US 6,742,335 B2Granted

EGR control system and method for an internal combustion engine

AssigneeClean Air Power, Inc.

InventorsN. John Beck, Hoi Ching Wong, Kresimir Gebert

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Abstract

EGR mass fraction or a value indicative thereof can be calculated based on temperature measurements rather than mass flow and/or pressure measurements, hence negating the need for expensive and relatively unreliable measurement devices in an active EGR system for an internal combustion engine. The EGR system may be a low pressure EGR system configured to direct cooled, filtered EGR to the engine's air intake system using an effective, simple venturi and/or a continuously regenerated catalytic particulate trap. The resultant system can reduce NOx emissions in a diesel engine on the order of 50% and approximately 90% for CO, HC, and PM. NOx and other emissions can be reduced still further when the EGR system is combined with other pretreatment and/or after treatment devices. Many components of the low pressure EGR system are also usable in a passive EGR system.

Claims2

Dependent claims

A method comprising:

(A) exhausting gases from an exhaust manifold of a compression ignition engine;
(B) separating a portion of said exhaust gases from the remainder of said exhaust gases under the control of an EGR valve;
(C) removing particulates from at least said portion of said exhaust gases using an actively regenerated catalytic particulate trap;
(D) cooling said portion of said exhaust gases;
then
(E) filtering said portion of said exhaust gases;
then
(F) mixing said portion of said exhaust gases with air in a venturi of an air induction system to form a mixture, said venturi generating a suction pressure of about 0.06 atmospheres and having a throat Mach Number of about 0.3 at an airflow rate through the venturi of about 60 lb/min.;
and
(G) directing said mixture into an intake manifold of said engine;
(H) measuring
(1) a temperature of said portion of said exhaust gases after said portion is cooled,
(2) a temperature of said air, and
(3) a temperature of said mixture;
(I) calculating, based solely on the measuring step, a parameter indicative of a mass fraction of exhaust gases (mfegr) in said mixture;
and
(J) based on the calculating step, adjusting an EGR valve setting so as to adjust mfegr to at least approach a desired mfegr.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/193,257Filed 11 Jul 2002
Published: US 2004/0006978 A115 Jan 2004
Granted: 1 Jun 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

F02B 37/16
Control of the pumps: by bypassing charging air
F01N 3/021
For cooling, or for removing solid constituents of, exhaust: by means of filters
F01N 3/043
Using liquids: without contact between liquid and exhaust gases
F02M 26/06
With a single turbocharger: low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger…