this dial 1 is generally composed of approximately 20 horizontal bars 2 each representing a unit consumption of one liter of fuel per 100 kilometers traveled each bar 2 can be lighted by an electro optical device such as a liquid crystal display lcd or an led for example to show an instantaneous unit consumption of 7 liters 100 km the seven lower horizontal bars are lighted and the driver can learn at a glance what his instantaneous unit consumption is by comparing the height of the lighted area with the total height of the dial the corresponding unit consumption can also be shown on each bar fig1 shows a series of bars lighted from the base of the dial the number of lighted bars being for example 16 to represent an instantaneous unit consumption of 16 liters 100 km the driver cannot count the number of lighted bars but he can see by overall comparison that approximately 3 4 of the dial surface is lighted and that if unit consumption when the entire dial is lighted is 20 1 100 km his instantaneous consumption is close to 15 1 100 km at the same time the driver notes the portion of an unlighted bar 3 which represents in contrast the minimum theoretical unit consumption of the vehicle traveling at the same instantaneous speed but at a steady speed and over a level surface this theoretical unit consumption is 10 liters 100 km which the driver notes by the position of the bar 3 approximately in the center of the dial 1 the driver can also note the theoretical excess consumption as compared to the theoretical ideal by estimating the height 4 of the.