High pressure turbine inlet duct and engine

A diesel engine comprising:

• an exhaust manifold;
• an intake manifold;
• one or more cylinders arranged to receive intake air from the intake manifold and to discharge exhaust gas to the exhaust manifold;
• a turbocharger including a turbine coupled to receive exhaust gas from the exhaust manifold and including a compressor coupled to supply intake air to the intake manifold;
• and
• a turbine inlet duct coupled to conduct exhaust gas from the exhaust manifold to the turbine of the turbocharger, said turbine inlet duct including:
• a cylindrical duct body defining a longitudinal axis;
• a frustoconical outlet nozzle connected at one end of the duct body and extending at from eighty to ninety degrees from the longitudinal axis, wherein the frustoconical outlet nozzle is connected to the turbine;
• and
• an inlet bell connected at the other end of the duct body and extending at from forty-five to fifty-five degrees from the longitudinal axis, wherein the inlet bell is connected to the exhaust manifold.