Method for estimating a thawed volume present in liquid form in a tank

A method for estimating a volume of thawed liquid forming part of a content located inside a motor vehicle tank including at least one heating element arranged inside the motor vehicle tank, an inside thermometer positioned in the motor vehicle tank to measure a temperature θint0 of a liquid thawed inside the tank, an outside thermometer positioned out of the motor vehicle tank to measure a motor vehicle temperature θexti of an ambient air outside the motor vehicle, at least one of submerged level sensors, a motor vehicle speed measuring means, a computer processing unit for calculating estimated values of the volume of thawed liquid and acquiring actual values of an inside temperature of the content of the motor vehicle tank, an outside temperature of the ambient air outside the motor vehicle, a motor vehicle speed, a liquid level, via data interchange means connected to the inside thermometer, the outside thermometer, the at least one submerged sensors, the motor vehicle speed measuring means, and including a means for storing a first pre-established relationship, a second pre-established relationship, a third pre-established relationship, pre-established values and variable values, the method comprising:

• determining, the motor vehicle having started, during a regular time intervals (ΔTi);
• detecting the actual temperature (θexti) of the ambient aft outside the motor vehicle via the outside thermometer;
• estimating a heat-energy transfer (δES) between the content of the motor vehicle tank and external surroundings by using the first pre-established relationship based on the actual temperature (θexti) of the ambient aft outside the motor vehicle;
• estimating a heat-energy transfer (δEE) between the at least one heating element and the contents of the motor vehicle tank using the second preestablished relationship (R2(W)) based on a power (W) produced by the at least one heating element;
• estimating a quantity (δVi) of at least one of a thawed liquid and a refrozen liquid during the regular time interval (ΔTi) using a third preestablished relationship (R3(δEi)), based on the energy transfers (δEi=δES+δEE) having been determined;
• and
• estimating a volume of the thawed liquid present in the motor vehicle tank (Vwc=ΣδVi), based on a sum of the quantity of the thawed liquid and the quantity of the refrozen liquid during preceding successive time intervals.