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The Ultra Low Emissions Potential of the Recuperated Split Cycle Combustion System

Dolphin N2 Ltd-Nicholas Owen
Ricardo UK Ltd-Andrew Atkins, Rhys Pickett
  • Technical Paper
  • 2019-24-0189
To be published on 2019-08-15 by SAE International in United States
The recuperated split cycle engine is a fundamentally new class of internal combustion engine that offers a step change is thermal efficiency over conventional Otto and Diesel cycle engines – 50% brake thermal efficiency in its simplest form, approaching 60% with intensively cooled compression. The technology targets the heavy duty, long-haul sector where electrification is most challenging. In a split cycle engine, the compression and expansion strokes are performed in different cylinders. Waste exhaust heat is recovered between the compression and combustion cylinders via a recuperator which gives precise control of the charge temperature. Recent experimental and analytical research has shown the split cycle combustion system also has the potential to achieve ultra-low emissions. Experimental studies on a one litre single cylinder research engine, representative of a typical medium duty truck engine have showed engine out NOx emissions of less than 110ppm at mid speed – mid load, typical of a motorway cruise condition. Rigorous analysis of the impact of applying an SCR based aftertreatment system showed tailpipe NOx emissions of less than 5ppm are…
 

Simultaneous optimization of real-time control strategies and powertrain design for fuel cell hybrid vehicles

University of Salerno-Marco Sorrentino, Dario Capaldo
  • Technical Paper
  • 2019-24-0199
To be published on 2019-08-15 by SAE International in United States
Developing successful fuel cell hybrid vehicles (FCHVs) is nowadays considered as a highly strategic target to fully meet well known environmental and regulatory constraints. This is due to the potentially superior features of fuel cell propulsion as compared to both electric and hybrid vehicles, such as high fuel-economy, reduced tank-to-wheel environmental impact and appreciably long ranges. Successful achievement of the above-introduced challenging goal fully motivates the development of advanced mathematical tools featuring co-optimization capabilities, so as to adequately account for the strong interactions and mutual influence between design criteria and selected control strategies. To this aim, a comprehensive model of a generic FCHV architecture and a specification independent control strategy were integrated within a modular constrained optimization algorithm, which was conceived in such a way as to simultaneously find the optimal FCHV powertrain design and associated real-time applicable control strategies. Suitable design and energy management criteria, accounting for also the impact of a-priori knowledge of driving mission on proper management of available power sources, were selected. The proposed co-optimization procedure aims at determining both key…
 

A practical Recuperated Split Cycle engine for low emissions and high efficiency

Dolphin N2 Ltd-Fabrizio Treccarichi
Dolphin N2, Ltd.-Nicholas John Owen
  • Technical Paper
  • 2019-24-0190
To be published on 2019-08-15 by SAE International in United States
The Recuperated Split Cycle Engine is a new type of ICE, offering a step change in efficiency and tailpipe emissions. It targets the heavy duty, long-haul sector (trucks, rail, shipping), where electrification is most challenging, and distributed generation, where capacity is required to support rising electrification. The engine separates cold (induction, compression) and hot (combustion, expansion) parts of the cycle; waste exhaust heat is recovered between them via a recuperator, as in a recuperated gas turbine. Recent research presented in another paper at this conference shows that the sonic airflows seen in the induction event give rise to extraordinary fuel mixing and clean, cool combustion, with potential for after-treated emission levels between SULEV and zero-impact (either unmeasurable or below ambient). However, recuperation and thermal insulation of the hot cylinder also enable high thermal efficiency, with a much flatter efficiency map than a conventional ICE. Combining the two attributes, and introducing sustainable fuels, places this readily manufactured, affordable technology on a par with battery-electric and fuel cell propulsion. Results from simulation to optimise the concept are…
 
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Toyota's proven fuel-cell stack reduces cost, complexity in H2 semi-truck

SAE Truck & Off-Highway Engineering: June 2019

Sebastian Blanco
  • Magazine Article
  • 19TOFHP06_14
Published 2019-06-01 by SAE International in United States

Hydrogen proponents likely know that Mirai means “future” in Japanese, but Toyota is only just beginning to explore how important the fuel cell stack in its H2-powered passenger car will be to the future of the company.

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HYDROGEN BOOM!

SAE Truck & Off-Highway Engineering: June 2019

Ryan Gehm
  • Magazine Article
  • 19TOFHP06_05
Published 2019-06-01 by SAE International in United States

Nikola reveals Two and Tre fuel-cell trucks and its H2 fueling roadmap, as well as battery-electric military and powersports vehicles.

On-highway Class 6-8 trucks are Nikola's main business and engineering focus, but the Arizona-based startup is expanding its product range to include powersports and military sectors to demonstrate its technology's adaptability. In addition to the Nikola Two and Tre hydrogen fuel-cell trucks for North America and Europe, respectively, the manufacturer revealed a battery-electric all-terrain vehicle, an autonomous-capable military vehicle and a personal-watercraft concept to about 2,000 attendees of the Nikola World opening event in Scottsdale, Ariz., near the company's Phoenix headquarters.

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Comparative Study of Different Air Supply Systems for Automotive Fuel Cell Applications

SAE International Journal of Alternative Powertrains

Continental Automotive GmbH, Germany-Florian Uhrig, Mario Schinnerl, Peter Haluska, Peter Kurzweil, Thomas von
  • Journal Article
  • 08-08-01-0002
Published 2019-05-10 by SAE International in United States
The dynamic and efficiency of automotive fuel cell drives is significantly influenced by air supply system. Different air compression architectures use electric compressor (EC), electric turbocharger (ETC), or a serial booster (SB) consisting of turbocharger and electric compressor. These three variants of air compression systems were modeled using a map approach and added to a 0D fuel cell air supply model. The characteristic maps of the turbomachinery were measured on the test bench under fuel cell conditions. Subsequently, the calculated isentropic efficiencies were corrected with respect to heat transfer phenomena occurring during the measurement. Moreover, a scaling method for the maps of the turbomachinery is explained. The initial simulation of the air compression systems with equal diameters for the turbomachinery showed no difference in the mechanical power demand. Therefore, the particle swarm algorithm (PSA) was applied to optimize the turbomachinery maps of EC, ETC, and SB with the scaling method. The PSA reduces the mechanical power demand of EC by 17%, of ETC by 18%, and of SB by 27%. This leads to the lowest…
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JAUS Unmanned Ground Vehicle Service Set

AS-4JAUS Joint Architecture for Unmanned Systems Committee
  • Aerospace Standard
  • AS6091
  • Current
Published 2019-04-22 by SAE International in United States
This document defines a set of standard application layer interfaces called JAUS Unmanned Ground Vehicle Services. JAUS Services provide the means for software entities in an unmanned system or system of unmanned systems to communicate and coordinate their activities. The Unmanned Ground Vehicle Services represent the platform-specific capabilities commonly found in UGVs, and augment the Mobilty Service Set [AS6009] which is platform-agnostic. At present ten (10) services are defined in this document. These services are categorized as:
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Experimental PEM-Fuel Cell Range Extender System Operation and Parameter Influence Analysis

Vienna University of Technology-Johannes Höflinger, Peter Hofmann, Bernhard Geringer
Published 2019-04-02 by SAE International in United States
Fuel cells as alternative propulsion systems in vehicles can achieve higher driving ranges and shorter refueling times compared to pure battery-electric vehicles, while maintaining the local zero-emission status. However, to take advantage of pure battery electric driving, an externally rechargeable battery can be combined with a fuel cell range extender. As part of a research project, an efficient air supply system for a fuel cell range extender was developed. To this end, a 25 kW PEM fuel cell system test bench was set up. The different parameter influences of the test bench, in particular of the air supply system, were analyzed and evaluated in terms of stack/system efficiency and functionality. The control software of the test bench was specifically developed for the flexible operating parameter variation. All adjustable variables of the system (air ratio, stack temperature, pressure, etc.) were varied and evaluated at steady-state operating points. Likewise, the system was analyzed during dynamic operation and fault cases in adverse operating conditions (water condensation, oxygen deficiency) were identified. The system's warm-up process was also evaluated in…
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Voltage and Voltage Consistency Attenuation Law of the Fuel Cell Stack Based on the Durability Cycle Condition

CATARC-Dong Hao
Shanghai Motor Vehicle Inspection Center-Fenglai Pei
Published 2019-04-02 by SAE International in United States
Based on the durability cycle test of fuel cell stack and the characteristics of cyclic working conditions, this paper defines the characteristic current point and studies the attenuation rule of the fuel cell stack voltage over time under the characteristic current point. The results show that the voltage of the fuel cell stack appears to be linear downward under the characteristic current point. and the voltage attenuation rate of the fuel cell stack increases quadratically with the increase of the current density in addition to the open-circuit voltage point. Then the coefficient of variation is introduced in statistics as the index to characterize the voltage consistency attenuation of the fuel cell stack, and its variation rule is explored. The results show that the voltage consistency of vehicle fuel cell stack decreases seriously with the increase of running time under the condition of durable cycling.
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A Quasi-2D Transient Multiphase Modeling of Cold Start Processes in Proton Exchange Membrane Fuel Cell

Tianjin University-Kangcheng Wu, Kui Jiao, Bingfeng Zu
Published 2019-04-02 by SAE International in United States
It’s well known that startup process of proton exchange membrane fuel cells (PEMFCs) under subzero temperature is extremely significant because of its influence on fuel cell performance and durability. In the study, a quasi-2D numerical model is developed and dynamic equations of mass conservation, energy conservation, membrane water conservation, ice conservation, species conservation are all considered. Three different hydrogen supply modes are studied in detail: flow-through anode (FTA) mode, dead-ended anode (DEA) mode and off-gas recirculation (OR) mode. It is found that the local current density (LCD) and temperature distribution vary remarkably along flow channel in OR mode as t > 500s due to nitrogen crossover and accumulation. During the cold start operation, the DEA mode and OR mode hold more water in anode catalyst layer (ACL) which reduces the effects of hydraulic permeation, resulting in more ice formation in cathode catalyst layer (CCL) and slower temperature rising. In term of hydrogen utilization ratio, the efficiencies in DEA mode and OR mode are close and much better than that in FTA mode. Compared with DEA…
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