Recent development effort concentrated on further improvement of emission control and fuel economy. The Bosch electronic fuel injection was advanced from using absolute intake manifold pressure as main input variable to an air metering system. This approach simplifies emission control combined with less cost gained by other improvements.Better fuel economy in combination with low emissions is achieved by closed-loop control employing the λ-sensor. The structure of this control loop allows the application of a self-adaptive control system responding to changing operating conditions of the engine. A further possibility is the closed-loop control at air-fuel ratios slightly richer or leaner than stoichiometric. This application widens the use of the λ-sensor to different emission control packages dependent on applicable standards.