| 摘要 |
<p>PURPOSE:To improve an operation property of an engine over a wide operation range by providing a means for variably adjusting closing timing of an air intake valve while adjusting opening timing to a smaller value that the change of the closing timing and a means for changing the length of an air intake passage in responce to changeover of operation of the air intake valve. CONSTITUTION:A bypass passage 8 is connected in parallel to an air intake passage 3 for each cylinder on the way of the passage, and flow passage changeover valves 9, 10 as means for changing the length of the air intake passage are provided at connecting parts of the bypass passage 8 to the air intake passage 3. In addition, in a dynamic valve mechanism, an air intake valve operating cam for opening and closing an air intake valve 18 for each cylinder is constructed by high and low speed cams 24A, 24B, and locker arm 26 is selectively engaged with the above-described cams 24A, 24B by operation of an actuation 31 via a holder 28. For example, in a low speed rotation region, the locker arm 26 is engaged with the low speed cam 24B, while the flow passage changeover valves 9, 10 are changed over to illusrated positions to lengthen the length of the air intake passage, enabling a prescribed engine output and fuel cost performance to be obtained.</p> |
