Various methods and arrangements for improving fuel economy in decel fuel cut-off (DFCO) operation of an internal combustion engine are described. In one aspect, a catalytic converter bypass valve diverts the pumped air in DFCO mode from flowing through a catalytic converter. The diverted, pumped air may flow through a bypass line or be returned to the engine intake manifold through an exhaust gas recirculation return line. Another aspect of the invention relates to directing the diverted pumped air through an emission control device.

The EGR cooling structure includes a cylinder block having cylinders, and a cylinder head into which exhaust gas exhausted from the cylinders is collected. An exhaust emission control device is provided for purifying the exhaust gas exhausted from the cylinder head, and an EGR pipe is provided through which EGR gas of a part of the purified exhaust gas is introduced into an intake system. An EGR cooler is provided in the EGR pipe and cools the EGR gas with the cooling liquid. An exhaust gas passage leading from the cylinders to the exhaust gas purification device is curved when seen from a side, and the EGR cooler is disposed in the space surrounded by the cylinder block, the cylinder head, and the exhaust gas purification device.

The EGR cooling structure includes a cylinder block having cylinders, and a cylinder head into which exhaust gas exhausted from the cylinders is collected. An exhaust emission control device is provided for purifying the exhaust gas exhausted from the cylinder head, and an EGR pipe is provided through which EGR gas of a part of the purified exhaust gas is introduced into an intake system. An EGR cooler is provided in the EGR pipe and cools the EGR gas with the cooling liquid. An exhaust gas passage leading from the cylinders to the exhaust gas purification device is curved when seen from a side, and the EGR cooler is disposed in the space surrounded by the cylinder block, the cylinder head, and the exhaust gas purification device.

An upper-limit threshold value and a lower-limit threshold value of a fore-and-aft differential pressure of an EGR control valve is calculated based on an intake-air quantity detected by an airflow meter. An actual fore-and-aft differential pressure of the EGR control valve is calculated from detected values of an upstream-side pressure sensor and a downstream-side pressure sensor. Then, these threshold values are compared with the actual fore-and-aft differential pressure, and when the actual fore-and-aft differential pressure exceeds the upper-limit threshold value or when the actual fore-and-aft differential pressure is less than the lower-limit threshold value, it is determined that the pressure loss of an intake and exhaust system has changed. If it is determined that the pressure loss of an intake and exhaust system has changed, EGR is inhibited, and if not so, EGR is permitted to be performed. These threshold values are varied depending on a target EGR rate.

This engine includes an EGR device. The engine is provided with: an EGR gas temperature sensor; an EGR valve; an EGR control unit; an EGR valve position detection unit; a diagnosis unit; a first timer; a second timer; and a diagnosis control unit. The diagnosis unit diagnoses whether the EGR gas temperature sensor has failed, on the basis of a detected value from the EGR gas temperature sensor. The first timer, when the EGR valve is open, performs counting in accordance with the passage of time. The second timer, if a count value of the first timer is greater than or equal to a first threshold value set in advance, and if a predetermined condition is satisfied, performs counting in accordance with the passage of time. The diagnosis control unit prohibits diagnosis by the diagnosis unit if a count value of the second timer is less than a second threshold value set in advance, and permits the diagnosis if the count value is greater than or equal to the second threshold value.

This engine includes an EGR device. The engine is provided with: an EGR gas temperature sensor; an EGR valve; an EGR control unit; an EGR valve position detection unit; a diagnosis unit; a first timer; a second timer; and a diagnosis control unit. The diagnosis unit diagnoses whether the EGR gas temperature sensor has failed, on the basis of a detected value from the EGR gas temperature sensor. The first timer, when the EGR valve is open, performs counting in accordance with the passage of time. The second timer, if a count value of the first timer is greater than or equal to a first threshold value set in advance, and if a predetermined condition is satisfied, performs counting in accordance with the passage of time. The diagnosis control unit prohibits diagnosis by the diagnosis unit if a count value of the second timer is less than a second threshold value set in advance, and permits the diagnosis if the count value is greater than or equal to the second threshold value.

The control apparatus for a compression ignition type engine includes a plurality of cylinder inner pressure sensors that detect pressure in each cylinder, and a combustion control unit. The combustion control unit corrects a target fuel injection amount of each cylinder by an injector based on a deviation between a predicted combustion period that is a period from an ignition timing by an ignition plug to a predetermined mass combustion timing and that is obtained based on a preset combustion model, and an actual combustion period that is a period from the ignition timing by the ignition plug to an actual combustion timing and that is obtained based on cylinder inner pressure, such that the period from the ignition timing by the ignition plug to the predetermined mass combustion timing, which is the timing when fuel having a predetermined mass ratio combusts, is equalized in each cylinder.

The control apparatus for a compression ignition type engine includes a plurality of cylinder inner pressure sensors that detect pressure in each cylinder, and a combustion control unit. The combustion control unit corrects a target fuel injection amount of each cylinder by an injector based on a deviation between a predicted combustion period that is a period from an ignition timing by an ignition plug to a predetermined mass combustion timing and that is obtained based on a preset combustion model, and an actual combustion period that is a period from the ignition timing by the ignition plug to an actual combustion timing and that is obtained based on cylinder inner pressure, such that the period from the ignition timing by the ignition plug to the predetermined mass combustion timing, which is the timing when fuel having a predetermined mass ratio combusts, is equalized in each cylinder.

A turbine bypass valve comprising: a casing defining first and second casing ports; and a valve cartridge mounted to the casing; wherein the valve cartridge comprises: first and second valve ports; and a valve member, the valve member being movable between a first position in which there is a flow path between the first and second valve ports, and a second position in which the valve member substantially blocks said flow path between the first and second valve ports; and wherein the valve cartridge is mounted to the casing such that the first valve port is aligned with the first casing port, and the second valve port is aligned with the second casing port.

A hybrid vehicle includes an engine, an exhaust gas recirculation device, a traveling motor, and a control device. The exhaust gas recirculation device includes a communication pipe that allows an exhaust pipe and an intake pipe of the engine to communicate with each other and a valve that is provided in the communication pipe. The control device is configured to perform foreign matter removal control for opening and closing the valve when foreign matter caught in the valve is detected and the hybrid vehicle stops.