U.S. patent application number 16/352928 was filed with the patent office on 2020-09-17 for regeneration of automotive exhaust aftertreatment device using diverted boost air during deceleration.
The applicant listed for this patent is Southwest Research Institute. Invention is credited to Daniel C. Bitsis, JR..
Application Number | 20200291842 16/352928 |
Document ID | / |
Family ID | 1000003961295 |
Filed Date | 2020-09-17 |
United States Patent
Application |
20200291842 |
Kind Code |
A1 |
Bitsis, JR.; Daniel C. |
September 17, 2020 |
Regeneration of Automotive Exhaust Aftertreatment Device Using
Diverted Boost Air During Deceleration
Abstract
A method, used with an internal combustion engine, of providing
fresh air for regeneration of an exhaust aftertreatment device. An
air intake diversion line is installed from a point between the
throttle and the compressor to a point upstream of the exhaust
aftertreatment device. A valve on this diversion line is normally
closed. If the engine temperature is above a certain threshold and
if the engine is in a "high load deceleration" state, the valve is
opened, which diverts fresh air to the exhaust aftertreatment
device. The valve is then closed after the pressure in the intake
line is relieved.
Inventors: |
Bitsis, JR.; Daniel C.; (San
Antonio, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Southwest Research Institute |
San Antonio |
TX |
US |
|
|
Family ID: |
1000003961295 |
Appl. No.: |
16/352928 |
Filed: |
March 14, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 3/029 20130101;
F01N 2900/08 20130101; F01N 2270/00 20130101; F01N 9/002 20130101;
F01N 2610/14 20130101; F01N 2560/06 20130101; F01N 2900/1602
20130101; F01N 11/00 20130101; F02M 31/20 20130101 |
International
Class: |
F01N 9/00 20060101
F01N009/00; F01N 3/029 20060101 F01N003/029; F01N 11/00 20060101
F01N011/00; F02M 31/20 20060101 F02M031/20 |
Claims
1. A method, used with an internal combustion engine having an air
intake system with a throttle, an air intake line, and a
compressor, and the engine having at least one exhaust
aftertreatment device on a main exhaust line, of providing fresh
air for regeneration of the exhaust aftertreatment device,
comprising: installing a diversion line from a point between the
throttle and the compressor to a point upstream of the exhaust
aftertreatment device; wherein the diversion line is operable to
carry air from the air intake line to the main exhaust line;
receiving temperature data representing the temperature of the
exhaust aftertreatment device; comparing the temperature data to a
threshold temperature value; receiving high load deceleration data
indicating whether the engine is in a high load deceleration
condition; if the temperature data is above the threshold
temperature value and if the engine is in a high load deceleration
condition, opening a valve on the diversion line; wherein opening
the valve occurs at a time when regeneration of the exhaust
aftertreatment device is occurring or will immediately occur; and,
closing the valve after pressure in the intake line falls to a
desired pressure.
2. The method of claim 1, wherein the compressor is part of a
turbocharger.
3. The method of claim 1, wherein the compressor is part of a
supercharger.
4. The method of claim 1, wherein the air intake line has a cooler,
and the point between the throttle and the compressor is downstream
of the cooler.
5. The method of claim 1, wherein the step of receiving temperature
data is performed by receiving data from a temperature sensor at
the intake of the exhaust aftertreatment device.
6. The method of claim 1, wherein the exhaust aftertreatment device
is a particulate filter.
7. The method of claim 1, wherein the step of receiving high load
deceleration data is performed by receiving data from a sensor that
measures intake manifold pressure.
8. An improved internal combustion engine, the engine having an air
intake system with a throttle, an air intake line, and a
compressor, and the engine having at least one exhaust
aftertreatment device on a main exhaust line, comprising: a
diversion line from a point between the throttle and the compressor
to a point upstream of the exhaust aftertreatment device; wherein
the diversion line is operable to carry air from the air intake
line to the main exhaust line; a valve on the diversion line; a
sensor for acquiring temperature data representing the temperature
of the exhaust aftertreatment device; a sensor for acquiring high
load deceleration data indicating whether the engine is in a high
load deceleration condition; a control unit programmed to receive
the temperature data and the high load deceleration data, and to
perform the following process: to compare the temperature data to a
threshold temperature value; if the temperature data is above the
threshold temperature value, if the engine is in a high load
deceleration condition, and if the exhaust aftertreatment device is
to be or is being regenerated, opening the valve; and, closing the
valve after pressure in the intake line falls to a desired
pressure.
9. The improved internal combustion engine of claim 8, wherein the
compressor is part of a turbocharger.
10. The improved internal combustion engine of claim 8, wherein the
compressor is part of a supercharger.
11. The improved internal combustion engine of claim 8, wherein the
air intake line has a cooler, and the point between the throttle
and the compressor is downstream of the cooler.
12. The improved internal combustion engine of claim 8, wherein the
sensor for acquiring temperature data is a temperature sensor at
the intake of the exhaust aftertreatment device.
13. The improved internal combustion engine of claim 8, wherein the
exhaust aftertreatment device is a particulate filter.
14. The improved internal combustion engine of claim 8, wherein the
sensor for acquiring high load deceleration data is a sensor that
measures intake manifold pressure.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates to internal combustion engines, and
more particularly to regeneration of exhaust aftertreatment
devices.
BACKGROUND OF THE INVENTION
[0002] Exhaust aftertreatment devices such as particulate filters
are known in the art for controlling vehicle engine emissions.
During engine operation, carbon particulates are produced as
byproducts of combustion. These materials are subsequently
collected by the particulate filter. As the carbon particulates
accumulate within the filter, the filter must be regenerated.
[0003] Regeneration is the process of removing accumulated soot or
other emissions material from the exhaust aftertreatment device.
Passive regeneration uses the engine's exhaust heat, sometimes
aided by adding a catalyst aftertreatment device. Active
regeneration introduces very high heat into the exhaust system.
[0004] On-board active regeneration can use a variety of
strategies, mostly directed at increasing temperature of the
exhaust or of the aftertreatment device itself. Examples are engine
management to increase exhaust temperature through late fuel
injection or injection during the exhaust stroke, use of catalysts,
fuel burners downstream the turbocharger, and heating coils or
microwave energy.
[0005] Most regeneration techniques also require additional oxygen
to be available. For example, in the case of a particulate filter,
oxygen assists in oxidation of soot. Various techniques have been
developed to overcome lack of sufficient oxygen during
regeneration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] A more complete understanding of the present embodiments and
advantages thereof may be acquired by referring to the following
description taken in conjunction with the accompanying drawings, in
which like reference numbers indicate like features, and
wherein:
[0007] FIG. 1 illustrates an engine having a conventional
high-pressure relief recirculation line.
[0008] FIG. 2 illustrates an engine having an intake diversion line
to an exhaust aftertreatment device in accordance with the
invention.
[0009] FIG. 3 illustrates a method of using the intake diversion
line of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The following description is directed to regeneration of
exhaust aftertreatment devices, such as a particulate filter, used
in an internal combustion engine. This method is useful for
throttled engines, gasoline or diesel, that also have a
turbocharger or supercharger. The method redirects fresh air to the
aftertreatment device that would otherwise be recirculated. This
fresh air assists in regeneration of the aftertreatment device.
[0011] In turbocharged or supercharged engines that operate with an
intake throttle, the throttle is used to help maintain a desired
air-fuel ratio. Superchargers and turbochargers are referred to
herein collectively as "air boosting devices".
[0012] For purpose of example herein, the exhaust aftertreatment
device to be regenerated is a particulate filter. However, the
method of the invention may be used with any other type of exhaust
aftertreatment device that benefits from fresh air during
regeneration. Other possible aftertreatment devices may be NOx
traps or three-way catalysts.
[0013] In many engine applications, especially those that operate
at stoichiometric conditions, the required intake manifold pressure
may vary from above ambient at full load to below ambient at light
load. In these applications, careful consideration is given to the
air boosting device during a hard "tip out" or "hard deceleration".
During a hard deceleration, the intake throttle is closed and there
is excess pressure in the air intake line between the compressor
and throttle. If not relieved, this pressure will cause compressor
surge, which is a condition where the pressure ratio is high while
the flow is low. This is not only audible but can damage the
compressor and abruptly slow it down.
[0014] FIG. 1 illustrates a conventional internal combustion engine
100 of the type for which the invention is useful. Only those
elements of engine 100 relevant to the invention are specially
described herein, and it is to be assumed that engine 100 has all
the parts of a typical engine.
[0015] A turbocharger 101 has a compressor 101a and turbine 102b.
An exhaust aftertreatment device 102, such as a particulate filter,
is installed downstream the turbine 101b on the engine's main
exhaust line.
[0016] Engine 100 uses a throttle 103 to maintain a desired
air-fuel ratio. As stated in the Background, during certain engine
operating conditions, excess air pressure can arise in the intake
line 106 between the throttle 103 and compressor 101a.
[0017] In a conventional engine, a bypass valve 104 is used to
relieve excess air pressure in the fresh air intake line. When the
valve 104 is open, excess air pressure is recirculated back to the
inlet of the compressor 101a.
[0018] FIG. 2 illustrates an engine 200 having a fresh air
diversion valve 205 in accordance with the invention. Like engine
100, engine 200 has a turbocharger 201, with a compressor 201a and
turbine 202b. It should be noted that the invention is also useful
when the compressor is part of a supercharger rather than a
turbocharger.
[0019] An exhaust aftertreatment device 202, such as a particulate
filter, is installed downstream the turbine 201b on the main
exhaust line.
[0020] A throttle 203 is used to maintain a desired air-fuel ratio.
As with engine 100, during certain engine operating conditions,
engine 200 can experience excess air pressure in the fresh air
intake line 206 between the throttle 203 and compressor 201a.
[0021] In the case of engine 200, a diversion line 204 is installed
between points A and B illustrated in FIG. 2. Point A is between
throttle 203 and compressor 201a. If engine 200 has a charge air
cooler 207, Point A is downstream cooler 207. Point B is between
turbine 201b and aftertreatment device 202. Typically, Point B will
be immediately upstream the aftertreatment device 202.
[0022] A valve 205 controls whether air from the compressor intake
line 206 shall be diverted through diversion line 204. Various
implementations of valve 205 are possible; valve 205 can be
air-actuated or electrically actuated. Valve 205 can be an on/off
valve or can be variable.
[0023] Valve 205 is normally closed. However, as explained below in
connection with FIG. 3, when valve 205 is open, diversion line 204
provides relief for the compressor 201a. At the same time, the
opening of valve 205 adds oxygen to the exhaust upstream of
aftertreatment device 202.
[0024] Engine 200 is further equipped with a control unit 210,
which allows the use of diversion line 204 and valve 205 to be
incorporated into the engine's control strategy. Control unit 210
is assumed to have appropriate hardware and software, programmed in
accordance with the method described herein.
[0025] As explained below in connection with FIG. 3, control unit
210 receives data representing the temperature of the exhaust
aftertreatment device, T(EAD). It also receives data representing
whether the engine is in a "high load deceleration condition" as
defined herein. Control unit 210 stores threshold temperature data,
which it compares to the current temperature values. Control unit
210 then processes all input data to determine whether to generate
a signal to actuate valve 205.
[0026] FIG. 3 illustrates one method of using diversion line 204.
Step 301 is receiving the temperature of the exhaust aftertreatment
device, T(EAD). Referring again to FIG. 2, this temperature data
can be acquired using a sensor at the intake of aftertreatment
device 202. Alternatively, temperature could be implied from data
representing the engine load history.
[0027] Step 303 is determining whether T(EAD) is above a stored
threshold temperature. As stated above, if engine 200 has been
above a certain load for a certain time period, T(EAD) will be
sufficiently high for the oxidation requirements of regeneration.
If so, the method proceeds to Step 305.
[0028] Step 305 determines whether there has been a "high load
deceleration". This occurs after high load operation, when the
vehicle operator suddenly decelerates or reduces the engine load
such that the intake throttle 203 closes. Referring again to FIG.
2, a "high load deceleration" can be determined or implied by a
sensor that measures intake manifold pressure (P) or any pressure
in intake line 206 between throttle 203 and compressor 201a. If the
current pressure target is above ambient and the next pressure
target is below ambient, then throttle 203 closes, and a high load
deceleration condition is assumed to exist.
[0029] In Step 307, if T(EAD) is above the desired threshold and if
there is a high load deceleration, control unit 210 opens valve
205. As a result, a burst of fresh air is sent to the exhaust
aftertreatment device 202. Where aftertreatment device 202 is a
particulate filter, this burst of fresh air aids in soot
oxidation.
[0030] The opening of valve 205 is further timed to occur during
regeneration of the exhaust aftertreatment device. The valve
opening may coincide with the beginning of regeneration or it may
occur at some other time during regeneration. This timing will
vary, depending on the regeneration requirements, such as a need
for increased oxygen in the exhaust entering the aftertreatment
device.
[0031] The duration of the opening of valve 205 may vary depending
on regeneration requirements of the exhaust aftertreatment device
but is no longer than required to relieve the high intake pressure.
Then, valve 205 is closed.
[0032] It is not expected that the method of FIG. 3 would be the
sole method for regenerating an aftertreatment device, but it could
be an integral part of the overall strategy.
* * * * *