The basic structure of a new engine control system for lean combustion is presented. A fuel atomizer is adopted to obtain a uniform mixture of fine fuel droplets, 40µm in diameter. A new air-fuel ratio sensor and an integrated control method for air flow are developed for precise and rapid response control of cylinder air-fuel ratios 8 to 26.
Great improvements in both fuel consumption and exhaust emission characteristics are obtained by increasing the mean air-fuel ratio to 25 under cruising condition. There are made possible by the stable combustion provided by the fine mixture.
This system provides the driver with quick vehicle response and good fuel economy, while ensuring smooth driveability.