Engine control method for heating of hybrid electric vehicle

An engine control method for heating of a hybrid electric vehicle, the method comprising:

• collecting information for air conditioning control from at least one sensor during operation of a heating, ventilation, and air conditioning (HVAC) device in the hybrid electric vehicle in which forced engine driving and pre-engine driving can be performed for heating;
• determining, by a controller, whether a condition that requires the pre-engine driving for heating engine coolant is satisfied based on the collected information;
• upon determining that the condition that requires the pre-engine driving is satisfied, determining, by the controller, whether a condition for allowing the pre-engine driving is satisfied based on engine efficiency and hybrid system efficiency information;
• and
• upon determining that the condition for allowing the pre-engine driving is satisfied, performing, by the controller, the pre-engine driving for driving an engine to manage engine coolant temperature,
• wherein the determining of whether the condition that requires the pre-engine driving is satisfied comprises:
• comparing discharge-port air temperature of the HVAC device obtained from the collected information with a predetermined pre-engine driving reference temperature;
• and
• determining that the pre-engine driving is required, when a difference between the discharge-port air temperature of the HVAC device and the predetermined pre-engine driving reference temperature reaches a predetermined temperature difference value,
• wherein the predetermined temperature difference value is a variation value determined based on an operation state of an air conditioning blower, an opening degree of a temperature door, and outdoor temperature detected by an outdoor temperature sensor.

An engine control method for heating of a hybrid electric vehicle, the method comprising:

• collecting information for air conditioning control from at least one sensor during operation of a heating, ventilation, and air conditioning (HVAC) device in the hybrid electric vehicle in which forced engine driving and pre-engine driving can be performed for heating;
• determining, by a controller, whether a condition that requires the pre-engine driving for heating engine coolant is satisfied based on the collected information;
• upon determining that the condition that requires the pre-engine driving is satisfied, determining, by the controller, whether a condition for allowing the pre-engine driving is satisfied based on engine efficiency and hybrid system efficiency information;
• upon determining that the condition for allowing the pre-engine driving is satisfied, performing, by the controller, the pre-engine driving for driving an engine to manage engine coolant temperature;
• and
• stopping the pre-engine driving when the coolant temperature or a discharge-port air temperature of the HVAC device obtained from the collected information during the pre-engine driving is elevated to a predetermined temperature variation value from a time point when the pre-engine driving is started;
• wherein the predetermined temperature variation value is determined based on an operation state of an air conditioning blower, an opening degree of a temperature door, and outdoor temperature detected by an outdoor temperature sensor.