Types of Hybrid Vehicles

Hybrid vehicles have surged in popularity since their introduction to the mainstream market with the 2000 Toyota Prius, more than doubling in sales between 2016 and 2021. The term hybrid is a loose one though, as it refers to any electrically assisted internal-combustion vehicle.

Manufacturers have tried various approaches to hybrid systems, and not all are created equal. In this article, we’ll cover the most common types of hybrid vehicles as well as the pros and cons of each. 

Mild Hybrids

As the name implies, mild hybrids don’t rely too much on their electrical motors but rather use them to provide the engine with a slight boost during acceleration. Mild hybrids don’t have enough power to drive the vehicle on electric motors alone, but the extra kick they add reduces the amount of engine power it takes to get up to speed which increases efficiency.

Mild hybrids don’t need to be plugged in like some other hybrids, as they instead use a combination of power produced by the engine and regenerative braking.

Regenerative braking is a pretty ingenious way of powering the hybrid system, as it’s able to capture energy from braking and convert it to electricity. Otherwise, this energy would simply be lost as thermal and kinetic energy during braking, so regenerative braking makes what was unusable energy into usable energy. If you’re a Formula 1 fan, this is the same principle as the Kinetic Energy Recovery System (KERS) that modern F1 cars use to power their hybrid assists.

In practice, this allows the energy produced by braking for a stoplight to be recycled, helping the vehicle accelerate while delaying the use of the combustion engine. 

Full Hybrids

Full hybrids operate similarly to their mild counterparts, however, motors of a full hybrid can sustain driving on electric power alone. This full-electric mode is often used during slow city driving, giving these hybrids some of the best city fuel economy on the market. A good majority of the hybrids you see on the road are likely full hybrid systems.

Like mild hybrids, these systems use engine-generated power and regenerative braking rather than requiring plug-in charging. 

Most full hybrid systems fall into one of three categories: parallel, series, or series-parallel.

Parallel Hybrid

In a parallel hybrid, both the engine and electric motors can operate simultaneously or independently. This essentially gives the hybrid system three modes: full-electric, full-gasoline, or a mix of both. 

At lower speeds, the electric motors carry most of the workload since this is where electric motors can best make use of their instant torque and regenerative braking. Once the vehicle has reached a sufficient speed, the engine will kick in and take over the brunt of the work. From this point, the vehicle’s computers will select the optimal combination of engine and electric power for efficiency.

Some parallel hybrids make use of a single electric motor that sits between the engine and transmission, while others use a pair of two motors that act similarly to a continuously variable transmission. 

Series Hybrid

Series hybrid systems are the original, as Ferdinand Porsche equipped his Lohner-Porsche Mixte with one back in 1899. While hybrids never caught on the way Porsche expected during the 20th century, the design of the series hybrid system would live on to be resurrected in modern hybrids over a century later. 

The series hybrid concept is a stark departure from parallel hybrids, as the gasoline engine is never used to drive the wheels but is instead exclusively used as a generator for the electric motors. The motors drive the vehicle for the entirety of its trip, while the engine kicks in occasionally to provide the motors with power. 

Since the vehicle is always electrically driven, series hybrid vehicles provide a seamless driving experience as the gasoline engine never needs to engage with the drivetrain itself. However, this is also one of its largest downsides, as the extra step of converting the engine’s mechanical energy to electricity reduces efficiency. 

Series-Parallel Hybrid

Somewhere in between the series and parallel system is a combination of both, which is aptly known as a series-parallel hybrid (engineers aren’t exactly known for their creative names). There’s no strict definition of what these systems look like, besides including the ability to operate both as a parallel and series system. The lines may be blurred, but most new non-plug-in hybrids include some ability to incorporate the benefits of both parallel and series hybrids and subsequently fall into this category. 

Each manufacturer of a series-parallel hybrid goes about managing the hybrid system differently, making use of their computers and software to select the optimal mode and power-split for that situation. 

When you think of hybrids, the Toyota Prius likely comes to mind. Toyota has been pushing hybrid technology since the late 90s and is renowned for its series-parallel hybrid system used in Prius models and other Toyota hybrids since 2001. 

Black Toyota Prius driving

Plug-In Hybrids

The hybrid systems we’ve discussed above all generate their power through the means of the engine and regenerative braking. While this is great for hybrids that typically only use their electrical motors for assistance, driving on electric power alone for longer periods requires a large deal of electricity and by extension a larger battery. Plug-in hybrids still use internal measures to generate power, but these can only produce so much electricity, needing external charging for sufficient battery life. 

Plug-in hybrid charging port

This is the benefit of plug-in hybrids, while not generating all of their power, can drive solely on their electric motors for much longer. It’s this major difference that makes plug-in hybrids and good middle-ground choices between a traditional hybrid and a full-electric vehicle. 

Hybrid Services in Austin, Texas

If you’re looking for the premier hybrid vehicle service and repair in Austin, trust the experienced technicians at Edgestone Automotive! Our team has the training and equipment needed to properly service any make or model of hybrid. Give us a call or schedule online today to speak with our friendly and knowledgeable service advisors about the next step for your vehicle!