Quieter Cabin Through Reduction in Uncontrolled …
307
Table 1 Air leakage test values and in cabin noise level for different segment vehicles without air
leakage improvement actions
Before implementation of improvement actions
Vehicle
Test cabin pressure
(kPa)
Leak rate
In cabin noise level
(db)
EBHS (cm 2 ) Flow rate (CFM)
Car (mid
segment)
150
70
254
71
SUV
(monocoque)
150
119
430
69
SUV (body on
chassis)
150
91
330
72
3 Results and Discussions
3.1 Cabin Air Leakage
Table 1 shows the BLT readings for different segments of the vehicles in India.
The tests were carried out with constant pressure method and following all standard
practices mentioned in the test methodology and experimental Setup paragraph.
Vehicle tested includes Car (mid-segment), SUV (monocoque), and SUV (Body on
Chassis).
3.2 Improvement Actions
After getting the leakage (airflow) rate from BLT machine next task is to detect the
leakages and take countermeasures. To know the exact root cause, during or after
BLT, leakages are identified with touch and feel, using smoke machine, stethoscope
and soap solutions wherever applicable. One, two or multiple methods from the
above list can be applied as per the requirement to detect the leakages. Once leakage
areas identified following solutions are to be considered which may prove as effective
solutions at different levels of manufacturing (shops) and according to nature of gap
or leakage.
Body shop actions: Application of expandable strips, butyl stickers, expansion
baffles, mastic or spot weldable sealers, etc. Figure 4 shows the snaps of some of the
solutions.
Paint shop actions: Application of paint sealers, paintable stickers, melt plugs,
paintable (tesa) tapes, etc. Figure 5 shows the snap of paintable sticker.
TCF (trim, chassis, and final)/Assembly shop actions: Rubber grommets, clips
with foams, closed-cell foams, acoustic plugs, stickers, gaskets, etc. Figure 6 shows
the snaps of application of closed-cell foam.
307
Table 1 Air leakage test values and in cabin noise level for different segment vehicles without air
leakage improvement actions
Before implementation of improvement actions
Vehicle
Test cabin pressure
(kPa)
Leak rate
In cabin noise level
(db)
EBHS (cm 2 ) Flow rate (CFM)
Car (mid
segment)
150
70
254
71
SUV
(monocoque)
150
119
430
69
SUV (body on
chassis)
150
91
330
72
3 Results and Discussions
3.1 Cabin Air Leakage
Table 1 shows the BLT readings for different segments of the vehicles in India.
The tests were carried out with constant pressure method and following all standard
practices mentioned in the test methodology and experimental Setup paragraph.
Vehicle tested includes Car (mid-segment), SUV (monocoque), and SUV (Body on
Chassis).
3.2 Improvement Actions
After getting the leakage (airflow) rate from BLT machine next task is to detect the
leakages and take countermeasures. To know the exact root cause, during or after
BLT, leakages are identified with touch and feel, using smoke machine, stethoscope
and soap solutions wherever applicable. One, two or multiple methods from the
above list can be applied as per the requirement to detect the leakages. Once leakage
areas identified following solutions are to be considered which may prove as effective
solutions at different levels of manufacturing (shops) and according to nature of gap
or leakage.
Body shop actions: Application of expandable strips, butyl stickers, expansion
baffles, mastic or spot weldable sealers, etc. Figure 4 shows the snaps of some of the
solutions.
Paint shop actions: Application of paint sealers, paintable stickers, melt plugs,
paintable (tesa) tapes, etc. Figure 5 shows the snap of paintable sticker.
TCF (trim, chassis, and final)/Assembly shop actions: Rubber grommets, clips
with foams, closed-cell foams, acoustic plugs, stickers, gaskets, etc. Figure 6 shows
the snaps of application of closed-cell foam.