Effects of some functional parameters on noise pollution of John Deere ۳۳۵۰ and New Holland ۱۵۵ tractors

In this study, noise pollution from the John Deere ۳۳۵۰ and New Holland ۱۵۵ tractors was measured at three operator-related positions: ۱۰ cm from the driver’s ear and at distances of ۷.۵ and ۲۰ m from the tractor centerline, as they traveled over asphalt and soil surfaces. Measurements were conducted under three engine speeds (۱۰۰۰, ۱۵۰۰, and ۲۰۰۰ rpm) and three gear settings (gears ۱, ۲, and ۳), with three replications for each condition. Data were analyzed using a factorial test within a completely randomized design. Results indicated that noise levels increased with higher engine speeds and gear settings on both surfaces. The main factors had a statistically significant effect on noise emission levels in both tractors at the ۱% probability level. For the John Deere ۳۳۵۰, noise levels at the driver’s ear position exceeded the standard limit of ۸۵ dB (A) at all gear and speed combinations on asphalt, except for ۱st gear at ۱۰۰۰ rpm. The New Holland ۱۵۵ exhibited lower noise levels at the driver’s ear compared to the John Deere ۳۳۵۰, likely due to the presence of an enclosed cab.

کلیدواژه ها:

Engine speed ، Exposure time ، Gear ratio ، Noise pollution ، Tractor