Engine start control apparatus for hybrid vehicle

摘要

In a hybrid vehicle, when using an ignition start to start a direct injection engine while any one of the cylinders has stopped near top dead center, engine revolutions are raised by producing a first explosion in a first cylinder, which is situated before a second cylinder in an ignition sequence and is in an expansion stroke and in which an exhaust value is not open, by directly injecting fuel into the first cylinder and igniting the fuel. Furthermore, assistance in increasing the engine revolutions is started by transmitting assist torque output from a motor-generator to the direct injection engine via a clutch, in a peak section immediately after the start of increase in the engine revolutions. The stopped direct injection engine can be started using a sufficient required assist torque, namely, electrical energy, whereby the electrical energy for engine starting that is always reserved in a battery (accumulator apparatus) is reduced and therefore a travel range is increased and vehicle fuel consumption is improved appropriately.

主权项

1. An engine start control apparatus for a hybrid vehicle including a direct injection engine directly injecting fuel into cylinders, a clutch connecting and disconnecting the direct injection engine with respect to a power transmission path, and a rotary machine functioning at least as an electric motor, the direct injection engine and the rotary machine being able to be used as drive power sources for travel, comprising:
a controller which is configured to, when starting up the direct injection engine in a state where a second cylinder of a plurality of cylinders is positioned at top dead center, raise engine revolutions by producing a first explosion in a first cylinder situated before the second cylinder in an ignition sequence, the first cylinder being in an expansion stroke and an exhaust valve thereof not being open, by directly injecting fuel into the first cylinder and igniting the fuel, and start assistance in increasing the engine revolutions by transmitting assist torque output from the rotary machine to the direct injection engine via the clutch, in a peak section after the engine revolutions start to increase, the peak section being a section indicating engine revolutions of no less than a value having a prescribed ratio with respect to a maximum value between an increase section of the engine revolutions and a decrease section following increase section of the engine revolutions.