| 摘要 |
PURPOSE:To prevent leakage of fuel into an inoperative chamber at the time of acceleration, by forming connecting passages in a piston of a carburetor having a piston type acceleration pump in the manner that said passages communicate an operation chamber with a recess formed in said piston whereto the extention of the peripheral portion of a sealing member is located. CONSTITUTION:A circumferential recess 32 is formed in a piston 19 of an acceleration pump 16 at the portion thereof located on the side of an inoperative chamber, and the outer surface of the piston 19 at the portion is covered with a sealing member 33 the extention of the peripheral portion of which is located at the recess 32. The piston 19 is formed with connecting passages 37 which extend between the recess 32 and a spring seat 40 disposed on the side of an operation chamber 28 of the piston 19. With such an arrangement, when a throttle valve is operated for acceleration, pressurized fuel is delivered into the recess 32 via the connecting passages 37 formed in the piston 37 and forces the seal member 33 onto the surface of the cylinder wall. Since the clearance between the seal member 33 and a cylinder 18 is removed by the function of dynamic pressure of fuel acted effectively in the recess 32, it is enabled to prevent leakage of fuel into the work chamber 28 in a reliable manner. |
