Exhaust gas recirculation valves for a forced-induction internal combustion engine with exhaust gas recirculation

A device for building up the charge pressure required to avoid a drop in torque of an internal combustion engine, the device comprising:

• an exhaust gas turbocharger with a turbine and a compressor connected to the turbine by a shaft;
• an exhaust gas duct connected to an outlet of the turbine;
• an exhaust gas recirculation duct branching off from the exhaust gas duct with an exhaust gas recirculation duct outlet connected to a first inlet of a mixer with a mixer outlet connected to an inlet of the compressor;
• an exhaust gas recirculation valve in the exhaust gas recirculation duct;
• a fresh air inlet duct with an outlet connected to a second inlet of the mixer;
• and
• a control unit to prepare actuation signals for the exhaust gas recirculation valve;
• wherein the control unit:
• detects an actuation of an accelerator pedal;
• determines a target value for an exhaust gas recirculation rate in response to the actuation of the accelerator pedal;
• measures an instantaneous actual charge pressure;
• determines a setpoint exhaust gas recirculation rate based on the target value for the exhaust gas recirculation rate, a setpoint charge pressure corresponding to the target value for the exhaust gas recirculation rate, and the instantaneous actual charge pressure;
• calculates a control signal corresponding to an actuating variable for the exhaust gas recirculation valve, using the determined setpoint exhaust gas recirculation rate;
• and
• delivers the control signal to the exhaust gas recirculation valve to change an opening state of the exhaust gas recirculation valve;
• wherein the setpoint exhaust gas recirculation rate is calculated according to the following relation:
• eta_egr_soll=1−(1−eta_egr_soll_0)(P_lade_soll/P_lade_ist), where
• eta_egr_soll is the setpoint exhaust gas recirculation rate,
• eta_egr_soll_0 is the target value for the exhaust gas recirculation rate,
• P_lade_soll is the setpoint charge pressure, and
• P_lade_ist is the measured instantaneous actual charge pressure.

A method for building up the charge pressure required to avoid a drop in torque of an internal combustion engine having an exhaust gas turbocharger, which has a fresh air inlet duct, an exhaust gas recirculation duct with an exhaust gas recirculation valve, and a mixer, the method including:

• detecting an actuation of an accelerator pedal;
• determining a target value for an exhaust gas recirculation rate in response to the actuation of the accelerator pedal;
• measuring an instantaneous actual charge pressure;
• determining a setpoint exhaust gas recirculation rate based on the target value for the exhaust gas recirculation rate, a setpoint charge pressure corresponding to the target value for the exhaust gas recirculation rate, and the measured instantaneous actual charge pressure;
• calculating a control signal corresponding to an actuating variable for the exhaust gas recirculation valve, using the determined setpoint exhaust gas recirculation rate;
• and
• delivering the control signal to the exhaust gas recirculation valve to change an opening state of the exhaust gas recirculation valve;
• wherein the setpoint exhaust gas recirculation rate is calculated according to the following relation:
• eta_egr_soll=1−(1−eta_egr_soll_0)(P_lade_soll/P_lade_ist), where
• eta_egr_soll is the setpoint exhaust gas recirculation rate,
• eta_egr_soll_0 is the target value for the exhaust gas recirculation rate,
• P_lade_soll is the setpoint charge pressure, and
• P_lade_ist is the measured instantaneous actual charge pressure.