IL28507A

IL28507A - Supplemental fuel system

Info

Publication number: IL28507A
Application number: IL28507A
Authority: IL
Original assignee: Borg Warner
Priority date: 1966-08-25
Filing date: 1967-08-15
Publication date: 1970-12-24
Also published as: BE703096A; DE1576285B1; SE309880B; NL6711753A; ES344335A1; NL152062B; GB1176725A

Description

C O H E N^ Z E D E K & S P I S B A C H R EG D: PAT E N T AT TO R N EYS 24, LEVONTIN STR.. P. O. B. 1169 T E L - A V I V P A T E N T S & D E S I G N S O R D I N A N C E 16870/67 SPECIFICATION SUPPLEMENIA L FUEL SYSTEM BORO^IARNEH CORPORATION, a corporation duly organized and existing under and by virtue of the laws of the State of Illinois, having its principal office and place of business at 200 South Michigan Avenue, Chicago, Illinois, 60604, U.S.A., O HEREBY DECLARE the nature of this invention and in what manner the same is to be performed to be particularly described and ascertained in and by the following statement: SUPPLEMENTAL FUEL SYSTEM This invention relates to supplemental fuel systems for diesel engines. More particularly, it relates to an automatically controlled system which admits combustible gas into the intake air of a diesel engine to increase the power capabilities of the engine under high load.

It is well known that the power output of a diesel engine may be significantly increased by the addition of combustible gas into the engine intake air. Engine horsepower may be maintained with an accompanying decrease in the exhaust smoke or alternatively it may be increased (by as much as forty percent) without any appreciable increase in the exhaust smoke.

Several systems have been developed to accomplish the addition of combustible gas to diesel engine intake air. Most of these systems are controlled by, or are sensitive to, the setting of the engine throttle. Such arrangements are unable to appreciate differences in engine loading and therefore gas is admitted regardless of load and operation is not limited to high loads where the extra horsepower is most effective. Additionally, sudden changes in the throttle position result in surging of the supplemental gas which in turn causes irregular engine operation.

Attempts have been made to provide a throttle-controlled metering valve in the gas line to admit fuel proportionately with respect to throttle position. Such arrangements have proven to be quite difficult to install and to regulate by the operator.

It is therefore the principal object of the pre- provide an improved supplemental fuel system for a diesel engine which admits a supply of combustible gas into the engine intake air.

It is another object of the present invention to provide such a system which is operative to admit gas only at high engine loads.

It is another object of the present invention to provide such a system which automatically activates and deactivates independently of the throttle setting.

It is a related object of the present invention to provide such a system which automatically activates and deactivates in response to engine exhaust manifold temperature.

It is yet another object of the present invention to provide such a system which eliminates surging due to rapid institution or termination of the gas flow.

These and other objects and advantages- of the present invention will become more apparent with reference to the following description and accompanying drawing wherein FIGURE 1 is a schematic view showing a diesel engine in operative association with a supplemental fuel system illustrative of various of the features of the invention.

FIGURE 2 is a fragmentary schematic view of a modified form of the invention.

Referring now to the drawing and with particular reference to FIGURE 1 there is shown a diesel engine generally designated 11 provided with a supplemental fuel system 13. The diesel engine 11 includes an air intake system 15 and a combustion product exhaust system 17 both of which are generally typical of conventional diesel engines and J In this regard, the intake system includes an air filter 19 an intake duct 21 , and an intake manifold 23 and the exhaust system includes an exhaust manifold 2fj an exhaust duct 27 and a muffler . The engine includes a primary fuel system (not shown) which provides the diesel fuel needed for normal operation.

As seen in the drawing the supplemental fuel system 13 includes a source of combustible gaseous fuel 9 which is maintained at a regulated positive pressure by a regulator or the like (not shown). While such a regulated supply of gaseous fuel is desirable in that it prevents surging due to the relatively high supply tank pressures to which the system will be subjected if the regulator were not present, the scope of the invention contemplates any gaseous fuel system and the regulated supply is shown only for purposes of illustration. The system, further includes a regulator 31* a pressure control valve assembly 33 and a load sensing and control circuit generally designated 35. For purposes of illustration the fuel is considered to be LP (liquid petroleum) gas.' However, any suitable gaseous fuel may be used without departing from the scope of the invention.

The regulator 31 may be any of a number of commercially available demand regulators and it should be understood that the following description is only for the purpose of operational clarification. The regulator includes a hollow housing 37 within which is disposed a flexible diaphragm 39 which forms with the housing a high and a low pressure chamber 41 and 3.

A manifold pressure conduit 45 connects the low pressure chamber to the engine intake duct 21 for delivery used to adjust the maximum fuel flow through conduit 7.

A gas inlet pipe 7 also connects the chamber to the source of LP gas as supplied at a regulated pressure.

Pivotably mounted within the low pressure chamber is lever 49 which includes a valve cap 51 normally biased into an essentially gas-tight seal with gas J.nlet pipe 47 by a compressed spring 53. A lever arm 55 is movable with the diaphragm to provide a torque sufficient to open inlet pipe 47 as will be explained.

A solenoid valve assembly 57 is associated with inlet pipe 47 and is effective to stop gas flow when not activated and to maintain a supply of gas under pressure available at inlet pipe between the valve and valve cap 1 during normal operation.

The valve assembly 57 is energized through a series network including a power source 59 and a switch 58, which may be the running switch of the engine.

The pressure control valve assembly 33 defines a valve chamber 6l . A secondary pressure conduit 63 connects the chamber 6l with the manifold pressure conduit 45 , ending within chamber 6l in valve seat 65 . An atmospheric conduit 67 opens to the atmosphere through air filter 69 and connects the atmosphere with chamber 6l ending in a second valve seat 71 spaced directly opposite valve seat 65. A connecting conduit 73 also connects chamber 6l with high pressure chamber 41 in the regulator 31 . Both conduit 63 and conduit 67 include a flow nozzle 75 to restrict the rate of pressure signal response.

A generally annular pressure valve 77 of sufficient size to close either of the valve seats 65 or 71 is mounted between the valve seats arid in axial alignment with them. solenoid, when energized is effective to move valve 77 into sealing engagement with valve seat 65 when activated.

In its normal position thus described the supplementary fuel system conducts a pressure signal from intake duct 21 through manifold pressure conduit 45 to the low pressure chamber 3. Simultaneously, it conducts a pressure signal of the same magnitude through secondary pressure conduit 63 into valve chamber 6l , through connecting conduit 73 and into the high pressure chamber 41. Thus in normal · position there is an equal pressure on either side of diaphragm 39 and the diaphragm is essentially centered.

It is important to note that under this condition the valve cap 51 is in sealing engagement with the gas inlet pipe 47 to prevent the pressure condition existing within the chamber 43 from affecting the pipe 47. In this way gas is available as soon as the cap 51 is moved out of sealing engagement with the pipe 47.

In accordance with the present invention the supplementary fuel systeir. and the diesel engine are interconnected in such a way that gas is automatically admitted to .the intake duct 21 in response to increased engine load. It has been found that engine exhaust temperature as sensed, for example, in the exhaust conduit 27 gives a good indication of engine load. That is to say, as the load increases exhaust temperature increases and vice versa. Therefore, the electrical network 35 is provided which includes a temperature -sensitive switch 83 in the exhaust conduit.

The switch 83 which may include a bimetallic element or other temperature-sensitive component is connected in series with solenoid 79 and a voltage source 85 which may be the same source as source 59 · It is important to note that any As the exhaust temperature rises in response to increased engine loads, switch 83 closes activating the solenoid 79. In response, valve 77 breaks its seal with valve seat 71 and moves into sealing engagement with valve seat 65. When the valve is in this new position, chamber 6l of pressure control valve no longer receives a manifold pressure signal but rather receives an atmospheric pressure signal which is of relatively greater magnitude. The increased signal is conducted through connecting conduit 73 to high pressure chamber 41.

Since the low pressure chamber is still receiving a manifold signal, a pressure differential arises across the diaphragm 39 and the diaphragm moves downward. This movement causes lever arm 55 to engage lever 9 pivoting valve cap 51 away from the gas inlet pipe 47 and allowing gas to flow directly to the intake conduit 21 through the manifold pressure conduit 5. The gas there mixes with the incoming intake air to accomplish the desired power-boosting effect. When engine load drops the switch 83 will break the electrical network deactivating solenoid core 79 to return the supplementary fuel system to its normal position.

During transitions to and from the gas admittance condition, flow nozzles 75 cause the pressure signal moving through conduit 67 or 63 , respectively, to reach a controlled maximum rate of travel. This rate control prevents the free flow which would otherwise cause instantaneous opening or closing of the gas inlet pipe and the ensuing gas surge which has been characteristic of previous systems.

Referring now to FIGURE 2 , there is illustrated a modified form of the invention. In this arrangement all elements of the system are essentially the same as the system In this embodiment a secondary pressure conduit 63a, communicating with a manifold pressure conduit 45a, a connecting conduit 73a communicating with a regulator high pressure chamber (not shown) similar to the chamber 6l of FIGURE 1, and an atmospheric conduit 67a connected to an air filter 69a are connected to allow communication between the conduits as at 90.

A single acting pressure control valve assembly 33a is disposed in the conduit 67a. This valve assembly includes a valve 77a movable from a normally closed position preventing communication between the atmosphere and conduits 63a and 73a and an open position allowing communication to atmosphere through the conduit 67a.

The valve assembly 33a is energized by a temperature sensing circuit such as the circuit 35 of FIGURE 1 so that operation is similarly automatic and sensitive to engine load. When the valve assembly 33a is energized the valve 77a assumes its open position and allows communication between the conduit 67a and conduits 63a and 73a. Communi-cation of atmospheric pressure to conduit 73a exposes the high pressure chamber of the regulator (not shown) to a pressure differential as in the embodiment of FIGURE 1, thus supplying supplemental gaseous fuel to the engine air intake through conduit 5a.

It should be noted that in this arrangement when the valve assembly 33a is energized the valve 77a does not close conduit 63a and prevent communication to atmosphere. Therefore, a minute quantity or air may enter the engine intake system through conduit 63a.

As can readily be appreciated an improved supplemental fuel system has been shown and described which is problem of gaseous fuel surging when the system is activated or deactivated.

Various of the features of the invention have been particularly shown and described in connection with the illustrated embodiments of the invention. However, it must be understood that these particular arrangements merely illustrate and that the invention is to be given its fullest interpretation within the terms of the appended claims.

Claims

1. HAVING NOW particularly described and ascertained the nature of our said invention and in what manner the same is to he performed, we declare that WHAT r$®;,CLAIMim IS: ■ .1. A supplemental fuel system adapted to be oper-atively associated with- diesel engine including an intake system having an intake manifold which admits air from the atmosphere and an exhaust system which conducts exhaust from the engine, said supplemental fuel system comprising: a source of combustible gaseous fuel; a demand regulator defining a low pressure chamber and a high pressure chamber, a gas inlet pipe connecting said source of gaseous fuel to said low pressure chamber, said gaseous fuel being normally prevented from entering said low pressure chamber by means in said regulator, said means being responsive to a pressure differential between said high pressure chamber and said low pressure chamber to allow a gaseous fuel to enter said low pressure chamber; a manifold pressure conduit connecting said low pressure chamber to said intake system intake manifold and defining a passage for delivery of gas to said intake system; a secondary pressure conduit connected to said manifold pressure conduit; a connecting conduit connected to said high pressure chamber of said regulator, and an atmospheric conduit connected to the atmosphere; said secondary pressure conduit, said connecting conduit, and said atmospheric conduit being connected in communication with each other; an electrically operated pressure control valve assembly including a valve movable between a normally closed and an open position, said valve being disposed so as to prevent communication of atmosphere to said connecting conduit through said atmospheric conduit when in said nor-mally closed position, and allowing communication of atmosphere to said connecting conduit through said atmospheric conduit when in said open position,' thereby creating a said low pressure chamber and an electrical circuit including means responsive to engine load connected to said pressure control valve assembly, said circuit being effective to activate said pressure valve assembly in response to a predetermined load to move said valve to said open position.

2. A supplemental fuel system as claimed in Claim 1 wherein said electrical circuit includes a temperature sensitive switch adapted to be disposed in the engine exhaust system; said switch being effective to energize said pressure control valve in response to engine exhaust temperature.

3. A supplemental fuel system as claimed in claim 2 wherein said temperature -sensitive switch includes a bimetallic element.

4. A supplemental fuel system as claimed in claim 1 wherein said pressure control valve assembly valve is disposed in said atmospheric conduit. 5· A supplemental fuel system as claimed in claim 1 wherein said source of gas comprises LP (Liquid Petroleum) gas . 6. A supplemental fuel system as claimed in claim 1 wherein said secondary pressure conduit and said atmospheric conduit include flow nozzles effective to prevent surging of said gas . 7. A supplemental fuel system adapted to be oper-atively associated with a diesel engine including an intake system having an intake manifold which admits air from the atmosphere and an exhaust system which conducts exhaust from the engine, said supplemental fuel system comprising: a a gas inlet pipe connecting said gas source to said low pressure chamber, said gas being normally prevented from entering said low pressure chamber by means in said regulator; said means being responsive to a pressure differential between said high pressure chamber and said low pressure chamber to allow gaseous fuel to enter said low pressure chamber; a manifold pressure conduit connecting said low pressure chamber to said intake system intake manifold and defining a passage for delivery of gas to said intake system; an electrically-operated pressure control valve assembly defining a chamber; a secondary pressure conduit having a valve seat in said chamber, said secondary pressure conduit connecting said chamber to said manifold pressure conduit; a connecting conduit connecting said chamber to said high pressure chamber of said regulator; an atmospheric conduit having a valve seat in said chamber, said connecting conduit connecting said chamber to the atmosphere; said pressure control valve assembly including a valve biased in essentially sealing relation with said atmospheric valve seat when said assembly is deactivated and movable out of sealing relation with said atmospheric valve seat and into essentially sealing relation with said secondary pressure valve seat when activated thereby allowing communication of atmosphere to said connecting conduit to establish a pressure differential between said high pressure chamber and said low pressure chamber and additionally preventing communication of atmosphere to said secondary conduit allowing an electrical circuit including means responsive to engine load connected to said pressure control valve assembly, said circuit being effective to activate said pressure valve assembly in response to a predetermined load to effect said valve movement. 7 wherein said electrical circuit includes a temperature-sensitive switch adapted to be disposed in the engine exhaust system; said switch being effective to energize said pressure control valve in response to engine exhaust temperature. 9. A supplemental fuel system as claimed in claim 8 wherein said temperature-sensitive switch includes a bimet-element . 10. A supplemental fuel system as claimed in claim 7 wherein said source of gas comprises LP (Liquid Petroleum) gas0 11. A supplemental fuel system as claimed in claim 7 wherein said secondary pressure conduit and said atmospheric conduit include flow nozzles effective to prevent surging of said gas . 12. A supplemental fuel system adapted to be operatively associated with a diesel engine including an intake system having an intake manifold which admits air from the atmosphere and an exhaust system which conducts exhaust from the engine , said supplemental fuel system comprising; a source of combustible gaseous fuel; a demand regulator defining a low pressure chamber and a high pressure chamber, a gas inlet pipe connecting said source of gaseous fuel to said low pressure chamber, said gaseous fuel being normally prevented from entering said low pressure chamber by means in said regulator, said means bei'ng responsive to a pressure differential between said high pressure chamber and said low pressure chamber to allow a gaseous fuel to enter said low pressure chamber; a manifold pressure con of gas to said intake system; a secondary pressure conduit connected to said manifold pressure conduit; a connecting conduit connected to said high pressure chamber of said regulator, and an atmospheric conduit connected to the atmosphere; said secondary pressure conduit, said connecting conduit, and said atmospheric conduit being connected in communication with each other; a pressure control valve assembly including a valve movable between a normally closed and an open position, said valve being disposed so as to prevent communication of atmosphere to said connecting conduit through said atmospheric conduit when in said normally closed position, and allowing communication of atmosphere to said connecting conduit through said atmospheric conduit when in said open position, thereby creating a pressure differential between said high pressure chamber and said low pressure chamber and means responsive to engine load connected to said pressure control valve assembly effective to activate said pressure valve assembly in response to a predetermined load to move said valve to said open position. DATED THIS 14th da of ugusji^ig ? P.O.BOX 1169, TEIr-AVIV Attorneys for Applicants