Method for operating an auto-ignition internal combustion engine
AssigneeMan Truck & Bus AG
InventorFranz Werner Pruemm
Life of this patent
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Abstract
A method for operating an auto-ignition internal combustion engine that is operable in a single substance mode in which the internal combustion engine is supplied with self-igniting liquid fuel, and a dual substance mode in which the internal combustion engine is supplied with the liquid fuel as an ignition agent and gaseous or liquid alternative fuel, includes operating the internal combustion engine in the dual-substance mode at an increased exhaust gas recirculation rate relative to the single-substance mode, and throttling an air supply in an intake system of the internal combustion engine such that a lambda value in an exhaust gas of the internal combustion engine is in a range greater than 1 up to 1.3.
Claims19
A method for operating an auto-ignition internal combustion engine that is operable in a single-substance mode in which the internal combustion engine is supplied with self-igniting liquid fuel, and a dual-substance mode in which the internal combustion engine is supplied with the liquid fuel as an ignition agent and natural gas, the internal combustion engine including combustion chambers, an injection device introducing liquid fuel into the combustion chambers, a pressure-charging device in an intake system precompressing combustion air for controlling a boost pressure, a feed device introducing the natural gas into the intake system in the dual-substance mode, an exhaust gas recirculation device that recirculates exhaust gases from the internal combustion engine into the intake system via an exhaust gas recirculation valve, at least one electronic control unit metering in fuel quantities in accordance with at least one of operation-specific parameters and parameters relating to driving dynamics such that a required power and defined exhaust gas limits are achieved in conjunction with an exhaust gas purification device, the method comprising:
- operating the internal combustion engine in the dual-substance mode at an increased exhaust gas recirculation rate relative to the single-substance mode;
- and
- throttling, in the dual-substance mode, an air supply in the intake system such that a lambda value in exhaust gas of the internal combustion engine is in a range greater than 1 and up to 1.3,
- wherein the steps of operating and throttling are performed to raise the temperature of the exhaust gas and ensure the presence of sufficient oxygen in the exhaust gas to allow oxidation of HC and CO to thereby ensure an effectiveness of oxidation catalysts in the exhaust gas purification device.
An internal combustion engine that is operable in a single-substance mode in which the internal combustion engine is supplied with self-igniting liquid fuel, and a dual-substance mode in which the internal combustion engine is supplied with the liquid fuel as an ignition agent and natural gas, the internal combustion engine comprising:
- combustion chambers;
- an injection device introducing the liquid fuel into the combustion chambers;
- at least one exhaust turbo charger in an intake system precompressing combustion air for controlling a boost pressure;
- a feed device introducing the natural gas into the intake system in the dual-substance mode;
- an exhaust gas recirculation device that recirculates exhaust gases from the internal combustion engine into the intake system via an exhaust gas recirculation valve;
- at least one electronic control unit metering in fuel quantities in accordance with at least one of operation-specific parameters and parameters relating to driving dynamics such that a required power and defined exhaust gas limits are achieved in conjunction with an exhaust gas purification device;
- wherein the exhaust gas recirculation device operates with an increased exhaust gas recirculation rate in the dual-substance mode relative to the single-substance mode;
- and
- a throttle element in the intake system configured to throttle, in the dual-substance mode, an air supply in the intake system such that a lambda value in exhaust gas of the internal combustion engine is in a range greater than 1 and up to 1.3
- wherein the lambda value and the increased exhaust gas recirculation rate raise the temperature of the exhaust gas and ensure the presence of sufficient oxygen in the exhaust gas to allow oxidation of HC and CO to thereby ensure an effectiveness of oxidation catalysts in the exhaust gas purification device.
Dependencies are inferred from the claim text.