The Kia Hybrid Electric Vehicle (HEV) uses both the gasoline engine and the electric motor for power. The electric motor is run by a 240V high-voltage HEV battery.
Depending on the driving conditions, the HEV computer selectively operates between the engine and the electric motor or even both at the same time.
Fuel efficiency increases when the engine is at idle, or when the vehicle is driven by the electric motor with the HEV battery.
The HEV battery charge must be maintained for the times when the engine acts as a generator, such as when stopped at idle. Charging also occurs when decelerating or by regenerative braking.

Niro hybrid energy flowKia Niro 2017 (DE HEV) Service Manual: Fuel Filter Repair procedures
Removal
1.
Remove the fuel pump.
(Refer to Fuel Delivery System - "Fuel Pump")
2.
Disconnect the fuel pump motor connector (A) and fuel sender connector
(B).
3.
Lift the fixing hook (A) by using ...
Kia Niro 2017 (DE HEV) Service Manual: Description and operation
Operation
1. Cooling Fan
2. cooling duct (inlet)
3. outlet cooling duct (outlet)
...