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

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

Improvement of Combustion Process and Exhaust Emissions with Premixed Charge Compression Ignition

Premixed Charge Compression Ignition (PCCI) is a combustion concept that is characterized by low temperature, partially premixed combustion using early injections, large ignition delays and high percentages of Exhaust Gas Recirculation. This review paper discusses the premixed charge compression ignition (PCCI) and the way to reduce the emissions. A promising low-emission combustion concept is used by the premixed charge compression ignition (PCCI). Air and exhaust gas before auto-ignition, the soot and NOx emissions are lower than for conventional diesel combustion by partially mixing the fuel. Fuel lean premixed combustion has potentials to achieve high efficiency and low emissions. The ignitability of lean mixture, flame stability and controlling in this combustion are significant issues to be addressed. The main issues for lean burn intermittent combustion engines are (i) the mixture preparation for lean combustion requires expensive or premium technology and (ii) achieving this combustion over a wide range of load and speed is difficult for a smooth-running engine