In city driving, plug-in hybrid electric vehicles (PHEVs) generally offer better fuel efficiency than traditional hybrid electric vehicles (HEVs), primarily because of their ability to run on electric power alone for a significant portion of driving.
Key Differences Affecting Fuel Efficiency in City Driving
- Battery Size and Electric-Only Range:
HEVs have a small battery (around 1 kWh) that is charged through regenerative braking and the internal combustion engine, allowing short bursts of electric-only propulsion primarily at low speeds. PHEVs, on the other hand, have much larger batteries (10 to 20 times bigger), enabling fully electric driving for 20 to 50 miles per charge depending on the model. This ability means that in typical city driving—characterized by shorter trip distances and frequent stops and starts—PHEVs can operate a large percentage of the time solely on electric power if the battery is charged, drastically reducing gasoline consumption. - Regenerative Braking Utilization:
Both HEVs and PHEVs take advantage of regenerative braking to capture energy when slowing down, but the difference in battery size means PHEVs can store and reuse more energy before switching to gasoline, improving efficiency in stop-and-go traffic typical of city driving.
Real-World Fuel Efficiency Comparisons
- Studies and real-world data suggest PHEVs can be far more fuel efficient than HEVs in city environments when the PHEV is regularly charged and used for short trips within its electric-only range. For trips up to about 50 km, PHEVs show much higher fuel efficiency compared to HEVs.
- However, real-world efficiency depends heavily on charging habits. If the PHEV battery is not kept charged, it will operate mostly like a standard hybrid, narrowing the fuel economy advantages.
- Despite some discrepancy between claimed and actual fuel economy (PHEVs often show higher fuel use than advertised), PHEVs still typically use less fuel in city conditions compared to HEVs.
Summary
| Aspect | HEVs | PHEVs |
|---|---|---|
| Battery Size | Small (~1 kWh) | Large (10–20 times the size of HEV batteries) |
| Electric-Only Driving | Short bursts at low speeds | 20-50 miles per full charge |
| Fuel Efficiency in City | High due to regen and hybrid synergy | Higher if battery is charged; can drive mostly electric |
| Dependency on Charging | None (charges itself) | Must be plugged in to maximize efficiency |
In essence, for city driving where frequent charges are possible and trips are within electric range, PHEVs are more fuel efficient than HEVs due to their larger battery allowing extended electric-only operation. HEVs maintain consistently good fuel economy with no charging needed but cannot match the all-electric driving portion of PHEVs in urban stop-and-go conditions.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-fuel-efficiency-of-phevs-compare-to-hevs-in-city-driving/
