US2439379A

US2439379A - Water injection system for aircraft

Info

Publication number: US2439379A
Application number: US668051A
Authority: US
Inventors: Bergman Mendel
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-05-08
Filing date: 1946-05-08
Publication date: 1948-04-13
Anticipated expiration: 1965-04-13

Description

April 13, 1948. M. BERGMAN 'ATER INJECTION SYSTEH FOR AIRCRAFT Filed lay 8, 1946 J v www@ Bergman www' SEQ Smal @SQA SEQ heb mt 5382@ .ESG

FEES

Patented 13., l948 OFFICE ammo wA'rl-:n nunc'rrox srs'rmr ron Antolin-"rA Mendel Bergman, United States Navy Application MI! 8, 1948, Serial No. 868,051

'z 0mm. (ci. 12s-2s) (Granted under the act of March 8, 1883, as

amended April 30, 1928: 370 0. G. 757) This invention relates to improvements in the water injection system for aircraft and particularly to remedies for the present existing defects in the system.

The existing water injection system enables the pilot to obtain an increase of as much as 250 H. P. at full throttle for a limited period of timeV (eight to ten minutes). This extra horsepower is very useful in critical combat situations demanding extra power. The higher horsepower is obtained by leaning out the carburetor mixture and increasing the manifold pressure automatically when the pilot turns on the water injection system. Of the increase in power over military rating obtained with this emergency power;` approximately one half is due to the leaning out the mixture to best power and the other half due to the increase in manifold pressure. Ordinarily these changes would result in high cylinder temperatures and damage to the engine due to detonation, but when a ,water and alcohol mixture is introduced with the fuel at the impeller spinner nozzle, the cooling effect is suilicient to maintain normal cylinder temperatures and suppress any tendency toward detonation;

However, this previously existing water injection system i-s not intended for use during takeoil. Nevertheless it is necessary to point out the adverse conditions that will result from its inadvertent use. During normal operation of certain engines, the water discharge line becomes filled With fuel. This extra fuel is forced into the engine when the water injection equipment is actuated. The resultant excessively rich mixture causes the engine to hesitate or stumble for an instant. Pilots who have used water injection are familiar with this hesitation and an attempt to described its magnitude can not replace actual experience in flight. Obviously the use of water injection at the last moment before a crash appears imminent, will probably make the crash a certainty. i

If towards the end of take-oil run using takeoll' power, it is decided that additional power is necessary, the pilot must be extremely carefulnot to actuate the water injection `equipment; when increasing the power.' `In this connection it is necessary for pilots to familiarize themselves with the design and operation of the water injection equipment. They must be particularly careful that the pump of the master switch should be on the "oiT position-before the take-ofi', In certain cases, water injection is automatically obtained at full throttle. To avoid inadvertent use of water in these airplanes it is necessary that the safety wire on the throttle quadrant be replaced each time it is broken.

The purpose of this invention is to improve the operation oi' the conventional water injection system so that it will no longer be hazardous to accidentally operate the water injection system during take-oil. and to make it possible to use water injection for assisting heavily loaded airplanes to take-oil.' on a limited runway.

Details of the invention are described in connection with the following drawing in which the figure is a schematic, diagrammatic view of the improved features of this invention as added to the conventional existing water injection system.

When throttle valve control lever I is pushed to the wide open position breaking the safety l wire on the throttle quadrant the electric push button switch-2 which actuates the water injection system, closes the electric circuit to the water injection system and the following events occur:

Electrically operated pump 3 is started; ythe yelectric solenoid actuated valve I which is located near the entrance of water regulator 5 is opened and the vcircuit of the water quantity transmitter l is closed. A water pressure `of approximately 17.5 p. s. i. builds Vup almost instantly while the excess water, the vapor and air are returned to the water tank through bleed return line 'l on the upstream side of electric solenoid valve 4.

yThe water and alcohol solution -flows through open solenoid valve 4 and screen to water regulator 5. The water pressure opens check valve t at the entrance to the water regulator and builds up pressure in unmetered water chamber 9 of the water regulator. Two water lines lead from the unmetered water chamber of the water regulator; one of these indicated as I0 leads to the carburetor derichment "valve chamber II u where the water pressure leans out fuel mixture from approximately nine to one air-fuel ratioto approximately fourteen to `one air-fuel ratio.

The other. line indicated as I2 goes to the auxiliary supercharger regulator gate valve chamber L the carburetor to the main supercharger impeller.

Water enters the engine induction system with the fuel at approximately a ratio of one part of water to five parts of fuel. The first water to flow pushes the fuel in water regulator 5 and water transfer line I1 (which may back up as far as check valve 8 when the water pressure is oil) back to the supercharger or spinner discharge nozzle. This causes a momentary over rich mixture and the engine will hesitate briefly. Under normal conditions the engine will respond to the water injection system within three to five seconds after system is switched on.` As thus far described, this is the conventional existing'water injection system.

It has been found that the systemcan be improved by adding three items of this invention to the hookup of the conventional existing water injection system. These three additional items of this invention will allow the existing water injection system to be used for take-oil and their use is so designed to eliminate' the hesitation or stumble of the engine whenv water injection is used for take-on. An electric solenoid valve 20 is located at the banjo or water-regulator 5, the auxiliary supercharger regulator I4, and the derichment valve chamber This electric solenoid valve 20 is also connected to the push button switch 2 and is in parallel electrical hookup with the other electricsolenoid valve 4 located near the entrance to the water regulator. In order to maintain discharge nozzle pressure in the water, regulator 5, auxil, iary supercharger regulator i4, and derichment valve chamber it is necessary to install a low pressure accumulator 2| with an extremely exible diaphragm 22 on the side of the carburetor. One chamber 23 of the accumulator is connected to the fuel chamber of the carburetor having engine pump pressure, and the other chamber 24 oi.' the accumulator is connected to the derichment valve chamber of the carburetor. t

In addition, it is necessary to install a filler opening (vent) and plug 25 in the water chamber ofthe auxiliary supercharger regulator so that the auxiliary supercharger regulator, water regulator, and carburetor derichment valve chamber may (be filled and primed with the water-alcohol solution at the same time that the tanks of the Water injection system are filled dwith the water-alcohol solution.

After the water injection system has been turned' on, the pressure in the water-alcohol solution side 24 ofthe accumulator 2| will increase from the engine pump pressure (4 to 6 p. s. i.) to water pump pressure `(17.5 p. s. l.) and will therefor lmove the accumulator diaphragm 22 towards the fuel side 23 of the accumulator 2|. This will naturally force the fuel from 4the accumulator 2l into the chamber of the carbu' 4 5 carburetor to increase enough to open the poppet valve of the carburetor regulator unit any farther than necessary and therefore the correct mixture will be maintained.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What I claim is:

1. In an internal combustion engine carburetor i having a water injection system wherein fuel from the carburetor passes throughl a fuel transfer line to a double banjo or T fitting to mix with water passing through a water transfer line from the water injection system and then pass via the fitting through a mixture transfer line to the intake of the engine, and wherein fer line to a double banjo or T fitting to mix with water passing through a water transfer transfer. line and cause the engine to momentarily .lose power when the water injection system is line from the water injection system and'then pass via the fitting throughs mixture transfer line to the intake of the engine, and wherein the fuel, being lighter, tends to replace the water in the water transfer line and thus momentarily cause an ovenich fuel mixture to enter the mixture transfer line and cause the engine to momentarily lose power when the water injection system is first actuated; means for maintaining water in the water transfer line and prevent-ing the- -a solenoid valve in the-water transfer line located closely adjacent the banjo or T fitting.

- 3. In an internal combustion engine carburetor having a water injection system wherein fuel from the carburetor passes through a fuel transfer line to a double banjo T fitting to mix with water passing through a, water transfer linefrom the water injection system and then pass via the litt-ing through a mixture transfer line to the intake` of the engine, and wherein the fuel, being lighter, tends to replace the water in the water transfer line and thus momentarily cause an overrich fuel mixture to enter the mixture first actuated; and means for maintaining water in the 'water transfer line and preventing the fuel from replacing it while the water injection system is unactuated and means for actuating the water maintaining means to pass the water to the fitting simultaneously with the actuation of ,the water injection system and thus cause an immediate increase in engine power.

4. In an internal combustion engine carburetor `having a'water injection system wherein fuel from the carburetor passes through a. fuel transfer line to a double banjo or T fitting to mix with water passing through a water transfer line from the water injection system and then pass via the fitting through a mixture transfer line to the intake of the engine, and wherein the fuel, being maaar@ lighter, tends to replace the water in the water transfer line and thus momentarily cause an overrich fuel mixture to enter the mixture transfer line and cause the engine to momentarily lose power when the water injection system is first actuated; means for maintaining water in the `water transfer line and preventing the fuel from replacing it while the Water injection system is unactuated and means for actuatingthe water maintaining means to pass the water to the fitting simultaneously with the actuation of the water injection system and thus cause an immediate increase in engine power, said actuating means comprising a circuit connecting said solenoid valve to the circuit actuating the water injection system.

5. In an internal combustion engine carburetor having a water injection system wherein fuel from the carburetor passes through a fuel transfer line to a double banjo or TI tting to mix with water passing through a water transfer line from the` water injection system and then pass vla the fltunactuated and means for actuating the water maintaining means to pass the water to the fitting simultaneously with the actuation of the water injection system and thus cause an immediate increase in engine power, said actuating means comprising a circuit connecting said solenoid valve to the circuit actuating the water inlection system and vent or filler means in the water injection system.

6. In an internal combustion engine carburetor having a water injection system wherein fuel from the carburetor passes through a fuel transfer line to a double banjo or T fitting to mix with water passing through a water transfer line from the water injection system and then pass via the fitting through a mixture transfer line to lthe intake of the engine, and wherein the fuel,

being lighter, tends to replace the water in the water transfer line and thus momentarily cause an overrich fuelmixture to enter the mixture transfer line and cause the engine to momentarily lose power when the water injection system is first actuated; means for maintaining water in the water transfer line and preventingthefuel from replacing it while the water injection sys- Y tern is unactuated, means for actuating the water maintaining means to pass the Water to the fitmediatevincrease in engine power, said actuating means comprising a circuit connecting said solenoid valve to the circuit actuating the water injection system, and means for somewhat increasing the engine pump pressure of the carburetor comprising 4a differential pressure accumulator connected to the engine pump pressure chamber of the carburetor.

7. In an internal combustion engine carburetor having a water injection system wherein fuel from the carburetor passes through a fuel transfer line to a double banjo or T fitting to mix with water passing through a water transfer line from the water injection system and then pass via the fitting through a mixture transfer line to the intake of the engine, and wherein 'the fuel, being lighter, tends to replace the water in the water transfer line and thus momentarily cause an overrich fuel mixture to enter the mixture transfer line and cause the engine to momentarily lose power when the water injection system. is first actuated; means for maintaining water in the water transfer line and preventing the fuel from replacing it while the water injection system is unactuated, `said means comprising a solenoid valve in the water transfer line located closely adjacent the banjo or T fitting, and means for actuating f the water maintaining means to pass the water to the fitting simultaneously with the actuation of the water injection system and thus cause animmediate increase in engine power, said actuating means comprising a circuit connecting sai-d solenoid valve to the circuit actuating the water injection system. Y

MENDEL BERGMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS l France May 1s, 193s Certificate of Correction Patent No. 2,439,379. April 13, 1948.

MENDEL BERGMAN It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 2, line 46, after the Word regulator insert 14; column 8, lines 1 and 9, after nozzle insert valve; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the ease in the Patent JOfIce.

Signed and sealed this 8th day of June', A. D. 1948.

[SEAL] THOMAS F. MURPHY,

Assistant mmm'ssz'oner of Patents.