A heat exchanger including a honeycomb structure having partition walls defining fluid cells extending between inflow and outflow end faces, and inner and outer peripheral walls. A first outer cylinder contacts the outer peripheral wall. A first inner cylinder having inflow and outflow ports for the fluid has an outer peripheral surface that contacts the inner peripheral wall. A second inner cylinder having inflow and outflow ports for the fluid is spaced on a radially inner side of the inner peripheral wall. The inflow port of the first inner cylinder is closer to the inflow end face than the outflow end face in an axial direction of the honeycomb structure. The outflow port of the second inner cylinder is closer to the outflow end face than the inflow end face in the axial direction of the honeycomb structure.

A modular system for exhaust heat recovery devices has heat exchangers which differ by different external dimensions, in particular different cross-sections, and identically configured exhaust gas carrying housings into each of which one of the heat exchangers can be introduced. Various tubular adapters are adapted to the external dimensions of the heat exchangers and are used to fasten the associated heat exchanger at its connection ends to the exhaust gas carrying housing. Furthermore, a tubular adapter for a corresponding modular system and a vehicle which has a corresponding exhaust heat recovery device are provided.

Systems and methods are provided for an engine system having a split exhaust system. In one example, a system may include an engine having a plurality of cylinders, each of the plurality of cylinders including first and second exhaust ports, the first and second exhaust ports arranged in a non-alternating pattern across the plurality of cylinders and along a cylinder head, a blowdown exhaust manifold coupled to the first exhaust ports and an exhaust passage, and a scavenge exhaust manifold coupled to the second exhaust ports and an intake passage of the engine. In this way, the first and second exhaust ports may be arranged to enhance turbocharger performance characteristics.

Methods and systems are provided for extending a duration of engine idle-stop while reducing a frequency of engine restart from idle-stop. In one example, in response to engine restart conditions where combustion torque is not necessary, an engine can be rotated electrically, without fuel delivery, via an electric motor. The unfueled engine spinning via the motor drives an FEAD which in turns drives an actuator coupled to the FEAD, such as an AC compressor or an automatic transmission oil pump.

An exhaust system with a first and a second exhaust conduit arranged in a parallel flow arrangement. The exhaust system further includes an exhaust gas heat recovery (EGHR) heat exchanger coupled to an exterior of the first exhaust conduit. The exhaust system further includes a first flow control valve controlling the flow of exhaust gas into the EGHR heat exchanger from the first exhaust conduit and a second flow control valve controlling the flow of exhaust gas through the second exhaust conduit.

A control system for use in a fluid flow application includes a heater and a control device. The heater has at least one resistive heating element and the heater is operable to heat fluid. The control device determines at least one flow characteristic of a fluid flow based on a heat loss of the at least one resistive heating element and determines a mass flow rate of the fluid based on the at least one flow characteristic and a property of the at least one resistive heating element. And the property of the at least one resistive heating element includes a change in resistance of the at least one resistive heating element under a given heat flux density.

A method for operating a heater system including a resistive heating element having a material with a non-monotonic resistivity vs. temperature profile is provided. The method includes heating the resistive heating element to within a limited temperature range in which the resistive heating element exhibits a negative dR/dT characteristic, operating the resistive heating element within an operating temperature range that at least partially overlaps the limited temperature range, and determining a temperature of the resistive heating element such that the resistive heating element functions as both a heater and a temperature sensor. The resistive heating element can function as a temperature sensor in a temperature range between about 500 C. and about 800 C., and the non-monotonic resistivity vs. temperature profile for the material of the resistive heating element can have a local maximum and a local minimum.

Methods and systems are provided for diagnostics of an exhaust tuning valve during vehicle-off conditions. In one example, the engine may be reverse rotated, unfueled while the position of the exhaust is varied and an intake air flow is estimated at each position of the exhaust tuning valve. The exhaust tuning valve may be diagnosed based on a change in air flow with the variation in the position of the exhaust tuning valve.

A heater is provided that includes at least one resistive heating element having a material with a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile. The heater can include a plurality of circuits disposed in a fluid path to heat fluid flow.

A heater system for an exhaust system is provided. The heater system includes a heater disposed in an exhaust conduit. The heater includes a plurality of heating elements disposed in the exhaust conduit. A heating control module controls the plurality of heating elements differently according to operating conditions specific to each heating element. In other forms, the heater system for an exhaust system has a plurality of heating zones, instead of a plurality of heating elements. The heating control module controls the plurality of heating zones differently according to operating conditions specific to each heating zone.