Method and apparatus for operating an internal combustion engine

A method for operating an internal combustion engine in a motor vehicle, the internal combustion engine having a fuel/air feed device and a downstream exhaust system including an exhaust line passing through an exhaust casing, the exhaust line having a first exhaust gas line passing from the internal combustion engine to the exhaust casing and a second exhaust gas line passing from the exhaust casing to an exhaust gas aftertreatment device with an exhaust gas recirculation valve disposed in the second exhaust gas line upstream of the exhaust gas aftertreatment device, the exhaust gas recirculation valve being part of an exhaust gas recirculation device of the internal combustion engine, the method comprising:

• directing exhaust gas enthalpy from an exhaust gas flow of the internal combustion engine to a heat engine using the first exhaust gas line and a plurality of heat pipes inserted in the exhaust casing, each of the heat pipes having a first end inserted in the exhaust casing and a second end connected directly to the heat engine, such that the exhaust gas enthalpy is received by the first end of the each of the heat pipes from the exhaust gas flow and delivered to the heat engine through the second end of the each of the heat pipes, wherein the heat pipes in the exhaust casing are arranged upstream of the exhaust gas recirculation valve;
• reducing a temperature of the exhaust gas flow by the heat pipes so that an entire temperature drop of the exhaust gas required for recirculating the exhaust gas to an intake manifold of the internal combustion engine is provided by the heat pipes, whereby an exhaust gas recirculation line from the exhaust gas recirculation valve to the intake manifold is provided without an exhaust gas cooler;
• using the exhaust gas enthalpy to operate the heat engine and produce mechanical energy;
• and
• bypassing the heat pipes using a controllable bypass to achieve a rise in temperature for the catalytic exhaust gas aftertreatment device, the bypass being connected between the first exhaust line and the second exhaust line, and being connected to the second exhaust line upstream of the exhaust gas recirculation valve.