<div class="htmlview paragraph">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.</div> <div class="htmlview paragraph">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.</div> <div class="htmlview paragraph">This system provides the driver with quick vehicle response and good fuel economy, while ensuring smooth driveability.</div>