Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 Vehicular Fuel Consumption Simulation and Measurement Dr. Horizon GITANO-BRIGGS University Science Malaysia.

Similar presentations

Presentation on theme: "1 Vehicular Fuel Consumption Simulation and Measurement Dr. Horizon GITANO-BRIGGS University Science Malaysia."— Presentation transcript:

1 1 Vehicular Fuel Consumption Simulation and Measurement Dr. Horizon GITANO-BRIGGS University Science Malaysia

2 Challenges of Field FC and Emissions Individual Vehicle Variation Environmental Factors (Temp, Rain…) Driver Factors (Aggressive, slow) Load Factors (Hills, passengers) Traffic Factors (Jammed, or free flowing) Variation from vehicle to vehicle (identical units) Tuning, Wear, part-to-part variation Model to Model variation Geographic Location Variation Hills, Loads, Traffic, … Page 2 of 32

3 Vehicle FC Modeling Speed-Load model is useful and fairly accurate –but- No acceleration load prediction (can be included, but based on what acceleration?) No Hill prediction (again can be included, but what is the topology?) Gearing can be included, but depends on shift speeds –Shift speeds vary by ~2x depending on driver aggression (3000rpm up shift mellow, 6000 racing) Vehicle tuning: still need some engine data Page 3 of 32

4 Vehicle Power Modeling Page 4 of 32 Vehicle Models can be good predictors of power. They are less accurate at fuel consumption prediction.

5 Individual vehicle FC Variation Vehicle Load con not directly predict FC Relies on knowledge of engine operating point and efficiency Efficiency varies widely based on individual vehicles operation point (speed vs. torque) even at same power Page 5 of 32

6 Effect of Rider Stance, Load, Tire Pressure Individual vehicle Power and FC Page 13 of 29 2 x Power 20% FC

7 FC Review Power = Torque x Speed FC = Power x BSFC (Break Specific Fuel Consumption, gm/kWh) Car on highway: 15Nm, 6000 rpm, BSFC = 600 gm/kWh P = 15 x 6000 x 2π / 60 = 9.4kW FC = 600 * 9.4 = 5640 gm/hour FC = 5640gm / 720gm/liter = 7.8 liters/hour 100km/h => 7.8l/100km => 13km/liter Page 7 of 32

8 Engine BSFC (gm/kWh) Maximum Torque Curve (WOT) Page 8 of 32 Engine Torque Engine Speed

9 Constant Power Curves Power: kW Page 9 of 32 Engine Torque Engine Speed

10 Various Gear Ratios For same power BSFC varies from 290 to 350 (ie. 20%) Page 10 of 32 Engine Torque Engine Speed th 3rd 2nd

11 Engine Technology Not all technologies will have similar patterns of FC or emissions (ie. it is hard to generalize FC/Emissions results) Different technologies give different variations of FC Carbureted 2T loses ~35% of fuel unburned typically At idle it may be >70% due to miss-firing Direct Fuel Injection can run exceptionally lean ay idle - Stratified Gasoline vs. LPG leakage LPG: Based on 1 study ~60% of tanks/systems had significant leaks Gasoline systems will have fewer leaks as more noticeable, but suffer from more pilferage Page 11 of 32

12 Idle Combustion Pressure Comparison Page 12 of 32 Carbureted: fires 1 out of 4 cycles Direct Fuel Injection: More consistent 3 x misfires Late combustion

13 Fleet Vehicle FC Variation Variation: Gearing, Tire Size, Replacement Parts, Wear Vehicle tuning varies (7% are grossly mistuned) Driver behavior variation: 2x variation in acceleration One study found FC ok in city but bad in rural because gearing was the same, and engines were revving too high for rural highway speeds Re-geared for highway speeds and FC greatly improved Probably require>30 vehicle samples for any reasonable estimates Page 13 of 32

14 Dyno vs Road Testing Obvious environmental factors: Temp, rain, road surface 2ndary: Engine temps Even with careful control may still have ~10% variation (road – dyno) While dyno tests may not give exactly the same FC numbers as road tests, they are pretty good at vehicle to vehicle comparisons Strive to get a dyno test to match the road FC, but dont stress! The vehicle to vehicle comparison should still be valid unless the dyno test is totally inappropriate! Page 14 of 32

15 Dynamometry Measurements: good for comparisons Fuel economy of 4-stroke and 2-stoke motorcycles Vehicle fuel economy as function of motorcycle age Page 24 of 29

16 Fuel economy versus engine sizeFuel economy by manufacturer Page 25 of 29 Dynamometry Measurements: good for comparisons

17 Dynamometry Studies part throttle resulting in high pumping losses extra work done to overcome the larger aerodynamic drag Optimum speed for best FE Page 15 of 29 Some studies are much easier to do on a dynamometer

18 Dynamometry Studies Optimum speed for best FE Page 15 of 29 Technology comparison: Carb vs EFI

19 Drive Cycle Comparison ECER40 Msian Urban Cycle Msians accelerate more aggressively, faster and spend less time stopped Page 19 of 32

20 Drive Cycle Analysis: Malaysia 600 motorcycle survey Average mileage 5500km/year Page 20 of 32 Similar speeds and accelerations

21 FUEL CONSUMPTION COMPARISON: Chassis Dyno vs. On-Road Drive cycle Distance (m) Time (s) Fuel Consumed (g) Chassis Dyno Mileage (km/L) On-road Mileage (km/L) Difference (%) Suburban Highway Page 21 of 29 The vehicle was transient dyno tested on a representative drive cycle, and compared with on the road fuel consumption for that mode of driving. Typically there is a 10% difference between the 2 methods.

22 Fuel Consumption and Emissions Factors Typical balanced drive cycle => 42.8 km/l Annual mileage ~ 5,500km/year l/vehicle per year 5,000,000 bbl/year total fuel consumption by motorcycles in Malaysia Typical emissions (New carbureted small 4T motorcycles): gm/kmkg/vehicle/yearkTons/year (Msia) CO: HC: NOx: CO2: Page 22 of 32

23 Effect of Technologies: Carb vs EFI Even if the test pattern doesnt match the road cycle exactly, the differences between various technologies should be obvious: Emissions (gm/km) on the ECE-R40 Test: Carbureted EFI CO: HC: NOx: CO2: Page 23 of 32

24 Field FC Measurements Individual tank fill-ups variation is large (>10%) Probably requires ~10 tank fills (Empty to Full 10x) Data taking sometimes questionable (does the recorder care about data quality?) Running with a calibrated fuel bottle will give accurate results for a given drive. This is SOP for Shell Eco Marathon and similar eco races. Page 24 of 32

25 Field Vehicle Measurements GPS is ok for speed, but it may overestimates speed when slow (dither) Wheel sped pick better: gives good V and A and distance No hill, no load info Simple, inexpensive data loggers can track a vehicles movement for months with high resolution. Page 25 of 32

26 Data Collection: Wheel Speed pickup Sensor Target Inductive sensor reads signal from 2 targets on rear wheel, 180 degrees apart Data from the speed pickup is stored in the portable data logger at 10Hz and later downloaded into the computer. RPM vs Time Page 26 of 32

27 Motorcycle Roll Down Test: GPS vs Wheel Speed Aerodynamic resistance dominates Rolling resistance dominates Notice Model and Wheel Data overlay (good agreement) Page 9 of 29

28 Instrumentation: Advanced Concepts Torque sprocket: Measures both speed and torque at wheel Includes hill and load effects (but not engine efficiency) Torque Spkt + engine speed (from generator signal) can be decent predictor of engine operating condition (speed torque) and thus FC Page 28 of 32 Outer section is separate from inner section. Torque compresses springs, allowing outer section to rotate with respect to inner section. Features on both sections are detected by speed pickup.

29 Instrumentation: Advanced Concepts Torque sprocket: Speed, Torque, and Acceleration (from V) Page 29 of 32

30 Instrumentation: Advanced Concepts In fuel injected vehicles the ECU knows how much fuel is being injected. OBD 2 (On Board Diagnostics) Vehicles can have FC read directly from the ECU On non-OBD EFI systems Injection Duration can easily be measured and combined with injector calibration to get a good FC number Carbureted vehicles can be instrumented with EFI sensors: Measure engine speed and throttle position Can back-calculate FC accurately if you have mapped the engine Page 30 of 32

31 Instrumentation: Advanced Concepts In EFI systems the injector does not open or close instantly. The injector calibration curve will give the fuel delivered based on an injection duration (signal) including both of these effects. Page 31 of 32 Delivered Fuel Injector Signal Duration Injector Signal Flow Rate

32 Instrumentation: Advanced Concepts 2-T LPG EFI used for fuel tracking in bi-fuel motorcycle. In gasoline mode (carbureted) can record info for gasoline FC via separate calculation Page 32 of 32

33 Implications for CDMs Vehicle Measurement are crucial: Wheel speed pickup V and A, and distance are reliable Measuring Torque and speed we can estimate FC well Engine Measurement are getting better: TPS + Engine Speed, and Temp With a calibrated vehicle we can accurately get the FC Higher Resolution data, but on a limited number of vehicles? Road gas bottle test still most reliable: Still will have some variation so need several runs. ~30 vehicles to get a good idea of the FC for a given senario. Page 33 of 32

34 Conclusions We can (and should) use standard tests to compare the emissions/FC benefits of various technologies These tests should be as close to the real operating conditions as possible although standard (ie. dyno) tests may not correlate perfectly with field tests Field tests are a good idea (for final confirmation) but must be well controlled: –Fuel metering should be very carefully controlled –Environmental conditions, loads, speeds, … should all be controlled In-Stitu Instrumentation for monitoring actual usage is probably the best way to go in the long run. This may require further development of instrumentation. Page 34 of 32

35 Thank You

36 36 Contacting Us For more information please contact us via: University Science Malaysia Focus Applied Technologies Lot 1174 Jalan Hutan Lipur Kpg. Sg. Buaya Nibong Tebal Penang, Malaysia + (6016) (Voice) +(604) (Fax)

37 Motorcycle Power Demand frontal area vehicle mass rider and payload mass tire pressure Coefficient of rolling resistance, C rr Coefficient of drag, C d Page 4 of 29

38 Parameters Affecting Fuel Consumption Motorcycle Condition Driving pattern Road Condition Environmental Condition Fuel Consumption Vehicles Emission Operational Cost FactorsEffects Page 2 of 29

39 Motorcycle Driving Patterns Comparison Malaysia Aggressive acceleration/breaking Predominantly as commuters also as delivery and even in construction Very different rules from cars Lots of Motorcycle-only infrastructure West (US, Europe) More steady cruising with mild accelerations Mainly for leisure and occasionally for commuting Follow same rules as cars Page 39 of 32

40 Gear Ratio Effect: +/- 50% effect on FC Typical Seasoned Motorcycle Page 14 of 29

Download ppt "1 Vehicular Fuel Consumption Simulation and Measurement Dr. Horizon GITANO-BRIGGS University Science Malaysia."

Similar presentations

Ads by Google