12 v soc – monitoring - assessment of tolerances audi ag 8.11.2011 wltp-dtp-labprocice-105
TRANSCRIPT
12 V SoC – Monitoring - Assessment of Tolerances
Audi AG 8.11.2011
WLTP-DTP-LabProcICE-105
2 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Regulation R 101
► 5.3. Test results
► 5.3.1. The test results (fuel consumption C [l/100 km] and CO2-emission M [g/km]) of this test are corrected in function of the energy balance ΔEbatt of the vehicle’s battery.
► The corrected values (C0 [l/100 km] and M0 [g/km]) should correspond to a zero energy balance (ΔEbatt = 0), and are calculated using a correction coefficient determined by the manufacturer as defined below.
► …
► 5.3.1.1. The electricity balance Q [Ah], measured using the procedure specified in appendix 2 to this annex, is used as a measure of the difference in the vehicle battery’s energy content at the end of the cycle compared to the beginning of the cycle….
3 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Regulation R 101 (ctd)
► 5.3.2. Under the conditions below, it is allowed to take the uncorrected measured values C and M as the test results:
► 1) in case the manufacturer can prove that there is no relation between the energy balance and fuel consumption,
► 2) in case that ΔEbatt always corresponds to a battery charging,
► 3) in case that ΔEbatt always corresponds to a battery decharging
and ΔEbatt is within 1 per cent of the energy content of the
consumed fuel (consumed fuel meaning the total fuel consumption over 1 cycle).
► The change in battery energy content ΔEbatt can be calculated from
the measured electricity balance Q as follows:
► ΔEbatt = ΔSOC(%) ·ETEbatt ≅ 0.0036·|ΔAh|·Vbatt = 0.0036·Q·Vbatt (MJ)
► with ETEbatt [MJ] the total energy storage capacity of the battery and
Vbatt [V] the nominal battery voltage.
4 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Regulation R 101 (ctd)
► 5.3.3. Fuel consumption correction coefficient (Kfuel) defined by
the manufacturer
► 5.3.3.1. The fuel consumption correction coefficient (Kfuel) shall
be determined from a set of n measurements performed by the manufacturer. This set should contain at least one measurement with Qi < 0 and at least one with Qj > 0.
► …..
► …..
5 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Equipment for Monitoring of SoC
0,1% rdg and 0,2% f.s. 0,5% rdg and 0,05% f.s.
rdg accuracy (0,12+0,52) = 0,51 %f.s. accuracy (0,22+0,052) = 0,21 %
f.s. = full scalerdg = readingError depends on full
scale and actual values
6 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Theoretical approach – 200 A over NEDC
0
10
20
30
40
50
60
70
80
-200
-150
-100
-50
0
50
100
150
200
0 200 400 600 800 1000 1200
current [A] electrical charge [Ah] charge ± tolerance [Ah]
[A]
[Ah]
[t]
error = ±0.72 %
Max dev. = 0.48 AhCurrent constant @ 200 A
7 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Theoretical approach – instationary test, 3 Ah over NEDC
Max dev = 0.16 Ah
(In WLTC ~ 5 Ah corresponds to Ebatt = 1% Energy of consumed fuel @ ~100 g/km CO2)
-5
-4
-3
-2
-1
0
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5
-200
-150
-100
-50
0
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100
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0 200 400 600 800 1000 1200
current [A] electrical charge [Ah] charge ± tolerance [Ah]
[A]
[Ah]
[t]
error = ±6 %
8 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Tolerance of CO2-Measurement
► The error in the determination of CO2 is a result of tolerances in various systems within the
complete emission test procedure:
► Tolerance of measurement equipment
• Span Gas
• Linearization of Analyzer
• Span Gas Divider
• Dyno specifications (tolerances)
► Tolerance of vehicle (e.g.)
• Battery energy management
(charging/decharging)
• Operational strategies (adaptions etc.)
• Reference fuel (density)
► Tolerance of lab processes
• Speed trace – shifting points
• Soak temperature
With improved WLTP procedures and reduced tolerances an overall tolerance of 2 % in CO2 measurement is estimated.
Results of Validation Phase 2 and Correlation will provide further evidence
9 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Assessment of Tolerances for Correction of CO2 as f(SoC)
0 Ah+10 Ah - 10 Ah - 5 Ah+ 5 Ah
100
95
90
105
CO2
g/km
Delta SoC 12 V Battery
Vehicle with Turbo Diesel Engine FC 3,8 l/100 km = 100 g/km CO2
Test Cycle: WLTC Battery Voltage: 12.8 V Tolerance CO2 Measurement: 2 % Tolerance SoC Monitoring: 6 %
Meas. Tolerance of CO2
and SoC
Function of CO2 vs. SoC =>
1,6 g CO2 per Ebatt /% of consumed fuel
Evaluation of CO2/SoC ratio with tolerances (R101)
=>max 2,6 g/km CO2 / Ebatt
min 0,6 g/km CO2 / Ebatt
Ebatt= +-1% of consumed fuel
Ebatt= +-2% of consumed fuel
Application of R101 provision
10 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Conclusion
► The error in the determination of electrical charge with an typical ammeter consists of full scale and reading error. For a typical current of a conventional engine it is assessed at 6 %. The error in the determination of CO2 is estimated at
minimum 2 % over the whole chain of measurement equipment, vehicle and lab process.
► For a vehicle emitting 100 g/km CO2 in WLTC Cycle, Ebatt of 1 % of consumed fuel
energy is about 5 Ah. The tolerance of measured energy - depending on charging
strategy - is about 0.3 Ah.
► For correction of CO2 following R101 the ratio measurements at different Ebatt of
the low voltage batteries have to be performed (feasibility of this proposal for low voltage batteries is still to be evaluated)
► The assessed tolerances of CO2 and SoC measurement result in an overall
tolerance in the determination of the ratio CO2 / Ebatt of about 60 %.
► The correction process for CO2 as f(Ebatt) for a low voltage
battery is still very much uncertain. Further data have to be provided through VP2
11 Dr. F. Mühlberger, Dr. M. Bergmann, Dr. Kolesa AUDI AG
Proposal
Options:
► Make no proposal from OICA (Tuev Nord proposed following R101)
► Apply R101, but stay with a correction threshold of Ebatt
> 2 % of consumed fuel energy for low voltage batteries monitoring. Further evidence will be available after Validation Phase 2 and WLTP Correlation.
► Use of a fix correction function dependent on used battery energy (1 % of consumed fuel energy = 1,6 g/km CO2) without threshold.
…..