Thermodynamic Analysis of a Five-Stroke Engine with Heat Transfer and Mass Loss

Stuart, Kurt; Yan, Terry; Mathias, James A.

doi:10.4271/2017-01-0633

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…der five-stroke e expansion cylin 5 -intake mani valves, 8 -exh of the five-s m working on t in [25,26]. G ne raises a l over the w on various m ngine [27][28][29][30][31] area of a ne e paper [13] ency of the pro …”

Section: Introductionmentioning

confidence: 99%

Various aspects of research of the SI engine with an additional expansion process

Noga

2017

MATEC Web Conf.

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Abstract. The paper presents an analysis of the results of the both experimental results and theoretical works on the SI engine with additional expansion of exhaust gases, also known as five-stroke engine. The engine like this was constructed at Cracow University of Technology as a retrofitted in-line four cylinder engine in which outer cylinders (1st and 4th) work as fired cylinders and inner cylinders (2nd and 3rd) work as volume for the additional expansion. The aim of development of such an engine is to gain higher energy recovery ratio of the combusted fuel through the second expansion of exhaust in a separate cylinder. The operating parameters of the engine in various versions were analyzed: as naturally aspirated, supercharged using a turbocharger with a waste-gate valve and a turbocharger with variable nozzle turbine. Selected results of the indicating measurements of the engine with special emphasis on the indicated thermal efficiency were presented. The results pointed out the directions of further optimization of the engine. These results are all the more important, because according to the author's knowledge, the research on the real object of this type are carried out in only one science center in the world besides Cracow University of Technology.

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Section: Introductionmentioning

confidence: 99%

Various aspects of research of the SI engine with an additional expansion process

Noga

2017

MATEC Web Conf.

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Downsized Boosted Dilute Combustion, Exhaust Compounded (DBDC+EC) Experimental Engine Design, Thermodynamic Model Comparison, and Performance Potential Predictions

Andruskiewicz¹,

Durrett²,

Najt³

2021

SAE Int. J. Adv. & Curr. Prac. in Mobility

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<div class="section abstract"><div class="htmlview paragraph">An experimental piston compounded engine was designed with guidance from thermodynamic modeling, then was built and tested to compare the model predictions to measured results. The piston-compounded concept has shown great potential for improvements in efficiency over current state-of-the-art light-duty engines through the use of an efficient second expansion process to more fully recover energy still present in the exhaust gasses, and was further developed into the Downsized Boosted Dilute Combustion, Exhaust Compounded (DBDC+EC) engine presented here. This paper documents some of the more unique design elements of this engine as well as a performance comparison between test data and modeling expectations. Ultimately, an experimental stoichiometric spark-ignited piston compounded engine was designed, five blocks were built, and collectively they were run for thousands of hours. The experimental engines achieved a minimum of 222 g/kW-hr BSFC with a wide region of operation under 250 g/kW-hr, and the performance matched predictions from a thermodynamic model that reflected the as-built hardware. Predictions for a 2nd generation DBDC+EC engine result in a 10% fuel economy improvement over a similar downsized boosted stoichiometric SI engine, with an additional 9% improvement for lean operation at low load. These result in minimum BSFCs of 212 and 206 g/kW-hr for the stoichiometric and lean DBD+EC Gen 2 engines respectively.</div></div>

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Experimental Comparison of Low-Load Piston Compounding Deactivation for the DBDC+EC Engine Architecture

Andruskiewicz¹,

Durrett²,

Najt³

2021

SAE Int. J. Adv. & Curr. Prac. in Mobility

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<div class="section abstract"><div class="htmlview paragraph">An experimental piston compounded engine was designed with guidance from thermodynamic modeling, then was built and tested to compare the model predictions to measured results. This Downsized Boosted Dilute Combustion, Exhaust Compounded (DBDC+EC) engine concept has shown great potential for improvements in efficiency at high loads through extended second expansion process, but suffered from excessive expander cylinder pumping and low exhaust temperatures at low loads. Four expander operating strategies were experimentally tested and simulated at a range of engine speeds and loads to determine the most efficient method to deactivate the piston compounding at low loads. The most effective method involved deactivating all the expander valves and operating it as an air-spring while diverting power cylinder exhaust gasses through a separate bypass port. While this method requires some unique hardware development to enable on-the-fly actuation, it offers 15% to 22% improvements in low-load BSFC over the active expander method while improving exhaust temperatures by 100° to 150°C.</div></div>

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Thermodynamic Analysis of a Five-Stroke Engine with Heat Transfer and Mass Loss

Cited by 3 publications

References 7 publications

Various aspects of research of the SI engine with an additional expansion process

Various aspects of research of the SI engine with an additional expansion process

Downsized Boosted Dilute Combustion, Exhaust Compounded (DBDC+EC) Experimental Engine Design, Thermodynamic Model Comparison, and Performance Potential Predictions

Experimental Comparison of Low-Load Piston Compounding Deactivation for the DBDC+EC Engine Architecture

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