초록 ▼

A control method for an internal combustion engine supercharged by means of a turbocharger provided with a turbine and with a compressor; the control method contemplates the steps of: establishing at least one operating limit curve on a Reduced Mass Flow Rate/Compression Ratio map; establishing at l

A control method for an internal combustion engine supercharged by means of a turbocharger provided with a turbine and with a compressor; the control method contemplates the steps of: establishing at least one operating limit curve on a Reduced Mass Flow Rate/Compression Ratio map; establishing at least one intervention curve of a wastegate valve which adjusts a bypass pipe of the turbine on a Reduced Mass Flow Rate/Compression Ratio map; establishing at least one intervention curve of a Poff valve which adjusts a bypass pipe of the compressor on a Reduced Mass Flow Rate/Compression Ratio map; using the operating limit curve to limit the pressure target downstream of the compressor used by the engine control; controlling the opening of the wastegate valve if the intervention curve of the wastegate valve is exceeded; and controlling the opening of the Poff valve if the intervention curve of the Poff valve is exceeded.

대표청구항 ▼

1. A control method of an internal combustion engine (1) supercharged by means of a turbocharger (12) provided with a turbine (13) and with a compressor (14); the control method comprises the steps of: establishing at least one operating limit curve (29; 30) on a Reduced Mass Flow Rate/Compression R

1. A control method of an internal combustion engine (1) supercharged by means of a turbocharger (12) provided with a turbine (13) and with a compressor (14); the control method comprises the steps of: establishing at least one operating limit curve (29; 30) on a Reduced Mass Flow Rate/Compression Ratio map;establishing at least one intervention curve (31; 32) of a wastegate valve (16) which adjusts a bypass pipe (15) of the turbine (13) on a Reduced Mass Flow Rate/Compression Ratio map;establishing at least one intervention curve (33; 34) of a Poff valve (19) which adjusts a bypass pipe (18) of the compressor (14) on a Reduced Mass Flow Rate/Compression Ratio map;using the operating limit curve (29; 30) to limit the pressure target downstream of the compressor (14) used by the engine control;controlling the opening of the wastegate valve (16) if the intervention curve (31; 32) of the wastegate valve (16) is exceeded; andcontrolling the opening of the Poff valve (19) if the intervention curve (33; 34) of the Poff valve (19) is exceeded. 2. A method according to claim 1, comprising the further steps of: determining a first operating limit curve (29), a first intervention curve (31) of the wastegate valve (16), and a first intervention curve (33) of the Poff valve (19) according to a curve (27) which limits the rotation speed of the turbocharger (12); anddetermining a second operating limit curve (30), a second intervention curve (32) of the wastegate valve (16), and a second intervention curve (34) of the Poff valve (19) according to a curve (28) which limits the surge of the turbocharger (12). 3. A method according to claim 2, wherein the step of determining the first curves (29, 31, 33) contemplates the further steps of: determining the curve (27) which limits the rotation speed of the turbocharger (12); anddetermining for each first curve (29, 31, 33) a corresponding threshold (S1, S3, S5) which establishes the distance between the first curve (29, 31, 33) and the curve (27) which limits the rotation speed of the turbocharger (12). 4. A method according to claim 2, wherein the step of determining the second curves (30, 32, 34) contemplates the further steps of: determining the curve (28) which delimits the surge of the turbocharger (12); anddetermining for each second curve (30, 32, 34) a corresponding threshold (S2, S4, S6) which establishes the distance between the second curve (30, 32, 34) and the curve (28) which delimits the surge of the turbocharger (12). 5. A method according to claim 3, wherein the second curves (28, 30, 32, 34) are independent from a reduced limit speed (NtCR) of the turbocharger (12). 6. A method according to claim 3, wherein the first curves (27, 29, 31, 33) are dependent on a reduced limit speed (NtCR) of the turbocharger (12). 7. A method according to claim 6, comprising the further steps of: establishing a predetermined limit speed (Ntc) of the turbocharger (12);calculating the current reduced limit speed (NtCR) of the turbocharger (12) using the predetermined limit speed (Ntc) of the turbocharger (12) and the absolute temperature (To) upstream of the compressor (14); anddetermining the first curves (27, 29, 31, 33) to be used according to the current reduced speed limit (NtCR) of the turbocharger (12). 8. A method according to claim 7, wherein the current reduced speed limit (NtCR) of the turbocharger (12) is calculated by using the following equation: NtcR=Ntc·TorifToNtc limit speed of the turbocharger (12);NtCR reduced limit speed of the turbocharger (12);To absolute temperature upstream of the compressor (14);Torif absolute reference temperature. 9. A method according to claim 6, comprising the further steps of: parameterizing the first curves (27, 29, 31, 33) according to the absolute temperature (To) upstream of the compressor (14); andupdating the first curves (27, 29, 31, 33) according to the absolute temperature (To) upstream of the compressor (14). 10. A method according to claim 1, wherein the step of using the operating limit curve (29; 30) for limiting the pressure target downstream of the compressor (14) used by the engine control contemplates the further steps of: determining the current reduced mass flow rate (QAHR) of the compressor (14);determining the current limit compression ratio (RC) of the compressor (14) according to the current reduced mass flow rate (QAHR) using the operating limit curve (29; 30);determining the current pressure upstream of the compressor (14);determining the maximum possible pressure downstream of the compressor (14) by multiplying the absolute pressure (Po) upstream of the compressor (14) by the maximum possible compression ratio (RC); andlimiting the pressure target downstream of the compressor (14) to the maximum pressure downstream of the compressor (14) if the pressure target downstream of the compressor (14) is higher than the maximum possible pressure downstream of the compressor (14). 11. A method according to claim 1, wherein the step of controlling the opening of the wastegate valve (16) if the intervention curve (31; 32) of the wastegate valve (16) is exceeded contemplates the further steps of: determining the current reduced mass flow rate (QAHR) of the compressor (14);determining the current compression ratio (RC) of the compressor (14); andcontrolling the opening of the wastegate valve (16) if the current compression ratio (RC) is higher than the compression ratio (RC) belonging to the intervention curve (31; 32) of the wastegate valve (16) at the current reduced mass flow rate (QAHR). 12. A method according to claim 1, wherein the step of controlling the opening of the Poff valve (19) if the intervention curve (33; 34) of the Poff valve (19) is exceeded contemplates the further steps of: determining the current reduced mass flow rate (QAHR) of the compressor (14);determining the current compression ratio (RC) of the compressor (14); andcontrolling the opening of the Poff valve (19) if the current compression ratio (RC) is higher than the compression ratio (RC) belonging to the intervention curve (33; 34) of the Poff valve (19) at the current reduced mass flow rate (QAHR). 13. A method according to claim 10, wherein the reduced mass flow rate (QAHR) of the compressor (14) is determined by using the following equation: QAHR=QAH·ToTorif·PoPorifQAH mass flow rate of the compressor (14);QAHR reduced mass flow rate of the compressor (14);To absolute temperature upstream of the compressor (14);Po absolute pressure upstream of the compressor (14);Torif absolute reference temperature;Porif absolute reference pressure.