and Electric Vehicles ECEN 2060

Transcription

1 Hybrid Electric Vehicles and Electric Vehicles ECEN 26

2 Vehicle Dynamics F F d F r F a F g 1 d A 2 C 2 f rr M g cos M d dt M g sin Force [N] = traction effort to accelerate (F a ) and to oercome aerodynamic drag F d, rolling resistance F r, graity F g, F Power required: P F 1 C 2 d A 3 f rr M g M d dt M gz 2

3 Example: US6 driing cycle 1 8 [mp ph] P [k kw]

4 ICE ersus Electric Drie Characteristics Internal Combustion Engine Electric Drie: AC machine + Inerter Gasoline energy content: 12.7 kwh/kg, 36.4 kwh/gallon ICE is a thermal engine, efficiency limited to less than 3% Characteristic not well suited for ehicle drie, requires ariable-speed gear box Best aailable battery y( (Li-Ion) specific energy:.1-.2 kwh/kg Efficiency better than 9% Characteristic ery well suited for ehicle drie to meet wide ranges of speed and traction force 4

5 Traction drie characteristic F P drie = const. b max 5

6 US6 driing cycle: aerage power 1 8 Prius-sized ehicle [mp ph] P [k kw] Regeneratie braking P ag = 7. kw

7 US6 driing cycle: aerage power 1 8 Prius-sized ehicle [mp ph] Dissipatie braking P ag = 11.3 kw P [k kw] Regeneratie braking P ag = 7. kw

8 ICE efficiency map 8

9 Hybrid Electric Vehicles (HEV) Combination of a gasoline-powered dice and an electric ti drie with a relatiely small battery HEV efficiency improements Downsizing: a smaller, more efficient ICE ICE operated around the most efficient operating point, not directly tied to the required drie power & speed No idling required when the ehicle stops, keep ICE off Regeneratie braking HEV s are more efficient, but are still conentional, gasolinepowered ehicles Plug-in HEV s (PHEV) or pure electric ehicles (EV) are alternatie-fuel ehicles powered in part or completely from the electric power grid 9

10 Series HEV drie train In a PHEV, a (larger) battery can be charged from the electric power grid F Fuel ICE n 1 T 1 n V 2 T 2 DC n T Electric 3-phase 3-phase Electric motor/ inerter/ Battery inerter/ motor/ generator rectifier rectifier generator Transmission Energy ED1 storage ED2 Battery charging (alternator) Traction Wheels ICE starting Regeneratie braking (radius r ) Example: Chey Volt, a PHEV with a drie-train architecture based on the series architecture: t 62 kw (83 hp, 1.4 L) ICE 55 kw electric drie ED1 111 kw (149 hp) electric drie ED2 1

11 HEV battery sizing: US6 driing cycle 1 8 Prius-sized ehicle [mph] P [kw] Aerage power P ag supplied by the ICE P = P - P ag supplied by the electric drie and battery E [kwh] t E P( ) d SOC min A relatiely.5 kwh small battery is sufficient SOC max 11

12 PHEV or EV drie train F Fuel ICE n 1 T 1 Electric motor/ generator 1 3-phase inerter/ rectifier 1 ED1 Battery charging (alternator) ICE starting V DC Battery Energy storage 3-phase inerter/ rectifier 2 ED2 Traction Electric motor/ generator 2 Regeneratie braking n 2 T 2 Transmission Wheels (radius r ) n T Plug-in hybrid electric ehicle (PHEVX) has a driing range (X miles) as electric ehicle powered by batteries only (EV mode) Example: Chey Volt is a PHEV4, with a 16 kwh battery, 65% (1.5 kwh) usable, and (approximately) 4 miles of EV range (.26 kwh/mile) Electric ehicle (EV), or Battery Electric Vehicle (BEV) does not include ICE at all Example: Tesla Roadster has about 25 miles (4 km) EV range, with about 5 kwh battery, 75% (37.5 kwh) usable (.15 kwh/mile) 12

13 PHEV or EV battery sizing: US6 driing cycle 1 8 Prius-sized ehicle [mph] A much larger battery is required E [kwh] kwh,.15 kwh/mile

14 New EPA stickers: EV example Nissan Leaf EPA miles-per-gallon-equialent ll i l calculation l 1527 kg 8 kw (11 hp) electric drie 24 kwh Li-Ion battery Cells: 14 Wh/kg 3 kg battery pack (8 years, 1, miles warranty) MPG equialent = Trip length [miles] Total energy consumed [kwh] x 33.7 kwh/gallon 14

15 New EPA stickers: PHEV example Chey Volt 172 kg 11 kw (149 hp) electric drie 62 kw (83 hp) ICE 16 kwh Li-Ion battery 175 kg battery pack (8 years, 1, miles warranty) 15