Patent ID: 6820586
Filing Date: 2004-11-23
Classification: F02B

Abstract:
An engine comprising a connecting rod connected at one end to a piston through a piston pin, a first arm turnably connected at one end to the other end of said connecting rod and at the other end to a crankshaft through a crankpin, a second arm integrally connected at one end to the other end of said first arm, a control rod turnably connected at one end to the other end of said second arm, and a movable eccentric shaft mounted between eccentric positions of rotary shafts to which a power reduced at a reduction ratio 1/2 is transmitted from said crankshaft, said movable eccentric shaft being connected to the other end of said control rod, the stroke of said piston at an expansion stroke being larger than that at a compression stroke,wherein when various dimensions are represented as described below in an x-y plane constituted by an x-axis extending through an axis of said crankshaft along a cylinder axis and a y-axis extending through the axis of said crankshaft in a direction perpendicular to the x-axis: a length of said connecting rod is represented by L4; a length of said first arm is represented by L2; a length of said second arm is represented by L1; a length of said control rod is represented by L3; a length from the axis of said crankshaft to axes of said rotary shafts in a direction of the y-axis is represented by L5; a length from the axis of said crankshaft to the axes of said rotary shafts in a direction of the x-axis is represented by L6; an angle formed by said connecting rod with respective to the cylinder axis is represented by &phgr;4; an angle formed by said first and second arm is represented by &agr;; an angle formed by said second arm with the y-axis within the x-y plane is represented by &phgr;1; an angle formed by said control rod with the y-axis is represented by &phgr;3; an angle formed by a straight line connecting the axis of said crankshaft and said crankpin with the x-axis is represented by &thgr;; an angle formed by a straight line connecting the axes of said rotary shafts and the axis of said movable eccentric shaft with the x-axis is represented by &thgr;p; a value of the angle &thgr;p is represented by &ggr; when the angle &thgr; is â€œ0â€ ; a length between the axis of said crankshaft and said crankpin is represented by R; a length of the straight line connecting the axes of said rotary shafts and the axis of said movable eccentric shaft is represented by Rp; a rotational angular speed of said crankshaft is represented by &ohgr;; and a ratio of the rotational speed of said movable eccentric shaft to the rotational speed of said crankshaft is represented by &eegr; and the rotational direction thereof is represented by &eegr;=+0.5 or &eegr;=âˆ’0.5, the following equation is established: âˆ’L4Â·sin &phgr;4Â·d&phgr;4/dt+L2Â·cos (&agr;+&phgr;1)Â·d&phgr;1/dtâˆ’RÂ·&ohgr;Â·sin &thgr;=0 Wherein&phgr;4=arcsin {L2Â·cos (&agr;+&phgr;1)+RÂ·sin &thgr;âˆ’&dgr;}/L4d&phgr;4/dt=&ohgr;Â·[âˆ’L2Â·sin (&agr;+&phgr;1)Â·{RÂ·cos (&thgr;âˆ’&phgr;3)âˆ’&eegr;Â·RpÂ·cos (&thgr;pâˆ’&phgr;3)}/{L1Â·sin (&phgr;1+&phgr;3)}+RÂ·cos &thgr;}]/(L4Â·cos &phgr;4) &phgr;1=arcsin [(L32âˆ’L12âˆ’C2âˆ’D2)/(2Â·L1Â·(C2+D2)}]âˆ’arctan (C/D) &phgr;3=arcsin {(RÂ·cos &thgr;âˆ’L6âˆ’RpÂ·cos &thgr;p+L1Â·sin &phgr;1)/L3}C=L5+RpÂ·sin &thgr;pâˆ’RÂ·sin &thgr;D=L6+RpÂ·cos &thgr;pâˆ’RÂ·cos &thgr;&thgr;p=&eegr;Â·&thgr;+&ggr;d&phgr;1/dt=&ohgr;Â·{RÂ·cos (&thgr;âˆ’&phgr;3)âˆ’&eegr;Â·RpÂ·cos (&thgr;pâˆ’&phgr;3)}/(L1Â·sin (&phgr;1+&phgr;3)}and crank angles &thgr; at a top dead center at each of the intake and exhaust strokes and at the top dead center at the compression stroke are determined from said equation, and the length L1 of said second arm; the length L2 of said first arm; the length L3 of said control rod; the length L4 of said connecting rod; the length L5 from the axis of said crankshaft to the axes of said rotary shafts in the direction of the y-axis; the length L6 from the axis of said crankshaft to the axes of said rotary shafts in the direction of the x-axis; the amount &dgr; of offsetting of the cylinder axis from the axis of said crankshaft in the direction of the y-axis; the angle a formed by said first and second arms; the length R between the axis of said crankshaft and said crankpin; the length Rp of the straight line connecting the axes of said rotary shafts and the axis of said movable eccentric shaft and the angle &thgr;p when the angle &thgr; is â€œ0â€ , are determined so that the top dead center at each of the intake and exhaust strokes and the top dead center at the compression stroke are congruous with each other, according to the following equation:X=L4Â·cos &phgr;4+L2Â·sin (&agr;+&phgr;1)+RÂ·cos &thgr;which represents a level X of the piston pin at both said crank angles &thgr;.