1. UN-R41.04 ASEP
Overview

2. ASEP overview ◆Overview of the regulation ◆Reference point
To assess the amount of change in WOT noise relative to the engine speed.
The criterion are below the linear slope of 5 dB/1,000 rpm for higher engine speeds and 0* dB/ 1,000 rpm for lower engine speeds in relation to the reference point +3 dB.
The regulation applies to Class III (PMR>50) only.
◆Reference point
　-The same as Lwot at the time of measuring Lurban (in case of measurement using the two gears, select the one for the lower gear).
0　Engine revolutions in front of microphone nPP’
Full-throttle noise value dB
Reference point
Upper
limit point
Regulatory value
3dB
Lower limit point
5dB/1000rpm slope
0dB/1000rpm slope
Test result image
<Non-conformance area>
<Conformance area>
(*1dB from 2017) P P' B B' A A'
Microphones
(Throttle fully closed)
(Wide open throttle)
Test course overview

3. ASEP overview ◆Upper limit point
　- The vehicle speed nAA’ at point AA’ is adjusted so that the engine speed nBB’ at point BB’ could satisfy the below and WOT noise level is measured.
　　nBB’=0.85×（ｓ-nidle）+nidle　(PMR≤66)
　　nBB’=3.4×PMR-0.33（ｓ-nidle）+nidle　(PMR>66)
　　The selected gear shall be 2nd. If the 3rd gear satisfies requirements of nBB' and vBB', 3rd shall be used. If the 4th gear satisfies requirements of nBB' and vBB', 4th shall be used.
0　Engine revolutions in front of microphone nPP’
Full-throttle noise value dB
Reference point
Upper
limit point
Regulatory value
3dB
Lower limit point
5dB/1000rpm slope
0dB/1000rpm slope
Test result image
<Non-conformance area>
<Conformance area>
(However, VBB’≤80km/h)
s: rated engine speed
nidle: Enging speed at idle P P' B B' A A'
Microphones
(Throttle fully closed)
(Wide open throttle)
Test course overview
◆Lower limit point
　- The vehicle speed VAA’ is adjusted so that the engine speed nAA’ at point AA’ could satisfy the below the WOT noise level is measured.
　　nAA’=0.1×（s-nidle）+nidle　　(However, VAA’≧20km/h)
　　No specification of gear selection for the measurement.

4. ASEP overview ◆Evaluation method of the final result
0　Engine revolutions in front of microphone nPP’
Full-throttle noise value dB
Reference point
Upper
limit point
Regulatory value
3dB
Lower limit point
5dB/1000rpm slope
0dB/1000rpm slope
Test result image
<Non-conformance area>
<Conformance area>
◆Evaluation method of the final result
　- Noise value is plotted against engine speed in front of microphone nPP’.
　- Measurement is required at least for the reference and upper limit points; Additional test points are allowed.
　- Criteria must be met at all points within the range from lower to upper ASEP limit lines.
　- If the change of nBB’ is limited to less than 0.05×（ｓ－nidle) against the reference point, the ASEP does not apply (in case of some CVT vehicles). P P' B B' A A'
Microphones
(Throttle fully closed)
(Wide open throttle)
Test course overview

5. ASEP control range ASEP control range Example 1st 2nd 3rd 4th 5th
vBB' < 80 km/h
nBB' < 0.85 * (S - nidle) + nidle (PMR < 66)
　　　 3.4 * PMR * (S - nidle) + nidle (PMR > 66)
1st
2nd
3rd
4th
5th
ASEP control range
nAA' > 0.1 * (S - nidle) + nidle
vAA' > 20 km/h
#/n

6. Limit (shown by the graph)
Example
Line with slope of 5dB/1000min-1
Line with slope of 1dB/1000min-1 *
3dB
Lwot,(i)
Reference point
full throttle acceleration test
･vPP’ = 50km/h
･the same gear(i) as tested
in Annex3
Any measurements shall be within this area.
nwot,(i)
* 0dB/1000min-1 until the end of 2016
#/n

7. Example of ASEP measurement

8. Example of ASEP measurement
G vehicle: MT model
Maximum output=29kW; vehicle weight=168 kg; PMR＝119.3; ｓ＝14000rpm; nidle＝1600rpm
Desk study results of test conditions
Gear
Upper limit point
Lower limit point
nBB’＝10300rpm
nAA’＝2840rpm
VBB’（km/h）
VAA’（km/h）
2nd
61.8
17.0
3rd
77.7
21.4
4th
93.8
25.9
◆Reference point
　Third gear VPP’=50km/h (Lurban: Measured with third gear)
◆Upper limit point
　nBB’=3.4×PMR-0.33（ｓ-nidle）+nidle　=10300
　VBB’≦80km/h
◆Lower limit point
　nAA’=0.1×（ｓ-nidle）+nidle　=2840
　VAA’≧20km/h
It is expected that 3rd gear will be employed for the upper limit measurement and 4th gear for the lower limit.
Reference point test result
Gear L R
VAA’
VPP’
VBB’
nPP’
3rd 1
76.1
77.6
41.9
50.1
57.4
6589 2
76.8
42.4
50.7
58.1
6668 3
76.7
77.2
40.5
49.2
57.0
6471
Average
76.5
41.6
50.0
57.5
6576
Final test result
Upper limit value test result
Gear L R
VAA’
VPP’
VBB’
nPP’
nBB’
3rd 1
82.7
81.9
65.9
71.8
77.9
9443
10246 2
66.4
71.9
9457 3
82.2
67.0
72.8
78.1
9575
10272
Average
82.4
82.3
72.2
78.0
9492
10254
ASEP試験の試験方法の説明となります。
Regulatory value （～2016）
Upper limit point
（2017～）
Reference point
Lower limit point
Lower limit value test result
Gear L R
VAA’
VPP’
VBB’
nPP’
nAA’
4th 1
70.7
71.1
26.3
34.0
39.9
3706
2867 2
70.8
26.2
33.8
39.7
3684
2856 3
25.9
34.2
40.1
3728
2823
Average
71.0
26.1
2848

9. Example of ASEP measurement - If exemption provisions apply.
ASEP exemption:
If the variation of the exit engine speed nBB’ relative to the reference point is below 0.05×（ｓ－nidle), then the ASEP does not apply.
Vehicle H: CVT model; Max. output = 37.7kW; Vehicle weight =250 kg; PMR＝116; ｓ＝7500rpm; nidle=1300 rpm
Reference point
Upper limit point
Lower limit point
Std.
nPP’　(rpm）
<Reference> Final test result
Lwot　(dB）
◆Reference point
　VPP’=50km/h
◆Upper limit point
　nBB’=3.4×PMR-0.33（ｓ-nidle）+nidle　=5691
　VBB’≦80km/h
◆Lower limit point
　nAA’=0.1×（ｓ-nidle）+nidle　=1920
　VAA’≧20km/h
Test result
Vehicle speed　（km/h）
Engine speed　（rpm）
Noise(dB)
Condition
VAA’
VPP’
VBB’
nAA’
nPP’
nBB’ L R
Upper limit
VBB’≦80
72.5
75.4
80.0
nBB’≦5691
3879
4585
4810
78.3
79.3
Reference point －
41.6
50.0
60.1
3112
4437
4804
77.5
80.2
Lower limit
VAA’≧20
20.0
40.6
56.2
nAA’≧1920
2379
5094
5112
80.6
82,3
Differences from the value at reference point nBB’ 4,804 rpm are below “0.05×（s-nidle）=310rpm” for both upper and lower limits, and therefore the exemption applies.
As it is unable to adjust the engine speed, measurements are made at VAA’=20km/h and VBB’=80km/h.

10. Questions or comments can be addressed to Daniela Leveratto,
IMMA Technical Director, at the following
Thank you!