U.S. patent application number 13/043060 was filed with the patent office on 2012-09-13 for filter cleaning with an engine idle bump.
Invention is credited to Benjamin P. Koestler.
Application Number | 20120227379 13/043060 |
Document ID | / |
Family ID | 46787400 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120227379 |
Kind Code |
A1 |
Koestler; Benjamin P. |
September 13, 2012 |
Filter Cleaning With An Engine Idle Bump
Abstract
Disclosed is a method of filter regeneration employing an
automatic increase in the minimum speed of an engine when a vehicle
is in a parked state. The filter regeneration until the operator
cancels it or filter regeneration is determined to be complete.
Inventors: |
Koestler; Benjamin P.;
(Asbury, IA) |
Family ID: |
46787400 |
Appl. No.: |
13/043060 |
Filed: |
March 8, 2011 |
Current U.S.
Class: |
60/274 ;
60/311 |
Current CPC
Class: |
F01N 3/023 20130101;
F01N 2590/08 20130101 |
Class at
Publication: |
60/274 ;
60/311 |
International
Class: |
F01N 3/023 20060101
F01N003/023 |
Claims
1. A method of filter regeneration for a work vehicle having an
engine, a park brake capable of being engaged or disengaged, a
throttle capable of being engaged or not engaged, the method
comprising: a. monitoring engine speed with an engine speed
detector; b. monitoring a status of the park brake with a park
brake sensor; c. monitoring a status of the throttle with a
throttle sensor; and d. automatically latching the engine speed to
a predetermined engine speed sufficient for filter regeneration
when the engine is running, the park brake is engaged, and the
throttle is not engaged.
2. The method of claim 1, further comprising continuing the
latching of the engine speed to the predetermined engine speed
until the filter regeneration is complete.
3. The method of claim 1, further comprising continuing the
latching of the engine speed to the predetermined engine speed
until an operator cancels the filter regeneration.
4. A method of filter regeneration for a work vehicle having an
ignition capable of being on and off, a filter capable of
accumulating soot, an engine capable of being started and not
started, a temperature sensor for detecting a temperature of the
exhaust gas exiting the engine, a park brake capable of being
engaged and disengaged, a throttle capable of being engaged and not
engaged, the method comprising: a. monitoring a status of the park
brake with a park brake sensor; b. monitoring a status of the
throttle with a throttle sensor; c. monitoring a temperature of the
exhaust gas exiting the engine with a temperature sensor; d.
monitoring an engine speed with an engine speed sensor, the engine
speed being at standby idle when the status of the throttle is not
engaged; e. calculating a soot level for the filter; and f.
automatically latching the engine speed to a predetermined engine
speed for raising a temperature of the exhaust gas exiting the
engine to at least a predetermined temperature sufficient for
filter regeneration only if: (1) the engine is started, (2) the
park brake sensor detects a status of engaged; (3) the engine is at
idle standby; (4) the temperature sensor detects an exhaust gas
temperature below a predetermined threshold temperature; and the
calculated soot level is high.
5. The method of claim 4, further comprising continuing the
latching of the engine speed to the predetermined engine speed
until the filter regeneration is complete.
6. The method of claim 4, further comprising continuing the
latching of the engine speed to the predetermined engine speed
until an operator cancels the filter regeneration.
7. A system for exhaust filter regeneration in a work vehicle
having an exhaust filter capable of accumulating soot at levels
varying from negligible to high, comprising: an engine capable of
being started and not started; an engine speed sensor for detecting
a speed of the engine; a throttle capable of being engaged and not
engaged; a throttle sensor for detecting whether the throttle is
engaged or not engaged, the engine being at standby idle when the
throttle is not engaged and filter regeneration is not enabled; a
temperature sensor for detecting the temperature of the exhaust gas
as it exits the engine; a transmission having a neutral setting,
and a non-neutral setting; a transmission sensor for detecting the
setting of the transmission; a park brake capable of being engaged
and disengaged; a park brake sensor capable of detecting whether
the park brake is engaged or disengaged; an ignition capable of
being on and off; at least one controller for controlling functions
of the engine, for detecting a filter soot level and for
controlling functions of the vehicle; and a timer for timing a
duration of an event, the at least one controller initiating an
increase in engine speed to a first predetermined level only when:
(1) the ignition is on, (2) the engine is running, (3) the engine
is at standby idle, (4) the park brake is engaged, (5) the
transmission sensor detects a neutral setting, (6) the temperature
sensor detects an exhaust gas temperature lower than a
predetermined temperature required for filter regeneration, and the
detected filter soot level is high.
8. The system of claim 7, wherein the controller latches the engine
speed to a second predetermined engine speed for filter
regeneration upon the engine achieving the first predetermined
engine speed.
9. The system of claim 8, wherein the controller continues to latch
the engine speed at the second predetermined engine speed until the
controller determines filter regeneration is complete.
10. The system of claim 8, wherein the at least one controller
continues to latch the engine speed at the second predetermined
engine speed until the operator cancels the filter regeneration by
at least one of turning the ignition off or instructing the at
least one controller to cancel the filter regeneration.
11. The system of claim 8, wherein the at least one controller
comprises an engine control unit for controlling functions of the
engine and a vehicle controller unit for controlling functions of
the vehicle and temporarily controlling engine speed when
initiating filter regeneration.
Description
FIELD OF THE INVENTION
[0001] This invention relates to emission control systems in motor
vehicles powered by internal combustion engines and, more
particularly, vehicles powered by diesel engines with exhaust gas
treatment devices requiring regeneration.
BACKGROUND OF THE INVENTION
[0002] Diesel particulate filters (DPFs) form a known part of
certain diesel engine exhaust gas systems trapping significant
amounts of pollutants such as hydrocarbons, carbon monoxide and ash
as the exhaust gas travels through them, i.e., the DPFs. Engine
efficiency may decrease as the amount of pollutants the DPF has
entrapped increases. It is, therefore, incumbent on the
operator/owner of the vehicle to at least periodically regenerate,
i.e., clean the DPF.
[0003] DPFs may be regenerated by raising the temperature of their
internal temperatures to a temperature suitable for flashing and
flushing the pollutants, i.e., cleaning the DPFs. Such a rise in
temperature may be accomplished by increasing the temperature of
the exhaust gases passing through the DPFs. In cold conditions, a
rise in exhaust gas temperatures may be accomplished by an
increased load on the engine. Increasing the volume of exhaust gas
throughput may enhance the flushing of such pollutants. There are a
variety of methods used to increase the temperature of gases
flowing through the DPFs, many of which are complex and/or
cumbersome.
SUMMARY OF THE INVENTION
[0004] Disclosed is a method of increasing exhaust gas temperatures
to threshold temperatures for DPF regeneration via automatic
increase in engine idle speed to a predetermined engine speed at
high soot levels until regeneration is complete, i.e., the detected
soot level is low or 0. This may be especially helpful in colder
climates (temperatures lower than 0.degree. C.) where an operator
is likely to want to leave a vehicle running for an extended period
of time, i.e., for example, over a weekend.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is an illustration of a vehicle which may make use of
the invention;
[0006] FIG. 2 is a schematic of an engine and control system;
[0007] FIG. 3 is an alternative view of the engine and control
system with controller 100; and
[0008] FIG. 4 is a flowchart illustrating the workings of an
embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0009] FIG. 1 is a side view of a work vehicle, i.e., a loader 10
having an operator cab 20; wheels 30 for powered movement along the
ground; and an engine 40. Such a work vehicle, as well as others,
may be suitable for use of the invention.
[0010] FIG. 2 is a schematic of parts of the vehicle involved in an
exemplary embodiment of the invention. Illustrated is a vehicle
controller unit ("VCU") 15 which controls various functions of the
vehicle 10; an engine 40; an engine speed sensor 40a; an exhaust
40b providing a route for engine exhaust gases; a throttle 41
capable of being engaged and not engaged; a throttle position
sensor 41a capable of detecting whether the throttle 41 is engaged
or not engaged; an engine oil pressure sensor 42a; an engine
coolant temperature sensor 43; an engine coolant level sensor 44;
an engine controller unit ("ECU") 45 capable of controlling the
functions of the engine 40; a transmission 50 capable of being in a
forward, a reverse, or a neutral gear; a transmission gear sensor
50a; a park brake 55 capable of being engaged and disengaged; a
park brake sensor 55a capable of detecting if the park brake 55 is
engaged or disengaged; an ignition 60 having an on position and an
off position through which the vehicle may be powered by an
electrical power source 70 which may be a battery, an alternator or
some other device when the ignition is in a first position and the
vehicle 10 is shutdown when the ignition 60 is in a second
position; a diesel particulate filter ("DPF") 80; an exhaust gas
temperature sensor 81; a fuel dosing injector 82; a diesel
oxidation catalyst ("DOC") 83; and a timer 90 by which the ECU 45
and the VCU 15 measure time passed.
[0011] In this exemplary embodiment, during a regeneration of the
DPF 80, the exhaust gas exiting the engine 40 is dosed with fuel
via the fuel dosing injector 82 as it travels to the DOC 83 where
its temperature may be raised, via additional burning, to
approximately 575.degree. C. prior to entering the DPF 80. This
high temperature may be required to effect regeneration of the DPF
80. In order to attain this end temperature it may be necessary to
have the exhaust gas at a temperature of at least 275.degree. C. as
it exits the engine 40. Increases in engine speed may have the
effect of raising exhaust gas temperatures. In cold climates, the
inventor has determined that, for this exemplary embodiment, a
minimum engine speed of 1200 rpm may constitute an engine load
sufficient to raise the exhaust gas temperature to the minimum of
275.degree. C. as the exhaust gas exits the engine 40.
[0012] FIG. 3 illustrates how the sensors, the timer 95 and a
warning device 96 may communicate with the controller unit
combination 100. In this exemplary embodiment the warning device 96
may be a monitor, audible sound generator or some other device
which may include a switch and may, among other things, indicate:
the vehicle 10 is ready for idle bump regeneration of the DPF 80;
the vehicle 10 will/has started idle bump regeneration of the DPF
80; idle bump regeneration of the DPF 80 has been completed; or
idle bump regeneration of the DPF 80 has been canceled by the
operator.
[0013] The vehicle 10 is considered in a parked state, i.e., a
state suitable for idle bump, when the following conditions exist:
(1) the ignition 60 is on; (2) the engine 40 is running; (3) the
transmission 50 is in a neutral gear; (4) the park brake 55 is
engaged; (5) the engine speed is at standby idle, i.e., the
throttle 42 is not engaged; (6) the DPF soot level is high; and (7)
alternate regeneration methods are not active. The ECU 45 may
determine soot level by: monitoring exhaust gas temperatures over
time and using a lookup table to calculate the difference between
soot accumulated over time and soot burned or oxidized over time;
or simply as a function of the accumulated time over which the
engine has been running based on experiential data. Times over
which soot is accumulated may be times over which exhaust gas
temperatures are lower than a threshold temperature as it exits the
engine. Times over which soot is burned may be times over which
exhaust gas temperatures are at least equal to the threshold
temperature as it exits the engine. Whatever the method used to
make the determination, it is the ECU 45 that determines the soot
level in this exemplary embodiment. The VCU 15 may direct the
regeneration of the DPF 80 via idle bump, i.e., an increase in
engine speed, when the vehicle 10 is in the parked state. Unless
the operator cancels regeneration, idle bump regeneration may
continue until regeneration is complete even if the operator begins
work operations, taking the vehicle out of the parked state. An
exemplary idle bump regeneration process will now be described
below.
[0014] The exemplary idle bump regeneration process begins when the
vehicle is in a parked state and the ECU 45, upon determining that
the DPF soot level is high, signals the VCU 15 to begin the idle
bump process for regenerating the DPF 80. The VCU 15 then takes
control of the engine speed command and requests an engine speed
increase to a first predetermined engine speed which, in this
exemplary embodiment, may be 1250 rpm. Once the first predetermined
engine speed is achieved, the VCU 15 may release control of the
engine and allow the ECU 45 to set a second predetermined engine
speed, which, in this exemplary embodiment, may be 1200 rpm, below
which the engine will not be allowed to go, i.e., to latch the
engine speed at the second predetermined engine speed. The engine
speed may be latched at 1200 rpm until the regeneration of the DPF
80 is complete or the operator cancels the process via a switch
which may be located on the warning device 96 or by shutting down
the vehicle 10.
[0015] FIG. 4 illustrates a flowchart that may represent the manner
in which this exemplary embodiment works. As illustrated in FIG. 4,
the entire process may begin at step 100 with the ignition 11 and
the engine 40 on. Once the ECU 45 determines that the soot level is
at a predetermined level, i.e., that it is high at step 110, and
the VCU 15 determines that the vehicle is in a parked state, i.e.,
the park brake sensor 55a indicates that the park brake 55 is
engaged at step 120; the transmission sensor 50a indicates that the
transmission 50 is in a neutral gear at step 130; and the engine
speed is at standby idle, i.e., the throttle position sensor 41a
indicates the throttle 40 is not engaged at step 140, the VCU 15
takes control of engine speed commands at step 150 and, if idle
bump is not canceled by the operator at step 151, increases engine
speed, at step 152, to the first predetermined engine speed which,
in this exemplary embodiment, may be a speed equal to or greater
than 1250 rpm. Once the first predetermined engine speed is
achieved at step 152, at step 160, the warning device 96 informs
the operator that engine idle speed has been increased, the VCU 15
releases control of engine speed commands and signals the ECU 45 to
latch the engine speed to a second predetermined engine speed
whereupon, at step 165, the ECU 45 latches the engine speed at the
second predetermined engine speed which, in this exemplary
embodiment may be 1200 rpm. If the idle bump is not canceled by the
operator, at step 170, the ECU 45 continues with the latch at step
180 until the ECU 45 determines that regeneration of the DPF 80 is
complete, at which time, the ECU 45 cancels the idle bump
regeneration, i.e., unlatches the second predetermined engine speed
and allows the engine speed to return to the standby idle setting.
The operator may cancel idle bump regeneration at any time, i.e.,
at step 151 or 170, by shutting down the vehicle 10 or manipulation
of a mechanical or electronic switch which may be located on the
warning device 96. Unless the operator cancels idle bump
regeneration, it will continue until regeneration is complete.
[0016] Having described the preferred embodiment, it will become
apparent that various modifications can be made without departing
from the scope of the invention as defined in the accompanying
claims.
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