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Light Duty Truck Rear Axle Thermal Modeling

FCA-Mohammad Nahid
FCA US LLC-Joydip Saha, Sadek Rahman
  • Technical Paper
  • 2020-01-1388
To be published on 2020-04-14 by SAE International in United States
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more sophisticated vehicle thermal management systems to best utilize the waste heat and improve driveline efficiency. The final drive unit in light and heavy duty trucks usually consists of geared transmission and differential housed in a lubricated axle. The automotive rear axles is one of the major sources of power loss in the driveline due to gear friction, churning and bearing loss and have a significant effect on overall vehicle fuel economy. These losses vary significantly with the viscosity of the lubricant. Also the temperatures of the lubricant are critical to the overall axle performance in terms of power losses, fatigue life and wear. In this paper, a methodology for modeling thermal behavior of automotive rear axle with heat exchanger is presented to predict the axle lubricant temperature rise and study the effect of coolant temperature on the axle warm-up and efficiency for a typical EPA fuel economy driving cycle. Thermal axle consists of automotive rear axle with a heat…
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Parametric optimization of a Rankine cycle based waste heat recovery system for a 1.1 MW diesel-gen-set

Univ. of South Australia-Saiful Bari
University of South Australia-Wei Zhi Loh
  • Technical Paper
  • 2020-01-0890
To be published on 2020-04-14 by SAE International in United States
Due to the increasing fuel demand along with decreasing supply of petroleum, the need for an efficient IC engine is very important. Most IC engines now-a-days operate at a rather low efficiency, ranging from 20 to 40%, from a typical automobile engine to a diesel engine. This paper outlines the parametric study of a Rankine cycle (RC) based waste heat recovery system to improve the overall efficiency of a diesel-gen-set. WHR systems depend greatly on the exhaust temperature of the engine, whereby higher exhaust temperatures will result in a higher gain from the system. In this study, a 1.1MW diesel-gen-set was used to design a WHR system to generate additional power using RC. This is a large diesel engine and therefore, the exhaust temperature and flow rate are quite high to use water as the working fluid in WHR system. A computer code was written for the WHR system which was validated with experimental data. After the initial design of the WHR system, manufacturers were contacted to find out the availability of parts, and then,…
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Experimental evaluation and modeling of waste heat recovery in VECTO

Joint Research Centre-Stijn Broekaert, Theodoros Grigoratos, Georgios Fontaras
  • Technical Paper
  • 2020-01-1287
To be published on 2020-04-14 by SAE International in United States
Waste heat recovery based on an Organic Rankine Cycle is a technology proposed for the reduction of the fuel consumption of heavy-duty vehicles. This technology is currently not simulated by VECTO, the tool used in Europe to certify the fuel consumption and CO2 emissions of new heavy-duty vehicles. In this work, a class 5 lorry equipped with a prototype Organic Rankine Cycle system is tested on the chassis dyno during steady state and multiple transient driving cycles, with waste heat recovery enabled and disabled. The waste heat recovery system enabled a brake specific fuel consumption reduction of up to 6.5% during steady-state conditions, up to 3.1% during the World Harmonized Vehicle Cycle and up to 2.1% during the regional delivery cycle. A model of the vehicle was created in VECTO based on the experimental data. The waste heat recovery system was modelled by creating a fuel consumption map with the combined power output of the engine and the waste heat recovery system during the steady state experiments. The regional delivery cycle was simulated in VECTO…
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Designing regenerators of thermoacoustic engines for automotive waste heat recovery

Beihang University / KTH, CCGEx-Jianhua Zhou
KTH Royal Institute of Technology, CCGEx-Mikael Karlsson, Mats Abom
  • Technical Paper
  • 2020-01-0414
To be published on 2020-04-14 by SAE International in United States
Abstract: Extraction and utilization of automotive waste exhaust heat is an effective way to save fuel and protect the environment. One promising technology for this purpose is the thermoacoustic engine, where thermal energy is converted to mechanical energy in terms of high amplitude oscillations. The core component in a thermoacoustic engine is a regenerator where the process of energy conversion is mainly realized. This paper introduces a strategy for the design and optimization of this regenerator. It is then applied to typical light- and heavy-duty vehicles. Starting from 1-D linear thermoacoustic theory, the nonlinear effects (given by the high amplitude oscillations) are modelled as acoustic resistances and introduced into the basic linear equations to estimate the nonlinear dissipations in the regenerator. Then, a few dimensionless parameters are derived by normalizing these thermoacoustic equations. This yields a good overview of how different design parameters such as the geometrical dimensions, operating frequency, and thermal boundary conditions influence the performance of the regenerator. The results obtained in the current work show that the optimum designs for the regenerators…
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Experimental Investigations on a Novel Expansion Engine for Waste Heat Recovery

Mahle König Kommanditgesellschaft GmbH & Co KG-C. Bechter, T. Amann
TU Graz, Institute of Internal Combustion Engines and Thermo-M. Lang, S. Schurl, N. Bretterklieber
  • Technical Paper
  • 2019-32-0582
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Waste heat recovery in medium-power systems below 400 kW waste heat power asks for a novel expansion engine concept for water-based Rankine steam cycles. The aim is to combine the advantages of reciprocating piston engines and of turbines at reasonable costs. The so-called rotational wing-piston expander uses two pivoting shafts, each holding two wing-like pistons within one housing, that perform a cyclic movement relative to each other. Thus, four working chambers with varying volumes are shaped, each experiencing repetitive compression and expansion. This solution offers the possibility of sealing the lubricated gearbox against the steam-flooded section containing the working chambers with rotational seals.For the development of the expansion engine, starting with an initial approach for a functional prototype, experimental investigations are carried out. Motored tests are performed in order to scrutinize kinematics and mechanics. Tests with pressurized air for enhanced load on the components - without applying the corrosion and thermal stress of hot steam - are assessed. The structural problems at the piston mount during the test runs reveal improvement potential and lead to…
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Performance Analysis of Volumetric Expanders in Heavy-Duty Truck Waste Heat Recovery

KTH Royal Institute of Technology-Sandhya Thantla, Jens Fridh, Anders Christiansen Erlandsson
Scania CV AB-Jonas Aspfors
  • Technical Paper
  • 2019-01-2266
Published 2019-12-19 by SAE International in United States
With increasing demands to reduce fuel consumption and CO2 emissions, it is necessary to recover waste heat from modern Heavy Duty (HD) truck engines. Organic Rankine Cycle (ORC) has been acknowledged as one of the most effective systems for Waste Heat Recovery (WHR) due to its simplicity, reliability and improved overall efficiency. The expander and working fluid used in ORC WHR greatly impact the overall performance of an integrated engine and WHR system. This paper presents the effects of volumetric expanders on the ORC WHR system of a long haulage HD truck engine at a steady-state engine operating point chosen from a real-time road data. Performance of a long haulage HD truck engine is analyzed, based on the choice of three volumetric expanders for its WHR system, using their actual performance values. The expanders are: an oil-free open-drive scroll, a hermetic scroll and an axial piston expander with working fluids R123, R245fa and ethanol, respectively. Performance of the engine that accommodates the WHR system, with each expander and working fluid combination, is assessed based on…
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Prototype Design of a Small Scale Thermionic Energy Generator for Waste Heat Recovery in Hybrid Electric Vehicle

BSDU-Kantaprasad Kodihal, Ankur Sagar
Published 2019-10-11 by SAE International in United States
Sustainable energy solution for hybrid electric vehicles is an important area of research. Mobility and its ease is therefore being an essential component of development. Automotive technology is an area where methods are explored in recent times to provide sustainable solution for reduction of fuel consumption and carbon emissions by switching to hybrid technology and electric vehicles where regeneration of energy plays an important role. At present the research is focused on achieving methods of solid state conversion of heat into electricity but it is limited to thermoelectric methods which has lower conversion efficiency. A comparative analysis of the direct energy convertors shows that thermionic energy conversion stands better with a higher conversion efficiency. Very close and non-contact type of electrode spacing having electrical insulation provided with vacuum or inert gas environment is the basic requirement while designing any thermionic energy generator. Identifying these key research challenges, this article discusses the design of a prototype small scale thermionic generator. The paper hence explores a platform for conducting experimental research on solid state thermionic conversion, space…
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A Study and Mathematical Analysis of Thermionic Energy Conversion Materials Based on Their Solid State Emission Properties

BSDU-Kantaprasad Kodihal, Ankur Sagar
Published 2019-10-11 by SAE International in United States
The physical mechanism of direct energy conversion technology for space applications is well known for over a century. Whereas thermionic energy conversion is now being explored for automotive regeneration applications considering its high conversion efficiency. The thermionic emission used in space applications has operating temperatures >20000C which is much higher than available temperature at terrestrial automotive applications. Hence the key research interests are focused towards effective utilization of thermionic energy conversion for automotive waste heat recovery at considerably lower temperatures i.e. <10000C. This strongly needs a selection of suitable materials in thermionic convertor. This work shows a comprehensive study on materials and their work function for thermionic emission at relatively lower temperature. The selection of different emitter materials is based on simulation applying Richardson Dushman equation and child’s law at operating temperature ranges. The paper concludes with a comparative analysis of high and low work function materials showing their behavior of thermionic emission at specified temperature.
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Chip Converts Wasted Heat to Usable Energy

  • Magazine Article
  • TBMG-35259
Published 2019-10-01 by Tech Briefs Media Group in United States

Car engines, laptop computers, cellphones, and refrigerators all heat up with overuse. That heat can be captured and turned into energy using a method that produces electricity from heat. The technology uses a silicon chip, also known as a “device,” that converts more thermal radiation into electricity. This could lead to devices such as laptop computers and cellphones with much longer battery life and solar panels that are much more efficient at converting radiant heat to energy.

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

Dolphin N2 Ltd-Nicholas Owen
Ricardo UK Ltd-Rhys Pickett, Andrew Atkins
Published 2019-09-09 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 in thermal efficiency over conventional Otto and Diesel cycle engines. In a split cycle engine, the compression and combustion strokes are performed in different cylinders. Intensive cooling of the compression stroke by the injection of liquid nitrogen directly into the chamber enables the recovery of waste heat from the exhaust between the compression and combustion cylinders. Brake efficiencies of over 50% have been reported without compression cooling, rising to 60% where the compression stroke is cooled by the injection of liquid nitrogen. The technology targets the heavy duty, long-haul sector where electrification is ineffective.In this paper, results from an experimental program conducted on a single cylinder research engine, representing the combustor cylinder of a recuperated split cycle engine are reported. The effect of fuel injection timing, valve timing and injection pressure were studied at 1200rpm at a range of loads. Experiments using oxygen depleted air to represent the effect of the injection of liquid nitrogen in…
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