Method for managing the operation of a refrigerated lorry for transporting heat-sensitive products, of the indirect injection type, where the lorry is provided with: - at least one chamber for storing products, - a reserve of a cryogenic fluid such as liquid nitrogen or liquid CO 2, - a heat exchanger system, wherein the cryogenic fluid circulates, exchanger system comprising at least one heat exchanger inside said at least one chamber, - as well as an air circulation system, for example of the fan type, capable of placing the air inside the chamber in contact with the cold walls of the exchanger(s) inside said at least one chamber; characterised by the implementation of the following measures: a) temperature sensors (3, 6, 8) capable of measuring the following temperatures are arranged: - T int: the temperature of the air at the inlet of the exchanger; - T fluid outlet: the temperature of the cold vapours exiting from the exchanger; and - T blown air: the temperature of the "blown" air, i.e. the temperature of the air, which has become cold, after it has passed through the exchanger. b) and an operation of defrosting is commanded of said exchanger when the following conditions are achieved: - the pinching of the exchanger: T int -T fluid outlet, is greater than a given setpoint Setpoint pinching, for a cumulative time t 1, and - the temperature difference T int -T blown air, is greater than a given setpoint Setpoint Tint-Tblown air, for the cumulative time t 1. - at least one chamber for storing products, - a reserve of a cryogenic fluid such as liquid nitrogen or liquid CO 2, - a heat exchanger system, wherein the cryogenic fluid circulates, exchanger system comprising at least one heat exchanger inside said at least one chamber, - as well as an air circulation system, for example of the fan type, capable of placing the air inside the chamber in contact with the cold walls of the exchanger(s) inside said at least one chamber; a) temperature sensors (3, 6, 8) capable of measuring the following temperatures are arranged: - T int: the temperature of the air at the inlet of the exchanger; - T fluid outlet: the temperature of the cold vapours exiting from the exchanger; and - T blown air: the temperature of the "blown" air, i.e. the temperature of the air, which has become cold, after it has passed through the exchanger. - T int: the temperature of the air at the inlet of the exchanger; - T fluid outlet: the temperature of the cold vapours exiting from the exchanger; and - T blown air: the temperature of the "blown" air, i.e. the temperature of the air, which has become cold, after it has passed through the exchanger. b) and an operation of defrosting is commanded of said exchanger when the following conditions are achieved: - the pinching of the exchanger: T int -T fluid outlet, is greater than a given setpoint Setpoint pinching, for a cumulative time t 1, and - the temperature difference T int -T blown air, is greater than a given setpoint Setpoint Tint-Tblown air, for the cumulative time t 1. - the pinching of the exchanger: T int -T fluid outlet, is greater than a given setpoint Setpoint pinching, for a cumulative time t 1, and - the temperature difference T int -T blown air, is greater than a given setpoint Setpoint Tint-Tblown air, for the cumulative time t 1.