U.S. patent application number 12/880049 was filed with the patent office on 2011-03-17 for fuel system.
Invention is credited to Nagesh Mavinahally, Jay Veerathappa.
Application Number | 20110061637 12/880049 |
Document ID | / |
Family ID | 43729247 |
Filed Date | 2011-03-17 |
United States Patent
Application |
20110061637 |
Kind Code |
A1 |
Mavinahally; Nagesh ; et
al. |
March 17, 2011 |
Fuel System
Abstract
In various embodiments, a metering apparatus may be associated
with an engine. The metering apparatus may include a first
passageway for transporting air to a first port of an engine, and a
second passageway for transporting gaseous fuel to a second port of
the engine.
Inventors: |
Mavinahally; Nagesh;
(Northridge, CA) ; Veerathappa; Jay; (Northridge,
CA) |
Family ID: |
43729247 |
Appl. No.: |
12/880049 |
Filed: |
September 10, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61276584 |
Sep 14, 2009 |
|
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Current U.S.
Class: |
123/65R ;
123/472 |
Current CPC
Class: |
F02M 21/0239 20130101;
F02D 19/024 20130101; F02B 25/22 20130101; F02B 25/14 20130101;
Y02T 10/30 20130101; F02M 21/0212 20130101; Y02T 10/32 20130101;
F02B 2075/025 20130101 |
Class at
Publication: |
123/65.R ;
123/472 |
International
Class: |
F02B 25/00 20060101
F02B025/00; F02M 51/00 20060101 F02M051/00 |
Claims
1. A metering apparatus (9400 in FIGS. 5, 6, and 7) comprising: a.
a first passageway (9480) for transporting air to a first port (98)
of an engine; b. a second passageway (9180) for transporting
gaseous fuel to a second port (84) of the engine; c. at least one
pressure chamber; d. at least one metering chamber; and e. a fuel
injector (9138) injecting gaseous fuel into second passageway
(9180).
2. The metering apparatus (9400) of claim 1 in which the metering
apparatus is a carburetor.
3. The metering apparatus (9400) of claim 1 in which the metering
apparatus is an electronic fuel injection system.
4. The metering apparatus (9400) of claim 3 in which the metering
apparatus comprises: a) at least one pressure regulator (9103);
5. The metering apparatus of claim 3 further comprising an
electronic control unit, in which the electronic control unit is
operable to: a) monitor a first state of an engine; b) set a second
state of the first control valve based on the first state; and c)
set a third state of the second control valve based on the first
state.
6. The metering apparatus (9400) of claim 1 in which the gaseous
fuel is one of: (a) liquefied petroleum gas; (b) propane; (c)
gaseous fuel consisting of methane gas; (d) hydrogen; (e) landfill
gas; and (f) natural gas.
7. The metering apparatus of claim 1 further comprising: a) a first
control valve (9432) for controlling flow of air into the first
passageway; and b) a second control valve (9162) for controlling
flow of an air-fuel mixture into the second passageway.
8. The metering apparatus of claim 7 in which each of the first and
second control valves are one of: (a) butterfly valves; (b) sliding
valves; and (c) rotary valves.
9. The metering apparatus of claim 7 in which each of the first and
second control valves are a combination of: (a) butterfly valves;
(b) sliding valves; and (c) rotary valves.
10. The metering apparatus of claim 7 in which the first control
valve and the second control valve are on a shaft (9584).
11. The metering apparatus of claim 7 in which the first control
valve is on a first shaft and the second control valve is on a
second shaft, in which the first shaft is different than the second
shaft.
12. The metering apparatus of claim 11 in which each of the first
and second control valves opens and closes periodically at
substantially the same frequency, but in which the first control
valve lags the second control valve.
13. The metering apparatus of claim 7 in which the first control
valve and the second control valve are in a single body.
14. The metering apparatus of claim 7 in which the first control
valve is on a first body and the second control valve is on a
second body.
15. The metering apparatus of claim 3 further comprising an
electronic control unit, in which the electronic control unit is
operable to: a) monitor a first state of an engine; b) set a second
state of the first control valve based on the first state; and c)
set a third state of the second control valve based on the first
state.
16. The metering apparatus of claim 15, in which, in monitoring the
first state of the engine, the metering apparatus is operable to
monitor one or more of: (a) engine speed; (b) temperature; (c)
throttle position; (d) fuel pressure; (e) engine temperature; (f)
ambient temperature; and (g) spark timing.
17. The metering apparatus of claim 15, in which the electronic
control unit is further operable to monitor a position of a
throttle (9400) of the metering apparatus, and in which the
electronic control unit is operable to set the second and third
states based on a throttle position.
18. The metering apparatus of claim 1 in which the first passageway
and the second passageway are passageways through an integrally
cast body.
19. A metering apparatus comprising a single body, the single body
including: a) a first passageway (9480) for the transport of air;
b) a second passageway (9180) for the transport of an air-fuel
mixture; c) at least one pressure regulator; and d) a metering
chamber, in which the fuel is not pre-mixed with oil; and the fuel
is a gaseous fuel.
20. A metering apparatus comprising: a) a first passageway (9480)
for the transport of air; b) a second passageway (9180) for the
transport of an air-fuel mixture; and c) an oil injector (101) for
injecting oil in the second passageway.
21. An apparatus comprising: a) a two-stroke engine with a first
port for admitting air and a second port for admitting fuel; b) a
metering apparatus, the metering apparatus operable to generate a
gaseous fuel mixture; c) a first passageway for transporting air
from the metering device to the first port; d) a second passageway
for transporting the gaseous fuel mixture from the metering device
to the second port; and e) an oil injector (101) for injecting oil
in the first passageway.
22. A metering apparatus comprising: a) a throttle body (9102) b) a
first passageway for admitting air; c) a second passageway for
admitting gaseous fuel; d) an electronic control unit (9136)
mounted on the throttle body (9102); and e) a gaseous fuel injector
9138 in the throttle body (9102).
23. The metering apparatus of claim 22 in which the apparatus does
not have a metering chamber and does not have a pressure chamber.
Description
RELATED APPLICATIONS
[0001] The present application claims the benefit of priority of
U.S. Provisional Patent application No. 61276584, filed Sep. 14,
2009, and entitled "PISTON AND CYLINDER FOR STRATIFIED TWO-STROKE
ENGINES", the entirety of which is incorporated by reference herein
for all purposes.
FIELD
[0002] Various embodiments relate to two stroke internal combustion
engines. Various embodiments relate to two stroke internal engines
with stratified scavenging.
[0003] Various embodiments may find application in two-stroke
internal combustion engines. Some applications include a small high
speed two stroke engine, such as utilized in hand-held power
equipment such as leaf blowers, string trimmers, and hedge
trimmers. Some applications include wheeled vehicle applications
such as mopeds, motorcycles, scooters, and small outboard boat
engines. The small two stroke engine has many desirable
characteristics, including simplicity of construction, low cost of
manufacturing, high power-to-weight ratios, high speed operational
capability and, in many parts of the world, ease of
maintenance.
BACKGROUND
[0004] Inherent drawbacks of two stroke engines are high emission
levels and poor fuel economy due to short-circuit loss of fuel and
air charge during the scavenging process. One drawback of the
simple two-stroke engine is a loss of a portion of the fresh
unburned fuel charge from the cylinder during the scavenging
process. In the two-stroke engine, the homogeneous charge enters
the cylinder through transfer ports during the scavenging process,
when the exhaust port is also open. As such, some of the charge
escapes through the exhaust port leading to high levels of
hydrocarbons (HC) in the tailpipe. This leads to the poor fuel
economy and high emission of unburned hydrocarbon, thus, rendering
the simple two stroke engine difficult to comply with increasingly
stringent governmental pollution restrictions. This drawback can be
relieved by separating the scavenging of the cylinder, with fresh
air, from the charging of the cylinder, with fuel. This separation
can be achieved by having a buffer medium of air between the fresh
charge and the burnt gas, during the scavenging process.
[0005] Several concepts and technologies have been proposed or
tried to circumvent the short-circuit loss of fresh charge. Among
these techniques are direct or indirect fuel injections, stratified
scavenging, air-head, air assisted fuel injection, and compressed
wave injection. Most of these technologies are either complex,
expensive or need more parts. The fuel injection technology is not
economical for small engines but air-head scavenging and stratified
scavenging are promising.
[0006] Air-head scavenging systems disclosed in U.S. Pat. Nos.
4,821,787, 6,112,708, and 6,367,432 describe reed valve controlled
air passages in air-head scavenged two-stroke engines. The use of
reed valves increases the cost.
[0007] U.S. Pat. Nos. 7,363,888, 6,973,899, 7,025,021, 6,895,910,
6,289,856, and 6,497,204 describe piston controlled air head
scavenging. However, the location of the ports with respect to the
crankshaft do not meet the configuration necessary to have the
exhaust port in line with the crankshaft as packaged by, for
example, Echo brand chainsaw. Secondly the inlet of air requires
dual ports to supply air to transfer passages on either side of the
exhaust port.
[0008] U.S. Pat. No. 7,331,315, and Application 2006243230,
describe a fuel injected stratified engine. However, there are
several drawbacks of those fuel injection systems. First, one
hundred percent of the air goes through the transfer passages
during the induction process and the same transfer passages are
then used to transfer the charge from the crankcase to the
combustion chamber during the gas exchange process. Secondly, the
transfer passage ports are likely to be very large and the fuel may
stick to walls in transfer passages, at least during cold start,
and some of it may be lost into exhaust, which increases HC
emission.
[0009] It is desirable to have a simple two-stroke engine with
fewer parts and that is easy to manufacture and assemble. It is
also desirable to have a piston that can be die cast for low cost
manufacturability.
[0010] In most engines, fuel is mixed with air using a simple
carburetor. However, among the disadvantages of the carburetor
systems are that they need a manual choke and do not compensate for
variation in ambient and operating temperatures. Thus the fuel
consumption is higher and hence brake specific emission is also
higher. Also, the conventional carburetors in small engines have
built in fuel pumps that depend on the pulsation of crankcase
pressure. There are more advanced electronic fuel systems commonly
used in automobiles and some small engines. For example U.S. Pat.
Nos. 7,331,315, and 7,536,983, and PCT US2007/074982 describe
electronic fuel injection systems for small two-stroke engines,
which have fuel pumps that depend on engine pulses for pumping the
fuel at a certain pressure, but can become unreliable as they
entirely depend on crankcase pulses. For instance, the crankcase
pulses could be affected by the blow down of burnt gases into the
crankcase chamber and as such pulse pump could be unreliable. Some
engines use electrical or mechanical pumps for delivering fuel at a
higher pressure to the injector. Secondly they use gasoline as
fuel. In U.S. Pat. No. 6,609,509 the fuel used is LPG (liquefied
petroleum gas), however, the system is more of a carburetor type
than electronically controlled injection system.
SUMMARY
[0011] An engine according to various embodiments includes a
cylinder with at least one transfer passage that is a channel in
the cylinder bore. The top end of the channel opens into the
combustion chamber and the lower end opens into the crankcase
chamber. The top end is opened and closed by the piston. As the
piston is moving upward, the passage in the piston skirt opens the
transfer port into the crankcase. The passage may be just a window
in the piston or a special passage. Connection of transfer passage
to air and crankcase is alternative and is accomplished by the cut
out in the piston which also synchronizes with the air inlet port
in the cylinder. The main charge inlet into the crankcase takes
place in a usual manner either through the piston-controlled inlet,
rotary valve, or a reed valve system. Only a piston controlled
inlet is shown, as an example, in the illustrations, which
illustrate exemplary embodiments. The piston may also have a cut
out 84b, shown in FIG. 4, on the skirt to time the intake of
charge. The cut out on the piston skirt for the charge is
determined by the location of charge inlet port 84. If the charge
inlet port is at a lower height than the air inlet port 98, then
there is no need for the cut out.
[0012] In a quadruplet type transfer passage, the top end of the
said passage is connected to the adjacent transfer passage either
through a cut out in the piston or directly through a passage at
the top between the pair of transfer passages. The quadruplet
passage increases the total volume of air, which acts as a buffer
medium in the transfer passages. It also helps clear the fresh
charge in the transfer passages from the previous cycle. The amount
of air getting into each of the passages may be distributed and
controlled by the deflectors on the piston window.
[0013] The total length of the transfer passage may be increased by
having the transfer passage continue into the crankcase as a groove
on the crankcase wall.
[0014] In various embodiments, the air channel in the piston and
the air and charge inlets are mostly in one quadrant. And the
quadrant lies between the intake side and the flywheel side.
However, the inlet ports 84, and 98 can be in any one of the
quadrants as the case may be.
[0015] An engine according to various embodiments allows for easier
casting of the piston than would be possible with other
systems.
[0016] An engine according to various embodiments includes an
intake port and an exhaust port that are both in line with the
crankshaft. Various embodiments include an engine with an exhaust
port and muffler. Having an exhaust port and exhaust muffler may
advantageously reduce the width of the engine. For example, the
exhaust muffler and discharge can be in the front toward the chain
in a chainsaw application. For example, the exhaust muffler and
discharge can be in the back of a trimmer engine, while the intake
system (such as carburetor or throttle body with fuel injection)
can be on the side for easy access by the user.
[0017] In various embodiments, having an exhaust port (50) in line
with the piston pin (200) may provide for easy assembling of the
piston pin (200) in a mono-block casting.
[0018] In an alternate fuel mixing system, the conventional
carburetor 34 may be replaced by a dual (or a single) intake
electronic LPG fuel (9101) injection throttle body 9400, where the
charge inlet passage and air intake passages (312, 313) are
respectively connected to the primary intake passage (9180) and
secondary intake passage (9480) in the throttle body (9102) to
connect to the crankcase chamber (26) through the intake port (84)
in the cylinder block (12) and the air inlet port (98). The EFI
throttle body (9400) having first and second valves (9432, 9162)
may be incorporated to regulate mass flow into the air intake and
charge intake passages (313, 312) respectively. The EFI throttle
body (9400) may have an electronically controlled LPG fuel injector
(9138), either in the throttle body 9102 or in the charge intake
passage (312). The pressurized LPG fuel (9101) is supplied from an
external pressure regulator (2917) that may be integral to the
cylinder block (12). The LPG fuel (9101) is contained in a fuel
tank (2007). The timing and amount of fuel (9101) injection is
controlled by an ECU (9136), based on the received input signals,
such as crank angle position from a crank angle position sensor
(9412) through a wire harness 9114, the speed is measured through
the same sensor or from the ignition pulses received by the
ignition module (9404), intake temperature as measured by the
sensor (9146), possibly cylinder block (12) temperature, and
throttle position from the sensor 9142.
[0019] The advantages of LPG fuel injection as envisioned in
various embodiments is that the fuel is already in gaseous form,
and therefore the fuel does not condense on the walls of the
transfer passages, secondly the fuel is already under pressure,
therefore the fuel injection system described herein does not need
a separate pump.
[0020] In various embodiments, a reed valve type air head engine
can be used in conjunction with the oil injection into the charge
passage to minimize the exhaust emission. In various embodiments,
the fuel system can be either a dual passage carburetor or a dual
passage fuel injection system. Such embodiments may be used in a
gaseous fueled two-stroke engine. One advantage with reed valve
type air head engine is that the simpler and conventional piston
without cavity or air channel can be used, where in the air is
admitted into the transfer passages through the reed valves as
described in U.S. Pat. No. 6,112,708.
[0021] It will be appreciated that various embodiments described
herein may be applicable to two stroke engines, to four stroke
engines, and/or to any other type of engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The foregoing aspects and other features are explained in
the following description, taken in connection with the
accompanying drawings where:
[0023] FIG. 1 is a horizontal sectional view illustration of an
exemplary embodiment of a two-stroke engine with an air channel in
the piston.
[0024] FIG. 2 is a longitudinal sectional view illustration of an
exemplary embodiment of a two-stroke engine shown in FIG. 1.
[0025] FIG. 3 is a front view of an exemplary embodiment of a
two-stroke engine showing locations of the air and charge
inlets.
[0026] FIG. 4 is a view illustration of the piston showing air
channel and the window, according to some embodiments.
[0027] FIG. 5 is a longitudinal sectional view illustration of an
exemplary embodiment of a two-stroke engine shown in FIG. 1 having
an electronic LPG fuel injected throttle body.
[0028] FIG. 6 is a cross sectional front view of an embodiment of
an electronic LPG fuel injected throttle body with dual intake
butterfly valves, fuel metering chamber, and fuel pressure
regulator.
[0029] FIG. 7 is side view of FIG. 6.
[0030] FIG. 8 is a view illustration of the engine embodiment shown
in FIG. 1 showing the quadrants of the engine.
[0031] FIG. 9 is a view illustration of an engine according to some
embodiments.
DETAILED DESCRIPTION
[0032] Various embodiments include a stratified charge two-stroke
engine (10) including a cylinder block (12), charge inlet port (84)
substantially in line with the crankshaft (22), air inlet port (98)
almost parallel to the crankshaft (22) (in which the projection of
the inlet port 98 is somewhat perpendicular to the axis of the
crankshaft), piston (16) having an air channel (96) substantially
perpendicular to the piston pin (200) and having piston windows
(100a and 100B) almost in line with the piston pin (200) having
deflector (1023) to divide the incoming air to two sides of the
piston (16), air inlet passage (313) and charge inlet passage (312)
being substantially perpendicular to the crankshaft (22). In some
embodiments, the stratified charged two stroke engine has an
electronic LPG fuel injection system (9400). In some embodiments,
an LPG Electronic Fuel Injection System (9400) has a throttle body
(9102), receives LPG fuel (9101) through an inlet (9110), has an
integrally cast pressure chamber (9105) and fuel metering chamber
(9116) through an internal fuel passage (9126) connected to an
electronically controlled LPG injector (9138) (or an orifice as in
a carburetor, where flow of fuel is regulated by the valve, as in a
carburetor). Throttle body (9102) may have two butterfly throttle
valves (which could also be of rotary or slide valves) (9162 and
9432) operating a throttle position sensor (9142) on an ECU
(9136).
[0033] Illustrated in FIGS. 1-4 is an exemplary two stroke engine
10 having a cylinder block 12 that houses a cylinder bore 14. A
piston 16 reciprocates within the cylinder bore 14 and is connected
by means of a connecting rod 18 to a crank pin 20 on a circular
crank web 21 of a crankshaft 22. The crankshaft 22 is journaled for
rotation about a crankshaft axis 19 within a crankcase chamber 26
of a crankcase 28 that is affixed to the lower end of the cylinder
block 12 in a suitable manner (the cylinder block 12 and the
crankcase 28 may also be of mono-block type). A combustion chamber
30 is defined as a region within the cylinder bore 14 above the
piston 16. The engine includes a two-way scavenging system
including transfer passages 11 between the crankcase chamber 26 and
the combustion chamber 30. The transfer passages 11 are used for
scavenging and allowing a fresh fuel/air charge to be drawn from
the crankcase chamber 26 into the combustion chamber 30 through a
transfer port 33 in the cylinder block 12 at the completion of a
power stroke.
[0034] A rich fuel/air mixture is inducted into the combustion
chamber 30 of the cylinder bore 14 by a charge induction system 32
which includes a carburetor 34, charge inlet passage 312, charge
inlet port 84. The charge inlet port 84 is opened and closed by the
piston 16, which has inlet window 84 cut out on the piston skirt.
In some embodiments, it is possible not to have the cut out as in
the case of a conventional engine. The fresh air inlet system
consists of the induction system including the carburetor 34 having
air control valve 94, air inlet passage 313, and air inlet port 98.
The air inlet port 98 is opened and closed by the piston 16 which
has the cut out 99, which has one window 100a on the intake side
and another window 100b on the opposite side. The window 100a
aligns with the transfer port 33a (and 33b) at the appropriate
time, as the piston moves upward after closing the exhaust port 50.
The window 100b aligns with the transfer ports 33a' (33b') in the
same manner and timing as the window 100 with the ports 33a (and
33b). The piston windows 100a and 100b are in gaseous communication
through the air channel 96 in the piston 16. The air channel 96 may
be of different cross sectional area than the area of the cut out
99. The air channel 96 is substantially perpendicular to the
crankshaft, but need not necessarily be perpendicular, in some
embodiments. The charge inlet port 84 is substantially in line with
the crankshaft, but need not necessary be so, in some embodiments.
As illustrated in FIG. 1, the air channel 96 and the charge inlet
through inlet port 84 appear to be at right angles to each other.
Also, the projection of the air inlet port 98 and charge inlet port
84 are substantially at right angles in some embodiments. However,
these need not necessarily be so, in some embodiments.
[0035] The windows 100a and 100b have deflectors 1010a and 1010b to
deflect the air into the transfer ports 33a and 33a'. There is also
one deflector 1023 at the edge of the cut out 99 to help deflect
the incoming air into the window 100a and may be designed to
provide restriction for the flow of air into air channel 96.
[0036] The air-head scavenged engines provide a buffer medium of
air between the fresh charge and the burned gas during the
scavenging process. When the transfer ports open, the air enters
the combustion chamber first and is most likely to be
short-circuited, in the sense that a small fraction of air is lost
into the exhaust. The air is inducted into the transfer passage
during the intake process, when the piston is ascending. In the
most common piston ported air-head engines, air and charge inlet
are perpendicular to the crankshaft, while the exhaust port is
perpendicular to the crankshaft and the transfer passages are on
either side of exhaust port and mostly toward the crankshaft.
However, in certain applications, such as the one used by Echo, the
exhaust port is in line with the crankshaft and the intake port is
from the flywheel side. This arrangement makes it difficult to
adopt conventional piston porting for air-head scavenging.
[0037] In the exemplary embodiment the piston porting is designed
to adapt air-head scavenging in a two-stroke engine where the
exhaust can be in line or at any angle to the crankshaft. Secondly
the inlet passages and ports for the air and charge can be almost
parallel to each other in the plane perpendicular to the cylinder
axis. But they can be at an angle too.
[0038] The two-stroke engine described in these embodiments
consists of air inlet port, opened and closed by the window on the
piston for gaseous communication between the air inlet port and the
transfer ports at the top of the transfer passages. The air channel
in the piston is for gaseous communication between piston window on
one side of the piston to the piston window on the opposite side of
the piston to supply air from air inlet to the transfer passages
farther away from the air inlet port.
[0039] The air inlet port is in gaseous communication with lower
end of the transfer passage at appropriate times only. The lower
end of the transfer passage opens in to the crankcase chamber. The
timing of the gaseous communication between the air inlet port and
the transfer passage is controlled by the window in the piston. The
air in the transfer passage acts as a buffer medium between the
charge and the burnt gas to minimize the loss of charge into
exhaust and thereby lowers the exhaust emission.
[0040] FIGS. 1 through 5 illustrate a quadruplet transfer passage
type two-stroke engine, according to some embodiments; wherein
there are four transfer passages (and ports) two on each side of
the exhaust port 50. As the piston 16 moves upward, the exhaust
port 50 is closed. Soon after the exhaust port is closed, the cut
out 99a aligns with the air inlet port 98 allowing the fresh air to
flow into the engine from the ambient through the air inlet passage
313 and into the transfer passages 11. The cut out 99 which is in
gaseous communication with the windows 100a and 100b allows the air
to flow into the transfer ports 33 as the two windows now align
with the transfer ports 33 as the piston moves upward. Thus the air
flows from the ambient into the transfer passages 11 during the
upward travel of the piston. Thus air in the transfer passage acts
as a buffer medium during scavenging to minimize the loss of fresh
charge. As the piston continues to move upward, the charge inlet
port 84 is now opened by the piston skirt which may have a cut out
84b. Thus only an air-fuel mixture, called the charge, enters the
crankcase chamber 26 directly. As the piston continues to move
upward, it compresses the charge in the combustion chamber 30 for
explosion and expansion of the burnt gases during the power stroke.
The exhaust of burned gases occur as the piston moves downward and
opens the exhaust port 50.
[0041] As the piston moves downward the air inlet port 98 and
charge inlet port 84 are closed by the piston. As the piston
continues to move down toward BDC, the exhaust port 50 is now open
for exhausting the burned gases and a few degrees later the
transfer ports 33 are open for scavenging and filling processes.
Since air is stored in the transfer passages, the air enters the
combustion chamber 30 first and tends to escape with the burnt gas.
The fresh charge follows the air and thus scavenging is
accomplished.
[0042] Also, it should be noted that an electronic LPG fuel
injection system may be used in place of a carburetor in some
embodiments.
[0043] In various embodiments, an intake system may be one of a
one-way valve type, or a rotary valve type. In the rotary intake
system, the intake port 84 is in the crankcase 28 and the intake
port 84 is opened and closed by a cut out in the crank web 21.
[0044] FIG. 5 illustrates an engine 1500 which is similar to engine
10 illustrated in FIG. 2, but has an LPG electronic fuel injection
(LPG EFI) system 9400 in place of the carburetor 34. The engine
1500 has the LPG EFI system 9400 to manage the delivery of gaseous
fuel 9101 to the engine 1500. The amount of fuel and timing of the
LPG fuel injection is controlled by an ECM 9142 mounted on the
throttle body 9102. The LPG EFI system manages the fuel delivery
based on inputs that the ECM 9138 receives from many sensors;
throttle position sensor 9142 that indicates if the throttle is
closed or open or any position in between idle and fully open
position, the engine speed or the RPM is measured by the number of
pulses the ignition module 9404 receives from the magnet on the
flywheel 9429, the air intake temperature as measured by the sensor
9146, and possibly engine block temperature. These are very
commonly used parameters in an EFI system commonly used in
automobiles. The LPG fuel 9101 is supplied from the LPG tank 2700,
which is normally at about 110 inches of water. The high pressure
fuel is typically reduced to about 10 to 15 inches of water and may
be even higher. The pressure regulator 2917 reduces the pressure.
The LPG pressure regulator may also be an integral part of the
throttle body 9400 as shown in FIG. 6.
[0045] The ignition module 9404 is mounted on boss 1012, and the
magnets (not shown) are on the flywheel 9429, which energize coils
in the ignition module. There may be additional power coil in the
module to supply power to the ECM 9136. The flywheel 9429 is
mounted on the crankshaft 22. The crankshaft 22 is used to drive
many applications, such as trimmers, blowers, chainsaws, mopeds,
lawn mowers, etc.
[0046] The engine 1500 may have oil injection as in the case of
engine shown in 5. The LPG EFI may also be used to inject the LPG
fuel directly into the crankcase chamber 26. The intake passage
shown in FIG. 5, has an LPG fuel injector in the charge intake
passage 312, while the oil is also injected into passage 312. In
some embodiments, the oil may be injected into the air passage 313.
In some embodiments, oil may be injected directly into the crank
case chamber. An oil injector 101 according to some embodiments is
illustrated in FIG. 5.
[0047] FIGS. 6 and 7 illustrate embodiments of electronically
controlled LPG or compressed natural gas injected throttle body as
applied to small engines. The pressure in an LPG tank typically is
about 100 inches of water and the pressure is reduced in regulator
to about 10 inches of water. The LPG EFI system 9400 consists of a
throttle body 9102 that has a primary intake passage 9180 that
connects the engine's charge intake passage 312 shown in FIG. 5.
The primary intake passage 9180 has a throttle valve 9162 which is
a butterfly valve (or which could be a slide valve or a rotary
valve) to regulate the amount of air going into the crankcase
chamber 26. The throttle valves (which may also generally be
referred to as control valves) 9162 and 9432 are controlled by the
throttle shaft 9584 or it can be a rotary valve or a sliding valve
as known in the art. In various embodiments, the control valves may
be in a single body. In various embodiments, the control valves may
be on separate bodies. In the latter case, the two separate bodies
may be fastened together. The LPG EFI system 9400 has an electronic
control unit 9136, commonly called an ECU or ECM mounted on the
body 9102 such that the throttle shaft 9584 passes through the ECU
9136 which has a throttle position sensor 9142 to sense the
position of the throttle, which can range from fully closed for low
speed and load at idle, to fully open position at full speed or
load. The ECU 9136 has inputs or sensors connected to it to measure
engine speed 9148, engine block temperature or exhaust temperature
9150, intake air temperature 9146. The ECU 9136 has the fuel and
timing maps to control the amount of LPG fuel 9102 injected through
an injector 9138 and also the ECU 9136 can control the spark timing
based on engine RPM and throttle position, which is a common
practice.
[0048] In some embodiments, the electronic control unit 9136 may be
mounted on or in close proximity to the injector 9138. As such,
terminals 9140 may be short. In some embodiment, there may be no
need for terminals 9140 as the electronic control unit may be in
direct contact with the injector.
[0049] Throttle body 9102 has an integral pressure regulator 9103
consisting of an LPG fuel inlet 9110, pressure chamber 9105,
diaphragm 9107, needle valve 9111, arm 9108, pressure spring 9109,
vent hole 9129 in the pressure regulator cover 9127.
[0050] The pressure P1 is normally at about 50 to 100 inches of
water in the LPG tank when the LPG fuel 9101 enters the pressure
chamber 9105 where the flow is regulated by the needle valve 9111.
The needle valve 9111 is connected to the diaphragm 9107 through a
pin 9118 and an arm 9108. As the pressure increases in the chamber
9105 the needle valve closes the flow of LPG fuel because the
pressure pushes the diaphragm 9107 outward against a pressure
spring 9109. The pressure P2 in the pressure chamber 9105 is
controlled by the spring 9109, which may be pre-set to any level
equal to or below the inlet pressure P1. The fuel pressure chamber
9105 is connected to a fuel metering chamber 9104 through a passage
9176 between the pressure chamber 9105 and the fuel metering
chamber 9116. The metering chamber 9116 is connected to the LPG
fuel injector 9138 through a fuel passage 9126, which can also be
an external hose outside the throttle body 9102. As the fuel flows
into the fuel metering chamber 9116, the pressure P2 in the
pressure chamber 9105 drops, thus opening the needle valve 9111 for
the fuel to flow into the pressure chamber 9105, thus maintaining
almost a constant pressure P2.
[0051] The fuel metering chamber 9116 also includes a diaphragm
9114, needle valve 9122, arm 9124, pin 9118, metering chamber cover
9130 and a vent hole 9128. Operation of the metering chamber 9116
is similar to the pressure chamber 9105, where the pressure P2 now
at about 10 inches of water is maintained constant while the fuel
is fed to the fuel injector 9138. LPG Fuel in the metering chamber
9116 is connected to the injector 9138 through a fuel passage 9126,
as the fuel is depleted in the metering chamber 9116 due to LPG
fuel injection into the passage 9180, the pressure P2 drops in the
metering chamber. The needle 9122 opens and maintains a nearly
constant pressure P2. The needle valve 9122 is activated by the
diaphragm through the pin 9118 and the arm 9124. The needle valve
tries to stay closed because of the spring 9120 in the metering
chamber 9116. Typically this spring 9120 is a very small spring
compared to the spring 9109. Pressure P2 in metering chamber 9116
is slightly lower than P2 due to pressure loss across the needle
valve 9122.
[0052] The amount of LPG fuel 9101 injected depends on throttle
position, intake temperature TI, engine block or exhaust gas
temperature TB, engine speed RPM, and sometimes, intake manifold
pressure MAP. In addition, a fuel inlet pressure or fuel pressure
(P4) in the LPG supply line may be input to the ECM so as to adjust
the on time of the fuel injector. Fuel supply pressure may be
important when the fuel tank is almost empty and that a longer on
time may be required to completely empty the fuel tank.
[0053] Typically, the EFI system requires a TDC or a crank angle
sensor to determine when the injection should occur or spark should
occur in a cycle. In a two-stroke engine, the spark occurs every
rotation of the crankshaft and also fuel injection occurs every
rotation of the crankshaft. Therefore, the fuel injection timing
may be tied to the spark timing, with appropriate lag time for
injection.
[0054] In FIG. 6, the fuel supply line 2927b from the LPG fuel tank
2700 has a fuel shut off valve 9192 that also is an electrical kill
switch to kill the running engine. This is a safety measure, where
the operator shuts off the fuel when he turns the switch to kill
the engine. The kill wires 9194 turns off the circuit in the ECU to
kill the engine. For certain type of applications, it is necessary
to have the engine kill switch on the handle. FIG. 6 also shows a
fuel pressure sensor 9152 to sense the fuel pressure and may be
input to the ECM 9136 to appropriately adjust the fuel on time.
Where the on time is longest at lower pressures. This normally
occurs when the fuel is almost empty in the LPG fuel tank. Sensor
may be necessary since there is no fuel pump in this case.
[0055] FIG. 9 illustrates an exemplary embodiment in which the air
channel 96 includes two branches, with each branch feeding air to
different transfer passages, e.g., to transfer passages on opposite
sides of the pin 200. In some embodiments, the extra branch may
take the place of a cutout along the edge of the piston, e.g., as
shown in FIG. 1. As depicted, the terminus of one of the branches
is referred to as a "tenth" port. It will be appreciated that, in
various embodiments, air passage 96 may include two or more
branches, or that there may be two or more air passages. It will be
appreciated that in various embodiments, multiple branches and/or
multiple passages may feed air to transfer passages either on the
same or on opposite sides of pin 200.
[0056] In some embodiments, a reed valve is used to admit ambient
air into a transfer passage, e.g., transfer passage (11b').
[0057] The following are embodiments, not claims:
Embodiment A
[0058] A two-stroke internal combustion engine comprising: [0059]
a. at least one transfer passage (11a) between a crankcase chamber
(26) and a combustion chamber (30) of the engine; and [0060] b. an
air channel (100) in gaseous communication with a top portion of
the at least one transfer passage (11) and ambient through at least
one air intake port (98).
Embodiment B
[0061] The two-stroke internal combustion engine of Embodiment A,
further comprising: [0062] a cylinder having a cylinder wall (14);
and [0063] a reciprocating piston (16) mounted within the cylinder,
[0064] wherein the piston has a air channel (96) and a window
(100a) that reciprocatingly establishes gaseous communication
between the at least one transfer passage (11a) and the air inlet
port (98).
Embodiment C
[0065] The two-stroke internal combustion engine of Embodiment B,
wherein the piston further comprises an air channel (96)
substantially perpendicular to the crankshaft (22).
Embodiment D
[0066] The two-stroke internal combustion engine of Embodiment A,
wherein the charge inlet port (84) is substantially in line with
the crankshaft (22).
Embodiment E
[0067] The two-stroke internal combustion engine of Embodiment A,
wherein the exhaust port (50) is substantially in line with the
crankshaft (22).
Embodiment F
[0068] An internal combustion engine as in Embodiment A further
comprising: [0069] a crankcase cover (28) covering a crankcase
chamber (26) within the crankcase (28); and [0070] a fuel tank
(2007) operable for holding liquefied petroleum gas or another
compressed gaseous fuel supplying fuel to the engine.
Embodiment G
[0071] An internal combustion engine as in Embodiment A further
having: a fuel tank (2007) operable for holding liquefied petroleum
gas (9101) or other compressed gaseous fuel for use in the engine,
an LPG EFI system (9400) comprised of a throttle body (9102) with
integral pressure chamber (9105) and LPG fuel metering chamber
(9116), having an electronically controlled LPG fuel injector
(9138), controlled by an ECM (9136), power supplied to ECM by coil
in the ignition module (9404), throttle position sensor (9142)
operated by the throttle shaft (9584).
Embodiment H
[0072] An internal combustion engine as in Embodiment G further
having: a LPG fuel tank (2007) operable for holding liquefied
petroleum gas (9101) or other compressed gaseous fuel for use in
the engine, an LPG EFI system (9400) comprised of a throttle body
(9102) with integral pressure chamber (9105) and LPG fuel metering
chamber (9116), having an electronically controlled LPG fuel
injector (9138) injecting into primary passage (9180), controlled
by an ECM (9136), power supplied to ECM by coil in the ignition
module (9404), throttle position sensor (9142) operated by the
throttle shaft (9160 or 9584) having dual throttle valves (9162 and
9432) one (9432) exclusively for controlling the amount of air only
and the other (9432) for controlling the amount of charge (Air plus
LPG Fuel or gaseous fuel).
Embodiment I
[0073] An internal combustion engine as in embodiment A further
having an LPG electronic fuel injection system (9400) comprising an
ECM (9136) to: [0074] a. control the timing and on time of the
injector (9138) with reference to spark timing or crank angle
position; [0075] b. control the spark timing and trigger the spark;
[0076] c. control the fuel injection duration; [0077] d. receive
the crank location signal from ignition coil (9404); [0078] e.
receive fuel pressure signal from the pressure sensor (9152);
[0079] f. adjust the injection duration based on the input from
throttle position sensor, engine speed (RPM), temperatures; [0080]
g. adjust the injection duration based on fuel pressure; [0081] h.
determine the stroke of the cycle based on spark interval at
starting; [0082] i. determine the start of injection timing based
on signal received from the ignition coil (9404); and [0083] j. to
receive power from the ignition coil (9404).
Embodiment J
[0084] The two-stroke internal combustion engine of Embodiment A,
wherein the oil is injected into the charge inlet passage (312) and
air induction into air inlet passage 313 is substantially free of
any fuel.
Embodiment K
[0085] The two-stroke internal combustion engine of Embodiment I,
wherein the fuel injected is LPG fuel.
Embodiment L
[0086] The two-stroke internal combustion engine of Embodiment I,
wherein the fuel injected is gaseous fuel.
Embodiment M
[0087] The two-stroke internal combustion engine of Embodiment I,
wherein the fuel is substantially free of any lubricating oil.
Embodiment N
[0088] The two-stroke internal combustion engine of Embodiment I,
wherein the fuel is pre-mixed with oil.
Embodiment O
[0089] The two-stroke internal combustion engine of Embodiment A,
wherein the charge inlet port (84) is in the crankcase (28) (not
shown in any FIG.).
MORE EMBODIMENTS
Embodiments
[0090] The following are embodiments, not claims:
[0091] Various embodiments include an engine with one transfer
passage that is opposite an air intake port. A passageway through
the piston may connect the air intake port to the transfer passage,
thereby putting the two in gaseous communication, at least some of
the time.
[0092] A. An engine (10) comprising: [0093] a) a hollow crankcase
(28); [0094] b) a hollow cylinder (12) opening at one end into the
opening of crankcase, the cylinder including: [0095] at least one
first port (98) for the admission of air; [0096] a second port (84)
for the admission of a mixture of air and fuel; and [0097] a third
port (50) for the expulsion of exhaust gasses; [0098] c) a piston
(16) situated within the cylinder (12), in which: the piston (16)
is free to move up and down along an axial dimension of the
cylinder (12); and [0099] the piston (16) substantially fills a
cross-sectional area of the cylinder (12) so as to substantially
divide the volume of the cylinder into a combustion chamber(30) on
one side of the piston and a crankcase chamber (26) on the other
side of the piston; [0100] d) a piston pin (200) that is attached
to the piston (16), in which the long axis of the pin lies
substantially perpendicular to the direction of motion of the
piston; [0101] e) a crankshaft (22) extending through the crank
case (28); [0102] f) a crank web (21) attached at its center to the
crankshaft; [0103] g) a connecting rod (18), in which one end of
the connecting rod is attached to the piston pin (200) and the
other end of the connecting rod (18) is attached to the crank pin
(20) on the crank web (21); and [0104] h) an ignition source (1005)
operable to supply ignition to the combustion chamber (30), [0105]
in which the engine translates up and down motion of the piston
(16) into a circular motion of the crankshaft (22) via the
intermediation of connecting rod (18) and crank web (21); [0106] in
which the cylinder includes at least one first transfer passage
(11b') with at least one fourth port (33a') opening into the
combustion chamber (30), and at least one fifth port (1122) opening
into the crankcase chamber (26); [0107] in which the piston (16)
includes at least one first passageway (96) through its interior
with a sixth port (99a) opening to one side of the long axis of the
piston pin (200) and a seventh port (99b) opening to the other side
of the long axis of the piston pin, such that at a given position
of the piston (16), the sixth port (99a) interfaces to the first
port (98) and the seventh port (99b) interfaces to the fourth port
(33a'); and [0108] in which the first passageway (96) is
substantially perpendicular to the piston pin (200).
[0109] AAXX. An engine (20) comprising: [0110] a) a hollow
crankcase (28) having a second port (84) in the crankcase; [0111]
b) a hollow cylinder (12) opening at one end into the opening of
crankcase, the cylinder including: [0112] at least one first port
(98) for the admission of air; and [0113] a third port (50) for the
expulsion of exhaust gasses; [0114] c) a piston (16) situated
within the cylinder (12), in which: [0115] the piston (16) is free
to move up and down along an axial dimension of the cylinder (12);
and [0116] the piston (16) substantially fills a cross-sectional
area of the cylinder (12) so as to substantially divide the volume
of the cylinder into a combustion chamber(30) on one side of the
piston and a crankcase chamber (26) on the other side of the
piston; [0117] d) a piston pin (200) that is attached to the piston
(16), in which the long axis of the pin lies substantially
perpendicular to the direction of motion of the piston; [0118] e) a
crankshaft (22) extending through the crank case (28); [0119] f) a
crank web (21) attached at one of its ends to the crankshaft;
[0120] g) a connecting rod (18), in which one end of the connecting
rod is attached to the piston pin (200) and the other end of the
connecting rod (18) is attached to the crank pin (20) on the crank
web (21); and [0121] h) an ignition source (1005) operable to
supply ignition to the combustion chamber (30), [0122] in which the
engine translates up and down motion of the piston (16) into a
circular motion of the crankshaft (22) via the intermediation of
connecting rod (18) and crank web (21); [0123] in which the
cylinder includes at least one first transfer passage (11b') with
at least one fourth port (33a') opening into the combustion chamber
(30), and at least one fifth port (1122) opening into the crankcase
chamber (26); [0124] k) in which the piston (16) includes at least
one first passageway (96) with a sixth port (99a) opening to one
side of the long axis of the piston pin (200) and a seventh port
(99b) opening to the other side of the long axis of the piston pin,
such that at a given position of the piston (16), the sixth port
(99a) interfaces to the first port (98) and the seventh port (99b)
interfaces to the fourth port (33a'); and [0125] (l) in which the
first and third ports are situated such that the direction of flow
of air through the first port, and the direction of flow of exhaust
gas through the third port are substantially perpendicular.
[0126] AA. An engine (20) comprising: [0127] a) a hollow crankcase
(28) having a second port (84) in the crankcase; [0128] b) a hollow
cylinder (12) opening at one end into the opening of crankcase, the
cylinder including: [0129] at least one first port (98) for the
admission of air; and [0130] a third port (50) for the expulsion of
exhaust gasses; [0131] c) a piston (16) situated within the
cylinder (12), in which: [0132] the piston (16) is free to move up
and down along an axial dimension of the cylinder (12); and [0133]
the piston (16) substantially fills a cross-sectional area of the
cylinder (12) so as to substantially divide the volume of the
cylinder into a combustion chamber (30) on one side of the piston
and a crankcase chamber (26) on the other side of the piston;
[0134] d) a piston pin (200) that is attached to the piston (16),
in which the long axis of the pin lies substantially perpendicular
to the direction of motion of the piston; [0135] e) a crankshaft
(22) extending through the crank case (28); [0136] f) a crank web
(21) attached at one of its ends to the crankshaft; [0137] g) a
connecting rod (18), in which one end of the connecting rod is
attached to the piston pin (200) and the other end of the
connecting rod (18) is attached to the crank pin (20) on the crank
web (21); and [0138] h) an ignition source (1005) operable to
supply ignition to the combustion chamber (30), [0139] in which the
engine translates up and down motion of the piston (16) into a
circular motion of the crankshaft (22) via the intermediation of
connecting rod (18) and crank web (21); [0140] in which the
cylinder includes at least one first transfer passage (11b') with
at least one fourth port (33a') opening into the combustion chamber
(30), and at least one fifth port (1122) opening into the crankcase
chamber (26); [0141] k) in which the piston (16) includes at least
one first passageway (96) through its interior with a sixth port
(99a) opening to one side of the long axis of the piston pin (200)
and a seventh port (99b) opening to the other side of the long axis
of the piston pin, such that at a given position of the piston
(16), the sixth port (99a) interfaces to the first port (98) and
the seventh port (99b) interfaces to the fourth port (33a'); and
[0142] l) in which the first passageway (96) is substantially
perpendicular to the piston pin (200).
[0143] A.l The engine (10) of embodiment A in which the at least
one first passageway (96) includes two separate passageways through
the interior of the piston, each interfacing at one end to the
first port (98) and at the other end to the fourth port (33a').
[0144] A.k The engine (10) of embodiment A in which: [0145] the
first passageway (96) is substantially perpendicular to the piston
pin (200); and [0146] the third port (50) lies along a radial line
of the cylinder (12) that is substantially parallel to the long
axis of the piston pin (200).
[0147] A.k.1 The engine (10) of embodiment A further comprising a
second passageway (313) for feeding air into the first port (98),
in which the second passageway (313) is substantially perpendicular
to the piston pin (200).
[0148] A.k.1.1 The engine (10) of embodiment A.k.1 in which the
first port (98) and the third port (50) are more than 90 degrees
apart with respect to the arc of the cylinder.
[0149] The engine (10) of embodiment A.k.1 in which the first port
(98) and the third port (50) are more than substantially
perpendicular with respect to the direction of flow of air and
exhaust gas respectively.
[0150] A.k.1.1 The engine (10) of embodiment A.k.1 in which the
first and third ports are situated such that the direction of flow
of air through the first port, and the direction of flow of exhaust
gas through the third port are substantially perpendicular.
[0151] A.k.1.2 The engine (10) of embodiment A.k.1 in which the
first port (98) and the third port (50) are less than 90 degrees
apart with respect to the arc of the cylinder.
[0152] A.k.2 The engine (10) of embodiment A in which the first
port 98 and the second port 84 both lie in the same quadrant of the
cylinder (12), where such quadrant is defined by a first radial
boundary parallel to the long axis of the piston pin (200) and
crossing the first passageway 96, and a second radial boundary
perpendicular to the long axis of the pin (200).
[0153] A.k.2' The engine (10) of embodiment A in which the first
port 98 and the second port 84 both lie at least partially in the
same quadrant of the cylinder (12), where such quadrant is defined
by a first radial boundary parallel to the long axis of the piston
pin (200) and crossing the first passageway 96, and a second radial
boundary perpendicular to the long axis of the pin (200).
[0154] A.0 The engine (10) of embodiment A in which the first
passageway (96) facilitates the admission of air into the transfer
passage (11b').
[0155] A.1 The engine (10) of embodiment A in which the first
passageway (96) is substantially perpendicular to the long axis of
the piston pin (200).
[0156] A.1.1 The engine of embodiment A in which the first
passageway (96) is substantially perpendicular to the axis along
which the piston (16) is free to move.
[0157] Various embodiments include engines with more than one
transfer passage, e.g., with two transfer passages.
[0158] A.2 The engine (10) of embodiment A further including a
second transfer passage (11a') with an eighth port (33a) opening
into the combustion chamber (30) and a ninth port (1123) opening
into the crankcase chamber (26).
[0159] Various embodiments include engines with more than two
transfer passages, e.g., four transfer passages. [0160] A.2.0 The
engine (10) of embodiment A.2 further including a third transfer
passage 11a'' and a fourth transfer passage 11b'', each with
openings into the combustion chamber (30) and the crankcase chamber
(26).
[0161] A.2.1 The engine of embodiment A.2 in which the eighth port
(33a) is on the opposite side of the long axis of the pin as is the
fourth port.
[0162] A.2.1.1 The engine of embodiment A.2 in which the eighth
port (33a) is on the right side of the long axis of the pin, while
the fourth port (33a') is on the left side of the long axis of the
pin.
[0163] In various embodiments, a piston may include a cavity (e.g.,
cavity 100a) that connects the air intake to the second transfer
passage (e.g., to the transfer passage on the near side of the
piston).
[0164] A.2.2 The engine of embodiment A.2 in which the piston (16)
includes a cavity (window 100a) that is connected to the first
passageway (98), and that, for a given position of the piston (16),
interfaces to the eighth port (33a).
[0165] A.2.2.1 The engine of embodiment A.2.2 in which the piston
(16) includes a deflector (1023) that directs airflow from the
first port (98) into two streams flowing, respectively, towards the
fourth and eighth ports.
[0166] In various embodiments, rather than a cavity, another
passageway, or e.g., a branched passageway, may connect the air
intake to the second transfer passage.
[0167] A.2.3 The engine (10) of embodiment A.2 in which the first
passageway (96) includes a tenth port and in which, for a given
position of the pin, the tenth port interfaces to the eighth
port.
[0168] A.2.3.1 The engine of embodiment A.2.3 in which the first
passageway is branched with one branch terminating at the seventh
port and the other branch terminating at the eighth port.
[0169] In various embodiments, where a passageway through the
piston is branched, a deflector may redirect some or all air to
ensure the air goes down both of the branches of the
passageway.
[0170] A.2.3.2 The engine of embodiment A.2.3 in which the first
passageway includes a deflector that directs air flow to the tenth
port.
[0171] A.2.3.3 The engine of embodiment A.2.3 in which the first
passageway includes a deflector that divides air flow entering from
the first (98) port into two streams flowing, respectively, towards
the seventh (99b) and tenth ports.
[0172] A.2.3.4 The engine of embodiment A.2.3 in which the first
passageway (96) includes a deflector that divides air flow entering
from the first port (98) into two substantially equal air streams
flowing, respectively, towards the seventh and tenth ports.
[0173] In some embodiments passageways 312 and 313 are
substantially perpendicular to the exhaust passage (50a), that is
to the direction of flow of exhaust gas.
[0174] A.x The engine (10) of embodiment A further comprising:
[0175] l) a second passageway (313) for feeding air into the first
port (98); [0176] m) a third passageway (312) for feeding a mixture
of air and fuel into the second port (84); and [0177] n) an exhaust
passage (50a), [0178] in which the both the second and third
passageways are substantially perpendicular to the exhaust passage
(50a).
[0179] A.x.1 The engine (10) of embodiment A.x in which the first
port (98) and the second port (84) lie less than 90 degrees from
one another along the arc of the cylinder (12).
[0180] A.x.1.1 The engine (10) of embodiment A.x.1 in which the
first port (98) and the second port (84) both lie more than 90
degrees from the third port when measured along the arc of the
cylinder (12).
[0181] A.x.2 The engine (10) of embodiment A.x in further including
an oil injector (101) for injecting oil into the third passageway
(312).
[0182] A.t The engine (10) of embodiment A in which fuel is not
pre-mixed with oil.
[0183] In some embodiments, ports 98 and 84 are in the quadrant 1,
between ports 33a and 33a'. An exemplary illustration of a division
of an engine into notional quadrants is shown in FIG. 8.
[0184] A.y The engine (10) of embodiment A further comprising:
[0185] l) a second passageway (313) for feeding air into the first
port (98); [0186] m) a third passageway (312) for feeding a mixture
of air and fuel into the second port (84), in which the first port
(98) and the second port (84) both lie in the same quadrant of the
cylinder (12), where such quadrant is defined by a first radial
boundary parallel to the long axis of the piston pin (200) and
crossing the first passageway 96, and a second radial boundary
perpendicular to the long axis of the pin (200).
[0187] A.y' The engine (10) of embodiment A further comprising:
[0188] l) a second passageway (313) for feeding air into the first
port (98); [0189] m) a third passageway (312) for feeding a mixture
of air and fuel into the second port (84), [0190] in which the
first port (98) and the second port (84) both lie at least
partially in the same quadrant of the cylinder (12), where such
quadrant is defined by a first radial boundary parallel to the long
axis of the piston pin (200) and crossing the first passageway 96,
and a second radial boundary perpendicular to the long axis of the
pin (200), and [0191] in which the second port (84) lies partially
to either side of a radial line of cylinder (12) that is parallel
to the long axis of the piston pin (200).
[0192] A.z The engine (10) of embodiment A in which the first port
(98) and the second port (84) both lie in the same quadrant of the
cylinder (12), where such quadrant is defined by a first radial
boundary parallel to the long axis of the piston pin (200) and
crossing the first passageway 96, and a second radial boundary
perpendicular to the long axis of the piston pin (200).
[0193] In various embodiments, an engine may include a metering
apparatus, such as a carburetor.
[0194] A.3 The engine of embodiment A further comprising: [0195] a)
a metering apparatus; [0196] b) a second passageway (9480) for
transporting air from the metering device to the first port (98);
and [0197] c) a third passageway (9180) for transporting gaseous
fuel from the metering device to the second port (84)
[0198] F. A metering apparatus (9400 in FIGS. 5, 6, and 7)
comprising: [0199] a) a first passageway (9480) for transporting
air to a first port (98) of an engine; [0200] b) a second
passageway (9180) for transporting gaseous fuel to a second port
(84) of the engine; [0201] c) at least one pressure chamber; [0202]
d) a metering chamber; [0203] e) fuel is free of any oil; and
[0204] f) fuel is gaseous fuel.
[0205] J. A two-stroke engine comprising: [0206] a) a hollow
crankcase (28) including one opening; [0207] b) a hollow cylinder
(12) opening at one end into the opening of crankcase, the cylinder
including: [0208] at least one port (98) for the admission of air;
[0209] a second port (84) for the admission of a mixture of air and
fuel; and [0210] a third port (50) for the expulsion of exhaust
gasses; [0211] c) a piston (16) situated within the cylinder (12),
in which: [0212] the piston (16) is free to move up and down along
an axial dimension of the cylinder (12); and [0213] the piston (16)
substantially fills a cross-sectional area of the cylinder (12) so
as to substantially divide the volume of the cylinder into a
combustion chamber (30) on one side of the [0214] piston and a
crankcase chamber (26) on the other side of the piston; [0215] d) a
piston pin (200) that is attached to the piston (16), in which the
long axis of the pin lies substantially perpendicular to the
direction of motion of the piston; [0216] e) a crankshaft (22)
extending through the crank case (28); [0217] f) a crank web
attached at one of its ends to the crankshaft; [0218] g) a
connecting rod (18), in which one end of the connecting rod is
attached to the piston pin (200) and the other end of the
connecting rod (18) is attached to the crank pin (20) on the crank
web (21); and [0219] h) an ignition source (1005) operable to
supply ignition to the combustion chamber (30), [0220] in which the
engine translates up and down motion of the piston (16) into a
circular motion of the crankshaft (22) via the intermediation of
connecting rod (18) and crank web; [0221] in which the cylinder
includes at least one first transfer passage (11b') with a fourth
port (33a') opening into the combustion chamber (30), and a fifth
port (1122) opening into the crankcase chamber (26); [0222] in
which the fuel is not pre-mixed with fuel; and [0223] in which oil
is injected separately to lubricate the internal parts of the
engine.
[0224] In various embodiments, an engine may include a metering
apparatus, such as a carburetor.
[0225] A.3. A metering apparatus (9400 in FIGS. 5, 6, and 7)
comprising: [0226] a) a metering apparatus; [0227] b) a second
passageway (9480) for transporting air from the metering device to
the first port (98); [0228] c) a third passageway (9180) for
transporting gaseous fuel from the metering device to the second
port (84); and
[0229] F. A metering apparatus (9400 in FIGS. 5, 6, and 7)
comprising: [0230] a) a first passageway (9480) for transporting
air to a first port (98) of an engine; [0231] b) a second
passageway (9180) for transporting gaseous fuel to a second port
(84) of the engine; [0232] c) at least one pressure chamber; [0233]
d) at least one metering chamber; and [0234] e) a fuel injector
(9138) injecting gaseous fuel into second passageway (9180).
[0235] F''. A metering apparatus (9400 in FIGS. 5, 6, and 7)
comprising: [0236] a) a first passageway (9480) for transporting
air to a first port (98) of an engine; [0237] b) a second
passageway (9180) for transporting gaseous fuel to a second port
(84) of the engine; and [0238] c) at least one pressure chamber,
[0239] in which the fuel is a gaseous fuel and is free of any oil.
[0240] F'. A metering apparatus (9400 in FIGS. 5, 6, and 7)
comprising: [0241] a) a first passageway (9480) for transporting
air to a second third passageway (313) of an engine; [0242] b) a
second passageway (9180) for transporting gaseous fuel to a third
fourth passageway (312) of the engine; [0243] c) a pressure
chamber; and [0244] d) a metering chamber.
[0245] F.1 The metering apparatus (9400) of embodiment F in which
the metering apparatus is a carburetor.
[0246] F.2 The metering apparatus (9400) of embodiment F in which
the metering apparatus is an electronic fuel injection system.
[0247] F.2.1 The metering apparatus (9400) of embodiment F in which
the metering apparatus comprises: [0248] a) at least one pressure
regulator (9103);
[0249] F.4 The metering apparatus (9400) of embodiment F in which
the gaseous fuel is one of: (a) liquefied petroleum gas; (b)
propane; (c) gaseous fuel consisting of methane gas; (d) hydrogen;
(e) landfill gas; and (f) natural gas.
[0250] A metering apparatus according to various embodiments may
have air and air-fuel controlling valves (9432 and 9162)
[0251] F.5 The metering apparatus of embodiment F further
comprising: [0252] a) a first control valve (9432) for controlling
flow of air into the first passageway; and [0253] b) a second
control valve (9162) for controlling flow of an air-fuel mixture
into the second passageway.
[0254] In various embodiments, valves may be either butterfly
valves, sliding valves, or rotating valves.
[0255] F.5.1 The metering apparatus of embodiment F.5 in which each
of the first and second control valves are one of: (a) butterfly
valves; (b) sliding valves; and (c) rotary valves.
[0256] F.5.1' The metering apparatus of embodiment F.5 in which
each of the first and second control valves are a combination of:
(a) butterfly valves; (b) sliding valves; and (c) rotary
valves.
[0257] F.5.2 The metering apparatus of embodiment F.5 in which the
first control valve and the second control valve are on a shaft
(9584).
[0258] F.5.3 The metering apparatus of embodiment F.5 in which the
first control valve is on a first shaft and the second control
valve is on a second shaft, in which the first shaft is different
than the second shaft.
[0259] In various embodiments, shafts may have a phase difference
between them. In some embodiments, the air valve may lag behind
air-fuel valve.
[0260] F.5.3.1 The metering apparatus of embodiment F.5.3 in which
each of the first and second control valves opens and closes
periodically at substantially the same frequency, but in which the
first control valve lags the second control valve.
[0261] F.5.4 The metering apparatus of embodiment F.5 in which the
first control valve and the second control valve are in a single
body.
[0262] F.5.5 The metering apparatus of embodiment F.5 in which the
first control valve is on a first body and the second control valve
is on a second body.
[0263] F.5.6 The metering apparatus of embodiment F.2 further
comprising an electronic control unit, in which the electronic
control unit is operable to: [0264] a) monitor a first state of an
engine; [0265] b) set a second state of the first control valve
based on the first state; and [0266] c) set a third state of the
second control valve based on the first state.
[0267] F.5.6.0 The metering apparatus of embodiment F.5.6, in
which, in monitoring the first state of the engine, the metering
apparatus is operable to monitor one or more of: (a) engine speed;
(b) temperature; (c) throttle position; (d) fuel pressure; (e)
engine temperature; (f) ambient temperature; and (g) spark
timing.
[0268] F.5.6.1 The metering apparatus of embodiment F.5.6, in which
the electronic control unit is further operable to monitor a
position of a throttle (9400) of the metering apparatus, and in
which the electronic control unit is operable to set the second and
third states based on a throttle position.
[0269] In various embodiments, the air passage and air-fuel
passages may be in an integrally cast body.
[0270] F.6 The metering apparatus of embodiment F in which the
first passageway and the second passageway are passageways through
an integrally cast body.
[0271] E. A metering apparatus comprising a single body, the single
body including: [0272] a) a first passageway (9480) for the
transport of air; [0273] b) a second passageway (9180) for the
transport of an air-fuel mixture; [0274] c) at least one pressure
regulator; and [0275] d) a metering chamber, [0276] in which the
fuel is not pre-mixed with oil; and the fuel is a gaseous fuel.
[0277] In various embodiments, a fuel metering apparatus may have
air and air-fuel passages (9480 and 9180) and an oil injector
(101), which may inject oil into the air-fuel passage (312).
[0278] H. A metering apparatus comprising: [0279] a) a first
passageway (9480) for the transport of air; [0280] b) a second
passageway (9180) for the transport of an air-fuel mixture; and
[0281] c) an oil injector (101) for injecting oil in the second
passageway.
[0282] In various embodiments, a fuel metering apparatus may have
air and air-fuel passages (9480 and 9180) and an oil injector
(101), which may inject oil into the air passage (313).
[0283] G. A metering apparatus comprising: [0284] a) a first
passageway (9480) for the transport of air; [0285] b) a second
passageway (9180) for the transport of an air-fuel mixture; and
[0286] c) an oil injector (101) for injecting oil in the first
passageway.
[0287] D. An apparatus comprising: [0288] a) a two-stroke engine
with a first port for admitting air and a second port for admitting
fuel; [0289] b) a metering apparatus, the metering apparatus
operable to generate a gaseous fuel mixture; [0290] c) a first
passageway for transporting air from the metering device to the
first port; [0291] d) a second passageway for transporting the
gaseous fuel mixture from the metering device to the second port;
and [0292] e) an oil injector (101) for injecting oil in the first
passageway.
[0293] I. A metering apparatus comprising: [0294] a) a throttle
body (9102) [0295] b) a first passageway for admitting air; [0296]
c) a second passageway for admitting gaseous fuel; [0297] d) an
electronic control unit (9136) mounted on the throttle body (9102);
and [0298] e) a gaseous fuel injector 9138 in the throttle body
(9102).
[0299] I.1 The metering apparatus of embodiment I in which the
apparatus does not have a metering chamber and does not have a
pressure chamber.
[0300] Various embodiments have been described in an illustrative
manner. It is to be understood that the terminology which has been
used is intended to be in the nature of words of description rather
than of limitation. While there have been described herein,
exemplary embodiments, other modifications shall be apparent to
those skilled in the art from the teachings herein and, it is,
therefore, desired to be secured in the appended claims all such
modifications as fall within the true spirit and scope of the
described and contemplated embodiments.
* * * * *