Four-stroke Motorcycle Engine Research Articles

The effect of Titanium Dioxide (TiO2) based metallic catalytic converter on the four-stroke motorcycle engine performance

Many environmentally friendly automotive technologies have been developed to support the blue sky program. Among the several innovations, metallic catalytic converter (MCC) technology used in environmentally friendly motorcycle exhausts system with titanium dioxide (TiO2) is one of the innovations available to reduce the rise in air pollution due to exhaust emissions. In terms of reducing exhaust emissions, this technology certainly does not doubt its ability. But the problem is that not many researchers have examined the effect of the application of these technologies on engine performance. Thus, the high aim of this study is to analyze the effectiveness of the use of TiO2 based MCC on the four-stroke motorcycle engine performance. This type of experimental research uses a Yamaha Vixion motorcycle as an object of research. Engine performance testing is performed based on SAE J1349, namely Engine Power Test Code-Spark Ignition and Compression Ignition-Net Power Rating. The equipment used in this study is the inertia of the chassis dynamometer, digital tachometer, digital thermometer, humidity meter, and blower. The independent variables in this study are the standard muffler and modified muffler with TiO2 based MCC. The control variables are engine speed, engine oil temperature, ambient air temperature and humidity, and Pertamax fuel, while the dependent variable is engine performance (torque, power, and fuel consumption). Data analysis techniques using quantitative descriptive methods. This study found that the use of environmentally friendly motorcycle mufflers with TiO2 based MCC technology could increase the torque of the Yamaha Vixion motorcycles. In line with these results, vehicle power also increases, and fuel consumption is relatively economical if the TiO2-based MCC is compared to standard exhaust.

Application of Biogasoline in a Four-stroke Motorcycle Engine

The problems facing the world, in relation to the increasing consumption of petroleum and its limited sources, as well as pollution by fuel-related gases, such as CO, have sparked research on the application of biogasoline as an environmentally friendly alternative fuel. Our research aimed to determine engine performance through mixtures of biogasoline and gasoline to measure torque, power, and fuel consumption rate, and to determine the effect of the mixture on the level of air pollution. The biogasoline used was previously prepared from cooking oil through a Cr-zeolite-catalyzed process. The testing methods on the fuel mixture as a working substance included engine performance and exhaust emission tests, applied to four-stroke engines with mixtures with gasoline and biogasoline ratios of 95:5, 90:10, and 85:15. The engine performance test results showed that the highest values of torque, power, and average effective pressure were of the fuel with a composition of 85:15. CO and HC, the two emitted gases with high toxicities, based on the air quality standard, should not be more than 5.5% by volume and 2400 ppm, respectively. In this research, the findings indicated that both substances, not exceeding 3.0% by volume and not more than 200 ppm, respectively, are safe and environmentally friendly.

Preliminary study on effect of oil additives in engine lubricant on four-stroke motorcycle engine

This research focused on effect of commercial oil additive (COA) with engine lubricants of four-stroke motorcycle engine with 110 cc of cylinder. The mineral engine lubricant (MEL) and semi-synthetic engine lubricant (SSEL) have been applied to observe the effect of COA in volume ratio of 1:0.06. The COA was mixture physically with engine lubricants. As a preliminary observation, the mileage was 0, 200 and 300 kilometers. The basic monitoring of lubricant such as, viscosity, flash point, antiwear, oxidation number, total base number and water content, were distinguished between MEL and SSEL in the presence of COA. Blended between MEL and COA has increased the viscosity about 11.11 % from 300 km of mileage, while SSEL and COA only increased 1.25 % of viscosity. The water content analysis revealed that for 300 km of mileage has decreased about 7.72 % found in mixture of SSEL and COA form 300 km of mileage. The results of this study indicated that the role of COA can be applied as an external additive for maintenance purpose of four-stroke motorcycle engine

Unique Needs of Motorcycle and Scooter Lubricants and Proposed Solutions for More Effective Performance Evaluation

<div class="section abstract"><div class="htmlview paragraph">The operating conditions of a typical motorcycle are considerably different than those of a typical passenger car and thus require an oil capable of handling the unique demands. One primary difference, wet clutch lubrication, is already addressed by the current JASO four-stroke motorcycle engine oil specification (JASO T 903:2011). Another challenge for the oil is gear box lubrication, which may be addressed in part with the addition of a gear protection test in a future revision to the JASO specification. A third major difference between a motorcycle oil and passenger car oil is the more severe conditions an oil is subjected to within a motorcycle engine, due to higher temperatures, engine speeds and power densities.</div><div class="htmlview paragraph">Scooters, utilizing a transmission not lubricated by the crankcase oil, also place higher demands on an engine oil, once again due to higher temperatures, engine speeds and power densities. However, because scooter oils do not need to lubricate a wet clutch or protect gears, scooter oils can provide more fuel economy benefits than motorcycle oils, when properly formulated.</div><div class="htmlview paragraph">First, this study compares the piston deposit performance of motorcycle oils and passenger car oils in the API Sequence III Test and in a fired-engine motorcycle piston deposit evaluation. While the API Sequence III Test is certainly an effective tool for ensuring passenger car motor oil piston deposit performance, the results show that some oils formulated to meet the performance requirements of the Sequence III test do not match the performance of motorcycle-specific oils in a motorcycle piston deposit evaluation.</div><div class="htmlview paragraph">Second, this study compares the performance of different oils in the JASO clutch friction test (SAE#2) and in a fired-engine Scooter Fuel Economy Test. The results indicate that JASO MB performance, as determined by the SAE#2 clutch friction test, is not necessarily a predictor of real fuel economy benefit.</div></div>

Effects of gasoline aromatic content on emissions of volatile organic compounds and aldehydes from a four-stroke motorcycle

A new four-stroke carburettor motorcycle engine without any engine adjustments was used to study the impact of fuel aromatic content on the exhaust emissions of organic air pollutants (volatile organic compounds and carbonyls). Three levels of aromatic content, i.e. 15, 25, and 50% (vol.) aromatics mixed with gasoline were tested. The emissions of aromatic fuel were compared with those of commercial unleaded gasoline. The results indicated that the A15 (15 vol% aromatics in gasoline) fuel exhibited the greatest total organic emission improvement among these three aromatic fuels as compared with commercial gasoline, reaching 59%. The highest emission factors of alkanes, alkenes, and carbonyl groups appeared in the reference fuel (RF) among all of the test fuels. A15 showed the highest emission reduction in alkanes (73%), aromatics (36%), and carbonyls (28%), as compared to those of the RF. The highest emission reduction of alkenes was observed when using A25 as fuel. A reduction in fuel aromatic content from 50 to 25 and 15 vol% in gasoline decreased benzene and toluene emissions, but increased the aldehyde emissions. In general, the results showed that the highest emission reductions for the most of measured organic pollutants appeared when using A15 as the fuel.

Optimization of suitable ethanol blend ratio for motorcycle engine using response surface method

In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NOX) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92–4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust pollutant emissions of CO (-29 %) and NOX (-12 %) when compared to pure gasoline fuel. This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.

Combustion Characteristics of HCCI in Motorcycle Engine

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system for internal combustion engines that reduces fuel consumption and exhaust emissions. This work studied a 150 cc air-cooled, four-stroke motorcycle engine employing HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. Kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and exhaust gas recirculation (EGR) rates. Combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for conducting a stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from cylinder pressure. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission of CO. However, EGR is better than λ for decreasing the peak pressure and MRPR without deteriorating the engine output. Advancing the timing of peak pressure causes high peak pressure, and hence increases MRPR. The timing of peak pressure around 10–15 degree of crank angle after top dead center indicates a good appearance for low MRPR.

Effects of sulfur and aromatic contents in gasoline on motorcycle emissions

By investigating the effect of sulfur and aromatic contents in gasoline on the criteria pollutant emissions [CO, total hydrocarbons (THCs), and NO x] and on air toxics in the exhaust from a non-catalyst four-stroke motorcycle engine, inferences can be made concerning the effect of fuel composition on motorcycle emissions. The fuels were blended with different contents of sulfur (40 and 150 ppmw) and aromatics (20 and 30 vol%). The data indicate that the sulfur content does not correlate with the emissions of the criteria pollutants from the catalyst free engine. Instead, lowering aromatic content in gasoline reduced the THC emission by over 30%, especially in the cruising test. The NO x emission, however, showed an inverse correlation with the aromatic content in gasoline. While a reduction of aromatic content in gasoline may decrease emissions of benzene and toluene, it will increase the emission of aldehyde. Since the percentage changes of emission factor of THC and air toxics in the motorcycle were larger than those in passenger cars, the benefit of emission reduction due to fuel composition changes in motorcycles may have significant impacts in health risk analysis.

Numerical and Experimental Analysis of the Intake Flow in a High Performance Four-Stroke Motorcycle Engine: Influence of the Two-Equation Turbulence Models

An experimental and numerical analysis of the intake system of a production high performance four-stroke motorcycle engine was carried out. The aim of the work was to characterize the fluid dynamic behavior of the engine during the intake phase and to evaluate the capability of the most commonly used two-equation turbulence models to reproduce the in-cylinder flow field for a very complex engine head. Pressure and mass flow rates were measured on a steady-flow rig. Furthermore, velocity measurements were obtained within the combustion chamber using laser Doppler anemometry (LDA). The experimental data were compared to the numerical results using four two-equation turbulence models (standard k-ε, realizable k-ε, Wilcox k-ω, and SST k-ω models). All the investigated turbulence models well predicted the global performances of the intake system and the mean flow structure inside the cylinder. Some differences between measurements and computations were found close to the cylinder head while an improving agreement was evident moving away from the engine head. Furthermore, the Wilcox k-ω model permitted the flow field inside the combustion chamber of the engine to be reproduced and the overall angular momentum of the flux with respect to the cylinder axis to be quantified more properly.

Influence of Valve Lift and Throttle Angle on Intake Flow in a High-Performance Four-Stroke Motorcycle Engine

Abstract A high-performance four-stroke motorcycle engine was analyzed at a steady flow rig. The aim of the work was to characterize the fluid dynamic behavior of the engine head during the intake phase. To this purpose a twofold approach was adopted: the dimensionless flow coefficient was used to evaluate the global breathability of the intake system, while the laser doppler anemometry (LDA) technique was employed to define the flow structure within the combustion chamber. The analysis gave evidence of two contrarotating vortices with axes parallel to the cylinder axis and showed variations in the flow structure when moving away from the engine head. Furthermore, the study highlighted the great influence of the throttle angle on the head fluid dynamic efficiency and how this influence changes with the valve lift. Experimental data were correlated by a single curve adopting a new dimensionless plot. Moreover, LDA measurements were used to evaluate the angular momentum of the flux and an equivalent swirl coefficient, and to correlate them to a previous global swirl characterization carried out on the same engine head using an impulse swirl meter.

Energy requirement assessment on an electrically heated catalyst with heat-storing material of a small four-stroke engine during cold start

An electrically heated catalyst (EHC) with heat-storing material of a four-stroke motorcycle engine operating from cold-start conditions was studied to investigate the effect of input energy on the conversion characteristics of the catalyst from cold start. The parameters investigated were the length of the heat-storing material, the heating temperature, the CO setting level, and the heating position. The heating temperatures were 100, 140, 180, and 220 °C and the CO setting levels were 1.3 and 1.8 per cent. The heating positions were at the inlet and mid-section of the catalyst. The heat-storing material was made of stainless steel and was 15 mm wide and 0.3 mm thick. The two lengths tested were 30 and 60 cm. The experimental results showed that good conversion efficiency was attained, even with a low heating energy, using the shorter heat-storing material coupled with a high CO setting. In contrast, good conversion efficiency was not attained with a low heating energy using the longer heat-storing material. Furthermore, heating at the inlet of the catalyst resulted in better CO conversion efficiency with the combination of shorter heat-storing material and higher CO setting. A good CO conversion was also obtained when heating at the mid-section of the catalyst with the combination of longer heat-storing material and higher CO setting. Analysis of the CO converted mass per unit total input energy showed that a peak value generally occurred at a heating temperature of either 140 or 180 °C.

Three-dimensional transient numerical simulation for gas exchange process in a four-stroke motorcycle engine

Three-dimensional transient numerical simulation for gas exchange process in a four-stroke motorcycle engine

Influence of ethanol–gasoline blended fuel on emission characteristics from a four-stroke motorcycle engine

Emission characteristics from a four-stroke motorcycle engine using 10% (v/v) ethanol–gasoline blended fuel (E10) were investigated at different driving modes on the chassis dynamometers. The results indicate that CO and HC emissions in the engine exhaust are lower with the operation of E10 as compared to the use of unleaded gasoline, whereas the effect of ethanol on NO X emission is not significant. Furthermore, species of both unburned hydrocarbons and their ramifications were analyzed by the combination of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). This analysis shows that aromatic compounds (benzene, toluene, xylene isomers ( o-xylene, m-xylene and p-xylene), ethyltoluene isomers ( o-ethyltoluene, m-ethyltoluene and p-ethyltoluene) and trimethylbenzene isomers (1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene)) and fatty group ones (ethylene, methane, acetaldehyde, ethanol, butene, pentane and hexane) are major compounds in motorcycle engine exhaust. It is found that the E10-fueled motorcycle engine produces more ethylene, acetaldehyde and ethanol emissions than unleaded gasoline engine does. The no significant reduction of aromatics is observed in the case of ethanol–gasoline blended fuel. The ethanol–gasoline blended fuel can somewhat improve emissions of the rest species.

Effect of input energy on the emission of a motorcycle engine with an electrically heated catalyst in cold-start conditions

Experimental investigation on the cold-start condition of an electrically heated catalyst of a four-stroke motorcycle engine was carried out at idle operation. The effects of input energy from heaters and unburnt gas oxidation on the exhaust temperature and the exhaust emission were investigated. Apart from heating temperature and the CO setting level, the other studied parameters included the heating position and input energy. The heating temperatures included 100, 140 and 180 °C and the CO levels were set as 1.0%, 1.3%, 1.8% and 2.3%. Six different heating positions were adopted. The experimental results showed that at high CO setting levels, less heating energy was required from the heaters to induce self-initiated reaction of the catalyst. It was also observed that a high total input energy led to a high CO conversion efficiency. Heating at the inlet of the catalyst has also the same effect. When a high heating temperature was coupled with a high CO setting level, self-initiated reaction of the catalyst was easily achieved.

Effects of heating energy and heating position on the conversion characteristics of the catalyst of a four-stroke motorcycle engine in cold start conditions

Abstract The effects of heating energy and heating position on the conversion efficiency of an electrically heated catalyst of a four stroke motorcycle engine under cold start conditions were investigated in this study. In general, during cold start, the operating temperatures of a four stroke motorcycle engine and its catalyst would not be optimized. It was found in this paper that by applying heat to the catalyst however, the reaction of the catalyst could be promoted, which, consequently, improved the conversion efficiency. The experimented parameters were heating energy, heating position, heating temperature and the carbon monoxide (CO) setting level. The heating temperatures included 100, 140 and 180 °C, while three different heating powers and six different heating positions were used. The CO levels were set as 1.0%, 1.8% and 2.3%. The best CO conversion efficiency was obtained by applying heating at the inlet of the catalyst. It was revealed that a high heating power induced a high temperature rising rate and, consequently, a high CO conversion efficiency. In terms of energy economy efficiency, however, heating at the mid-section of the catalyst gave the best results and through a relatively low heating power.

Reaction of the electrically-heated catalyst of a four-stroke motorcycle engine under cold-start conditions with additional enrichment of the intake mixture

By using additional fuel enrichment, the influence of an electrical heater and the oxidation of unburnt exhaust gases on the reaction of an electrically-heated catalyst under cold-start condition of a four-stroke motorcycle engine was investigated. The effects of different cold-start enriching times, heating temperatures, exhaust settings of the CO level and heating positions were studied. The heating temperatures were 60, 80, 100 and 120°C, and the CO levels were 1.0 and 1.8 per cent. The two heating positions were at the inlet and the mid-section of the catalyst. The results showed that additional enrichment of the intake mixture can reduce the heating temperature for self-reaction of the catalyst as well as improve the conversion effciency of the catalyst on the exhaust emissions. High conversion effciency has been achieved for a heating temperature as high as 100°C for the 1.8%CO setting level. It has also been revealed that self-reaction of the catalyst was not possible for a heating temperature of up to 140°C in the case of a 1.0%CO setting level.

Induction Ramming a Motored High-Speed Four-Stroke Reciprocating Engine—Influence of Inlet Port Pressure Waves on Volumetric Efficiency

This paper describes calculation methods and the results obtained from a computer programme written for studying induction ramming in high-speed reciprocating engines. The calculation uses the method of characteristics for analysing the pressure fluctuations in the intake pipe. The calculated airflow figures are compared with results obtained experimentally from a motored air-cooled four-stroke motorcycle engine. Comparison shows a good correspondence between theoretical and experimental results of both the quantity of air flow and the engine speeds at which airflow peaks and troughs occur. The results also clearly illustrate how flow through the valve is affected by pressure variations at the inlet port.