A control device for a hybrid vehicle calculates a required drive force based on an accelerator position. The control device also calculates a required torque of the engine based on the required drive force. The control device further calculates a target torque for the engine by subjecting the required torque to a gradual change process for lessening a change in a value and performs an engine control such that an engine torque becomes equal to the target torque. The control device also performs a torque control on the motor such that a drive force of the hybrid vehicle becomes equal to the required drive force in a state in which the engine torque is equal to the target torque.

A propulsion system, control system, and method are provided for optimizing fuel economy, which use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values based on weighting values, a plurality of predicted values, and a plurality of requested values. The set of possible command values having the lowest cost is determined. A linearized axle torque requested value and a linearized axle torque measured value are each created by subtracting an estimated disturbance. The estimated disturbance is determined based on a model of a relationship between measured engine output torque and measured transmission ratio. The linearized axle torque measured value is used to compute the predicted values, which are used to determine the cost. The linearized axle torque requested value is also used to determine the cost.

Systems and methods to reduce operating expenses of a vehicle based on control of operation of a vehicle system. The system includes a controller. The controller is structured to receive one or more parameters comprising expense data, adjust operating expenses of a vehicle system based on the one or more parameters, and generate a command structured to adjust operation of the vehicle system responsive to the adjustment of the operating expenses.

Methods and systems are provided for controlling vehicle torque output during cruise control. In one example, a method may include determining future vehicle torque output by minimizing an objective function based on an instantaneous vehicle speed, an average vehicle speed, and a present vehicle torque output. The weights of the objective function may be updated based on the past and the present vehicle operating parameters.

An engine start-stop control method and device for a hybrid electric vehicle, and a hybrid electric vehicle belong to the technical field of vehicles. The method includes: obtaining a target parameter or a target signal, which is engine start-stop related, of the hybrid electric vehicle; determining, according to the target parameter or target signal, whether an engine start-stop related event occurs; if so, determining a level of the engine start-stop related event; and performing engine start-stop control according to the engine start-stop related event and the level thereof; wherein the engine start-stop related event includes at least one of the following: an energy management related start-stop event, a driving behavior related start-stop event, an engine state related start-stop event, an external controller request start-stop event, and other condition related start-stop events. The operating efficiency of the vehicle and the user experience are improved.

The vehicle behavior control device comprises an engine control part operable, when an steering speed is greater than a predetermined threshold, and both of a steering wheel angle of a vehicle and the steering speed are increasing, to reduce an output torque of a multi-cylinder internal combustion engine along with an increase in the steering speed, and when the steering speed is equal to or less than the threshold, to stop the reduction of the output torque, and a threshold setting part operable, when the operation mode of the engine is the all-cylinder operation, to set the threshold to a first threshold T.sub.S1, and, when the operation mode of the engine is the reduced-cylinder operation, to set the threshold to a second threshold T.sub.S2 which is less than the first threshold T.sub.S1.

A propulsion system, control system, and method are provided for optimizing fuel economy, which use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values based on weighting values, a plurality of predicted values, and a plurality of requested values. The set of possible command values having the lowest cost is determined. A linearized axle torque requested value and a linearized axle torque measured value are each created by subtracting an estimated disturbance. The estimated disturbance is determined based on a model of a relationship between measured engine output torque and measured transmission ratio. The linearized axle torque measured value is used to compute the predicted values, which are used to determine the cost. The linearized axle torque requested value is also used to determine the cost.

A propulsion system, control system, and method are provided for optimizing fuel economy, which use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values of based on a first predetermined weighting value, a second predetermined weighting value, a plurality of predicted values, and a plurality of requested values. The set of possible command values having the lowest cost is determined and defined as a set of selected command values. Fuel is minimized by minimizing engine power for a requested axle power. Accordingly, a fuel consumption rate requested value is determined based on an air-per-cylinder (APC) requested value.

A vehicle control system is provided to promptly execute an ignition retard of the engine during shifting a gear stage in such a manner as to prevent an engine misfire, while switching air/fuel ratio from lean-burn ratio to stoichiometric ratio. An air/fuel ratio is switched between a stoichiometric ratio and a lean-burn ratio based on an operating point of an engine determined based on an engine speed and an engine torque. If a shifting operation of gear stage and a switching operation of the air/fuel ratio from the lean-burn ratio to the stoichiometric ratio are expected to be executed simultaneously, a controller delays the shifting operation of gear stage until completion of the switching operation of the air/fuel ratio.

When a temperature of a catalyst in an exhaust emission control device mounted in an exhaust system of an engine is equal to or higher than a predetermined temperature at a time of a request for stopping the engine, a hybrid vehicle including the engine and a motor continues fuel injection of the engine until satisfaction of a predetermined condition and stops fuel injection of the engine on satisfaction of the predetermined condition. When the temperature of the catalyst is lower than the predetermined temperature at the time of the request for stopping the engine, on the other hand, the hybrid vehicle immediately stops fuel injection of the engine.