By-Pass Air Control System

An air passage by-passing throttle valve is provided to route air directly into lower course of throttle valve. The air control valve is located in middle of this air passage and controls amount of air at engine starting, idle speed, etc.

The air control valve is driven by signals from SPFI control unit and regulates opening of by-pass to maintain idle speed at set value. Using air control valve, the system can provide the following functions: improved warm-up performance, compensation of idle speed according to altitude, compensation of idle speed with air conditioner in operation, and compensation for idle speed fluctuation with vehicle aging.