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A Novel Option for Direct Waste Heat Recovery From Exhaust Gases of Internal Combustion Engines

Universita degli Studi dell Aquila-Davide Di Battista, Roberto Cipollone PhD, Roberto Carapellucci PhD
  • Technical Paper
  • 2020-37-0004
To be published on 2020-06-23 by SAE International in United States
Among the different opportunities to save fuel and reduce Co2 emissions from internal combustion engines, great attention has been done on the waste heat recovery: the energy wasted is, in fact, almost two thirds of the energy input and even a partial recovery into mechanical energy is really promising . Usually, thermal energy recovery has been referred to a direct heat recovery (furtherly expanding the gases expelled by the engine thanks to their high pressure and temperature) or an indirect one (using the thermal energy of the exhaust gases – or of any other thermal streams discharged into the atmosphere – as upper source of a conversion power unit which favour a thermodynamic cycle of a working fluid ). Limiting the attention to the exhaust gases, a novel opportunity can be represented by directly exploiting the residual pressure and temperature of the flue gases through an Inverted Brayton cycle (IBC), in which the gases are expanded at a pressure below the environmental one, cooled down and then recompressed to the environmental pressure. Considering the thermodynamic…
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A Power Split Hybrid Propulsion System for Vehicles with Gearbox

Istituto Motori CNR-Luigi De Simio, Michele Gambino, Sabato Iannaccone
  • Technical Paper
  • 2020-37-0014
To be published on 2020-06-23 by SAE International in United States
New internal combustion engines (ICE) are characterised by increasing maximum efficiency, thanks to the adoption of strategies like Atkinson cycle, downsizing, cylinder deactivation, waste heat recovery and so on. However, the best performance is confined to a limited portion of the engine map. Moreover, electric driving in urban areas is an increasingly pressing request, but battery electric vehicles use cannot be easily widespread due to limited vehicle autonomy and recharging issues. Therefore, in order to reduce ICE vehicle fuel consumption, by decoupling the ICE running from road load, as well as permit energy recovery and electric driving, hybrid propulsion systems are under development. This paper analyses a new patent solution for power split hybrid propulsion system with gearbox. The system comprises an auxiliary power unit, adapted to store and/or release energy, and a planetary gear set which is interposed between the ICE and the gearbox. The system is characterized by a further device coupled with the ICE to modulate the resistance torque, in order to use the auxiliary power unit also for regenerative braking. The…
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Universal Electric Vehicle Thermal Management System

Electric Vehicle Thermal Management-Tarun Rana, Yuji Yamamoto
  • Technical Paper
  • 2020-28-0002
To be published on 2020-04-30 by SAE International in United States
Universal Electric Vehicle Thermal Management System describes a thermal system architecture that delivers efficient year round thermal performance for electric vehicles. Proposed system takes care for cabin thermal comfort, battery thermal comfort. A benchmark study for thermal management system for electric vehicle shows that there is no efficient thermal system available that can be applicable to year round requirements of different geographical regions. Proposed system delivers less refrigerant pressure drop throughout the system and waste heat recovery from high thermal potential of refrigerant on discharge side of compressor to cabin heater using a water condenser. A single compressor and pump takes care for circulating refrigerant and coolant respectively for entire thermal system. An extensive simulation and testing validation for the proposed system is carried out to prove the efficient functionality of the proposed system. Waste energy recovery is the key to improve thermal system performance and same has been successfully validated for the proposed system with different stage of testing. Different simulations were carried out using 1-D simulation tool and parallel validation is done system…
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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
In this study, a 1.1 MW diesel-gen-set is used to design a Waste Heat Recovery (WHR) system to generate additional power using Rankine cycle (RC). A computer code is written in commercial Engineering Equation Solver (EES) software to solve equations of overall energy and mass balance, heat transfer, evaporation, condensation, frictional and heat losses for heat exchangers, turbine, pumps, cooling tower and connecting pipes connecting different components. After initial design of the WHR system, manufacturers are contacted to find out the availability of parts, and then, accordingly the design is changed. There are several heat exchangers required to heat the water from liquid to superheated steam and then, it is passed to the turbine. Then, after the expansion in the turbine, it is passed to the condenser to condense the steam to water. Optimization is done on the heat exchangers, focusing on the tube length and diameter. The tube length is changed in accordance to the availability on the market, where it comes in 2 m length. At the rated power of the gen-set, with…
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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 transient driving cycles, with the waste heat recovery enabled and disabled. The waste heat recovery system enabled a brake specific fuel consumption reduction of 3.1% over the World Harmonized Vehicle Cycle, 2.5% during the official EU Regional Delivery Cycle, and up to 6.5% at certain engine operating points during the fuel consumption mapping cycle. A model of the vehicle was created in VECTO based on the experimental data. The fuel consumption map of the engine with and without the Organic Rankine Cycle was derived from the steady-state experiments. Multiple modelling approaches to simulate the vehicle fuel consumption with waste heat recovery were…
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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
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 travelling-wave thermoacoustic engine is its regenerator where the process of energy conversion is mainly realized. This paper introduces a strategy for the design of the regenerator for applications in 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 temperature, and thermal boundary conditions influence the performance of the regenerator. For the application of automotive waste heat recovery, the thermal properties of the actual exhaust gas are accepted to…

Performance Evaluation of a Heavy-Duty Diesel Truck Retrofitted with Waste Heat Recovery and Hybrid Electric Systems

SAE International Journal of Alternative Powertrains

Universita degli Studi Niccolo Cusano, Italy-Manfredi Villani, Simone Lombardi, Laura Tribioli
  • Journal Article
  • 08-09-01-0004
Published 2020-03-11 by SAE International in United States
The interest of long-hauling companies about the conversion of their fleets into low-emission and fuel-efficient vehicles is growing, and retrofitting options may represent a suitable solution. Powertrain hybridization and waste heat recovery are considered among the most promising methods to further improve the fuel economy of road vehicles powered by internal combustion engines. In this article, not only the effect of retrofitting a heavy-duty truck with an electrification-oriented ORC unit or with a series hybrid system is investigated, but also the possibility of implementing both at the same time. The conventional vehicle is powered by a heavy-duty 12.6 liters diesel engine. It is shown that, despite such a large engine has high potential for waste heat recovery, on the other hand it represents a very challenging constraint when designing a hybrid retrofitting. Four powertrain options are considered: conventional vehicle (engine-only powered), waste heat recovery retrofit, hybrid retrofit, waste heat recovery+hybrid retrofit. For the hybrid powertrains, the optimal control strategy is analyzed and used as a starting point to develop an online implementable rule-based control strategy.…
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Waste Heat Recovery System Thermal Management

Cooling Systems Standards Committee
  • Ground Vehicle Standard
  • J3173_202002
  • Current
Published 2020-02-24 by SAE International in United States
Waste heat recovery (WHR) systems are used in vehicles and machines powered by internal combustion (IC) engines to capture unused/waste heat and utilize it thereby reducing fuel consumption and emissions by improving efficiency. This information report is a survey of the waste heat recovery methods that include the use of heat exchangers.
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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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