| 摘要 |
661.390. Varying cylinder clearance. PETIT, G. Jan. 5, 1949 [Jan 28, 1948], No. 282/49. Class 7(ii) The compression ratio of a multi - cylinder engine is regulated by pistons 3 working in chambers 2 and connected to a crankshaft 6 enclosed with the pistons in a housing 4 containing oil under pressure for actuating the pistons. A hollow arm 23 connected to part of the crankshaft external of the housing has a valve, such as a spring- loaded ball 8, which controls the flow of oil from the housing via the crankshaft duct 7 and is operated automatically according to the variation of intake manifold pressure by means which may comprise a cam 12 moved about the crankshaft axis by a rod 16 connected to the spring-opposed diaphragm 19 of a gauge communicating with the manifold. In operation, with an increase in manifold pressure, the follower 11 is liberated during upward movement of the cam, and ball 8 under the action of spring 9 closes the arm opening 25 so that the oil pressure in the housing increases to move the pistons and decrease the compression chamber volume. The arm rises until the follower again engages the cam to open the valve, and oil escapes from the housing through conduits 14, 15 to the oil sump so that the pressure in the housing is decreased and the chamber volume increased. A pump 22 feeds the housing via a conduit 13.. In a modification, the cam has a lug acting on the ball and a shoulder to engage and accelerate the downward movement of the arm.
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