(a) Field of the Invention
The present invention relates to a device and a method for learning an engine clutch contact point of a hybrid vehicle.
(b) Description of the Related Art
Recently, global environmental contamination has increasingly become a concern, and thus use of clean energy is becoming more important. Particularly, air pollution in major cities is becoming more severe, and exhaust gas of a vehicle is one of main causes of the air pollution. To solve the problem of exhaust gas and to reduce fuel consumption, an environmentally-friendly vehicle including a hybrid vehicle and an electric vehicle has been developed.
The hybrid vehicle has a power generation device formed with an engine and a motor, and is driven by appropriately using each of power developed by a combustion action of the engine and power generated by a rotation of a motor using electrical energy stored in a battery. In the hybrid vehicle, a transmission of a Transmission Mounted Electric Device (TMED) method that connects a driving motor and a transmission is generally applied. In the hybrid vehicle, to transfer power of the engine to a driving shaft, an engine clutch is mounted between the engine and the driving motor.
The hybrid vehicle provides an electric vehicle (EV) mode that in which the vehicle in run with a torque of a driving motor and a hybrid electric vehicle (HEV) mode in which the vehicle is run with the sum of an engine torque and a driving motor torque based on whether coupling of the engine clutch occurs. When the hybrid vehicle is converted from an EV mode to an HEV mode, after an engine speed and a motor speed are synchronized, in a power delivery process between the engine and the driving motor which are different power sources, by coupling the engine clutch thus preventing a torque from being changed, drivability can be secured.
Further, in the hybrid vehicle, a contact point learning of the engine clutch is important for stable power delivery. A dry engine clutch and a wet engine clutch are sensitive to temperature, so continuous learning may be needed. Particularly, with the dry engine clutch it is important to perform frequently learning, since the contact point of the dry engine clutch varies based on the temperature. Learning precision is increased when contact of the engine clutch or learning of the contact point is slowly performed, but learning of a contact point is stopped or cancelled based on a driving condition. When the contact or the contact of the engine clutch or the learning of the contact point is performed rapidly, learning cancelation may be decreased, but the learning precision may also be decreased.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.