Compression release engine brake with selectively reduced engine exhaust noise
First Claim
1. In a compression release engine brake for braking an associated internal combustion engine by using a first mechanical motion of the engine to cause an exhaust valve of the engine to open near the end of a compression stroke of an engine cylinder associated with said exhaust valve, said engine brake including an output member which acts on an exhaust valve mechanism in response to said first mechanical motion in order to open said exhaust valve, said output member being normally spaced from said exhaust valve mechanism during braking operation by a predetermined clearance, said clearance producing a delay between the commencement of said first mechanical motion and the opening of said exhaust valve, the improvement comprising:
- clearance selection means operable by a human operator of said engine during operation of said engine; and
means responsive to said clearance selection means for modifying said clearance to modify the delay between the commencement of said first mechanical motion and the opening of said exhaust valve, said clearance having a first predetermined dimension during normal engine braking operation of said engine brake, and wherein said means for modifying changes the dimension of said clearance from said first predetermined dimension to a second predetermined dimension which produces an amount of engine braking which is lower than the amount of engine braking produced during said normal engine braking operation.
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Accused Products
Abstract
In order to make the use of compression release engine brakes on the internal combustion engines of vehicles more acceptable in areas (e.g., urban areas) where high levels of engine exhaust noise are undesirable, the operator of the vehicle can adjust the "lash" of the engine brake to reduce engine exhaust noise whenever desired. The "lash" of the engine brake is the "at rest" clearance between engine brake slave piston and the engine exhaust valve mechanism operated on by the slave piston to produce engine braking. Engine exhaust noise associated with engine braking is reduced by reducing this lash or clearance so the engine brake opens exhaust valves in the engine at lower engine cylinder pressures, thereby reducing the associated exhaust noise. Despite the reduced exhaust noise, the engine brake still provides a substantial amount of engine braking horsepower.
39 Citations
13 Claims
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1. In a compression release engine brake for braking an associated internal combustion engine by using a first mechanical motion of the engine to cause an exhaust valve of the engine to open near the end of a compression stroke of an engine cylinder associated with said exhaust valve, said engine brake including an output member which acts on an exhaust valve mechanism in response to said first mechanical motion in order to open said exhaust valve, said output member being normally spaced from said exhaust valve mechanism during braking operation by a predetermined clearance, said clearance producing a delay between the commencement of said first mechanical motion and the opening of said exhaust valve, the improvement comprising:
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clearance selection means operable by a human operator of said engine during operation of said engine; and means responsive to said clearance selection means for modifying said clearance to modify the delay between the commencement of said first mechanical motion and the opening of said exhaust valve, said clearance having a first predetermined dimension during normal engine braking operation of said engine brake, and wherein said means for modifying changes the dimension of said clearance from said first predetermined dimension to a second predetermined dimension which produces an amount of engine braking which is lower than the amount of engine braking produced during said normal engine braking operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification