Advanced Ethanol-Diesel Dual-Fuel Combustion for Heavy-Duty Engines

Transcription

1 Future Powertrain Conference 2017 Advanced Ethanol-Diesel Dual-Fuel Combustion for Heavy-Duty Engines Vinícius Pedrozo* Prof. Hua Zhao Centre for Advanced Powertrain and Fuels - CAPF College of Engineering, Design and Physical Sciences

2 As one of America s governors has said, We are the first generation to feel the impact of climate change, and the last generation that can do something about it. Sources: Source: 2

3 Ethanol as an Alternative Fuel - Renewable; - Low carbon fuel; - Well established use in Brazil. Source: Rape seed 60% reduction vs. fossil fuel comparator Biodiesel Hydrotreated vegetable oil (HVO) from rape seed Soybean Palm oil biodiesel Bioethanol Fossil Waste vegetable/animal oil Wheat ethanol Sugar beet ethanol Sugar cane ethanol Fossil fuel comparator Default GHG emissions (RED Annex V) ILUC IFPRI gco 2 eq / MJ Source: Adapted from Shell, Challenges and Fuels Options for Future HD Transportation, SAE 2016 HDDEC Symposium. 3

4 Research Motivation - Increasingly fuel energy demand and oil dependency; - Stringent emissions regulations. Global transportation demand (Million oil-equivalent barrels per day) 75 Global transportation demand by fuel (Million oil-equivalent barrels per day) 75 Other Natural gas Jet fuel 50 Commercial 50 Fuel oil Diesel Light-duty road Gasoline Source: Adapted from Exxon Mobil Corporation, The Outlook for Energy: A View to

5 Research Objectives - Research advanced dual-fuel combustion strategies; - Achieve efficient engine operation with low exhaust emissions (e.g. Euro VI compliant); - Maximise the use of ethanol in a heavy-duty diesel engine. Direct Injection of Diesel Port Fuel Injection of Ethanol 5

6 Single Cylinder Heavy-Duty Engine Parameter Bore x Stroke Connecting rod length Value 129 x 155 mm 256 mm Swept volume dm 3 Geometric compression ratio 16.8:1 Max. in-cylinder pressure Piston type Diesel injection system Ethanol injection system 18 MPa Re-entrant bowl Bosch Common Rail, max. 220 MPa, 8 holes, 150 spray PFI Marelli IWP069, 300 kpa rel., 15 spray 6

7 Test Cell Diagram 7

8 Methodology - CDC vs. Dual-fuel; - Engine loads: 3 to 15 bar IMEP. - Engine speed: 1200 rpm. - Limitations: EGR rate 25%; PRR 20 bar/cad; COV_IMEP 3%; COV_Pmax 3%. 8

9 Methodology - Diesel injection timings for maximum net indicated efficiency; Up to 80% - Ethanol energy fractions for minimum ISNOx/ISsoot. Ethanol energy fraction = m ethanol LHV ethanol m ethanol LHV ethanol + m diesel LHV diesel 9

10 Combustion Control Pre- and main inj. near TDC at mid/high loads Split inj. (51/49) at mid load Early single inj. at light loads 10

11 Combustion Characteristics PRR 20 bar/cad Shorter and retarded combustion process Higher peak heat release 11

12 Exhaust Emissions Lower consumption of aqueous urea solution in the SCR system EGT below 200 C at 3 bar IMEP 53-84% lower NOx emissions Low levels of smoke 12

13 Exhaust Emissions EGT below 200 C at 3 bar IMEP Higher unburnt HC Higher CO emissions 13

14 Performance Crevice volumes + lower local in-cylinder gas temperatures/φ Lower combustion efficiencies High net indicated efficiencies 14

15 Summary - The introduction of a premixed charge of ethanol into a HD diesel engine was effective in reducing NOx emissions by up to 84%; - The adoption of optimum fuel injection strategies at each engine load was the key enabler for controlling the in-cylinder charge reactivity and PRR s; - Fuel flexibility combined with an efficient dual-fuel combustion and lower NOx emissions can decrease the engine running costs. 15

16 Thank you for your attention! 16