Fuel consumption signalling device for a motor vehicle

Claim 1

A signalling device for providing indications of the fuel consumption of an internal combustion engine of a motor vehicle, comprising: first sensor means for providing an electrical signal indicative of the rate of rotation of the vehicle engine; second sensor means for providing an electrical signal indicative of the speed of the vehicle; a first processing circuit connected to said first sensor means and arranged to provide a first information signal having an amplitude proportional to the rate of rotation of the engine; a second processing circuit connected to said second sensor means and arranged to provide a second information signal having an amplitude which is directly proportional to the speed of the vehicle when this speed is less than a predetermined value and a zero amplitude when the speed of the vehicle is greater than this predetermined value, said predetermined speed value being between the speed at which the fuel consumption is at a minimum under the slowest running conditions of the engine and the speed at which the fuel consumption is at a minimum under the fastest running conditions; a first adding circuit connected to said first and second processing circuits for providing a first sum signal corresponding to the sum of said first and second information signals according to respective first predetermined weighting factors, the amplitude of the first sum signal being indicative of the fuel consumption; first comparison circuit means arranged to compare the amplitude of said first sum signal with a plurality of predetermined ranges of values and to provide control signals indicative of the range of values within which the instantaneous value of the amplitude of said first sum signal falls, and signalling means connected to said first comparison circuit means for providing perceptible signals indicative of the fuel consumption upon receipt of said control signals.

Claim 6

A device as defined in any one of the preceding claims, wherein said first comparison circuit means include first and second threshold comparator circuits and a further comparison circuit arranged to provide a control signal only when the outputs from the first and second threshold comparator circuits are simultaneously at the same logic level.