Conventional APUs for diesel-electric locomotives may include an AC electric generator and typically require additional hardware to be installed to convert the AC power output by the generator to DC power that can power electrical systems or charge batteries in the locomotive. According to some embodiments, there is provided an auxiliary power unit (APU) or system for operation in cooperation with a primary engine. The APU includes a secondary engine; a primary engine coolant heating system, or a primary engine lubricant heating system; a control system that automatically shuts down the primary engine and starts the secondary engine responsive to a predetermined condition; and a Direct Current (DC) power generator that generates an output voltage, the DC power generator being driven by the secondary engine.

A method includes: (a) determining an engine speed of an internal combustion engine, wherein the internal combustion engine has an engine wall, and the engine wall has a wall temperature; (b) determining an engine load of the internal combustion engine; (c) determining a wall-reference temperature as a function of the engine load and the engine speed of the internal combustion engine; and (d) adjusting, using a cooling system, a volumetric flow rate of a coolant flowing through the internal combustion engine to maintain the wall temperature at the wall-reference temperature.

A method includes: (a) determining an engine speed of an internal combustion engine, wherein the internal combustion engine has an engine wall, and the engine wall has a wall temperature; (b) determining an engine load of the internal combustion engine; (c) determining a wall-reference temperature as a function of the engine load and the engine speed of the internal combustion engine; and (d) adjusting, using a cooling system, a volumetric flow rate of a coolant flowing through the internal combustion engine to maintain the wall temperature at the wall-reference temperature.

The present invention relates to a method (100) for cold start optimization of an internal combustion engine (10) comprising: determining (110) a start of an engine preheating device (12); transmitting (115) a selected coolant temperature T.sub.cool_trans to an engine control unit (14); and adapting (140) the selected coolant temperature T.sub.cool_trans transmitted to the engine control unit (14) to a current coolant temperature T.sub.coll_current during a time interval Δt following the start of the internal combustion engine (10). The present invention further relates to an auxiliary control unit (22) which is configured to execute the method (100).

The present invention relates to a method (100) for cold start optimization of an internal combustion engine (10) comprising: determining (110) a start of an engine preheating device (12); transmitting (115) a selected coolant temperature T.sub.cool_trans to an engine control unit (14); and adapting (140) the selected coolant temperature T.sub.cool_trans transmitted to the engine control unit (14) to a current coolant temperature T.sub.coll_current during a time interval Δt following the start of the internal combustion engine (10). The present invention further relates to an auxiliary control unit (22) which is configured to execute the method (100).

A method includes: (a) determining an engine speed of an internal combustion engine, wherein the internal combustion engine has an engine wall, and the engine wall has a wall temperature; (b) determining an engine load of the internal combustion engine; (c) determining a wall-reference temperature as a function of the engine load and the engine speed of the internal combustion engine; and (d) adjusting, using a cooling system, a volumetric flow rate of a coolant flowing through the internal combustion engine to maintain the wall temperature at the wall-reference temperature.

A combined engine system is disclosed which may help to meet electrical power demand of a common load that can vary in an unpredictable manner. The system comprises at least one primary engine and one or more secondary engines. An after-treatment system is connected to the engines to receive exhaust flow from each of the engines. A controller is configured to operate the system in a first operating mode when only the primary engine is running and a second operating mode when the secondary engines are run together with the primary engine. Exhaust flows from each of the engines are passed through the after-treatment system which allows the after-treatment system to be heated by the exhaust flow of the primary engine before receiving exhaust flows from the secondary engines.

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.

A coolant heater for a vehicle includes: a housing unit having an inlet part through which a coolant is introduced and an outlet part through which the coolant is discharged; a baffle assembly provided in an internal space of the housing unit and having a first flow path through which the coolant flows in a first direction and a second flow path through which the coolant, passing through the first flow path, flows in a second direction different from the first direction; a first heater part provided in the first flow path; and a second heater part provided in the second flow path. The coolant heater makes it possible to obtain an advantageous effect of improving a fast-acting heating performance and heating efficiency.

A method of providing coolant to an electric battery for powering a drive train of an electric vehicle is provided. The method includes providing coolant from a coolant source off-board the electric vehicle at a first rate to cool the electric battery during recharging of the electric battery; and circulating coolant through a coolant loop on-board the electric vehicle at a second rate less than the first rate to cool the electric battery after the recharging of the electric battery.