U.S. patent application number 13/394779 was filed with the patent office on 2012-07-12 for device and method for regulating the injection of a quantity of reducer in the gaseous phase.
This patent application is currently assigned to Peugeot Citroen Automobiles SA. Invention is credited to Christophe Charial.
Application Number | 20120174563 13/394779 |
Document ID | / |
Family ID | 42041512 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120174563 |
Kind Code |
A1 |
Charial; Christophe |
July 12, 2012 |
Device and Method for Regulating the Injection of a Quantity of
Reducer in the Gaseous Phase
Abstract
The invention relates to a device (16) for regulating the
injection of a quantity of reducer in the gaseous phase,
comprising: a reducer supply channel (18), a pressure regulator
(20) for regulating the pressure in the channel, members (24) for
detecting the pressure downstream of the regulator (20), a reducer
injector (22), and a computer controlling the injector according to
the measured pressure.
Inventors: |
Charial; Christophe;
(Pontchartrain, FR) |
Assignee: |
Peugeot Citroen Automobiles
SA
Velizy Villacoublay
FR
|
Family ID: |
42041512 |
Appl. No.: |
13/394779 |
Filed: |
July 26, 2010 |
PCT Filed: |
July 26, 2010 |
PCT NO: |
PCT/FR2010/051581 |
371 Date: |
March 7, 2012 |
Current U.S.
Class: |
60/274 ;
60/287 |
Current CPC
Class: |
F01N 2610/11 20130101;
Y02T 10/12 20130101; F01N 3/2066 20130101; F01N 2610/04 20130101;
F01N 2610/02 20130101; F01N 2610/1453 20130101; Y02T 10/24
20130101 |
Class at
Publication: |
60/274 ;
60/287 |
International
Class: |
F01N 3/08 20060101
F01N003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2009 |
FR |
0956182 |
Claims
1. A device for regulating the injection of a quantity of reducer
in gaseous phase comprising a line supplying the reducer, a
pressure regulator in the line, pressure detection instruments
downstream of regulator, a reducer injector, and a processor
controlling the injector as a function of the measured
pressure.
2. The device according to claim 1, further comprising pressure
detection instruments upstream of regulator.
3. The device according to claim 1, further comprising a
temperature sensor downstream and/or upstream of the pressure
regulator.
4. The device according to claim 1, the regulator further
comprising a first reducer entry chamber, a second chamber routing
the reducer towards the injector, a reducer passage between the
first chamber and the second chamber, whereby the reducer passage
is blocked above a certain pressure threshold in the second chamber
and the reducer passage is open below this pressure threshold.
5. The device according to claim 4, wherein the reducer passage is
in a piston rod that extends between the first and second chambers,
the rod supporting a piston head which is movable axially in the
second chamber, and a spring that pushes against the piston head
and is suitable for opening the reducer passage when the pressure
in the second chamber is lower than the threshold pressure and
suitable for closing the reducer passage when the pressure in the
second chamber is higher than the pressure threshold.
6. The device according to claim 1, further comprising a post
treatment line for exhaust gas, having one or more reservoirs for
storing reducer in gaseous phase.
7. A method for regulating the injection of a quantity of reducer
in gaseous phase in a line comprising the steps of supplying
reducer to an injector, regulating the pressure downstream of a
regulator, detecting the pressure downstream of the regulator, and,
controlling the opening time of the injector by a processor as a
function of the measured pressure.
8. The method according to claim 7, of further comprising detecting
the pressure upstream of the regulator, and emitting an anomaly
signal when the pressure upstream and/or downstream of the
regulator is above or below a threshold.
9. The method according to claim 7, whereby a post treatment line
comprises a plurality of reservoirs, the method further comprising
the step of detecting the pressure upstream of the regulator, and
switching the reducer supply to the line from one reservoir to
another when the detected pressure upstream of the regulator is
beyond a threshold.
10. The method according to claim 7, further comprising a step of
measuring the temperature upstream and/or downstream of the
regulator, through measurement of the temperature or through the
use of a model, whereby the opening time of an injector is also
controlled by a processor as a function of temperature.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National stage, under 35 U.S.C.
.sctn.371, of International App. No. PCT/FR2010/051581 which was
filed on Jul. 26, 2010 and claims priority to French Application
No. 0956182 which was filed on Sep. 10, 2009, and which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present disclosure relates to a device for regulating
the injection of a quantity of reducer in gaseous phase. A method
is also proposed for implementing this device.
[0003] Nitrogen oxides (NOx) originating from the exhaust gas of
internal combustion engines are linked to human health problems and
are a key element in the formation of "smog" (pollution clouds) in
cities. The legislature is imposing increasingly strict levels for
their reduction and/or their elimination from mobile or fixed
sources. To this end, a proven effective solution consists of
chemical reduction of NOx by addition of a reducing agent such as
NH.sub.3 (ammonia) upstream of a catalyst employing a specific
selective catalytic reduction (or SCR). This solution enables a
diesel engine to comply with increasingly strict emission
levels.
[0004] The problem faced by SCR is to bring the ammonia necessary
for the NOx reduction in the exhaust. The reducer must be stored on
the vehicle. Several concepts were developed to store the ammonia
on board: in the form of solid urea, in the form of liquid urea, in
aqueous solution, in the form of ammonium carbamate, etc.
[0005] Document FR-A-2 725 245 discloses a device for supplying an
internal combustion engine with fuel. The device comprises a pump
designed to draw fuel from a reservoir and an element sensitive to
the pressure existing in the supply line without bypass, connected
to the outlet of the pump and adapted to pilot the start up of the
pump. The device comprises furthermore an expansion regulator
placed in series in the supply line without bypass, connected to
the outlet of the pump, upstream of the location where the fuel is
used.
[0006] Document EP-A-1 198 740 describes a device for measuring the
flow of a fluid through a pressure regulator, whereby the device
comprises pressure sensors upstream and downstream of the
regulator.
[0007] Document US-A-2008 022670 discloses a device for injecting
liquid urea in an exhaust line. It uses a pressure regulator for
the liquid urea and a pressure sensor for the urea. The pressure
sensor measures the pressure of the urea supplied to the injector
and the regulator regulates the incoming pressure. When said
incoming pressure becomes too high, the urea returns to the urea
reservoir.
[0008] The disadvantage of storing and using liquid urea or urea in
aqueous solution is the requirement for large reservoirs, which
creates additional weight for the vehicle. For this reason, the use
of a reducing gas is preferred, but here the problem is in
developing an architecture for controlling the quantity of injected
reducing gas.
BRIEF SUMMARY
[0009] To this end, a device for regulating the injection of a
quantity of reducer in gaseous phase comprising a reducer supply
line, a pressure regulator in the line, instruments for detecting
the pressure downstream of the regulator, a reducer injector, and a
processor controlling the injection in function of the measured
pressure are provided.
[0010] In a variant, the device further comprises instruments for
detecting the pressure upstream of the regulator, whereby the
downstream pressure detection instrument, and if necessary the
upstream instrument, are for example a pressure sensor or a
pressure switch.
[0011] In a variant, the device further comprises a temperature
sensor downstream and/or upstream of the pressure regulator.
[0012] In a variant, the regulator comprises a first reducer entry
chamber, a second chamber that routes the reducer towards the
injector, a passage for the reducer between the first chamber and
the second chamber, whereby the passage is obturated above a
pressure threshold in the second chamber and the passage is open
below this pressure threshold, so that the pressure downstream of
the regulator can be increased.
[0013] In a variant, the passage extends through a piston rod that
connects the first and second chambers. The rod supports a piston
head movable in translation in the second chamber. A spring pushes
against the head of the piston and is suitable for opening the
passage when the pressure in the second chamber is lower than the
threshold and suitable for closing the passage when the pressure in
the second chamber is higher than the threshold.
[0014] In a variant, the reducer in gaseous phase comprises ammonia
(NH.sub.3), hydrogen (H.sub.2), or hydrocarbons (HC).
[0015] The device also includes a post treatment line for exhaust
gas, which comprises one or more storage reservoirs for a reducer
in gaseous phase, and wherein the device is connected to the
reservoir(s).
[0016] Also disclosed is a method for regulating the injection of a
quantity of reducer in gaseous phase in this type of post treatment
line for exhaust gas. The method comprises supplying a reducer to
the injector, regulating the pressure downstream of the regulator,
detecting the pressure downstream of the regulator, and,
controlling the opening time of the injector through the processor
in function of the measured pressure.
[0017] In a variant, the method further comprises the detection of
the pressure upstream of the regulator, and emission of a fault
signal when the pressure upstream and/or downstream of the
regulator is above or below a threshold.
[0018] In a variant, adapted to controlling a line comprising a
plurality of reservoirs, the method further comprises the detection
of the pressure upstream of the regulator, and switching the supply
of reducer to the line from one reservoir to another when the
detected pressure upstream of the regulator is below the
threshold.
[0019] In a variant, the method further comprises a step of
measuring the temperature downstream and/or upstream of the
regulator, by measuring the temperature or by using a model, while
the opening time of the injector is also controlled by the
processor as a function of the temperature.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0020] Other characteristics and advantages of the invention will
become clear by reading the following detailed description of the
implementation modes of the invention, provided only as an example
and with reference to the drawings which show:
[0021] FIG. 1, a vehicle equipped with a post treatment line for
exhaust gas;
[0022] FIG. 2, a regulating device for the reducer injection;
and
[0023] FIG. 3, a pressure regulator.
DETAILED DESCRIPTION
[0024] A device and a method for regulating the injection of a
quantity of reducer in gaseous phase are disclosed. The device
comprises a reducer supply line and a pressure regulator in the
line. The device also comprises detection instruments for the
pressure downstream of the regulator and a pressure controlled
reducer injector. The device also comprises a processor controlling
the injector as a function of the measured pressure. The processor
allows for precise control of the reducer gas flow. Furthermore,
this architecture controls the flow with a reduced number of
components, which reduces the cost of the assembly.
[0025] FIG. 1 shows a vehicle 10 comprising a line 12 for post
treatment of exhaust gas. Vehicle 10 comprises an engine 14, for
instance a diesel engine, to which line 12 is connected. Line 12
can comprise different exhaust gas treatment sites. For instance,
line 12 can comprise a denitrification site 15. The DeNOx
denitrification site 15 comprises a catalyst causing the reduction
of NOx by reaction with ammonia injected in line 12. Other sites
can be present in the line but are not shown.
[0026] FIG. 1 also shows a device 16 for regulating the injection
of a quantity of reducer in gaseous phase. Device 16 allows for the
injection of a reducer in gaseous phase. The reducer is, for
instance, hydrogen (H.sub.2) or hydrocarbons (HC). The reducer can
also be ammonia (NH.sub.3) used in site 15. The advantage of
injecting a reducer in gaseous phase is that it does not require
preliminary transformation of a liquid reducer into a gaseous
reducer, since this transformation must take place in very special
conditions which can be difficult to create. Furthermore, larger
quantities of reducer in gaseous phase can be available on board of
the vehicle for a much smaller storage weight. Device 16 is
connected to one or more reservoirs 17 which store the reducer. For
instance, reservoir 17 can be comprised of storage by absorption of
NH.sub.3 in a XCl.sub.2 type salt. The gas is released by adding
heat or by lowering the pressure.
[0027] FIG. 2 shows device 16 in more detail. Device 16 comprises a
reducer supply line 18. Line 18 is connected to reservoir 17. The
reducer is routed towards line 12 through line 18 starting from
reservoir 17. Device 16 further comprises a regulator 20 for the
pressure inside the line. Regulator 20 controls the pressure of the
reducer. Regulator 20 will be better described with reference to
FIG. 3. Injector 22 injects the reducer in line 12. The injector
controls the flow of the reducer. In particular, device 16 controls
injector 22 by varying the injection time of the reducer as a
function of the reducer pressure in line 18. This allows for
precise control of the reducing gas flow and for the reduction of
NOx. Injector 22 is, for instance a needle injector or a membrane
injector, both of which are well known.
[0028] Regulator 20 brings the reducer to a pressure suitable for
injection in line 12. Regulator 20 can reduce the pressure based on
the status of the line 12. Indeed, injector 22 functions at fixed
pressure, and since the reducer pressure fluctuates significantly
because of its gaseous state, the role of regulator 20 is to
regulate the pressure upstream of injector 22. Since the pressure
at the outlet of reservoir 17 can vary from 0 to 300 bar, or more
generally, from 0.1 bar to 30 bar, the regulator stabilizes the
pressure upstream of injector 22. Therefore, the device uses the
regulation of the pressure in conjunction with the opening time of
the injector to define the quantity of supplied gas.
[0029] FIG. 3 shows an example of an embodiment of regulator 20.
The regulator is based on a mechanical principle. Regulator 20
increases the pressure downstream of the regulator if the pressure
is below a pressure threshold for injection in line 12. This
ensures that the reducer pressure is sufficiently high for a
suitable injection, and for a suitable reduction of the toxic
substances present in the exhaust gas. The regulator can comprise a
first chamber 32 in which the reducer enters through the bias of a
channel 34 connected to line 18.
[0030] Regulator 20 further comprises a second chamber 36 that
routes the reducer towards injector 22 through the bias of a
channel 38 connected to line 18. The pressure of the reducer
entering the first chamber is high and the pressure of the reducer
leaving the second chamber is low.
[0031] The line comprises a reducer passage 40 between the first
chamber 32 and the second chamber 36. Passage 40 is closed when the
pressure in the second chamber 36 is above a predetermined
threshold. Passage 40 is open when the pressure in the second
chamber 36 is below the predetermined threshold. Furthermore, if
the pressure in the first chamber becomes higher than the pressure
in the second chamber, the reducer will flow towards the second
chamber through the bias of passage 40. This increases the pressure
in the second chamber and therefore the pressure upstream of
injector 22.
[0032] In more detailed manner, passage 40 extends through a piston
rod 42 that connects the two chambers 32 and 36. Passage 40 is a
routing channel through which the reducer can circulate from one
chamber to the other. Rod 42 extends from one chamber to the other
through a wall 43 of the regulator separating the two chambers. Rod
42 supports a piston head 44. The head 44 is movable in translation
in the second chamber 36. A spring 46 pushes against the head of
the piston 44 in translation in the second chamber 36. Spring 46 is
for instance held in compression between piston head 44 and wall
43.
[0033] When the pressure in the second chamber 36 diminishes and
the pressure in the second chamber 36 drops below the predetermined
threshold, spring 46 pushes the head 44 in the direction of channel
38. This opens the orifice in the extremity of passage 40, situated
in the first chamber 32. Since the pressure is now higher in the
first chamber 32, the reducer passes through the orifice in passage
40 and flows through the orifice at the other end of passage 40,
situated in the second chamber 36. When the pressure in the second
chamber 36 is sufficiently high to counteract the force of spring
46, the pressure in the second chamber 36 pushes the head 44 of the
piston in direction of the wall 43 against spring 46. The orifice
located at the extremity of passage 40, situated in the first
chamber 32, is pressed against the body of regulator 20 and is
closed. The reducer can then no longer circulate from the first
chamber 32 to the second chamber 36.
[0034] Spring 46 is rated to regulate the pressure upstream of the
injector 32 regardless of the pressure upstream of the regulator
20.
[0035] O-rings ensure sealing between piston head 44 and the
regulator body and between piston rod 42 and the regulator body, in
particular wall 43.
[0036] Device 16 further comprises detection instruments 24 for
measuring the pressure downstream of regulator 20. The detection
instruments 24 are used to determine whether the pressure upstream
of injector 22 is too high or too low relative to the pressure
required for injection in line 12. Consequently, the processor
controls the injector as a function of the measured pressure, and
in particular the opening time of the injector.
[0037] Device 16 further comprises detection instruments 26 for
measuring the pressure upstream of regulator 20. The detection
instruments 26 can be used to pilot the reservoir(s) 17. The
information of instruments 26 is also supplied to the processor.
For instance, if the instruments 26 detect a large increase in
pressure on the side of the reservoir(s) 17, this could indicate
that the reservoirs 17 have released too much reducer. Inversely,
if the pressure is too low and beyond a certain threshold, this
could indicate that the reservoir(s) 17 are about to be exhausted.
In case the vehicle comprises several reservoirs 17, for instance
two reservoirs 17, the processor can command a switch of the
reducer supply to the line from one reservoir 17 to another and
signal that one of the reservoirs needs to be changed. In this way,
several reservoirs can be used automatically.
[0038] Pressure detection instruments 24, 26 are also used for
determining the state of the device, namely whether the device 16
is functional or dysfunctional. In other words, detection
instruments 24, 26 detect the proper functioning of regulator 20,
or an anomaly. For instance, instruments 24 can be used for
detecting the proper state of the spring. The information of
instruments 24 is delivered to a processor which determines the
proper functioning of the regulator, and in particular of spring
46. The instruments 24 are connected to the processor, in order to
supply it with information relative to the pressure upstream of
injector 22. Instruments 26 can detect a malfunction of one or more
reservoirs. The processor can send an anomaly signal to inform the
driver of the malfunction.
[0039] Instruments 24 and 26 are for instance pressure switches.
Pressure switches, such as those disclosed in document FR-A-2 275
245, are used for converting a pressure to an electrical signal,
which is sent to the processor. The movements of a membrane in a
chamber, as a function of the pressure in the chamber, open or
close an electrical contact which sends, or stops sending, the
electrical signal. The signal is a binary signal. It can be
envisaged that one or two pressures switches are installed for each
instrument 24 and 26. The advantage of two pressure switches is the
redundancy in case of failure of one pressure switch. Instruments
24 and 26 can also be pressure sensors. One pressure sensor for
each instrument 24, 26 is sufficient because of its
reliability.
[0040] Temperature sensors 30, 31 can be present upstream and/or
downstream of regulator 20. The processor can then also control the
opening time of the injector as a function of the temperature. This
provides a refined measurement of the reducer pressure, which
varies as a function of the temperature in line 38. The temperature
information can also be obtained by calculation, in particular by
means of a model. This method avoids the use of supplementary
sensors.
* * * * *