| 摘要 |
PURPOSE:To reduce mechanical resistance due to lube oil on a roller contact surface by providing a heating means for making the temperature of lube oil to lubricate the roller contact surface between a cam shaft and a tappet member, higher than the temperature of lube oil for lubricating other parts at a low lube oil temperature condition. CONSTITUTION:There are a lube oil passage 30 for feeding lube oil to a crank shaft 29 in a cylinder block, another lube oil passage 32 for feeding lube oil to the bearing part 31 of a cam shaft 2 and another lube oil passage 34 for feeding lube oil to a tappet system 33 in a warmed-up condition, respectively as oil passages for lube oil supplied from an oil pan 27 via an oil pump 28 and as related to each other in parallel. The lube oil passage 34 is provided with a changeover valve 36 whose open port position can be changed depending upon an oil temperature detecting means 35 in the oil pan 27. When the temperature of lube oil is low, a valve system 33 is fed with heated lube oil via a lube oil heating passage 23 running around an exhaust passage.
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