Method and apparatus for rapidly changing the air-fuel ratio of an internal combustion engine from a lean condition to a rich condition

Claim 2

A regulator capable of use in regulating fuel pressure to a fuel-air mixer of gaseous fueled internal combustion engine between a lean and a rich mixture comprising: a. a body having a hollow interior; b. first separating means within the hollow interior for defining a first pressure chamber, the first separating means being positionally responsive to a pressure differential across it; c. gas inlet means into the first pressure chamber; d. valve means for the inlet means coupled to the first separating means so that the gas flow through the inlet means is a function of the position of the separating means: e. gas outlet means from the first pressure chamber; f. means for effecting a first predetermined pressure differential across the first separating means to effect a first predetermined pressure in the first pressure chamber; g. selectively actuatable means for effecting a second predetermined pressure differential across the first separating means to effect a second predetermined pressure in the first pressure chamber; h. second separating means within the hollow interior defining a second pressure chamber, the second separating means being positionally responsive to a pressure differential across it; i. means for effecting a pressure differential across the second separating means including means for communicating the second pressure chamber with a variable pressure source; j. the second separating means being operable upon the occurrence of a predetermined threshold pressure at the variable pressure source to be displaced to a coupling position from an uncoupled position and actuate the selectively actuatable means to effect the predetermined second pressure in the first pressure chamber; and k. means for preventing pressure communication between the second pressure chamber and the variable pressure source when the second separating means is in its coupling position until a predetermined return pressure at the variable pressure source exists.

Claim 3

The regulator claimed in claim 1 including bypass valve means for selectively communicating the second pressure chamber with the pressure source independently of the preventing means.

Claim 4

The regulator claimed in claim 1 wherein the preventing means includes a pilot valve having a valving element in pressure communication with the second pressure chamber and adapted for pressure communication with the variable pressure source, the pilot valve having biasing means for urging its valving element into a closed position where it terminates pressure communication between the variable pressure source and the second pressure chamber, the pilot valve being operative upon the presence of the return pressure therein to displace its valving element against the biasing means to an open position and establish pressure communication between the second pressure chamber and the variable pressure source to enable the return of the second separating means to its uncoupled position, and means is included coupled to the second separating means to maintain the valving element of the pilot valve in its open position when the second separating means is in its uncoupled position.

Claim 5

The regulator claimed in claim 3 wherein: selectively actuatable bypass valve means is included for selectively communicating the second pressure chamber with the variable pressure source independently of the preventing means, the bypass valve means being adapted for pressure communication with a reference pressure source and being in communication with the second pressure chamber, the bypass valve means having a valving element normally in position to communicate the reference pressure source with the second pressure chamber and to prevent pressure communication between the second pressure chamber and the variable pressure source, the valving element of the bypass valve upon actuation of the bypass valve being in a position to prevent pressure communication between the reference pressure source and second pressure chamber and to establish pressure communication between the second pressure chamber and the variable pressure source.

Claim 6

The regulator claimed in claim 4 wherein: means are provided to attenuate the pressure in the second pressure chamber relative to that of the variable pressure source.

Claim 7

The regulator claimed in claim 5 wherein: the attenuating means includes an orifice between the variable pressure source and the second pressure chamber and a second orifice between the reference pressure source and the second pressure chamber.

Claim 8

The regulator claimed in claim 6 wherein: means are provided to increase the effective area of the orifice between the variable pressure source and the second pressure chamber during the opening of the valving element of the pilot valve.

Claim 9

A regulator capable of use in regulating fuel pressure to a fuel-air mixer of gaseous fueled internal combustion engine between a lean and a rich mixture comprising: a. a body having a hollow interior; b. a first pressure responsive diaphragm within the hollow interior defining a first pressure chamber; c. a second pressure responsive diaphragm within the hollow interior defining a second pressure chamber, the first and second diaphragms being spaced apart to define a third pressure chamber; d. gas inlet means into the first pressure chamber; e. valve means for the inlet means coupled to the first diaphragm to meter gas flow through the inlet means as a function of the pressure response of the first diaphragm; f. gas outlet means from the first pressure chamber; g. means including the first and third pressure chambers for establishing a first predetermined pressure differential across the first diaphragm to effect a first predetermined pressure in the first pressure chamber; h. spring means urging the second diaphragm towards the first diaphragm; i. means including the spring means, the second pressure chamber and the third pressure chamber for effecting a pressure differential across the second diaphragm; j. means for communicating the second pressure chamber with a variable pressure source; k. the second diaphragm being operable upon the occurrence of a predetermined threshold pressure differential across it determined by a threshold pressure at the variable pressure source to be displaced from an uncoupled position to a coupling position wherein the spring means is coupled to the first diaphragm for effecting a second predetermined pressure differential across the first diaphragm; and l. a pilot valve disposed to control communication between the second pressure chamber and the variable pressure source, the pilot valve having a valving element in pressure communication with the second pressure chamber and adapted for pressure communication with the variable pressure source, and biasing means for urging the valving element into a closed position where it presents pressure communication between the variable pressure source and the second pressure chamber, the valving element being responsive to a predetermined return pressure of the variable pressure source to be displaced to an open position and establish pressurE communication between the second pressure chamber and the variable pressure source to enable the return of the second diaphragm to its uncoupled position, and means is included to maintain the valving element in its open position when the second diaphragm is in its uncoupled position.

Claim 10

A regulator capable of use in regulating fuel pressure to a fuel-air mixer of gaseous fueled internal combustion engine between a lean and a rich mixture comprising: a. a body having a hollow interior; b. a first pressure responsive diaphragm within the hollow interior defining a first pressure chamber; c. a second pressure responsive diaphragm within the hollow interior defining a second pressure chamber, the first and second diaphragms being spaced apart to define a third pressure chamber; d. gas inlet means into the first pressure chamber; e. valve means for the inlet means coupled to the first diaphragm to meter gas flow through the inlet means as a function of the pressure response of the first diaphragm; f. gas outlet means from the first pressure chamber; g. means including the first and third pressure chambers for establishing a first predetermined pressure differential across the first diaphragm to effect a first predetermined pressure in the first pressure chamber; h. spring means urging the second diaphragm towards the first diaphragm; i. means including the spring means, the second pressure chamber and the third pressure chamber for effecting a pressure differential across the second diaphragm; j. means for communicating the second pressure chamber with a variable pressure source; k. the second diaphragm being operable upon the occurrence of a predetermined threshold pressure differential across it determined by a threshold pressure at the variable pressure source to be displaced from an uncoupled position to a coupling position wherein the spring means is coupled to the first diaphragm for effecting a second predetermined pressure differential across the first diaphragm; and l. a pilot valve disposed to control communication between the second pressure chamber and the variable pressure source, the pilot valve having a valving element in pressure communication with the second pressure chamber and adapted for pressure communication with the variable pressure source, and biasing means for urging the valving element into a closed position where it presents pressure communication between the variable pressure source and the second pressure chamber, the valving element being responsive to a predetermined return pressure of the variable pressure source to be displaced to an open position and establish pressurE communication between the second pressure chamber and the variable pressure source to enable the return of the second diaphragm to its uncoupled position, and means is included to maintain the valving element in its open position when the second diaphragm is in its uncoupled position.

Claim 11

The regulator claimed in claim 8 wherein: selectively actuatable bypass valve means is included for selectively communicating the second pressure chamber with the variable pressure source independently of the preventing means, the bypass valve means being adapted for pressure communication with a reference pressure source and being in communication with the second pressure chamber, the bypass valve means having a valving element normally in position to communicate the reference pressure source with the second pressure chamber and to prevent pressure communication between the second pressure chamber and the variable pressure source, the valving element of the bypass valve upon actuation of the bypass valve being in a position to prevent pressure communication between the reference pressure source and second pressure chamber and to establish pressure communication between the second pressure chamber and the variable pressure source.

Claim 12

A regulator for use in regulating fuel pressure to a fuel-air mixer of a gaseous fueled internal combustion engine between a lean and a rich mixture comprising: a. a body having a hollow interior; b. means separating the hollow interior into a fuel chamber and a low pressure chamber, the separating means being displaceable between a first fuel-lean position and a second fuel-rich position; c. a fuel inlet into the fuel chamber adapted to be connected in the fuel system of the internal combustion engine; d. a fuel outlet from the fuel chamber adapted to be connected to the fuel-air mixer; e. a displaceable valve for the fuel inlet; f. means coupling the displaceable valve to the separating means to effect a predetermined low pressure and a predetermined high pressure in the fuel chamber when the separating means is in its first and its second position, respectively; g. port means for pressure communicating the low pressure chamber with the inlet manifold of the internal combustion engine; and h. biasing means for urging the separating means into its second position, the biasing means being operable upon the presence of a predetermined threshold intake manifold pressure in the low pressure chamber and the predetermined low pressure in the fuel chamber to be overcome by the resulting pressure differential such that the separating means is displaced to its second position in a step shift for effecting the predetermined high pressure in the fuel chamber.

Claim 13

A regulator for use in regulating fuel pressure to a fuel-air mixer of a gaseous fueled internal combustion engine between a lean and a rich mixture comprising: a. a body having a hollow interior; b. means separating the hollow interior into a fuel chamber and a low pressure chamber, the separating means being displaceable between a first fuel-lean position and a second fuel-rich position; c. a fuel inlet into the fuel chamber adapted to be connected in the fuel system of the internal combustion engine; d. a fuel outlet from the fuel chamber adapted to be connected to the fuel-air mixer; e. a displaceable valve for the fuel inlet; f. means coupling the displaceable valve to the separating means to effect a predetermined low pressure and a predetermined high pressure in the fuel chamber when the separating means is in its first and its second position, respectively; g. port means for pressure communicating the low pressure chamber with the inlet manifold of the internal combustion engine; and h. biasing means for urging the separating means into its second position, the biasing means being operable upon the presence of a predetermined threshold intake manifold pressure in the low pressure chamber and the predetermined low pressure in the fuel chamber to be overcome by the resulting pressure differential such that the separating means is displaced to its second position in a step shift for effecting the predetermined high pressure in the fuel chamber.

Claim 14

The regulator claimed in claim 10 wherein: a pilot valve controlling the port means is included, the pilot valve being adapted for pressure communication with intake manifold and being operative to prevent communication between the low pressure chamber and the inlet manifold when the separating means is in its second position and to reestablish such communication upon the sensing of a predetermined return intake manifold pressure lower than the threshold pressure.

Claim 15

The regulator claimed in claim 11 wherein: a bypass valve is included, the bypass valve having an inlet in pressure communication with the low pressure chamber, an outlet adapted for pressure communication with the intake manifold, and means operative by the starter circuit of the internal combustion engine to open the bypass valve to establish communication between its inlet and outlet during engine starting.

Claim 16

The regulator claimed in claim 11 wherein the separating means includes a diaphragm between the fuel and low pressure chambers, and means is provided to attenuate the pressure in the fuel chamber relative to the intake manifold pressure.

Claim 17

The regulator claimed in claim 13 including a two-position bypass valve, the bypass valve having an inlet in pressure Communication with the low pressure chamber, a first outlet adapted for pressure communication with the intake manifold, a second outlet adapted for pressure communication with a reference pressure source of essentially atmospheric pressure, and means operative by the starter circuit of the internal combustion engine to actuate the bypass valve to a first position establishing pressure communication between the inlet and the first outlet while preventing pressure communication between the second outlet and the inlet, the bypass valve in its second position preventing pressure communication between the inlet and first outlet and establishing pressure communication between the second outlet and the inlet, the attenuating means including an orifice in the second outlet.

Claim 18

The regulator claimed in claim 14 wherein the attenuating means includes a second orifice in fluid circuit with the port means and controlled by the pilot valve in the same manner as the port means.

Claim 19

The regulator claimed in claim 14 wherein the attenuating means includes a second orifice between the pilot valve and the port means, and means controlled by the separating means is included to decrease the effective area of the second orifice after the pilot valve senses the return pressure and the separating means is in its first position.

Claim 20

In combination with an internal combustion engine having a fuel-air mixer for mixing a gaseous fuel with air, the fuel-air mixer being in communication with the intake manifold of the engine to supply the engine with a fuel-air mixture, an improved regulator for use in regulating fuel pressure to the fuel-air mixer between a lean and a rich mixture, the regulator comprising: a. a body having a hollow interior; b. means separating the hollow interior into a fuel chamber and a low pressure chamber, the separating means being displaceable between a first fuel-lean position and a second fuel-rich position; c. a fuel inlet into the fuel chamber adapted to be connected in the fuel system of the internal combustion engine; d. a fuel outlet from the fuel chamber coupled to the fuel-air mixer for supplying fuel thereto; e. a displaceable valve for the fuel inlet; f. means coupling the displaceable valve to the separating means to effect a predetermined low pressure and a predetermined high pressure in the fuel chamber when the separating means is in its first and its second position, respectively; g. port means pressure communicating the low pressure chamber with the inlet manifold of the internal combustion engine; and h. biasing means for urging the separating means into its second position, the biasing means being operable upon the presence of a predetermined threshold intake manifold pressure in the low pressure chamber and the predetermined low pressure in the fuel chamber to be overcome by the resulting pressure differential such that the separating means is displaced in a step shift to its second position for effecting the predetermined high pressure in the fuel chamber.

Claim 21

In combination with an internal combustion engine having a fuel-air mixer for mixing a gaseous fuel with air, the fuel-air mixer being in communication with the intake manifold of the engine to supply the engine with a fuel-air mixture, an improved regulator for use in regulating fuel pressure to the fuel-air mixer between a lean and a rich mixture, the regulator comprising: a. a body having a hollow interior; b. means separating the hollow interior into a fuel chamber and a low pressure chamber, the separating means being displaceable between a first fuel-lean position and a second fuel-rich position; c. a fuel inlet into the fuel chamber adapted to be connected in the fuel system of the internal combustion engine; d. a fuel outlet from the fuel chamber coupled to the fuel-air mixer for supplying fuel thereto; e. a displaceable valve for the fuel inlet; f. means coupling the displaceable valve to the separating means to effect a predetermined low pressure and a predetermined high pressure in the fuel chamber when the separating means is in its first and its second position, respectively; g. port means pressure communicating the low pressure chamber with the inlet manifold of the internal combustion engine; and h. biasing means for urging the separating means into its second position, the biasing means being operable upon the presence of a predetermined threshold intake manifold pressure in the low pressure chamber and the predetermined low pressure in the fuel chamber to be overcome by the resulting pressure differential such that the separating means is displaced in a step shift to its second position for effecting the predetermined high pressure in the fuel chamber.

Claim 22

The regulator claimed in claim 17 wherein: a pilot valve controlling the port means is included, the pilot valve being adapted for pressure communication with the intake manifold and being operative to prevent communication between the low pressure chamber and the inlet manifold when the separating means is in its second position and to reestablish such communication upon the sensing of a predetermined return intake manifold pressure lower than the threshold pressure.

Claim 23

The regulator claimed in claim 18 wherein: a bypass valve is included, the bypass valve having an inlet in pressure communication with the intake manifold, and means operative by the starter circuit of the internal combustion engine to open the bypass valve to establish communication between its inlet and outlet during engine starting.

Claim 24

The regulator claimed in claim 18 wherein the separating means includes a diaphragm between the fuel and low pressure chambers, and mEans is provided to attenuate the pressure in the fuel chamber relative to the intake manifold pressure.

Claim 25

The regulator claimed in claim 20 including a two-position bypass valve, the bypass valve having an inlet in pressure communication with the low pressure chamber, a first outlet adapted for pressure communication with the intake manifold, a second outlet adapted for pressure communication with a reference pressure source of essentially atmospheric pressure, and means operative by the starter circuit of the internal combustion engine to actuate the bypass valve to a first position establishing pressure communication between the inlet and the first outlet while preventing pressure communication between the second outlet and the inlet, the bypass valve in its second position preventing pressure communication between the inlet and first outlet and establishing pressure communication between the second outlet and the inlet, the attenuating means including an orifice in the second outlet.

Claim 26

The regulator claimed in claim 21 wherein the attenuating means includes a second orifice between the pilot valve and the port means, and means controlled by the separating means is included to decrease the effective area of the second orifice after the pilot valve senses the return pressure, and the separating means is in its first position.

Claim 27

The regulator claimed in claim 17 wherein the predetermined low pressure corresponds to a fuel-air ratio of from between about 1.25 to about 1.35 on an equivalence basis and the predetermined high pressure corresponds to a fuel-air ratio of about 0.9.

Claim 30

The method claimed in claim 24 including the step of returning the regulated pressure in a step shift from the second pressure to the first pressure at an intake manifold pressure below that required to initiate operation at the second pressure.

Claim 31

The method claimed in claim 24 wherein the predetermined intake manifold pressure corresponding to at least nearly full throttle is about 29 inches of mercury, and the intake manifold pressure at which the regulated pressure drops from the second pressure to the first pressure is about 20 inches of mercury.

Claim 32

The method claimed in claim 26 wherein the fuel-air mixture at the first pressure is at an equivalence ratio of from between about 1.25 to about 1.35 and the fuel-air mixture at the second pressure is at an equivalence ratio slightly less than one.

Claim 33

The method claimed in claim 27 wherein the fuel-air mixture at the second pressure is at an equivalence ratio of about 0.9.

Claim 34

An improved regulator for use in regulating fuel presSure to a gaseous fuel, fuel-air mixer of an internal combustion engine comprising: a. means for regulating the pressure of a gaseous fuel to a first pressure corresponding to a fuel-lean condition leaner than the air-fuel ratio at which maximum NOx occurs during normal operating conditions of the engine over a range of operating conditions including a cruise condition to at least nearly a fully throttle condition; b. pressure increasing means responsive to intake manifold pressure for changing the regulated pressure of the gaseous fuel to a second pressure higher than the first pressure at an intake manifold pressure corresponding at least to about the full throttle operating conditions, the second pressure corresponding to a fuel-rich condition richer than the air-fuel ratio at which maximum NOx occurs; and c. return means responsive to intake manifold pressure for returning to the first pressure from the second pressure at an intake manifold pressure below that required to initiate operation at the second pressure.

Claim 35

An improved regulator for use in regulating fuel presSure to a gaseous fuel, fuel-air mixer of an internal combustion engine comprising: a. means for regulating the pressure of a gaseous fuel to a first pressure corresponding to a fuel-lean condition leaner than the air-fuel ratio at which maximum NOx occurs during normal operating conditions of the engine over a range of operating conditions including a cruise condition to at least nearly a fully throttle condition; b. pressure increasing means responsive to intake manifold pressure for changing the regulated pressure of the gaseous fuel to a second pressure higher than the first pressure at an intake manifold pressure corresponding at least to about the full throttle operating conditions, the second pressure corresponding to a fuel-rich condition richer than the air-fuel ratio at which maximum NOx occurs; and c. return means responsive to intake manifold pressure for returning to the first pressure from the second pressure at an intake manifold pressure below that required to initiate operation at the second pressure.

Claim 36

The improved regulator claimed in claim 29 wherein each of the pressure increasing means and the return means effects its change in pressure between the first pressure and the second pressure in step shift.

Claim 37

The improved regulator claimed in claim 30 including means for maintaining the first pressure during engine startup.