Air control valve for exhaust gas purifying apparatus

• US 4,009,986 A
• Filed: 05/12/1975
• Issued: 03/01/1977
• Est. Priority Date: 01/14/1972
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Eckert, Konrad
• Primary Examiner(s): Favors, Edward G.
• Application Number:
  US05/576,265
• Time in Patent Office: 659 Days
• Field of Search: 431/90, 431/12, 251/335 A, 137/99, 137/100, 137/483, 137/500, 23/277 C
• US Class Current: 431/90
• CPC Class Codes: F01N 3/18 characterised by methods of operation; Control
• CPC Class Codes: F01N 3/22 Control of additional air supply only, e.g. using by-passes or variable air pump drives
• CPC Class Codes: F01N 3/222 using electric valves only
• CPC Class Codes: F01N 3/227 using pneumatically operated valves, e.g. membrane valves
• CPC Class Codes: Y10T 137/2521 Flow comparison or differential response

Abstract

In an exhaust gas purifying apparatus which includes a reactor in the exhaust line of an internal combustion engine there is provided a heater burner to which there is delivered an air-fuel mixture and which heats the reactor for rapidly bringing it to operating temperatures when the engine is started. In the air conduit through which combustion air for the air-fuel mixture is delivered to the burner there is provided a valve controlled in such a manner that the flow rate of combustion air remains constant and is thus independent of the said counterpressure at the heating burner and the output delivery of the air pump driving the combustion air.

Claims

1. In combination, a heating burner for heating a reactor of an exhaust gas purifying apparatus to operating temperatures, fuel supply means for delivering burner fuel to said heating burner, said fuel supply means including a fuel conduit, air supply means for delivering combustion air to said heating burner, said air supply means including a burner air conduit and an air pump disposed in the latter, and an air control valve, the air control valve including:

a. a movable valve member situated in said burner air conduit downstream of said air pump; and

b. regulating means coupling to said movable valve member for regulating the air quantities delivered to said heating burner to a constant value independently from the counterpressure at said heating burner and independently from the output delivery of said air pump, said regulating means including;

i. venturi nozzle disposed in said burner air conduit upstream of said movable valve member, said venturi nozzle having a narrowest flow passage section;

ii. a diaphragm having first and second sides;

iii. linkage means connecting said diaphragm with said movable valve member;

iv. means for communicating the pressure prevailing in said narrowest flow passage section with said first side of said diaphragm;

v. a spring means in engagement with said first side of said diaphragm; and

vi. means for communicating the pressure prevailing in said burner air conduit downstream of said venturi nozzle and upstream of said movable

3. The combination as defined in claim 1, wherein said movable valve member

4. The combination as defined in claim 1, including:

a. a solenoid valve in said fuel conduit;

b. an electric energizing circuit connected to said solenoid valve;

c. an on-off switch in said electric energizing circuit to close and open the latter; and

d. means for connecting said diaphragm with said on-off switch, whereby said fuel conduit is shut off by means of said solenoid valve when the air quantities flowing through said burner air conduit fall below a predetermined value.

2. In combination, a heating burner for heating a reactor of an exhaust gas purifying apparatus to operating temperatures, fuel supply means for delivering burner fuel to said heating burner, said fuel supply means including a fuel conduit, a fuel regulating valve having means for setting the throughgoing fuel quantities to a constant value, air supply means for delivering combustion air to said heating burner, said air supply means including a burner air conduit and an air pump disposed in the latter, and an air control valve, with the air control valve including:

a. a movable valve member situated in said burner air conduit downstream of said air pump; and

b. regulating means coupled to said movable valve member for regulating the air quantities delivered to said heating burner to a constant value independently from the counterpressure at said heating burner and independently from the output delivery of said air pump, and with the fuel regulating valve being formed as a diaphragm-type pressure differential valve having;

a. first and second chambers;

b. a diaphragm constituting a movable valve member of said pressure differential valve and separating said first and second chambers from one another;

c. channel means maintaining communication between said first and second chambers; and

d. adjustable throttle means in said channel means for varying the flow