Example 3 idle noises of diesel engines

Usually, the studies of noises in the car are reserved for the expertise of acousticians. This exclusivity can raise some issues concerning the development of the vehicle. Among these issues, the very specific vocabulary of these experts can comphcate the exchange of information between the different R D departments involved. 

Of course, we do not question the expertise of the acousticians, but we think it would be of great value to verify that their description of idle sounds is close to what consumers perceive and to share a more common lexicon within the company. In order to address this question, we conducted a smdy that had three underlying objectives  

Eleven idle noises of diesel engines were evaluated anonymously. They are coded in this paper by their short names (Table 20.3). These cars were chosen to represent different types of engine (3-, 4-, 6- and 8-cyIinder). 

The sounds were evaluated in a listening room and played at 104 dB (A) with two speakers and a subwoofer (2.1 Trans aural systan). Eor this study, we wanted to facilitate the description of the noises rather than to be representative of actual driving conditions. Therefore, the chosen level of listening is higher than the actual level in a car cockpit. 

Focus Ford Focus 2.0 TCDI 4-cylinder engine 

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