# US 2012/0073553 A1 · Exhaust valve timing for split-cycle engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0073553 A1 - Document ID: US20120073553A1 - Status: Published application - Kind: A1 - Application number: 13/247,811 - Filed: 2011-09-28 - Published: 2012-03-29 - Earliest claimed: 2010-09-29 - Assignees: Scuderi Group, LLC - Inventors: Ford Allen Phillips - Web page: https://patentgrep.com/patent/US20120073553A1 ## CPC - F02B 33/22: with pumping cylinder situated at side of working cylinder, e.g. the cylinders being parallel - F02B 21/00: Engines characterised by air-storage chambers - F02D 13/0276: {Actuation of an additional valve for a special application, e.g. for decompression, exhaust gas recirculation or cylinder scavenging} - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) ## Abstract The engines, engine components, and related methods disclosed herein generally involve closing an exhaust valve through which exhaust gasses and other combustion products are evacuated from the expansion cylinder of a split-cycle engine before opening a crossover expansion valve through which a fresh charge of air and/or fuel is supplied to the expansion cylinder. The exhaust valve is preferably closed as late as possible after a combustion event, but with sufficient margin before opening of the crossover expansion valve and, in the case of an inwardly-opening exhaust valve, before valve-to-piston contact occurs. Preferably, the exhaust valve is closed about 0 CA degrees to about 15 CA degrees before the crossover expansion valve is opened. ## Claims ### Claim 1 An engine comprising: a crankshaft rotatable about a crankshaft axis; a compression piston slidably received within a 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; an expansion piston slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft; a crossover passage interconnecting the compression and expansion cylinders, the crossover passage including at least a crossover expansion valve disposed therein; and an exhaust valve through which exhaust gasses can be evacuated from the expansion cylinder; wherein the crossover expansion valve is opened between about 0 CA degrees and about 15 CA degrees after the exhaust valve is closed. ### Claim 2 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is opened between about 3 CA degrees and about 10 CA degrees after the exhaust valve is closed. ### Claim 3 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is opened between about 3 CA degrees and about 5 CA degrees after the exhaust valve is closed. ### Claim 4 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is opened about 4 CA degrees after the exhaust valve is closed. ### Claim 5 (depends on 1) The engine of claim 1, wherein the crossover expansion valve controls fluid flow between the crossover passage and the expansion cylinder. ### Claim 6 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is outwardly-opening. ### Claim 7 (depends on 1) The engine of claim 1, wherein the exhaust valve is inwardly-opening. ### Claim 8 (depends on 1) The engine of claim 1, wherein the exhaust valve is closed before the expansion piston reaches its TDC position. ### Claim 9 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is opened before the expansion piston reaches its TDC position. ### Claim 10 (depends on 1) The engine of claim 1, wherein the crossover expansion valve is opened after the expansion piston reaches its TDC position. ### Claim 11 A method of operating a split-cycle engine comprising: opening an exhaust valve of the engine during an exhaust stroke such that exhaust gasses are evacuated from an expansion cylinder of the engine through the exhaust valve; closing the exhaust valve during the exhaust stroke and before an expansion piston disposed in the expansion cylinder reaches its TDC position; and opening a crossover expansion valve of the engine between about 0 CA degrees and about 15 CA degrees after closing the exhaust valve such that air flows from a crossover passage of the engine, through the crossover expansion valve, and into the expansion cylinder. ### Claim 12 (depends on 11) The method of claim 11, wherein the crossover expansion valve is opened between about 3 CA degrees and about 10 CA degrees after the exhaust valve is closed. ### Claim 13 (depends on 11) The method of claim 11, wherein the crossover expansion valve is opened between about 3 CA degrees and about 5 CA degrees after the exhaust valve is closed. ### Claim 14 (depends on 11) The method of claim 11, wherein the crossover expansion valve is opened about 4 CA degrees after the exhaust valve is closed. ### Claim 15 (depends on 11) The method of claim 11, wherein the crossover expansion valve is outwardly-opening. ### Claim 16 (depends on 11) The method of claim 11, wherein the exhaust valve is inwardly-opening. ### Claim 17 (depends on 11) The method of claim 11, wherein the crossover expansion valve is opened before the expansion piston reaches its TDC position. ### Claim 18 (depends on 11) The method of claim 11, wherein the crossover expansion valve is opened after the expansion piston reaches its TDC position.