Diesel-cng dual fuel combustion characterization using vibro-acoustic analysis and response surface methodology

Engine conversion process from any diesel vehicle to a diesel-CNG dual fuel system requires additional fuel management. The need for an engine monitoring is vital to ensure the dual fuel operation run smoothly without excessive knocking, which may shorten the life of the engine. Knock and air-fuel ratio (AFR) sensors are commonly used for engine monitoring during fuel management setup. However, the engine output characteristics has been overlooked during the monitoring process. This study is aimed to explore a statistical approach by predicting the relationship between fuel management and engine output characteristics of diesel-CNG dual fuel engine using Response Surface Methodology (RSM). Two inputs which are CNG substitution rate and engine speed were used to predict the engine output characteristics in terms of engine performance, exhaust emissions, combustion pattern and combustion stability. Within the investigation, a statistical method was proposed to analyse the vibro-acoustic signal generated by a knock sensor installed at the outer cylinder wall of the engine. The frequency distribution analysis was applied to interpret the high variability of the vibro-acoustic signal. The results were used as the input for combustion stability in RSM analysis. It also provided useful information with regards to the engine stability. The response surface analysis showed that the CNG substitution rate and its properties significantly influenced the engine output characteristics. This study also describes the methodology to determine the accuracy and the significance of the developed prediction models. The prediction models were validated using confirmation test and showed good predictability within 95% confidence interval. Thus, it is concluded that RSM provide models that predict the engine characteristics with significant accuracy, which contributes to the effectiveness of diesel-CNG dual fuel engine conversion process

Development of Low Cost Radio-Controlled Cars Dynamometer

A dynamometer, often known as a dyno, is a tool used to concurrently measure the rotational speed (rpm) and torque of a moving motor or engine to determine the power output at any given moment. A dynamometer is utilized as part of a testbed for numerous engine development tasks in addition to measuring the power produced by the engine or motor. This study aims to develop a low cost Radio-controlled (RC) cars dynamometer using the concept of small scale chassis dynamometer with size range from 1/20 (12cm-7cm) to 1/10 (35cm-43cm) which can establish the value of RPM, torque and horsepower. In this study, a dynamometer is developed using aluminum profile with size 20mm x 20mm for the chassis with a N35 magnet with size 10mm x 20mm that attached to the gravity roller 50mm x 200mm. The LM393 Hall effect magnetic sensor that connected to Arduino Uno R3 will detect the rotation of the magnet at the roller to calculate RC car RPM, Torque and Horsepower that will be displayed on the Arduino L2C Serial LCD. The result is verified using tachometer to compare the value of the RPM, Torque and Horsepower which provide the percentage error of 0.107%. This dynamometer has potential for STEM activity in the Design and Technology (RBT) subject for student learning in school

CNG-Diesel Dual Fuel Controlling Concept for Common Rail Diesel

Compressed Natural Gas (CNG) is gaining interest as a clean fossil fuel alternative in a diesel dual fuel system. The dual fuel system is proven to provide benefits in terms of fuel consumption and exhaust emission. This article briefly describes a concept of controlling strategy of a CNG-diesel dual fuel system for a common rail diesel engine. A lower diesel common rail pressure was emulated to reduce the diesel fuel quantity, then substitute it with an equivalent CNG fuel quantity. The tuning process is vital to ensure a comparable performance. It requires measurement of lambda values and tuning of both diesel and CNG set values in their respective look-up tables for the whole engine operation. Test results showed that the lambda values are between 1.5 and 3.0, depending on the load demand indicated by the accelerator pedal positions. This concept is relatively easy to be implemented, but it may cause poor combustion and emission quality due to poor diesel fuel atomization at lower injection pressure. However, an optimum performance and emission could be achieved by scrutinizing the diesel fuel reduction and CNG fuel substitution

Energy consumption and emissions of diesel-CNG dual fuel engine at high load operation

Global warming and energy sustainability issues are among the major world concern. Malaysian National Green Technology Policy 2009 and Thailand Power Development Plan 2015-2036 (PDP 2015) were launched to enhance the green and sustainable energy usage. Meanwhile in the transportation sector, National Automotive Policy (NAP) has been implemented and revised to enhance the usage of the green energy, in order to achieve a low carbon emission and energy efficient vehicle. Researchers keep striving to find alternative solutions to power vehicles by cleaner energy efficiently. Compressed Natural Gas (CNG) has lower carbon emission and higher energy density compared to common petroleum fuel. It provides an opportunity to power the vehicle cleanly. Thus, it has been used as an alternative for fueling gasoline engine. However, CNG fuel is difficult to be applied on diesel engine. Unlike gasoline engine, diesel engine does not have spark plug and its fuel is combusted through compression in cylinder. Since CNG has high octane number, it is difficult to self-ignite in diesel engine. Therefore, Diesel-CNG Dual Fuel (DDF) system is applied. The system use CNG as part fuel and certain amount of diesel pilot fuel is injected into the cylinder to ignite the combustion. DDF engine may potentially reduce Carbon Dioxide (CO2) emission. However, high fuel consumption and Nitrogen Oxide (NOX) emission have been observed at high load engine operation due to improper fuel ratio. In this study, four ratios of DDF were tested and compared with 100% diesel: 90D10G, 80D20G, 70D30G, 60D40G. It was found that each of the fuel ratio behaved differently in terms of brake specific energy consumption (BSEC) and exhaust emissions

Energy consumption and emissions of diesel-CNG dual fuel engine at high load operation

Global warming and energy sustainability issues are among the major world concern. Malaysian National Green Technology Policy 2009 and Thailand Power Development Plan 2015-2036 (PDP 2015) were launched to enhance the green and sustainable energy usage. Meanwhile in the transportation sector, National Automotive Policy (NAP) has been implemented and revised to enhance the usage of the green energy, in order to achieve a low carbon emission and energy efficient vehicle. Researchers keep striving to find alternative solutions to power vehicles by cleaner energy efficiently. Compressed Natural Gas (CNG) has lower carbon emission and higher energy density compared to common petroleum fuel. It provides an opportunity to power the vehicle cleanly. Thus, it has been used as an alternative for fueling gasoline engine. However, CNG fuel is difficult to be applied on diesel engine. Unlike gasoline engine, diesel engine does not have spark plug and its fuel is combusted through compression in cylinder. Since CNG has high octane number, it is difficult to self-ignite in diesel engine. Therefore, Diesel-CNG Dual Fuel (DDF) system is applied. The system use CNG as part fuel and certain amount of diesel pilot fuel is injected into the cylinder to ignite the combustion. DDF engine may potentially reduce Carbon Dioxide (CO2) emission. However, high fuel consumption and Nitrogen Oxide (NOX) emission have been observed at high load engine operation due to improper fuel ratio. In this study, four ratios of DDF were tested and compared with 100% diesel: 90D10G, 80D20G, 70D30G, 60D40G. It was found that each of the fuel ratio behaved differently in terms of brake specific energy consumption (BSEC) and exhaust emissions

The Effect of Different Reynolds Number On Solid Sphere Using CFD and Its Verification

Aerodynamic behaviour of an object depends on several factors, namely shape, size and flow conditions. Thus, CFD simulations are an effective engineering tools that allows major contribution to understand the flow conditions around an object. This study aims to analyse the effect of two various shapes of spherical models on aerodynamics behaviour for different Reynolds number between 100,000 ≤ Re ≤ 800,000. Geometry models are generated using SolidWorks 2017 and numerical solution is analysed using ANSYS CFX. The numerical results are later compared with experimental data collected from wind tunnel. At the end of the study, the nature flow around spherical models of different Reynolds number are visualized. It is discovered that the flow behaviour around the spherical model changes as the Reynolds number increases. This finding is parallel with past researchers. These forecasts should assist engineers enhance the application of aerodynamic and hydrodynamic design

The Effect of Different Reynolds Number On Solid Sphere Using CFD and Its Verification

Aerodynamic behaviour of an object depends on several factors, namely shape, size and flow conditions. Thus, CFD simulations are an effective engineering tools that allows major contribution to understand the flow conditions around an object. This study aims to analyse the effect of two various shapes of spherical models on aerodynamics behaviour for different Reynolds number between 100,000 ≤ Re ≤ 800,000. Geometry models are generated using SolidWorks 2017 and numerical solution is analysed using ANSYS CFX. The numerical results are later compared with experimental data collected from wind tunnel. At the end of the study, the nature flow around spherical models of different Reynolds number are visualized. It is discovered that the flow behaviour around the spherical model changes as the Reynolds number increases. This finding is parallel with past researchers. These forecasts should assist engineers enhance the application of aerodynamic and hydrodynamic design

Analysis of user’s comfort on automated vehicle riding simulation using subjective and objective measurements

The naturalistic study investigated the potential influence of personal driving preferences (assertive and defensive driving style) on users; comfort when being driven in an automated vehicle with a defensive driving style. Adopted the Wizard of Oz design, the study involved three phases: pre-, during, and post-driven to measure their comfort, perceived safety, and likeness as well as motion sickness propensity through self-report questionnaire and heart rate variation. After answering a set of questionnaires, participants were exposed to simulated driving in an automated vehicle with a defensive driving style. A statistical analysis produced no statistically significant difference between assertive and defensive participants. This indicates an overall preference, perceived comfort without severe motion sickness propensity to the defensive driving style of the autonomous vehicle, regardless of participants’ personal driving styles

Effects of ride comfort on different non-driving related activities in fully automated driving experience

A fully automated vehicle (AV) is projected to free users from driving activities. However, motion sickness (MS) is expected to be experienced by the users when engaging in Non-Driving Activities (NDRAs) such as reading, and watching a video because they will be exposed to low-frequency movement that contributes to the development of motion sickness. This study analyzed the difference in users’ ride comfort when traveling in an AV in a real-road situation. The Wizard of Oz method was implemented for the participants to experience fully automated driving. The study was divided into three stages: pre-, during, and post-driven, to measure the user’s comfort, safety, likeness, and motion sickness level through self-report questionnaires. Three conditions of NDRA consisting of baseline (doing nothing), reading, and watching a video were tested among the young participants (18 to 28 years old, Mean = 21.4, Standard Deviation = 2.84). Statistical analysis showed a statistically significant difference between the three different NDRAs. Reading imposed the highest experienced MS followed by watching a video and doing nothing. Understanding ride comfort in AV riding is vital in designing an AV that makes the passenger enjoy the ride without any discomfort feeling (motion sickness), especially when engaging in any NDRA

Effects of ride comfort on different non-driving related activities in fully automated driving experience

A fully automated vehicle (AV) is projected to free users from driving activities. However, motion sickness (MS) is expected to be experienced by the users when engaging in Non-Driving Activities (NDRAs) such as reading, and watching a video because they will be exposed to low-frequency movement that contributes to the development of motion sickness. This study analyzed the difference in users’ ride comfort when traveling in an AV in a real-road situation. The Wizard of Oz method was implemented for the participants to experience fully automated driving. The study was divided into three stages: pre-, during, and post-driven, to measure the user’s comfort, safety, likeness, and motion sickness level through self-report questionnaires. Three conditions of NDRA consisting of baseline (doing nothing), reading, and watching a video were tested among the young participants (18 to 28 years old, Mean = 21.4, Standard Deviation = 2.84). Statistical analysis showed a statistically significant difference between the three different NDRAs. Reading imposed the highest experienced MS followed by watching a video and doing nothing. Understanding ride comfort in AV riding is vital in designing an AV that makes the passenger enjoy the ride without any discomfort feeling (motion sickness), especially when engaging in any NDRA