Taib Iskandar Mohamad

The Combustion and Performance of a Converted Direct Injection Compressed Natural Gas Engine using Spark Plug Fuel Injector

Compressed natural gas (CNG) has been widely used as alternatives to gasoline and diesel in automotive engines. It is a very promising alternative fuel due to many reasons including adaptability to those engines, low in cost, and low emission levels. Unfortunately, when converting to CNG, engines usually suffer from reduced power and limited engine speed. These are due to volumetric loss and slower flame speed. Direct injection (DI) can mitigate these problems by injecting CNG after the intake valve closes, thus increasing volumetric efficiency. In addition, the high pressure gas jet can enhance the turbulence in the cylinder which is beneficial to the mixing and burning. However, conversion to direct fuel injection (DFI) requires a costly modification to the cylinder head to accommodate the direct injector and also can involve piston crown adjustment. This paper discusses a new alternative to converting to DFI using a device called Spark Plug Fuel Injector (SPFI). It is a combination of a fuel injector and a spark plug which fits into the engine block through the existing spark plug hole. With SPFI, conversion to DFI is simple, cheap and requires no modification to the original structure of the engine, except minor calibration to the ECU. The SPFI was installed on a 0.5 liter single cylinder engine and run at 1100 rpm, WOT and stoichiometric air-fuel ratio. Results showed that engine running with SPFI gained the advantage of significant increased volumetric efficiency, faster burning rate, higher output power and improved fuel conversion efficiency compared to port injection operation in the expense of reduced effective compression ratio.

Experimental Investigation of a Gasoline-to-LPG Converted Engine Performance at Various Injection and Cylinder Pressures with Respect to Propane Spray Structures

Power reduction when converting a gasoline engine to propane can be mitigated by designing an injection system so the heat required for evaporation of the propane is drawn from the intake air. Air is cooled and densified, resulting in volumetric efficiency increase. LPG sprays were imaged using Mie and LIF imaging techniques from a port fuel injector, and from long and short connecting pipes. Images were taken in an optically-accessed pressure chamber at atmospheric pressure and fuel pressures of 1.5 MPa. Images of the pipe-coupled injection spray show significant evaporation in the pipe, whose amount depend on the length and diameter of the pipe. The duration of the LPG pulse at the manifold end is, for 300mm pipes, five times the original duration at the injector, and even greater for 600mm pipes. The narrow sprays and the amount of evaporation that occurs before the fuel enters the manifold explains the differences in engine torque and in-cylinder mixture temperature with the different systems.

A Study on Alternative Fuel Blending for Homogeneous Charge Compression Ignition (HCCI) Engine Using Palm Oil Methyl Ester and RON 97

This paper presents work conducted at the Universiti Kebangsaan Malaysia to support the HCCI Engine Program. The objective of this paper is to develop an engine that employs Homogeneous Charge Compression Ignition (HCCI) combustion and features using Palm Oil Methyl ester as fuel. A Novel of palm oil product usage for HCCI engine fuel was investigated. Different percentage of blend of Palm Oil Methyl Ester and RON 97 was tested using Digital Boom Calorimeter. An experiment based on 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% percentage blending between Palm Oil Methyl Ester and RON 97 produced results with an average of 39 MJ/g. Result shows that a high percentage blending of methyl ester with Ron 97 will increase the calorific value of fuel and this result also shows that a low pressure needed to ignite combustion in combustion chamber because of the high calorific value.

The impact on quality of students through participation in international challenge project - a case study on UKM's students

A survey was conducted to find the impact of quality of students and the experience gained through international challenges outdoor project activities which involved the students of the UKM. The survey was done on the students that participated in the Shell Eco Marathon which was first organized in Malaysia and in Asia region. The objective is to find out whether the students have acquired creativity, self confidence, team work, good management and good communication through project and how the students work in team in achieving the goals of the project. This brief analysis of the survey has shown that the response of the students on quality of good management, good communication and teamwork. There is some indication that project outdoor sports activities have create effective way to poster good management and communication among the team. However, on creativity and innovative thinking, the students have not acquired full creativity and innovative idea on transferring the academic knowledge applied into the project. The hard working effort has created integration among some races Malays and Chinese but the participation of Indian need to be improved. Various qualities, such as cooperation, the self confidence, yearning to be the champion and good leadership were discovered. The hard working effort and high commitment has been shown by the students to work together and having good leadership, good management and good communication. The creativity of the group is still need improvement. This survey has also shown that the project generates healthy understanding amongst students, for integration and exchanges of views for environmental conservation and future sustainable of human life in this region as well as in the whole world. The result of the survey clearly support the positive thinking of the students to demonstrate the good management and good communication amongst the group member and that what takes them to be successful in real life.

Improvement of Engine Performance Using an Adaptive Valve Lift and Timing (AVLT) Mechanism at High Engine Speeds

This paper explains about an improvement of high end performance using an adaptive valve lift and timing mechanism (AVLT). This system is developed with an aim to produce a more powerful engine through a variable valve timing technique. The preliminary design of this system adjusts the valve lift via control lever positioned by the rotation of an electric motor and has the potential to be actuated by a hydraulic cylinder that utilises engine fluids pressure difference with respect to the engine speed which made the valve lifts higher in higher engine speed and loads. The mechanism actuation is determined by a feedback signal of the engine electronic control unit that interacted in relation with the present engine speed and load. Therefore, a continuously dynamic valve lift profile with respect to the engine speed can be achieved thus varies the output performance of an engine. As a result of applying the AVLT on a simulated engine model with the actual parameters, the power and torque were increased in high engine speed (above 4000 rpm). The AVLT is able to increase the default valve lift by up to 35.96%. In high end speed of 7000 rpm, maximum lift of AVLT improved engine power by 4.26%, brake torque by 4.25% and reduced the brake specific fuel consumption by 1.14%. Maximum lift of AVLT increased the engine peak power at 6000 rpm by 2.38%. The product of this research will be useful to optimise the height of the valve lift during operation thus improves the engine performance, fuel economy and emission levels of spark ignition engine.

Smoke Simulation in an Underground Train Station Using Computational Fluid Dynamic

The design of the ventilation and fire safety systems for the Johor Bahru Sentral, a semi-underground train station, part of the Integrated Custom, Immigration and Quarantine Complex (ICIQ) is based on normal Malaysian Standards (MS), British Standards and the local fire department’s requirements. However, the large and complex space in the underground station coupled with scheduled diesel-powered locomotives which frequent the station by stopping or passing require detailed simulations. Both ventilation and the fire safety systems employ Computational Fluid Dynamic (CFD) methods to provide realistic balance against the typical calculations based on spread sheets and certain design software. This study compares smoke simulations results performed by the mechanical and fire consultants with the simulations carried out through this project. An assumption of a locomotive catches fire near the main platform is made. The burning locomotive is the source of the smoke while the occupants on platforms and waiting areas are the subjects to escape safely. The process of the simulation includes modelling and meshing processes on the structure of the railway station imported from Inventor CAD Autodesk software drawing. The CFD simulations are performed using Star-CCM+. The smokes flow around the building with buoyancy forces and extracted via exhaust fans. Through these simulations, we found that when a locomotive catches fire, the passengers could evacuate the building safely before the fire department machinery arrives. Furthermore, we notice that the ventilation fans activation based on detection of hazardous gases may not be efficient way to remove the latter. A schedule clean-up sync with train arrivals effectively removes toxic gas.

Evaluation of Noise and Air Flow on a Motorized Adaptive Valve Lift and Timing Engine

This paper explains about the evaluation of intake air flow, volumetric efficiency and noise of a motor-driven engine that used an adaptive valve lift and timing mechanism (AVLT) on one intake valve. This system is developed with an aim to produce a more powerful engine through variable valve timing and lift technique. The system made the valve lifts higher without increasing the valve lift duration. Therefore, a dynamic valve lift profile with respect to the engine speed can be achieved thus varies the input and output of an engine. As a result of applying the AVLT on a motor-driven engine, the engine noise, emission noise and the mass air flow entering the engine cylinder was increased. When AVLT is employed to a maximum lift, the mass air flow of default intake valve lift was improved within a range from 8% to 46.64% in 500 rpm to 2000 rpm speed range. Maximum lift produced engine noise within a range of 2.57% to 18.13% higher than the default lift throughout all speed. Also, maximum lift produced emission noise within a range of 2.47% to 19.19% higher than the default lift throughout all speed. The product of this research will be useful to optimise the height and timing of the valve lift and the AVLT mountings on the engine head during operation thus improves the engine performance, fuel economy, emission levels and reduced noise of a modified engine.

Combustion Characteristics of Compressed Natural Gas in a Direct Microchannel-Injection Engine under Various Operating Conditions

The combustion characteristics of compressed natural gas (CNG) in a direct microchannel-injection engine under various operating conditions were investigated. In this study, a novel idea for direct CNG microchannel injection was realized with spark plug fuel injector (SPFI). It is a device developed to convert engine to CNG direct injection (DI) operation with minimal cost and technical simplicity. It was installed and tested on a Ricardo E6 single cylinder engine with compression ratio of 10.5:1 without modification on the original engine structure. The engine test was carried out under various operation conditions at 1100 rpm. Burning rates of CNG were measured using normalized combustion pressure method by which the normalized pressure rise due to combustion is equivalent to the mass fraction burned (MFB) at the specific crank angle. The results showed that the MFB of CNG direct injection is substantially faster but initially slower than the ones of port injection. The optimal fuel injection and ignition timings are 190 °CA ATDC and 25 °CA BTDC respectively. The optimal injection pressure was 6 MPa. Combustion durations were not changed with different injection pressures but ignition delay was affected. There was no direct correlation between injection pressure and ignition delay which is most probably due to the effect of charge flow difference. Changing mixture stoichiometry affects the magnitude of ignition delay. Combustion duration, on the other hand increases with leaner mixture.