U.S. patent application number 10/708087 was filed with the patent office on 2005-08-11 for method and apparatus to control a low voltage fuel pump from a high voltage power source.
Invention is credited to French, Michael J., Koerner, Scott A..
Application Number | 20050176314 10/708087 |
Document ID | / |
Family ID | 34826352 |
Filed Date | 2005-08-11 |
United States Patent
Application |
20050176314 |
Kind Code |
A1 |
French, Michael J. ; et
al. |
August 11, 2005 |
METHOD AND APPARATUS TO CONTROL A LOW VOLTAGE FUEL PUMP FROM A HIGH
VOLTAGE POWER SOURCE
Abstract
An apparatus and method are presented to dynamically control
operation of an engine component, e.g. fuel pump assembly or oil
pump assembly, so that the engine component is operable at voltages
that exceeds its rated or maximum operational voltage. An engine
control monitors the rail voltage provided by an engine's energy
source and provides a dynamic control of the engine component to be
operable at that rail voltage. In this regard, the engine component
is controlled to be operable at voltages exceeding its rated or
maximum operational voltage, but is also controlled to be operable
at varying voltages that are above its rated maximum.
Inventors: |
French, Michael J.;
(Pleasant Prairie, WI) ; Koerner, Scott A.;
(Kenosha, WI) |
Correspondence
Address: |
BOMBARDIER RECREATIONAL PRODUCTS INC.
INTELLECTUAL PROPERTY DEPT
PO BOX 230
NORTON
VT
05907-0230
US
|
Family ID: |
34826352 |
Appl. No.: |
10/708087 |
Filed: |
February 6, 2004 |
Current U.S.
Class: |
440/88F |
Current CPC
Class: |
B63H 20/00 20130101;
B63H 20/002 20130101; F01M 2001/0215 20130101; F01M 2001/0253
20130101; F01M 1/02 20130101 |
Class at
Publication: |
440/088.00F |
International
Class: |
B63H 021/10 |
Claims
1.-18. (canceled)
19. An outboard motor comprising: an internal combustion engine
configured to provide thrust to propel a watercraft and having an
alternator configured to produce an operating rail voltage within a
rail voltage range when the internal combustion engine is running;
a fuel pump having a rated maximum voltage that is below the rail
voltage range, wherein the fuel pump is configured to supply fuel
to the internal combustion engine; and a control unit having a
control circuit to control the fuel pump to operate at a rail
voltage that exceeds the rated maximum voltage.
20. The outboard motor of claim 19 further comprising a DC energy
source connected to condition power from the alternator to provide
DC power to the fuel pump at a voltage within the rail voltage
range that exceeds the rated maximum voltage.
21. The outboard motor of claim 20 wherein the rail voltage range
is from 12 volts to 60 volts.
22. The outboard motor of claim 20 wherein the DC energy source
includes a switching regulator constructed to convert AC power
generated by the alternator to DC power and input the DC power to
the fuel pump at a voltage that exceeds 12 volts.
23. The outboard motor of claim 22 wherein the switching regulator
is further configured to provide DC power to the fuel pump at a
voltage of 30 volts.
24. The outboard motor of claim 19 wherein the control circuit is
further configured to control the fuel pump to be operable at
variable voltages.
25. The outboard motor of claim 19 further comprising a fuel pump
drive circuit connected to the fuel pump and configured to control
fuel pump operation based on input received from the control
unit.
26. The outboard motor of claim 26 wherein the control circuit is
further configured to pulse width modulate the fuel pump drive
circuit.
27. The outboard motor of claim 26 wherein the control circuit is
further configured to pulse width modulate the fuel pump drive
circuit to maintain pump operation at approximately 3 amperes.
28. The outboard motor of claim 26 wherein the control circuit is
further configured to pulse width modulate the fuel pump drive
circuit at 10 kHz.
29. The outboard motor of claim 19 wherein the internal combustion
engine is a two-cycle engine.
30. The outboard motor of claim 19 wherein the internal combustion
engine is a rope-start engine.
Description
BACKGROUND OF INVENTION
[0001] The present invention relates generally to internal
combustion engines and, more particularly, to a method and
apparatus to control operation of a fuel delivery system such that
the fuel delivery system is operable at an input voltage that
exceeds its rated operational voltage.
[0002] As a result of more stringent environmental concerns, desire
for improved fuel efficiency, reduced noise emission, consumer
desire for more robust operation, and the like, engine design and
operation has become increasingly more complex. Contributing to
this increased complexity is the incorporation of additional
mechanical and electronic components to control operation of the
engine and its components. The advent of additional electronic
components to control engine operation has greatly increased the
electrical load placed on the engine. This is particularly relevant
for engines of recreational products such as outboards,
motorcycles, ATVs, snowmobiles, PWCs, and lawn and garden
equipment.
[0003] Some modern engines, such as the EVINRUDE outboard motor,
have fuel injectors that are designed to operate at rather high
voltages that exceed that which can be provided by a 12 volt
battery and alternator. EVINRUDE is a registered trademark of the
present assignee. These injectors operate extremely fast and
responsive, and are not only state-of-the-art in terms of
performance, they are so highly tuned that engines so equipped
greatly exceed environmental emissions standards for years to come.
However, to obtain such exacting performance, the injectors operate
at a rather high voltage, preferably 55 volts.
[0004] To meet the electrical requirements of these and other
modern engines, larger batteries and/or alternators may be designed
to produce more current at a standard voltage level; however, such
alternators are large, heavy, and relatively expensive. It is also
possible, more practical, and more robust to provide a power source
capable of outputting higher voltages for power the engine and its
components. It can be problematic however in that most engine
components are not rated to operate at the increased voltages
output by the power source. As such, while some of the engine
components optimally run on at an increased voltage, other engine
components are not rated to operate at the increased voltage.
[0005] Simply, the total electrical load of the engine requires
more than 12 or 24 volts for optimal engine operation, but a number
of engine components are inoperable at voltages substantially
exceeding 12 or 24 volts. While these components could be
constructed to operate at the higher voltages, such components
would be very costly. Rather it is desirable to use standard
off-the-shelf components whenever possible. These components are
all traditionally 12 volts and some are rated to operate at 24
volts. A number of engine components are preferably 12 or 24 volt
rated and are able to withstand voltages nominally above 12 or 24
volts for short periods of time before overheating and failure. Two
such engine components include the fuel pump and oil pump of a
two-cycle internal combustion engine which are customarily designed
to operate with a nominal 12 or 24 volt input. As such, simple
incorporation of 12 or 24 volt rated components into an engine or
motor designed to operate a rail voltage substantially greater than
12 or 24 volts is problematic and not feasible. Moreover,
off-the-shelf engine components are typically rated to operate at a
nominal 12 or 24 volts. Since 12 or 24 volt rated engine components
have been widely accepted and widely available in the marketplace,
it would also be difficult to require a conversion to higher rated
voltage components.
[0006] It would therefore be desirable to design a system that
allows use of standard, off-the-shelf components to be operable
with an engine designed to operate at a rail voltage that
substantially exceeds the rated operational voltage of the standard
engine component. It would also be desirable to design the engine
component to be operable at variable voltages above its rated
operational voltage.
BRIEF DESCRIPTION OF INVENTION
[0007] The present invention relates to controls designed to allow
operation of an engine component at an input voltage that exceed
its rated or maximum operational voltage that overcome the
aforementioned drawbacks.
[0008] An engine control is presented that dynamically controls
operation of an engine component, e.g. fuel pump assembly or oil
pump assembly, so that the engine component is operable at voltages
that exceeds its rated or maximum operational voltage. The engine
control monitors the rail voltage provided by an engine's energy
source and dynamically controls the engine component to be operable
at that rail voltage. In this regard, the engine component is
controlled to be operated at voltages exceeding its rated or
maximum operational voltage, but is also controlled to be operable
at varying voltages above its rated maximum. As such, the engine
component is controlled to be functional despite fluctuations in
the engine's rail voltage. Accordingly, the engine component is
controlled to operate independent of its input voltage.
[0009] Therefore, in accordance with one aspect of the present
invention, a fuel delivery system is disclosed as having a fuel
pump configured to deliver fuel to an engine and rated to operate
in an operational voltage range. The fuel delivery system also
includes a fuel pump controller connected to the fuel pump and
configured to control operation of the fuel pump to operate with a
voltage input outside the operational voltage range of the fuel
pump.
[0010] In accordance with another aspect, the present invention
includes a control unit having a fuel pump drive circuit connected
to a fuel pump rated to operate in a first range of voltages. The
control unit also includes a voltage sensing circuit connected to a
voltage rail. The voltage rail has a rail voltage outside the first
range of voltages. A processor is connected to the voltage sensing
circuit and the fuel pump drive circuit to control operation of the
fuel pump to operate at the voltage rail.
[0011] According to another aspect of the present invention, an
outboard motor is provided and includes an internal combustion
engine configured to provide thrust to propel a watercraft and an
alternator configured to produce an operating rail voltage within a
rail voltage range when the internal combustion engine is running.
The motor also includes a fuel pump having a rated maximum voltage
that is below the rail voltage range and is configured to supply
fuel to the internal combustion engine. A control unit is provided
and includes a control circuit to control the fuel pump to operate
at a rail voltage that exceeds the rated maximum voltage.
[0012] Various other features, objects and advantages of the
present invention will be made apparent from the following detailed
description and the drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The drawings illustrate the best mode presently contemplated
for carrying out the invention.
[0014] In the drawings:
[0015] FIG. 1 is a perspective view of an exemplary outboard motor
incorporating the present invention.
[0016] FIG. 2 is a block diagram of an electrical system for an
electronically controlled engine according to one aspect of the
present invention.
[0017] FIG. 3 is a schematic of a fuel pump control circuit in
accordance with one aspect of the present invention.
[0018] FIG. 4 is a schematic of an oil pump control circuit in
accordance with another aspect of the present invention.
DETAILED DESCRIPTION
[0019] The present invention relates generally to internal
combustion engines, and preferably, to those whose operations are
controlled by an engine management module (EMM), or more generally,
by a control unit or ECU. FIG. 1 shows an outboard motor 10 having
an engine 12 controlled by a control unit 14 mounted directly to
the engine under engine cover 16. Engine 12 is housed generally in
a powerhead 18 and is supported on a mid-section 20 configured for
mounting on a transom 22 of a boat 24 or other water-going vessel
in a known conventional manner. Engine 12 is coupled to transmit
power to a propeller 26 to develop thrust and propel boat or other
watercraft 24 in a desired direction. The motor 10 includes a lower
unit 30 having a gear case 32 that includes a bullet or torpedo
section 34 formed therein and housing a propeller shaft 36 that
extends rearwardly therefrom. Propeller 26 is driven by propeller
shaft 36 and includes a number of fins 38 extending outwardly from
a central hub 40 through which exhaust gas from engine 12 is
discharged via mid-section 20. A skeg 42 depends vertically
downwardly from torpedo section 34 to protect propeller fins 38 and
encourage the efficient flow of outboard motor 10 through water.
One skilled in the art will appreciate that engine 12 may be either
a two-cycle or a four-cycle internal combustion engine; however, in
a preferred embodiment, engine 12 is a two-cycle engine that may be
used in various modalities that include an outboard motor,
snowmobile, ATV, PWC, motorcycles, scooters, or various lawn and
garden applications and equipment. Additionally, the engine may be
electronically started or rope started.
[0020] Moreover, while many believe that two-stroke engines are
generally not environmentally friendly engines, such preconceptions
are misguided in light of contemporary two-stroke engines. Modern
direct injected two-stroke engines and, in particular, EVINRUDE
outboard motors, are compliant with not only today's emission
standards, but emissions standards well into the future. However,
since these engines are so advanced, they require trained
technicians perform certain repairs and adjustments. As such, a
significant portion of the ability to manipulate the operation of
these motors has been restricted to qualified personnel in an
effort to ensure the future emission efficiency of the engines.
Further, the illustrated outboard motor has fuel injectors that are
extremely fast and responsive. These injectors are not only
state-of-the-art in terms of performance, they are so highly tuned
that engines so equipped greatly exceed environmental emissions
standards for years to come. To obtain such exacting performance,
the injectors operate at a rather high voltage, preferably 55
volts.
[0021] Referring now to FIG. 2, the electrical and electronics
system 48 of motor 10 is schematically shown. The electrical system
includes an energy source assembly 50 that includes a permanent
magnet alternator 52 and a computer controlled switching regulator
54 to provide electrical power to the motor's electronics. In
accordance with well-known alternator operation, the alternator 52
produces alternating current (AC) 55 by converting the engine's
mechanical energy into alternating electrical current during engine
operation. In this regard, a portion of the mechanical energy
generated by the engine crankshaft during engine operation is
translated to the alternator 52 for generation of AC. One skilled
in the art will readily appreciate that alternators typically
comprise a stator (not shown) and a flywheel (not shown) having
magnets (not shown) that is driven, directly or indirectly, by the
engine's crankshaft. Engine electronics generally operate with
direct current (DC), therefore, an AC to DC converter is
customarily used to condition the AC signal generated by the
alternator to provide a DC signal usable by the engine electronics.
In a preferred embodiment however, a computer controlled switching
regulator 54 converts the AC output of the alternator 52 into DC.
In this regard, the regulator 54 is controlled by a dedicated
control unit 56 or is controlled by the ECU.
[0022] The regulator 54 is controlled to provide a DC signal at a
desired rail voltage, generally referenced 58, that is used to
provide power to the various electronics of the motor. In one
embodiment, the regulator is dynamically controlled to provide a
rail voltage ranging from 12 to 60 volts and, preferably, to
provide a 55 volt rail voltage for powering the motor's
electronics. While it is customary to provide a 12 volt rail
voltage, engine operation is optimized with a rail voltage greater
than 12 volts. However, as will be described, some of the motor's
electronics may not be rated to operate at a voltage greater than
12 volts. As such, the present invention includes a control system
for controlling operation of a seemingly-incapable component, e.g.
a fuel or oil pump, to be operational and functional with a rail
voltage that exceeds the component's rated or maximum operational
voltage. It is also contemplated that a voltage sensing circuit 60
may be incorporated to provide voltage feedback 62 to a control
unit 56 so that the control unit may regulate engine and motor
operation dynamically based on the rail voltage output by the
switching regulator 54. As will be described however, an engine
component may have a dedicated drive circuit that controls
operation of an engine component based on the rail voltage of the
electrical system independent, or in conjunction, with the control
unit. In this regard, as shown in FIG. 2, a fuel pump 64, an oil
pump 66, and an auxiliary component 68 are individually driven by a
drive circuit 70, 72, and 74, respectively. For purposes of
illustration, the control system will be described with respect to
dynamic control of fuel pump 64 and oil pump 66. It is understood,
however, that the control system may be used to control operation
of other or auxiliary electronic motor components 68.
[0023] Control of the fuel pump to be operational on a rail voltage
exceeding its rated or maximum operation voltage will be described
in particular to FIG. 3. The fuel pump drive circuit 70 includes
operational circuitry to dynamically control operation of the fuel
pump to be operational with an applied voltage that exceeds is
rated or maximum voltage. More particularly, the drive circuit
includes a microcontroller 61 that receives rail voltage feedback
63 from the rail or applied to the fuel pump 64. The
microcontroller 61, from the voltage feedback 63 received,
selectively switches the fuel pump, schematically illustrated as an
inductor L1, between ON and OFF states via switch S1 to control
power dissipation in the fuel pump. In a preferred embodiment, S1
is a MOSFET, but is contemplated that other switching components
may be used. Controlling power dissipation in the fuel pump is
necessary to prevent overheating and fuel pump failure.
[0024] The fuel pump is designed to draw fuel from a fuel source
(not shown) and deliver pressurized fuel to a carburetor (not
shown) or fuel injectors (not shown), and is rated to operate at 3
amperes DC with a nominal 12 volt input. As such, an input voltage
greater than a nominal 12 volts, absent conditioning, may be
damaging to and result in failure of the fuel pump. Therefore, the
drive circuit 70 is controlled to prevent excessive power
dissipation in the fuel pump by switching the fuel pump between ON
and OFF states as a function of the rail voltage 58. That is, in
accordance with pulse width modulation, the microcontroller 61
selectively switches S1 and, as a result the fuel pump between ON
and OFF states, based on a duty cycle that is determined from a
ratio of the rated or maximum voltage of the fuel pump and the rail
voltage. For example, if the rail voltage is 60 volts and the pump
is rated to operate at 12 volts, an exemplary duty cycle could be
equal to 12/60 or 20%, not factoring for losses. Accordingly, the
microcontroller will switch the fuel pump between ON and OFF states
consistent with a 20% duty cycle and prevent excessive power
dissipation. In this regard, the greater the measured voltage above
the rated voltage, the shorter the pulses of the pulse width
modulation.
[0025] Basing the duty cycle of switching on the rated or maximum
operating voltage of the fuel pump and the rail voltage 58 output
by the regulator 54 allows the fuel pump to be controlled to be
fully operational and functional with varying voltages. Simply, the
duty cycle changes as the value of the rail voltage changes. As
such, changes in the rail voltage are accommodated for in fuel pump
operation and power dissipation management. In a preferred
embodiment, the duty cycle is dynamically adjusted to maintain fuel
pump operation at 3 amperes. It is contemplated that the duty cycle
may be adjusted to maintain fuel pump operation at other amperages
or range of amperages.
[0026] Using a ratio of rated voltage and rail voltage to determine
duty cycle, the microcontroller 61 inputs a pulse width modulated
(PWM) signal to switch S1 to control operation of the fuel pump 64.
While it is contemplated that a DC to DC converter could be used to
lower the rail voltage to a level equivalent to the pump's rated
voltage, it is preferred to regulate power dissipation through PWM.
With a DC to DC converter the delay in energizing the fuel pump at
engine start-up may cause a delay in pressurizing the fuel system
that may be too long for efficient engine operation. Through the
PWM technique heretofore described, the fuel pump is energized
during engine start-up to pressurize the fuel system. Further,
while manufactures of certain 12V/24V pumps/motors state that
operating their pumps at higher voltages may negatively affect the
operational lifetime of the fuel pump and, in particular, reduce
the brush life of the motors, using the novel control of the
present invention has shown through testing that such pump life
exceeds that of most recreational products in which the pumps are
implemented. Additionally, by powering the fuel pump with the rail
voltage provided by the switching regulator, the fuel pump does not
need to be connected to a battery which supports incorporation of
the present invention in a battery-less application. Further, it is
contemplated that the engine control unit 56 may provide feedback
or other data across data line 73 to microcontroller 61 to enhance
the dynamic control of fuel pump 64.
[0027] As mentioned previously, a fuel pump illustrates one example
of an engine component that can be controlled to operate with an
input voltage that exceeds its rated or maximum operable voltage.
Another component for which the present invention may be
implemented to control is an oil pump. The oil pump 66 is
controlled by an oil pump drive circuit 72. Oil pump 66 is designed
to force oil, under pressure, to various parts of the engine. In a
preferred embodiment, the oil pump is rated to operate at 1 ampere
DC on a 24 volt input. Similar to the fuel pump described above,
prolonged exposure to an input voltage greater than 24 volts will
cause the oil pump to overheat and eventually fail. Accordingly,
the present invention includes a control system designed to control
operation of the oil pump assembly on a greater than 24 volt input,
but prevent overheating as well.
[0028] Control of the oil pump to be operational on a rail voltage
exceeding its rated or maximum operation voltage will be described
in particular to FIG. 4. FIG. 4 is schematic representation of a
control circuit to regulate operation of the oil pump. The oil
pump, which is schematically illustrated as an inductor L2, is
shown connected to a 55 volt input. The oil pump is switched
between an ON state and an OFF state by a power switch S2 that in a
preferred embodiment is a MOSFET. The MOSFET is biased by the
output of a comparator COMP1 that compares a voltage measured
across a sense resistor R to a voltage reference V.sub.ref.
Specifically, the voltage through the MOSFET is compared to the
voltage drop experienced across the sense resistor by a comparator
COMP2. The voltage across the MOSFET and the voltage drop across
the sense resistor is input to COMP2 which generates a single
output indicative of scaled voltage across the MOSFET. This scaled
voltage is input to COMP1 and compared thereat to the reference
voltage. Accordingly, if the difference between the scaled voltage
and the reference voltage is within a pre-defined threshold, the
comparator will provide an output at a voltage that overcomes the
bias of the MOSFET and thereby cause (or maintain) running of the
oil pump in an ON state. Conventionally, MOSFETS are constructed
with a bias voltage or threshold of 5 volts, therefore, an output
of the comparator COMP1 greater than 5V will bias the MOSFET in an
ON state. Conversely, an output less than 5V will be insufficient
to overcome the bias and, as a result, the MOSFET will switch to an
OFF state. As such, the oil pump will be switched OFF as well. In
this regard, through high frequency switching of the MOSFET between
ON and OFF states, current through the oil pump may be maintained
relatively at its rated amperage.
[0029] In a preferred embodiment the oil pump is designed to run at
1 ampere. Therefore, the value of the sense resistor and the
operating parameters of the comparator are selected to maintain
operation of the oil pump at approximately 1 ampere. It is
contemplated however that the present invention is applicable with
an oil pump designed to operate at other amperages. Further, it is
contemplated that the engine control unit 56 may provide feedback
or other data to microcontroller 61 via control line 75 to enhance
the dynamic control of oil pump 66.
[0030] Additionally and referring again to FIG. 2, it is
contemplated that control techniques heretofore described may be
used to control operation of other auxiliary components 68 of the
motor. In this regard, operation of an auxiliary component 68 may
be regulated by an auxiliary drive circuit 74, independent or
dependent of control unit 56 via control line 77, to allow
operation of the auxiliary component on a rail voltage that exceeds
its rated or maximum operational voltage. The auxiliary drive
circuit 74 may operate similar to the fuel pump drive circuit 70 to
control power dissipation through voltage dependent pulse width
modulation of a corresponding auxiliary component or regulate an
auxiliary component in a manner similar to that described with
respect to the oil pump drive circuit 72.
[0031] Furthermore, while the present invention has been described
with respect to independent drive circuits for controlling the
engine components, it is contemplated and appreciated that the
engine control unit may control operation of the engine component
to operate with a voltage that exceeds its rated voltage.
[0032] Therefore, in accordance with one embodiment of the present
invention, a fuel delivery system is disclosed as having a fuel
pump configured to deliver fuel to an engine and rated to operate
in an operational voltage range. The fuel delivery system also
includes a fuel pump controller connected to the fuel pump and
configured to control operation of the fuel pump to operate with a
voltage input outside the operational voltage range of the fuel
pump.
[0033] In accordance with another embodiment, the present invention
includes a control unit having a fuel pump drive circuit connected
to a fuel pump rated to operate in a first range of voltages. The
control unit also includes a voltage sensing circuit connected to a
voltage rail. The voltage rail has a rail voltage outside the first
range of voltages. A processor is connected to the voltage sensing
circuit and the fuel pump drive circuit to control operation of the
fuel pump to operate at the voltage rail.
[0034] According to another embodiment of the present invention, an
outboard motor is provided and includes an internal combustion
engine configured to provide thrust to propel a watercraft and an
alternator configured to produce an operating rail voltage within a
rail voltage range when the internal combustion engine is running.
The motor also includes a fuel pump having a rated maximum voltage
that is below the rail voltage range and is configured to supply
fuel to the internal combustion engine. A control unit is provided
and includes a control circuit to control the fuel pump to operate
at a rail voltage that exceeds the rated maximum voltage.
[0035] The present invention has been described in terms of the
preferred embodiment, and it is recognized that equivalents,
alternatives, and modifications, aside from those expressly stated,
are possible and within the scope of the appending claims. While
the present invention is shown as being incorporated into an
outboard motor, the present invention is equally applicable with
other recreational products, some of which include inboard motors,
snowmobiles, personal watercrafts, all-terrain vehicles (ATVs),
motorcycles, mopeds, power scooters, and the like. Therefore, it is
understood that within the context of this application, the term
"recreational product" is intended to define products incorporating
an internal combustion engine that are not considered a part of the
automotive industry. Within the context of this invention, the
automotive industry is not believed to be particularly relevant in
that the needs and wants of the consumer are radically different
between the recreational products industry and the automotive
industry. As is readily apparent, the recreational products
industry is one in which size, packaging, and weight are all at the
forefront of the design process, and while these factors may be
somewhat important in the automotive industry, it is quite clear
that these criteria take a back seat to many other factors, as
evidenced by the proliferation of larger vehicles such as sports
utility vehicles (SUV).
* * * * *