1. Submitted by- Deepak Jhalani 2008UME409 B.Tech. Final year Student Department of Mechanical Engineering

2.  One of the key feature of Electric and hybrid vehicle.  KERS (Kinetic Energy Recovery System) technology takes a moving vehicle’s kinetic energy, which is otherwise wasted during braking, stores it, and then releases it back into the drivetrain as the vehicle accelerates.  As the name suggests in such brake mechanisms energy lost in conventional brake due to friction is converted to some form that can be reused again 2Ref. Number 6, 7, 12

3.  On an average automobile brakes accounts for around 50% of the total losses that occur in an urban vehicle. Hence making it the largest share holder of the total energy lost.  The regenerative braking captures about 70% of the kinetic energy produced during braking.  Fully loaded medium sized Diesel truck weighing 25 tons, running at 30 km/hr. for an urban service truck which is supposed to cover a distance of 10 km, with expected stop at every 200 m due to traffic and service compulsions, can have a loss of about 60% only due to braking. 3Ref. Number 13, 14

4.  Only “waste energy” is utilized.  Increases fuel economy by 25-45%.  Wear Reduction, So brakes life increases.  CO 2 emissions also decreases because of higher fuel economy.  e.g.-DMRC stopped the emission of 90,004 tonnes of carbon dioxide from 2004 to 2007 by adoption of regenerative braking systems in the Delhi Metro trains. Ref. Number6,7,9,11,12,17,194

5.  CVT-Continuously Variable Transmissions don't have a gearbox with a set number of gears, which means they don't have interlocking toothed wheels. The most common type of CVT operates on an ingenious pulley system that allows an infinite variability between highest and lowest gears with no discrete steps or shifts.  Hybrid Vehicle-The most basic definition of a hybrid vehicle is one that uses two methods of providing power to the wheels. The different categories are:  1. Micro hybrids, which could be based on a 12 Volt Belted Alternator Starter system, approximately 1 to 5 kW.  2. Mild hybrids which are the next step in hybridization enabling additional features such as regenerative braking and launch assist.,is in the range from 5 to 20 kW.  3. Full hybrid, which uses the same features as the two earlier mentioned hybrid types but it, has a greater installed electric power than the other two ranging from 20 kW to more than 100kW and system voltages up to 500 Volts or even more. Ref. Number 12,135

6.  There are basically 3 types of regenerating Braking possible on the basis of HESS (Hybrid Energy Storage Systems)-  1.Mechanical or flywheel based  2.Hydraulic based  3.Electrical-  3.a –Battery  3.b-Battery with Ultra Capacitor  3.c-Battery,Ultra Capacitor, Switch and BMS 6Ref. Number 1,3,6,7,11,12,13

7. 7Ref. Number 3,11 Often, the starting current reaches a 10 C to 15 C rate.A simple, parallel- connected HESS is not sufficient to manage the high current charging that is caused by regenerative braking; however, it results in some improvement in the efficiency and cycle life compared to the battery alone.

8. 8Ref. Number 3 According to the test results, the battery alone exhibits a capacity decrease of approximately 33%, whereas the HESS decreases less than 5%. Furthermore, the advanced HESS with a selective connecting function exhibits a capacity increase of 5.5% because the appropriate switching scheme encourages the usage of the highly efficient ultracapacitor.

9.  Hydraulic systems are used to mechanically store energy from a vehicle in motion. Hydraulic accumulators incorporated in passenger cars and buses store and provide energy. 9Ref. Number 2,13,14,20

10. 10Ref. Number 1,6,13 The system utilizes a flywheel as the energy storage device and a Continuously Variable Transmission (CVT) to transfer energy to and from the driveline. A clutch allows disengagement of the flywheel when not used. Transfer of vehicle kinetic energy to flywheel kinetic energy reduces the speed of the vehicle and increases the speed of the flywheel. Transfer of flywheel kinetic energy to vehicle kinetic energy reduces the speed of the flywheel and increases the speed of the vehicle.

11. 11Ref. Number 13 A simple Epicyclic gearbox

12. 12Ref. Number 13 The system has three modes of operation: 1. Flywheel Assisted Acceleration-In this mode, energy is withdrawn from the flywheel to the vehicle. 2. Regenerative Braking- In this mode, the flywheel captures energy from the vehicle. 3. Neutral- In this mode, there is no transmission of energy and the components of the system rotate freely. Then vehicle kinetic energy gets converted into Flywheel kinetic energy flywheel’s kinetic energy will be transmitted to help accelerate the vehicle If motor speed more than critical speed YESNO

13. 13Ref. Number 8,9

14. 14Ref. Number 1 The configuration with the 4 litre engine and KERS corresponds to a fuel economy of 8.8 litres/100 km over the urban sector (fuel saving of more than 35%), and 7.7 litres/100 km over the full cycle (fuel saving of 25%).

15. 15Ref. Number 1  The configuration with the 1.6TDI Diesel engine and KERS reduces the fuel usage to 3.16 litres per 100 km, corresponding to a production of 82.4 g of CO2 per km. These CO2 values are 7% better than those of today’s best hybrid electric vehicle.  Downsizing the engine to 1.2 litres, the fuel consumption is reduced to 3.04 litres per 100 km, corresponding to a production of 79.2 g of CO2 per km. These CO2 values are 11% better than those of today’s best hybrid electric vehicle.

16. Ref. Number 116 The configuration with the 11TDI engine and KERS requires 2.15 kg of fuel to cover the full cycle. This corresponds to a fuel economy of 23.8 litres/100 km over the full cycle with a fuel saving of 25%.

17. 17Ref. Number 1,6,13 Electric Have a number of energy conversions, So overall system efficiency is 35% only. But better for long time energy storage Component life restricted. Hydraulic Have a comparatively high efficiency (around 70%). But have high complexity and amount of space required is high. Mechanical Have a high efficiency around 70%. For short time energy storage. Simple is construction and low in weight. Component life significantly unaffected by the drive cycle experienced

18. 18Ref. Number 18 Electric Hybrid Vehicle Number of vehicle sold * Chevrolet Volts302 Nissan Leafs1,362 Hyundai Sonata Hybrid 4,136 Lexus' hybrids3238 Honda Insight961 Honda CR-Z745 Toyota Prius9,491 *-all sales figure are for Aug.2011 for American Market All these Vehicles are having Regenerati ve Braking

19.  EPA(U.S. Environmental protection agency), in cooperation with its partners, has successfully installed and tested hydraulic hybrid technology in a variety of vehicles. These demonstration vehicles, featured below, have shown tangible real-world results, including fuel economy improvements of 30 percent to over 100 percent over their conventional counterparts.  Crysler is working along with EPA, expecting to launch first commercial vehicle by 2013 Ref. Number 14,2019

20.  In late 2007, governing body the FIA announced it was freezing the specification of F1engines for the next 10 years to encourage car makers to develop environmentally friendly technologies such as KERS. For the first time in history for 2009 Melbourne Grandprix, it was mandatory.  Flybrid has been able to create enough power storage density in a unit small enough and light enough (25kg) for F1 by making the flywheel spin at about 64,000rpm. 20Ref. Number 6,13,17

21.  First production road-car with mechanical hybrid is 2013,Jaguar and Flybrid are working for it. This is an UK government funded project. 21Ref. Number 6,13,17 The Flybrid® 9013 hybrid system as fitted to the Jaguar XF demonstrator

22.  1.Alberto Boretti,IMPROVEMENTS OF VEHICLE FUEL ECONOMY USING MECHANICAL REGENERATIVE BRAKING,Copyright © 2010 SAE International,2010-01-1683.  2.Triet Hung HO1 and Kyoung Kwan AHN2, Modeling and simulation of hydrostatic transmission system with energy regeneration using hydraulic accumulator†, Journal of Mechanical Science and Technology 24 (5) (2010) 1163~1175.  3. D.-H. SHIN1), B.-H. LEE2), J.-B. JEONG3), H.-S. SONG4) and H.-J. KIM5)*, ADVANCED HYBRID ENERGY STORAGE SYSTEM FOR MILD HYBRID ELECTRIC VEHICLES, International Journal of Automotive Technology, Vol. 12, No. 1, pp. 125−130 (2011)  4. D. PENG1)*, Y. ZHANG2), C.-L. YIN3) and J.-W. ZHANG3), COMBINED CONTROL OF A REGENERATIVE BRAKING AND ANTILOCK BRAKING SYSTEM FOR HYBRID ELECTRIC VEHICLES, International Journal of Automotive Technology, Vol. 9, No. 6, pp. 749−757 (2008)  5. J. K. AHN, K. H. JUNG, D. H. KIM, H. B. JIN, H. S. KIM and S. H. HWANG, ANALYSIS OF A REGENERATIVE BRAKING SYSTEM FOR HYBRID ELECTRIC VEHICLES USING AN ELECTRO- MECHANICAL BRAKE, International Journal of Automotive Technology, Vol. 10, No. 2, pp. 229−234 (2009)  6. www.theiet.org/engtechmag Engineering & Technology 22 November - 5 December 2008  7. Z.L. Han1, a, Y.Y. Wang1, b, On the Study of Electric Vehicle Regenerative Braking, Applied Mechanics and Materials Vol. 33 (2010) pp 273-275  8. Donghyun Kim and Hyunsoo Kim, Vehicle Stability Control with Regenerative Braking and Electronic Brake Force Distribution for a Four-Wheel Drive Hybrid Electric Vehicle, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 2006 220: 683  9. Sungwook J ang,Hoon Yeo,Chulsoo Kim,Hyunsoo Kim, A Study on Regenerative Braking for a Parallel Hybrid Electric Vehicle, KSME International Journal, VoL 15 No. 11, pp. 1490-1498, 2001 22Ref. Number

23.  10. P Moriarty* and D Honnery, Slower, smaller and lighter urban cars, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 1999 213: 19  11. Linus Nordholm, Dept. of Industrial Electrical Engineering and Automation,Lund University,Master Thesis, Development of validation methods for HEV (Hybrid Electrical Vehicle), CODEN:LUTEDX/(TEIE-5225)/1-102/(2006 ).(http://www.iea.lth.se/publications/MS- Theses/Full%20document/5225_Development%20of%20validation%20methods%20f%F6r%20HEV.pdf)  12. Gustaff Lagunoff, Lulea University of Technology, Department of Applied physics and Mechanical Engineering, Master Thesis, Automotive Hybrid Technology, Status Functions and development Tools, 2008:217CIV - ISSN:1402-1617-ISRN:LTU-EX--08/217—SE ( www. epubl.ltu.se/1402-1617/2008/217/LTU-EX-08217-SE.pdf )  13. Ulises Diego-Ayala, Department of Mechanical Engineering, Imperial College London February 2007, Doctor of Philosophy of the University of London and the Diploma of Imperial College,AN INVESTIGATION INTO HYBRID POWER TRAINS FOR VEHICLES WITH REGENERATIVE BRAKING ( www.rutasdesalida.com/PhD_Thesis_Imperial_College_Ulises_Diego_Ayala.pdf)  14.http://www.eaton.com/Eaton/ProductsServices/ProductsbyCategory/HybridPower/Applications /index.htm (retrieved on 28 Sep. 2011)  15. http://www.formula1.com/news/headlines/2010/5/10723.html (retrieved on 28 Sep. 2011)  16.http://www.bbc.co.uk/blogs/andrewbenson/2009/04/what_is_the_future_for_kers.html (retrieved on 29Sep. 2011)  17. http://www..flybridsystems.com/Roadcar.html (retrieved on 24Sep. 2011)  18. http://www.insideline.com/nissan/leaf/nissan-leaf-beats-chevy-volt-again-in-monthly- sales-race.html (retrieved on 24Sep. 2011)  19. http://www.delhimetrorail.com/whatnew_details.aspx?id=spzgQyC0reYlld (retrieved on 28 Sep. 2011)  20. http://www.epa.gov/oms/technology/research/demonstration-vehicles.htm#UPS (retrieved on 28 Sep. 2011) 23Ref. Number

24. 24Ref. Number