FLAME ANALYSIS TECHNIQUES FOR TC-GDI DEVELOPMENT

Transcription

1 FLAME ANALYSIS TECHNIQUES FOR TC-GDI DEVELOPMENT From injector selection up to RDE calibration E. Winklhofer, G. Fraidl, S. Eder AVL List GmbH (Headquarters)

2 GLOBAL TECHNOLOGY DRIVERS Motivation Customer Demands Vehicle Technology Legislation Driving Experience TCO Electrification Connected Powertrain WLTP An engineer s degrees of freedom : Engine and vehicle technology development must meet legislative boundaries and respond to customer demands and achieve specific targets for Fuel economy Emissions Performance - Cost E. Winklhofer, G. Fraidl, S. Eder 29 Juni

3 The statistics: GLOBAL PRODUCTION FORCAST TOTAL PASSENGER CAR ENGINES Motivation On a global scale, the ICE remains the dominating power source even beyond 2025 Today the TC GDI engine is the fastest growing engine type E. Winklhofer, G. Fraidl, S. Eder 29 Juni

4 SOP - Start of production GDI ENGINE DEVELOPMENT SOME ACTIVITIES AND DECISION POINTS Engine development progress The work environment Simulation and components tests Specification combustion system Multi-cylinder engine development Performance, emissions, durability Vehicle testing months ECU calibration driveability & emissions Which data do we need to conclude on correct decisions? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

5 CONTENT 1: Optical single cylinder engine 3: Chassis dyno 2: Multi-cylinder engine test bed E. Winklhofer, G. Fraidl, S. Eder 29 Juni

6 Test facility data decision 1.1 Optical single cylinder engine Optical engine M1 dual injection M2 triple injection M4 central FRP We use high speed movies to understand spray combustion chamber interaction and resultant premixed and diffusion flame combustion. Target: avoid diffusion flame formation to minimize particle emissions! E. Winklhofer, G. Fraidl, S. Eder 29 Juni

7 Test facility data decision 1.1 Optical single cylinder engine Optical engine 1.2 Data recording and evaluation We use high speed movies to compare hardware options and find FIS parameter combinations for lowest soot formation at acceptable combustion stability. Target: soot / stability performance in selected operating points (cat heating, low end torque, medium / high part load) E. Winklhofer, G. Fraidl, S. Eder 29 Juni

8 Test facility data decision 1.1 Optical single cylinder engine Optical engine 1.2 Data recording and evaluation 1.3 decision: piston and injector 1. The outcome: decision on best choice of injector and piston together with a set of fuel injection parameters for best PN and stability 2. Supportive analysis in optical engine to document fuel mixture formation for selected injector/piston choice E. Winklhofer, G. Fraidl, S. Eder 29 Juni

9 SOP - Start of production GDI ENGINE DEVELOPMENT SOME ACTIVITIES AND DECISION POINTS Engine development progress Simulation and components tests 1 Specification combustion system 1. Handover to thermodynamic (multi-cylinder) engine development Multi-cylinder engine development Performance, emissions, durability Vehicle testing ECU calibration driveability & emissions months Which data do we need to conclude on correct decisions? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

10 SOP - Start of production GDI ENGINE DEVELOPMENT SOME ACTIVITIES AND DECISION POINTS Engine development progress Simulation and components tests 1 2. Test the limits at normal engine operation in stationary Specification combustion system and transient mode 1. Handover to thermodynamic (multi-cylinder) engine development Multi-cylinder engine development Performance, emissions, durability 2 Vehicle testing ECU calibration driveability & emissions months Which data do we need to conclude on correct decisions? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

11 SOP - Start of production GDI ENGINE DEVELOPMENT SOME ACTIVITIES AND DECISION POINTS Engine development progress Simulation and components tests 1 Specification combustion system 2. Test the limits at normal engine operation in stationary and transient mode 1. Handover to thermodynamic (multi-cylinder) engine development Multi-cylinder engine development Performance, emissions, durability 2 Vehicle testing ECU calibration driveability & emissions months Which data do we need to conclude on correct decisions? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

12 Test facility 2.1 Multi-cylinder engine test bed data decision Normal engine Normal engine at unrestricted operation PN sources Flame kernel Knock Combustion analysis in normal engines: Pressure sensors for thermodynamic evaluation: rate of heat release, IMEP, GCA Fiber optic spark plug ( Visiolution ) sensors for flame evaluation: PN sources, knock, pre-ignition, flame kernel stability Pre-ignition E. Winklhofer, G. Fraidl, S. Eder 29 Juni

13 Test facility data decision 2.1 Multi-cylinder engine test bed Knock Sensor Data Knock center statistics Data: the knock event A convenient sensor: the VisioKnock spark plug: we evaluate the sensor signals for the location of the primary knock event. Knock center statistics then yield the basis for potential knock limit improvements E. Winklhofer, G. Fraidl, S. Eder 29 Juni

14 Test facility 2.1 Multi-cylinder engine test bed data decision Knock Knock center distribution VisioKnock exhaust intake Flame kernel propagation VisioFlame The decision: Find means to change flame kernel motion towards direction of main knock centers Which means: port design, squish flow surfaces, cooling Benefit: torque at knock limit (spark advance) E. Winklhofer, G. Fraidl, S. Eder 29 Juni

15 IGNITION AND PRE-IGNITION Pre-ignition Regular Ignition with spark plug Regular Ignition At location of spark plug At selected spark timing Irregular ignition at unknown location at unknown time E. Winklhofer, G. Fraidl, S. Eder 29 Juni

16 IGNITION AND PRE-IGNITION Pre-ignition Regular Ignition with spark plug Pre-ignition (PI): ignition energy is provided by compression, heat exchange with combustion chamber surface, deposits, lube oil and any combination thereof. The Pre-ignition event schematic Irregular Ignition by unknown pre-ignition source In order to prevent pre-ignition (PI) we need to understand the root cause mechanisms. We use data on PI occurrence, timing and location to understand possible root causes and to find improvements. Task 1: operate engine under risk of PI and collect PI flame kernel data to find PI location E. Winklhofer, G. Fraidl, S. Eder 29 Juni

17 Test facility 2.1 Multi-cylinder engine test bed data decision Pre-ignition To understand it s root cause we need to see PI location. How to do so with a sporadic event located anywhere inside the combustion chamber? Use a multichannel (70 or 80 #) Visiolution sensor and synchronized master slave IndiCom operation with trigger on event capabilities to capture PI cycles E. Winklhofer, G. Fraidl, S. Eder 29 Juni

18 Test facility 2.1 Multi-cylinder engine test bed data decision Pre-ignition How would such pre-ignition show up in Visiolution flame data? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

19 Test facility 2.1 Multi-cylinder engine test bed data decision Pre-ignition How would such pre-ignition show up in Visiolution flame data? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

20 Test facility 2.1 Multi-cylinder engine test bed data decision Pre-ignition PI event detected in channel nr. 8. Flame kernel then expands into surrounding channels. Sensor channel orientation and flame kernel speed are used to locate PI event position PI cycle statistics show PI concentration in central part of combustion chamber near cylinder head. Potential root cause? Cylinder head temperature? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

21 Test facility 2.1 Multicylinder engine test bed data decision Pre-ignition Potential root cause? Cylinder head cooling? Test: late injection for charge cooling Decision: response to PI event with fuel rich and late multiple injection for a limited number of cycles to prevent engine from run-away PI cycles Benefit here: significant reduction of PI events by means of ECU response only. before after PI response ECU calibration for E. Winklhofer, G. Fraidl, S. Eder 29 Juni

22 Test facility 2.1 Multi-cylinder engine test bed data decision Soot (PN) sources M3 FL valve (&liner) wetting (different engine) The challenge: soot sources detection in high load and transient operation. Use the multichannel (70 or 80 #) Visiolution sensor as a high speed soot microscope. M4 FL premixed (central) E. Winklhofer, G. Fraidl, S. Eder 29 Juni

23 Channel number NORMAL ENGINE: HOW BEST TO LOCALIZE FLAME EVENTS IN SPACE AND TIME Soot (PN) sources Visiolution flame signal sensor spot on piston surface sensor Same data as above, color coded Polar plot of data for given crank angle Movie: flame 1 E. Winklhofer, G. Fraidl, S. Eder 29 Juni

24 Test facility 2.1 Multi-cylinder engine test bed data decision Soot (PN) sources Use soot microscope (80CH sensor) data to find injection strategies for critical transient and stationary operation modes in view of 1. Potential deposits formation 2. Forthcoming RDE test procedures E. Winklhofer, G. Fraidl, S. Eder 29 Juni

25 SOP - Start of production GDI ENGINE DEVELOPMENT SOME ACTIVITIES AND DECISION POINTS Engine development progress Simulation and components tests 1 Specification combustion system 2. Test the limits at normal engine operation in stationary and transient mode 1. Handover to thermodynamic (multicylinder) engine development Multi-cylinder engine development 2 Performance, emissions, durability 3. ECU calibration to comply with Euro 6c PN limit Vehicle testing ECU calibration driveability & emissions 3 months Which data do we need to conclude on correct decisions? E. Winklhofer, G. Fraidl, S. Eder 29 Juni

26 3.1 Chassis dyno Test facility data decision PN calibration Task: Find fuel injection parameters to safely pass the NEDC test for Euro 6c PN limit To do: Select rail pressure, injection timing, multiple injections at start, cat heating, warm up and transients to minimize PN contributions in the NEDC test The tools: PN tailpipe measurement and VisioFEM flame analyzer as a cycle by cycle guide for straight forward injection calibration for the entire 20 minutes test. E. Winklhofer, G. Fraidl, S. Eder 29 Juni

27 Test facility data decision PN calibration 3.1: Chassis dyno NEDC test shows need for local improvement E. Winklhofer, G. Fraidl, S. Eder 29 Juni

28 3.1 Chassis dyno Test facility data decision PN calibration 3.3 Result: final calibration meets development target PN tailpipe measurement before and after advanced calibration E. Winklhofer, G. Fraidl, S. Eder 29 Juni

29 SOP - Start of production SUMMARY TC GDI FLAME ANALYSIS TOOLS ALONG THE PROGRESS OF ENGINE DEVELOPMENT Engine development progress Summary Simulation and components tests 1 Specification combustion system GDI optical engine: Decision on injector and piston type Multicylinder engine development Performance, emissions, durability 2 Visiolution techniques: Knock: VisioKnock PN sources: VisioFEM gasoline Stability: VisioFlame Spray: Visioscope Vehicle testing ECU calibration driveability & emissions 3 months Chassis dyno, PN sources: VisioFEM gasoline The toolbox for engine development to support decisions on best functional modules (1), exploitation of modules degrees of freedom (2) and guidance to improve most relevant emissions issues to meet legislative targets (3) E. Winklhofer, G. Fraidl, S. Eder 29 Juni

30 THANK YOU