High efficient SI-engine with ultra high injection pressure Chalmers University]

Transcription

1 High efficient SI-engine with ultra high injection pressure Chalmers University] Event; Energirelaterad forskning, 2017 Gothenburg, Sweden 5 th October 2017 Peter Granqvist President DENSO Sweden

2 0. Agenda 2/14 1. Basic information of the project 2. Introduction & political guide 3. Trade off in optimization of GDI engines 4. Initial results and gap of knowledge 5. This projects objective 6. Project time plan 7. Experimental result (so far) 8. Simulation result (so far) 9. Closing words

3 1. Basic information of the project 3/14 Name of the project Start and finish time of the project Main contributors and other partners The program which the project has received funding Amount contributed High efficient SI-engine with ultra high injection pressure Start time Finish time Main contributors DENSO Partners Chalmers University of Technology Volvo cars FFI (Fordonstrategisk Forskning och Innovation) k SEK.

4 1. Basic information of the project 4/14 Project contributors / partners DENSO introduction - Japanese Automotive parts supplier. - Born ~ people. Key contribution from each party Corporation subsidaries globally. - Local subsidary in Sweden. - Born ~100* people. Sweden Unique engine Hardware and competence - Supporting mainly VCC, Volvo AB, Scania. DENSO / VCC powertrain history - 25 years of successful cooperation - Full EMS system gasoline / Diesel - Recent VEA Gen I got many awards - VED Gen I is Diesel market leader with 2500 bar and i-art technology Unique prototype fuel injection hardware and competence Unique sprays and spray combustion competence World class expertise from vehicle/engine maker, research center and parts maker are connected to make generic study of ultra high GDI pressures. * With contractors

5 2. Introduction and Political guide 5/14 Energy used by the road traffic A B C [Efficicent combustion engines can coontribute highly to reduction of area A, B, C.]. CO2 emission values (g/km), normalized to NEDC CO2 level targets China 2020: Japan 2020:122* US 2025: (Achieved in 2013) 80 EU 2021:95 60 EU 2025:68-78(expected) PN level targets Stage Date Cycle PN #/km Euro NEDC - Euro NEDC Euro 6d 2017 Table 1. PN regulation WLTC (RDE) 2021: 95g/km, 2025: 68-78g/km ( ) Until 2050, transport energy efficiency improvements to reduce fossile is to large extent predicted to come from better combustion engines*. EU CO2 / PN targets very challenging. * Efficient fossile use, Part-electrification & Biofuels

6 2. Introduction and Political guide 6/14 [Our conclusion to motivate this particular study] Until recently, Diesel engines were seen as a significant contributor of CO2 reduction until But, is currently politically questioned (main discussion is around RDE NOx). Battery electrification has high potential, but well to wheel (depending on region, etc.) and cost (system, infrastructure, etc.) is a challenge. The importance to develop efficient (CO2), clean (PN, etc.) SI / Gasoline Direct Injection (GDI)* engines and hybrids now increase (especially for near future). * Main direction is Direct Injection from CO2 point of view.

7 3. Trade off in optimizing GDI engines 7/14 For a given system configuration, to reduce both CO2 and PN/PM simultaenously is difficult. GDI ENGINE OPTIMIZATION TRADE OFF [Particles] Euro 6d Euro 7? [CO2] For GDI, so far, main tool to resolve trade off is GPF (particulate filter) addition*. * Costly and have several drawbacks/penalties. New tools needed to reduce GDI CO2 / other emission simultaneously. Based on empirical data, we assume, Ultra high injection pressure** can be such enabler (NEXT PAGE). ** Pressures >> 35 MPa.

8 4. Initial results and gap of knowledge 8/14 Initial empirical data indicate higher pressure as enabler to push trade off of CO2 and PN. Generic effect of ultra high pressures (+500 bar) still unknown. Initial survey of 350 bar/ 200 bar comparision To come further and reach generic understanding, the following is needed. 1. Special fuel injection prototypes. 2. Special engine/combustion system prototypes. 3. Spray and combustion state of the art competence (simularion and practical). BSFC [g/kwh]? Higher pressure PN [#/cm3] To get generic understanding of real effects of ultra high GDI pressure effects, special prototype parts and both engine/experiemental/simulation competency is needed.

9 4. Initial results and gap of knowledge 9/14 There have been only limited investigations on spray & engine using above 50 MPa GDI injection pressure. There is no mass production GDI injector & pump durable above 35 MPa so far. Author Year Test type Fuel Max pressure Remark R. Payri 2012 Spray Petro & Diesel G. Hoffmann 2014 Engine & Spray Table 2. Current researches in terms of high fuel pressure spray 150 MPa Mainly focus on the comparison spray behavior with different fuels (petrol and diesel) Gasoline 40 MPa Higher fuel pressure has influence on PM/PN emission (-90% at 20MPa 40MPa) and fuel consumption (- 2% at 20MPa 40MPa) C. Beatrice 2017 Spray Diesel 120 MPa Outwardly opening hollow cone spray test, but this is for diesel engine development

10 5. This projects objective 10/14 Obtain detailed knowledge about the physical phenomena and mechanisms for fuel sprays at ultra high GDI fuel pressures Obtain a spray database of high quality which can be used for CFD modeling Assess the technology as an enabler for reaching the overall target by a combination of the described technologies with renewable fuels and or with other CO2 reducing technologies. Build a prototype engine with high fuel pressure which demonstrates the benefits shown in the project.

11 6. Project time plan 11/ is mainly for spray measurement to understand spray and develop CFD modeling, is mainly for engine testing to investigate actual effects on combustion and emissions Today Experiment part Spray breakup/characterization Data and knowledge exchange Spray induced turbulence and mixture formation Spray optimization & Injector delivery Combustion system characteristics Engine demonstration Optimum combination of injector and fuel pressure CFD part LES mixing simulations spray chamber LES mixing simulations GDI engine Full cycle LES simulations Current status Done test with production injector for benchmark. Prepare high fuel pressure system. High pressure spray test will start from October. CFD model is under development, but in need of data from experiments. Foundation being built to proof the initial assumption, finally on multicylinder engine.

12 7. Experimental Result (so far) 12/14 Purposes Obtain benchmarking of current level Prepare and get know-how for future work with HP system Test type Atomization test (droplet size measurement) Fuel pressure is 10, 20MPa (same as production system) 50mm downstream from injector tip Result Smaller (and more) droplets have more momentum exchange with surrounding air leading to more air turbulence, better mixing and better evaporation. This combined leads to a better combustion quality. Next step in 2017 Spray formation and atomization investigation with high fuel pressure (max 150MPa) Possibility Diameter [mm] 25% 20% 15% 10% % 0% 10MPa 20MPa 40MPa (assumption) 80MPa (assumption) Smaller droplets Diameter [mm] Mean diameter SMD Velocity Fuel pressure [MPa] Velocity [m/s]

13 8. Simulation Result (so far) 13/14 CFD modeling Purpose Calibrate and develop the spray model to be used for higher pressure sprays Improve spray model accuracy Result The reason why the difference of diameter results occur is under investigation. This model was made with limited experimental data, as an initial test of the model. It is important to calibrate and verify the final model by experimental data at different conditions. Next step in 2017 Develop the spray model further by using the output from the high fuel pressure spray experiments Penetration length [mm] Diameter [mm] Experiment Simulation Exp. Mean diameter Exp. SMD CFD Mean diameter CFD SMD Time [ms]

14 9. Closing words 14/14 - Until 2050, significant energy efficicency improvements likely to come from combustion engine (fossile fuel, Biofuels and Electrification). - In current political climate and regional diversity, GDI engines are increasing in importance. - There is trade-off in GDI engine optimization that we assume, ultra high injection pressure can support (less PN, better combusion quality, etc.). - Direct and secondary effects (combining with other tech) CO2 reduction potential is >10% (VCC VEP MP Gen I GDI engine reference). - Initial results indicate assumptions are correct. Therefore making a generic study involving key expertise in engine, fuel system and spray/combustion is benefical not only to this projects participants but to global automotive industry. Thank you for your time. Any questions?

15 THANK YOU FOR YOUR KIND ATTENTION!!