Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Patent
1997-01-24
1998-07-14
Lo, Weilun
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
123 9031, F01L 1300
Patent
active
057788405
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a variable valve driving mechanism for controlling opening and closing of an intake valve and exhaust valve of an internal combustion engine at timings corresponding to a state of operation of the engine, and especially to a variable valve driving mechanism making use of a nonuniform speed coupling which can produce an output while retarding a rotational speed of input rotation.
2. Background Art
There are reciprocating valves drivenly opened and closed by a cam, for example, like an intake valve and exhaust valve (which may hereinafter be collectively called "engine valves") arranged in a reciprocating internal combustion engine (hereinafter referred to as an "engine"). Such valves are driven so that they are lifted in accordance with the profile and phase of rotation of a cam.. Accordingly, such timings of opening and closing of each valve and its open period (a quantity representing a period, in which the valve is maintained open, in terms of the unit of an angle of rotation of a crankshaft) also depend on the profile and phase of rotation of the cam.
In the case of an intake valve and exhaust valve arranged in an engine, the optimal timings of their opening and closing and their open periods vary in accordance with a state of loading on the engine and a state of its speed. A variety of mechanisms have therefore been proposed to make it possible to vary the timings of opening and closing of such valves and their open periods.
For example, mechanisms have been developed and put into practical use, which selectively use a cam having a cam profile for high speeds and a cam having a cam profile for low speeds so that valves are opened and closed selectively at valve opening and closing timings and for open periods suited to times of high speeds and to times of low speeds, respectively.
Further, techniques where a nonuniform speed coupling making use of an eccentric mechanism is interposed between a cam and a camshaft and that, while rotating the cam relative to the camshaft via the nonuniform speed coupling, the cam is caused to rotate at a speed different from the camshaft to permit adjusting the timings of opening and closing of valves and their open periods in accordance with a state of operation of an engine have been proposed, for example, in U.S. Pat. No. 3,633,555 referred to as "the first conventional art"! and G.B. Patent No. 2,268,570 hereinafter referred to as "the second conventional art"!.
For example, FIG. 16 and FIG. 17 disclose a variable valve timing camshaft mechanism according to U.S. Pat. No. 3,633,555 (the first conventional art) as published in SAE Technical Paper Series 880387. This mechanism is designed to permit changing of the valve timing by using a nonuniform speed coupling. In FIG. 22 and FIG. 23, designated by numerals 101 and 102 are a camshaft and a cam, respectively, and the cam 102 is arranged to be able to rotate concentrically with the camshaft 101 and relative to the camshaft 101. Between this camshaft 101 and this cam 102, a nonuniform speed coupling 103 is also interposed.
The nonuniform speed coupling 103 is provided with a collar 105 connected to the camshaft 101 via a locking screw 103 for integral rotation with the camshaft 101, an intermediate member 108 connected to the cam 102 via a drive pin 106 and slider 107 for integral rotation with the cam 102, and a drive pin 109 and slider 110 for transmitting rotation from the collar 105 to the intermediate member 108, and further with a rotation control sleeve 111 with the collar 105 and intermediate member 108 accommodated therein and a control shaft 112 for adjusting the phase of rotation of the rotation control sleeve 111.
The sliders 107,110 are accommodated slidably in a radial directions in elongated grooves 108A,108B of the intermediate member 108, respectively, so that rotation of the camshaft 101 is transmitted from the collar 105 of the nonuniform speed coupling 103 to the intermediate member 108 via the drive pin 109 and slider 110, and further to the
REFERENCES:
patent: 3633555 (1972-01-01), Raggi
patent: 5161493 (1992-11-01), Ma
patent: 5219313 (1993-06-01), Danieli
patent: 5333579 (1994-08-01), Hara et al.
patent: 5361736 (1994-11-01), Phoenix et al.
patent: 5365896 (1994-11-01), Hara et al.
patent: 5417186 (1995-05-01), Elrod et al.
F. Freudenstein, E.R. Maki, and Lung-Wen Tsai, The Synthesis and Analysis of Variable-Valve-Timing Mechanisms for Internal-Combustion Engines, pp. 1-10, International Congress and Exposition, Detroit, Michigan, Feb. 29-Mar. 4, 1988; SAE Technical Paper Series #880387, .COPYRGT.1988.
Hirano Takaaki
Isomoto Jun
Kubo Masahiko
Murata Shinichi
Lo Weilun
Mitsubishi Jidosha Engineering K.K.
Mitsubishi Jidosha Kogyo K.K.
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