Systems and methods for operating a driveline of a hybrid vehicle are disclosed. In one example, an engine may enter or stay in one of two cylinder modes in response to a request to a negative torque capacity of an electric machine being insufficient to provide a desired driveline braking torque. One cylinder mode operates cylinders with cylinder valves held closed and without fuel being injected to the cylinders while the other cylinder mode operates cylinders with valves that open and close without fuel being injected to the cylinders.

A corner determinator detects a corner appearing in a traveling direction of a vehicle and determines whether a detected corner is a blind corner based upon a current position of the vehicle and road data. A blind distance calculator calculates a distance from the determined blind corner to the vehicle based upon the current position of the vehicle and the road data. A necessary engine braking amount calculator calculates, on the basis of a calculated distance, a necessary engine braking amount necessary for decelerating a current vehicle speed to a vehicle speed at which it is possible to stop around the blind corner when a braking operation is performed with a full braking amount. A required speed change stage determinator calculates a required speed change stage based upon the determined necessary engine braking amount. A transmission controller performs a downshift to a determined required speed change stage.

A transmission controller includes: a corner detector that detects a corner; a predictor to predict a rolling amount based upon road data when the corner is detected and an accelerator opening degree is fully closed; a device to determine a first necessary engine braking amount in accordance with the rolling amount; a device to determine a first required speed change stage corresponding to the first necessary engine braking amount; a calculator to calculate a second necessary engine braking amount when the corner is detected and the accelerator opening degree is fully closed based upon a minimum required inter-vehicle distance with the vehicle ahead; a device to determine a second required speed change stage corresponding to the second engine braking amount; and a transmission controller to select, as a target speed change stage, either smaller one of the first or second required speed change stage, and then perform downshift control.

A control device, system and method that distribute a braking request to at least one of a powertrain and a brake based on a braking request by driver operation and a braking force that is generable by the power train. When the braking request is larger than the braking force that is generable by the powertrain, the device, system and method instruct a controller of the powertrain to generate the braking force that is generable by the powertrain, and to instruct a controller of the brake to generate a braking force corresponding to a difference between the braking request and the braking force that is generable by the powertrain.

In a hybrid vehicle configured such that a sun gear, a carrier and a ring gear of a planetary gear are respectively connected with a rotating shaft of a motor MG1, a crankshaft of an engine and a driveshaft and that a motor MG2 is connected with the driveshaft, when a required braking force that is to be output to the driveshaft is equal to or less than a reference value Tref in an accelerator-off state, the braking force by engine braking is output to the driveshaft by motoring of the engine by the motor MG1. When the required braking force becomes greater than the reference value Tref, on the other hand, the power output from the engine by load operation of the engine in a reverse rotating direction is output as the braking force to the driveshaft.