Why does the BYD Qin keep making noise after turning off?

[MacMalachi]

The reason why the BYD Qin keeps making noise after turning off is due to the slight deformation caused by thermal expansion and contraction of the exhaust pipe. When the vehicle is in motion, the exhaust pipe is continuously heated by the engine's combustion exhaust, reaching temperatures of several hundred degrees Celsius. After stopping the vehicle, the temperature of the exhaust pipe drops rapidly due to the good thermal conductivity of the metal material and the thin walls of the exhaust pipe, resulting in thermal contraction. The BYD Qin is equipped with a plug-in hybrid system consisting of a 1.5T engine and an electric motor, with a combined maximum output power of 295 horsepower and a peak torque of 479 Nm. The vehicle dimensions are 4740mm in length, 1770mm in width, and 1480mm in height, with a wheelbase of 2670mm. In terms of exterior design, the BYD Qin continues the concept car's design, with chrome decorations added to both sides of the front bumper and LED daytime running lights integrated into the headlights. For the interior, the BYD Qin features a dark upper and light lower color scheme, equipped with a three-spoke multifunction steering wheel and a large-sized display screen on the center console.