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K. Kulkarni et al.
1 Introduction
Passenger cabin of vehicle which is running on the road is subjected to various
types of noise interventions, out of that prominent are road noise, wind noise and
engine noise. Though technology has taken a leap ahead and we have managed to
reduce engine and transmission noise to a great extent other parameters are majorly
influenced by environmental conditions and are uncontrolled [1].
Cabin acoustic is directly proportional to cabin air leakage. Higher the rate more
the noise inside the cabin. Uncontrolled and unintended cabin leakage happens
mainly because of gaps formed due to parts assembly interface, gaps between body
panels, misfit grommets used for electrical wiring harness and to cover PLP holes,
steering column cup assembly gap in floor or firewall, suspended pedal assembly
mountings, gaps between seals for doors and glasses. Even after pushing significant
efforts during the early stage of design to minimize the mentioned unintended gaps,
it may exist due to assembly failure, design failure, or manufacturing failure.
Considering all the above parameters it is important to identify the leakage sources,
review the design in the respective area and find appropriate solutions to stop or
minimize the air leakages.
2 Testing Methodology, Experimental Setup and Testing
Procedure
2.1 Air Leakage Testing Methodology
In the overall process of evaluation of air leakage below are the main stages:
1. Current vehicle air leakage evaluation: Baseline value
2. Identify the leakage areas
3. Close or minimizes the leakages
4. Regularize the solutions.
The process is elaborated in Fig. 1.
2.2 Experimental Setup
Cabin air leakage of the vehicles is tested using body (cabin) leak tester also known
as BLT machine. Figure 2 shows the block diagram of body leak test rig available
at test laboratory. The vehicle is tested with constant cabin pressure methodology
by maintaining 150 kPa in the cabin. Before connecting vehicle to the machine
its standard practice to ensure that vehicle is in ignition off condition, AC is in
recirculation mode, air extractors are closed (sealed with tape) and all window glasses
K. Kulkarni et al.
1 Introduction
Passenger cabin of vehicle which is running on the road is subjected to various
types of noise interventions, out of that prominent are road noise, wind noise and
engine noise. Though technology has taken a leap ahead and we have managed to
reduce engine and transmission noise to a great extent other parameters are majorly
influenced by environmental conditions and are uncontrolled [1].
Cabin acoustic is directly proportional to cabin air leakage. Higher the rate more
the noise inside the cabin. Uncontrolled and unintended cabin leakage happens
mainly because of gaps formed due to parts assembly interface, gaps between body
panels, misfit grommets used for electrical wiring harness and to cover PLP holes,
steering column cup assembly gap in floor or firewall, suspended pedal assembly
mountings, gaps between seals for doors and glasses. Even after pushing significant
efforts during the early stage of design to minimize the mentioned unintended gaps,
it may exist due to assembly failure, design failure, or manufacturing failure.
Considering all the above parameters it is important to identify the leakage sources,
review the design in the respective area and find appropriate solutions to stop or
minimize the air leakages.
2 Testing Methodology, Experimental Setup and Testing
Procedure
2.1 Air Leakage Testing Methodology
In the overall process of evaluation of air leakage below are the main stages:
1. Current vehicle air leakage evaluation: Baseline value
2. Identify the leakage areas
3. Close or minimizes the leakages
4. Regularize the solutions.
The process is elaborated in Fig. 1.
2.2 Experimental Setup
Cabin air leakage of the vehicles is tested using body (cabin) leak tester also known
as BLT machine. Figure 2 shows the block diagram of body leak test rig available
at test laboratory. The vehicle is tested with constant cabin pressure methodology
by maintaining 150 kPa in the cabin. Before connecting vehicle to the machine
its standard practice to ensure that vehicle is in ignition off condition, AC is in
recirculation mode, air extractors are closed (sealed with tape) and all window glasses