Electrically controlled exhaust valve

Abstract

An exhaust system for a motor vehicle having a variable displacement engine includes an exhaust valve assembly that is moveable between an open position and a position blocking at least some of the exhaust gases. The blocking of some the exhaust gases increases backpressure that reflects sound waves. The reflection of sound waves provides for the conditioning of noises eminating from the exhaust system. The exhaust valve assembly utilizes an electric actuator. The exhaust valve assembly includes heat insulation features for isolating the electric actuator from heat radiating from the exhaust pipe.

Description

BACKGROUND OF THE INVENTION [0001] This invention generally relates to an exhaust system for a motor vehicle having a variable displacement engine, and specifically to an exhaust valve disposed within the exhaust system for controlling noise emissions from the exhaust system. [0002] A variable displacement engine controls actuation of specific cylinders within an engine. Typically, all cylinders of an multiple cylinder engine are providing power at all times during operation of the vehicle. Under some driving conditions, power produced from all cylinders is not required to propel the vehicle. The variable displacement engine shuts down some of the cylinders to conserve fuel and increase gas mileage. During periods of low engine demand only half of the cylinders operate to propel the vehicle. The selective actuation of engine cylinders provides the most noticeable improvements in fuel efficiencies for larger vehicles with larger engines. [0003] Selective actuation of specific cylinde...

AI Technical Summary

Benefits of technology

[0008] The housing for the actuator is supported a distance from the exhaust pipe by a valve neck. The valve neck is a tubular member having flanges at each end. The tubular configuration of the valve neck reduces the amount of thermal energy transmitted from the exhaust pipe to the housing. Electric actuators are dependable and relatively inexpensive, and are therefore more desirable than alternatively powered actuators. The reduction in thermal conduction between the valve body and the support housing prevents a substantial amount of heat from radiating to the electric actuator. The exhaust system of a vehicle produces high temperatures that present a challenge to the use of an electric actuator. It is for this reason that the exhaust valve of this invention includes features that isolate the electric actuator from thermal energy produced by the exhaust pipe.

[0009] Accordingly, the exhaust valve assembly of this invention utilizes an electric actuator to provide conditioning of noise emitted from the exhaust system to provide a consistent desired sound regardless of changes in engine displacement.

Problems solved by technology

The exhaust system of a vehicle produces high temperatures that present a challenge to the use of an electric actuator.

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