Split-cycle engine with disc valve

Abstract

A split-cycle engine with disc valve includes a crankshaft, a power cylinder and a compression cylinder. A gas crossover passage interconnects the compression cylinder and the power cylinder. An air intake port circumscribes a periphery of the compression cylinder and defines an outer valve seat. An annular ring having a generally central opening is disposed between the compression cylinder and the air intake port and forms a washer valve for opening and closing the air intake port. A disc valve member is concentrically mounted over the central opening of the annular ring. The disc valve member includes a piston portion having a sidewall biased into engagement with the outer valve seat for controlling flow between the compression cylinder and the gas crossover passage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of a valve assembly in accordance with the present invention for a split-cycle engine illustrating a washer valve of the assembly in an open position, a disc valve of the assembly in a closed position, and an unloading valve of the assembly in a closed position;

FIG. 2 is a schematic view of the valve assembly of FIG. 1 illustrating the washer valve in a closed position, the disc valve in an open position, and the unloading valve in a closed position;

FIG. 3 is a schematic view of the valve assembly of FIG. 1 illustrating the washer valve in a closed position, the disc valve in a closed position, and the unloading valve in an open position;

FIG. 4 is a disc valve concept of the Disc Valve Study illustrating the exhaust to crossover passage process;

FIG. 5 is a GT-Power Check Valve Characterization graph of discharge coefficient vs. AP of the Disc Valve Study;

FIG. 6 is a disc valve concept applied to a Split-Cycle Engine of the Disc Valve Study;

FIG. 7 is a graph of ITE vs. Piston-Head clearances for varying disc valve inlet maximum ΔP at 2400 rpm of the Disc Valve Study;

FIG. 8 is a graph of IMEP vs. Piston-Head Clearance for varying disc valve inlet maximum ΔP at 2400 rpm of the Disc Valve Study;

FIG. 9 is a graph of ITE of the Disc Valve Engine (having 0.1 mm P-H Clearance and 0.2 bar maximum disc valve inlet ΔP) vs. Non-Disc Split-Cycle Engine and Conventional Engine of the Disc Valve Study; and

FIG. 10 is a graph of IMEP of the Disc Valve Engine (having 0.1 mm P-H Clearance and 0.2 bar maximum disc valve inlet ΔP) vs. Non-Disc Split-Cycle Engine and Conventional Engine of the Disc Valve Study.

Claims

1. A disc valve assembly for a split-cycle engine, the disc valve assembly comprising: a generally circular air inlet having a central axis;an axially flexible washer-shaped annular ring having a generally central opening, the annular ring being adjacent said air inlet and forming a washer valve for opening and closing said air inlet;a generally circular outer valve seat adjacent said air inlet;a housing including a sleeve having an open end, a flow channel through said sleeve, and a control chamber;a disc valve member including a stem portion received in said sleeve through said sleeve open end and a piston portion connected to the stem portion, the piston portion having a sloped outer sidewall biased into engagement with said outer valve seat and a generally central opening defined by a sloped inner sidewall that forms an inner valve seat concentric with the central opening in said washer valve; andan unloading valve member disposed in said housing, the unloading valve member including a piston disposed in said control chamber, a stem extending from the piston through said control chamber and into said flow channel, and a disc-shaped valve portion connected to the stem opposite the piston, the disc-shaped valve portion having a sloped outer surface cooperable with said inner valve seat;said unloading valve member being biased into engagement with said inner valve seat.

2. The disc valve assembly of claim 1, wherein the piston of said unloading valve member is slidable within said control chamber and divides said control chamber into a biased portion and an unbiased portion.

3. The disc valve assembly of claim 2, further including a controller in communication with said biased portion and said unbiased portion of said control chamber, wherein the controller controls the pressure in said biased portion and said unbiased portion, thereby selectively seating and unseating said unloading valve member.

4. The disc valve assembly of claim 1, including a resilient member in said biased portion of said control chamber engaging the piston of said unloading valve member to bias said unloading valve member into engagement with said inner valve seat.

5. The disc valve assembly of claim 1, including a resilient member biasing said disc valve member into engagement with said outer valve seat.

6. The disc valve assembly of claim 5, wherein said resilient member surrounds the sleeve of said housing.

7. The disc valve assembly of claim 1, including a seal ring between the stem portion of said disc valve member and said sleeve.

8. The disc valve assembly of claim 1, wherein the sleeve and the stem portion of said disc valve member are concentric cylinders.

9. A split-cycle engine comprising: a crankshaft rotatable about a crankshaft axis;a cylinder bank including a power cylinder and a compression cylinder;a power piston slidably received within the power cylinder and operatively connected to the crankshaft such that the power piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft;a compression piston slidably received within the compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft;a gas crossover passage interconnecting the compression cylinder and the power cylinder;an air intake port having an open end circumscribing a periphery of the compression cylinder and an outer surface adjacent the open end that defines an outer valve seat;an annular ring having a generally central opening, the annular ring being disposed between the compression cylinder and the air intake port adjacent the open end of the air intake port forming a washer valve for opening and closing the air intake port; anda disc valve member concentrically mounted over the central opening of the annular ring, the disc valve member including a piston portion having a sidewall biased into engagement with the outer valve seat for controlling flow between the compression cylinder and the gas crossover passage;whereby during the intake stroke of the compression piston, the washer valve opens to allow intake air to be drawn into the compression cylinder, and during the compression stroke, the washer valve closes and the disc valve member opens to allow compressed intake air to enter the gas crossover passage from the compression cylinder.

10. The split-cycle engine of claim 9, wherein said annular ring includes peripheral tabs for mounting said annular ring to the cylinder bank.

11. The split-cycle engine of claim 9, further comprising a valve housing including a sleeve having an open end, the valve housing being disposed in the gas crossover passage; wherein said disc valve member is received in said sleeve through said sleeve open end.

12. The split-cycle engine of claim 11, including a resilient member surrounding the sleeve of said valve housing and biasing said disc valve member into engagement with said outer valve seat.

13. The split-cycle engine of claim 11, including a seal ring between said disc valve member and said sleeve.

14. The split-cycle engine of claim 11, wherein the sleeve and a stem portion of said disc valve member are concentric cylinders.

15. The split-cycle engine of claim 11, wherein: the piston portion of said disc valve member has a generally central opening defined by a sloped inner sidewall that forms an inner valve seat concentric with the central opening in said washer valve;the valve housing includes a flow channel through said sleeve and a control chamber; andan unloading valve member is disposed in said valve housing, the unloading valve member including a piston disposed in said control chamber, a stem extending from the piston through said control chamber and into said flow channel, and a disc-shaped valve portion connected to the stem opposite the piston, the disc-shaped valve portion having a sloped outer surface cooperable with said inner valve seat;wherein said unloading valve member is biased into engagement with said inner valve seat.

16. The split-cycle engine of claim 15, wherein the piston of said unloading valve member is slidable within said control chamber and divides said control chamber into a biased portion and an unbiased portion.

17. The split-cycle engine of claim 16, further including a controller in communication with said biased portion and said unbiased portion of said control chamber, wherein the controller controls the pressure in said biased portion and said unbiased portion, thereby selectively seating and unseating said unloading valve member.

18. The split-cycle engine of claim 15, including a resilient member in said biased portion of said control chamber engaging the piston of said unloading valve member to bias said unloading valve member into engagement with said inner valve seat.

19. The split-cycle engine of claim 15, wherein the flow channel in said valve housing is in communication with the air intake port; whereby opening of said unloading valve member allows compressed air in said compression cylinder to enter said flow channel and pass to said air intake port.