Danes berem, da Tenneco razvija izpušni sistem z dodanim zvočnikom, ki emitira prilagodljiv zvok. To si predtavljam nekako tako, kot da motor špila na playback. Ta sistem je bolj kompakten od navadnih dušilcev in očitno že poskušajo zanj navdušiti (tudi) proizvajalce elekričnih vozil.

As batteries, electric motors and power electronics take up more space beneath vehicles, engineers must find new ways to tune a vehicle's exhaust sound. Tenneco engineers are also working on exhaust sound systems for full-electric vehicles.
This year, the Department of Transportation passed a requirement that by 2020 electric vehicles will have to make noise to alert pedestrians when they are driven under 19 mph.
Today that's mostly done by varying the size of the muffler or with electronic valves that adjust back-pressure.
Tenneco engineers have created a prototype system that uses a smaller, standardized muffler that has a speaker enclosed in a sphere alongside the tailpipe.
www.autonews.com/art...ill-rumble

Očitno gre pri variacijah na temo zvočnika v izpušnem sistemu za precej kompleksne vaje, saj so podobno zadevo že leta 2013 pokazali v Frankfurtu. Morda tudi proizvajalci avtomobilov ne kažejo tako velikega navdušenja nad tovrstnimi sistemi, kot bi to radi v Tennecu.

Tenneco announced today a new dimension in delivering signature exhaust sounds for vehicles. The company unveiled its Tenneco Software Based Signature Sound System at the 2013 Frankfurt Motor Show. This innovative acoustic technology can provide custom designed exhaust tones – ranging from comfort to sporty – by enhancing the sound generated by the engine to better support the vehicle’s brand image.
"As vehicle manufacturers develop engine strategies to meet stringent fuel economy and CO2 emissions targets, the ability to differentiate that vehicle’s sound can be compromised," said Tim Jackson, executive vice president, technology, strategy and business development, Tenneco. "Our soundsystem demonstrates how we can provide our customers with enabling technologies that meet their regulatory targets, and at the same time, use our technology to help to enhance their vehicle’s image and brand with a signature sound."
The signature sound system features a combined audio controller and amplifier module and a specially designed plug-in loudspeaker. The loudspeaker produces sound near the vehicle tailpipe where it mixes with the sound created by the engine, resulting in the desired signature sound characteristic. The loudspeaker does not require a direct connection to the exhaust system, which helps to maximize vibration decoupling and thermal isolation.
www.autonews.com/art...ill-rumble

Igranje z izpušnim sistemom ima že brado, saj bo kmalu minilo 20 let od potrditve patenta za "aktiven sistem uravnavanja hrupa pri motorju z notranjim zgorevanjem", ki pa je bil očitno zamišljen za dušenje ropota. Nosilec je Tenneco Automotive.

An active noise conditioning system for use with a combustion engine exhaust system is provided. A controller receives an exhaust noise signal, along with various other feedback signals for producing an anti-noise signal in response to the input signals. An amplifier is provided for receiving and amplifying the anti-noise signal. A wave generator receives the amplified anti-noise signal and generates an audio anti-noise signal. The output of the wave generator is collocated with the exhaust pipe of the exhaust system, where the audio anti-noise signal and the exhaust noise are acoustically coupled, which effects cancelling of the exhaust noise.
www.freepatentsonlin...48168.html

Eno leto prej pa je bil Hondi odobren patent za sistem generiranja opozorilnega zvoka električnega vozila v odvisnosti od njegove vožnje in hrupa v okolici avta.

Based on detected information from a start sensor, a rotational speed sensor (or a vehicle speed sensor), and an accelerator opening sensor, a simulated sound selector device controls a simulated sound source device to generate a simulated sound signal corresponding to an operating condition of an electric vehicle when it starts, runs and is accelerated or decelerated, and also controls a sound level switcher device to adjust the level of the simulated sound signal. The simulated sound signal which is generated by the simulated sound source device and adjusted in level by the sound level switcher device is amplified by amplifiers, which drive respective loudspeakers to produce simulated sounds. The sound level switcher device is also controlled based on an ambient noise level detected by a noise sensor.
patents.google.com/p...635903A/en

Toliko hrupa okrog hrupa, čeprav je daleč najpomembnejša funkcija avtomobila, da nas vozi od A do B in nazaj - udobno, varno in tiho. :-)