US 2016/0097333 A1Published application

Control of internal combustion engine with two-stage turbocharging

AssigneeGM Global Technology Operations LLC

InventorKo-Jen Wu

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Abstract

An internal combustion engine includes a cylinder block defining a cylinder, a cylinder head, an intake valve, an exhaust valve, and a variable exhaust valve timing mechanism. The engine also includes a turbocharging system configured to pressurize ambient airflow for delivery to the cylinder. The turbocharging system includes a low-flow turbocharger, a high-flow turbocharger, and a flow control device for selectively directing post-combustion gas to the low-flow and high-flow turbochargers. A controller directs the post-combustion gas to the low-flow turbocharger and selects a first predetermined exhaust valve timing when the engine operates below a predetermined speed and above a predetermined load. Alternatively, the controller directs the post-combustion gas to the high-flow turbocharger and selects a second predetermined exhaust valve timing at or above the predetermined engine speed. The first predetermined exhaust valve timing traps less post-combustion gas in the cylinder as compared to the second predetermined exhaust valve timing.

Claims20

Dependent claims

An internal combustion engine comprising:

a cylinder block defining a cylinder;
a cylinder head mounted to the cylinder block;
a reciprocating piston arranged inside the cylinder;
a crankshaft arranged in the cylinder block and rotated by the piston;
an intake valve operatively connected to the cylinder head and configured to control delivery of air to the cylinder for combustion therein;
an exhaust valve operatively connected to the cylinder head and configured to control removal of post-combustion gas from the cylinder;
a first mechanism configured to provide variable timing for the exhaust valve;
a turbocharging system configured to pressurize the air being received from the ambient for delivery to the cylinder, the turbocharging system including a low-flow turbocharger and a high-flow turbocharger each configured to be driven by the post-combustion gas, and a flow control device configured to selectively direct the post-combustion gas to the low-flow and high-flow turbochargers;
and
a controller configured to direct the post-combustion gas to the low-flow turbocharger via control of the flow control device and select a first predetermined timing for opening the exhaust valve via control of the first mechanism when the engine operates in a first mode below a predetermined speed and above a predetermined load, and direct the post-combustion gas to the high-flow turbocharger via control of the flow control device and select a second predetermined timing for opening the exhaust valve via control of the first mechanism when the engine operates in a second mode at or above the predetermined speed, wherein the first predetermined timing for opening the exhaust valve traps less post-combustion gas in the cylinder as compared to the second predetermined timing for opening the exhaust valve.

7 more elements

A method of controlling operation of an internal combustion engine having:

a cylinder block defining a cylinder;
a cylinder head mounted to the cylinder block;
a reciprocating piston arranged inside the cylinder;
a crankshaft arranged in the cylinder block and rotated by the piston;
an intake valve operatively connected to the cylinder head and configured to control delivery of air to the cylinder for combustion therein;
an exhaust valve operatively connected to the cylinder head and configured to control removal of post-combustion gas from the cylinder;
a first mechanism configured to provide variable timing for the exhaust valve;
and
a turbocharging system configured to pressurize the air being received from the ambient for delivery to the cylinder, the turbocharging system including a low-flow turbocharger and a high-flow turbocharger, each turbocharger configured to be driven by the post-combustion gas, and a flow control device configured to selectively direct the post-combustion gas to the low-flow and high-flow turbochargers;
the method comprising:
directing, by a controller configured to regulate operation of the engine, the post-combustion gas to the low-flow turbocharger via control of the flow control device and selecting a first predetermined timing for opening the exhaust valve via control of the first mechanism when the engine operates in a first mode below a predetermined speed and above a predetermined load;
and
directing by the controller the post-combustion gas to the high-flow turbocharger via control of the flow control device, and selecting via the controller a second predetermined timing for opening the exhaust valve via control of the first mechanism when the engine operates in a second mode at or above the predetermined speed;
wherein the first predetermined timing for opening the exhaust valve traps less post-combustion gas in the cylinder as compared to the second predetermined timing for opening the exhaust valve.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/508,123Filed 7 Oct 2014
Published: 7 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

F01L 1/047
By means of cams, camshafts, cam discs, eccentrics or the like: camshafts
F01L 1/344
Characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the…:…
F02B 37/007
Engines characterised by provision of pumps driven at least for part of the time by exhaust: with exhaust-driven pumps arranged in parallel , e.g.…
F02B 37/22
Control of the pumps: by varying cross-section of exhaust passages or air passages , e.g. by throttling turbine inlets or outlets or by varying…