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A positive airway pressure assist breathing apparatus or ventilator system has a gas delivery unit, an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a, patient during an inspiratory phase of each breath, and an expiratory unit for controlli

A positive airway pressure assist breathing apparatus or ventilator system has a gas delivery unit, an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a, patient during an inspiratory phase of each breath, and an expiratory unit for controlling exhausting of gases from the patient during an expiratory phase of each breath. A pressure sensor senses gas pressure in the system, and a control unit controls pressure of gas supplied to a patient in each inspiratory phase based on a pre-set target pressure. The control unit is arranged to calculate a boost pressure level periodically according to a determined patient breathlessness level, and to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level higher than the pre-set target pressure, and to reduce the pressure back to the pre-set target pressure at a predetermined time after the start of the inspiratory phase and prior to the end of the inspiratory phase. Boost pressure is adjusted periodically based on each new determination of the patient breathlessness level.

대표청구항 ▼

A positive airway pressure assist breathing apparatus or ventilator system has a gas delivery unit, an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a, patient during an inspiratory phase of each breath, and an expiratory unit for controlli

A positive airway pressure assist breathing apparatus or ventilator system has a gas delivery unit, an inspiration line connected to the output of the gas delivery unit for connecting the gas delivery unit to a, patient during an inspiratory phase of each breath, and an expiratory unit for controlling exhausting of gases from the patient during an expiratory phase of each breath. A pressure sensor senses gas pressure in the system, and a control unit controls pressure of gas supplied to a patient in each inspiratory phase based on a pre-set target pressure. The control unit is arranged to calculate a boost pressure level periodically according to a determined patient breathlessness level, and to boost the pressure of gas supplied to the patient at the start of each inspiratory phase to the calculated boost pressure level higher than the pre-set target pressure, and to reduce the pressure back to the pre-set target pressure at a predetermined time after the start of the inspiratory phase and prior to the end of the inspiratory phase. Boost pressure is adjusted periodically based on each new determination of the patient breathlessness level. a signal processing circuit accepting signals from the phase set point input, cam phase input, and four-way drive input and outputting to the four-way drive output such that when a phase set point signal is applied at the phase set point input, the control circuit provides an electrical signal at the four-way valve output to modulate the control ports such that oil is ported through one of the control ports, which moves the spool to control the variable cam phaser to shift the phase of the camshaft as selected by the phase set point signal. 3. The variable cam timing system of claim 1, further comprising a position sensor (34) coupled to the spool, having a position signal output representing the physical position of the spool. 4. The variable timing system of claim 3, further comprising: i) a VCT control circuit comprising: a cam phase input coupled to the VCT phase measurement sensors; a phase set point input for accepting a signal representing a desired relative phase of the camshaft and crankshaft; a spool valve position input coupled to the position signal output; and a four-way valve drive output coupled to the electrical input of the four-way valve; a signal processing circuit accepting signals from the phase set point input, cam phase input, and spool valve position input and outputting to the four-way valve drive output such that when a phase set point signal is applied at the phase set point input, the control circuit provides an electrical signal at the four-way valve output to modulate the control ports such that oil is ported through one of the control ports, which moves the spool to control the variable cam phaser to shift the phase of the camshaft as selected by the phase set point signal. 5. The variable cam timing system of claim 4, in which the signal processing circuit comprises: an outer loop for controlling the phase angle, coupled to the set point input, cam phase input, and four-way valve drive output; and an inner loop for controlling the spool valve position, coupled to the spool valve position input and to the inner loop; such that the four-way valve drive output as set by the outer loop is modified by the inner loop based on the spool valve position. 6. The variable cam timing system of claim 5, in which: a) the outer loop comprises: i) an anti-windup loop comprising: A) a first PI controller (52) having a first input coupled to the set point input; a second input coupled to the cam phase input; a third input and an output; B) a phase compensator (53) having an input coupled to the output of the first PI controller and a first output and a second output; and C) anti-windup logic (54) having an input coupled to the second output of the phase compensator and an output coupled to the third input of the PI controller; ii) a combiner (71) having a first input coupled to a null position offset signal (65), a second input coupled to the output of the phase comparator, a third input, and an output; iii) a second PI controller (66) having an input coupled to the output of the combiner and an output; and iv) a current driver (72) having an input coupled to the output of the second PI controller and an output coupled to the four-way valve drive output; and b) the inner loop comprises coupling the spool valve position input to the third input of the combiner. 7. The variable cam timing system of claim 6, further comprising a dither signal (58) coupled to the four-way valve drive output. 8. The variable cam timing system of claim 3, wherein the position sensor is selected from the group consisting of a linear potentiometer, a hall effect sensor, and a tape end sensor. 9. The variable cam timing system of claim 3, wherein the spool and the position sensor are coupled by a means selected from the group consisting of a physical coupling, an optical coupling, a magnetic coupling, and a capacitive coupling. 10. The variable cam timing system of claim 1, wherein the oil from the c ontrol ports is fed through a center of the camshaft. 11. The variable cam timing system of claim 1, wherein the exhaust port comprises two exhaust ports. 12. A variable cam timing system for an internal combustion engine having a crankshaft, at least one camshaft, a cam drive connected to the crankshaft, and a variable cam phaser having an inner portion mounted to at least one camshaft and a concentric outer portion connected to the cam drive, the relative angular positions of the inner portion and the outer portion being controllable in response to a fluid control input, such that the relative phase of the crankshaft and at least one camshaft can be shifted by varying the fluid at the fluid control input of the variable cam phaser, the variable cam timing system comprising: a) a spool valve (28) comprising a spool slidably mounted in a bore at an axis at a center of the inner portion of the variable cam phaser, the bore having a plurality of passages coupled to the fluid control input of the variable cam phaser, such that axial movement of the spool in the bore controls fluid flow at the fluid control input of the variable cam phaser; b) a first solenoid valve (12) comprising: i) an electrical input, which controls a flow of pressure to a first end (26) of the spool; ii) a fluid pressure input; and iii) a control port (16) coupled to a first end (26) of the spool, wherein when the solenoid valve is actuated, the control port feeds engine oil pressure (32) to the first end of the spool; and c) a second solenoid valve (13) comprising: i) an electrical input, which controls a flow of pressure to the second end (27) of the spool; ii) a fluid pressure input; and iii) a control port (17) coupled to a second end (27) of the spool, wherein when the second solenoid valve is actuated, the control port feeds engine oil pressure (32) to the second end of the spool. 13. The variable cam timing system of claim 12, further comprising: i) VCT phase measurement sensors (61)(62) coupled to the crankshaft and the at least one camshaft controlled by the variable cam timing system; and ii) a VCT control circuit comprising: a cam phase input coupled to the VCT phase measurement sensors; a phase set point input for accepting a signal representing a desired relative phase of the camshaft and crankshaft; a combiner (56) comprising a first input coupled to a null duty cycle signal (55), a second input coupled to an output of a phase comparator, and an output; a current driver (57) having an input coupled to the output of the combiner, and an output; a first solenoid drive input coupled to the combiner output; a second solenoid drive input coupled to the combiner output; a first solenoid drive output coupled to the electrical input of the first solenoid valve; a second solenoid drive output coupled to the electrical input of the second solenoid valve; a signal processing circuit accepting signals from the phase set point input, cam phase input, first solenoid drive input, and second solenoid drive input and outputting to the first and second solenoid drive outputs such that when a phase set point signal is applied at the phase set point input, the control circuit provides an electrical signal at the first and second solenoid drive outputs to modulate the amount of oil being ported through the control ports and move the spool to control the variable cam phaser to shift the phase of the camshaft as selected by the phase set point signal. 14. The variable cam timing system of claim 12, further comprising a position sensor (34) coupled to the spool, having a position signal output representing the physical position of the spool. 15. The variable timing system of claim 14, further comprising: i) a VCT control circuit comprising: a cam phase input coupled to the VCT phase measurement sensors; a phase set point input for accepting a signal representing a desired relative phase of the camshaft and crankshaft; a spool v alve position input coupled to the position signal output; a first solenoid drive output coupled to the electrical input of the first solenoid valve; and a second solenoid drive output coupled to the electrical input of the second solenoid valve; a signal processing circuit accepting signals from the phase set point input, cam phase input, and spool valve position input and outputting to the first and second solenoid drive outputs such that when a phase set point signal is applied at the phase set point input, the control circuit provides an electrical signal at the first and second solenoid drive outputs to modulate the amount of oil being ported through the control ports and move the spool to control the variable cam phaser to shift the phase of the camshaft as selected by the phase set point signal. 16. The variable cam timing system of claim 15, in which the signal processing circuit comprises: an outer loop for controlling the phase angle, coupled to the set point input, cam phase input, and first and second solenoid drive outputs; and an inner loop for controlling the spool valve position, coupled to the spool valve position input and to the inner loop; such that the first and second solenoid drive outputs as set by the outer loop are modified by the inner loop based on the spool valve position. 17. The variable cam timing system of claim 16, in which: a) the outer loop comprises: i) an anti-windup loop comprising: A) a first PI controller (52) having a first input coupled to the set point input; a second input coupled to the cam phase input; a third input and an output; B) a phase compensator (53) having an input coupled to the output of the first PI controller and a first output and a second output; and C) anti-windup logic (54) having an input coupled to the second output of the phase compensator and an output coupled to the third input of the PI controller; ii) a combiner (71) having a first input coupled to a null position offset signal (65), a second input coupled to the output of the phase comparator, a third input, and an output; and iii) a second PI controller (66) having an input coupled to the output of the combiner and an output coupled to the first and second solenoid drive inputs; and b) the inner loop comprises coupling the spool valve position input to the third input of the combiner. 18. The variable cam timing system of claim 14, wherein the position sensor is selected from the group consisting of a linear potentiometer, a hall effect sensor, and a tape end sensor. 19. The variable cam timing system of claim 14, wherein the spool and the position sensor are coupled by a means selected from the group consisting of a physical coupling, an optical coupling, a magnetic coupling, and a capacitive coupling. 20. The variable cam timing system of claim 12, wherein the oil from the control ports is fed through a center of the camshaft. 21. An internal combustion engine, comprising: a) a crankshaft; b) at least one camshaft (33); c) a cam drive connected to the crankshaft; d) a variable cam phaser having an inner portion mounted to at least one camshaft and a concentric outer portion connected to the cam drive, the relative angular positions of the inner portion and the outer portion being controllable in response to a fluid control input, such that the relative phase of the crankshaft and at least one camshaft can be shifted by varying the fluid at the fluid control input of the variable cam phaser; and e) a variable cam timing system comprising: i) a spool valve (28) comprising a spool slidably mounted in a bore at an axis at a center of the inner portion of the variable cam phaser, the bore having a plurality of passages coupled to the fluid control input of the variable cam phaser, such that axial movement of the spool in the bore controls fluid flow at the fluid control input of the variable cam phaser; and ii) a four-way valve (2) comprising: A) an electrical input, which controls a flow of pressure to the spool; B) a fluid pressure input; C) a first control port (3) coupled to a first end (26) of the spool; D) a second control port (4), coupled to a second end (27) of the spool; and E) at least one exhaust port; wherein when the four-way valve is in a first position, the pressure input is connected to the first control port, and the exhaust port is connected to the second control port such that oil pressure is transferred to the first end of the spool; wherein when the four-way valve is in a second position, the pressure input is connected to the second control port, and the exhaust port is connected to the first control port such that oil pressure is transferred to the second end of the spool; and wherein a position of the four-way valve causes the spool to move axially in the bore. 22. The engine of claim 21, further comprising a position sensor (34) coupled to the spool, having a position signal output representing the physical position of the spool. 23. An internal combustion engine, comprising: a) a crankshaft; b) at least one camshaft (33); c) a cam drive connected to the crankshaft; d) a variable cam phaser having an inner portion mounted to at least one camshaft and a concentric outer portion connected to the cam drive, the relative angular positions of the inner portion and the outer portion being controllable in response to a fluid control input, such that the relative phase of the crankshaft and at least one camshaft can be shifted by varying the fluid at the fluid control input of the variable cam phaser; and e) a variable cam timing system comprising: i) a spool valve (28) comprising a spool slidably mounted in a bore at an axis at a center of the inner portion of the variable cam phaser, the bore having a plurality of passages coupled to the fluid control input of the variable cam phaser, such that axial movement of the spool in the bore controls fluid flow at the fluid control input of the variable cam phaser; ii) a first solenoid valve (12) comprising: A) an electrical input, which controls a flow of pressure to a first end (26) of the spool; B) a fluid pressure input; and C) a control port (16) coupled to a first end (26) of the spool, wherein when the solenoid valve is actuated, the control port feeds engine oil pressure (32) to the first end of the spool; and iii) a second solenoid valve (13) comprising: A) an electrical input, which controls a flow of pressure to the second end (27) of the spool; B) a fluid pressure input; and C) a control port (17) coupled to a second end (27) of the spool, wherein when the second solenoid valve is actuated, the control port feeds engine oil pressure (32) to the second end of the spool. 24. The engine of claim 23, further comprising a position sensor (34) coupled to the spool, having a position signal output representing the physical position of the spool. 25. In an internal combustion engine having a variable camshaft timing system for varying the phase angle of a camshaft relative to a crankshaft, a method of regulating the flow of fluid from a source to a means for transmitting rotary movement from the crankshaft to a housing, comprising the steps of: sensing the positions of the camshaft and the crankshaft; calculating a relative phase angle between the camshaft and the crankshaft, the calculating step using an engine control unit for processing information obtained from the sensing step, the engine control unit further adjusting a command signal based on a phase angle error; controlling a position of a vented spool slidably positioned within a spool valve body, the controlling step utilizing a four-way valve comprising an electrical input, which controls a flow of pressure to the spool, a fluid pressure input, a first control port coupled to a first end of the spool, a second control port, coupled to a second end of the spool, and at least one exhaust port, wherein when the four-way valv