MAC Pilot Test Phase. 4 th Stakeholder meeting. December 17 th, 2012 Brussels

Transcription

1 1 4 th Stakeholder meeting December 17 th, 2012 Brussels TUG: Stefan Hausberger, Werner Stadlhofer LAT: Zissis Samaras, Savas Geivanidis TNO: Robin Vermeulen, Willar Vonk

2 Contents Consortium of TUG, LAT and TNO 2 10:00 Welcome Steininger 10:15 0) Introduction (TUG) TUG 1) Results from pilot phase A, main open topics: 1.1) SOC based correction of FC, based on average alternator efficiency etc. TUG 1.2) Mass flow measurement method - discussion: how to handle recirculating air TUG, ACEA mode? 1.3) Reconsidering correction factors, especially P-factor TUG, LAT 1.4) Definition of humidity in MAC test - change from relative to absolute humidity ACEA, LAT 1.5) Bag measurements in the MAC test LAT, ACEA 1.6) Correction factor for Vehicle size classes - mass flow adaptation or correction TUG factor vs. vehicle 1.7) Family definition TNO 1.8) Technical annex TNO 12:30 Lunch brake 13:30 2) Results from the round robin test + Discussion LAT 14:30 3) Presentations/Discussion of experiences with the MAC test Suggestions for improvements and modifications 15:00 4) Other open topics: 4.1) Effect of MAC deactivation < 18 C if above dew point 4.2) Correction for glazing size and quality: agreed on method ACEA, Others? 16:00 5) Conclusions: list of open topics and responsibilities TNO 17:00 End of meeting JRC TUG ACEA, Glass for Europe

3 3 INTRODUCTION contains two test phases: WP100 Programme definition, preparation Identify procedure improvement possibilities Prepare simple test elaboration tool Process comments from stakeholder meeting WP210 Phase A Multi-lab Pilot test phase-a (improve procedure and cover open issues) ~ 11 labs WP310 Data review Procedure evaluation to draft final + Open tasks from phase-a Stakeholder comments and learning points WP230 Phase B Multi-lab Round Robin test phase-b with golden vehicle (reproducibility, sensitivity and repeatability) 5 labs Current status WP310 WP400 Data review Procedure evaluation to final procedure Write technical annex to regulation (incl. reviews) Stakeholder comments and learning points

4 4 Time Schedule of the Pilot Test Phase Project started 16 August Month WP 100 Definition, preparation 200 Phase A pilot testing Phase B round-robin Finished 10/12/ Procedure review Still ongoing 400 Annex compilation 500 Management Current status

5 5 Round Robin: main open topics 1.1) Correction factor for electric energy flow Energy is stored and released in the battery. This energy is provided via alternator by the engine influence on instantaneous fuel flow. Accurate correction needs high effort since Efficiency of the alternator depends on rpm and Current Efficiency of the battery loading depends on SOC and temperature Efficiency of the engine depends on load and rpm Certainly all efficiencies depend on make and model Accurate correction needs component testing + detailed simulation! First simplified approach based on generic data is developed. Simplified approach is based on Willans Line approach (similar to alternative P-Factor method discussed last meeting)

6 6 1.1) Correction factor for electric energy flow Willans line from MAC tests in Phase A (8 vehicles included) FC [g/s] = * Pe Additional FC due to additional useful power Friction losses Incremental change in engine power demand in MAC-test FC [g/s] = 0.07 * Pe

7 7 1.1) Correction factor for electric energy flow FC [g/s] = 0.07 * Pe per kw additional engine power demand Electric power from or to battery: P el = (U * I) * [kw] Ranges found for the 6 MAC phases from -60 to +50 A at ~12.5 V worst case may be -1 kw < P el < 1 kw at η el > 50% Power generation on average up to 2 kw P e correction up to [g/s] Electric power from battery: correction up to [g/s] Phase Fuel flow MAC-off [g/s] Possible influence from alternator weighting factor Idling % 15% 50 km/h % 65% 100 km/h % 20 MAC-test % 100% +34% > 2x influence from MAC!

8 8 1.1) Correction factor for electric energy flow Simple correction could reduce problem but still a high uncertainty remains (is alternator efficiency 50% or 90% for specific vehicle?) Also a limitation in maximum unbalanced electric energy flow for a valid test is necessary To limit the unbalanced electric energy flow a reasonable option seems to be to connect the battery over the entire MAC test to a battery charger with reasonable Voltage to level eventual alternator controller effects out! This would set the relevant power demand from the alternator to the engine to constant idling demand and should eliminate the problem (almost) completely. Correction for unbalanced electric energy may not be necessary -- But this method can not measure electric driven devices, such as the HVAC blower or electric driven compressors Discussion and comments from ACEA on this proposal necessary! We may need to test this approach (small RR test TUG +??) Take a gasoline vehicle this time to prevent DPF regeneration effects?

9 9 1.1) Correction factor for electric energy flow If still necessary, following correction is suggested: P ( I U ) [kw] el i = Phase i Phase i Relevant for Engine power only if Pel-i > 0 (i.e. loading of battery via alternator) if ( P el 0, P = 0) FC i Current < el i = (0.15 ( P P ) ( P P ) 1 η ( P P )) el 3 el6 el 1 Engine el 4 el 2 Application for TUG tests in phase B: el 5 unit [kg/h], FC needs to be subtracted from the measured MAC-FC + Remark after meeting: Pel <0 should also be corrected accordingly to take energy consumption from electric devices into consideration Test after DPF regeneration

10 10 1.3) Mass flow measurements and settings 1) Connect auxiliary blower to cabin. Vary mass flow, record pressure difference. Draw diagram: 2) Vary HVAC setting, record pressure difference. Read corresponding mass flow from diagram from step 1. Works well. Problem occurs, if recirculation air is used later in MAC-test since test procedure gives p for fresh air mode only!

11 11 1.3) Mass flow measurements and settings Options to solve the problem: Measure vent outlet flow velocity (anemometer) Define that velocity at each vent has to be higher than in basic mass flow test. If relevant correct for Temperature (vent outlet) and pressure (cabin) Ideal gas equation: m& = p V& R T Assuming volume flow as proportional to vent outlet velocity: m& m& MAC i = v MAC v i T T i MAC p MAC vmac Ti pmac m& MAC = mi > 230kg / h v T p i MAC p i i v. Velocity [m/h] T..Temperature [K] p pressure [pa] i.measured in HVAC setting conditions (fresh air) MAC...measured at MAC test To be discussed: where locate anemometer? Temperature sensor already mounted in centre! Make separate mass flow evaluation tests (need no chassis dyno),..

12 12 1.3) Reconsidering correction factors, especially P-factor Incremental change in engine power demand in MAC-test (from slide 5) Simple correction possible: FC [g/s] = 0.07 * Pe [kw] Fuel flow at MAC-Off phases is corrected to the power of the corresponding MAC-On phase FC corr_mac-off_phase_i = FC MAC-Off_phase_i + (P MAC_on_phase_i - P MAC_off_phase_i ) * 0.07 [g/s] Similar to last version of incremental fuel consumption based method, but simpler formula Relevance of Power correction: < 0.1 kw difference found in phase B: 0.1 * 0.07*3.6 = kg/h i.e. up to 10% of MAC FC

13 13 1.6) Correction factor for vehicle size classes (1/5) Application of C size : I) simple correction factor for MAC fuel consumption measured at 230 kg/h mass flow: FC = C MAC size FC MAC T II) correct mass flow in test procedure m& C 230 = size Both options can be kept in parallel: I) apply when small deviations in size reduce test burden II) Apply when the 230 kg/h lead to untypical MAC operating point Two basic options to define C size : a) Proportional to cabin volume maintain flow velocity in cabin on same level for all vehicle sizes b) Consider also energy balance in cabin rather relevant, if recirculated air is used, then cooling capacity is proportional to heat entrance into cabin In the following a calculation for b) is shown and results are compared to a)

14 14 Round Robin: main open topics 1.6) Correction factor for Vehicle size classes (2/5). Energy balance cabin: m dt air int cabin air c p air + mint erior c = mmac c p air dδ = zero at steady state conditions (i.e. after preconditioning phase) dt dδ ( tv tout ) + Q& cabin Q& glazing & + 0 = m MAC cp air Conservation of mass: m & MAC = m& out i ( tv tout ) + Q& cabin Q& glazing & + m& MAC = Q& c cabin p air + Q& cabin + Q& glazing ( t t ) 1 ( 21 15) out glazing v Q& MAC ( Q& Q& ) 1 m & = + 6 cabin glazing Already considered by correction factor (F TTS )

15 15 1.6) Correction factor for Vehicle size classes (3/5). MAC ( Q& Q& ) 1 m & = + 6 cabin glazing m& m& MAC MAC avg. Q& Q& cabin cabin avg + Q& + Q& glazing avg glazing avg = C size Values to be defined: Q glazing-avg = 530 W (per definition FTTS = 1.0 for 530 W heat entrance through glazing at 700W/m² sun radiation) Q cabin depends on: temperature gradient, air flow (α i ), size and material of the body and insulation (A, d, λ). Simplified calculation via heat transfer coefficient (k) Q& cabin = k A ( t t ) ambient cabin with 1 k = 1/ α + d / λ + 1/ α i K set const. = 3.1 (i.e. independent from size class) a Q& cabin = k A ( t t ) ambient cabin m& m& MAC (3.1 A 4) = (3.1 A 4) 530 MAC. Avg. + Avg

16 16 1.6) Correction factor for Vehicle size classes (4/5). Simple definition of area A relevant for heat transfer (= without glazing). Draft: A cabin = L x B + L x H x B x H Option b): C size Area = Q& Q& Avg. m& m& MAC MAC Avg. = ( L B + L H B H) H Source: L B Option a): C size V = m& m& avg. V V cabin avg L B H 0.35 ( L B H ) Avg L B H V.volume of the cabin = kv * L*B*H

17 17 1.6) Correction factor for Vehicle size classes (5/5). Application for some models (results using option b) Comparison of options a) and b) To be discussed: Results option b) indicate, why no correlation was found in phase A between size and cabin temperature (all vehicles tested with 230 kg/h) However, which option to select? Weighted average according to % recirculated air? If yes, how to determine % recirculated air? Simple approach: take option a) C Size-V

18 18 1,7 and 1,8) Considerations for a family definition to be used for the selection of M1 vehicles to be tested over the MAC procedure Stakeholder workshop Brussels, 17 December 2012 Robin Vermeulen

19 19 Starting points Main goal of family definition is to minimize test burden: in the case of MAC an explosion of the number of tests would occur by just adding a dimension (MAC system) to the existing test matrix. At the same time maintain the desired discriminative power of the procedure. The purpose of the procedure is to be able to distinguish MAC systems with regard to efficiency. Scope of a family should be adjusted to the accuracy of the procedure. Three sub systems: 1. MAC + propulsion 2. Powertrain: engine + transmission 3. Vehicle cabin + glazing

20 20 Approach: Worst case: Add MAC types to the current t-v-v matrix. Classification based on technical MAC characteristics with significant influence on dfc. Additional tests per t-v-v for different MAC types. Number of tests increases dramatically. Test the worst variant based on technical characteristics. Proposal is to look for solutions to reduce the number of tests hereby not sacrificing discriminative power: clustering of vehicle types with expected similar behavior. modeling the influence of some variables. This leads to test values for the parent and vehicles with similar properties and declared values for vehicles of which dfc is determined indirectly.

21 21 Resulting tasks To define the properties which: do not influence the dfc and can be clustered do influence the dfc and need fragmentation do influence the dfc and can be modelled (and maybe clustered or fragmented)

22 22 Sub systems: 1 MAC Examples of technological variables that may influence dfc are: Compressor type, capacity Heat exchangers number, size and efficiency Expansion valve: type and control Control: Recirculation, compressor control (on/off), more.. Cooling medium Transmission ratio of compressor propulsion # of cooling circuits Type of compressor propulsion (electric, combustion engine) Others? Q to the stakeholders: information is needed about the variation of MAC systems within current vehicle types. How do the systems differ with regard to the features that influence dfc. Which features should be regarded?

23 23 Sub systems: 2 powertrain Combustion type (SI, CI) / Fuel type Power Type of powertrain (ICEV, HEV, EV) Gear box, transmission (gears, differential and wheel diameter). # driven wheels Cluster engine types: Yes. Influence on delta FC is low (1-2% of dfc). Where to put the line? Fuel, Power, CI, SI? Cluster 4WD 2WD. Yes. Q to stakeholders; what can be clustered and to what extend? Does transmission ratio influence dfc? Are there other features of types and variants which should be regarded?

24 24 Sub systems: 3 cabin Size (correction possible) Glazing; surface and heat transmission (correction possible) Insulation, heat conductivity body panels (unknown.) This is generalized in current correction method (Average effect is taken into account). Q to the stakeholders. Others to take into account? Is the current t-v-v definition suitable? Or should body and glazing variants be added? Probably depends on current body and glazing variation existing within t-v-v approach.

25 25 2) Results from the round robin tests + discussion Contents Introduction to the Round Robin test campaign Overview of the tests Data corrections and fuel consumption results Effects of test parameters on results Issues raised during testing Discussion and suggestions

26 26 Round Robin test campaign identity Golden vehicle: BMW 318d Touring, diesel Euro 5, 1995 cc, 6 gear Monitoring: Participants: Test: Repetitions: Reference engineer on-site preparation day and 1 test day 5 laboratories, industry and independent: A, B, C, D, E MAC test (after vehicle soaking) 24 tests (~50% valid) Measurements: CO 2, FC, modal or (and) bags, cabin temperatures, pressure, current and voltage: battery, AC blower, alternator

27 27 The MAC test cycle MAC status Speed Description MAC ON 90 km/h MAC ON MAC OFF Start [s] End [s] Result to be measured: FC in [kg/h] Method of measurement Weighing factor/phase Result calculated for each of the two phases by weghing subphase data in [kg/h] Adjust T setting to T vent <15 C Stabilize at preconditioning speed km/h (idle) idle FC i-mac modal data (or bag 1) 15% 50 km/h low speed FC 50-MAC modal data (or bag 2) 65% 100 km/h high speed FC 100-MAC modal data (or bag 3) 20% 0 km/h idle FC i modal data (or bag 4) 15% 50 km/h low speed FC 50 modal data (or bag 5) 65% 100 km/h (idle) high speed FC 100 modal data (or bag 6) 20% FC MAC-on FC MAC-off

28 28 MAC test specifications Soaking on the day before measurement: Duration >8 h Temperature 25 ± 2 C Conditions during test: Relative humidity φ a = 45% ± 5% Absolute humidity x = 8.9 g/kg ± 1 g/kg Temperature T a = 25 C ± 2 C Vent out. temperature T vi < 15 C Air mass flow m a > 230 kg/h Gear shifting as described in MAC cycle Solar load simulation no Speed as described in MAC cycle

29 29 Regeneration during measurement, data handling Calculation areas were adapted to remove problematic areas

30 30 Overview of Round Robin tests valid corrected and considered valid not valid Lab. Test ID Regener. MAC on MAC off Start stop idle 50 km/h 100 km/h idle 50 km/h 100 check beg end beg end beg end beg end beg end beg end beg end beg end Other critical issues A1 valid A A2 valid hot start A3 valid hot start A4 valid B1 valid hot start B2 B B3 valid B4 valid B5 valid B6 valid C1 stratification: top C C2 C3 valid C4 D1 valid D D2 valid D3 Temperature setting failure D4 Temperature setting failure E1 hot start, analogue ch stuck E2 valid E E3 E4 E5 E6

31 31 Correction factors (1,3) Description Description MAC FC uncorrected MAC FC uncorrected (differencefc MAC on -FC MAC off ) (1) TA (Power, Tcell, RHcell) The basic result proposed for Type-Approval. Corrected for power, for temperature and humidity in the test cell (according to polynomial equations in report) but not for vent outlet temperature. (2) = (1) & Tvent_average As (1) but corrected also for measured vent outlet temperatures. For the correction factor the average of all vent outlet temperaturesin the corresponding period is used.

32 32 Valid test results and correction No battery charge effect - low T vent - battery charging (not connected to charger during soaking) - battery charging Average of max T vent [ C]: Battery effect is negligible in most cases (as long as vehicle is left on charger during soaking) T vent correction works towards the correct direction

33 33 Vehicle load As expected no variation between MAC on and MAC off phase Significant difference of vehicle load at lab. A (definition of P) Groups of labs may match due to common type (maker) of dyno

34 Ambient conditions control (1,4) Accurate control Consortium of TUG, LAT and TNO More unstable control 34 Absolute humidity control Tests are within specifications as regards ambient conditions (specifications are achievable by normal test facilities) Any variation of ambient conditions is reflected to the vent outlet temperature Alternative absolute humidity specifications do not correspond 1:1 to relative humidity specifications

35 35 Absolute and relative humidity control (1,4) Absolute humidity limits do not directly correspond to relative humidity ones Only one lab. uses absolute humidity as reference and controls well both

36 36 Data correlations explored No observable correlation of fuel consumption to vehicle operation or ambient air conditions

37 37 Overview of test results (all corrections) outlier Mean value of all labs: In-lab max variability: ±7% kg/h

38 38 Repeatability of the test? Data from two consecutive days Same MAC setting (blower stage 4, 19.5 C)

39 39 Issues raised during the Round Robin campaign Regeneration of DPF (due to long steady state operation points) Start & stop system activation MAC system may occasionally behave abnormally (e.g. require different settings at the same lab and test conditions just in one test) Additional MAC settings not covered by current test procedure (e.g. air stratification at front vents) Different versions of the MAC cycle available Duration of the test higher than any other type-approval test Cold start requirement does not allow multiple tests per day Methodology of CO 2, FC measurement (modal, bag, timing, other?) Methodology of current flow measurement

40 40 Summary and suggestions The test is repeatable: Given that the MAC system operates consistently At current timing of test phases (effect of change in timing not known) A shorter vehicle soaking period may be considered (e.g. 3-4 hours windows open) to allow more tests in one day Round robin data should be looked into more detail to verify consistency of measured quantities to reveal drifts and inaccuracies and possibly make additions for quantities to be measured in the main test procedure

41 41 Fuel consumption measurement methods (1,5) Method Advantages Disadvantages Instantaneous Possibility of detection of even short inconsistencies 6 bags Simple, physical integration of emissions < 6 bags with pauses to analyze bags between phases < 6 bags rotating through (analysis of previous bag during test to be reused after the next bag is filled) 1 bag for MAC ON + 1 bag for MAC off, sample gas proportional to test weighing factors No investment No significant investment (?) No investment Need equipment to continuously monitor emissions Investment needed (6 bags for exhaust + 6 bags for ambient, may reduce latter) Unknown effect of pauses to test results Need dedicated set of analyzers and adaptation of chassis dyno automation Need of adaptation of chassis dyno automation, now way to diagnose sub-phase to subphase inconsistencies

42 42 Other open topics 4.1) Effect of MAC deactivation < 18 C if above dew point (TUG) Background: MAC shall be deactivated at temperature below 18 C as long as no fogging of windows or other security risks occur. This options shall be awarded by a bonus factor Simulation of fuel saving potential and of reasonable test conditions H2O vapour from ambient (test cell) and from passengers per kg dry air have to Lead to relative humidity in vehicle cabin <1.0 m vap-driver m dry_air m dry_air m vap-1 m vap-2 m vap m 1 = m dry_air + m vap-1 m 2 = m dry_air + m vap-2 + m vap-driver

43 43 4.1) Effect of MAC deactivation < 18 C if above dew point (TUG) Assessment of total CO2 reduction potential:: 1. Assumption: today not active below 5 C 2. Simulate MAC fuel consumption for each hour > 5 C for Athens, Frankfurt, Helsinki 3. Simulate MAC fuel consumption for each hour 5 C < t < 18 C when RH in cabin <1.0 for Athens, Frankfurt, Helsinki 4. Make ratio from result 3./4. = reduction potential if all MAC systems would be deactivated below 18 C when below the dew point. The simulation tool developed in the first phase of the MAC project was applied, calibrated for modern MAC systems (simulate future CO2 reduction potential). Tool gives 0.24 kg/h MAC fuel cons. when the MAC test procedure is simulated with 230 kg/h mass flow. Weather data and traffic volumes used as elaborated in first MAC phase (Hausberger, 2010)

44 44 4.1) Effect of MAC deactivation < 18 C if above dew point (TUG) Weather conditions (also hourly traffic volumes are in the data set shares of hours >5 C Hours 5 C < t < 18 C with RH<1 Are calculated as shares in traffic volume, not in time (less traffic in night hours) Athens Helsinki Frankfurt ATH FRANKF HELSINKI % hours 48.1% 51.8% 40.5% % traffic 45.1% 51.3% 41.8%

45 45 4.1) Effect of MAC deactivation < 18 C if above dew point (TUG) Result: approx. 25% of MAC fuel consumption could be saved (i.e. roughly 0.3% from CO 2 emissions from passenger car sector) Running hours / car MAC consumption MAC fuel consumption in stable conditions Condition: All >5 C 5 C<t<18 C, RH<1 >5 C 5 C<t<18 C, RH<1 Reduction Area [h/year] [kg/year*car] [kg/year*car] [Mio. tons/year] [%] Hot % Average % Cold % Total % Test procedure (draft): soaking for at least 4 hours at a t < 18 C, 50% < RH< figure Start vehicle, drive any test (chassis dyno NEDC or WLTC or real world) MAC compressor not active in automatic setting bonus Test met between 15 C and 18 C Bonus = -20% Test met between 10 C and 15 C Bonus = -10%

46 46 5) List of actions from this meeting Questions and actions for EC consultants (1/2) Definition humidity; absolute or relative Settings needed for the air stratification at vent outlet. Cold start requirement makes repetitions unpractical. For repetitions warm start allowed. Criteria needed for time between tests. Define number of test repetitions. Minimum number of tests of 3 if within tolerance (for instance standard deviation), additional tests required to get within tolerance. This requires a tolerance setting. Statistical elaboration of test data needed to determine the tolerance. FC measurement method; amount of bags may be limited Investigate to allow options within procedure to decrease conditioning phase length to 3-4 hours.

47 47 5) List of actions from this meeting Questions and actions for EC consultants (2/2) Electric energy consumption: few options Limit unbalance (SOC). Outside margin, test not valid. Connect battery charger during test. Not preferable. Electric energy 20-40% of total MAC energy. 2 step approach within limits (tolerances needed like +/- 5%), outside limits optionally correct Improved correlation function vehicle specific FC =f(de); (50 km/h test) to improve function Define cabin size correction, as function of vehicle size. Other standards for determination of cabin size exist but do not improve correlation. Limit Recirculation air amount and a way to check this (for the requirement of minimum amount fresh air in cabin).

48 48 5) List of actions from this meeting Questions and actions for ACEA What affects the MAC control and is not in the current procedure? Any new ideas to deal with consumption of electric power by MAC. Provision for MAC deactivation feature check, to be put in the concise methodology description. This can be integrated in the annex. Also needs a description of conditioning. Provide Willans lines and a method to determine them. Family definition: Criteria for family classification. What to cluster and what to fragment? What and how many types of MAC platforms can be identified across a vehicle type and how are they identified.

49 49 Thank you for your attention Stefan Hausberger Savas Geivanidis Robin Vermeulen