Hybrid Electric Vehicle (HEV)
HEV’s combine an electric motor and a gasoline engine to power the vehicle. The onboard battery and motor provide supplemental propulsion, mostly during heavy traffic and at low speed with frequent stop-and-start driving. The battery is charged from the engine and/or through regenerative braking. Depending on the configuration, some HEVs can be run on the electric power alone for very short distances.
How it works :
- There are three different ways to configure the motor and engine in a HEV: parallel, series, and series-parallel.
- A parallel HEV is the most common configuration, where the engine and motor are both mechanically coupled to the wheels and provide power simultaneously. In this case, both the engine and the battery are connected to an electric motor which is used to drive the wheels.
- A series-parallel HEV combines the two and gives the option of the electric motor driving the wheels alone for short distances. The electric only drive is usually only used at low speeds and startup.
Importance of HEVs:
- HEVs can achieve better fuel economy than traditional vehicles, especially for trips with high stop/start requirements
- HEVs produce lower emissions than traditional internal combustion engine (ICE) vehicles
- HEVs offer the flexibility of a traditional vehicle, with the added benefit of being able to use less fuel.
HEVs outlook:
- These vehicles were previously considered an interim solution for transitions to all electric vehicles, but have been outshone by plug-in hybrids as they can operate for longer periods of time at full electric.
Typical use case:
Light-duty vehicles.
Implications for operations:
- HEVS have extremely limited electric-only range if it is supported and a higher maintenance cost compared to BEVs