| US 7,509,803 B2 | ||
| Method and device for controlling the speed of rotation of a turbosupercharger in an internal-combustion engine | ||
| Marco Panciroli, Ravenna (Italy) | ||
| Assigned to Magneti Marelli Powertrain S.p.A., Corbetta (Italy) | ||
| Filed on Jun. 30, 2006, as Appl. No. 11/427,934. | ||
| Claims priority of application No. 05425478 (EP), filed on Jul. 05, 2005. | ||
| Prior Publication US 2007/0033936 A1, Feb. 15, 2007 | ||
| Int. Cl. F02D 23/00 (2006.01) | ||
| U.S. Cl. 60—600 [60/602] | 14 Claims |
| 1. A method (1) for controlling the speed of rotation of a turbosupercharger (7) in an internal-combustion engine (2) of a motor vehicle comprising: a compressor (9), a turbine (8) for driving the compressor (9) in rotation under the action of the exhaust gases of the engine (2); and a wastegate valve (12) for regulating the flow rate of the exhaust gases provided at input to the turbine (8) for controlling the speed of rotation of the turbine (8) itself as a function of an objective supercharging pressure (POB) which indicates the value of the supercharging pressure that, on the basis of an objective map of the engine and of a set
of parameters of engine is required at output from said compressor (9); said method being characterized in that it comprises the steps of:
establishing a limit speed of rotation (Ntc) of the turbosupercharger (7); and during control of the speed of rotation of the turbine (8) performed through said wastegate valve (12), implementing the following steps:
measuring the pressure (PAMB) of the air taken in at input by the compressor (9);
determining the mass flow rate (QAH) of the compressor (9);
calculating, through a predetermined map (15a) that characterizes operation of the compressor (9) and as a function of the preset limit speed of rotation (Ntc), of the measured air pressure (PAMB), and of the mass flow rate (QAH), a limit supercharging pressure (SP1), which is correlated to the air pressure obtainable at output from the compressor (9) when the turbine (8) turns at a speed substantially equal to said pre-set limit speed (Ntc);
verifying whether the required objective supercharging pressure (POB) satisfies a pre-set relation with said calculated limit supercharging pressure (SP1), said preset relation being satisfied when said required objective pressure (POB) is higher than said limit supercharging pressure (SP1); and
in the case where said relation is satisfied, actuating said wastegate valve (12) for controlling the speed of rotation of the turbine (8) as a function of the limit supercharging pressure (SP1) so as to limit the speed of rotation of said turbosupercharger (7) to a value substantially equal to said preset limit speed (Ntc):
in the case where said relation is not satisfied, actuating said wastegate valve (12) for controlling the speed of rotation of the turbine (8) as a function of the objective supercharging pressure (POB) so as to achieve a supercharging corresponding to the objective pressure (POB)itself.
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