Systems and methods for controlling fuel factions delivered to different cylinders are provided. In one example, a controller is configured to, during a single engine cycle and responsive to a first condition, deliver a lower fraction of a first fuel into a donor cylinder in comparison to a fraction of the first fuel being injected into a non-donor cylinder and deliver a higher fraction of a second fuel into the donor cylinder in comparison to a fraction of the second fuel being injected into the non-donor cylinder.

Methods and systems are provided for exhaust gas heat recovery at a split 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. Warm 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.

A system and method for preventing a failure of an exhaust heat recovery device are provided. The method includes operating a sole exhaust heat recovery mode when cooling water has a temperature less than a warm-up reference temperature to introduce all exhaust gas flowing from a DPF into the exhaust heat recovery device where the exhaust gas exchanges heat with the cooling water. Additionally, a passage through which the exhaust gas bypasses the exhaust heat recovery device is opened when the exhaust gas at a rear of the DPF has a temperature greater than the warm-up reference temperature during the sole exhaust heat recovery mode.

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.

Starting an internal combustion engine may be difficult as a consequence of the operating conditions of the engine. Even after the engine has started, it may take a long period of time for the engine to reach operating temperatures. In the present disclosure, when engine start difficulty is expected, before starting the engine a forced induction compressor arranged with the engine may be turned on to increase the engine intake air pressure before the engine is started.

A system and method for providing torque-assist to a rotary shaft of an internal combustion engine control an electric machine in response to operation of an exhaust gas recirculation (EGR) valve to assist the rotation of the rotary shaft. The system and method facilitate periodic operation of the EGR valve to purge condensation without objectionable torque reduction when the engine is operating near full load.

Methods and systems are provided for using compression heating to heat a cylinder piston before cylinder combustion is resumed. Cylinder heating is achieved using combinations of slow unfueled engine rotation where the engine cylinders are heated via compression stroke heating, and slow compressor rotation where the cylinders are heated via compression heating. One or more intake or exhaust heaters may be concurrently operated to expedite cylinder heating.

In cases where an EGR device is provided in which an EGR gas is recirculated to an upstream side of a compressor, the generation of condensed water is suppressed in an intake passage at the downstream side of the compressor. In the case where the temperature of a wall surface of the intake passage estimated or detected by a temperature detector is equal to or less than a predetermined temperature, a rotational speed of a turbine is made higher than in the case where the estimated or detected temperature of the wall surface of the intake passage is higher than the predetermined temperature, and torque of an internal combustion engine is adjusted such that an amount of change in an output of the internal combustion engine at the time of the rotational speed of the turbine being thus made higher falls within a predetermined range.

The invention relates to a control method that allows the mean quantity of nitrogen oxides per kilometer covered emitted by a vehicle fitted with an internal combustion engine associated with a post-treatment system to be kept below a predefined fixed threshold, for any journey made by the vehicle. The mean quantity emitted over a fixed elementary distance that has just been covered by the vehicle is calculated iteratively, together with a long-term conformity factor which is equal to the mean quantity emitted over the entire distance covered since the start of the journey. When it is found that the long-term conformity factor is above the threshold, the engine and/or the post-treatment system is regulated in such a way as to obtain, over the next fixed elementary distance, a mean quantity of nitrogen oxides per kilometer that is lower than the threshold value FC, for example equal to 90% of the threshold, whatever the engine operating point. Thus, the long-term conformity factor converges towards the threshold.

A computer control network is connected to a multiple-cylinder engine and implements aftertreatment temperature management. Processors are configured to determine an aftertreatment temperature-efficient air to fuel ratio that satisfies the sensed power output request, determine an air to fuel ratio adjustment, select an in-cylinder exhaust gas recirculation technique, select at least one EGR cylinder of the multiple-cylinder engine to implement the in-cylinder exhaust gas recirculation technique, and control the intake valves to open and the exhaust valves to close for the selected at least one EGR cylinder to adjust the oxygen and particulate content of the exhaust gas by applying at least a second compression stroke of the respective reciprocating piston of the at least one EGR cylinder to the exhaust gas to push the exhaust gas through to the intake manifold.