Scientific paper ID 2234 : 2022/3

Hybrid electric vehicles are environmentally friendly and economical vehicles with high efficiency in urban traffic conditions. Intensive traffic in large urban agglomerations is characterized by frequent starts and stops of vehicles, waiting for delays in front of traffic lights, frequent changes in speed associated with acceleration, deceleration, stopping, subsequent departure and acceleration, etc. This mode of driving with frequent starts increases the fuel consumption of the classic vehicle due to the operation of the internal combustion engine in partial modes with high specific fuel consumption, which in turn increases harmful emissions. The hybrid electric vehicle uses two energy sources, one of which is an internal combustion engine and the other an electric motor powered by a rechargeable battery. The combination of two energy sources gives certain advantages of the hybrid electric vehicle over the classic one, which are expressed in the possibility to reduce fuel consumption during frequent starts of the vehicle. Starting can be done with an electric motor and stopping can be used for recuperative charging of the battery. The study of this driving mode is essential to assess the effectiveness of hybrid electric vehicles.

The article considers the influence of the start driving mode on the fuel consumption of a parallel hybrid electric vehicle in the traffic conditions of the city of Sofia.