WLTP-09-20e_annex
Current status on a development of a Fuel
Economy Measurement Method considering the
Effect of Air Conditioner in Japan
14 January 2015
Japan
1
Background and Objective
WLTP-09-20e_annex
• Fuel economy (FE) of new vehicles has been improving
due to the fuel efficiency standard and car
manufacturer’s effort.
• However, it is well known that the gap between
official/catalogue FE and actual driving FE is still exist
due to Air Conditioner, Driving condition, Traffic
congestion, Maintenance, etc.
• In order to provide better information to car users, a
method for evaluating the A/C effect (one of the big
factors) on FE is highly required.
Japan, Ministry Land Infrastructure Transportation (MLIT),
intend to develop the method and procedure to evaluate
the FE under the A/C operation in the summer season.
2
Previous study (Test results using JC08)
WLTP-09-20e_annex
• Japan have been studying the effect of A/C use on Fuel economy in
the Japanese current test mode “JC08” driving mode.
• It was observed that the fuel economy was getting worse according to
increase of the specific enthalpy in the test cell.
• A good repeatability was obtained even if the dynamic driving mode
“JC08” was used.
• Questionnaire was done in order to investigate the actual A/C use in
Japan. (6,000 samples, Internet-based questionnaire)
Repeatability
MACTP-02-02e
MACTP-04-02e
Questionnaire
MACTP-04-02e
3
WLTP-09-20e_annex
Test Program in FY2013
 A/C tests were conducted in various conditions (ambient temperature
and humidity) using 2 vehicles in order to confirm whether the same
characteristics and good repeatability can be obtain or not, if WLTC
was applied instead of JC08.
• Vehicle A: 1.3L Petrol, CVT, Manual A/C, Idling stop system
• Vehicle B: 2.0L Petrol, CVT, Auto A/C, Idling stop system
• Test cycle： WLTC CL3-2 Phase1~3 (Low + Medium + High)
• Pre. conditioning: 60 km/h×30 min. with A/C operating
A/C setting / Vehicle condition
Vehicle ID
A/C type
A/C
Temp.
operation setting
A/C OFF
Veh.A
Manual A/C
A/C ON
Idle
23℃25℃28℃35℃stop(IS)
40%50%55%40%operation 40 kJ/kg 50 kJ/kg 61 kJ/kg 71 kJ/kg
Remark
(Test ID*)
Inlet
mode
Blower
level
Outlet
mode
(FRESH)
-
(FACE)
ON
-
●
-
-
Standard
LO (1/4)
FACE
ON
○
●
○
●
LFL - IS ON
MID (2/4)
FACE
ON
○
●
○
●
LFM - IS ON
LOWES
FRESH
T
A/C ON
LOWES
FRESH
T
A/C OFF
Veh.B
Auto A/C
-
Start
Environmental condition
Change A/C setting
-
(FRESH)
-
(FACE)
ON
-
●
-
-
Standard
22℃
AUTO
AUTO
AUTO
ON
○
●
○
●
22AA - IS ON
22℃
FRESH
MID (4/7)
FACE
ON
○
●
○
●
22FM - IS ON
25℃
AUTO
AUTO
AUTO
ON
○
●
○
●
25AA - IS ON
●：Number of test = 2, ○：Number of test = 1
*) Test ID: Temp. setting - Inlet mode - Blower level - IS Operation
Precon. 60km/h×30min
WLTC - LMH
Analyze
End
4
WLTP-09-20e_annex
Test results using WLTC
2.0
y = 0.024x - 0.3395
7.18
2.5
6.68
2.0
2
R = 0.9637
1.5
6.18
1.0
5.68
y = 0.0201x - 0.3137
R2 = 0.915
0.5
5.18
A/C OFF - IS ON
0.0
4.68
LFL - IS ON
Additional fuel consumption
(L/100km)
LFL: Lowest - FRESH - LO (1/4)
LFM: Lowest - FRESH - MID (2/4)
IS: Idling stop
Fuel consumption (L/100km)
Additional fuel consumption
(L/100km)
2.5
[ Auto A/C system ]
1.5
4.18
30
40
50
60
70
Specific enthalpy in the test cell (kJ/kg(DA))
80
10.0
9.5
y = 0.0176x - 0.2439
R2 = 0.7936
1.0
9.0
0.5
8.5
y = 0.0106x + 0.1452
2
R = 0.6844
0.0
LFM - IS ON
-0.5
10.5
22FM: 22℃ - FRESH - MID(4/7) y = 0.0339x - 0.2939
R2 = 0.9219
22AA: 22℃ - AUTO – AUTO
25AA: 25℃ - AUTO - AUTO
IS: Idling stop
A/C OFF - IS ON
22FM - IS ON
22AA - IS ON
25AA - IS ON
8.0
-0.5
Fuel consumption (L/100km)
[ Manual A/C system ]
7.5
30
40
50
60
70
Specific enthalpy in the test cell (kJ/kg(DA))
80
 The good repeatability on fuel consumption (less than 3%)
was also obtained when the WLTC was used.
 It was observed that the additional fuel consumption was
increased according to increase of specific enthalpy in the
test cell same as in JC08 driving mode.
5
Summary and Future plans
WLTP-09-20e_annex
 This method might be applicable to evaluate the
effect of air conditioner on fuel consumption.
 Japan plans to conduct further study in FY2014
Parameters
• Environmental condition
• A/C type (Manual/Auto)
• A/C setting (Blower level, Temp.
setting, inlet mode)
• Volume in a vehicle cabin
• etc
Actual data in use
• Representative environmental
condition by statistics
JPN Aug.: 30 degC, 60%RH, 71 kJ/kg
• Actual A/C use from questionnaire
• etc
Develop the test procedure with the WLTC
6