AIR FLOWRATE CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PURPOSE:To restrain the effect of negative pressure and irregular behavior of flowrate characteristics in a device having a throttle valve divided into two valves against the effect of pressure within the device by expanding the sectional area of an air flow passage connecting the upstream sides of each valve, and maintaining equal pressure at the upstream sides of each valve. CONSTITUTION:An electromagnetic drive device 1 generates a force for moving a valve 2 in a right direction via the supply of electric power. The valve 2 stops at the position where the driving force of the device 1 balances a force working in the reverse direction of a spring 3, and an air flowrate is controlled with the motion of the valve 2. The valve 2 is integrated with a left side valve A21 and a right side valve B22 via a spindle, and each pressure thereof generates forces in directions opposite to each other, thereby offsetting the forces. In this case, an air flow passage 4 connecting the upstream sides of the valves A21 and B22 to each other is made to have a sufficiently large sectional area. According to the aforesaid construction, even when an air flowrate is large, pressure at each upstream side of the valves A21 and B22 is made equal and the effect of the pressure is thereby restrained.