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A Fundamental study on the effects of Electrically Heated Catalyst on State of Charge of the battery pack for a series hybrid electric vehicle at cold start.

Waseda University-Suchitra Sivakumar, Hajime Shingyouchi, Xieyang Yan, Toshinori Okajima, Kyohei Yamaguchi, Jin Kusaka
NE Chemcat Corp.-Makoto Nagata
  • Technical Paper
  • 2020-01-0444
To be published on 2020-04-14 by SAE International in United States
Battery models are recently being developed as one of a component of the powertrain system of Hybrid Electric Vehicle (HEV) to predict the State of Charge (SOC) accurately. The electric components like the Electrically Heated Catalyst (EHC) which is used to reach the catalyst light off temperature in advance are being employed in the powertrain of HEVs. The EHC draws power from the battery pack of the HEV. Therefore, sufficient energy should be stored in the battery pack of an HEV to power the auxiliary components in the powertrain. In a series hybrid electric vehicle system, the engine is primarily used to charge the battery pack. Therefore, it is important to develop a control strategy that triggers the engine start/stop conditions and reduces the frequency of engine operation to minimize the equivalent fuel consumption. A battery pack model was constructed in MATLAB-Simulink to investigate the SOC variation of a high-power lithium ion battery during extreme engine cold start conditions (-7°C) with and without the application of EHC. An electrically heated catalyst (EHC) was also simulated…
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Two prototype engines with colliding and compression of pulsed supermulti-jets through a focusing process, leading to nearly complete air insulation and relatively silent high compression for automobiles, motorcycles, aircrafts, and rockets

Waseda University-Remi Konagaya, Ken Naitoh, Tomotaka Kobayashi, Yuuki Isshiki, Hajime Ito, Hiroki Makimoto, Yoshiki Kobayashi, Yusuke Tada, Nozomu Kikuchi, Aya Hosoi, Yuto Fujii
  • Technical Paper
  • 2020-01-0837
To be published on 2020-04-14 by SAE International in United States
We have proposed a new compressive combustion principle based on pulsed supermulti-jets colliding through focusing process, by injection from chamber wall to chamber center. This principle has potential of relatively-silent high compression around chamber center because of auto-ignition far from chamber wall and nearly-complete air insulation due to encasing of burned high temperature gas. The present principle leading to higher thermal efficiency and higher power will be applicable for automobiles, aircrafts, rockets, and also flying cars to be realized in the future. Then, water cooling system made smaller or even eliminated will result in lower price, while auto-ignition in an area larger than that created by traditional spark-ignition will lead to less NOx emission at very lean burning. Thus, we here show four new evidences based on experimental data and computational and theoretical considerations. (1) Quantitative clarification of compression level at condition without combustion (2) Atomization effect due to high-speed jets reducing fuel tank pressure (3) Combustion experiments in piston-less engine having pulsed 14-focusing jets colliding (1st prototype engine for checking this compressive combustion principle),…
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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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Analysis of NH3 Diffusion Phenomena in a Selective Catalytic Reduction Coated Diesel Particulate Filter Catalyst Using a Simple One-Dimensional Core Model

Waseda University-Ken Sahara, Yoshihisa Tsukamoto, Akihisa Ishimaru, Takao Fukuma, Jin Kusaka
  • Technical Paper
  • 2019-01-2236
Published 2019-12-19 by SAE International in United States
This paper describes a method for estimating constants related to NH3 gas diffusion phenomena to the active sites in a selective catalytic reduction diesel particulate filter (SCR/DPF) catalyst. A simple one-dimensional NH3 gas diffusion model based on the pore structure inside the catalyst was developed and used to estimate the intracrystalline diffusion coefficient. It was shown that the estimated value agreed well with experimental data.
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Modeling Three-Way Catalyst Converters During Cold Starts And Potential Improvements

Waseda University-Xieyang Yan, Ryota Sone, Ryoya Inoue, Jin Kusaka
AZAPA Co. LTD-Katunori Umezawa, Yasuhiro Kondo
  • Technical Paper
  • 2019-01-2326
Published 2019-12-19 by SAE International in United States
Three-way catalyst (TWC) converters are often used to purify toxic substances contained in exhaust emissions from gasoline engines. However, a large amount of CO, NOx and THC may be emitted before the TWC reaches its light-off temperature during a cold start. In this work, a numerical model was developed for studying the purification performance of a close-coupled TWC converter during the cold start period. The TWC model was built using axisuite, commercial software by Exothermia S.A. Model gas experiments were designed for calibrating the chemical reaction scheme and corresponding reaction rate parameters in the TWC model. The TWC model was able to simulate the purification performance of CO, NOx and THC under both lean and rich air-fuel equivalence ratios (λ) for different conditions. The light-off temperature and oxygen storage capacity (OSC) behavior were also successfully validated in the model. Vehicle tests were conducted on a chassis dynamometer to verify the TWC model. The simulation achieved good agreement with the experimental data during a cold start. Based on the validated model, a parametric analysis was conducted…
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Attainment of High Thermal Efficiency and Near-zero Emissions by Optimizing Injected Spray Configuration in Direct Injection Hydrogen Engines

Waseda University-Ken Naitoh
Okayama University-Nobuyuki Kawahara, Eiji Tomita
  • Technical Paper
  • 2019-01-2306
Published 2019-12-19 by SAE International in United States
The authors have previously proposed a plume ignition and combustion concept (i.e., PCC combustion), in which a hydrogen fuel is directly injected to the combustion chamber in the latter half of compression stroke and forms a richer mixture plume. By combusting the plume, both cooling losses and NOx formation are reduced. In this study, thermal efficiency was substantially improved and NOx formation was reduced with PCC combustion by optimizing such characteristics as direction and diameter of the jets in combination with combustion of lean mixture. Output power declined due to the lean mixture, however, was recovered by supercharging while keeping NOx emissions at the same level. Thermal efficiency was further improved by slightly re-optimizing the jet conditions. The results showed that the hydrogen engine can attain near-zero emissions of NOx reduced to the single-digit ppm level with high thermal efficiency close to 50 percent and can thus be truly called a near-zero emission engine.
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A Fundamental Study on Combustion Characteristics in a Pre-Chamber Type Lean Burn Natural Gas Engine

Waseda University-Masashi Tanamura, Shintaro Nakai, Mahoko Nakatsuka, Shota Taki, Kohei Ozawa, Beini Zhou, Ratnak Sok, Yasuhiro Daisho, Jin Kusaka
Published 2019-09-09 by SAE International in United States
Pre-chamber spark ignition technology can stabilize combustion and improve thermal efficiency of lean burn natural gas engines. During compression stroke, a homogeneous lean mixture is introduced into pre-chamber, which separates spark plug electrodes from turbulent flow field. After the pre-chamber mixture is ignited, the burnt jet gas is discharged through multi-hole nozzles which promotes combustion of the lean mixture in the main chamber due to turbulence caused by high speed jet and multi-points ignition. However, details mechanism in the process has not been elucidated.To design the pre-chamber geometry and to achieve stable combustion under the lean condition for such engines, it is important to understand the fundamental aspects of the combustion process. In this study, a high-speed video camera with a 306 nm band-pass filer and an image intensifier is used to visualize OH* self-luminosity in rapid compression-expansion machine experiment. The results show that the OH* self-luminosity is observed in outer edge of the jet, while the luminosity in the jet temporarily weakens because the turbulent jet is exposed to low temperature surrounding in the…
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Computational Optimization of Pressure Wave Reflection on the Piston Surface for Single Point Autoignition Gasoline Engine with Colliding Pulsed Supermulti-Jets Leading to Noiseless-High Compression and Nearly-Complete Air-Insulation

Waseda University-Aya Hosoi, Remi Konagaya, Sota Kawaguchi, Yasuhiro Sogabe, Yuya Yamashita, Ken Naitoh
Published 2019-04-02 by SAE International in United States
A new engine concept based on pulsed supermulti-jets colliding at a small area around the chamber center was proposed in our previous research. It was expected to provide noiseless high compression ratio and nearly-complete air-insulation on chamber walls, leading to high thermal efficiency. In the previous reports, three-dimensional computations for the unsteady compressible Navier-Stokes equation were conducted, which were qualitative because of using regular grid method. This time, we develop a new numerical code in order to quantitatively simulate the compression level caused by the jets colliding with pulse. It is achieved by applying a staggered grid method to improve conservatibity of physical quantities at very high compression in combustion phenomena. Computations at a simple condition were fairly agreed with a theoretical value. Computational results obtained for a complex geometry of an engine by the new code had less error than one with previous codes. In addition, the results led us to an idea of new disposition of nozzles to achieve higher compression ratio. Furthermore, we tried to optimize the effect of pressure wave reflection…
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0D/1D Turbulent Combustion Model Assessment from an Ultra-Lean Spark Ignition Engine

Waseda University-Ratnak Sok, Kyohei Yamaguchi, Jin Kusaka
Published 2019-03-25 by SAE International in United States
This paper focuses on an assessment of predictive combustion model using a 0D/1D simulation tool under high load, different excess air ratio λ , and different combustion stabilities (based on coefficient of variation of indicated mean effective pressure COVimep). To consider that, crank angle resolved data of experimental pressure of 500 cycles are recorded under engine speed 1000 RPM and 2000 RPM, wide-open throttle, and λ=1.0, 1.42, 1.7, and 2.0. Firstly, model calibration is conducted using 18 cases at 2000 RPM using 500 cycle-averaged in-cylinder pressure to find optimized model constants. Then, the model constants are unchanged for other cases. Next, different cycle-averaged pressure data are used as inputs in the simulation based on the COVimep for studying sensitivity of the turbulent model constants.The simulation is conducted using 1D simulation software GT-Power. Firstly, a three-pressure analysis (TPA) model (intake, in-cylinder, exhaust) for experimental prediction and optimization of burn rate shape are studied. Boundary conditions such as the three pressure histories, intake/exhaust valves timings, boundary temperatures, and exhaust gas emissions are used as model inputs. Errors of…
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Kinetic Modeling of Ammonia-SCR and Experimental Studies over Monolithic Cu-ZSM-5 Catalyst

Waseda University-Jin Kusaka
Hokkaido University-Wataru Eijima, Gen Shibata, Yoshimitsu Kobashi, Ryutaro Koiwai, Hideyuki Ogawa, Kenichi Shimizu
Published 2019-01-15 by SAE International in United States
Ammonia-selective catalytic reduction (SCR) systems have been introduced commercially in diesel vehicles, however catalyst systems with higher conversion efficiency and better control characteristics are required to know the actual emissions during operation and the emissions in random test cycles. Computational fluid dynamics (CFD) is an effective approach when applied to SCR catalyst development, and many models have been proposed, but these models need experimental verification and are limited in the situations they apply to. Further, taking account of redox cycle is important to have better accuracy in transient operation, however there are few models considering the cycle. Model development considering the redox reactions in a zeolite catalyst, Cu-ZSM-5, is the object of the research here, and the effects of exhaust gas composition on the SCR reaction and NH3 oxidation at high temperatures are investigated. The simulations are compared with the experimental results of a surrogate gas, a mixture of nitrogen monoxide (NO), oxygen (O2), water vapor (H2O), and nitrogen (N2), and the accuracy of the developed model is validated. To investigate the effects of O2…
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