Abstract: Disclosed is a method for determination of the water content of a mixed alcohol/gasoline fuel in an internal combustion engine of a vehicle, which includes the stages of: determination of a first value for alcohol content of the fuel using a measurement of combustion richness; determination of a second value for alcohol content of the fuel using a measurement recorded by a sensor for measurement of the electrical conductivity of the fuel; comparison of the first value and the second value; and, when the first value is lower than the second value, determination of the water content of the fuel by assigning a predetermined value for water content associated with the pair consisting of the first value and of the second value for alcohol content.

Abstract: A method for determining the alcohol content of a fuel mixture for a vehicle internal combustion engine that can be sequentially supplied with two types of fuel having a predetermined composition, at least one of which contains a mixture of gasoline and alcohol, includes, after feeding an amount of new fuel into the vehicle tank previously containing an amount of old fuel mixture, determining the first moment at which the new fuel mixture is supplied to the first injector. After the first moment, and from the first sufficiently long period during which the operating state of the engine is stabilized, determining an optional variation trend of the richness of the air/fuel mixture relative to a previously measured richness, deducing the type of new fuel supplied and, by cross-checking this information with the respective volumes of old and new fuels in the tank, determining the alcohol content of the new mixture.

Abstract: Disclosed is a method for determination of the water content of a mixed alcohol/gasoline fuel in an internal combustion engine of a vehicle, which includes the stages of: determination of a first value for alcohol content of the fuel using a measurement of combustion richness; determination of a second value for alcohol content of the fuel using a measurement recorded by a sensor for measurement of the electrical conductivity of the fuel; comparison of the first value and the second value; and, when the first value is lower than the second value, determination of the water content of the fuel by assigning a predetermined value for water content associated with the pair consisting of the first value and of the second value for alcohol content.

Abstract: A process for determining the pressure prevailing in a fuel injection manifold of an internal combustion engine includes supplying the feeding pump (11) with fuel such that the injection manifold will be supplied with fuel at the feeding pressure, measuring the pressure prevailing in the injection manifold (14) with the pressure sensor (18) when the fuel is at the feeding pressure, deducing therefrom the percentage of error (e) of the pressure sensor, and memorizing this error, establishing a law of linear decrease of this error, between the feeding pressure and the lower limit of the range of maximum precision of the sensor, and deducing therefrom, for each value of pressure measured by the sensor between the feeding pressure and the lower pressure limit, the real value of the pressure of the fuel in the injection manifold, to correct the quantity of injected fuel.

Abstract: Apparatus for measuring flux density within the surface of a ferromagnetic material (24) includes a probe (10) having an end for location on or adjacent the surface of the material (24), a first sensor at the said end of the probe (10) and capable of producing a first output signal representative of the strength of the magnetic field to which said first sensor is subjected, and a second sensor at the remote end of the probe (10) and capable of producing a second output representative of the strength of the magnetic field to which said second sensor is subjected. An electronic circuit produces a difference signal representing the difference between the first and second outputs, and an output device (14) displays and/or records said difference signal (16).