Flow Method

計測法詳細
Gravimetric Method
重量法
Principle： Weighing the H2 tank before and after the test
試験前後に水素タンクの重量を計測
その差から水素燃料の消費量を求める
W  g1  g 2
Here,
W = Fuel consumption
g1 = Mass of H2 tank before test , g2 = Mass of H2 tank after test
H2
H2
Precision
balance
Before and after the test
Advantages
FCS
Fuel bypass line
長所：水素の質量を直接測定（高い信頼性）
- H2 mass is directly measured (reliability).
Disadvantages
短所：水素タンクの着脱が必要
- Need to disconnect H2 tank from fuel line for weighing
1
Reference: JARI presentation
Test Equipment for Gravimetric Method
重量法の試験機器
Windshield
精密重量計
Fuel tank
Precision balance
Fuel tank setting device
- setting of a tank on the center of balance
- shock absorber for tank setting
重量計中央への設置、制振、風除け
Vibration-proof stand
Picture from JARI presentation
Precision Balance
A
B
Full scale
64100 g
64100 g
Minimum reading
0.1 g (approx. H2 1.0L)
0.01 g (approx. H2 0.1L)
Repeatability
0.1g *
0.025 g
Others
Windshield, Vibration-proof stand, Fuel tank setting device
Change of H2 mass(tens g) in H2 tank(tens kg) can be measured by
水素消費量(数十ｸﾞﾗﾑ)の計測可能
precision balance.
2
Consideration for Gravimetric method
考察
（重量法）
 Principle : Weighing a hydrogen tank before and
after a test - Simplest among 3 methods
最も実績のある、信頼できる方法
 Most proven and reliable method
精密重量計が入手可能
 Sufficiently precise balance is available.
Lﾌｪｰｽﾞの推定水素消費量(RCB=0)に対して精度を規定可能
 Measurement accuracy can be specified for
expected H2 consumption in L-phase of WLTC.
重量法を提案
JAMA proposes “Gravimetric method”
3
Pressure Method
圧力法
Principle： Measure pressure and temperature of H2 gas and
Derive mass of H2 from equation of state before and after a test
V
P
P2
W  m ( 1 
)
R z1  T1 z2  T2
Here,
試験前後に水素の圧力と温度を計測
状態方程式により水素重量を計算し
水素消費量を求める
W = Fuel consumption [g], m = Molecular weight of H2 2.016 [g/mol]
V = Volume of H2 tank [m3], R = Gas constant 8.314 [J/mol·K]
P1 = H2 pressure before test [Pa], P2 = H2 pressure after test [Pa]
T1 = H2 temperature before test [K], T2 = H2 temperature after test [K]
z1 = Compressibility factor at P1, T1, z2 = Compressibility factor at P2, T2
Advantages
- No need to disconnect
H2 tank 長所：水素タンクの着脱不要
Disadvantages
Pressure
gauge
Temp.
gauge
H2
- Difficult to measure H2 gas temp.
(Alternatively tank surface is measured)
短所：水素ガス温度把握が難しい
（代わりにタンク表面温度計測）
4
FCS
H2
Fuel bypass line
Reference: JARI presentation
Test Equipment for Pressure Method
Pressure gauge
圧力法の
試験機器
Temperature gauge
Range
0 to 16 MPa（abs）
Range
10 to 30 ℃
Error
0.05 %F.S.(8kPa)
Error
0.01 to 0.03 ℃
高圧測定可
 Applicable to high pressure
十分な精度
 Sufficient accuracy
十分な精度
 Sufficient accuracy
•
•
WLTC-L3(約3km)の水素消費を30gと想定すると
誤差8kPaは燃費の1%相当。誤差0.03℃は同0.15%相当
8kPa of error is equivalent to approx. 1 % of hydrogen consumption 30g.
0.03℃ of error is equivalent to approx. 0.15 % of hydrogen consumption 30g.
Condition: Tank Volume ：47L, Initial Pressure: 14MPa, Temperature: 23℃
30g of H2 consumption is assumed for phase-L3 of WLTC
5
Pictures/Tables from JARI presentation
Temperature Trend after Test
T1
T2
T3
T4
T5
T6
T7
Tank surface temperature[℃]
Tank Surface Temperature - during H2 gas discharge and soak
10cm
26
Discharge
T1
T2
T3
T4
T5
T6
V7
22
20
18
-20
0
20
40
60
Time [min]
Measurement Error after soak
80
Error of Pressure method [%]
Soak
•
The lower part reached lower temp.
than upper part.
•
Temp. increased again during soak.
・水素放出時にタンク温度低下
・ソーク時にタンク温度上昇（環境温度に戻る）
(reference: gravimetric method)
T1
T2
T3
T4
T5
T6
T7
0.5
0.0
-0.5
-1.0
60
Time [min]
80
•
Errors were reduced during soak.
•
Temp. at T4, T5 showed high accuracy
even in short soak time.
Soak after a test is needed to
eliminate error due to
temperature measurement.
-2.0
40
試験後のソークにより誤差が縮小
試験後のソークが必要（温度による誤差解消のため）
-1.5
20
Temp. decrease during H2 discharge
（H2 discharge : 30L/min, 5min）
100
2.0
0
•
16
ソーク後の計測誤差（重量法に対する）
1.0
タンク表面温度
（ガス放出およびソーク時）
Soak
24
47L tank
(Length 1350cm)
1.5
試験後のﾀﾝｸ温度
100
6
Reference : JARI presentation
Consideration of Pressure Method
考察(圧力法)
 Principle: Measure pressure and temperature of H2
tank. Calculate mass of hydrogen by using an equation
of state before and after a test.
重量法より容易な計測（適切に設定すれば）
 Easier to measure than gravimetric methods if setting
is provided appropriately.
高精度の圧力計が入手可能
 Sufficiently precise pressure gauge is available.
温度による誤差はソークにより解消可能
 Error due to temperature measurement is eliminated
by soak(at least 1 hour) after a test.
Lﾌｪｰｽﾞの想定水素消費量に対して精度を規定可能
 Measurement accuracy can be specified for expected
H2 consumption in phase-L of WLTC.
圧力法を提案
JAMA proposes “Pressure method”.
7
Flow Method
質量法
Principle： Measure H2 flow rate and Integrate during a test
W   q(t )dt 
test
Here,
m
22.414
水素燃料の流量を計測、積算し、水素消費量を求める
W = Fuel consumption [g]
= Integrated flow of hydrogen at normal conditions (273.15K, 101.3kPa) [L]
m = Molecular weight of hydrogen 2.016 [g/mol]
FCS
H2
Flow meter
H2 supply
ﾌｪｰｽﾞ間を連続して計測可能
Advantages
- Continuous measurement for series of phases
流量計、計測系の設定を事前に確認する必要がある
Disadvantages - Need to examine suitable flow meter and settings
for FCV test
8
Reference: JARI presentation
Verification of Flow Meter
Type
流量計の検証
Thermal
4~500
[NL/min]
Coriolis
10~750
[NL/min]
Volumetric
1.6~116
[L/min]
Ultrasonic
9~2000
[NL/min]
±1 [%FS]
±1.07 [%RD]
±2 [%RD]
(400~500NL/min)
±0.58 [%RD](500NL/min)
±0.66 [%RD](250NL/min)
±0.87 [%RD](100NL/min)
±4.49 [%RD](10NL/min)
Response
10 [ms]
－
－
50 [ms]
Pressure
Range
0~0.98
[MPaG]
0~10
[MPaG]
0~0.5
[MPaG]
0~1
[MPaG]
Range
Accuracy
(~400NL/min)
±2 [%FS]
(±0.2 [%RD])※1
Photo
[%FS] ：[% of Full Scale], [%RD] ：[% of Reading]
※1：In super highly accurate sensor use
9
Reference: JARI presentation
Characteristic of Flow Meter
流量計の特徴
精度とレスポンスを評価
 Accuracy and response of flow meters were tested in transient flow.
流量計により異なる結果（誤差は流量計の再補正により低減）
 Flow meters showed different trends and different integrated values. Those
errors were reduced by re-calibration of flow meters with sonic nozzle (JARI).
Flowrate [NL/min]
80
Coriolis
Sonic Nozzle
Error of Integrated flow [%]
T hermal
Volumetric
(Reference)
70
60
50
40
30
20
0
100
200
300
SampleT ime [sec]
6
4
2
0
Thermal
Coriolis
Volumetric
-2
-4
-6
400
Error of integrated flow
vs. gravimetric method
Trend data of instant flow rate
瞬時の流量の誤差
積算流量の誤差（重量法比）
10
Figures from JARI presentation
Issue of Flow Method - FCV test
流量法の課題
5車種のFCVの燃費を3つの方法で測定。一部のFCVでは流量法の誤差が大きかった
In 2004, fuel consumption of five FCVs were measured by three
methods , “Pressure”, ”Flow” and “Gravimetric(as reference)”.
Flow method showed large error for two FCVs.
流量法の誤差の大きさは
車両モデルに依存
Error range depends on vehicle model
Reference : JARI presentation
11
Application to FCV
車両への適用
車両に由来する誤差を解消するために流量変動の吸収の効果を評価
 Oscillation absorber was examined to reduce error relating to FCV.
Flowmeter
[Flow Method]
Regulator Silencer
Oscillation absorber
Test cycle
Test Number
Japanese 10-15mode, US HWFET, UDDS
2 in each test cycle
FCV
Vehicle that showed significant oscillations
in hydrogen flow
Flow meter
Thermal, Ultrasonic, Diff. pressure.
Pulsation absorber
Silencer (volume 4L), Regulator
Reference: JARI presentation
12
Error of Flow Method - FCV Test
流量法の
誤差
流量変動の吸収により誤差は減少
 Errors were reduced by using an oscillation absorber.
但し、流量変動の吸収の効果はWLTCで現在のFCVを用いた確認が必要
The effect of an oscillation absorber needs to be
examined with present FCVs in WLTC.
Figure from JARI presentation
Consideration of Flow method
考察（流量法）
原理：水素流量を計測し積算
 Principle: Measure H2 flow rate and Integrate
during a test.
計測系を適切に設定すれば、連続的な測定が可能
 If settings are provided appropriately, continuous
measurement is possible.
燃費の誤差は流量計、車両の燃料ｼｽﾃﾑ、試験ｻｲｸﾙに依存。幾つかの事例で変動吸収が有効
 Error depends on flow meter, FCV fuel system and
test cycle. Oscillation absorber was effective to
reduce error in some cases.
WLTCで現在のFCVを使った試験なしに、精度に関する規定を作ることは難しい
 Difficult to specify measurement accuracy without
testing present FCVs in WLTC.
JAMAはPhase 1bで流量法を提案しない
（試験データの裏付けある提案あれば反対しない）
JAMA doesn’t propose “Flow method” in phase 1b.
(Acceptable if proposed with test data in WLTC. )
14
Appendix
圧力法の補足データ
Supplement data for Pressure method
温度－ソーク時間
 Temperature / Soak time
 Error / Soak time
15
誤差－ソーク時間
Pressure容器試験前圧力
before discharge
Temp./ Soak time
8MPaG
放出終了
End
of discharge
26
26
24
24
24
22
22
22
20
18
16
14
容器表面温度[℃]
26
12
20
18
16
14
12
試験容器：SRL 104
10
0
20
40
60
80
100
-20
0
経過時間[min]
20
40
60
80
24
22
22
22
18
16
14
容器表面温度[℃]
26
24
20
20
18
16
14
12
試験容器：SRL 99
20
40
60
80
0
26
24
24
22
22
容器表面温度[℃]
26
20
18
16
14
20
40
60
80
100
0
20
40
試験容器：SRL 108
-20
0
20
40
60
経過時間[min]
Soak
time (min.)
20
18
16
14
試験室温度条件：25℃
Ambient
temperature: 25℃
試験容器：SRL 106
10
-20
14
T1
T2
T3
T4
T5
T6
T7
12
試験容器：SRL 106
10
60
経過時間[min]
Soak
time (min.)
80
100
100
16
End放出終了
of discharge
End
of discharge
放出終了
80
18
経過時間[min]
Soak
time (min.)
経過時間[min]
Soak
time (min.)
12
60
10
-20
100
40
20
12
試験容器：SRL 108
10
10
20
End
of discharge
放出終了
26
0
0
経過時間[min]
Soak
time (min.)
24
-20
試験容器：SRL 104
-20
100
End
of discharge
放出終了
容器表面温度[℃]
容器表面温度[℃]
14
26
12
ボンベ表面温度[℃]
16
経過時間[min]
Soak
time (min.)
End
of discharge
放出終了
100NL/min×5min
18
10
Soak time (min.)
200NL/min×5min
20
12
試験容器：SRL 109
10
-20
放出流量
5MPaG
End
of discharge
放出終了
End
of discharge
放出終了
容器表面温度[℃]
容器表面温度[℃]
50NL/min×5min
タンク温度／ソーク時間
14MPaG
タンク初期圧
-20
0
20
40
60
経過時間[min]
Soak
time (min.)
80
100
Data :Provided by JARI
16
80
100
Pressure容器試験前圧力
before discharge
5
試験容器：SRL 104
音速ノズルに対する誤差[%]
音速ノズルに対する誤差[%]
50NL/min×5min
5 min. soak
ソーク5分
2
1
0
-1
2
0
-1
-2
-3
20
30
40
50
5 min. soak
ソーク5分
1
-3
60
10
音速ノズルに対する誤差[%]
音速ノズルに対する誤差[%]
100NL/min×5min
40
50
4
ソーク5分
5 min. soak
2
1
0
0
40
50
ソーク5分
5 min. soak
1
0
-2
60
40
50
60
4
3
ソーク5分
5 min. soak
2
1
0
-1
-2
0
10
20
30
40
50
60
0
10
20
30
40
50
60
ソーク時間[min]
ソーク時間[min]
Soak time (min.)
6
30
試験容器：SRL 108
5
2
-1
20
6
3
-2
30
10
ソーク時間[min]
Soak
time (min.)
4
-1
20
0
-1
60
試験容器：SRL 108
Soak time (min.)
Soak time (min.)
6
試験容器：SRL 106
4
3
5 min. soak
ソーク5分
2
1
0
-1
T1
T2
T3
T4
T5
T6
T7
試験容器：SRL 106
5
音速ノズルに対する誤差[%]
5
音速ノズルに対する誤差[%]
30
5
ソーク時間[min]
200NL/min×5min
20
6
10
5 min. soak
ソーク5分
1
ソーク時間[min]
Soak
time (min.)
試験容器：SRL 99
0
2
-3
0
6
3
3
-2
ソーク時間[min]
Soak
time (min.)
5
試験容器：SRL 104
4
3
-2
10
5
試験容器：SRL 109
4
3
0
放出流量
5MPaG
音速ノズルに対する誤差[%]
5
4
燃費の誤差／ソーク時間
タンク初期圧
8MPaG
音速ノズルに対する誤差[%]
Error / Soak time
14MPaG
4
3
5 min. soak
ソーク5分
2
1
試験室温度条件：25℃
Ambient
temperature: 25℃
0
-1
-2
-2
0
10
20
30
40
50
ソーク時間[min]
Soak time (min.)
60
0
10
20
30
40
ソーク時間[min]
Soak
time (min.)
50
60
Data :Provided by JARI
17

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