Method and apparatus to reduce engine combustion noise utilizing unit valve actuation

An apparatus adapted for use with an engine, the engine including a plurality of combustion chambers, an intake port, an exhaust port, and a piston being reciprocally movable in each of the combustion chambers between a top dead center position and a bottom dead center position forming an intake stroke during which air is introduced from the intake port into the combustion chamber, movable between the bottom dead center position and the top dead center position forming a compression stroke during which the air in the combustion chamber is compressed to an established temperature range and fuel is introduced at or before top dead center during which a desired ignition delay period occurs prior to combustion, and movable between the bottom dead center position and the top dead center position forming an exhaust stroke during which exhaust gas is expelled from the combustion chamber into the exhaust port, the apparatus comprising:

• flow control means including an intake valve operatively mounted in each one of the intake ports to selectively pass intake air into the combustion chambers during the intake stroke, and an exhaust valve operatively mounted in each one of the exhaust ports to selectively pass exhaust gas away from the combustion chambers during the exhaust stroke;
• means for actuating each of the intake valve and the exhaust valve independently in response to a control signal;
• and
• electronic control means responsive to sensed operating parameters to allow a controlled volume of exhaust gas therefrom to enter any preselected combustion chamber during its intake stroke following initiation of its intake stroke and terminating prior to completion of its intake stroke to elevate the temperature of the compressed air in the preselected combustion chamber.

An apparatus adapted for use with an engine, the engine including a plurality of combustion chambers, an intake port, an exhaust port, and a piston being reciprocally movable in each of the combustion chambers between a top dead center position and a bottom dead center position forming an intake stroke during which air is introduced from the intake port into the combustion chamber, movable between the bottom dead center position and the top dead center position forming a compression stroke during which the air in the combustion chamber is compressed to an established temperature range and fuel is introduced at or before top dead center during which a desired ignition delay period occurs prior to combustion, and movable between the bottom dead center position and the top dead center position forming an exhaust stroke during which exhaust gas is expelled from the combustion chamber into the exhaust port, the apparatus comprising:

• an intake valve operatively mounted in each intake port to selectively pass intake air into the combustion chambers during the intake stroke, and an exhaust valve operatively mounted in each exhaust port to selectively pass exhaust gas away from the combustion chambers during the exhaust stroke;
• means including a piezoelectric motor for actuating each of the intake valves and the exhaust valves independently in response to a control signal;
• and
• electronic control means for introducing a controlled volume of exhaust gas to any preselected combustion chambers during its intake stroke following initiation of the intake stroke and terminating prior to completion of the intake stroke so that at the start of the compression stroke the temperature of the compressed air in the combustion chamber is elevated reducing the ignition delay period, the electronic control means acts in response to sensed operating parameters.

A method of operating an engine having a plurality of combustion chambers, an intake port, an exhaust port, and a piston being reciprocally movable in each of the combustion chambers between a top dead center position and a bottom dead center position forming an intake stroke during which air is introduced from the intake port into the combustion chamber, movable between the bottom dead center position and the top dead center position forming a compression stroke during which the air in the cylinder is compressed to a preestablished temperature and fuel is introduced at or before top dead center during which a preestablished ignition delay period occurs prior to combustion, and movable between the bottom dead center position and the top dead center position forming an exhaust stroke during which exhaust gas is expelled from the combustion chamber into the exhaust port, comprising the steps of:

• (a) passing intake air into the combustion chambers during the intake stroke;
• (b) passing exhaust gas away from the combustion chambers during the exhaust stroke;
• (c) actuating each of the intake means and the exhaust means independently in response to a control signal;
• and
• (d) introducing a controlled volume of exhaust gas into any selected combustion chamber by initiation of the exhaust means for the selected combustion chamber during its intake stroke following initiation of the intake stroke and terminating prior to completion of the intake stroke effectively elevating the temperature of the air in the selected combustion chambers.