Knock phenomenon analysis on a diesel-CNG dual fuel engine using experimental fuel ratio

Knock avoidance is crucial to establish a proper Diesel-CNG Dual Fuel (DDF) engine. The causes of this phenomenon are still vague due to the lack of knock detection and characterization methods available. This study presents a knock characterization technique using a statistical analysis based on engine block vibration signal. Several experiments were conducted on a 2.5-litre converted DDF engine running at a constant engine speed between 1400 rpm and 3000 rpm with several diesel to CNG fuel ratio. This study found that when the diesel to CNG fuel ratio reached 70:30 at 1800 rpm to 3000 rpm, and 60:40 at 1400 rpm and 1600 rpm, engine knock was detected. A knock index was calculated from the vibration signal using Band-pass, Rectify, Integrate, and Compare (BRIC) method to determine knock intensity for each engine cycle. A three-sigma rule was applied to determine the threshold level of knock occurrence at the tested engine speeds. The knock thresholds at 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm, 2600 rpm, 2800 rpm, and 3000 rpm were found to have a knock index of 3.72, 3.49, 3.21, 2.71, 2.27, 1.80, 2.02, 1.80, and 1.73 respectively. Using a 5% knock cycle occurrence within the third and sixth standard deviation as a deciding criteria, a knock quality level was categorised as a vague, light, medium, and heavy knock. The analysed result shows that a severe knock occurred due to a sudden transition between a low and high knock intensity in a consecutive engine cycle, which yields a non-periodic mechanical shock. The calculated coefficient of variation of the knock index (COVKI) shows that the severe knock occurred when the COVKI is 0.30 and above. It suggests that the knock phenomenon on a DDF engine occurs due to an abrupt heat release rate during the mixing-controlled combustion phase and micro-explosion during the late combustion phase

Development Eco Idle Kit System for Motorcycle

Eco idle system is a system to reduce exhaust emission, fuel consumption and number of engines spend during idling on the road by shutting off the engines automatically. The purpose of this project is to develop the simulation of an eco-idle system and install it on a motorcycle which is the system will turn off the motor after several seconds in idling mode. In this project, there are a few parts that have been used to develop this system kit for motorcycles. The circuit and coding of the system were created in Integrated Development Environment (IDE) software. Data acquisition System (DAQ) was developed, which will lead to the analysis of acceleration and deceleration of motorcycles. In this simulation, the main component is Arduino UNO. In this project, the coding has been added 4 seconds for engine to stop according to driver’s behaviour in real road conditions. After simulating the eco idle kit system, this kit needs to install to motorcycle which is YAMAHA LC135 to analyse data acceleration and deceleration of motorcycles during development of eco-idle kit system. The test methodologies and results for development of eco idle kit system which were tested in different checkpoints. Five different checkpoints were selected to conduct tests of eco idle kit system. Parking lot student UTHM Campus Pagoh served as the site of each checkpoint, which was used to evaluate the eco idle kit system. In conclusion, the simulation of the eco idle system has been successfully run by the connection between required part and coding of the program

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

Research on The Ultra-Low Emission Technology in Internal Combustion Engine

Increasing the efficiency of internal combustion engines is a technologically proven and cost effective approach to dramatically improving the fuel economy of the nation’s fleet of vehicles in the near- to midterm, with the corresponding benefits of reducing our dependence on foreign oil and reducing carbon emissions. This review paper discusses on the research of ultra-low emission technology in internal combustion engine. Efficiency can be increased by improving combustion processes, minimizing engine losses such as friction, reducing the energy penalty of the emission control system and using recovered waste energy in propulsion. Compliance with exhaust emission regulations will be mandated and requires after-treatment technologies integrated with the engine combustion approaches. Fuels under consideration include hydrocarbon-based. Because of their relatively low cost, high performance, and ability to utilize renewable fuels, internal combustion engines, including those in hybrid vehicles, will continue to be critical to our transportation infrastructure for decades