Abstract: A method for detecting whether an injector with a valve controlled by a PWM signal of an SCR system is at least partially clogged, the system including a pump, or a positive-displacement pump, driven by a motor and pressure of which is controlled by a controller that continuously measures the pressure and/or another parameter characteristic of energy transmitted by the motor to the pump. According to the method, during normal operation of the SCR system, specific portions of one of the measurements are compared with equivalent portions stored in a memory.

Abstract: A method for detecting whether an injector with a valve controlled by a PWM signal of an SCR system is clogged, the SCR system including a rotary positive-displacement pump driven by a motor and pressure of which is controlled by a controller that continuously measures rotational speed of the motor and pressure at an outlet of the pump. During operation of the SCR system at a given pressure: the associated average rotational speed is measured; the speed is held at the measured value; a curve of a change in pressure is compared to reference curves stored in a memory and a condition of the injector, for example whether the injector is clogged or not, is deduced therefrom.

Abstract: SCR system for treating the exhaust gases of an internal combustion engine, this system comprising a line for feeding a urea solution into the exhaust gases and a pump capable both of feeding the urea solution into the exhaust gases and of purging at least one part of the line by sucking a gas therethrough by means of a suction device, this system also comprising a control unit capable of activating and/or deactivating the operation of the pump and that of the suction device in a sequential manner in the course of one and the same purge procedure.

Abstract: A method for detecting whether an injector with a valve controlled by a PWM signal of an SCR system is at least partially clogged, the system including a pump, or a positive-displacement pump, driven by a motor and pressure of which is controlled by a controller that continuously measures the pressure and/or another parameter characteristic of energy transmitted by the motor to the pump. According to the method, during normal operation of the SCR system, specific portions of one of the measurements are compared with equivalent portions stored in a memory.

Abstract: A method for detecting whether an injector with a valve controlled by a PWM signal of an SCR system is clogged, the SCR system including a rotary positive-displacement pump driven by a motor and pressure of which is controlled by a controller that continuously measures rotational speed of the motor and pressure at an outlet of the pump. During operation of the SCR system at a given pressure: the associated average rotational speed is measured; the speed is held at the measured value; a curve of a change in pressure is compared to reference curves stored in a memory and a condition of the injector, for example whether the injector is clogged or not, is deduced therefrom.

Abstract: Method for controlling an injector intended for injecting a pollution-control liquid additive into the exhaust gases of an internal combustion engine at a flow rate governed by a given frequency and opening time of the injector, the injector having a calibration curve that establishes, at given frequency, pressure, temperature and nature of the liquid, the amount of liquid injected during an opening of the injector as a function of the duration of this opening, this curve comprising at least one linear zone (calibration line) and a non-linear zone, said method being characterized in that in the linear zone the parameters of the calibration line are used and in the non-linear zone use is made of a set opening time and a variable frequency according to at least one calibration point established for this purpose. SCR system to which this method can be applied.

Abstract: Method for heating a urea SCR system using at least two resistive heating elements (R1, R2), one of which (R1) is intended for heating one or some (part(s) of) component(s) always in contact with a substantial amount of urea and the other (R2) is intended for heating one or some (part(s) of) component(s) which are sometimes not in contact with a substantial amount of urea, and according to which, when starting the system in freezing conditions, the resistive element R1 is activated but the resistive element R2 is activated only when its component is actually in contact with a substantial amount of urea.

Abstract: SCR system for treating the exhaust gases of an internal combustion engine, this system comprising a line for feeding a urea solution into the exhaust gases and a pump capable both of feeding the urea solution into the exhaust gases and of purging at least one part of the line by sucking a gas therethrough by means of a suction device, this system also comprising a control unit capable of activating and/or deactivating the operation of the pump and that of the suction device in a sequential manner in the course of one and the same purge procedure.

Abstract: Process for heating a urea component of a SCR system comprising besides said component, a temperature sensor, a heating device in the component, according to which: 1. the temperature (Tcpt) of the liquid in the component is determined and compared to a 1st setpoint (T0); 2. if the temperature (Tcpt) is greater than the 1st setpoint (T0), step 1 is repeated; 3. if the temperature (Tcpt) is less than or equal to the 1st setpoint (T0), the heating device is actuated, 4. the time during which the heating device is actuated is measured and the heating device is stopped if this time is greater than a time t1; 5. the temperature (Tcpt) is determined after a time t2 and compared to a 2nd setpoint (T1 with T1>T0); if the temperature (Tcpt) is less than or equal to the 2nd setpoint (T1) the heating device is actuated and step 4 is repeated; 6. if the temperature (Tcpt) is greater than the 2nd septoint (T1), the heating device is stopped and step 1 is repeated.

Abstract: SCR system for treating the exhaust gases of an internal combustion engine, this system comprising a line for feeding a urea solution into the exhaust gases and a pump capable both of feeding the urea solution into the exhaust gases and of purging at least one part of the line by sucking a gas therethrough by means of a suction device, this system also comprising a control unit capable of activating and/or deactivating the operation of the pump and that of the suction device in a sequential manner in the course of one and the same purge procedure.

Abstract: Method for controlling an injector intended for injecting a pollution-control liquid additive into the exhaust gases of an internal combustion engine at a flow rate governed by a given frequency and opening time of the injector, the injector having a calibration curve that establishes, at given frequency, pressure, temperature and nature of the liquid, the amount of liquid injected during an opening of the injector as a function of the duration of this opening, this curve comprising at least one linear zone (calibration line) and a non-linear zone, said method being characterized in that in the linear zone the parameters of the calibration line are used and in the non-linear zone use is made of a set opening time and a variable frequency according to at least one calibration point established for this purpose. SCR system to which this method can be applied.

Abstract: Method for heating a urea SCR system using at least two resistive heating elements (R1, R2), one of which (R1) is intended for heating one or some (part(s) of) component(s) always in contact with a substantial amount of urea and the other (R2) is intended for heating one or some (part(s) of) component(s) which are sometimes not in contact with a substantial amount of urea, and according to which, when starting the system in freezing conditions, the resistive element R1 is activated but the resistive element R2 is activated only when its component is actually in contact with a substantial amount of urea.