Fluid injection system for internal combustion engine

A novel pump suitable for use in a water injection system of an internal combustion engine is described. The pump controls the rate of flow of water injected into the engine. The pump includes a variable pressure inducing means for pressurizing the water contained in the pump. The variable pressure inducing means is responsive to negative back pressure developed in the intake manifold of the engine and varies the pressure of the water in accordance with changes in the negative back pressure of the manifold. As the negative back pressure decreases, the pressure of the water increases which in turn increases the flow rate of fluid from the pump into the engine. There is also disclosed a pressure sensitive nozzle for controlling the flow of fluid exiting from the nozzle as a function of fluid pressure. The nozzle includes an auxiliary fluid flow path through the nozzle that has an inlet opening of variable size. The nozzle further includes a pressure sensitive piston that provides a primary fluid flow path through the nozzle. The pressure sensitive piston normally blocks the inlet of the auxiliary flow path. In response to a pressure build up above the predetermined value in the primary fluid flow path of the piston, the piston moves thereby increasing the size of the inlet of the auxiliary flow path as the pressure build up in the primary flow path increases above the predetermined value.

The present invention relates to a water injection system for injecting 
water into the intake of an internal combustion engine. In particular the 
present invention relates to a pump which is responsive to changes in a 
negative back pressure of the manifold and to a nozzle having a regulated 
orifice for controlling the amount of fluid injected into the engine. 
It has long been established that injection of water into the mixture of 
fuel and air in an internal combustion engine is advantageous. One 
advantage is the octane requirements of the fuel used in the engine may be 
reduced. Another advantage is that the water reduces the working 
temperature in a combustion chamber and cooling system of the engine. A 
further advantage is a reduction of pollutants in the byproducts of 
combustion. 
One water injection system presently on the market utilizes an electronic 
controller which switches on the pump to inject a fine spray of water into 
the carburetor airstream. The amount of water injected into the engine is 
controlled by the engine speed and the intake manifold negative back 
pressure. The electronic controller senses the engine speed and the 
negative back pressure and starts the operation of the pump when the 
engine reaches a predetermined speed and the negative back pressure 
reaches a predetermined amount. The control box changes water flow through 
the engine as the engine increases or decreases in speed. 
While the above system provides for controlled injection of water into the 
carburetor, the control is an electronic control. Further, the system does 
not provide a standard spray nozzle that may be readily used with engines 
of varying size. 
Another type of water injection system is disclosed in U.S. Pat. No. 
2,756,729 issued July 31, 1956, to H. D. Wolcott. In this patent, a valve 
device is provided to regulate the flow of water into the engine as a 
function of negative back pressure. The device includes two diaphragms 
each defining two sub-compartments. One of the two sub-compartments 
defined by each of the diaphragms is connected in continuous air flow 
communication with the engine manifold. The first diaphragm controls the 
amount of water flowing through the device by controlling the opening of 
two valves. As the negative back pressure decreases the first diaphragm 
opens the two valves in sequence. The second diaphragm carries a valve and 
closes the valve when the engine is stopped thereby preventing water from 
siphoning into the engine. This system however is expensive to manufacture 
and works on the principle of water draining from a reservoir through the 
device and into the manifold by siphonic action. 
It is therefore an object of the present invention to provide a pump that 
is adapted for use in a fluid injection system of an internal combustion 
engine which pump is responsive to changes in the negative back pressure 
in the engine manifold to regulate the rate of flow of fluid into the 
engine. 
It is another object of the present invention to provide a spray nozzle 
having a regulated orifice responsive to changes in pressure build up 
within the nozzle. 
In accordance with one aspect of the present invention there is provided a 
novel pump that is adapted for use with a fluid injection system of an 
internal combustion engine having an intake manifold. The pump controls 
the rate of flow of fluid injected into the engine and comprises a 
variable pressure inducing means for pressurizing the fluid contained in 
the pump. The variable pressure inducing means is responsive to changes in 
the negative back pressure in the manifold to vary the pressure of the 
fluid. The variable pressure inducing means increases the fluid pressure 
as the negative back pressure decreases. As a result, the flow rate of 
fluid from the pump into the engine increases. 
The variable pressure means may include a first diaphragm that divides a 
main chamber of the pump into two main sub-compartments. One of the main 
sub-compartments contains the fluid to be pressurized. The variable 
pressure inducing means may further include an actuating member for moving 
the diaphragm into an out of pressure inducing relation with the fluid. 
The pump may further include an auxiliary chamber into which the actuating 
member extends. The actuating member may be connected to a second 
diaphragm positioned within the auxiliary chamber so as to divide the 
auxiliary chamber into two auxiliary sub-compartments. One of the two 
auxiliary sub-compartments would be in air flow communication with the 
manifold such that the second diaphragm would vary its position, and the 
position of the actuating member, as the negative back pressure varies. 
The advantage of the pump of the present invention resides in the variable 
pressure including means being responsive to changes in the negative back 
pressure developed in the manifold. As a result an appropriate amount of 
fluid may be injected into the carburetor of the engine during changes in 
the operating conditions of the engine. 
In accordance with another aspect of the present invention there is 
provided a pressure sensitive nozzle having a regulated orifice for 
controlling the flow of fluid exiting therefrom as a function of fluid 
pressure. The nozzle includes an auxiliary fluid flow path extending 
through the nozzle. The auxiliary fluid flow path has an inlet opening of 
variable size. The nozzle further includes a pressure sensitive means 
providing a primary fluid flow path through the nozzle. The pressure 
sensitive means normally blocks the inlet of the auxiliary flow path but 
is movable in response to a pressure build up of a predetermined value in 
the primary fluid flow path. The pressure sensitive means moves in such a 
fashion to increase the size of the inlet of the auxiliary flow path as 
the pressure build up in the primary flow path increases above a 
predetermined value. As a result of the pressure sensitive means moving in 
response to a pressure build up a bigger channel is provided to allow more 
fluid to pass through the nozzle.

Referring to FIG. 1, there is illustrated a water injection system 10 
adapted for use with an internal combustion engine 12. The engine 12 
includes an air intake manifold 14. The engine 12 further includes a 
carburetor 16 schematically illustrated to the far right of FIG. 1. 
The water injection system 10 comprises a pump 18 shown in the central 
lower portion of FIG. 10. Pump 18 has an outlet 20 from which fluid flows 
when check valve 22 is open. Fluid passing through check valve 22 travels 
through piping 24 into spray nozzle 26. Spray nozzle 26 emits from its 
regulated output 28 a stream of water into the carburetor 16 of engine 12. 
Water enters the upper portion of pump 18 via piping 30. Piping 30 
provides a fluid flow path between the pump 18 and water reservoir 32. The 
end of pipe 30 extending into the water reservoir 32 includes a filter 34. 
Water reservoir 32 is provided with an electrical float 36. When the water 
in reservoir 32 is low, the electric float 36 provides an electrical path 
through its contacts which allows light 38 to turn on. The lower portion 
of pump 18 has a relief air valve 40 and an auxiliary chamber 42 connected 
in air flow communication with manifold 14 via air hose 44. 
During the operation of the engine 12, the temperature of the engine rises 
above a predetermined temperature value. When the engine temperature rises 
above this predetermined temperature value, thermal relay 46 closes. Prior 
to relay 46 closing a check valve 22 is closed thereby preventing the 
injection of water into the carburetor 16. Once the thermal relay 46 
closes, the electrical circuitry of the water injection system 10 becomes 
operable. In this regard energy through bistable switch 48 is provided. 
Prior to describing the operation of the water injection system 10, a 
detailed description of pump 18 is in order. Referring to FIGS. 2, 3 and 4 
in addition to FIG. 1, the pump is shown to basically comprise four 
housings. The first housing is the main housing 50 having attached thereto 
an auxiliary housing 42 and a housing for air relief valve means 40. The 
last housing is pressure maintaining housing 52 shown attached to the top 
of housing 50. 
The main housing 50 provides a main chamber 54. The diaphragm 56 positioned 
within chamber 54 divides the chamber into two sub-compartments 58 and 60. 
Diaphragm 56 is held in place between flanges 62 and washer 64 by means of 
screws and bolts 66. Fluid in the sub-compartment 58 will comprise water 
while the fluid in sub-compartment 60 is air. Water enters sub-chamber 58 
through inlet boss 68 which is illustrated as a one-way valve. Inlet 68 is 
connected to piping 30. Water exits the sub-compartment 58 through one-way 
valve 70 and enters the pressure maintaining housing 52. Pressure 
maintaining housing 52 is provided with pump outlet 20. As illustrated, 
the pressure maintaining housing 52 is provided with a holding chamber 72. 
A portion of the holding chamber 72 comprises water while the upper 
portion of holding chamber 72 includes air 74. The lower sub-compartment 
60 of the main chamber 54 is provided with an inlet 76. Depending on the 
position of valve 78 of air relief valve 40, inlet 76 is either in air 
flow communication with air port 80 or air port 82. The air port 80 is 
connected to the atmosphere and allows air under atmospheric pressure to 
enter sub-compartment 60. When port 82 is in air flow communication with 
inlet 76, the pressure within the sub-compartment 60 drops. This is 
because sub-compartment 60 will be in air flow communication with the 
manifold 14 and the negative back pressure developed in manifold 14. The 
auxiliary housing 42 of pump 18 includes an auxiliary chamber 84 
subdivided by diaphragm 85 into auxiliary sub-compartments 86 and 88. 
Diaphragm 85 is secured to the auxiliary housing 42 in much the same 
manner as diaphragm 56 is secured to the main housing 50. Auxiliary 
sub-compartment 86 is in air flow communication with main sub-compartment 
60 because of the air passageway 90 extending between these 
sub-compartments. The sub-compartment 88 is provided with a port 92 which 
is connected to air hose 44. Thus sub-compartment 88 is in continuous air 
flow communication with the negative back pressure developed in the 
manifold 14 of engine 12. 
Pump 18 further includes a pressure inducing means generally illustrated at 
94 that pressurizes the fluid contained with sub-compartment 58. The 
pressure inducing means 94 comprises diaphragm 56, actuating member or 
connecting rod 96, and spring means 98 attached to stud 100 and adjustable 
from the outside of the pump by adjustment means or nut 102. Nut 102 and 
stud 100 are adjusted such that spring 98 provides via connecting rod 96 
and diaphragm 56 pressure on the fluid contained within sub-compartment 
58. As illustrated, diaphragm 85 is interconnected with the rod 96 and 
spring 98. As a result when the pressure inducing means 94 holds diaphragm 
56 in pressure inducing relation with the fluid in sub-compartment 58, the 
air in sub-compartment 60 and sub-compartment 86 is at atmospheric 
pressure and the air in sub-compartment 88 will be less than atmospheric 
pressure due to the negative back pressure induced in the manifold. As the 
negative back pressure in the manifold varies, diaphragm 85 affects the 
positioning of spring 98 and connecting rod 96. Accordingly the diaphragm 
56 will move. Thus, as the negative back pressure in manifold 14 changes, 
it has an effect on the atmospheric pressure within sub-compartment 88 
which causes the pressure inducing means 94 to adjust the amount of 
pressure induced on fluid contained within sub-compartment 58. 
As shown in FIGS. 1 through 4 the air relief valve 40 is connected 
electrically with switch 48 via conductors 104 and 106. Also, the 
auxiliary housing 42 includes a magnetizing means or solenoid coil shown 
generally at 108. Solenoid coil 108 when energized has an effect on 
connecting rod 96. Connecting rod 96 comprises a non-magnetic portion 96B 
and a magnetic portion 96A threaded together as shown at 110. The 
electrical connections of solenoid 108 are interconnected with switch 
means 48 via electrical lines 112 and 114. Lines 116 and 118 interconnect 
the D.C. voltange bus with the switch control means 48 on line 118. 
The operation of pump 18 with respect to the water injection system is 
briefly described. During normal operation, the valve operates 
substantially as shown in FIG. 2. That is to say diaphragm 56 pressurizes 
the fluid in sub-compartment 58 due to the force of spring 98 minus any 
forces due to the effect of the negative back pressure in manifold 14. As 
the negative back pressure in manifold 14 varies, diaphragm 85 adjusts the 
position of diaphragm 56 via connecting rod 96, thereby varying the 
pressure of the fluid contained in sub-compartment 58. Pressurization of 
fluid in sub-compartment 58 results in the fluid moving into chamber 72 
and out through outlet port 20 to the carburetor 16 of engine 14. As the 
amount of fluid in sub-compartment 58 decreases, the variable pressure 
inducing means 94 moves into the position substantially as shown in FIG. 
3. In this position a lower push bar 120 causes contacts 122 to close. 
This activates switching means 48 which in turn energizes the air valve 40 
and vacuum assist solenoid 108. Energization of air relief valve 40 causes 
valve 78 to move into the position substantially as shown in FIG. 4. This 
results in the atmospheric pressure of air contained within 
sub-compartment 60 and sub-compartment 86 to drop to that of the negative 
back pressure in the manifold 14. The negative back pressure within 
sub-compartment 60 tends to draw diaphragm 56 downward thereby drawing 
additional fluid from the water reservoir 32 via piping 30 and in through 
inlet port 68 into sub-compartment 58. To assist in moving diaphragm 56 
downward into pressure drawing relation, the solenoid 108 is energized and 
pulls the magnetic portion 96B of connecting rod 96 downwardly. The 
connecting rod 96 is pulled downwardly until such time as the actuating or 
pusher bar 124 brings contacts 126 into contact as shown in FIG. 4. As 
illustrated, pusher bar 124 is provided with a sleeve 123 that surrounds 
connecting rod 96. Also, pusher bar 124 has an adjusting screw 125 that 
allows the location of pusher bar 124 on the rod 96 to be changed. Thus, 
the location of the pusher bar 124 can be changed to vary the length of 
time of the water intake cycle. Fluid continues to leave the pump 18 via 
inlet 20 during the water intake cycle of the pump because of one-way 
valve 70 closing and because water in chamber 72 is under pressure due to 
the air pocket 74. When the contacts 126 are closed as shown in FIG. 4, 
the switch means 48 de-activates the valve 78 in relief air valve 40 so 
that the valve 78 moves back into the position shown substantially as in 
FIG. 2. This will bring the air pressure in the sub-compartment 60 and 86 
back up to atmospheric pressure. Also when contacts 126 are closed, switch 
means 48 de-activates solenoid 108. Diaphragm 56 is once again free to 
move into pressure inducing relation with the fluid contained in 
sub-compartment 58. 
Referring to FIGS. 5 and 6 the pressure sensitive nozzle 26 having the 
regulated orifice is described. The nozzle includes an auxiliary air flow 
path shown by arrows 130 and a primary air flow path shown by arrows 132. 
The nozzle includes a pressure sensitive means or piston 134 movable 
within cylinder 136. The auxiliary air flow path 130 is provided by 
cutting a notch out of the interior wall of cylinder 136. The auxiliary 
air flow channel 130 increases in size as it extends away from the inlet 
138 of nozzle 26 towards the regulated orifice 128. A spring means in the 
form of coiled spring 140 is mounted to a spring lock 142 positioned in 
the groove 144 of the nozzle 26. The other end of spring 140 surrounds the 
nose 146 of piston 134. When the pressure build up within the conical 
interior wall of piston 134 is below a predetermined amount, the spring 
140 pushes the piston 134 into the position substantially as shown in FIG. 
5. In this position, portion 148 of piston 134 blocks off the inlet of 
auxiliary flow path 130. As a result all fluid entering the inlet 138 of 
nozzle 26 passes through orifice 150 in the nose 146 of piston 134. As the 
pressure in the conical piston 134 builds up above a predetermined value, 
piston 134 moves towards the spring lock 142 and against spring 140. As a 
result an inlet is provided for the auxiliary fluid flow path 130. This 
latter position of the piston 134 is shown in FIG. 6. Because auxiliary 
fluid flow path 130 has an opening cross-section area that increases in 
size as the piston 134 moves towards the spring lock 142, the amount of 
fluid streaming out of nozzle 26 varies as the pressure of this fluid 
varies. It should be understood that because the piston 134 moves in 
response to a pressure build up within its conical walls, as the size of 
the inlet for auxiliary fluid path 130 increases, the buildup of fluid 
pressure within the cone of piston 134. Thus the position of the piston 
134 stabilizes when the fluid pressure stabilizes. 
In an alternative embodiment of the invention, the magnetizing means or 
solenoid 108 is used to maintain the diaphragm 56 of the pressure inducing 
means 94 in pressure inducing relation with the water contained in main 
sub-compartment 58. In this embodiment, the electrical conductors 116, 118 
of solenoid 108 would be connected to an electronic control circuit. The 
electronic control circuit would vary the energization of solenoid 108 as 
a function of change in the RPM of the engine. This would cause the 
pressure inducing means to vary the pressure of the water contained in 
sub-compartment 58. Of course the polarity of the connecting rod 96 would 
be changed. While this embodiment could be used during the normal 
operation of the engine, it preferably would be used for engines that have 
a lower negative back pressure developed in the intake manifold when 
operating at high RPM than at idling RPMs.