Methods and systems are provided for controlling a turbocharged engine. In one arrangement, a method may include concurrently adjusting an exhaust recirculation gas flow and a turbine flow while adjusting geometry of a compressor to compensate for disturbance caused by the compressor adjustment.

A combustion engine for a vehicle has an intake duct through which a fuel gas/air/exhaust gas mixture can be fed to a combustion unit of the combustion engine, and an exhaust gas recirculation system feeding in an exhaust gas from the combustion unit at an exhaust gas admission region to the gas fed to the combustion unit. A measuring device that determines the fuel gas/air/exhaust gas mass flow and the fuel gas/air/exhaust gas temperature is arranged in the intake duct upstream of the combustion unit and downstream of the exhaust gas admission region. A temperature sensor is arranged both in the exhaust gas recirculation system and in the intake duct, in each case upstream of the exhaust gas admission region, in addition to the measuring device, to determine a recirculated exhaust gas mass flow and/or an air mass flow fed to the combustion unit.

In a control device of an internal-combustion engine according to the disclosure, an intake throttle valve (25) for adjusting an EGR valve differential pressure (PEGR) is provided, an EGR valve upstream pressure (PEGR0) is estimated by using a target fresh air amount (GAIRCMD) (step 6), a target differential pressure (PEGRCMD) is set to a smaller value as the target fresh air amount (GAIRCMD) becomes smaller (FIG. 5), and a difference between the EGR valve upstream pressure (PEGR0) and the target differential pressure (PEGRCMD) is set as a target valve downstream pressure (P1CMD) (step 7). By using the target fresh air amount (GAIRCMD), the EGR valve upstream pressure (PEGR0), and the target valve downstream pressure (P1CMD), the target EGR valve opening degree (LEGRCMD) is set (step 23), and an EGR valve (43) is controlled based on the target EGR valve opening degree (step 24).

An internal combustion engine includes an intercooler configured to cool an intake gas compressed by a compressor, a cooler bypass passage configured to bypass the intercooler, and a cooler bypass valve configured to open and close the cooler bypass passage, and an exhaust gas recirculation gas is introduced into an upstream side of the intercooler. An electronic control unit is configured to open the cooler bypass valve during use of a high exhaust gas recirculation rate region, and to close the cooler bypass valve during use of a low exhaust gas recirculation rate region.

Methods and systems are provided for operating an electric assisted turbocharger. In one example, a method may include adjusting a position of a turbine of the turbocharger responsive to a level of a power deficiency, and operating an electric motor of the turbocharger based on the power deficiency.

Methods and systems are provided for measuring exhaust gas recirculation (EGR) distribution among individual engine cylinders. In one example, a method may include fluidly coupling a plurality of intake runners of an engine to a vacuum pump, diverting a portion of intake charge gas from the intake runner to a gas composition sensor with the vacuum pump, measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration.

Atomic oxygen is provided for the purpose of promoting reliable ignition and smooth combustion in a spark ignition internal combustion engine is to disperse a low concentration of an atomic oxygen precursor, such as nitrous oxide (N.sub.2O), into the flammable mixture of air and gasoline vapor prior to the time of ignition. The introduction of N.sub.2O may take place in the intake manifold, in the stream of exhaust gas being returned as part of the EGR process, or directly into the combustion chamber (for example through a small orifice in the base of the spark plug or through a small nozzle located elsewhere in the cylinder head). Introduction of N.sub.2O directly into the combustion chamber may be continuous, or it may be pulsed so as to occur at the time of, or shortly before, spark ignition.

Methods and systems for providing exhaust gas recirculation to a two stroke opposed piston diesel engine are described. In one example, high and low pressure exhaust gas recirculation systems may be activated or deactivated in response to exhaust gas hydrocarbon concentration and particulate matter flow rate from the engine. In addition, operation of the low and high pressure exhaust gas recirculation systems may be responsive to an operating state of a supercharger compressor.

Methods and systems are provided for improving fuel usage while addressing knock by adjusting the use of spark retard and direct injection of a fluid based on engine operating conditions and the composition of the injected fluid. One or more engine parameters, such as EGR, VCT, boost, throttle position, are coordinated with the direct injection to reduce torque and EGR transients.

Methods and systems are provided for cleaning an exhaust particulate filter by routing air via the exhaust particulate filter during a vehicle-off condition. In one example, during vehicle-off conditions, a turbocharger may be reverse rotated via an electric motor or an engine may be reverse rotated via an electric machine to route air via the exhaust particulate filter and the soot collected from the particulate filter may then be deposited on an air filter coupled to the intake manifold. During a subsequent engine start, the soot from the intake air filter may be routed to the engine cylinders for combustion.