Embodiments for heating a vehicle cabin are disclosed. In one example, a method for heating a vehicle cabin comprises closing an exhaust throttle while diverting at least a portion of throttled exhaust gas through an exhaust gas recirculation (EGR) cooler coupled upstream of the throttle, and transferring heat from the EGR cooler to a heater core configured to provide heat to the vehicle cabin. In this way, exhaust heat may be directly routed to the cabin heating system.

Embodiments for heating a vehicle cabin are disclosed. In one example, a method for heating a vehicle cabin comprises closing an exhaust throttle while diverting at least a portion of throttled exhaust gas through an exhaust gas recirculation (EGR) cooler coupled upstream of the throttle, and transferring heat from the EGR cooler to a heater core configured to provide heat to the vehicle cabin. In this way, exhaust heat may be directly routed to the cabin heating system.

A method for detecting a failure of a charge air cooler placed in an air supply circuit of an engine, the circuit including an air filter and a compressor. The method is performed continuously and repeatedly. The method includes: determining temperature Tair of the air between the filter and the compressor, the temperature of the air Tapc between the compressor and the cooler, and the temperature of the air Tsras between the cooler and the engine; calculating the Tapc-Tsras/Tapc-Tair ratio, which is a parameter indicative of effectiveness of the cooler; comparing the parameter against a predetermined threshold effectiveness value; and making a diagnosis as to whether the cooler is operating correctly or incorrectly, on the basis of the comparison.

Embodiments for controlling an exhaust back-pressure valve are provided. In one example, a method for operating an engine comprises closing an exhaust back-pressure valve in response to a component temperature, adjusting intake and/or exhaust valve operation in response to closing the exhaust back-pressure valve to reduce cylinder internal exhaust gas recirculation (EGR), and while the exhaust back-pressure valve is closing, indicating degradation of an exhaust back-pressure system if a designated engine operating parameter remains constant. In this way, degradation of the exhaust back-pressure system may be diagnosed while maintaining combustion stability.

A non-return valve device for an internal combustion engine includes a valve housing comprising an aperture with a downstream end arranged in a duct housing. The aperture defines a flow cross section. A valve seat surrounds the flow cross section. A valve closing member, provided as leaf springs, adapts, closes or opens the flow cross section. A distance between each of the leaf springs in their maximum opened position at the downstream end of the aperture and the duct housing arranged opposite to each of the leaf springs has a maximum which is twice as large as a distance between each of the leaf springs in their maximum opened position and the valve seat arranged opposite to each of the leaf springs. Defining inner walls of the duct housing downstream of the valve housing are arranged so that the flow cross section is first continuously reduced and then continuously enlarged.

A non-return valve device for an internal combustion engine includes a valve housing comprising an aperture with a downstream end arranged in a duct housing. The aperture defines a flow cross section. A valve seat surrounds the flow cross section. A valve closing member, provided as leaf springs, adapts, closes or opens the flow cross section. A distance between each of the leaf springs in their maximum opened position at the downstream end of the aperture and the duct housing arranged opposite to each of the leaf springs has a maximum which is twice as large as a distance between each of the leaf springs in their maximum opened position and the valve seat arranged opposite to each of the leaf springs. Defining inner walls of the duct housing downstream of the valve housing are arranged so that the flow cross section is first continuously reduced and then continuously enlarged.

A number of variations may include a method including controlling low pressure EGR flow rates using air intake throttle with a variable swirl device or throttle valve, or using exhaust throttling.

Various methods and systems are provided for diagnosing an exhaust gas recirculation valve based on crankcase pressure. In one example, a method comprises indicating a condition of a valve disposed in a first exhaust passage downstream from a cylinder exhaust valve based at least in part on a crankcase pressure.

Various methods and systems are provided for diagnosing an exhaust gas recirculation valve based on crankcase pressure. In one example, a method comprises indicating a condition of a valve disposed in a first exhaust passage downstream from a cylinder exhaust valve based at least in part on a crankcase pressure.

An engine control system coordinates control of a pressure regulating mechanism associated with a turbocharger turbine and control of a variable valve actuating (VVA) mechanism for expanding the range of possible exhaust gas recirculation rates over a large portion of an engine operating map to provide EGR rates which are greater than typical present-day levels while mitigating engine pumping losses by causing the turbocharger to operate with better efficiency in some regions of the map where it otherwise would not. Turbocharger efficiency is improved by controlling the VVA mechanism to set the timing of operation of its respective cylinder valves in accordance with a predetermined correlation of operating efficiencies of a compressor to timing of operation of respective engine cylinder valves, causing the compressor to operate at points of better efficiency than it otherwise would without use of VVA.