Method for cold-start pre-warming of a pressure-charged internal combustion engine and/or of an exhaust gas aftertreatment device
A method for cold start pre-warming of a pressure-charged internal combustion engine and/or of an exhaust gas aftertreatment device of a internal combustion engine, includes arranging a cold-starting aid in the intake duct for warming the charge air while the engine is stationary. The internal combustion engine has at least one working cylinder with at least one inlet valve and at least one outlet valve and further includes a device for setting a valve position. The internal combustion engine can be pressure-charged by a pressure-charging device operable by an electric motor. In the method, after detection of a cold start of the internal combustion engine: the cold-starting aid is activated while the engine is stationary; electric-motor operation of the pressure-charging device is activated; and a valve overlap between at least one inlet valve and at least one outlet valve is set.
1. A method for cold-start pre-warming at least one of a pressure-charged internal combustion engine and an exhaust gas aftertreatment device of the internal combustion engine,
wherein a cold-starting aid is arranged in an intake duct and warms charge air while the internal combustion engine is stationary, and
wherein the internal combustion engine comprises at least one working cylinder, which in each case has at least one inlet valve, which is connected to the intake duct, and at least one outlet valve, which is connected to an exhaust system, and further comprises a setting device for setting a valve position, and a pressure-charging device operable by an electric motor;
the method, comprising the steps of
detecting a cold start of the internal combustion engine; and
after the detecting of the cold start,
activating the cold-starting aid while the engine is stationary;
activating operation of the pressure-charging device using the electric motor; and
setting, by the setting device, a valve overlap between at least one inlet valve and at least one outlet valve of a working cylinder to deliver at least some of the charge air delivered by the pressure-charging device and pre-warmed by the cold-starting aid directly into the exhaust system.
2. The method according to claim 1 , wherein the pressure-charging device operable by the electric motor is one of an exhaust turbocharger with electric motor assistance and an electric compressor.
3. The method according to claim 1 , wherein the cold-starting aid is one of a flame-starting device, a glow plug, and a glow grid.
4. The method according to claim 1 , wherein the setting device for setting the valve position sets at least one predetermined angular position of the crankshaft, which produces the valve overlap and which, for this purpose, activates a starter motor of the internal combustion engine or a crankshaft starter generator.
5. The method according to claim 1 , wherein the internal combustion engine includes an electromagnetic valve gear, which is activated by the setting device to set the valve overlap.
6. The method according to claim 1 , wherein the internal combustion engine is equipped with at least two camshafts and at least one camshaft phase adjuster, at least one of the camshaft phase adjusters is activated in such a way as to increase the valve overlap in the step of setting.
7. The method according to claim 1 , wherein in the step of setting the valve overlap, the valve overlap is in each case set in succession for the next working cylinder or cylinders to be ignited during the starting process.
8. The method according to claim 1 , wherein the internal combustion engine is embodied as an in-line six-cylinder engine and, in the step of setting the valve overlap, the crankshaft is turned three times in succession, in each case by 120°, in each case to set one of two synchronized working cylinders that are the next to be ignited during the starting process to the charge-exchange top dead center position (CETDC).
9. The method according to claim 1 , wherein in the step of setting the valve overlap, a slow continuous crankshaft rotation takes place while the engine is stationary.
10. The method according to claim 1 , wherein the internal combustion engine operates with self-ignition.
11. The method according to claim 10 , wherein the internal combustion engine is a diesel engine.
12. A motor vehicle, comprising
an internal combustion engine having an intake duct, at least one working cylinder, which in each case has at least one inlet valve, which is connected to the intake duct, and at least one outlet valve, which is connected to an exhaust system;
a pressure-charging device, which can be operated by electric motor, for pressure-charging the internal combustion engine;
a setting device for setting an internal combustion engine having an intake take valve position of the working cylinders of the internal combustion engine;
an exhaust gas aftertreatment device;
a cold-starting aid, arranged in the intake duct, for warming the charge air while the engine is stationary; and
a control device for cold-start pre-warming of at least one of the internal combustion engine and of the exhaust gas aftertreatment device while the engine is stationary, using the method according to claim 1 .