In a method for estimating water content of exhaust gas, a first gas concentration at a first position in an exhaust passage, a second gas concentration at a second position downstream of the first position, and a gas temperature at the second position are obtained. A saturated water vapor at the gas temperature is calculated as a water content at the second position. By using the water content at the second position and the second gas concentration, an excess air amount of a fuel-air mixture supplied to a combustion apparatus is calculated based on a chemical reaction formula of combustion of the mixture. By using the excess air amount and the first gas concentration, a water content at the first position is estimated.

A vehicle comprising an internal combustion engine, an electrical heated type catalyst device provided in an exhaust passage of the internal combustion engine and including a conductive substrate generating heat upon energization and a catalyst heated through the conductive substrate, and a control device, the control device comprising an internal moisture calculating part calculating an amount of internal moisture comprised of an amount of moisture present at an inside of the catalyst device and an engine output control part controlling the output of the internal combustion engine based on a required vehicle output and the amount of internal moisture. The engine output control part is configured so that if moisture is present at the inside of the catalyst device, it restricts the output of the internal combustion engine to a lower output when the internal moisture is large compared to when it is small.

A preset compression ratio of a gasket is set to be larger at a center segment than at fixation segments. In order to set the preset compression ratio in the above-described manner, a depth of a center-segment-side bottom surface of a cover is set to be smaller than a depth of each fixation-segment-side bottom surface at the cover. In this way, even when a phenomenon, which causes a reduction of the compression ratio of the center segment of the gasket relative to the compression ratio of the fixation segments, occurs, it is possible to limit the reduction of the compression ratio of the center segment to a value that is lower than the compression ratio of the fixation segment.

Methods and systems are provided for exhaust gas heat recovery at an exhaust gas heat exchanger. Exhaust gas may flow in both directions through an exhaust bypass passage and the heat exchanger coupled to the bypass passage. Hot or cold EGR may be delivered from the exhaust passage to the engine intake manifold and heat from the exhaust gas may be recovered at the heat exchanger.

In an engine, an intake duct is provided with an intercooler disposed downstream of an intake air compressor. An EGR pipe is provided with an EGR valve and an EGR cooler. An ECU determines a generation of a condensed water in the EGR cooler, the generation of the condensed water in a merging portion where a fresh air and an EGR gas merge with each other, and the generation of the condensed water in the intercooler. When it is determined that the condensed water is generated in any of these portions, the ECU performs a corresponding countermeasure for restricting the generation of the condensed water.

A preset compression ratio of a gasket is set to be larger at a center segment than at fixation segments. In order to set the preset compression ratio in the above-described manner, a depth of a center-segment-side bottom surface of a cover is set to be smaller than a depth of each fixation-segment-side bottom surface at the cover. In this way, even when a phenomenon, which causes a reduction of the compression ratio of the center segment of the gasket relative to the compression ratio of the fixation segments, occurs, it is possible to limit the reduction of the compression ratio of the center segment to a value that is lower than the compression ratio of the fixation segment.

Methods and systems are provided for exhaust heat recovery and EGR cooling via a single heat exchanger. In one example, a method may include selecting a specific mode of operation of an engine exhaust system with the heat exchanger based on engine operating conditions and an estimated fuel efficacy factor. The fuel efficiency factor may take into account fuel efficacy benefits from EGR and exhaust heat recovery.

Methods and systems are provided for removing moisture from an engine exhaust system. In one example, a method includes, during a vehicle key-off condition, in response to a higher than threshold exhaust moisture level and a lower than threshold engine run time during an immediately prior drive cycle, operating an electric air compressor to remove the moisture accumulated in the exhaust manifold.

Provided is an engine knocking detection apparatus capable of reasonably implementing necessary measures for water and dust proofing and against breaking of a cable, and the like at low cost as well as precisely detecting and effectively suppressing or avoiding knocking while suppressing cost and weight increases as much as possible. The engine knocking detection apparatus is adapted to detect knocking in an engine that adopts a flywheel magneto ignition system with an ignition coil unit securely attached to a cylinder, the ignition coil unit including an iron core, a coil wound around the iron core, and a control circuit board attached to the coil, and has an accelerometer for knocking detection attached to the iron core of the ignition coil unit.

A method for controlling an emission amount in an exhaust gas stream emitted from a power generation system is presented. The method includes determining a pre-catalyst emission level using a combustion engine model. The method further includes determining a post-catalyst emission level using a three-way catalyst model based on the pre-catalyst emission level. Furthermore, the method includes determining an adjusted post-catalyst emission level based on the post-catalyst emission level. Moreover, the method includes determining a difference between the post-catalyst emission level and the adjusted post-catalyst emission level and comparing the difference with a threshold value. Additionally, the method includes determining whether to adjust an actual value of an engine operating parameter based on the comparison such that the emission amount in the exhaust gas stream is maintained below an emission regulatory limit. An engine controller and a power generation system employing the method are also presented.