Single-cylinder 125 CC stepped piston engine for mobility and portable power generation applications

Two-stroke engines is far simpler than four-stroke version from its physical perspective. For a given brake output, two-stroke is lighter, easier to work on, and provide higher power-to-weight ratio than the four-stroke, making it suitable for small platform applications. However a conventional two-stroke engine has a reputation for generating smoke and unburned fuel, a situation which does not meet many emissions regulations, now enforced around the world. Thus for many decades two-stroke engines were not favored, giving ways to four-stroke engines to dominate applications, especially for mobile power-generation purposes. In the quest to improve the potential of such an engine, a group of researchers from the Automotive Development Centre (ADC), Universiti Teknologi Malaysia (UTM) has come up with a 125 cc, air-cooled stepped-piston engine to demonstrate the higher power-to-weight ratio feature, apart from overcoming emission reduction. The engine is designed to mitigate the problem of mixture short circuiting, which is the major hindrance to combustion efficiency, and for this to happen they have incorporated a three-port stratification strategy onto the engine. This paper provides the overview related to the earlier work done to infuse the necessary features and highlights some of the performance features of this unique engine design

Investigation of cylinder deactivation strategies for better fuel consumption using 1-D simulation method

In order to meet consumer and legislation requirements, big investments on key technology strategies have been made to ensure fuel consumption is reduced. Recent technologies for gasoline engines are lean combustion technologies (including direct injection and homogenous charged compression ignition), optimizing intake and exhaust valve timing with valve lift and also cylinder deactivation system (CDA) have been practised to improve the engine efficiency. In this study, the purpose is to investigate the engine behaviour when running at different cylinder deactivation (CDA) strategies. One-dimensional engine model software called GT-Power is used to predict the engine performances. There are total of five strategies that have been studied which include normal mode, spark plug off mode, cylinder deactivation mode, intake normal with exhaust off mode, and intake off with exhaust normal mode. Engine performance outputs of each strategy are predicted and compared at BMEP of 3 bars with engine speed of 2500 rpm. Also, the effect of CDA strategies on in-cylinder pressure and pumping loss are performed. The study shows that all of these cylinder deactivation strategies are significantly reduce the pumping loss (PMEP) and fuel consumption, furthermore increasing the thermal efficiency of the engine. The results suggest that the most beneficial strategy for activating CDA is for the case whereby both the intake and exhaust valves are kept closed. This strategy successfully reduced the BSFC. It found that most of these cylinder deactivation strategies improve the engine performance during part load engine condition

Single-cylinder 125 cc stepped piston engine for mobility and portable power generation applications

Two-stroke engines are far simpler than four-stroke engines from a physical perspective. For a given brake output, two-stroke engines are lighter, easier to work on, and provide higher power-to-weight ratio than four-stroke engines, making them suitable for small platform applications. However, conventional two-stroke engines have a reputation for generating smoke and unburned fuel, meaning they may not meet many emissions regulations, now enforced around the world. Thus, for many decades two-stroke engines have not been not favored, giving way to four-stroke engines for dominant applications, especially for mobile power-generation purposes. In the quest to improve the potential of such an engine, a group of researchers from the Automotive Development Centre (ADC), Universiti Teknologi Malaysia (UTM), has developed a 125 cc, air-cooled stepped-piston engine to demonstrate the higher power-to-weight ratio feature, apart from overcoming emission reduction. The engine is designed to mitigate the problem of mixture short circuiting, which is the major hindrance to combustion efficiency. To this end, they have incorporated a three-port stratification strategy into the engine. This paper provides an overview related to the earlier work done to integrate the necessary features and highlights some of the performance features of this unique engine design

Effect of cylinder deactivation strategies on engine performances using one-dimensional simulation technique

In order to meet consumer and legislation requirements, big investments on key technology strategies have been made to ensure fuel consumption is reduced. Recent technologies for gasoline engines are lean combustion technologies (including direct injection and homogenous charged compression ignition), optimizing intake and exhaust valve timing with valve lift and also cylinder deactivation system (CDA) have been practised to improve the engine efficiency. The purpose of this study is to investigate the engine behavior when running at different cylinder deactivation (CDA) strategies. One-dimensional engine model software called GT-Power is used to predict the engine performances. Five strategies were considered namely normal mode, spark plug off mode, cylinder deactivation mode, intake normal with exhaust off mode, and intake off with exhaust normal mode. Engine performance outputs of each strategy are predicted and compared at BMEP of 3 bars with engine speed of 2500 rpm. Also, the effect of CDA strategies on in-cylinder pressure and pumping loss are performed. The study shows that all of these cylinder deactivation strategies are capable of reducing the pumping loss (PMEP) and fuel consumption, thus increasing the thermal efficiency of the engine. The results suggest that the most beneficial strategy for activating CDA is for the case whereby both the intake and exhaust valves are kept closed. This CDA mode capable of increasing brake thermal efficiency up to 22% at entire engine speeds operation. This strategy successfully reduced the BSFC. It was found that most of these cylinder deactivation strategies improve the engine performance during part load engine condition

Investigation into the selection of an appropriate piston head geometry for a spark ignition engine equipped direct-fuel injector

Constructors of gasoline engines are faced with higher and higher requirements as regards to ecological issues and an increase in engine efficiency at a simultaneous decrease in fuel consumption. Satisfaction of these requirements is possible by the recognition of the phenomena occurring inside the engine cylinder, the choice of suitable optimal parameters of the fuel injection process, and the determination of the geometrical shapes of the combustion chamber and the piston head. The aim of the study was to simulate flow in Direct-Injection Fuel engine with different geometrical shapes of piston head. The method of design piston head shapes was referring to existing motorcycle Demak single cylinder 200cc piston size using Solidwork and ANSYS softwarse. The parameter was shallow and deep bowl design on piston head. In term of fuel distribution throughout the combustion chamber, second model that having deeper bowl shows a better fuel distribution than first model as it manages to direct flow the fuel injected towards the location of spark plug. Therefore, second model is chosen as the best model among the two models as it can create a richer mixture around the spark plug

The effect of bio-based additives on engine performance and emissions of petrol and diesel engine

Fuel additives are additives that are added to fuel in small quantities to give improvement in terms of engine performance and emissions. Aftermarket fuel additives can be divided into two, chemical-based and bio-based. In this project, the effect of bio-based fuel additives on engine performance and exhaust emissions of a petrol and diesel engine is studied. The blending ratio is developed based on the instruction given on the bottle of the additives. The ratio of the fuel additives used for Vivo Racing (VR) is between 0.21% and 0.25%, Vivo Flawless (VF) is between 0.10% and 0.14% and Diesel Energy is between 0.14% and 0.18%. Constant throttle test had been done on both petrol and diesel engine. The results show that the fuel additives reduce brake power and brake specific fuel consumption while increasing brake thermal efficiency and reducing exhaust emissions. For brake power, VR0.24 is the best. For brake specific fuel consumption, the best are VR0.23 and VF0.11 for petrol and diesel engine respectively. For brake thermal efficiency, the best are VR0.24 and DE0.17. For HC composition, the lowest are VR0.25 and DE0.17. For CO composition, VR0.22 and DE0.14 are the lowest. As for NOx, the lowest are VR0.25 and DE0.17

Review on resonator and muffler configuration acoustics

Nowadays, resonators are widely used in automobile, industrial applications, aerospace engineering, and some other fields. One of the unique characteristics of resonators which made them highly convenient is their acoustic capability to attenuate noise without having to use any acoustic absorptive material. The device acts by manipulating the sound waves to create mismatch impedance. Recent studies also suggest that the typical bulk size resonator with narrow frequency bandwidth is not the only option anymore, since there are newly designed resonators that are capable of having wide attenuation bandwidth and are smaller in size. Numerical and experimental measures were executed accordingly with the same purpose to obtain efficient noise attenuation results from varying resonators’ and mufflers’ configuration in terms of quantity, types, and geometry. The aim of this review is to summarize recent developments on resonator study and to try highlighting some noteworthy issues that need to be unraveled by future research. Helmholtz resonator, Quarter wave tube, Herschel-Quincke tube and helicoidal resonator are part of the numerous resonator studies that will be covered in this paper

Conceptual design of remotely operated underwater vehicle

Research in the underwater of the sea is a very interesting field. However, due to the difficulties and dangerous condition, human activities under the sea water are limited. Thus, a dedicated tool or device such as a Remotely Operated Underwater Vehicle (ROV) is required in helping human to perform these research activities. This paper presents design and construction of ROV, which differ depending on its applications. Some of the ROV’s classifications include micro, mini, general, light work class, heavy work class and burial ROV. Therefore, it is essential to identify the design concept and the classification of a new proposed ROV for underwater application. Several main sub-modules need to be considered during the development of ROV, which include structured/ frame and fitting, control unit/CPU, monitoring system (camera), buoyancy and propulsion system. Each module needs to be properly designed so that the ROV can work as planned. This paper presents a concept design of the ROV including its specifications, before the main development and fabrication work can be carried out. The proposed ROV is designed so that it can operate with low resistance. In order to visualize this concept, 3D CAD models had been generated. An external flow analysis of the ROV had also been performed

Fuel consumption mathematical models for road vehicle – a review

Since the invention of the automobile, engineers and researchers alike have worked towards improving the automobile in various ways from safety, handling and performance to efficiency and durability. As technology in the IT and computing sector evolves into a very helpful tool for detailed calculations, an advantage and possibility for detailed models is there to assist with very detailed assessment on fuel and energy consumption on today’s vehicles. This review is meant to explore in detail what has been achieved by years of joint research through advanced modelling and the following factors such as emissions software and how these models play an important role in sustainable road transport for the masses. The mathematical models also display varying characteristics where models are created striking a balance between complexity, accuracy, and the number of variables to be included

Investigation of Cylinder Deactivation (CDA) Application on a Naturally Aspirated Engine

Increasing oil prices and emission legislation have forced automotive company to investigate new methods and technologies to reduce the harmful effect produced from the motor vehicle, particularly CO2 (Carbon-Dioxide). A lot of studies and researches have been put into in order to achieve a zero emission vehicle with the usage of electricity rather than fossil fuel, but the challenge to cost and environmental effect makes an IC engine is still being the predominant power plant for automobile in this century. One of the popular techniques among engine manufacturers to have a better engine efficiency is cylinder deactivation. Cylinder deactivation is a promising method to reduce the fuel consumption and emission by forced the engine to operate at higher load. However, the higher combustion pressure and extreme temperature at firing cylinders will result in higher NOx composition. This paper will investigate further the engine performance, fuel economy and emission by using one-dimensional (1-D) simulation tool. A standard 1.6 litre naturally aspirated four in-line cylinders, port fuel injection engine is modelled and correlated to the measured test data. The model is then simulated with cylinder deactivation mode by deactivating the intake and exhaust valves at cylinders no 2 and no 3 as well as fuel injection at various engine speeds at part load conditions to show improvements in fuel consumption, CO2  emissions, pumping losses and effects on CO and NOx emission. This correlated model is then used to investigate the application of EGR in order to reduce the emission level. Also, the effects on in-cylinder combustion as well as pumping losses are presented. The study shows that the application of EGR is very significant for engine with CDA mechanism to ensure the overall engine fuel consumption and emissions are reduce simultaneously