This content is not included in your SAE MOBILUS subscription, or you are not logged in.
A Dynamic Test Bench for the Assessment of Common Rail Fuel Injection Systems Impact on CO 2 Emissions over the WLTP Cycle
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 02, 2019 by SAE International in United States
Annotation ability available
The internal combustion engine technological development is today driven by the pollutants and carbon dioxide (CO2) emission reduction targets imposed by law. The request of lowering CO2 emission reflected in a push towards the improvement of engine efficiency, without sacrificing performances and drivability.
The latest generations of Diesel engines for passenger cars are characterized by increasing injection pressure levels (250 MPa for the current production). Enhancing the injection pressure has the drawback of increasing the energy needed to pressurize the fuel and thus the high-pressure fuel pump energy request. A small but not negligible quantity of fuel has to be burned in order to provide this energy, generating a contribution in CO2 emission. In this frame, the injector back-flow represents a significant energy loss for the fuel injection system and for the whole engine.
The energetic analysis of the overall fuel injection system of a modern passenger car is therefore interesting.
In this research an experimental test bench was developed in order to energetically assess the behavior of a common-rail fuel injection system over the Worldwide harmonized Light vehicles Test Procedure (WLTP) driving cycle. The hydraulic and mechanical energy related to the fuel pump were determined, along with the corresponding CO2 emission. With the proposed test procedure is possible to split the energetic cost into the contributions from injected fuel and back-flow, allowing a comprehensive energetic assessment. Two different configurations of the fuel injection system were tested, differing in the fuel injector type. A standard, latest generation low-leakage injector model was tested and compared to a zero-leakage injector, featuring a particular architecture that should ensure very low back-flow rates.
The results showed that the fuel injection system of a passenger car engine in the power range 55 - 65 kW/l absorbs 142.8 kJ of mechanical energy over the WLTP cycle, being responsible of 1.18 g/km of CO2 emission (1.3% of the total emission).
The low-leakage injectors mounted on the same fuel injection system showed a 24% energy reduction and 0.29 g/km saving of CO2. In the analyzed setup, the low back-flow benefits are partially balanced by a pump volumetric efficiency reduction due to the lower operating flow-rate.
CitationCavicchi, A., Postrioti, L., and Pesce, F., "A Dynamic Test Bench for the Assessment of Common Rail Fuel Injection Systems Impact on CO2 Emissions over the WLTP Cycle," SAE Technical Paper 2019-01-0292, 2019, https://doi.org/10.4271/2019-01-0292.
- Tiegte , U. , Díaz , S. , Mock , P. , German , J. et al. From Laboratory to Road: A 2016 Update of Official and ‘Real-World’ Fuel Consumption and CO2 Values for Passenger Cars in Europe 2016
- Ntziachristos , L. , Mellios , G. , Tsokolis , D. , Keller , M. et al. In-Use vs. Type-Approval Fuel Consumption of Current Passenger Cars in Europe Energy Policy 67 403 411 2014 10.1016/J.ENPOL.2013.12.013
- Andersson , J. , May , J. , Favre , C. , Bosteels , D. et al. On-Road and Chassis Dynamometer Evaluations of Emissions from Two Euro 6 Diesel Vehicles SAE Int. J. Fuels Lubr. 7 3 2014 01-2826 2014 10.1109/WCICA.2010.5554354
- Mock , P. , Kühlwein , J. , Tietge , U. , Franco , V. et al. The WLTP: How a New Test Procedure for Cars Will Affect Fuel Consumption Values in the EU ICCT White Pap. 2014 9 1 20 2014 10.1016/j.enpol.2013.12.013i
- Pavlovic , J. , Ciuffo , B. , Fontaras , G. , Valverde , V. et al. How Much Difference in Type-Approval CO2 Emissions from Passenger Cars in Europe can be Expected from Changing to the New Test Procedure (NEDC vs. WLTP)? Transp. Res. Part A Policy Pract. 111 136 147 2018 10.1016/j.tra.2018.02.002
- Pavlovic , J. , Marotta , A. , and Ciuffo , B. CO2 emissions and Energy demands of Vehicles Tested Under the NEDC and the New WLTP Type Approval Test Procedures Appl. Energy 177 2016 661 670 2016 10.1016/j.apenergy.2016.05.110
- Dimaratos , A. , Tsokolis , D. , Fontaras , G. , Tsiakmakis , S. et al. Comparative Evaluation of the Effect of Various Technologies on Light-Duty Vehicle CO2 Emissions over NEDC and WLTP Transp. Res. Procedia 14 3169 3178 2016 10.1016/j.trpro.2016.05.257
- Herrmann , O. , Nakagawa , M. , Kenhard , M. , Schwab , H. et al. Ultra High Pressure and Enhanced Multiple Injection - Potentials for the Diesel Engine and Challenge for the Fuel Injection System Fuel Syst. IC Engines 103 114 2012 10.1533/9780857096043.4.103
- Jia , T.M. , Yu , Y.S. , and Li , G.X. Experimental Investigation of Effects of Super High Injection Pressure on Diesel Spray and Induced Shock Waves Characteristics Exp. Therm. Fluid Sci. 85 399 408 2017 10.1016/j.expthermflusci.2017.03.026
- Xu , Q. , Xu , M. , Hung , D. , Wu , S. et al. Diesel Spray Characterization at Ultra-High Injection Pressure of DENSO 250 MPa Common Rail Fuel Injection System SAE Technical Paper 2017-01-0821 2017 10.4271/2017-01-0821
- Ulmer , H. , Heilig , A. , Bensch , S. , Schulteis , T. et al. The Potential of the Low-Pressure Path of Diesel Common- Rail Systems in Reducing CO2-Emissions SAE Technical Paper 2016-01-2215 2016 10.4271/2016-01-2215
- De Cesare , M. , Parotto , M. , Covassin , F. , and Sgatti , S. Electric Low Pressure Fuel Pump Control for Fuel Saving SAE Technical Paper 2013-01-0339 2013 10.4271/2013-01-0339
- Brown , A. and Kotori , D. Dynamic Vehicle Powertrain Model Development and Hardware-in-the-Loop Simulator for Developing and Measuring Fuel Efficient CO2 Reducing Technologies SAE Technical Paper 2013-01-0355 2013 10.4271/2013-01-0355
- Rundo , M. and Squarcini , R. Experimental Procedure for Measuring the Energy Consumption of IC Engine Lubricating Pumps during a NEDC Driving Cycle SAE Int. J. Engines 2 1 1690 1700 2009 10.4271/2009-01-1919
- Carlson , R.B. , Wishart , J. , and Stutenberg , K. On-Road and Dynamometer Evaluation of Vehicle Auxiliary Loads SAE Int. J. Fuels Lubr. 9 1 260 268 2016 10.4271/2016-01-0901
- Postrioti , L. , Malaguti , S. , Bosi , M. , Buitoni , G. et al. Experimental and Numerical Characterization of a Direct Solenoid Actuation Injector for Diesel Engine Applications Fuel 118 316 328 2014 10.1016/j.fuel.2013.11.001