Detection and identification of illegal-modified private cars through frequency band analysis

Post-purchase-illegal-modification of road vehicles' exhaust systems by vehicle fanatics for loudness has caused an upsurge in nuisances to local residences when driven and rallied during late night and early mornings. Traditional enforcement measures rely on setting up roadblocks by the Police at rallying hotspots. These measures involve the judgement of individual police officer and can be subjective. With the aid of noise monitoring equipment, the accuracy and efficiency of on-site exhaust system-modified vehicle detection can be enhanced. Since the sound profile of a single-vehicle exhaust cannot be captured by simple roadside noise level measurements alone, segregation and analysis of the noise spectrum are employed to identify vehicles with modified exhaust systems. The paper presents the findings of investigating the feasibility and accuracy of off-the-shelf devices for detecting vehicles fitted with modified exhaust systems, with private cars being the primary target. A pilot test by roadside noise monitoring has been conducted with a sound level meter and an acoustic camera and revealed an on-site accuracy of up to 75%. Data collected during the tests were further used to explore the applicability of integrating artificial intelligence with traditional noise monitoring devices.

METHODS FOR EVALUATING THE EFFICIENCY OF TURBOCHARGING SYSTEM OF PISTON ENGINE WITH POWER TURBINE

The analysis of existing methods for assessing the loss of gases performance in the flow part of turbocharging system of piston engine is presented. It is shown that the exergy method provides a complete picture about of local energy transformations in the intake and exhaust systems of a piston engine, which makes it possible to use it to evaluate the efficiency of turbocharging system of piston engine with power turbine when forcing a piston engine by on the average effective pressure.

Design and evaluating efficiency of gas exhaust system silencer of outboard motor SEA PRO 2.5

The article presents the results of developing and evaluating the effectiveness of the silencer of outboard motor SEA PRO 2.5 made in China. The experiments were carried out in a large experimental pool of Astrakhan State Technical University, with the use of a noise meter-spectrum analyzer Ecophysics-110 of the first class, with the software Signal+3G Light. In the theoretical analysis of the development, it has been suggested that the efficiency of silencers of exhaust systems of outboard motors could have a smaller effect than with cars, since at underwater exhaust the noise reduction will occur from the water layer when the motor is submerged. It has been proved that using a silencer in underwater exhaust systems of outboard motors can increase the aerodynamic drag for gases and reduce power. To test the theoretical assumptions, there was made a silencer for the gas exhaust system of the outboard motor SEA PRO 2.5 from stainless steel perforated sponge. It was determined that the net effect of the silencer (excluding water silencing) could be heard at low frequencies (up to 125 Hz) and makes up to 12.7 dba at full speed of the motor. The average equivalent sound level is reduced up to 4.5 dba at low speed, and at full speed of the outboard motor is practically not evident. In addition, the outboard motor noise level was reduced by water and made at full speed up to 22 dba for frequencies over 2000 Hz; for average equivalent noise level it made 15 dba. The combination of noise reduction by water and by a silencer helps to reduce noise at low and high sound frequencies, which is a positive effect of the developed device.