Truck and Bus Exhausts Systems

In many trucks all or most of the exhaust system is visible. Often in such trucks the silencer is surrounded by a perforated metal sheath to avoid people getting burnt by touching the hot silencer. This sheath is normally plated with chrome, for decorative purposes. Part of the pipe between the engine and the silencer is often flexible metal industrial ducting, as in the image in the section "Terminology". Sometimes a large diesel exhaust pipe is vertical, to blow the unhealthy, hot noxious gas  away from people. An exhaust pipe of this nature often has a hinged metal flap to stop road debris, insects, birds and rainwater from falling into it. Sometimes these exhaust pipes have some flex connector attached with it. This helps in minimising the effects of the vibration from the engine to the exhaust system.