Exploration of Dual Fuel Diesel Engine Operation with On-Board Fuel Reforming

Hwang, Jeffrey T.; Li, Xuesong; Northrop, William F.

doi:10.4271/2017-01-0757

Cited by 11 publications

(8 citation statements)

References 30 publications

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“…It can be challenging to operate the engine and catalyst systems together so that good performance of the catalytic reformer and engine are achieved simultaneously. Hwang et al 36 integrated a reforming catalyst containing Rh and Pt into the exhaust manifold of a diesel engine. While they were able to produce high concentrations of H 2 (>10%), the reforming system resulted in an overall engine efficiency decrease, because the reformer catalyst equivalence ratio was too low (Φ catalyst as low as 1.5), and the reforming process was too dependent on the exothermic reactions in eq 3.…”

Section: ■ Introductionmentioning

confidence: 99%

“…D-EGR uses fuel-rich combustion in one cylinder and recirculates its exhaust to the intake system, generating brake thermal efficiency as high as 42.5% and demonstrating a vehicle-level fuel consumption decrease of more than 10% . This category also includes injecting fuel during the negative valve overlap period for a homogeneous charge compression ignition engine to manipulate the fuel–air mixture autoignition propensity. − The second category of fuel reforming, and the category of the present work, is where a catalyst is used to reform the fuel outside of the engine cylinders. ,,− …”

Section: Introductionmentioning

confidence: 99%

“…Catalytic reforming processes often use the sensible enthalpy in the exhaust to promote reforming reactions over the catalyst to improve the energetics of reforming. ,,− ,− The range of possible combustion and reforming reactions that can occur has been presented by Ahmed and Krumpelt and by Jamal and Wyszynski, and is presented below for completeness using iso-octane as the starting fuel. Equation shows the reaction stoichiometry for the complete combustion of iso-octane, while eq defines equivalence ratio (Φ).…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 1: Catalyst Performance

et al. 2018

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The use of fuel reformate from catalytic processes is known to have beneficial effects on the spark-ignited combustion process through enhanced dilution tolerance and decreased combustion duration, but, in many cases, reformate generation can incur a significant fuel penalty. In this two-part investigation, we demonstrate that efficient catalytic fuel reforming can result in improved brake engine efficiency while maintaining stoichiometric exhaust under the right conditions. In Part 1 of this investigation, we used a combination of thermodynamic equilibrium calculations and experimental fuel catalytic reforming measurements on an engine to characterize the best possible reforming performance and energetics over a range of equivalence ratios and O2 concentrations. Ideally, one might expect the highest levels of thermochemical recuperation for the highest catalyst equivalence ratios. However, reforming under these conditions is highly endothermic, and the available enthalpy for reforming is constrained. Thus, for relatively high equivalence ratios, more methane and less H2 and CO are produced. Our experiments revealed that this suppression of H2 and CO could be countered by adding small amounts of O2, yielding as much as 15 vol % H2 at the catalyst outlet for 4 < Φcatalyst < 7 under quasi-steady-state conditions. Under these conditions, the H2 and CO yields were highest and there was significant water consumption, confirming the presence of steam reforming reactions. Analyses of the experimental catalyst measurements indicated the possibility of both endothermic and exothermic reaction stages and global reaction rates sufficient to enable the utilization of higher space velocities than those employed in our experiments. In a companion paper detailing Part 2 of this investigation, we present results for the engine dilution tolerance and brake engine efficiency impacts of the reforming levels achieved.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 1: Catalyst Performance

et al. 2018

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show abstract

Section: Introductionmentioning

confidence: 99%

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 2: Engine Performance

et al. 2018

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This is the second part of a two-part investigation of on-board catalytic fuel reforming to increase the brake efficiency of a multicylinder, stoichiometric spark-ignited (SI) engine. In Part 1 of the investigation, we analytically and experimentally characterized the energetics and kinetics of a candidate reforming catalyst over a range of reforming equivalence ratios and oxygen concentration conditions to identify the best conditions for efficient reforming. In the present part of our investigation, we studied an engine strategy that combined exhaust gas recirculation (EGR)–loop reforming with dilution limit extension of the combustion. In our experiments, we found that, under an engine operating condition of 2000 rpm and brake mean effective pressure (4 bar), catalytic EGR reforming made it possible to sustain stable combustion with a volumetric equivalent of 45%–55% EGR. Under this same operating condition with stoichiometric engine exhaust (and no reforming), we were only able to sustain stable combustion with EGR under 25%. These results indicate that multicylinder gasoline engine efficiency can be increased substantially with catalytic reforming combined with and higher EGR operation, resulting in a decrease of more than 8% in fuel consumption, compared to baseline operation.

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“…The high operating costs of hybrid-electric buses and improved battery economics have motivated a switch to full electrification of transit fleets. Simultaneously, forecasted increases in transit use are expected to result in a growth of the global market for battery electric transit buses from nearly 119,000 buses in 2016 to over 181,000 in 2026 ( 4 ). Implementing fully electrified buses on arterial routes enhances mobility while significantly improving energy productivity and reducing emissions.…”

mentioning

confidence: 99%

Impact of Time-Varying Passenger Loading on Conventional and Electrified Transit Bus Energy Consumption

Liu

Kotz

Salapaka

et al. 2019

Transportation Research Record: Journal of the Transportation R

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Transit bus passenger loading changes significantly over the course of a workday. Therefore, time-varying vehicle mass as a result of passenger load becomes an important factor in instantaneous energy consumption. Battery-powered electric transit buses have restricted range and longer “fueling” time compared with conventional diesel-powered buses; thus, it is critical to know how much energy they require. Our previous work has shown that instantaneous transit bus mass can be obtained by measuring the pressure in the vehicle’s airbag suspension system. This paper leverages this novel technique to determine the impact of time-varying mass on energy consumption. Sixty-five days of velocity and mass data were collected from in-use transit buses operating on routes in the Twin Cities, MN metropolitan area. The simulation tool Future Automotive Systems Technology Simulator was modified to allow both velocity and mass as time-dependent inputs. This tool was then used to model an electrified and conventional bus on the same routes and determine the energy use of each bus. Results showed that the kinetic intensity varied from 0.27 to 4.69 mi−1 and passenger loading ranged from 2 to 21 passengers. Simulation results showed that energy consumption for both buses increased with increasing vehicle mass. The simulation also indicated that passenger loading has a greater impact on energy consumption for conventional buses than for electric buses owing to the electric bus’s ability to recapture energy. This work shows that measuring and analyzing real-time passenger loading is advantageous for determining the energy used by electric and conventional diesel buses.

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Exploration of Dual Fuel Diesel Engine Operation with On-Board Fuel Reforming

Cited by 11 publications

References 30 publications

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 1: Catalyst Performance

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 1: Catalyst Performance

Catalytic Exhaust Gas Recirculation-Loop Reforming for High Efficiency in a Stoichiometric Spark-Ignited Engine through Thermochemical Recuperation and Dilution Limit Extension, Part 2: Engine Performance

Impact of Time-Varying Passenger Loading on Conventional and Electrified Transit Bus Energy Consumption

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