U.S. patent application number 14/359350 was filed with the patent office on 2015-05-14 for cooling system for actively cooling an exhaust gas system.
The applicant listed for this patent is Bernd Helferich. Invention is credited to Bernd Helferich.
Application Number | 20150128578 14/359350 |
Document ID | / |
Family ID | 47297206 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150128578 |
Kind Code |
A1 |
Helferich; Bernd |
May 14, 2015 |
Cooling System for Actively Cooling an Exhaust Gas System
Abstract
A cooling system for actively cooling an exhaust gas system,
comprises an exhaust pipe which conducts an exhaust gas flow of an
internal combustion engine and an air-conducting element. The
air-conducting element surrounds the exhaust pipe and forms an
air-conducting channel. The exhaust pipe is cooled by an air flow
which flows through the air-conducting channel.
Inventors: |
Helferich; Bernd; (Mannheim,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Helferich; Bernd |
Mannheim |
|
DE |
|
|
Family ID: |
47297206 |
Appl. No.: |
14/359350 |
Filed: |
November 28, 2012 |
PCT Filed: |
November 28, 2012 |
PCT NO: |
PCT/EP2012/073824 |
371 Date: |
May 20, 2014 |
Current U.S.
Class: |
60/320 |
Current CPC
Class: |
F01N 2590/08 20130101;
F01N 13/082 20130101; F01N 13/143 20130101; F01N 2270/02 20130101;
F01N 2470/24 20130101; F01N 2260/022 20130101 |
Class at
Publication: |
60/320 |
International
Class: |
F01N 13/08 20060101
F01N013/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 2, 2011 |
DE |
10 2011 087 675.8 |
Claims
1-9. (canceled)
10. A cooling system for actively cooling an exhaust gas system,
having an exhaust pipe for discharging an exhaust gas flow from an
internal combustion engine, and an air-conducting element which
forms an air-conducting channel which cools the exhaust,
characterized by: a fan which moves a flow of air into the
air-conducting channel.
11. The cooling system according of claim 10, wherein: the fan
compresses the air flow to an elevated pressure level relative to
an ambient pressure.
12. The cooling system of claim 10, wherein: the fan supplies a
cooling air flow for the internal combustion engine as the air flow
to the air conducting channel.
13. The cooling system of claim 12, wherein: the air-conducting
element forms an air inlet opening which communicates with the
air-conducting channel, wherein the air-conducting channel is
connected via the air inlet opening to an engine compartment for
the internal combustion engine in order to supply the cooling air
flow.
14. The cooling system of claim 10, wherein: the air-conducting
element has at least two openings for the air-conducting channel,
both of the openings being arranged upstream of a discharge end of
the exhaust pipe.
15. The cooling system of claim 10, wherein: the exhaust pipe has a
Venturi nozzle arrangement, and the air-conducting element forms an
annular gap downstream of the Venturi nozzle arrangement.
16. The cooling system of claim 15, wherein: the air-conducting
element has at least two outlet openings for the air-conducting
channel, and the annular gap is arranged between the two outlet
openings.
17. The cooling system of claim 16, wherein: the annular gap
comprises a Venturi nozzle which draws ambient air into the
air-conducting channel.
Description
FIELD
[0001] The present disclosure relates to a cooling system for
actively cooling an exhaust gas system.
BACKGROUND
[0002] Due to current exhaust emission legislation, exhaust gas
post-treatment systems for reducing pollutant emissions are being
used in internal combustion systems, including Diesel engine
systems. In certain operating situations, the exhaust gases of such
engines can reach high temperatures. The exhaust gas post-treatment
systems may contain a diesel particulate filter (DPF) for filtering
out soot particles. The soot particles are deposited in the porous
filter wall of the DPF, so that the exhaust gas backpressure
increases with increasing clogging level of the DPF. In order to
regenerate the DPF and reduce clogging levels, the deposited soot
particles are burned off at regular intervals. For this purpose,
the temperature of the exhaust gas stream is temporarily increased
by appropriate measures to temperatures ordinarily above
600.degree. C. This may cause correspondingly high surface
temperatures of the exhaust pipe. If the exhaust pipe is a part of
an exhaust system for an agricultural machine for example, the hot
exhaust pipe may cause a burn injury to an operator of the machine.
Such a hot exhaust pipe may also cause a fire in the immediate
surroundings, for example when the machine is parked in a barn.
Finally, material deposited on the hot exhaust pipe can
self-ignite.
[0003] A jacketed exhaust pipe is known from DE 1 027 084. While
driving and depending on the speed, air led past the exhaust pipe
removes heat by convection between the exhaust pipe and the jacket
and dissipates it into the open air. Such a passive cooling system
may not function properly for agricultural vehicles such as
tractors, which generally travel at a slow speed or operate in
stationary mode when providing power via the power takeoff shaft
(PTO), because of insufficient air flow. It is desired to have a
cooling system for an exhaust gas system that is largely
independent of the travel speed.
SUMMARY
[0004] According to an aspect of the present disclosure, a cooling
system for actively cooling an exhaust gas system includes an
exhaust pipe for conducting a flow of exhaust gas from an internal
combustion engine and an air-conducting element, which is arranged
relative to the exhaust pipe such as to form an air-conducting
channel which cools the exhaust pipe by introducing an air flow
into the air-conducting channel. The cooling system also includes a
fan which pushes an air flow into the air-conducting channel.
[0005] This system ensures that the cooling power of the active
cooling system for the exhaust gas pipe is at least largely
independent of a vehicle speed and is dependent only on the cooling
power of the fan. In this way an active cooling is assured by an
air flow that is produced by the fan into the air-conducting
channel even during field work under load with an agricultural
machine having typical speeds of less than 10 km/h or in stationary
operation for outputting power via the power takeoff.
[0006] The fan preferably compresses the air flow to an elevated
pressure level relative to an ambient pressure. This guarantees,
even at low travel speed, a pressure gradient which creates an air
flow into the air-conducting channel. The ambient pressure is the
atmospheric air pressure.
[0007] In a preferred embodiment, the fan supplies cooling air flow
for the internal combustion engine and to the air-conducting
channel. Preferably, the air flow entering the air-conducting
channel is previously filtered by a filtering system of the cooling
system.
[0008] In a further preferred embodiment, the air-conducting
element has an air inlet opening into the air-conducting channel,
and the air-conducting channel is connected via the air inlet
opening to an engine compartment for the internal combustion engine
in order to supply the cooling air flow. The engine compartment
guarantees that an elevated pressure level can be adjusted, which
then causes the cooling exhaust stream to pass through the air
inlet opening into the air-conducting channel. The engine
compartment encloses the internal combustion engine, and includes a
hood, one or more panel parts, and also the bulkhead of a driver's
cab. Apart from an air supply opening to the fan unit and an air
outlet opening corresponding to the air inlet opening of the
air-conducting channel, the engine compartment is largely an
air-tight enclosure.
[0009] The fan is preferably a fan unit of a coolant system for the
internal combustion engine. Because such a cooling system
ordinarily has a fan unit, the increased pressure level towards the
exhaust gas system can be advantageously generated by the existing
engine cooling fan.
[0010] In a further preferred embodiment, the air-conducting
element has at least two outlet openings for the air conducting
channel, the first outlet opening being arranged in the vicinity of
a discharge opening of the exhaust pipe and the second outlet
opening being arranged upstream of the discharge opening. An
excessively high backpressure in the air-conducting channel is
advantageously avoided by the second outlet opening.
[0011] The exhaust pipe preferably has a Venturi nozzle arrangement
surrounding the exhaust pipe in order to draw in air, and the
air-conducting element forms an annular gap downstream of the
Venturi nozzle arrangement. This ensures in an advantageous manner
that cooling air is supplied to the exhaust gas via the Venturi
nozzles, whereby the high exhaust temperatures during regeneration
of the DPF are lowered in order to counteract the creation of
undesired nitrogen oxides in the exhaust pipe due to the high
temperatures.
[0012] The annular gap is preferably arranged between two outlet
openings of the air-conducting element. This guarantees that any
existing overpressure is dissipated to a certain extent via the
second outlet opening, so that no cooling air is blown off by the
annular gap, but instead additional cooling air is drawn in from
the exterior via the chimney effect that results downstream of the
annular gap.
[0013] The annular gap is preferably constructed as a Venturi
nozzle arrangement, for drawing ambient air into the air-conducting
channel. Thereby the Venturi nozzle arrangement in combination with
the chimney effect that results downstream in the exhaust pipe can
be used to draw in ambient air for supporting the cooling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective overall view of a cooling system
according to the invention for active cooling of an exhaust gas
system; and
[0015] FIG. 2 is a cross section through the cooling system of FIG.
1.
DETAILED DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows an agricultural vehicle 48 or tractor with a
cab 50, a frame 52. A hood or engine cover 70 covers an internal
combustion engine (not shown). An exhaust gas system 12 discharges
an exhaust gas flow 22. The internal combustion engine is arranged
inside an engine compartment 34 in a conventional manner. The
exhaust gas system 12 includes a soot particulate filter (not
shown), an exhaust pipe 14 and an air-conducting element 18 that
surrounds the exhaust pipe 14, forming an air-conducting channel
20. The exhaust gas system 12 can comprise additional components
(not shown), such as one or more catalytic converters.
[0017] The internal combustion engine has a conventional liquid
cooling circuit (not shown), with a high temperature heat exchanger
(not shown) to which cooling air drawn in from the surroundings via
a radiator grille, downstream filter inserts and a fan unit 28. The
cooling air directed into the engine compartment 34 is largely free
of contaminants due to the filter inserts. The compression of the
cooling air produced by the fan unit 28 leads to an elevated
pressure level of the cooling air in the engine compartment 34
relative to the ambient atmospheric pressure. The cooling air
directed through the high temperature heat exchanger and the engine
compartment 34 is introduced as a cooling air flow 26 for actively
cooling the exhaust gas system 12 in the air-conducting channel 20,
which is formed by the air-conducting element 18 which surrounds
the exhaust pipe 14.
[0018] In order to cool the exhaust gas flow 22 downstream of the
soot particulate filter 52, the exhaust pipe 14 has a Venturi
nozzle arrangement 42, as best seen in FIG. 2. The Venturi nozzle
arrangement 42 is formed by constructing the exhaust pipe 14 in two
parts, and constructing the upstream exhaust pipe element 54 so as
to form a discharge area 56, which extends in a nozzle shape into
the open end 58 of the downstream exhaust pipe element 60 of the
exhaust pipe 14. The Venturi nozzle arrangement 42 has a
substantially circular cross-section. The Venturi produces a
negative pressure which draws air out of the air-conducting channel
20 into the exhaust pipe 14 in order to cool the exhaust gas flow
22.
[0019] The air-conducting element 18 is formed in two parts in the
illustrated embodiment, consisting of an engine-side protective
cover 62, a horizontal protective cover 66 comprising two cover
shells 64, 64', and a vertical protective cover 68. The number of
parts from which the air-conducting element is formed can vary in
other embodiments of the invention.
[0020] The air-conducting element 18 surrounds the exhaust pipe 14
and thus forms an air-conducting channel 20 together with the
exhaust pipe 14. The air-conducting channel 20 is connected to the
engine compartment 34 via an air inlet opening 32. The air inlet
opening 32 is formed by constructing an air gap 72 between the
exhaust pipe 14 and the lateral engine cover 70. The air gap 72 is
covered with respect to the surroundings by the vertical protective
cover 66, which is formed in a half shell shape. In the assembled
state, the two cover shells 64, 64' of the horizontal protective
cover 66 form the second outlet opening 38, which is directed
downwards towards the ground and is arranged on the downstream end
of the protective cover 66. Due to the fact that the second outlet
opening 38 is directed downwards, both the sound and the hot
cooling air is discharged downwards in the direction of the
ground.
[0021] The transitional area from the horizontal protective cover
66 to the vertical protective cover 68 forms an annular gap 44. In
the present embodiment, the annular gap 44 is constructed as a
Venturi nozzle arrangement 46. The horizontal protective cover 66
has a discharge area 74 tapering down in the downstream direction,
which protrudes in a nozzle shape into the open end 76 of the
vertical protective cover 68. In this way, an intake region is
formed between the discharge region 74 and the open end 76, in
which intake region a negative pressure relative to the
surroundings is produced according to the Venturi principle upon
passage of a cooling airflow through the air-conducting channel 20,
so that ambient air is drawn into the air-conducting channel 20.
The cooling air flow enters the surroundings via the outlet opening
36 in the area of the discharge opening 40 for the exhaust pipe
14.
[0022] In addition, a filter element or perforated grid (not
shown), can be provided in the region of the annular gap 44 or in
the intake region of the Venturi nozzle arrangement 46, to prevent
coarse contaminants from clogging the air-conducting channel
20.
[0023] The air-conducting element 18 is thus a shield which
prevents contact with the hot exhaust pipe 14 by completely
surrounding the latter, and also an air-conducting channel 20
around the exhaust pipe 14, via which an actively introduced
airflow guarantees cooling.
LIST OF REFERENCE NUMBERS
[0024] 10 Cooling system 12 Exhaust gas system 14 Exhaust pipe 16
Internal combustion engine 18 Air-conducting element 20
Air-conducting channel 22 Exhaust gas flow 24 Air flow 26 Cooling
air flow 28 Fan unit 30 Cooling circuit 32 Air inlet opening 34
Engine compartment 36 Outlet opening 38 Outlet opening 40 Discharge
opening 42 Venturi nozzle arrangement
44 Annular gap
[0025] 46 Venturi nozzle arrangement 48 Agricultural vehicle
50 Cab
[0026] 52 Soot particulate filter 54 Exhaust pipe element 56
Discharge region
58 Open end
[0027] 60 Exhaust pipe element 62 Protective cover 64, 64' Cover
shell 66 Protective cover 68 Protective cover 70 Engine cover
72 Air gap
[0028] 74 Discharge region
76 Open end
[0029] While the disclosure has been illustrated and described in
detail in the drawings and foregoing description, such illustration
and description is to be considered as exemplary and not
restrictive in character, it being understood that illustrative
embodiments have been shown and described and that all changes and
modifications that come within the spirit of the disclosure are
desired to be protected. It will be noted that alternative
embodiments of the present disclosure may not include all of the
features described yet still benefit from at least some of the
advantages of such features. Those of ordinary skill in the art may
readily devise their own implementations that incorporate one or
more of the features of the present disclosure and fall within the
spirit and scope of the present invention as defined by the
appended claims.
* * * * *