1 / 50

Downsized and Supercharged Hybrid-Pneumatic Engine

Downsized and Supercharged Hybrid-Pneumatic Engine. C. Dönitz, C. Onder, I. Vasile, C. Voser, L. Guzzella. Nothing New (the Parsey Locomotive, 1847). Source: http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/comprair/comprair.htm. Dickson Locomotive, 1899.

strom
Download Presentation

Downsized and Supercharged Hybrid-Pneumatic Engine

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Downsized and Supercharged Hybrid-Pneumatic Engine C. Dönitz, C. Onder, I. Vasile, C. Voser, L. Guzzella

  2. Nothing New (the Parsey Locomotive, 1847) Source: http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/comprair/comprair.htm

  3. Dickson Locomotive, 1899 Mass 16 t, storage 40 bar, working 10 bar, volume 4.8 m3 Source: http://www.dself.dsl.pipex.com/MUSEUM/TRANSPORT/comprair/comprair.htm

  4. Compressed Air as Fuel? 45 MJ/100km η2= 44% η4= 80% Ptank=300 bar Ttank= 300 K η1= 90% η3= 81% Necessary energy in air tank 70 MJ, which corresponds to 320 kg air mass and 200 kg tank mass (kevlar composite) and 925 l tank volume. Compare that to BEV: plug-to-wheel efficiency of ηtot= 0.75 and 150 kg battery mass (Li-ion batteries with 100 Wh/kg useful energy density).

  5. Pneumatic Hybrid Powertrains? • Internal combustion engine as range extender: too many components and poor fuel economy • Hybrid pneumatic engine: • 1 main energy supply • 1 energy buffer • 1 energy conversion device

  6. Directly vs. Indirectly Connected Air Tank Indirectly Connected Air Tank: + Only limited changes in valve actuation system needed • No major cylinder head changes • Mode changes difficult/restricted • Reduced actual pumping compression ratio Directly Connected Air Tank • Add charge valve actuation to system • Cylinder head redesign • Mode changes easy • Pumping compression ratio not compromised Adapted from: A. Fazeli, A. Khajepour, C. Devaud, and N. Lashgarian Azad. A new air hybrid engine using throttle control. SAE Paper 2009-01-1319

  7. • “downsizing” V-6R-3 • “supercharging” 0.36 0.35 0.33 0.3 0.25 0.2 0.1 Downsizing and Supercharging (DSC) Replace a V-6 by an R-3 withturbocharger 0.3 0.33 0.36 0.35 0.25 0.2 0.1 7

  8. x=0.27 Willans Behavior output x=0.37 full load input full load output x=0.17 0 input idle input

  9. Problems DSC ? Drivability

  10. The Hybrid Pneumatic Engine (HPE) Idea Previous work by Herrera (1998), Schechter (1999), and Higelin (2001) Air tank as energy buffer Recuperation and pneumatic driving Pneumatic modes are 2-stroke based, all valves variable

  11. Comparison Valve Actuation Modes 2-stroke modes require variable actuation for all valves 4-stroke concept is cheaper and less complex IV – Intake Valve EV – Exhaust Valve CV – Charge Valve – ETH Modes

  12. The ETH DSC HPE Concept

  13. Operating Modes

  14. Additional Engine Modes Pump mode: throttle always open Pneumatic motor mode: closes throttle for higher torque Supercharged mode: air injection at start of compression - Recharge mode: 2 cylinders conventional, 2 cylinders pump a) b) c)

  15. Simulation Vehicle & Engine Parameters • Base vehicle weight 1450 kg, engine weight: 67kg/l • Rated power: 100kW for all engines, baseline is 2.0l NA gasoline engine • Auxiliaries consume 400 W • Gearbox: manual, 5-speed, η=93% • Mid-size vehicle, • Tank volume 30 liters • Effect of reduced compression ratio on engine efficiencyconsidered • Variable valve actuation energy accounted for according to number of used EHVS.

  16. Baseline Engine as Willans Machine

  17. Engine Scaling • Account for reduced internal efficiency when reducing the compression ratio due to supercharging • Values obtained using engine process simulation

  18. Variable Valve Actuation Energy • Energy demand for EHVS is added to demanded torque • Hydraulic pump efficiency of ηHyd=0.6 assumed • zi is the number of variably actuated valves per 2 revolutions

  19. Simulations (1): Fuel Economy MVEG-95, 1550 kg vehicle

  20. QSS & Dynamic Programming • Additional degree of freedom, additional state: Internal energy of air tank • Use quasi-static simulation (QSS) and engine mode maps and reduce to • Dynamic Programming: • One state: tank pressure • One input: engine mode choice • Disturbance: drive cycle • Cost: fuel consumed

  21. Simulations (2): Influence Tank Volume

  22. Simulations (3): Overcoming the Turbo-lag Simulation for 1500 kg vehicle in 4th gear with 0.75 liter engine

  23. The ETH DSC HPE Test Engine Main Ideas • Strong downsizing to improve fuel economy • Connect pressurized air tank directly to engine cylinders: enables excellent driveability • PFI/stoich gasoline engine • Asymmetric turbo charger Engine Type Additional Hardware: • Variable valve actuation system for CV only • Air tank (cold tank strategy)

  24. Hardware (1): Modified Engine MPE750

  25. Hardware (2): Modified Engine MPE750

  26. Electro-Hydraulic Valve Actuation System • EHVS provides fully variable valve actuation for the CV: opening closing 15.09.2014 K. Mischker and D. Denger. Requirements for a fully variable valvetrain and realization with the electro-hydraulic valvetrain system EHVS. VDI-Fortschritt-Berichte, 12(539), 2003.

  27. Hardware (3): Engine on testbench Air tank 30 liters, steel, not insulated for cold-tank strategy Engine equipped with GT12 compressor & GT14 turbine Electricwastegate actuator

  28. A (virtual) lab visit … or come and visit us!

  29. Hardware (4): Engine Control Systems

  30. Engine Controls:Vehicle Emulation Control Architecture • Dynamometer controls torque (behaves like a vehicle in drive cycle) • Engine controls speed • Supervisory control determines engine mode f(pT)

  31. Measurements (1): The Supercharged Mode

  32. Measurements (2): The Supercharged Mode Test at constant intake pressure (550 mbar)

  33. Measurement (3): Overcoming the Turbolag N = 2000 rpm

  34. Measurements (4): Rapid Pneumatic Start pT = 10 bar • Rapid engine start enables start/stop operation and thus the elimination of idling. • Pneumatic engine start < 350ms for pT= 10 bar.

  35. Optimization Results Pneumatic Modes • Pneumatic motor mode: only for low engine speeds • Pump mode: operating area strongly limited

  36. Measurements (4): Recuperation Efficiency

  37. Remark: Recuperation using Alternator Recuperation: pumping is limited by four-stroke mode In the MVEG-95 ~500 kJ cannot be recuperated by pumping air in braking phases Excess energy can be used for: EHVS actuation: 104 kJ needed to drive MVEG-95 (assuming 60% efficiency for the alternator & 60% efficiency for an electric hydraulic pump) Electric auxiliaries need 300 W at the crankshaft for 1200 s, i.e., 360 kJ are needed for the drive cycle  Fuel consumption can be further reduced

  38. Experiment: VW Polo, MVEG-95

  39. Engine Mode Determined Using DP

  40. Experiment: Nissan Micra, FTP

  41. Engine Mode Determined Using DP

  42. Fuel Consumption Measurement Results • Engines of approximately same maximum power are compared • Comparison to NA SI engines in series production cars Measured Fuel Consumption Reduction (MVEG-95)

  43. Result Overview, MVEG-95

  44. Result for FTP, Nissan Micra Data sources: Touring Club Switzerland www.tcs.ch, EMPA Switzerland, OEM webpages

  45. Electric Hybridization vs. DSC HPE Concept HPE: Estimated added cost for EHVS & tank: 1500 CHF (conservative) DSC & pneum. hybridization electric hybridization For normalization: base rated power 61 kW base weight 1080 kg (Prius base weight 1250 kg)

  46. Thank you for your attention!

  47. Compressed Air in a Series Hybrid? comp. 20 kW 1-stage adiabatic tank, ~50 l pneum.motor 60 kW ICE 20 kW ptank=20-30 bar Ttank= 700-800 K 45 MJ / 100km η4= 81% η5= 80% η3= 80% η1= 35% COP = 1 η2= 80% pneum.motor 60 kW comp. 20 kW 2-stages air tanks ~50 l and ~10 l ICE 20 kW ptank~ 80 bar Ttank= 400 K Expand and heat up 45 MJ / 100km η5= 80% η13= 95% η4= 81% η11= 35% COP = 0.5 η12= 80% η23= 50% Q21= 65% η22= 50%

  48. Reproduceability of Measurements Mean measured fuel consumption (g) Deviations from mean values (exemplary, 3 measurements per cycle)

  49. Pneumatic Modes Control • Pneumatic Pump Mode: • Feedforward only • Braking torque is limited a priori if too high • Pneumatic Motor Mode: • Throttle feedforward only • Feedback uses as ΔMV2O as control signal

  50. Supervisory Control – Dynamic Programming • 3 states: tank pressure, old engine mode, and old gear • 2 inputs: engine mode, gear switching • allows engine start & gear switching penalty • For the MVEG-95, gears are pre-defined, so 2 states and 1 input results.

More Related