Abstract: Methods and systems are provided for integrating a VCR engine with a CVT transmission. Responsive to a driver demand, a controller may determine whether to maintain a current compression ratio or transition to an alternate compression ratio based on the fuel economy benefit of the transition and further based on any engine limitations that may be incurred at the engine speed-load following the transition. To improve the net fuel economy benefit while addressing the engine limitation, a compression ratio transition may be combined with a CVT adjusted engine speed-load regime, while maintaining engine power output.

Abstract: 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.

Abstract: Methods and systems are provided for synergizing the benefits of an engine exhaust driven fuel reformer in a hybrid vehicle system. A vehicle controller may hold the engine in a narrow operating range where fuel reformer operation is optimal while using motor and/or CVT adjustments to address transients generated as driver demand varies. The controller may also adjust an operating range of temperatures of the reformer to enable extended fuel reforming even after the engine of the hybrid has been shutdown.

Abstract: Methods and systems are provided for integrating a bi-fuel engine with a CVT transmission. Responsive to a driver demand, a controller may determine whether to maintain usage of a current fuel or transition to an alternate fuel based on the cost efficiency of the transition and further based on any engine limitations that may be incurred at the engine speed-load following the transition. To improve the net fuel economy benefit while addressing the engine limitation, a fuel transition may be combined with a CVT adjusted engine speed-load regime, while maintaining engine power output.

Abstract: Method and systems are provided for, in response to a state of charge (SOC) of a vehicle battery increasing above a threshold SOC, reducing an alternator charging based on one or more of a spark timing, an engine speed, an air-fuel ratio, and an engine load. In this way, fuel consumption may be reduced while maintaining a battery SOC for operation of front-end accessories may be achieved, and fuel consumption may be reduced during aggressive vehicle driving conditions such has high engine loads near transmission downshift thresholds and high engine speeds.

Abstract: Methods and systems are provided for controlling hybrid vehicle engine operation, where the vehicle engine comprises one or more cylinders dedicated to recirculating exhaust to an intake manifold. In one example, during an engine cold-start event or other event where temperature of one or more exhaust catalysts are below a temperature needed for catalytic activity, fuel injection to the dedicated exhaust gas recirculation cylinder(s) is maintained shut off, while its intake and exhaust valves are maintained activated, thus enabling the dedicated exhaust gas recirculation cylinder(s) to route air to the intake manifold of the engine, resulting in exhaust gas lean of stoichiometry that may serve to heat the catalyst. In this way, during cold start events and other events where temperature of one or more exhaust catalysts are below a temperature for catalytic activity, combustion stability issues may be avoided, and exhaust catalyst(s) rapidly heated, thereby reducing undesired tailpipe emissions.

Abstract: Methods and systems are provided for controlling engine operation in a hybrid vehicle, where the vehicle engine comprises one or more cylinders dedicated to recirculating exhaust to the intake manifold. In one example, if an engine load decreases below a level where dedicated exhaust gas recirculation may lead to combustion stability issues, engine load may be increased above the demanded load and the excess power used to charge a system battery, or if the battery state of charge is above a threshold, the engine may be shut down and the vehicle propelled via battery power. In this way, fuel economy and combustion stability issues may be improved, NOx emissions reduced, and costs for implementation of dedicated exhaust gas recirculation decreased.

Abstract: A vehicle is provided. The vehicle includes an engine, an electric machine, an electric heater, and a controller. The electric machine is configured to recharge a battery through regenerative braking. The electric heater is configured to heat an engine coolant. The controller is programmed to redirect regenerative braking power to the electric heater in response to the engine coolant temperature being below a threshold.

Abstract: Methods and systems are provided for synergizing the benefits of an electric fuel separator in a hybrid vehicle system. A vehicle controller may hold the engine in a narrow operating range where usage of a selected higher octane or lower octane fuel fraction is optimal while using motor and/or CVT adjustments to address transients generated as driver demand varies. The controller may also adjust a fuel separator speed/pressure opportunistically during regenerative braking to maximize electrical usage as well as at low load conditions to enable extended engine operation in a more fuel efficient load region.

Abstract: Systems and methods for improving engine torque response are presented. In one example, engine idle speed is increased to shorten engine torque response based on engine operating conditions. The methods and systems may be useful for operating an engine that is supplied a gaseous fuel.

Abstract: Methods and systems are provided for controlling and coordinating control of a post-catalyst exhaust throttle and an EGR valve to expedite catalyst heating. By closing both valves during an engine cold start, an elevated exhaust backpressure and increased heat rejection at an EGR cooler can be synergistically used to warm each of an engine and an exhaust catalyst. The valves may also be controlled to vary an amount of exhaust flowing through an exhaust venturi so as to meet engine vacuum needs while providing a desired amount of engine EGR.

Abstract: Methods and systems are provided for adjusting a throttle during deceleration fuel shut off (DFSO). In one example, a method may comprise controlling a position of a throttle in an air inlet of an engine propelling a vehicle, in relation to vehicle operator commands, and during a deceleration fuel shut off mode, increasing opening of said throttle independently of said operator commands when speed of said vehicle is or is expected to fall below a desired speed or desired speed trajectory.

Abstract: A vehicle powertrain includes an engine driven variable displacement pump and an accumulator. A switch network controls the flow of fluid among the pump, the accumulator, a line pressure circuit of a valve body, and the sump, enabling several operating modes. In a balanced operating mode, no fluid flows into or out of the accumulator. In a discharging mode, fluid flows from the accumulator reducing the power required by the pump to increase output torque or reduce fuel consumption. In a charging mode, fluid flows into the accumulator for later use. Fluid also flow into the accumulator in a high-torque mode in which the pump and switch network are set to intentionally increase the pump torque to assist in deceleration.

Abstract: An engine system and method for improving sampling of a port throttle pressure sensor. In one example, the port throttle pressure sensor is sampled a plurality of times during a cylinder cycle and different engine operating conditions are determined from selected samples. The system and method may improve engine air-fuel control as well as engine diagnostics.

Abstract: Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

Abstract: A hybrid vehicle includes an exhaust turbine disposed in an exhaust path coupled to an electric machine and a compressor for an air-conditioning system. The vehicle includes a controller that controls the electric machine based on a difference between the power demand of the compressor and the power generated by the exhaust turbine. The electric machine may operate as a motor or a generator based on the difference. The vehicle may include a first clutch coupled to the electric machine and the compressor. The vehicle may include a second clutch coupled between the exhaust turbine and the electric machine. The controller may control the clutches based on the power demand and the power generated.

Abstract: Methods and systems are provided for the estimation of an aircharge into a cylinder used to adjust an engine operating parameter, based on a manifold pressure signal stored in a buffer. In one example, a method may include sampling an intake manifold pressure sensor signal at even increments of time, stamping it with its corresponding crank angle and storing it in a buffer. The closest stored signal to the intake valve closing of a cylinder may be used to calculate its aircharge.

Abstract: Methods and systems are provided for reducing torque transients experienced when a dedicated EGR cylinder is transitioned in to or out of dedicated EGR mode. During a transition, each of an intake throttle and a wastegate is adjusted in opposing directions. Throttle and wastegate adjustments are coordinated with adjustments to spark timing and intake cam timing to provide sufficient torque reserve for the transition.

Abstract: Methods are provided for controlling an engine. One method may include boosting engine intake air to a cylinder; and injecting an amount of a scavenging fluid into the cylinder based on an amount of cylinder residual exhaust gas. A scavenging fluid, such as water or windshield washer fluid evaporates on contact with the hot exhaust gases and hot metal components and the expanded volume of the vapor displaces the residual exhaust gas, thereby improving engine scavenging.

Abstract: Systems and methods for separating higher octane fuel from a fuel mixture are presented. In one example, higher octane fuel is separated from lower octane fuel and allowed to condense in a fuel tank holding higher octane fuel so that parasitic engine losses are not increased by having to separate higher octane fuel from lower octane fuel a second time. The approach may be applied to fuel systems that include multiple fuel tanks storing different types of fuel.