Abstract: A hydraulic variable compression ratio (VCR) piston for use in an internal combustion engine. The piston is a two-part piston, in which a gudgeon pin carrier slides within an outer sleeve. A variable volume upper chamber is formed between the top of the gudgeon pin carrier and the end of the outer sleeve. When the upper chamber fills with oil, its volume increases, and the overall piston geometry is longer. This reduces the piston clearance in the cylinder and increases cylinder pressure. At a given maximum cylinder pressure or at a given rate of increase of cylinder pressure, oil from the upper chamber is relieved by using a rate-sensitive pressure relief valve.

Abstract: A hydraulic variable compression ratio (VCR) piston for use in an internal combustion engine. The piston is a two-part piston, in which a gudgeon pin carrier slides within an outer sleeve. A variable volume upper chamber is formed between the top of the gudgeon pin carrier and the end of the outer sleeve. When the upper chamber fills with oil, its volume increases, and the overall piston geometry is longer. This reduces the piston clearance in the cylinder and increases cylinder pressure. At a given maximum cylinder pressure or at a given rate of increase of cylinder pressure, oil from the upper chamber is relieved by using a rate-sensitive pressure relief valve.

Abstract: A method for controlling the temperature and/or space velocity of exhaust gas provides control of the maximum temperature of the exhaust gas to prevent thermal damage to the Diesel engine components and associated aftertreatment devices during regeneration of the aftertreatment devices. The method includes controlling intake and/or exhaust valve opening timing and duration, either singly or in combination with selective individual cylinder cutout, in response to sensed engine operating parameters.