摘要:
A piston crank mechanism of an internal combustion engine includes an upper link connected to a piston, a lower link connected to both the upper link and a crankpin, and a control link through which the lower link is linked to an eccentric cam of a control shaft to restrict the degree of freedom of the lower link. By varying the angular position of the eccentric cam with respect to the control-shaft axis, the center of oscillating motion of the control link varies, thus varying a compression ratio. The center of gravity of the lower link, determined by an equivalent inertia weight obtained by adding weights of connecting pins and weights of the upper-link boss-shaped end and the control-link boss-shaped end connected to the lower link via the respective connecting pins to the lower-link self-weight, is situated closer to the center of the crankpin.
摘要:
A multi-link variable compression ratio engine is provided with a crankshaft (12), a piston (11), a control shaft (20), a linkage, a motor (35) and a reduction mechanism. The crankshaft (12) moves the piston (11) within an engine cylinder. The control shaft (20) has an eccentric axle eccentric relative to its center-axis. The linkage operatively connects the piston to the crankshaft and the crankshaft (12) to the eccentric axle of the control shaft (20). The motor (35) rotates the control shaft (20) so a top-dead-center position of the piston (11) changes to vary compression ratios by changing the positions of the eccentric axle and the linkage. The reduction mechanism (30) couples the motor (35) to the control shaft (20) to transmit a reduced rotation of the motor to the control shaft so a reduction ratio of a rotation angle of the motor to a rotation angle of the control shaft is less at high-compression ratios than at intermediate compression ratios.
摘要:
In a rockable-cam equipped reciprocating internal combustion engine, a rockable cam is rotatably fitted on the outer periphery of an intake-valve drive shaft that is rotatable in synchronism with rotation of a crankshaft. The rockable cam oscillates within predetermined limits during rotation of the intake-valve drive shaft so as to directly push an intake-valve lifter. As viewed from an axial direction of the crankshaft, an axis of the intake-valve drive shaft is offset from a centerline of the intake-valve stem in a first direction that is normal to both the cylinder centerline and the crankshaft axis and directed from the cylinder centerline to the intake valve side. The crankshaft axis is also offset from the cylinder centerline in the first direction.
摘要:
A combustion control system for a spark-ignition internal combustion engine includes a variable piston stroke characteristic mechanism changing a compression ratio of the engine, sensors detecting engine operating conditions, i.e., engine speed and engine load, and at least one of a variable lift and working angle control mechanism simultaneously continuously changing an intake-valve lift and an intake-valve working angle and a variable phase control mechanism changing an angular phase at a central angle corresponding to a maximum valve lift point of the intake valve. Also provided is a control unit that controls the variable piston stroke characteristic mechanism, and at least one of the variable lift and working angle control mechanism and the variable phase control mechanism, depending on the engine operating conditions.
摘要:
In an internal combustion engine, a variable lift and/or operating angle mechanism variably controls a lift and/or operating angle of an exhaust valve in accordance with a driving condition of the engine, a variable phase mechanism variably controls a phase of a lift center angle of the exhaust valve in accordance with the driving condition of the engine, a present position detecting section detects a present operating position of each of the variable lift and/or operating angle mechanism and variable phase mechanism, and a controlling section controls one of the variable lift and/or operating angle mechanism and the variable phase mechanism which operates normally in a direction in which an in-cylinder residual gas quantity becomes minimum when the other of the variable lift and/or operating angle mechanism and the variable phase mechanism has failed.
摘要:
In a variable compression ratio mechanism for an internal combustion engine employing an upper link, a lower link, and a control link, the lower link includes a crankpin bearing portion into which a crankpin is fitted, a first connecting-pin bearing portion into which a first connecting pin for the upper link is fitted, and a second connecting-pin bearing portion into which a second connecting pin for the control link is fitted. A central connecting portion is provided to connect an axial central portion of at least one of the first and second connecting-pin bearing portions to an axial central portion of the crankpin bearing portion. The central connecting portion has an axial length L1 shorter than each of an axial length L2 of the crankpin bearing portion, an axial length L3 of the first connecting-pin bearing portion, and an axial length L4 of the second connecting-pin bearing portion.
摘要:
A multi-link variable compression ratio engine is provided with a crankshaft (12), a piston (11), a control shaft (20), a linkage, a motor (35) and a reduction mechanism. The crankshaft (12) moves the piston (11) within an engine cylinder. The control shaft (20) has an eccentric axle eccentric relative to its center-axis. The linkage operatively connects the piston to the crankshaft and the crankshaft (12) to the eccentric axle of the control shaft (20). The motor (35) rotates the control shaft (20) so a top-dead-center position of the piston (11) changes to vary compression ratios by changing the positions of the eccentric axle and the linkage. The reduction mechanism (30) couples the motor (35) to the control shaft (20) to transmit a reduced rotation of the motor to the control shaft so a reduction ratio of a rotation angle of the motor to a rotation angle of the control shaft is less at high-compression ratios than at intermediate compression ratios.