US5372109A — Exhaust modulator

Claim 1

Independent Claim 61 words

An exhaust modulator for an exhaust system of an internal combustion engine, comprising a flow control means operable to control the flow of exhaust gases along at least one bleed flowpath so as to achieve different predetermined rates of increase of back pressure with increasing engine r.p.m., said flow control means being operable in response to at least one operating parameter.

Claim 2

Dependent Claim 61 words

An exhaust modulator for an exhaust system of an internal combustion engine, comprising a flow control means operable to control the flow of exhaust gases along at least one bleed flowpath so as to achieve different predetermined rates of increase of back pressure with increasing engine r.p.m., said flow control means being operable in response to at least one operating parameter.

Claim 3

Dependent Claim 20 words

An exhaust modulator according to claim 1 wherein the flow control means are operable in response to engine operating parameters.

Claim 4

Dependent Claim 47 words

An exhaust modulator according to claim 1 wherein the rate of flow of exhaust gas through said at least one bleed flowpath is varied to produce a relatively low back pressure to assist in engine warm up and a relatively high back pressure to facilitate engine braking.

Claim 5

Dependent Claim 24 words

An exhaust modulator according to claim 1 wherein operation of the flow control means is governed by the rate of flow of exhaust gas.

Claim 6

Dependent Claim 19 words

An exhaust modulator according to claim 1 wherein the flow control means further comprises at least one reed valve.

Claim 7

Dependent Claim 31 words

An exhaust modulator according to claim 5 further comprising a first reed valve having a certain stiffness and a second reed valve having a higher stiffness than the first reed valve.

Claim 8

Dependent Claim 22 words

An exhaust modulator according to claim 6 wherein the second reed valve is arranged to control movement of the first reed valve.

Claim 9

Dependent Claim 23 words

An exhaust modulator according to claim 6 wherein a stop is provided to limit movement of at least one of said reed valves.

Claim 10

Dependent Claim 25 words

An exhaust modulator according to claim 8 wherein the stop is in the form of a strap overlaying at least one of said reed valves.

Claim 11

Dependent Claim 31 words

An exhaust modulator according to claim 1 wherein the flow control means comprises an orifice defining a bleed flowpath and a disc biased toward said orifice to close the bleed flowpath.

Claim 12

Dependent Claim 27 words

An exhaust modulator according to claim 10 wherein more than one orifice and biased disc is provided, each disc being biased by resilient means of different stiffness.

Claim 13

Dependent Claim 19 words

An exhaust modulator according to claim 10 wherein each disc is biased by resilient means having a different preload.

Claim 14

Dependent Claim 116 words

An exhaust modulator for an exhaust system of an internal combustion engine, comprising a body defining a flowpath therethrough for engine exhaust gases, a gate in the exhaust flowpath movable between an open and a closed position and at least one bleed flowpath communicating between opposite sides of the gate, and a flow control means operable to control the flow of exhaust gases along said at least one bleed flowpath so as to limit the increase of back pressure applied to the engine to different predetermined increasing rates as engine r.p.m. increases, as required for operation of the modulator in selected modes, said flow control means being operable in response to at least one operating parameter.

Claim 15

Dependent Claim 116 words

An exhaust modulator for an exhaust system of an internal combustion engine, comprising a body defining a flowpath therethrough for engine exhaust gases, a gate in the exhaust flowpath movable between an open and a closed position and at least one bleed flowpath communicating between opposite sides of the gate, and a flow control means operable to control the flow of exhaust gases along said at least one bleed flowpath so as to limit the increase of back pressure applied to the engine to different predetermined increasing rates as engine r.p.m. increases, as required for operation of the modulator in selected modes, said flow control means being operable in response to at least one operating parameter.

Claim 16

Dependent Claim 25 words

An exhaust modulator according to claim 13 wherein said at least one bleed flowpath extends as a by-pass channel (96, 100, 97) through the body.

Claim 17

Dependent Claim 35 words

An exhaust modulator according to claim 14 wherein said at least one bleed flowpath is adapted to be closed by a valve including at least one flow port and piston movable to close the port.

Claim 18

Dependent Claim 16 words

An exhaust modulator according to claim 15 wherein bleed flowpaths having different cross-sectional areas are provided.

Claim 19

Dependent Claim 41 words

An exhaust modulator according to claim 13 including sensing means for producing signals representative of said at least one operating parameter, the flow control means being responsive to the signals to control the flow along said at least one bleed flowpath.

Claim 20

Dependent Claim 34 words

An exhaust modulator according to claim 17 wherein the sensed operating parameter is one of exhaust gas back pressure, engine temperature, vehicle cab temperature, engine speed, vehicle speed, exhaust emissions and engine oil pressure.

Claim 21

Independent Claim 106 words

A method of operating an exhaust modulator comprising a body defining a flowpath therethrough for engine exhaust gases, a gate in the exhaust flowpath which is movable between an open and a closed position; at least one bleed flowpath communicating between opposite sides of the gate, and flow control means operable to control the flow of exhaust gases along said at least one bleed flowpath the method comprising sensing at least one operating parameter and operating the flow control means in response to said at least one operating parameter to change the rate of increase of back pressure imposed on the engine with increasing engine r.p.m.

Claim 22

Independent Claim 106 words

A method of operating an exhaust modulator comprising a body defining a flowpath therethrough for engine exhaust gases, a gate in the exhaust flowpath which is movable between an open and a closed position; at least one bleed flowpath communicating between opposite sides of the gate, and flow control means operable to control the flow of exhaust gases along said at least one bleed flowpath the method comprising sensing at least one operating parameter and operating the flow control means in response to said at least one operating parameter to change the rate of increase of back pressure imposed on the engine with increasing engine r.p.m.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-12-12	1998-06-13	1998-12-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-12-12	2002-06-13	2002-12-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-12-12	2006-06-13	2006-12-13	$7700.00	Window Closed / Lapsed

Exhaust modulator

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