U.S. patent application number 09/829090 was filed with the patent office on 2001-08-30 for controller and storage medium for detecting cold engine operation.
This patent application is currently assigned to DETROIT DIESEL CORPORATION. Invention is credited to Thomas, Eric D..
Application Number | 20010018632 09/829090 |
Document ID | / |
Family ID | 23081913 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010018632 |
Kind Code |
A1 |
Thomas, Eric D. |
August 30, 2001 |
Controller and storage medium for detecting cold engine
operation
Abstract
An engine controller and computer readable storage medium for
detecting cold engine operation include determining at least two
fluid temperatures and providing an output signal based on the at
least two temperatures. Preferably, an engine coolant temperature,
an intercooler temperature, and an engine air temperature are
determined via appropriate temperature sensors. In one embodiment,
the cold engine output signal is activated or asserted if any one
of the at least two fluid temperatures is below a corresponding
temperature threshold. The cold engine output signal is deactivated
when all of the fluid temperatures are above corresponding
temperature thresholds (plus hysteresis where applicable). An
optional user-selectable parameter provides for actuation of the
cold engine output only during idle. The cold engine output signal
may be used to control various accessories including coolant
heating systems, shutters, or the like. Additional parasitic loads
or an exhaust brake may be actuated to increase combustion
temperatures by increasing engine load to reduce or eliminate white
smoke.
Inventors: |
Thomas, Eric D.; (Canton,
MI) |
Correspondence
Address: |
DAVID S. BIR
Brooks & Kushman P.C.
22nd Floor
1000 Town Center
Southfield
MI
48075-1351
US
|
Assignee: |
DETROIT DIESEL CORPORATION
Detroit
MI
|
Family ID: |
23081913 |
Appl. No.: |
09/829090 |
Filed: |
April 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09829090 |
Apr 9, 2001 |
|
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09282526 |
Mar 31, 1999 |
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6243642 |
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Current U.S.
Class: |
701/113 ;
123/491; 701/115 |
Current CPC
Class: |
F01P 2025/13 20130101;
F02B 29/0493 20130101; F02B 29/0443 20130101; F01P 7/048 20130101;
F01P 7/164 20130101; Y02T 10/12 20130101; F01P 2025/42 20130101;
F01P 2025/08 20130101; F01P 2060/02 20130101; F02D 41/064 20130101;
F01P 7/167 20130101; F01P 7/12 20130101 |
Class at
Publication: |
701/113 ;
701/115; 123/491 |
International
Class: |
G06G 007/70; G06F
019/00; F02M 051/00 |
Claims
What is claimed is:
1. A computer readable storage medium having stored data
representing instructions for detecting cold engine operation of an
internal combustion engine including a plurality of sensors for
detecting a corresponding plurality of fluid temperatures in
communication with an engine control module having stored
temperature thresholds associated with the fluid temperatures, the
computer readable storage medium comprising: instructions for
determining a plurality of fluid temperatures using at least one of
the plurality of sensors; instructions for comparing each of the
plurality of fluid temperatures to a corresponding fluid
temperature threshold; and instructions for generating a cold
engine output signal indicative of cold engine operation when any
one of the plurality of fluid temperatures is below its
corresponding fluid temperature threshold.
2. The computer readable storage medium of claim 1 wherein the
instructions for comparing a plurality of fluid temperatures
includes at least two fluid temperatures selected from: coolant
temperature, intercooler temperature, and engine air
temperature.
3. The computer readable storage medium of claim 1 wherein the
instructions for comparing comprise instructions for comparing each
of the plurality of fluid temperatures to a corresponding fluid
temperature plus a hysteresis term to prevent rapid oscillation of
the cold engine output signal.
4. The computer readable storage medium of claim 1 wherein the
plurality of fluid temperatures comprises engine coolant
temperature, intercooler temperature, and engine air
temperature.
5. An engine controller including a computer readable storage
medium having stored data representing instructions for detecting
cold engine operation of an internal combustion engine including a
plurality of sensors for detecting a corresponding plurality of
fluid temperatures in communication with an engine control module
having stored temperature thresholds associated with the fluid
temperatures, the engine controller determining a plurality of
fluid temperatures using at least one of the plurality of sensors,
comparing each of the plurality of fluid temperatures to a
corresponding fluid temperature threshold, and generating a cold
engine output signal until every one of the plurality of fluid
temperatures is above its corresponding fluid temperature
threshold.
6. The engine controller of claim 5 wherein the plurality of fluid
temperatures includes at least two fluid temperatures selected
from: coolant temperature, intercooler temperature, and engine air
temperature.
7. The engine controller of claim 5 wherein the controller compares
each of the plurality of fluid temperatures to a corresponding
fluid temperature plus a hysteresis term to prevent rapid
oscillation of the cold engine output signal.
8. The engine controller of claim 5 wherein the plurality of fluid
temperatures comprises engine coolant temperature, intercooler
temperature, and engine air temperature.
9. The engine controller of claim 5 wherein the controller is
connected to at least one accessory to control the accessory based
on the output signal.
10. The engine controller of claim 5 wherein the controller
activates at least one auxiliary device using the output signal to
increase combustion temperatures within the engine by increasing
engine load.
11. The engine controller of claim 5 wherein the controller
determines whether the engine is idling and generates the output
signal only while the engine is idling.
12. A system for detecting cold engine operation and providing a
cold engine output signal for use in engine or vehicle control, the
system comprising: a first temperature sensor for measuring a
corresponding first engine fluid operating temperature; a second
temperature sensor for measuring a second engine fluid operating
temperature; and a controller in communication with the first and
second temperature sensorssor, the controller including
instructions for comparing at least two temperatures to
corresponding programmable thresholds and generating a cold engine
output signal when any of the temperatures is below its
corresponding threshold.
13. The system of claim 12 wherein the first and second sensors are
selected from an engine coolant sensor, an intercooler sensor, and
an engine air sensor.
14. The system of claim 12 wherein the controller includes
instructions for determining whether the engine is idling and
generating the output signal only while the engine is idling.
15. The system of claim 12 further comprising: an auxiliary device
coupled to the engine, wherein the output signal controls
activation of the auxiliary device.
16. The system of claim 12 wherein the first and second sensors
comprise an engine coolant sensor and an air temperature sensor,
the system further comprising: an intercooler temperature sensor in
communication with the controller, wherein the controller includes
instructions for generating the output signal until the engine
coolant sensor, the air temperature sensor, and the intercooler
temperature sensor are above corresponding temperature thresholds.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S. Ser.
No. 09/282,526 filed Mar. 31, 1999, now U.S. Pat. No. ______, the
disclosure of which is hereby incorporated by reference in its
entirety.
TECHNICAL FIELD
[0002] The present invention relates to a system and method for
detecting a cold engine state using a plurality of engine
temperatures.
BACKGROUND ART
[0003] In the control of internal combustion engines, the
conventional practice utilizes electronic control units, volatile
and non-volatile memory, input and output driver circuitry, and a
processor capable of executing a stored instruction set, to control
the various functions of the engine and its associated systems. A
particular electronic control unit communicates with numerous
sensors, actuators, and other control units necessary to effect
various control and information functions of the engine and/or
vehicle.
[0004] Various sensors are used to detect engine operating
parameters which may affect control of the engine and/or vehicle.
However, many engine operating parameters or conditions are not
directly measured or sensed due to the associated cost and/or
availability of suitable sensors relative to the perceivable
improvement in engine control. These parameters or conditions may
be sensed or measured indirectly by sensing a related process or
parameter using other sensors, or may be calculated or inferred.
For example, torque sensors, while available, are not often used in
vehicular applications. Likewise, it may be desirable to determine
peak combustion temperature or pressure to improve the efficiency
and reduce emissions related to the combustion process. As is
known, lower than optimal combustion temperatures may result in
white smoke while higher combustion temperatures result in
increased production of oxides of nitrogen, and may result in
engine damage if excessive. However, the harsh environment present
within the cylinders is generally not amenable to temperature
and/or pressure sensors for production use.
[0005] Temperature sensors are commonly used to detect the
temperature of various engine and/or vehicle fluids (including air)
to control associated engine components, including valves, heaters,
shutters, and various other mechanisms. As is known, ambient and
operating temperature variations may present a number of challenges
in controlling the engine. Temperature-related complications may
include fuel coagulation, insufficient coolant circulation, and
increased exhaust emissions, among others. Conventional engine
systems use the engine coolant temperature or engine oil
temperature to activate various engine mechanisms in an effort to
improve engine performance. However, a single fluid temperature
measurement is not necessarily indicative of the current engine
operating conditions which may be used to control one or more
engine and/or vehicle devices. As such, it would be desirable to
provide a system and method for detecting a cold engine based on
signals from a plurality of engine temperature sensors.
DISCLOSURE OF INVENTION
[0006] It is therefore an object of the present invention to
provide a method and system for detecting cold engine operation
based on a plurality of engine fluid temperatures.
[0007] Another object of the present invention is to provide a
system and method for detecting cold engine operation based on at
least two fluid temperatures selected form the group including
coolant temperature, intercooler temperature, and engine air
temperature.
[0008] Another object of the present invention is to provide a
system and method for providing a signal indicating cold engine
operation only while the engine is idling.
[0009] An additional object of the present invention is to provide
a cold engine output signal used to control one or more auxiliary
devices based on a plurality of engine fluid temperatures.
[0010] A further object of the present invention is to provide a
system and method for increasing combustion temperature when cold
engine operation is detected by increasing parasitic loads on the
engine.
[0011] A still further object of the present invention is to reduce
or eliminate white smoke by activating one or more auxiliary
devices to increase engine power resulting in increased combustion
temperatures when cold engine operation is detected.
[0012] Yet another object of the present invention is to provide a
customer configurable cold engine output signal based on a
plurality of fluid temperatures.
[0013] A further object of the present invention is to provide a
cold engine output signal based on a plurality of fluid
temperatures each having corresponding temperature thresholds which
can be used to adjust the sensitivity of the signal to any one or
more of the constituent fluid temperatures.
[0014] In carrying out the above objects and other objects and
features of the present invention an engine controller and computer
readable storage medium include instructions for detecting cold
engine operation and providing a cold engine output signal for use
in engine and/or vehicle control by determining at least two fluid
temperatures and providing an output signal based on the at least
two temperatures. Preferably, an engine coolant temperature, an
intercooler temperature, and an engine air temperature are
determined via appropriate temperature sensors. In one embodiment,
the cold engine output signal is activated or asserted if any one
of the at least two fluid temperatures is below a corresponding
temperature threshold. The cold engine output signal is deactivated
when all of the fluid temperatures are above corresponding
temperature thresholds (with appropriate hysteresis). An optional
user-selectable parameter provides for actuation of the cold engine
output only during idle.
[0015] A system for detecting cold engine operation and providing a
cold engine output signal for use in engine control includes a
plurality of engine temperature sensors for providing an indication
of corresponding fluid temperatures. Preferably, the temperature
sensors include an engine coolant temperature sensor for measuring
an engine coolant temperature, an intercooler temperature sensor
for measuring an intercooler temperature, and an engine air
temperature sensor for measuring an engine air temperature. The
system also includes a microprocessor in communication with the
temperature sensors for determining whether at least one of the
temperatures is below a corresponding temperature threshold. The
electronic control unit includes control logic for generating a
cold engine output signal if any of the fluid temperatures is below
its corresponding temperature threshold. The electronic control
unit also includes control logic for deactivating or de-energizing
the cold engine output signal when all of the fluid temperatures
are above their corresponding temperature thresholds. Optional
control logic activates the cold engine output only when a cold
engine condition is detected and the idle governor is active, i.e.
the engine is idling.
[0016] The advantages accruing to the present invention are
numerous. For example, the present invention enables the engine
controller to more accurately detect cold engine operation to
activate various engine and/or vehicle mechanisms based on the cold
engine status. The present invention may be used to reduce white
smoke caused by lower than desired combustion temperatures by
detecting cold engine operation and controlling auxiliary devices
to increase engine load to increase combustion temperatures.
Multiple temperature sensors with corresponding programmable
thresholds provide increased control versatility by providing a
system which can activate cold engine start mechanisms such as
coolant heating systems, extra parasitic loads, shutters or exhaust
(engine) brakes. Independently selectable temperature thresholds or
limits may be used to adjust the response of the cold engine output
based on one or more of the constituent fluid temperatures.
[0017] The above objects and other objects, features, and
advantages of the present invention are readily apparent from the
following detailed description of the best mode for carrying out
the invention when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a schematic diagram of one embodiment for a cold
engine detection system based on engine coolant temperature,
intercooler temperature, and engine air temperature according to
the present invention; and
[0019] FIG. 2 is a block diagram illustrating operation of a system
or method according to the present invention for detecting a cold
engine state, and generating a cold engine output signal.
BEST MODE FOR CARRYING OUT THE INVENTION
[0020] Referring now to FIG. 1, a system for detecting cold engine
operation based on at least two fluid temperatures according to the
present invention is shown. Preferably, the at least two fluid
temperatures are selected and may include the coolant temperature,
intercooler temperature, and engine air temperature. The system,
generally indicated by reference numeral 10, includes an engine 12
having a plurality of cylinders. In a preferred embodiment, engine
12 is a multi-cylinder compression ignition internal combustion
engine, such as a four, six, eight, twelve, sixteen or twenty-four
cylinder diesel engine, for example. The system further includes an
intercooler 20 with an associated intercooler heat exchanger 14, an
engine coolant heat exchanger 16, and a coolant surge tank 18.
While an air-to-fluid charge cooling system is illustrated in FIG.
1, the present invention is equally applicable to an air-to-air
charge cooling system.
[0021] As also illustrated in FIG. 1, system 10 includes an engine
coolant temperature sensor 22, an engine air temperature sensor 24,
an intercooler temperature sensor 26, an engine water pump 28, an
intercooler water pump 30, and an engine oil cooler 32.
[0022] Intercooler 20 extracts heat from charge air which is
compressed (and thereby heated) by a conventional turbocharger (not
shown). An appropriate cooling fluid or coolant absorbs heat from
intercooler 20 and is circulated through intercooler heat exchanger
14 via intercooler water pump 30. Engine coolant heat exchanger 16
removes heat from the engine coolant using a conventional heat
exchanger configuration as well known in the art. Coolant surge
tank 18 is connected to both the intercooler heat exchanger 14 and
engine coolant heat exchanger 16 via corresponding fill lines to
maintain a desired fluid level within the system while providing
overflow protection. Preferalbly, a temperature transducer 22
measures the engine coolant temperature as the coolant exits the
engine. This location typically exhibits the maximum temperature of
the engine coolant temperature relative to all other points within
the cooling circuit.
[0023] Engine air temperature transducer 24 measures temperature of
the air being drawn into the intake manifold. Intercooler
temperature transducer 26 measures the temperature of the
intercooler coolant as it exits intercooler 20. This point in the
intercooler cooling circuit generally represents the maximum
intercooler coolant temperature within the circuit. Engine coolant
water pump 28 circulates the engine coolant through the engine
block and through the engine coolant heat exchanger 16. Similarly,
intercooler water pump 30 circulates the coolant through the
intercooler lines connecting intercooler heat exchanger 14 with the
intercooler heat exchanger 20.
[0024] System 10 may also includes various other sensors 44 for
generating signals indicative of corresponding engine conditions or
parameters of engine 12 or of the vehicle (not shown). Sensors 44
may include appropriate sensors for providing signals indicative of
boost pressure, oil-temperature, oil pressure, oil level, fuel
pressure, vehicle speed, and coolant level. Likewise, various
switches connected to an operator interface may be provided to
select various optional engine operating modes including stop
engine override, selection and setting of cruise control, and the
like. Engine and/or vehicle operating parameters or conditions may
also be calculated, determined, or inferred based on one or more of
the sensed parameters for operating conditions indicated by sensors
44.
[0025] Sensors 44 are in electrical communication with a controller
46 via input ports and/or conditioning circuitry 48. A preferred
embodiment of controller 46 includes a DDEC controller available
from Detroit Diesel Corporation, Detroit, Mich. Various other
features of this controller are described in detail in U.S. Pat.
Nos. 5,477,827 and 5,445,128, the disclosures of which are hereby
incorporated by reference in their entirety. Controller 46
preferably includes a microprocessor 50 in communication with
various computer readable storage media 52 via data and control bus
54. Computer readable storage media 52 may include any number of
known devices which function as a read only memory (ROM) 56, random
access memory (RAM) 58, keep alive memory (KAM) 60 and the like.
The computer readable storage media may be implemented by any of a
number of known physical devices capable of storing data
representing instructions executable via a computer such as
controller 46. Known devices may include but are not limited to,
PROM, EPROM, EEPROM, flash memory, and the like in addition to
magnetic, optical, and combination media capable of temporary or
permanent data storage.
[0026] Computer readable storage media 52 include data representing
program instructions (software), calibrations, operating variables
and the like used in conjunction with associated hardware to effect
control of various systems and subsystems of the vehicle, such as
engine 12. Controller 46 receives signals from sensors 44 via input
ports 48 and generates output signals which may be provided to
various actuators 62 and/or components via output ports 54. Signals
may also be provided to a display device 66 which may include
various indicators such as lights 68 to communicate information
relative to system operation to the operator of the vehicle. Of
course, alphanumeric, audio, video, or other displays or indicators
may be utilized if desired.
[0027] With continuing reference to FIG. 1, control logic
implemented by controller 46 and associated hardware and/or
software is used to detect cold engine operation according to the
present invention. In a preferred embodiment, the control logic
implemented by controller 46 detects cold engine operation based on
at least two fluid temperatures and corresponding programmable or
selectable temperature thresholds. Preferably, controller 46
determines whether the coolant temperature as indicated by the
coolant temperature sensor or transducer 22, the engine air
temperature as indicated by engine air temperature sensor or
transducer 24, and the intercooler temperature as indicated by the
inter cooler temperature sensor or transducer 26 have exceeded
their respective predefined temperature thresholds. As will be
appreciated by one of ordinary skill in the art, control logic
according to the present invention is preferably implemented by a
programmed microprocessor operating as described in detail below.
However, various alternative hardware and/or software may be used
to implement the control logic without departing from the spirit or
scope of the present invention.
[0028] A data, diagnostics, and programming interface 70 may be
selectively connected to controller 46 via a connector 72 to
exchange various information between controller 46 and the operator
and/or service personnel. Interface 70 may be used to change values
within the computer readable storage media 52, such as
configuration settings, calibration variables, look-up table
values, control logic, and the like. For example, interface 70 may
be used to program or select temperature thresholds for each of the
monitored fluid temperatures to detect cold engine operation
according to the present invention.
[0029] In operation, engine coolant temperature transducer 22
measures the engine coolant temperature, engine air temperature
transducer 24 measures the intake manifold air temperature, and
intercooler temperature transducer 26 measures the intercooler
coolant temperature. Controller 46 determines whether the engine
coolant temperature threshold, the air temperature threshold and
the intercooler coolant temperature threshold have been exceeded.
If controller 46 determines that the engine coolant temperature,
engine air temperature or the intercooler coolant temperature are
below their associated temperature thresholds, controller 46
activates (or energizes or asserts) the cold engine output signal
which is preferably a digital or binary output signal which may be
asserted high or low depending upon the particular application. The
cold engine output signal is provided by controller 46 to actuate
various mechanisms based on cold engine operation. Such mechanisms
or devices may include coolant heating systems, extra parasitic
loads, shutters, or exhaust brakes, for example. The temperature
thresholds for the monitored fluid temperatures are preferably
calibrated independently such that the sensitivity of the cold
engine operation signal to any one or more of the parameters may be
adjusted depending on the particular application.
[0030] In a preferred embodiment of the present invention, cold
engine operation is indicated when any one of the monitored fluid
temperatures is below its associated temperature threshold. For
example, if any one of the engine coolant temperature, the
intercooler temperature or the engine air temperature is below its
associated threshold, cold engine operation is indicated and an
appropriate signal is provided. While calibrations will vary by
application, typical threshold values for coolant temperature,
intercooler temperature, and engine air temperature are -5.degree.
F., 10.degree. F., and 32.degree. F., respectively. However, in one
embodiment of the present invention, each of the temperature
thresholds may be set to any value between -40.degree. F. and
215.degree. F. since one byte of memory is allocated to each
calibration and scaled accordingly. To prevent rapid oscillation of
the cold engine operation signal when the temperatures are near
their threshold, a hysteresis value is provided. Preferably, a
common hysteresis parameter is used for all of the monitored fluid
temperatures although individual hysteresis parameters could be
provided if desired based on the relative time response of the
temperature variations of the monitored fluid. In one embodiment of
the present invention, the hysteresis value is allocated a single
byte of memory and may be set to any value between 0 and 255. In
this embodiment, when controller 46 determines that all of the
monitored fluid temperatures are above their corresponding
thresholds plus the hysteresis term, cold engine operation is no
longer indicated and the output is not asserted. As indicated
above, this output may be used to control various engine or vehicle
accessories. Controller 46 also determines whether any one of the
monitored fluid temperatures is below its corresponding temperature
threshold activate the cold engine output.
[0031] Referring now to FIG. 2, a flow chart illustrating operation
of a system or method for detecting cold engine operation according
to the present invention is shown. As will be appreciated by one of
ordinary skill in the art, the flow chart represents control logic
which may be implemented or effected in hardware, software, or a
combination of hardware and software. The various functions are
preferably effected by a programmed microprocessor such as the DDEC
controller, but may include one or more functions implemented by
dedicated electric, electronic, or integrated circuits. As will
also be appreciated, the control logic may be implemented using any
one or a number of known programming and processing techniques or
strategies, and is not limited to the order or sequence illustrated
here for convenience only. For example, interrupt or event driven
processing is typically employed in real time control applications,
such as control of the vehicle engine or transmission. Likewise,
parallel processing, multitasking, or multithreaded systems and
methods may be used to accomplish the objectives, features, and
advantages of the present invention. The present invention is
independent of the particular programming language, operating
system, processor, or circuitry used to implement the control logic
illustrated.
[0032] With continuing reference to FIG. 2, engine coolant
temperature (ECT) is determined as represented by block 200. Engine
intercooler temperature (EIT) is determined as represented by block
202 while engine air temperature (EAT) is determined as represented
by block 206. ECT is compared to a corresponding engine coolant
temperature threshold as represented by block 206. If ECT is above
the engine coolant temperature threshold, control passes to block
208 where controller 46 determines whether EIT is below its
corresponding threshold. EAT is then tested in a similar manner as
represented by block 210. If any of the monitored fluid
temperatures represented by blocks 206, 208, and 210 is below its
corresponding threshold, control passes to an optional step
represented by block 212 which determines whether the engine is
idling. In one embodiment of the present invention, an option or
status bit is used to activate or deactivate the logic which
determines whether the cold engine output is activated only when
the engine is idling. That is, if the status bit is selected, a
cold engine output signal will be generated only if one of the
monitored fluid temperatures is below its corresponding threshold
and the engine is at idle. The idle condition may be determined
based on the active governor being the idle governor and/or based
on the position of the accelerator pedal. If the idle logic is
activated and the engine is idling, or if the idle logic is
deactivated, the cold engine output is asserted as represented by
block 214. Of course, if the idle logic is activated and the engine
is not idling, the cold engine output will not be asserted as
represented by block 216. The cold engine output may be used to
control one or more engine and/or vehicle accessories as
represented by blocks 218 and 220. The process repeats continuously
while the engine is running as the microprocessor continues to
execute the instructions and re-evaluate the engine operating
conditions.
[0033] With continuing reference to FIG. 2, when all of the
monitored fluid temperatures are above their corresponding
temperature thresholds (plus hysteresis where applicable) as
determined by blocks 206, 208, and 210, the cold engine output is
deactivated as represented by block 216. The cold engine output
signal is then used to control the associated engine and/or vehicle
accessories as represented by block 220. As described above, the
accessories controlled by the cold engine output signal may include
coolant heating systems, extra parasitic loads, shutters, exhaust
brakes, and the like.
[0034] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *