Methods and systems are provided for synergizing the benefits of a variable compression ratio engine in a hybrid vehicle system. A vehicle controller may hold the engine in a lower compression ratio during engine pull-ups and pull-downs, in particular when passing through a low speed region where compression bobbles can occur. During engine operation, in response to a change in driver demand, the controller may opt to switch the compression ratio or maintain a current compression ratio while smoothing a torque deficit using motor torque, the selection based on fuel economy.

A control system for a hybrid vehicle configured to avoid unintentional reduction in a driving force is provided. The control system is configured to estimate a vehicle speed after a predetermined period of time during propulsion of the vehicle under single-motor mode, and to shift the operating mode directly from the single-motor mode to an engine mode while skipping a dual-motor mode, if a current operating point of the vehicle enters into an operating region where both of the second mode and the third mode are available but the operating mode is expected to be further shifted to the engine mode.

A vehicle and method for controlling a vehicle having a variable displacement engine with an auxiliary machine connected directly to the engine crankshaft and to an energy storage device includes switching from a cylinder disablement (VDE) mode to a normal mode when the torque demand and engine speed lie outside an outer range defined by a first threshold (T.sub.out), and switching from the normal mode to the VDE mode when the torque demand and engine speed lie within an inner range, which lies within the outer range and defined by a second threshold (T.sub.in). When operating in a band between the two thresholds, the auxiliary machine draws energy from the energy storage device and supplements the output torque from the engine if operating in the VDE mode, and derives torque from the engine crankshaft to recharge the energy storage device if operating in the normal mode.

A drive system for a vehicle having a rear drive assembly powered by a first power source, a front drive assembly in selective electrical communication with a second power source, a selector switch to selectively permit or prevent electrical communication between the front drive assembly and the second power source, and an output capacity sensor to detect an output of the first power source, where the rear drive assembly drives the vehicle when the selector switch is in a first position and both the rear and front drive assemblies drive the vehicle when the selector switch is in a second position and the output capacity sensor detects that the output of the first power source meets a threshold output.

In one aspect the present subject matter is directed to a gas-electric propulsion system for an aircraft. The system may include a turbofan jet engine, an electric powered boundary layer ingestion fan that is coupled to a fuselage portion of the aircraft aft of the turbofan jet engine, and an electric generator that is electronically coupled to the turbofan jet engine and to the boundary layer ingestion fan. The electric generator converts rotational energy from the turbofan jet engine to electrical energy and provides at least a portion of the electrical energy to the boundary layer ingestion fan. In another aspect of the present subject matter, a method for propelling an aircraft via the gas-electric propulsion system is disclosed.

In one aspect the present subject matter is directed to a gas-electric propulsion system for an aircraft. The system may include a turbofan jet engine, an electric powered boundary layer ingestion fan that is coupled to a fuselage portion of the aircraft aft of the turbofan jet engine, and an electric generator that is electronically coupled to the turbofan jet engine and to the boundary layer ingestion fan. The electric generator converts rotational energy from the turbofan jet engine to electrical energy and provides at least a portion of the electrical energy to the boundary layer ingestion fan. In another aspect of the present subject matter, a method for propelling an aircraft via the gas-electric propulsion system is disclosed.

A drive train (10) for driving a motor vehicle has a combustion engine (12) for providing purely mechanical drive for the motor vehicle. A transmission (16) can be coupled to the combustion engine (12) via a shaft unit (14) for transmitting torque between the motor vehicle transmission (16) and the combustion engine (12). A reserve volume (18) is between the combustion engine (12) and the motor vehicle transmission (16) and is penetrated by the shaft unit (14). The reserve volume (18) can accommodate a high-voltage electric machine for purely electric drive of the motor vehicle or a low-voltage electric machine (32) for applying an electrically generated assistance torque to the motor vehicle transmission (16). As a result, a hybrid functionality can be made available to an at least limited degree, with the result that a cost-effective drive train (10) configured for a hybrid motor vehicle is made possible.

Methods and systems are provided for controlling a vehicle engine to adjust exhaust warm-up strategy based on a vehicle network information. In one example, in response to an expected decrease in temperature of a catalyst of a vehicle below a threshold and an estimated duration thereof based on communications external from the vehicle, a method may include delaying catalyst heating actions, when the catalyst heating actions are determined to be unable to heat up the catalyst to threshold temperatures. However, the catalyst heating actions may be enabled when the catalyst heating actions are determined to be able to achieve the threshold temperature within the duration.

Methods and systems are provided for conducting vehicle fuel system and/or evaporative emissions system diagnostics, where the diagnostics rely on a positive pressure with respect to atmospheric pressure. In one example, a method comprises activating an electric compressor positioned in an intake of an engine configured to receive purge gasses from the evaporative emissions system under boosted engine operation and natural engine operation, to direct a positive pressure with respect to atmospheric pressure to the fuel system and/or evaporative emission system to conduct said diagnostic. In this way, diagnostics that rely on positive pressure with respect to atmospheric pressure may be conducted in vehicles with a dual-path purge system, without introduction of a pump in the evaporative emissions system.

The present disclosure provides an engine stop/start control system for a vehicle comprising a first engine restart module configured to set a restart frequency and duration of an engine in response to a sensed ambient temperature, a second engine restart module configured to control the engine in response to a sensed characteristic temperature associated with the engine, a third engine restart module configured to control the engine in response to occurrence or non-occurrence of at least one expected charging event along a predefined route, a fourth engine restart module configured to control the engine in response to a state-of-charge of an energy storage device, and a route optimization module configured to set and adjust a proposed route to a destination that results in reduced engine usage.