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High Efficiency by Miller Valve Timing and Stoichiometric Combustion for a Naturally Aspirated Single Cylinder Gas Engine

Karlsruhe University of Applied Sciences-Jörn Judith, Denis Neher, Maurice Kettner
SenerTec Kraft-Wärme-Energiesysteme GmbH-Danny Schwarz, Markus Klaissle
  • Technical Paper
  • 2019-32-0588
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Small-scale cogeneration units (Pel < 50 kW) frequently use lean mixture and late ignition timing to comply with current NOx emission limits. Future tightened NOx limits might still be met by means of increased dilution, though both indicated and brake efficiency drop due to further retarded combustion phasing and reduced brake power. As an alternative, when changing the combustion process from lean burn to stoichiometric, a three-way-catalyst allows for a significant reduction of NOx emissions. Combustion timing can be advanced, resulting in enhanced heat release and thus increased engine efficiency.Based on this approach, this work presents the development of a stoichiometric combustion process for a small naturally aspirated single cylinder gas engine (Pel = 5.5 kW) originally operated with lean mixture. To ensure low NOx emissions, a three-way-catalyst is used. In order to achieve high engine efficiency, measures implemented include Miller valve timing, optimized intake system, reduced engine speed and increased compression ratio. In the first step, a detailed 1D engine cycle simulation model was used to investigate the efficiency benefit of Miller valve timing…
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Numerical Studies on Temporal and Spatial Distribution of Equivalence Ratio in Diesel Combustion Using Large Eddy Simulation

Waseda University-Beini Zhou, Shotaro Yamada, Takayuki Adachi, Jin Kusaka
  • Technical Paper
  • 2019-32-0599
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
To identify ways of achieving good mixture formation and heat release in diesel spray combustion, we have performed Large Eddy Simulation (LES) using a detailed chemical reaction mechanism to study the temporal and spatial distribution of the local equivalence ratios and heat release rate. Here we characterize the effect of the fuel injection rate profile on these processes in the combustion chamber of a diesel engine. Two injection rate profiles are considered: a standard (STD) profile, which is a typical modern common rail injection profile, and the inverse delta (IVD) profile, which has the potential to suppress rich mixture formation in the spray tip region. Experimental data indicate that the formation of such mixtures may extend the duration of the late combustion period and thus reduce thermal efficiency. Analyses of the heat release per unit fuel mass and unit entrained O2 mass under the two injection regimes indicate that IVD injection reduces the density of the fuel-air mixture in the spray tip region, increases the leanness of the spray core region, and enhances O2 entrainment,…
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Sensor Integrated Substrate for Future Exhaust System of Two Wheelers

Vitesco Technologies Japan. K.K., Vitesco Technologies Emite-KOSAKU ITO, SVEN SEIFERT, FRANCOIS JAYAT, THOMAS CARTUS
  • Technical Paper
  • 2019-32-0617
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
By upcoming new global two wheelers emission legislation, it is expected that it will become more and more challenging to control exhaust emissions. Therefore, not only optimized catalyst specifications to meet OBDII or RDE, but also new components will be required for future applications in two-wheeler exhaust systems. In such applications, beneath applying new components, it is necessary to ensure mountability while maintaining vehicle design but improving function of the exhaust system at the same time. As exhaust system layout of two wheelers is generally strongly limited by many factors, such as steeply bended exhaust pipes and catalysts which are hard to resize, one of the most challenging tasks is the positioning of sensor behind the catalyst, due to two wheelers unique exhaust design. In order to overcome the challenge, this work describes designs like the catalyst with integrated lambda sensor, which is developed to contribute to high efficient future two wheelers exhaust systems.
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Study of Rider Model for Motorcycle Racing Simulation

Honda Racing Corporation-Masatsugu Nishimura, Yoshitaka Tezuka
Università degli Studi di Padova-Enrico Picotti, Mattia Bruschetta
  • Technical Paper
  • 2019-32-0572
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Various rider models have been proposed that provide control inputs for the simulation of motorcycle dynamics.However, those models are mostly used to simulate production motorcycles, so they assume that all motions are in the linear region such as those in a constant radius turn. As such, their performance is insufficient for simulating racing motorcycles that experience quick acceleration and braking.Therefore, this study proposes a new rider model for racing simulation that incorporates Nonlinear Model Predictive Control. In developing this model, it was built on the premise that it can cope with running conditions that lose contact with the front wheels or rear wheels so-called "endo" and "wheelie", which often occur during running with large acceleration or deceleration assuming a race. For the control inputs to the vehicle, we incorporated the lateral shift of the rider's center of gravity in addition to the normally used inputs such as the steering angle, throttle position, and braking force.We compared the performance of the new model with that of the conventional model under constant radius cornering and straight braking,…
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Replacement of a 50cc Two-stroke Engine with an Electric Powertrain

TWIG Power-Jesse Beeker
  • Technical Paper
  • 2019-32-0623
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
As global regulations look to create a dramatic reduction in CO2 emission and other forms of pollution, companies with products that rely on engine technology must be ready to take on the electrification challenge. Applications that remain using two-stroke engine technology continue to exist due to their very high power density requirements. However, their history of higher pollution compared to four-stroke engines makes them a target to be regulated out of existence.Such high power two-stroke applications include high performance off-road motorcycles. In this type of product, electrification can solve not only pollution challenges but market challenges, such as ridership and public perception. By addressing the core problems presented by the two-stroke engine and turning challenges into opportunity, a strong attraction is created to convert a two-stroke engine motorcycle to an electric vehicle.With Automotive electric vehicle technology paving the way, the basis for cost effective electric motorcycle powertrain is explored for a 50cc off-road motorcycle application. The 50cc engine and motorcycle represent a special product where size, performance, and cost have a high sensitivity. The 50cc…
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Study for Higher Efficiency and Lower Emissions in Turbo Charged Small Gas Engine Using Low Caloric Biomass Model Gas

Doshisha University-Kenta Shiomi, Ryogo Kato, Eriko Matsumura, Jiro Senda
Yanmar Co.,Ltd-Ryoichi Hagiwara, Yuta Watanabe, Toru Nakazono
  • Technical Paper
  • 2019-32-0620
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
In recent years, depletion of energy resources and increasing CO2 emission have been concerned. As this solution, the use of biofuels from garbage is focused. In this research, higher efficiency and lower emissions in the gas engine for power generation using biomass gas are aimed. However, the biomass gas is low caloric value and the output is low and the combustion is unstable. Therefore, a turbocharged spark ignition gas engine is used as the test institution. As a result, it is found that combustion stability and high efficiency of biomass gas can be realized.
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Effects of Surface Compound Layer on Bending Fatigue Strength of Nitrided Chromium-Molybdenum Steel

Yamaha Motor Co., Ltd.-Tsuyoshi Kubota
Yokohama National University-Osamu Umezawa
  • Technical Paper
  • 2019-32-0504
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Carburized and quenched materials with high fatigue strength are often used for motorcycle engine parts. Nitrided materials exhibit less deformation during heat treatment than carburized and quenched materials, so if the same or higher fatigue strength can be achieved with nitrided materials as with carburized and quenched materials, the geometric precision of parts can be increased and we can reduce engine noise as well as power loss. When the fatigue strengths of a nitrided material with its compound layer surface put into γ’ phase through nitriding potential control (hereafter, G), and a nitrided material put into ε phase (hereafter, E) were measured, the results showed the fatigue strength of the G to be about 11% higher than that of carburized and quenched materials. It was inferred that the strength of the compound layer determines fatigue strength. The reason the fatigue strength of the G is higher is that initial cracks do not readily form, and it can be inferred that when cracks do form, they progress readily and lead to final fracture. In the case…
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Analysis of Cycle-to-Cycle Variation in a Port Injection Gasoline Engine by Simultaneous Measurement of Time Resolved PIV and PLIF

Chiba University-Tatsuya KUBOYAMA, Yasuo MORIYOSHI
Sustainable Engine Research Center Co., Ltd.-Satoshi HOKIMOTO
  • Technical Paper
  • 2019-32-0552
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Cycle-to-cycle variation (CCV) of combustion in low load operation is a factor that may cause various problems in engine operation. Variable valve timing and variable ignition timing are commonly used as a means to reduce this variation. However, due to mountability and cost constraints, these methods are not feasible for use in motorcycle engines. Therefore, development of an engine with minimal CCV without utilizing complicated mechanisms or electronic control is required. CCV of combustion may be caused by fluctuations in in-cylinder flow, air-fuel mixture, temperature, residual gas and ignition energy. In this study, the relationship between CCV of combustion, in-cylinder flow fluctuation and air-fuel mixture fluctuation was the primary focus. In order to evaluate in-cylinder flow fluctuation, Time Resolved Particle Image Velocimetry (TR-PIV) technique was utilized. In addition, Planar Laser Induced Fluorescence (PLIF) technique was used to measure spatial distribution of the mixture. These two visualization techniques were used together to measure continuous combustion cycles. The fluctuation of net IMEP can be explained by the fluctuation of Turbulence Kinetic Energy (TKE) and fuel concentration. In…
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Combustion Characteristic of Offset Orifice Nozzle under Multi Pulse Ultrahigh Pressure Injection and PCCI Combustion Conditions

Tokyo Institute of Technology-Pop-Paul Ewphun, Miku Otake, Tsuyoshi Nagasawa, Hidenori Kosaka, Susumu Sato
  • Technical Paper
  • 2019-32-0522
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
CI engines provide higher thermal efficiency compared to other internal combustion engines. On the other hand large amounts of smoke and NOx are produced during combustion. Smoke and NOx can be reduced by applying Premixed Charge Compression Ignition (PCCI) combustion. Unfortunately, the problems of PCCI combustion include unstable start of combustion and limited operating range. The multi-pulse ultrahigh pressure injection allows fuel to control PCCI combustion. The objective of offset orifice nozzle is to improve mixture formation and shorten spray penetration in order to increase thermal efficiency and control PCCI combustion. The offset orifice nozzle was designed by shift orifice aliment from into the sac center to edge of sac follow swirl direction. Counter bore design was applied to offset orifice nozzle in order to keep the constant orifice length as standard nozzle. This paper investigates the effect of nozzle orifice design on combustion characteristics under multi pulse ultra high pressure injection and PCCI combustion conditions. The experiments were carried out on a single cylinder engine at 0.55 MPa gross IMEP at 1,750 rpm. The…
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Development of a Novel Hybrid-Piston for Application in High Performance Two-Stroke Engines

Fraunhofer IWS, 01277 Dresden, Germany-Axel Jahn, Frieder Zimmermann, Uwe Stamm
Mahle König Kommanditgesellschaft GmbH &amp; Co KG, 6830 Ran-Christian Bechter, Thomas Herb
  • Technical Paper
  • 2019-32-0508
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
The current development trends for high performance two-stroke engines have been identified in raising combustion pressures and therefore higher cylinder temperatures [1] [2]. Thus, the requirements on piston assembly are increased in such a way that pistons based on aluminium-silicon alloys – as most commonly used in high performance two-stroke engines - reach their application limit. A suitable solution has been shown by research work such as that conducted by Mahle König, by using a piston consisting of different materials. With this approach, the higher stressed piston crown consists of steel, while the lower stressed piston skirt is made out from aluminium. Previous basic examinations showed the high potential of the hybrid piston concept in terms of pressure and temperature increase, while also showing the need for a temperature-stable and pressure-tight joint between crown and skirt.This paper will focus on the development of two novel hybrid-piston concepts, where the piston crown and the piston skirt are connected in different ways. The first hybrid concept presented uses the piston pin in order to realize a plugconnection…
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