Search

The study has focused on determining the laser plug effects on engine characteristics and the laser plug usage results have compared with spark plug usage. The laser ignition technique is a type of new ignition technique and an important solution that can make combustion systems more efficient. The testing of an engine with a laser plug is the novelty of the study and the tests were carried out with reference to equivalence ratio and plug power ranges. The behaviors of the engine at full load were examined so experimentally for both ignition techniques at hydrogen enriched CNG and iso-octane mixture usage. The tests were carried out for variations of 0.4–2.0 equivalence ratio and 20–120 W plug power. A mixture that 90% iso-octane and 10% HCNG in mass was used at two ignition modes in tests for 3300 rpm maximum engine torque speed. Also, the flame formation and propagation for both ignition techniques were detected via a high-speed camera. The tests have shown the laser ignition leads to more energy consumption in the rich mixture conditions and also, less energy is required in the lean conditions. The laser ignition discharge has extended the engine's lean combustion limits via a small energy input at the tests. The high-speed camera images have shown that the laser ignition reduces the Kernel flame formation and propagation time. The laser ignition technique was produced less NOx than the conventional spark ignition method.

In this study, the high-speed of 2000 rpm and low-speed of 1000 rpm behaviors on the HCCI test engine at full load were examined experimentally by controlling the intake air temperature. The tests were carried out at 0.90 equivalence ratio for hydrogen-enriched kerosene-dimethyl ether mixture. In order to expand the usage of HCCI engines in daily life, their problems encountered at high loads and high speeds need to be solved. The main reason of these problems is the control of the start of combustion since there is no external combustion system in HCCI engines. The experimental results show that the intake air temperature directly affects engine performance and emissions. The intake air temperature control was led to shorter flame development time and better combustion stability. The in-cylinder pressure at 1000 rpm for 373 K is overall 6.82% and 4.07% higher than the 273 K and 298 K. The average heat release rate curve trends at 1000 rpm are overall 45.68% higher than 2000 rpm. The brake specific fuel consumption for 2000 rpm is about 5.29% higher than 1000 rpm. The differences between the two NOx trends are 35.4% maximum and 11.03% minimum for 1000 rpm and 2000 rpm. At high engine speed, the HC formation drops linearly from 488 ppm to 339 ppm with increasing air temperature. Also, the soot formation decreased with a slope of 1.58 times higher than 1000 rpm. Overall, the increase in intake air temperature at the tests positively affected in-cylinder pressure, CO, HC and soot.

A prototype opposed-piston engine was tested with gasoline, ethanol, methyl tert-butyl ether (MTBE) and a gasoline–ethanol blend (E85) at full load. This is the first test of an opposed-piston engi...

In this study, the effects of ignition advance on dual sequential ignition engine characteristics and exhaust gas emissions for hydrogen enriched butane usage and lean mixture were investigated numerically and experimentally. The main purpose of this study is to reveal the effects of h-butane application in a commercial spark ignition gasoline engine. One cylinder of the commercially dual sequential spark ignition engine was modeled in the Star-CD software, taking into account all the components of the combustion chamber (intake-exhaust manifold connections, intake-exhaust valves, cylinder, cylinder head, piston, spark plugs). Angelberger wall approximation, k-e RNG turbulence model and G-equation combustion model were used for analysis. In the dual sequential spark ignition, the difference between the spark plugs was defined as 5° CAD. At the numerical analysis; 10.8:1 compression ratio, 1.3 air-fuel ratio, 2800 rpm engine speed, 0.0010 m the flame radius and 0.0001 m the flame thickness were kept constant. The hydrogen-butane mixture was defined as 4%–96% by mass. In the analysis, the optimal ignition advance was determined by the working conditions. In addition, the effects of changes in ignition advance were examined in detail at lean mixture. For engine operating conditions under investigation, it has been determined that the 50° CAD ignition advance from the top dead center is the optimal ignition advance in terms of engine performance and emission balance. It has also been found that the NOx formation rises up as the ignition advance increases. The BTE values were approximately 12.01% higher than butane experimental results. The experimental BTE values for h-butane were overall 3.01% lower than h-butane numerical results.

This study focuses on determining the effects of gasoline, ethanol, methyl tert-butyl ether (MTBE) and a gasoline–hydrogen mixture (G98H2) on engine performance and hydrocarbon (HC) emission for a ...

Compared to widening usage of CNG in commercial gasoline engines, insufficient but increasing number of studies have appeared in the open literature during last decades, while engine characteristics need to be quantified in exact numbers for each specific fuel and engine. CNG usage in spark-ignition engine offers many advantages such as high specific power outputs, knock resistance, and low CO2 emission. Engine performance and emissions are strong functions of equivalence ratio. This study focuses on determination of the effects of equivalence ratio on engine performance and emissions for a unique commercial engine for three fuels of gasoline, CNG, and gasoline–CNG mixture (90%–10%: G9C1). For this aim, the tests and the three-dimensional in-cylinder combustion computational fluid dynamics analyses were employed in quantification of engine characteristics at wide open throttle position. Equivalence ratios were defined between 0.7 and 1.4. The engine’s maximum torque speed of 2800 r/min was examined. The tested commercial engine is an intelligent dual sequential ignition engine which has unique features such as diagonally positioned two spark-plugs, dual sequential ignition with variable timing and asymmetrical combustion chamber. This gasoline engine was equipped with an independent CNG port-injection system and a specific engine control unit for CNG. In addition, the engine test system has a concomitant dual fuel delivery system that supplies gas fuel into intake airline while liquid gasoline is injected behind the intake valve. Other than testing the engine, the three-dimensional in-cylinder combustion computational fluid dynamics analyses were performed in Star-CD/es-ice software for the three fuels. The CFD model was built by using renormalization group equations, k–ε turbulence model, and G-equation combustion model. Computational fluid dynamics analyses were run for the compression ratio of 10.8:1, equivalence ratio of 1.1, and engine’s maximum torque speed of 2800 r/min. Test results show that brake torque for all fuels increases rapidly from the lean blend to the rich blend. The brake-specific fuel consumption for all fuels decreases from Φ = 0.7 through the stoichiometric region and then slightly increases up to Φ = 1.4. The volumetric efficiencies for three fuels have similar decreasing trend with respect to equivalence ratio. Overall, CNG addition decreases the performance values of torque, brake-specific fuel consumption, volumetric efficiency, brake thermal efficiency, while it decreases emissions of CO2, CO, HC, except NOx. Engine model results show that the maximum in-cylinder pressure is 72 bar at 722 crank angle degree (CAD), 68 bar at 730 CAD, and 60 bar at 735 CAD for gasoline, CNG, and G9C1, respectively. The cumulative heat release for gasoline is 9.09% higher than G9C1, while G9C1 is 15.71% higher than CNG. The CO2 mass fraction for gasoline is about 22.58% lower than G9C1, while it is 40.32% higher than CNG. The maximum mass fraction value of CO is 0.21, 0.17, and 0.08 for gasoline, CNG, and G9C1, respectively. The CO for G9C1 is overall 60.04% lower than CNG and 67.45% lower than gasoline. At maximum point, HC for G9C1 is 31.43% and 71.43% higher than gasoline and CNG, respectively. CNG has the highest level of NOx formation. Maximum NOx mass fractions are 0.0098, 0.0070, and 0.0043 for CNG, G9C1, and gasoline, respectively. After the ignition, the flame development is completed at 1.07, 1.18, and 1.28 ms for gasoline, G9C1, and CNG, respectively. Flame velocities are 28.52, 30.93, and 34.11 m/s for CNG, G9C1, and gasoline, respectively, at 2800 r/min and Φ = 1.1. When the time between ignition moment and top dead center moment is considered, the increment rate of flame center temperature is 904.19, 884.10, and 861.77 K/s for CNG, gasoline, and G9C1, respectively. The highest temperature increment rate occurs for CNG.

YONTAR, AHMET ALPER/0000-0002-5453-5137; Dogu, Yahya/0000-0003-0474-2899 WOS: 000438692100013 In this study, a dual sequential spark ignition engine is separately tested either with gasoline or CNG at low and high loads. In addition, numerical engine analyses are performed by constructing a 1-D engine model in Ricardo-Wave software. Engine performance parameters in catalogue are generally given at full load conditions. However, during engine lifetime, vehicle engines rarely run at full load (wide open throttle) while engines work especially at the partial throttle openings. Engine characteristics (engine performance and exhaust emissions) are strong functions of throttle opening level. For this reason, determining engine characteristics at partial throttle openings at which engine mostly runs provides valuable information. In this study, partial throttle openings of 25% and 75% defined as low and high load conditions are examined for gasoline and CNG, as well. For this aim, the Honda L13A4 i-DSI (intelligent dual sequential ignition) engine was tested and engine characteristics were measured. This engine has unique features of dual sequential ignition with variable timing, asymmetrical combustion chamber, and diagonally positioned spark-plugs. Tests and numerical analyses were performed at specified low and high load conditions for gasoline and CNG by varying the engine speed from 1500 rpm to 4000 rpm with an increment of 500 rpm without excepting 2800 rpm. Engine characteristics were determined for the investigated parameters. Tests and 1-D model results are fairly matching each other. The average deviation between them is about 5.4%. Results show that the maximum torque for gasoline at 2800 rpm and 100% throttle opening reduced 12.6% and 26.3% for throttle openings of 75% and 25%, respectively. Compared to gasoline, CNG reduced the torque 15.6% and 19.6% for throttle openings of 75% and 25%, respectively. In general, CNG usage decreases all engine performance parameters (torque, power, volumetric efficiency, specific fuel consumption) and emissions (CO2, HC), except NOx formation. Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey; Yenmak Automotive Inc., Konya, Turkey This work was supported by the Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey; and Yenmak Automotive Inc., Konya, Turkey.

Dogu, Yahya/0000-0003-0474-2899; YONTAR, AHMET ALPER/0000-0002-5453-5137; Kantaroglu, Emrah/0000-0002-6127-4318 WOS:000555214900001 A commercial i-DSI (Intelligent-Dual Sequential Ignition) engine is tested to investigate performance and emissions for single fuels and alternative fuels mixed into gasoline. The novelty of the study is the first time testing of the unconventional mixture of boron derivatives and quantification and comparison of real engine characteristics for 11 different fuels for the same commercial engine. Tested single fuels are gasoline (G100), CNG (CNG100), and LPG (LPG100). While the engine runs with gasoline, gaseous fuels are injected into the intake line at a mass rate of 10% CNG (CNG10) and 5% LPG (LPG5). The engine is also tested by adding 25-50% acetone (A25-A50) and 50% naphthalene (N50) into gasoline. Tests are also performed by mixing boron derivatives of borax-pentahydrate (BP), anhydrous-borax (AB), and boric-acid (BA) into gasoline. Tested fuels worsen engine performance compared to gasoline, except for brake specific fuel consumption (BSFC). There is a positive change in emissions for tested fuels compared to gasoline, except that NOx increases 4-5 times for CNG and LPG. One of the important findings is that, for boron-gasoline mixtures, the torque reduces by 4.0% for BP, 4.4% for AB, and 4.4% for BA. The volumetric efficiency decreases by 6.3% for BP, 7.3% for AB, and 8.5% for BA. The BSFC decreases 5.8% for BP, increases 0.4% for AB and decreases 15.2% for BA. Boron derivatives dissolved in gasoline diversely affect combustion and give some advantage in particular for BA and BP in terms of BSFC. In addition, boron-gasoline reduces the formation of HC and NOx. Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey This work was supported by the Scientific Research Coordination Unit of Kirikkale University, Kirikkale, Turkey.

The pre-chamber ignition technology is a good solution that can make spark-ignition engines gradually more efficient. The novelty of the study is the testing of the pre-chamber jet ignition according to detailed air-fuel mixture range and fuel injection rates by combustion chambers. The main points in using this pre-chamber jet ignition were to observe the effect of reducing fuel consumption and emission formation. The tests were carried out for 0.80-1.80 lambda ranges and the pre-chamber injection/main chamber injection mass ratio ranges. A commercial RON 98 fuel was used at two ignition modes in tests for 5000 rpm high engine speed. At the pre-chamber jet ignition usage, the in-cylinder pressure for 1.00 lambda is overall 1.78% and 19.89% higher than the 0.80 lambda and the 1.80 lambda. The brake specific fuel consumption is about 8.67% lower than the spark-plug ignition usage at 0.80-1.20 lambda range. The HC formation is overall 8.12% lower than the spark-plug usage. The NOx formation for the spark-plug ignition is approximately 53.97% higher than the pre-chamber jet ignition usage as the temperature in-cylinder is high. The pre-chamber jet ignition was led to a much shorter flame development time and better combustion stability than the spark-plug. (C) 2020 Elsevier Ltd. All rights reserved.

The study focused on the effects of lambda, injection duration and start of injection on the diesel jet engine characteristics and also a challenge study for alternative fuels that have similar properties. The high-speed behaviors of the diesel jet test engine at full load were examined experimentally for diesel, JP-8, FAME, and naphtha. The tests were carried out for variations of 1.0–4.0 lambda, 5°–30° injection duration and 4°–20° start of injection. The experimental results were shown comparatively that the trends of sensitivity and behavior for diesel, JP-8, FAME, and naphtha according to variations of the measurement parameters. The behavior of in-cylinder pressure curves showed that FAME was less affected by lambda change than the other fuels. The most affected fuel from the timing of injection was the naphtha for heat release rate. The injection duration variations more positively affected the brake thermal efficiency for FAME than other tested fuels. The FAME was yielded the highest brake specific fuel consumption for the lambda range. At ultra-lean condition, the ignition delay time of naphtha was about 32.27% higher than the other fuels. While the start of injection point increased from 4° to 20°, CO emissions were reduced by about 60% for naphtha usage. The FAME usage had the highest slope and had more sensitivity than other fuels for injection duration variations. The most affected fuel from the start of injection parameter was the diesel for NOx formation. The most extreme sensitivity to injection duration was naphtha for particulate matter formation.

The effects of ethanol and E85 usages on engine performance characteristics have been numerically investigated at a dual sequential spark ignition engine. The Honda L13A4 i-DSI (Intelligent-Dual Sequential Ignition) engine (intake-exhaust manifold connections, intake-exhaust lines, intake-exhaust valves, cylinder, cylinder head, piston, spark-plugs, throttle etc.) was modeled in Ricardo-Wave software for ethanol and E85 usages taking into account all components related to the engine. In the analysis, engine speeds ranging from 1000 rpm to 6000 rpm with an increment of 500 rpm, throttle angle ranging from 22.5° to 90° with an increment of 2.5°, 10.8:1 compression ratio, 0.9 air-fuel ratio were adjusted. In the 1-D model, performance maps were generated using the data obtained as a result of the analyzes. As a result of the study, E85 has been observed to perform better than ethanol usage for the Honda L13A4 i-DSI that the engine designed for the usage of gasoline.

YONTAR, AHMET ALPER/0000-0002-5453-5137; Dogu, Yahya/0000-0003-0474-2899 WOS: 000444254500007 Compared to widening usage of CNG in commercial gasoline engines, insufficient but increasing number of studies have appeared in open literature during last decades while engine characteristics need to be quantified in exact numbers for each specific fuel converted engine. In this study, a dual sequential spark ignition engine (Honda L13A4 i-DSI) is tested separately either with gasoline or CNG at wide open throttle. This specific engine has unique features of dual sequential ignition with variable timing, asymmetrical combustion chamber, and diagonally positioned dual spark-plug. Thus, the engine led some important engine technologies of VTEC and VVT. Tests are performed by varying the engine speed from 1500rpm to 4000rpm with an increment of 500rpm. The engine's maximum torque speed of 2800rpm is also tested. For gasoline and CNG fuels, engine performance (brake torque, brake power, brake specific fuel consumption, brake mean effective pressure), emissions (O-2, CO2, CO, HC, NOx, and lambda), and the exhaust gas temperature are evaluated. In addition, numerical engine analyses are performed by constructing a 1-D model for the entire test rig and the engine by using Ricardo-Wave software. In the 1-D engine model, same test parameters are analyzed, and same test outputs are calculated. Thus, the test and the 1-D engine model are employed to quantify the effects of gasoline and CNG fuels on the engine performance and emissions for a unique engine. In general, all test and model results show similar and close trends. Results for the tested commercial engine show that CNG operation decreases the brake torque (12.7%), the brake power (12.4%), the brake mean effective pressure (12.8%), the brake specific fuel consumption (16.5%), the CO2 emission (12.1%), the CO emission (89.7%). The HC emission for CNG is much lower than gasoline. The O-2 emission for CNG is approximately 55.4% higher than gasoline. The NOx emission for CNG at high speeds is higher than gasoline. The variation percentages are the averages of the considered speed range from 1500rpm to 4000rpm. Scientific Research Projects Coordination Unit of Kirikkale University through the Automotive Research Laboratory at the Mechanical Engineering Department [2015/100, 2015/101] This work was partially funded by Scientific Research Projects Coordination Unit of Kirikkale University under project numbers of 2015/100 and 2015/101 through the Automotive Research Laboratory at the Mechanical Engineering Department.

The effects of the flame radius and flame propagation have been investigated at a sequential ignition engine with numerically. A single cylinder of the sequential ignition engine was modeled in STAR-CD/es-ice software for the gasoline usage taking into account all components related to the combustion chamber. The effect of flame on engine characteristics is the function of flame radius and flame thickness. In the numerical analysis, compression ratio is 10.8:1, air-fuel ratio is 1.2, ignition advance at 30-25 CAD, engine speed is 3000 rpm and the flame thickness is 0.0001 m were kept constant. The analysis, k-e RNG turbulence model, Angelberger wall interaction and G-equation combustion model were used and optimum flame radius value was determined. Three different analysis were carried out to determine the effect of the flame radius and the flame radius was changed to 0.0005 m, 0.0010 m and 0.0020 m, respectively. As a result of the study, images of flame formation and propagation were obtained for the time period up to the top dead center at the time of sequential ignition. The effects of flame radius on CO2 formation and NOx formation were evaluated. The net work area was obtained from the highest engine power and pressure-volume graph when the flame radius was 0.0010 m for the specified operating conditions.

5th International Conference on Transportation and Traffic Engineering (ICTTE) -- JUL 06-10, 2016 -- Univ Lucerne, Lucerne, SWITZERLAND Dogu, Yahya/0000-0003-0474-2899; YONTAR, AHMET ALPER/0000-0002-5453-5137 WOS: 000387184100056 In this study, a spark-ignition engine fuelled with gasoline and LNG was modelled in 1-D at wide open throttle by using Ricardo-Wave software. Different engine speeds ranging from 1500rpm to 4500rpm with an increment of 500rpm were studied to evaluate the effects of gasoline and LNG on engine performance and exhaust emissions. It is determined that LNG decreases engine performance and emissions as well, at especially high speeds.