Patent US 4,136,389

This disclosure deals with a system for indicating to the driver of a vehicle the operating efficiency of a vehicle. The system senses the speed of the vehicle and a characteristic of the fuel supply system which is indicative of the fuel consumption. These two factors are combined in a dividing circuit which produces a signal indicating the fuel consumption rate which is a measure of the operating efficiency. This signal is fed to an indicator which displays the fuel consumption rate to the operator of the vehicle.