摘要:
A variable compression-ratio, multiple-link type reciprocating internal combustion engine has at least three links, namely an upper link, a lower link and a third link, for each engine cylinder. The upper link is connected to a piston pin, the lower link connects the upper link to a crank pin, and the third link is pivoted at one end to a body of the engine and connected at its other end to either of the upper and lower links to permit oscillating motion of the third link on the engine body. The upper link, the lower link, and the third link are dimensioned and laid out, so that the amplitude of a second-order vibration component of a vibrating system of reciprocating motion of the piston, synchronizing rotary motion of the crankshaft, is suppressed and reduced to below a predetermined threshold value, while realizing the same piston stroke and engine-cylinder height as a single-link type reciprocating internal combustion engine in which a piston pin and a crank pin are connected to each other by a single link.
摘要:
A paired counterweights of a crankshaft have projected inner surfaces which protrude toward each other defining a given space therebetween. A plurality of links are arranged to convert a reciprocating motion of a piston to a rotational motion of the crankshaft. One of the links is pivotally connected to other links through link connecting portions and swingably disposed on a crank pin of the crankshaft so that upon rotation of the crankshaft, a peripheral portion of the link passes through the given space. At least one of the link connecting portions is placed within an imaginary circle which would be described by a radially innermost part of the projected inner surfaces of the paired counterweights when the paired counterweights turn about an axis of the crank pin.
摘要:
An internal combustion engine is constructed to include a variable compression ratio mechanism. The mechanism has the following structure. An upper link has one end pivotally connected to a piston pin of a piston of the engine. A lower link is pivotally disposed on a crank pin of a crankshaft of the engine and has one part pivotally connected to the other end of the upper link. A control shaft extends substantially in parallel with the crankshaft. A control link has an end pivotally connected to the other part of the lower link. The other end of the control link is connected to the control shaft through an eccentric bearing structure, so that rotation of the control shaft about its axis induces a pivoting of the lower link about the crank pin varying the stroke of the piston.
摘要:
In a piston actuation system of a V-type internal combustion engine with two cylinder banks having at least one pair of cylinders, a piston pin, an upper link, a lower link, and a control link are mechanically linked to each other for each cylinder bank. When changing a compression ratio of the engine, ends of the control links of the two cylinder banks are moved in synchronism. The lower links of the two cylinder banks are coaxially rotatably fitted on the outer periphery of the same crankpin whose axis is eccentric to the axis of the crankshaft.
摘要:
A variable compression ratio mechanism of a reciprocating engine includes at least an upper link connected at one end to a piston pin and a lower link connecting the other end of the upper link to a crankpin. At top dead center, when hypothetical connecting points between the upper and lower links are able to be supposed on both sides of the line segment connecting the piston-pin center and the crankpin center, and the first one of the connecting points has a smaller inclination angle, measured in the same direction as a direction of rotation of the crankshaft, from the axial line of reciprocating motion of the piston-pin center and to a line segment connecting the piston-pin center and the first connecting point; as compared to the second connecting point, the first connecting point is selected as the actual connecting point.
摘要:
A variable compression ratio mechanism for a reciprocating engine includes a connecting rod split into upper and lower connecting rod portions linked to each other through a first connecting pin. A rockable arm is oscillatingly linked at one end to the lower connecting rod portion through a second connecting pin. A control mechanism shifts the center of oscillating motion of the rockable arm to vary a compression ratio of the engine. A piston stroke is set to be greater than two times a crank radius of a crank, irrespective of variations in the compression ratio. A linkage is dimensioned and laid out, so that its crankpin load is less than a crankpin load produced by a linkage that the crankpin is located on a perpendicular line at substantially the midpoint of a line segment between and including the centers of the first and second connecting pins.
摘要:
A supercharged internal combustion engine is provided with a double-link type piston crank mechanism connecting between a piston and a crankshaft. The piston crank mechanism causes the piston to move at a speed which is smaller around a top dead center (TDC) and larger around a bottom dead center (BDC) as compared with respective corresponding piston speeds attained by a comparable single-link type piston crank mechanism. The double-link type piston crank mechanism variably controls a compression ratio by varying an angular position of one of links constituting the piston crank mechanism.
摘要:
In a reciprocating piston engine employing a variable compression ratio mechanism linked to a reciprocating piston for variably adjusting a geometrical compression ratio by varying at least a piston top dead center position, so that the top dead center position obtained at a low geometrical compression ratio is set to be lower than that at a high geometrical compression ratio, responsively to a controlled variable, a controller is configured to set a target compression ratio to a high value at low engine load operation, and to a relatively low value at high engine load operation. A substantially entire area of a crown of the piston, defining a part of a wall surface of a combustion chamber, is formed of a non-metallic material having a higher heat-insulating and heat-reserving property as compared to a base structural material of each of the combustion chamber and the piston.
摘要:
A piston crank mechanism has an upper link coupled to a piston by a piston pin, a lower link having a crankpin journal, wherein the crankpin journal is coupled to a crankpin of a crankshaft and is coupled to the upper link by an upper pin, and a control link is coupled to an eccentric cam of a control shaft that is supported by an engine block and coupled to a control pin boss by a control pin. The crankpin journal of the lower link is arranged and dimensioned relative to the upper pin such that a projection area defined by projecting the width of the upper pin along a direction line passing through a center of the piston pin and a center of the upper pin does not obscure an area defined by the crankpin during operation of the crankshaft as viewed in an axial direction of the crankpin.
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.