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Electric Vehicle Thermal Management System For Hot Climate Regions

Pranav Vikas India Private Limited-Tarun Rana, Yuji Yamamoto
  • Technical Paper
  • 2019-28-2507
To be published on 2019-11-21 by SAE International in United States
ELECTRIC VEHICLE THERMAL MANAGEMENT SYSTEM FOR HOT CLIMATE REGIONS Rana Tarun*, Yamamoto Yuji, Kumar Ritesh, Bhagatkar Shubhada Pranav Vikas India Private Limited, India Key Words Electric Vehicles (EV); Battery Thermal Management System (BTMS); COP; Electric Vehicle Thermal Management System (EVTMS); BTMS and HVAC System Integration; Thermal System Performance Comparison; Active Liquid Cooling; EV Battery Cooling Research and/or Engineering Questions/Objective Electric Vehicles is the need of time to limit global warming and it is in application at a wide scale in colder or mild climate regions where ambient temperature is limited to mild or moderate level. Its application (Heat pump, CO2) is constrained to cold climates only due to securing better COP for heating function, sacrificing cooling COP of the existing system when operated in Hot Climate Regions, thus limiting its application to nearly half of the automotive user-base. This study is aimed to develop a new Electric Vehicle Thermal Management System (EVTMS) limited to active liquid cooling for application of Electric Vehicle in Hot Climate Regions with higher system COP targets when compared to existing…

Prototype design of a small scale thermionic energy generator for waste heat recovery in hybrid electric vehicle.

BSDU-Kantaprasad Kodihal, Ankur Sagar
  • Technical Paper
  • 2019-28-0027
To be published on 2019-10-11 by SAE International in United States
The sustainability of energy generation is primarily based on the effectiveness of the methods used for minimizing the wastes and optimum utilization of available energy resources. 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 emission 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 its limited to thermoelectric 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 a design of a prototype small scale thermionic generator. The paper hence explores…

A Study and mathematical analysis of thermionic energy conversion materials based on their solid state emission properties.

BSDU-Kantaprasad Kodihal, Ankur Sagar
  • Technical Paper
  • 2019-28-0084
To be published on 2019-10-11 by SAE International in United States
The physical mechanism of direct energy conversion technology for space applications is well known 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 >2000o C 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. <1000oC. 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 behaviour of thermionic emission at specified temperature. Keywords: thermionic emission; work function; thermionic equation; space charge effect.

How to Improve SI Engine Performances by Means of Supercritical Water Injection

University of Basilicata – Potenza 85100-Antonio Cantiani, Annarita Viggiano, Vinicio Magi
  • Technical Paper
  • 2019-24-0235
To be published on 2019-10-07 by SAE International in United States
The efficiency of ICEs is strongly affected by the heat losses of exhaust gases and engine cooling system, which account for about 60% of the heat released by combustion. Several technologies were developed to recover waste heat in ICEs, from turbochargers to ORCs, Stirling cycles and piezoelectric generation. A promising approach is to transfer the waste heat to a fluid, like water, and inject it into the combustion chamber. In such a way, the recovered energy is partially converted into mechanical work, by improving both engine efficiency and performance. In this work, the engine benefits obtained by using supercritical water as the vector to recover heat losses are analysed. Water has been chosen since it has a relatively high heat capacity and can be extracted directly from exhaust gases. A quasi-dimensional model has been implemented to simulate the ICE work cycle. Specifically, in this paper a spark ignition ICE, four-stroke with port fuel injection (PFI) has been considered. The model accounts for gas species properties (Janaf tables and CoolProp libraries) and includes valves opening/closing laws,…

Thermal Efficiency Comparison of Different Injector Constellations in a CI Engine

King Abdullah Univ. of Science & Tech.-Gustav Nyrenstedt, Hao Shi, Bengt Johansson
New Ace Inst Co Ltd-Kazumasa Watanabe, Kenji Enya, Noboru Uchida
  • Technical Paper
  • 2019-24-0172
To be published on 2019-09-09 by SAE International in United States
Towards the goal of high efficiency, heat losses through the cylinder walls need to be reduced for heavy-duty CI engines. This study proposes the use of multiple injectors to overcome this issue. Comparisons of one, two and three injectors’ utilizations are performed with optical and metal engines as well as CFD studies. Furthermore, a flat bowl is compared to the standard bowl in terms of performance and heat losses. It has earlier been proven that the distance from injector to the wall is significant in terms of heat loss reduction. A flat bowl increases this distance, and is thus, together with a smaller surface area, expected to reduce heat losses. Performance measures from the metal experiments proved the benefits of multiple injectors in terms of heat loss reduction and efficiency gain. The flat bowl further reduced the heat losses without adventuring the mixing capabilities. From the optical experiments, the spray and flame movements were evaluated. The importance of flame/wall interaction for heat losses was confirmed with optimized spray angles studied further in RANS CFD simulations.…

One-Dimensional Modeling of a Thermochemical Recuperation Scheme for Improving Spark-Ignition Range Extender Engine Efficiency

Univ of Minnesota-Twin Cities-William F. Northrop, Darrick Zarling
  • Technical Paper
  • 2019-24-0066
To be published on 2019-09-09 by SAE International in United States
Vehicle electrification has accelerated as global fuel efficiency standards have become more stringent and battery costs have decreased. Although full electrification, i.e.; battery electric vehicles, may be appropriate for some light-duty vehicle applications, many vehicles will still require an engine to overcome range limitations. Range extender (REx) engine generators can be used to charge vehicle batteries as needed to meet driver demands. One advantage of REx engines is that they do not have a direct mechanical connection to the wheels and can frequently within the most efficient speed and load ranges. Therefore, REx engines provide an opportunity to implement advanced engine technologies that are more difficult to apply in conventional engine-powered vehicles. Thermochemical recuperation (TCR) schemes use exhaust waste heat to catalytically convert a portion of the fuel into a gas that has increased heating value. TCR schemes are ideal for REx architectures because they yield the most benefit at relatively high engine load and because they do not respond well to rapid transients. This paper explores a TCR scheme for a 2-cylinder BMW spark-ignition…

A Mild Hybrid SIDI Turbo Passenger Car Engine with Rankine Waste Heat Recovery

Volvo Car Corporation-Fredrik B. Ekström, Ola Rolandson, Soren Eriksson, Christer Odenmarck, Mattias Svensson, Andreas Eriksson, Hans Olsen
  • Technical Paper
  • 2019-24-0194
To be published on 2019-09-09 by SAE International in United States
In the strive for more fuel-efficient vehicles all possible measures are considered to increase the efficiency of the combustion engine. 48V mild hybrid technology is one such measure; SIDI (Spark Ignited Direct Injection) engines with Miller technology another, while recovering energy from the engine waste heat (WHR) is yet an option to increase fuel conversion efficiency. Here, for the first time, we will publish the results from an advanced engineering project at Volvo Cars including all these components. We have successfully built an ethanol based Rankine system around a 4-cylinder, 2.0 litre SIDI-engine, including 48V mild hybrid technology. The Rankine system uses the engine exhaust as heat source, while the expansion of the ethanol steam occurs in an axial piston expander coupled both electrically to the hybrid system and mechanically to the engine crankshaft. This dual power output from the steam expander we see is of particular importance for a passenger car with transient driving style, giving the opportunity to recover more energy from the waste heat by overcoming the slow response from the steam…

Thin-Film System Converts Heat from Electronics into Energy

  • Magazine Article
  • TBMG-34758
Published 2019-07-01 by Tech Briefs Media Group in United States

Nearly 70 percent of the energy produced in the United States each year is wasted as heat. Much of that heat is less than 100 °C and emanates from things like computers, cars, or large industrial processes. A thin-film system was developed that can be applied to sources of waste heat like these to produce energy at levels unprecedented for this kind of technology.


Generating Electrical Power from Waste Heat

  • Magazine Article
  • TBMG-34611
Published 2019-06-01 by Tech Briefs Media Group in United States

Directly converting electrical power to heat is easy; however, converting heat into electrical power is not as easy. To address this issue, a tiny silicon-based device was developed that can harness what was previously called waste heat and turn it into DC power. The device could be used as a compact infrared power supply that could replace radioisotope thermoelectric generators (RTGs) that are used for such tasks as powering sensors for space missions that don’t get enough direct sunlight to power solar panels. The device is made of common and abundant materials such as aluminum, silicon, and silicon dioxide — or glass — combined in uncommon ways.


The Thermodynamic Design, Analysis and Test of Cummins’ Supertruck 2 50% Brake Thermal Efficiency Engine System

Cummins Inc.-Daniel Mohr, Timothy Shipp, Xueting Lu
Published 2019-04-02 by SAE International in United States
Current production heavy duty diesel engines have a brake thermal efficiency (BTE) between 43-46% [1]. In partnership with the United States Department of Energy (DOE) as part of the Supertruck 2 program, Cummins has undertaken a research program to develop a new heavy-duty diesel engine designed to deliver greater than 50% BTE without the use of waste heat recovery. A system level optimization focused on: increased compression ratio, higher injection rate, carefully matched highly efficient turbocharging, variable lube oil pump, variable cooling components, and low restriction after treatment designed to deliver 50% BTE at a target development point. This work will also illustrate the system level planning and understanding of interactions required to allow that same 50% BTE heavy duty diesel engine to be integrated with a waste heat recovery (WHR) system to deliver system level efficiency of 55% BTE at a single point. In addition to a test bench demonstration, the described system is also planned to be demonstrated at a vehicle system level. This paper summarizes the process and results of the 50%…
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