DOCSLIB.ORG

Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts Dissertation by Vijai Shankar Bhavani Shankar In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia © November, 2019 Vijai Shankar Bhavani Shankar All rights reserved EXAMINATION COMMITTEE PAGE This dissertation of Vijai Shankar Bhavani Shankar is approved by the examination committee. Committee Chairperson: Dr. Mani Sarathy Committee Members: Dr. Bengt Johansson, Dr. Himanshu Mishra, Dr. Jamie Turner 2 ABSTRACT Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts Vijai Shankar Bhavani Shankar The efficiency of an internal combustion (IC) engine is governed by the thermodynamic cycle underpinning its operation. The thermodynamic efficiency of these devices is primarily determined by the temperature gradient created during the compression process. The final conversion efficiency also known as brake thermal efficiency (BTE) of IC engines, however, also depend on other processes associated with its operation. BTE is a product of the combustion, thermodynamic, gas-exchange, and mechanical efficiencies. The improvement of BTE through maximation of any one of the four efficiencies is reduced by its implication of the other three. Split-cycle engine provides an alternative method of improving the engine efficiency through over- expansion of combustion gases by transferring it to a cylinder of greater volume. The operation of split-cycle engines is based on either the Brayton or the Atkinson Cycles. Atkinson Cycle has been demonstrated in IC engines without the split-cycle architecture but is limited by the reduced energy density. Double Compression Expansion Engine (DCEE) provides a method of accomplishing the Atkinson Cycle without the constraints faced in conventional engine architectures. DCEE splits the compression and expansion processes in a vertical manner that enables the use of larger cylinder volumes for over-expansion as well as first-stage compression without much friction penalties. 3 The present thesis explores the thermodynamic cycle of this novel engine architecture using well- validated 1-dimensional engine models solving for gas-exchange, real gas properties, and heat transfer provided in the GT-Power software tool. The effect of compression ratio, rate of heat addition, sensitivity to design and modeling parameters was assessed and contrasted against conventional engine architecture. The synergies of combining low-temperature combustion (LTC) concepts with DCEE was investigated using simulation and experimental data. DCEE relaxes many constraints placed the operation of an engine in Homogenous Charge Compression Ignition (HCCI) mode. The limitations of adopting Partially Premixed Combustion (PPC) concept is also alleviated by the DCEE concept. BTE improvement of above 10% points is achievable through the DCEE concept along with possibility to achieve very low emissions through use of LTC concepts and new after-treatment methods uniquely available to the DCEE. 4 ACKNOWLEDGEMENTS “Standing on the shoulders of giants” – Bernard of Chartres The work while credited to this author is really the result of the cooperation of many souls who have overwhelmed me with their kindness. Prof. Bengt Johansson, Prof. Mani Sarathy, and Mr. Arne Andersson played a pivotal in shaping my thought process and attitude towards research. They have been terrific role models for a young researcher with their dedication towards the science of combustion and their relentless pursuit of excellence. I am very fortunate to be blessed with the endless love and adoration of my parents, Mr. Bhavani Shankar and Mrs. Lakshmi Shankar who have supported and provided for me. I hope their best efforts at molding me into a good human being is reflected by my actions in professional and personal life. I would also like to thank my grandmother, Mrs. Kalyani who has exemplified love, sacrifice, and humility before God. I am indebted to the late King Abdullah for his vision and perseverance of creating an extraordinary institution that has nurtured and developed me. I am forever grateful to the great man and his memory. I am thankful for the excellent faculty of the Clean Combustion Research Center. Prof. Robert Dibble has taken the role of the wise sage in my life. The width and depth of his experience, his ability to communicate, and hold an audience captive, his endless curiosity for science and technology. I consider his a life to cherish and emulate. I am in awe of Prof. William Roberts and Prof. Suk Ho Chung for their audacity to envision and materialize such a top center for combustion research. 5 I like to send my warmest hugs to – Major. Puli Pandian, Captain. Arun, Mr. Suraj Tiwari, Mr. Ahkilesh Krishnan, Mr. Yashwanth Narayanan, Mr. Raghavendran Pala, and Dr. Ehson Fawad Nasir for being the most magnificent buds. Finally, I like to thank my peers and friends at CCRC, especially Dr. Samah Mohamed, Dr. Nour Elsagan, Dr. Adamu Alfazazi, Dr. Ahfaz Ahmed, Dr. Eshan Singh, Dr. Mariam El Rachidi, Prof. Zhandong Wang, Mr. Ariff Magdoom, Dr. Yang Li, and Ms. Can Shao for being inspirational with your outstanding research and for extending your friendship to me. 6 TABLE OF CONTENTS EXAMINATION COMMITTEE PAGE………………………………………. 2 ABSTRACT……………………………………………………………………… 3 ACKNOWLEDGEMENTS……………………………………………………... 5 TABLE OF CONTENTS………………………………………………………... 7 LIST OF FIGURES……………………………………………………………… 9 LIST OF TABLES……………………………………………………………… 11 1 Introduction .............................................................................................................................. 13 1.1 Objectives and Limitations ................................................................................................. 14 1.1 Thesis Contribution ............................................................................................................. 14 1.2 Outline................................................................................................................................. 16 2 Literature .................................................................................................................................. 18 2.1 Evolution of Class 8 Vehicle Engine .................................................................................. 19 2.2 SuperTruck .......................................................................................................................... 20 2.3 Split-Cycle Engines ............................................................................................................ 22 3 Thermodynamic Cycles ........................................................................................................... 26 3.1 Otto and Diesel Cycles........................................................................................................ 26 3.2 Over-Expanded Cycles ....................................................................................................... 29 3.3 Real Cycles - Heat Transfer, Gas-Exchange, and Friction ................................................. 33 3.3.1 Quantifying Losses in Real Cycles. ............................................................................. 35 3.4 Conclusions ......................................................................................................................... 54 4 Double Piston Compression Expansion Engine .................................................................... 55 4.1 Implementing the Atkinson Cycle ...................................................................................... 55 4.2 Efficiencies and Losses in DCEE ....................................................................................... 59 4.2.1 Engine Model ............................................................................................................... 59 4.2.2 Results .......................................................................................................................... 60 4.3 Conclusions ......................................................................................................................... 66 5 Optimum Heat Addition Process for DCEE ......................................................................... 68 5.1 Influence of Heat Addition Process on Efficiency and Losses ........................................... 68 5.1.1 Wiebe Function ............................................................................................................ 69 7 5.1.2 Results .......................................................................................................................... 72 5.2 Conclusions ......................................................................................................................... 83 6 Parametric Study and Optimization of DCEE Configuration ............................................ 84 6.1 Sensitivity of System Efficiency to Heat Transfer Losses .................................................. 84 6.1.1 Influence of Heat Transfer Coefficient Scaling Factor ................................................ 84 6.1.2 Influence of Charge Air Cooling Temperature ............................................................ 87 6.2 Compressor and Expander Geometry ................................................................................. 95 6.2.1 Compressor Compression Ratio .................................................................................
Load more

Recommended publications
  • No. 350,446. Patented .Oct. 5, 1886
    (No Model.) 3 Sheets-Sheet 1. J. RICHARDS. ‘ ' COMPOUND STEAM ENGINE. No. 350,446. Patented .Oct. 5, 1886. : ' gvweml'o'c I (No Model.) 3 Sheets-Sheet 2. J. RICHARDS. COMPOUND STEAM ENGINE. No. 350,446. Patented 00's. 5, 1886.> I _ _._.|_ 6" ______I___l l _ _ _ _ __ |t____ ___ T ____|"f __—__ ' l |_ _ _ _ _ _ _ _ _'_ _ _ _ _ _ _ __ wand-50% ' gvwami'oz -' @Qf’d _ 33913 ' GMMW6%4 (No Model.) 3 Sheets-Sheet 3. J. RICHARDS. COMPOUND STEAM ENGINE. No. 350,446. - ' Patented Oct. 5, 1886. 2774/l/ _ L 1 M F37. a. / WA TE/i’ q/Vtlmeooao WM (5. MW N. PETERS. Pholo-Lilhngmphw. Wnshmglnh. Dv C. NI-TED STATES PATENT OFFICE. ’ JOHN RICHARDS, OF SAN FRANCISCO, ‘CALIFORNIA. COMPOUND STEAM-ENGINE. SPECIFICATION forming part of Letters Patent No. 350,446, dated October 5, 1886, ' Application ?led May 13, 1866. Serial No. 202,042. (No model.) To all whom. it may concern: right angles to the sectionslof Fig. 2, and trans Be it known that I, J OHN RICHARDS, a citi verse to the axial line of the shaft, and Fig. 4 zen of the United States, residing at San Fran is a partial top plan view. 55 cisco, in the county of San Francisco and State Like letters of reference designate like parts of California, have invented certain new and throughout the several views. useful Improvements in Compound Steam-.En A represents the main frame or hollow col gines; and I do declare the following to be a umn, which supports thereon the cylinder B, ' full, clear, and exact description of theinven and which is itself supported upon the base 0, tion, such as will enable others skilled in the ‘ said base serving also as a condenser, as will IO art to which it appertains to make and use be hereinafter explained.
    [Show full text]
  • Triple-Expansion Steam Engine
    WaterWords News from the Waterworks Museum - Hereford Winter 2015/16 120th Anniversary of the triple-expansion engine The Museum was delighted to receive as its guests of honour Sir Colin and Lady Shepherd on the occasion of the 120th anniversary of our gentle giant. Sir Colin made an incredibly support- ive and inspiring speech, followed by unveiling a commemorative engraved plaque as a permanent reminder of the historic day. The triple-expansion steam engine had been officially opened and set in motion in 1895 and by happy chance the anniver- sary was celebrated on the exact same day, 25th October. In an echo of the origi- nal event, Sir Colin ordered the engine to start and, thanks to detailed work a few minutes prior by Museum volunteer engi- neers, it did exactly as commanded! We were equally pleased to have present for this special occasion Candia Compton, representing the Southall Trust, accompa- nied by her husband Chris. Full report p4. Sir Colin and Lady Shepherd greeted by Museum Chairman Noel Meeke Grant awarded by the Record visitors Half-term fun day West Midlands Museum Only once in recent years, 2013, Development Group has the number of visitors to the Museum exceeded 5000. That year The Waterworks Museum will be the the figure reached 5079. national centre for the bicentenary celebrations marking the first patent The Trustees are pleased to report that awarded for a hot-air engine. In 1816 visitor numbers for 2015 have exceed- ed 5400, an increase over last year of the Rev Robert Stirling, a clergyman 13 per cent.
    [Show full text]
  • Benchmarking a 2018 Toyota Camry 2.5L Atkinson Cycle Engine With
    Downloaded from SAE International by John Kargul, Thursday, April 04, 2019 2019-01-0249 Published 02 Apr 2019 Benchmarking a 2018 Toyota Camry 2.5-Liter INTERNATIONAL. Atkinson Cycle Engine with Cooled-EGR John Kargul, Mark Stuhldreher, Daniel Barba, Charles Schenk, Stanislav Bohac, Joseph McDonald, and Paul Dekraker US Environmental Protection Agency Josh Alden Southwest Research Institute Citation: Kargul, J., Stuhldreher, M., Barba, D., Schenk, C. et al., “Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR,” SAE Technical Paper 2019-01-0249, 2019, doi:10.4271/2019-01-0249. Abstract idle, low, medium, and high load engine operation. Motoring s part of the U.S. Environmental Protection Agency’s torque, wide open throttle (WOT) torque and fuel consumption (EPA’s) continuing assessment of advanced light-duty are measured during transient operation using both EPA Tier Aautomotive technologies in support of regulatory and 2 and Tier 3 test fuels. Te design and performance of this 2018 compliance programs, a 2018 Toyota Camry A25A-FKS 2.5-liter engine is described and compared to Toyota’s published 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine data and to EPA’s previous projections of the efciency of an with cooled exhaust gas recirculation (cEGR) was bench- Atkinson Cycle engine with cEGR. The Brake Thermal marked. Te engine was tested on an engine dynamometer Efciency (BTE) map for the Toyota A25A-FKS engine shows with and without its 8-speed automatic transmission, and with a peak efciency near 40 percent, which is the highest value of the engine wiring harness tethered to a complete vehicle parked any publicly available map for a non-hybrid production gasoline outside of the test cell.
    [Show full text]
  • Hybrid Electric Vehicles: a Review of Existing Configurations and Thermodynamic Cycles
    Review Hybrid Electric Vehicles: A Review of Existing Configurations and Thermodynamic Cycles Rogelio León , Christian Montaleza , José Luis Maldonado , Marcos Tostado-Véliz * and Francisco Jurado Department of Electrical Engineering, University of Jaén, EPS Linares, 23700 Jaén, Spain; [email protected] (R.L.); [email protected] (C.M.); [email protected] (J.L.M.); [email protected] (F.J.) * Correspondence: [email protected]; Tel.: +34-953-648580 Abstract: The mobility industry has experienced a fast evolution towards electric-based transport in recent years. Recently, hybrid electric vehicles, which combine electric and conventional combustion systems, have become the most popular alternative by far. This is due to longer autonomy and more extended refueling networks in comparison with the recharging points system, which is still quite limited in some countries. This paper aims to conduct a literature review on thermodynamic models of heat engines used in hybrid electric vehicles and their respective configurations for series, parallel and mixed powertrain. It will discuss the most important models of thermal energy in combustion engines such as the Otto, Atkinson and Miller cycles which are widely used in commercial hybrid electric vehicle models. In short, this work aims at serving as an illustrative but descriptive document, which may be valuable for multiple research and academic purposes. Keywords: hybrid electric vehicle; ignition engines; thermodynamic models; autonomy; hybrid configuration series-parallel-mixed; hybridization; micro-hybrid; mild-hybrid; full-hybrid Citation: León, R.; Montaleza, C.; Maldonado, J.L.; Tostado-Véliz, M.; Jurado, F. Hybrid Electric Vehicles: A Review of Existing Configurations 1. Introduction and Thermodynamic Cycles.
    [Show full text]
  • (12) Patent Application Publication (10) Pub. No.: US 2010/0180875 A1 Meldolesi Et Al
    US 20100180875A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2010/0180875 A1 Meldolesi et al. (43) Pub. Date: Jul. 22, 2010 (54) SEATING CONTROL DEVICE FOR A VALVE Publication Classification FOR A SPLTCYCLE ENGINE (51) Int. C. (75) Inventors: Riccardo Meldolesi, Brighton FO2B 33/22 (2006.01) (GB); Stephen Peter Scuderi, FI6K 25/00 (2006.01) Westfield, MA (US) (52) U.S. Cl. ....................................... 123/70 Rs 251/175 Correspondence Address: (57) ABSTRACT EDWARDS ANGELL PALMER & DODGE LLP A seating control device for a valve, comprising: P.O. BOX SS874 a vessel for containing a fluid; BOSTON, MA 02205 (US) an upper snubber element translatably receivable in the (73) Assignee: The Scuderi Group, LLC, West vessel for controlling the seating Velocity of a valve Springfield, MA (US) associated therewith; and a lower snubber element translatably receivable in the ves (21) Appl. No.: 12/321,640 sel, adjacent the upper Snubber element, presenting a surface to the upper snubber element, for controlling the (22) Filed: Jan. 22, 2009 seating of the valve. 62 Patent Application Publication Jul. 22, 2010 Sheet 1 of 13 US 2010/0180875 A1 FIG. 1 Prior Art 18 ° 22 28 2632/ 4. A%214 NR tRNILE N 2 74 % 12 P % 14 Tin - O % |RLNji Patent Application Publication Jul. 22, 2010 Sheet 2 of 13 US 2010/0180875 A1 FIG. 2 Prior Art Valve Lift 45 42 Crank Angle (deg) 43 FIG. 3 Prior Art LO O N 2No. 2NN N Nº 3 3 2\, 3. 22 2% % YERNAL7 ANNau Air H-. 12 release exce Hern --- - Co % ( , r16 Patent Application Publication Jul.
    [Show full text]
  • RECIPROCATING ENGINES Franck Nicolleau
    RECIPROCATING ENGINES Franck Nicolleau To cite this version: Franck Nicolleau. RECIPROCATING ENGINES. Master. RECIPROCATING ENGINES, Sheffield, United Kingdom. 2010, pp.189. cel-01548212 HAL Id: cel-01548212 https://hal.archives-ouvertes.fr/cel-01548212 Submitted on 27 Jun 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution - NonCommercial| 4.0 International License Mechanical Engineering - 14 May 2010 -1- UNIVERSITY OF SHEFFIELD Department of Mechanical Engineering Mappin street, Sheffield, S1 3JD, England RECIPROCATING ENGINES Autumn Semester 2010 MEC403 - MEng, semester 7 - MEC6403 - MSc(Res) Dr. F. C. G. A. Nicolleau MD54 Telephone: +44 (0)114 22 27700. Direct Line: +44 (0)114 22 27867 Fax: +44 (0)114 22 27890 email: F.Nicolleau@sheffield.ac.uk http://www.shef.ac.uk/mecheng/mecheng cms/staff/fcgan/ MEng 4th year Course Tutor : Pr N. Qin European and Year Abroad Tutor : C. Pinna MSc(Res) and MPhil Course Director : F. C. G. A. Nicolleau c 2010 F C G A Nicolleau, The University of Sheffield -2- Combustion engines Table of content -3- Table of content Table of content 3 Nomenclature 9 Introduction 13 Acknowledgement 16 I - Introduction and Fundamentals of combustion 17 1 Introduction to combustion engines 19 1.1 Pistonengines..................................
    [Show full text]
  • The Recuperated Split Cycle – Experimental Combustion Data from a Single Cylinder Test Rig
    2017-24-0169 The recuperated split cycle – experimental combustion data from a single cylinder test rig Author, co-author ( Do NOT enter this information. It will be pulled from participant tab in MyTechZone ) Affiliation ( Do NOT enter this information. It will be pulled from participant tab in MyTechZone ) Critical deadlines – Review ready 16 th March, final manuscript 10 th June Abstract research in the field. Significant benefits through vehicle and system measures, such as kinetic energy recovery and improved aerodynamics are expected to deliver substantial improvements but the primary The conventional Diesel cycles engine is now approaching the source of loss in the system, the prime mover, is more challenging. practical limits of efficiency. The recuperated split cycle engine is an Reductions in powertrain friction and improvements in combustion alternative cycle with the potential to achieve higher efficiencies than efficiency are likely to deliver brake efficiencies as high as 50% from could be achieved using a conventional engine cycle. In a split cycle conventional compression ignition technologies [1]. The addition of engine, the compression and combustion strokes are performed in waste heat recovery will also drive performance beyond 50%, but there separate chambers. This enables direct cooling of the compression is a broad consensus that brake efficiencies in the range of 50-55% cylinder reducing compression work, intra cycle heat recovery and low represents the technology limit from an advanced compression ignition heat rejection expansion. Previously reported analysis has shown that propulsion system with waste heat recovery. brake efficiencies approaching 60% are attainable, representing a 33% improvement over current advanced heavy duty diesel engine.
    [Show full text]
  • Efficiency of Atkinson Engine at Maximum Power Density Using Temperature Dependent Specific Heats
    Volume 2, Number 2, Jun. 2008 ISSN 1995-6665 JJMIE Pages 71 - 75 Jordan Journal of Mechanical and Industrial Engineering Efficiency of Atkinson Engine at Maximum Power Density using Temperature Dependent Specific Heats A. Al-Sarkhi, B. Akash *, E. Abu-Nada and I. Al-Hinti Department of Mechanical Engineering, Hashemite University, Zarqa, 13115, Jordan Abstract Thermodynamic analysis of an ideal air-standard Atkinson cycle with temperature dependant specific heat is presented in this paper. The paper outlines the effect of maximizing power density on the performance of the cycle efficiency. The power density is defined as the ratio of the power output to the maximum cycle specific volume. It showed significant effect on the performance of the cycle over the constant specific heat model. The results obtained from this work can be helpful in the thermodynamic modeling and in the evaluation of real Atkinson engines over other engines. © 2008 Jordan Journal of Mechanical and Industrial Engineering. All rights reserved Keywords: Atkinson engine; power density; temperature dependant specific heat; specific heats of air (the working fluid) were used. The maximization of the power density is defined as the ratio 1. Introduction of the maximum power to the maximum specific volume in the cycle. It takes into consideration the engine size The Atkinson cycle (the complete expansion cycle) is instead of just maximizing its power output. The inclusion named after its inventor James Atkinson in 1882 [1]. As of the engine size in the calculation of its performance is a shown in Fig. 1, the cycle involves isentropic compression very important factor from an economical point of view.
    [Show full text]
  • Performance Analysis of an Atkinson Cycle Engine Under Effective Power
    Vol. 132 (2017) ACTA PHYSICA POLONICA A No. 4 Performance Analysis of an Atkinson Cycle Engine under Effective Power and Effective Power Density Conditions G. Gonca∗ Yildiz Technical University, Naval Arch. and Marine Eng. Depart., Besiktas, Istanbul, Turkey (Received November 16, 2016; in final form May 20, 2017) This study presents performance optimization of an Atkinson cycle engine using criteria named as effective power and effective power density conditions. The effects of design and operating parameters such as compression ratio, cycle pressure ratio, cycle temperature ratio, equivalence ratio, bore/stroke ratio, inlet temperature, inlet pressure, engine speed, friction coefficient, mean piston speed and stroke length, on the performance characteristics have been examined. Moreover, the energy losses have been determined as fuel energy and they have been classified as incomplete combustion losses, friction losses, heat transfer losses, and exhaust output losses. Realistic values of specific heats have been used depending on temperature of working fluid. The results of the study can be assessed as an engineering tool by the Atkinson cycle engine designers. DOI: 10.12693/APhysPolA.132.1306 PACS/topics: gasoline engine, Atkinson cycle, engine performance, power density, finite-time thermodynamics 1. Introduction on artificial neural network technique. Gahruei et al. [28] compared the performances of dual Diesel cycle and dual In the recent years, the researchers carried out several AC based on the FTT by considering irreversible energy studies [1–21] on the Miller cycle (MC) engine to dimin- losses. It was observed from the results that the perfor- ish NOx emissions by reducing the maximum combus- mance of dual AC are higher than that of dual Diesel tion temperatures of the engines.
    [Show full text]
  • Thermodynamics of Power Generation
    THERMAL MACHINES AND HEAT ENGINES Thermal machines ......................................................................................................................................... 1 The heat engine ......................................................................................................................................... 2 What it is ............................................................................................................................................... 2 What it is for ......................................................................................................................................... 2 Thermal aspects of heat engines ........................................................................................................... 3 Carnot cycle .............................................................................................................................................. 3 Gas power cycles ...................................................................................................................................... 4 Otto cycle .............................................................................................................................................. 5 Diesel cycle ........................................................................................................................................... 8 Brayton cycle .....................................................................................................................................
    [Show full text]
  • THESIS WASTE HEAT RECOVERY from a HIGH TEMPERATURE DIESEL ENGINE Submitted by Jonas E. Adler Department of Mechanical Engineerin
    THESIS WASTE HEAT RECOVERY FROM A HIGH TEMPERATURE DIESEL ENGINE Submitted by Jonas E. Adler Department of Mechanical Engineering In partial fulfillment of the requirements For the Degree of Master of Science Colorado State University Fort Collins, Colorado Fall 2017 Master’s Committee: Advisor: Todd M. Bandhauer Daniel B. Olsen Sybil E. Sharvelle Copyright by Jonas E. Adler 2017 All Rights Reserved ABSTRACT WASTE HEAT RECOVERY FROM A HIGH TEMPERATURE DIESEL ENGINE Government-mandated improvements in fuel economy and emissions from internal combustion engines (ICEs) are driving innovation in engine efficiency. Though incremental efficiency gains have been achieved, most combustion engines are still only 30-40% efficient at best, with most of the remaining fuel energy being rejected to the environment as waste heat through engine coolant and exhaust gases. Attempts have been made to harness this waste heat and use it to drive a Rankine cycle and produce additional work to improve efficiency. Research on waste heat recovery (WHR) demonstrates that it is possible to improve overall efficiency by converting wasted heat into usable work, but relative gains in overall efficiency are typically minimal (~5-8%) and often do not justify the cost and space requirements of a WHR system. The primary limitation of the current state-of-the-art in WHR is the low temperature of the engine coolant (~90°C), which minimizes the WHR from a heat source that represents between 20% and 30% of the fuel energy. The current research proposes increasing the engine coolant temperature to improve the utilization of coolant waste heat as one possible path to achieving greater WHR system effectiveness.
    [Show full text]
  • Steam Consumption of Pumping Machinery
    Steam Consumption of Pumping Machinery HENRY EZRA KEENEY THESIS FOR THE DEGREE OF BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING IN THE COLLEGE OF ENGINEERING OF THE UNIVERSITY OF ILLINOIS PRESENTED JUNE, 19Q0 THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION BY ____________ ______ Henry.Ezra.Keeney........_... entitled..s.ta.ara.C.an8mp.i.io.n.....Q.£ ...Bumping.. Machinery. IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE o f ....Bachelor.of.Science.in.Mechanical...Engineering.* h e a d o f d e p a r t m e n t o f ........Mechanical.Engineering, ' INTRODUCTION. Those who have not considered the subject of water distribu­ tion* may not believe that pumping machinery stands at the head of the various branches of Engineering. As to the truth of this state­ ment, we 'nave only to consider that coal could not be obtained with­ out the pumping engine; our water supply for boilers and our city water supply would be difficult of management if it were not for the pump. ”’ater is found in every mine, to a greater or less extent, and the first applications of steam were for pumping the water out of these mines. HISTORY AND DEVELOPMENT. Many forms of puraps were used for obtaining water, but not until the 17th century was steara used for pumping water. So man­ ifest was the economy of steam pumps over those driven by horses, (which were previously used to a great extent) even at the begin­ ning, that they were introduced as rapidly as they could be fur­ nished with the limited supply of tools at the command of the en­ gine and boiler builders of that day.
    [Show full text]