PURPOSE: To simplify construction by providing a control valve at a primary air intake passage and a turbocharger at a secondary air intake passage bypassing the primary passage, and gradually opening the control valve in a non- turbocharged range and closing said valve in a turbocharged range depending upon an increase in the opening of an accelerator.
CONSTITUTION: An air intake passage 1 is provided with a control valve 2 as common to a throttle valve and a control valve for turbocharging and an air intake passage 1A bypassing the control valve 2 is provided with a turbocharger 5. A control unit 4 controls the opening of the control valve 2 according to the opening of an accelerator, and intermittently controls an electro-magnetic clutch 7 connecting the turbocharger 5 to a crankshaft 6 depending upon an operation range. The control unit 4 gradually opens the control valve 2 in a non-turbocharged range, depending upon an increase in the opening of the accelerator. In a turbocharged range, said unit 4 gradually closes the control valve 2, depending upon an increase in the opening of the accelerator.
TATANI KAZUO
TSUJI KOJI
YATOMI SATOSHI
