What are the different types of hybrid drive systems?

February 19th, 2019 by

Mitsubishi Outlander PHEV

Hybrid cars carry some of the most cutting-edge technology on the automotive market today. There’s a good reason hybrid powertrains made their ways into this decade’s hypercars, like the Ferrari LaFerrari, McLaren P1, Porsche 918 Spyder, and the upcoming Ferarri SF90 Stradale.

While those dream cars may be unreachable for nearly everybody, similar hybrid tech is humbly put to work in all sorts of daily drivers like the Honda Insight, Mitsubishi Outlander Plug-in Hybrid, and the Toyota Prius Prime – offering efficiency and comfort benefits over cars solely powered by internal combustion engines.

Cutting-edge tech comes with cutting-edge complications though, and we often get questions about how the different driving modes available in today’s hybrid cars: What do they mean? And how do they work?

We’re here to explain that now. Let’s break it down into the three main types:

EV Mode

And this is the simplest of them all. The battery and electric motor do all the work, from getting the car started to keeping it at cruising speed.

Of course, this is the most efficient way to go since no gas is being used. But for plug-in hybrid vehicles, battery size limitations mean the available electric-only range is relatively short. Once that’s used up, it transitions into the other modes.

EV Mode

                                      EV Mode – Black icons and blue arrows indicate flow of power. 

Series Hybrid Mode

In this mode, the internal combustion engine is only used to charge the battery, while the electric motor still does all the driving. The engine will usually run at one predetermined RPM, whatever is most efficient.

Manufacturers have different approaches as to when the engine will engage. In the BMW i3 REx, it only turns on when the battery is entirely out of charge. Meanwhile, the Chevy Volt doesn’t want the battery to empty completely, so the engine will turn on and off to keep the car juiced up.

Series Hybrid Mode

                                                                 Series Hybrid Mode

Parallel Hybrid Mode

Here the engine is used with (in parallel) the electric motor to drive the wheels. Under normal driving the electric motor is used to start the car, where its most efficient, while the internal combustion engine engages at higher speeds where it is most efficient and the electric motor’s torque diminishes. Any extra power generated by the engine is used to charge the battery.

If launching the car hard from a stop, both the electric motor and the internal combustion engine will work together to propel the car. They provide more power, and therefore speed, together than on their own!

An example of a solely parallel hybrid car is the classic Toyota Prius (not the new plug-in Prius Prime).

Parallel Hybrid Mode

                                                               Parallel Hybrid Mode

So what do most cars use today?

Most modern hybrids can actually use all three different modes, as each has distinct advantages for different points of driving.

Some cars, like the Honda Insight, will choose the driving mode on their own based on how you’re driving and how charged the battery is. Others like the Mitsubishi Outlander Plug-in Hybrid and Toyota Prius Prime will normally run automatically while buttons are available for you to override the car into running into electric-only mode, or charge-the-battery series hybrid mode.

The clever use of these modes ensures that hybrid powertrains maximize their potential for power, efficiency, and comfort over cars driven by conventional engines.