Mixed Batch Production: Case of Bakery Equipment Producer

2018 ◽  
Vol 22 (3) ◽  
pp. 55 ◽  
Author(s):  
Darina Juhászová
Keyword(s):  
Control Charts ◽  
Single Case ◽  
Statistical Process ◽  
Pareto Analysis ◽  
Environmental Consequences ◽  
Starting Point ◽  
Short Run ◽  
And Performance ◽  
And Control ◽  
The Impact

<p><strong>Purpose: </strong>The purpose of this paper is to present preliminary research in statistical process control (SPC) of short run and small mixed batches (SR-SMB) at the organization producing bakery equipment.</p><p><strong>Methodology/Approach:</strong> The starting point of the research is a literary survey of possibilities of using SPC for SR-SMB and analysis of the current state of production in a particular organization. Through Pareto analysis, verifying the normality of the data obtained during eleven months, calculation of process capability and performance it was possible to prepare control charts. Finally, the single-case study shows that the proposed control charts are applicable in a small batch and mixed production in the organization producing bakery equipment.</p><p><strong>Findings: </strong>Through SPC implementation in bakery equipment SR-SMB production it is possible to understand the behaviour of the process and to organize better and control the production of expensive precision components.</p><p><strong>Research Limitation/implication:</strong> Limitation of the research is that data have not been reviewed by individual machines and the impact of individual machines and their settings is not displayed separately.</p><strong>Originality/Value of paper:</strong> Using SPC in the bakery equipment industry is far from common practice. The article presents the first part of the research, which is the starting point for more detailed analysis needed to optimize the use of materials, energy and environmental consequences.

scholarly journals Maintenance Performance of Prison Facilities in Southwestern Nigeria

2019 ◽  
Vol 3 (2) ◽  
pp. 26-34
Author(s):  
O. O. Ajayi ◽  
H. Koleoso ◽  
M. Ajayi ◽  
O. Faremi
Keyword(s):  
Sampling Technique ◽  
Performance Criteria ◽  
Southwestern Nigeria ◽  
Prison Staff ◽  
Quality Of Water ◽  
And Performance ◽  
The One ◽  
And Control ◽  
The Impact ◽  
Maintenance Performance

Maintenance performance measurement aims to assess and improve the value created after maintenance efforts, as it determines the impact of maintenance on the performance of a system or facility and its business process. As objects of maintenance, prison facilities ought to provide a safe and decent environment for prison staff and prisoners to work and live in, as well as for all others who interact with the facilities. This study evaluates the satisfaction ratings of maintenance performance on prison facilities in Southwestern, Nigeria. A survey approach was adopted to collect data from the relevant Nigerian prison staff population of 2,187 prison workers, excluding staff in the maintenance unit within a specific period. Stratified sampling technique was used to generate a sample of 1,094, which is representative of the entire population across the prisons. Three hundred and eighty (35%) out of the one thousand and ninety-four copies of the questionnaire were completed and returned. Data collected were analysed using the SPSS package. The study found that prison staff showed satisfaction with the level of cleanliness in the prison environment, quality of water and control of ventilation employing a window, as well as partial satisfaction with the twenty-nine other criterion assessed. Overall, the study indicated partial satisfaction for performance on prison facilities and established a significant agreement among prison staff regarding the perception of the performance of prison facilities. The research, therefore, suggests continuous evaluation of maintained prison facilities to ascertain their condition and performance levels. Keywords: Maintenance Performance Criteria; Prison Facilities; Prison Staff; Satisfaction Ratings

scholarly journals The Relationship between Extent of Internationalization and Firm Performance (Taiwan 1992–2017)

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Shih-Yung Wei ◽  
Li-Wei Lin
Keyword(s):  
Firm Performance ◽  
Operating Performance ◽  
Board Structure ◽  
Tobin’S Q ◽  
Tobin's Q ◽  
Moderating Variables ◽  
Average Operating ◽  
And Performance ◽  
And Control ◽  
The Impact

The purpose of this study was to discuss the impact of the extent of internationalization on firm performance measured for firms with a high Tobin’s Q (firms with good operating performance), a median Tobin’s Q (firms with average operating performance), and a low Tobin’s Q (firms with poor operating performance). In addition to discussion on the impact of internationalization on firm performance, this study also discussed the impact of corporate proprietary assets (using assets, R&D, marketing, and management-related variables as moderating variables) and control variables (scale of company, debt-asset ratio, firm age, board structure, and proportion of pledged shares by directors) on firm performance. The research results showed that there is an S-shaped relationship between extent of internationalization and firm performance. However, further discussion found that there is an S-shaped relationship between extent of internationalization and performance for firms with a high Tobin’s Q but a slight decline in the middle of the S-shaped curve, as well as a general linear negative correlation between extent of internationalization and performance for firms with a median Tobin’s Q and an inverted U-shaped correlation between extent of internationalization and performance for firms with a low Tobin’s Q.

scholarly journals The impact of vehicle dynamic parameters on the exhaust emissions in RDE tests

2018 ◽  
Vol 175 (4) ◽  
pp. 26-34
Author(s):  
Jacek PIELECHA ◽  
Karolina KURTYKA ◽  
Kinga SKOBIEJ
Keyword(s):  
Internal Combustion Engines ◽  
Exhaust Emissions ◽  
Exhaust Emission ◽  
Dynamic Parameters ◽  
Passenger Cars ◽  
The Road ◽  
Positive Acceleration ◽  
Legislative Proposals ◽  
Test Route ◽  
The Impact

The article compares driving test data using the latest legislative proposals applicable to passenger cars with different drives. For this purpose, cars of one type were selected, meeting the same exhaust toxicity standard (Euro 6c) and differing in used internal combustion engines (with spark-ignition, compression-ignition and hybrid drive). Several measurements were performed on the same test route in accordance with the RDE test guidelines, which requires a several of criteria to be met. These criteria include the length of the measuring sections, their overall timeshare and the dynamic characteristics of the drive. A portable emissions measurement system (PEMS) was used to record the engine and vehicle operating parameters and to measure the exhaust emissions during tests. This allowed for the monitoring of parameters such as: load value, engine speed and vehicle velocity. Then the obtained results were analyzed for their compatibility with the RDE procedure requirements. By determining the road emission of individual harmful compounds for all vehicles and the dynamic parameters of drive (relative positive acceleration and product of speed and positive acceleration) in various phases of the road test it was possible to compare them. On this basis, the impact of dynamic conditions of road tests on the obtained results of the road exhaust emission of harmful compounds for passenger cars with various drives was defined.

scholarly journals The Impact of Formative Computer-Based Testing on Learners’ Anxiety and Performance on the American Registry for Diagnostic Medical Sonography Examination

2018 ◽  
Vol 34 (6) ◽  
pp. 425-433
Author(s):  
Michelle Wilson
Keyword(s):  
Treatment Group ◽  
Control Group ◽  
Web Based ◽  
National Board ◽  
Computer Based ◽  
Preparatory Stage ◽  
And Performance ◽  
Dependent Sample ◽  
And Control ◽  
The Impact

The intent of this research was to evaluate the effects of computerized mock examinations on student performances during the preparatory stage for a national board examination. Three measures were used: web-based surveys, student data from the ExamSim software (treatment group), and American Registry for Diagnostic Medical Sonography (ARDMS) examination scores. Three research questions were posed: (1) What are the differences in ARDMS scores between the treatment and control groups? Mean scores showed that the treatment group scored significantly higher than the control group on the ARDMS examination. (2) To what degree did the scores and time invested on the ExamSim software predict performance on the ARDMS examination? A multiple linear regression was conducted, and the result was significant, with time and software scores accounting for 37.6% of the variance in ARDMS scores. (3) How did utilizing a formative computer-based assessment change perceived testing anxiety levels during the test preparatory phase? The result of the dependent sample t test was significant. Self-perceived scores at posttreatment were lower than self-perceived scores at pretreatment.

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