Engine

Details Engine Engine

2003-03-19

2004-11-23

Kamen, Noah P. (Department: 3747)

Internal-combustion engines

Transmission mechanism from piston

C123S197400

Reexamination Certificate

active

06820586

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to 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 the 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 the first arm, a control rod turnably connected at one end to the other end of the second arm, and a movable eccentric shaft mounted between eccentric positions of rotary shafts to which a power reduced at a reduction ratio of 1/2 is transmitted from the crankshaft, the movable eccentric shaft being connected to the other end of the control rod, the stroke of the piston at an expansion stroke being larger than that at a compression stroke.
2. Description of the Related Art
Such engines are conventionally known, for example, from U.S. Pat. No. 4,517,931 and Japanese Patent Application Laid-open No. 9-228853. In each of these engines, the stroke of the piston at an expansion stroke is larger than that at a compression stroke, whereby a larger expansion work is carried out in the same amount of air-fuel mixture drawn, so that the cycle thermal efficiency is enhanced.
In the conventionally known engine, it is common that the position of a top dead center at each of the intake and exhaust strokes and the position of the top dead center at the compression stroke are different from each other. However, if the position of the top dead center at each of the intake and exhaust strokes is higher in level than the position of the top dead center at the compression stroke, there is a possibility that the interference of each of intake and exhaust valves and a top of the piston with each other occurs. If the position of the top dead center at each of the intake and exhaust strokes is lower in level than the position of the top dead center at the compression stroke to avoid the interference, the top dead center at the compression stroke is further lower and hence, an enhancement in a compression ratio in the engine is not desired and it is difficult to operate the engine at a higher thermal efficiency. On the other hand, if the top dead center at the compression stoke is higher in level than the top dead center at each of the intake and exhaust strokes, there is a possibility that the scavenge provided by the piston is insufficient due to the lower level of the piston at the top dead center at each of the intake and exhaust strokes, and thus, a large amount of burned gas remains within a cylinder, thereby bringing about a reduction in output in a full-load state and the instability of burning in a lower-load state.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an engine, wherein the stroke of the piston at the expansion stroke is larger than that at the compression stroke and in addition, the top dead center at each of the intake and exhaust stroke and the top dead center at the compression stroke are at the same level, whereby the above-described problems are solved.
To achieve the above object, according to a first feature of the present invention, there is provided 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 L
4
; a length of said first arm is represented by L
2
; a length of said second arm is represented by L
1
; a length of said control rod is represented by L
3
; a length from the axis of said crankshaft to axes of said rotary shafts in a direction of the y-axis is represented by L
5
; 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 L
6
; 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 a; 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 “0”; 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;=−0.5, the following equation is established:
L
4
·sin &phgr;
4
·
d
&phgr;
4
/
dt+L
2
·cos (&agr;+&phgr;
1
)·
d
&phgr;
1
/
dt−R
·&ohgr;·sin &thgr;=0
Wherein
&phgr;
4
=arcsin {L
2
·cos (&agr;+&phgr;
1
)+R·sin &thgr;−&dgr;}/L
4
d&phgr;
4
/dt=&ohgr;·[−L
2
·sin (&agr;+&phgr;
1
)·{R·cos (&thgr;−&phgr;
3
)−&eegr;·Rp·cos (&thgr;p−&phgr;
3
)}/{L
1
·sin (&phgr;
1
+&phgr;
3
)}+R·cos &thgr;)]/(L
4
·cos &phgr;
4
)
&phgr;
1
=arcsin [(L
3
2
−L
1
2
−C
2
−D
2
)/{2·L
1
·(C
2
+D
2
)}]−arctan(C/D)
&phgr;
3
=arcsin {(R·cos &thgr;−L
6
−Rp·cos &thgr;p+L
1
·sin &phgr;
1
)/L
3
}
C=L
5
+Rp·sin &thgr;p−R·sin &thgr;
D=L
6
+Rp·cos &thgr;p−R·cos &thgr;
&thgr;p=&eegr;·&thgr;+&ggr;
d&phgr;
1
/dt=&ohgr;·{R·cos (&thgr;−&phgr;
3
)−&eegr;Rp·cos (&thgr;p−&phgr;
3
)}/{L
1
·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 L
1
of said second arm; the length L
2
of said first arm; the length L
3
of said control rod; the length L
4
of said connecting rod; the length L
5
from the axis of said crankshaft to the axes of said rotary shafts in the direction of the y-axis; the length L
6
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 &agr; 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 “0”, are determined so that the top dead center at each of the intake and exhaust str

Affiliated with

Also associated with

Rating

Engine does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Engine will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3359055