Abstract: A compression-ignition engine (10) comprises an exhaust system (16) with an exhaust gas after-treatment assembly, the after-treatment assembly comprising a three-way catalyst device (30) and an SCR device (34), the three-way catalyst device being arranged upstream the SCR device in close-coupled position with respect to the engine. An engine control unit (47) is provided for controlling operation of the engine. The engine control unit is configured to monitor the temperature of the SCR device and to control the engine to change over from an operation with a lean air/fuel mixture to an operation with a stoichiometric or a rich air/fuel mixture in response to the temperature of the SCR device dropping below a temperature threshold.

Abstract: A compression-ignition internal combustion engine system having an exhaust passage and an exhaust gas treatment arrangement, wherein the exhaust gas treatment arrangement comprises a three-way catalytic converter.

Abstract: A compression-ignition engine (10) comprises an exhaust system (16) with an exhaust gas after-treatment assembly, the after-treatment assembly comprising a three-way catalyst device (30) and an SCR device (34), the three-way catalyst device being arranged upstream the SCR device in close-coupled position with respect to the engine. An engine control unit (47) is provided for controlling operation of the engine. The engine control unit is configured to monitor the temperature of the SCR device and to control the engine to change over from an operation with a lean air/fuel mixture to an operation with a stoichiometric or a rich air/fuel mixture in response to the temperature of the SCR device dropping below a temperature threshold.

Abstract: A compression-ignition internal combustion engine system having an exhaust passage and an exhaust gas treatment arrangement, wherein the exhaust gas treatment arrangement comprises a three-way catalytic converter.

Abstract: It relates to a method of operating a compression ignition engine comprising:— determining an instantaneous driver torque demand; selectively operating the engine in a first mode or a second mode dependent on the rate of change of driver torque demand; said first mode comprising an air lead mode whereby the intake air flow rate is controlled to achieve the instantaneous driver torque demand and an amount of fuel injected is controlled to obtain a target air/fuel ratio based upon said intake air flow rate; said second mode comprising a fuel lead mode wherein the amount of fuel injected is controlled to achieve the instantaneous torque demand.

Abstract: It relates to a method of operating a compression ignition engine comprising:— determining an instantaneous driver torque demand; selectively operating the engine in a first mode or a second mode dependent on the rate of change of driver torque demand; said first mode comprising an air lead mode whereby the intake air flow rate is controlled to achieve the instantaneous driver torque demand and an amount of fuel injected is controlled to obtain a target air/fuel ratio based upon said intake air flow rate; said second mode comprising a fuel lead mode wherein the amount of fuel injected is controlled to achieve the instantaneous torque demand.

Abstract: A method is specified for controlling a combustion engine in a motor vehicle, namely for optimally adjusting an air/fuel ratio which is distinguished in that the air/fuel ratio is the result of a regulation process. Individual aspects of the invention further address a regulation method particularly suitable for such regulation in consideration of the available input values and readings. For the purposes of supporting regulation, an adaptation method is specified which can also be used independently of the regulation method or with other regulation methods and which enables the regulation to be continuously adapted to the respective operating conditions, such as, for example, the engine operational performance, and signs of wear and tear and disruptions due to deposits etc. which accompany it.

Abstract: A method for engine control in a motor vehicle is specified, in particular a method for controlling a combustion engine in a motor vehicle, namely for optimally adjusting a quantity of exhaust gas, which is recirculated, in an exhaust gas recirculation branch, from an exhaust manifold situated after the engine on the output side to an intake manifold situated before the engine on the input side, and a device functioning according to the method, which enables controlling and, where applicable, regulation of the recirculated exhaust gas quantity, whereby the regulation, in a preferred embodiment of the invention, is supplemented with possibilities for parameter adaptation.

Abstract: An improved method of dynamically estimating the concentration of recirculated exhaust gases in air/fuel mixture of an internal combustion engine equipped with an exhaust gas recirculation (EGR) system. The EGR concentration at engine intake ports is separately estimated with static and dynamic models, and the EGR concentration for control purposes is determined by adjusting the result of the dynamic model based on a deviation of the dynamic model from the static model. This method provides the total EGR concentration, but can alternatively provide the inert EGR concentration through the inclusion of an exhaust inert ratio model.

Abstract: An improved method of dynamically estimating the concentration of recirculated exhaust gases in air/fuel mixture of an internal combustion engine equipped with an exhaust gas recirculation (EGR) system. The EGR concentration at engine intake ports is separately estimated with static and dynamic models, and the EGR concentration for control purposes is determined by adjusting the result of the dynamic model based on a deviation of the dynamic model from the static model. This method provides the total EGR concentration, but can alternatively provide the inert EGR concentration through the inclusion of an exhaust inert ratio model.

Abstract: A method of improving the operating characteristics of an internal combustion engine equipped with electronic throttle control employs variable cam timing to vary the phasing of the intake valves and/or exhaust valves so as to achieve lower feed gas emissions and improved fuel economy while delivering as closely as possible the desired torque. The method can be implemented using a fuel-lead strategy or an air-lead strategy. Whenever a change is requested in the amount of torque, the method responds by adjusting the amount of fuel flow, the spark timing, the position of the throttle and/or the positions of the intake valves and/or the exhaust valves so as to deliver the desired torque. The method adjusts those operating parameters in a way that improves the ability of the engine to deliver the desired torque, produce less feed gas emissions, idle more stably, and consume less fuel.

Abstract: A method for controlling a power supply for a vehicle engine utilizes two sensors monitoring a power supply control member. In the event of a disturbance of the one of the sensor signals, the other sensor signal is used for determining the actuator control signals. If such other sensor signal exceeds a limit value, the actuator control signals are determined by a proportional-plus integral control, with the integral portion of the control being based on an operating state of the vehicle when the limit value is exceeded.