摘要:
A table provides a value (RFAtab) corresponding to the closure lag of the intake valve (2) associated with the cylinder (41), as a function of engine speed (N), the closure of said valve (2) being controlled as a function of said lag. During operation at a speed stabilized under a heavy load, the applied closure lag is gradually varied stepwise ( epsilon ), based on the stored value. The cylinder load is measured and compared before and after each successive step and the stored closure lag value (RFAtab) is updated when a comparison indicates an increase in said load, until a maximum value is detected for the latter.
摘要:
A reductant delivery unit (16) is provided unit for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (18) associated with an exhaust gas flow path (13). The injector has a fluid inlet (28) and a fluid outlet (30) with the fluid inlet receiving a source of urea solution and the fluid outlet communicating directly with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. Supply structure (32) defines the fluid inlet and includes a cup (37) coupled to a body (18) of the injector and a supply tube (29) integral with the cup to define a single member. The supply tube is coupled with the source (27) of urea solution to deliver urea solution to the fluid inlet. The supply tube is heated by a heat source (33) so that an entire volume of the urea solution delivered to the fluid inlet is heated.
摘要:
A reductant delivery unit (10) is provided for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (10) constructed and arranged to be associated with an exhaust gas flow path (14) upstream of a SCR catalytic converter (17). The fluid injector has a fluid inlet (13) and a fluid outlet (15) with the fluid inlet being constructed and arranged to receive a source of urea solution and the fluid outlet being constructed and arranged to communicate directly with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. An interface (24) is constructed and arranged to couple the fluid injector to the gas flow path. The interface defines a thermal barrier constructed and arranged to decoupled a body of the injector from exposure to heat in the exhaust gas flow path.
摘要:
A reductant delivery unit (10) is provided for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (10) constructed and arranged to be associated with an exhaust gas flow path (14) upstream of a SCR catalytic converter (17). The fluid injector has a fluid inlet (13) and a fluid outlet (15) with the fluid inlet being constructed and arranged to receive a source of urea solution and the fluid outlet being constructed and arranged to communicate directly with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. An interface (24) is constructed and arranged to couple the fluid injector to the gas flow path. The interface defines a thermal barrier constructed and arranged to decoupled a body of the injector from exposure to heat in the exhaust gas flow path.
摘要:
According to the invention, a set-point position ( alpha c) is calculated continuously for an event concerning the valve. Upon detection of a change of the set-point ( alpha c) or the engine rotation speed (N), (a) the setting of the new set-point is controlled in open loop at least during the first engine cycle following the set-point change detection and (b) the taking-up of the new set-point is then controlled in closed loop during the following engine cycles. The control is applied to an event triggering means with an avance (AV) with respect to the event. At each open loop control cycle, said advance is read in a stored table, as a function of the engine rotation speed (N) and of the set-point position ( alpha c) calculated for the event. Application to the control of the variable opening and closing of an intake valve.