A hybrid car is a car that uses both an internal combustion engine and an electric motor for power, and only gasoline as fuel. (There are diesel hybrids, but these are mainly used in locomotives and other large vehicles.) Hybrids have a small high-voltage battery to power the electric motor, but it is not plugged in. How does a hybrid car work?
Without an external power source, braking generates power for the motor, a process called regenerative braking (or regen for short). F1 fans may have heard of a kinetic energy recovery system (KERS). Regenerative systems do not replace traditional braking, but they do act as an important alternative.
The electrical energy collected in this process is stored in the battery and can be quickly reused the next time you accelerate. When you pull away from the traffic light, the stored energy gets the car moving again, possibly delaying the restart of the petrol engine until you reach 40 mph. When you come to a stop again, the cycle repeats.
This means that a hybrid’s fuel consumption in town is much lower than that of a non-hybrid car, not to mention on the highway.
How does regenerative braking work?
Regeneration is a natural consequence of electric motor operation. When you power an electric motor, it makes the car move (or helps it move). When the car is moving, that same motor becomes a generator, reversing the flow of electrons and using that motion to send electricity back to the battery. For this reason, hybrid electric motors are sometimes called motor-generators.
Importantly, this process slows the car down, so regeneration is triggered when braking or going downhill, and is controlled by a computer.
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How small is a hybrid’s battery?
- Typically it is no more than 1 kWh, which is only 1 to 2 percent of the size of a full electric vehicle’s battery.
- One-pedal driving, the process in which regeneration begins when you lift the accelerator pedal, occurs primarily in fully electric vehicles rather than hybrids because electric vehicles have larger-capacity electrical systems and much larger batteries.
How small is a hybrid’s battery?
Typically it is no more than 1 kilowatt-hour (kWh), which is only 1 to 2 per cent of the size of a full electric vehicle’s battery. Still, hybrid regeneration is strong enough for most everyday braking. A computer constantly monitors how hard you press the brake pedal, and activates the traditional brakes – the brake pads and rotors – during harder braking or in emergencies.
This regenerative approach maximizes the collection of electricity for propulsion and significantly reduces fuel consumption. While regeneration is a fundamental element common to all hybrids, there are differences in how the gasoline engine is used.
Parallel Hybrid
This is the most common type, as it is set up to use either the gasoline engine or the electric motor to power the car. Both can also be on at the same time. The electric motor is recommended for use at low speeds, as its high initial torque and efficiency allow it to make the most of limited battery energy.
After a delayed restart, the gasoline engine fires up and eventually takes over as the speed increases, settling into a steady speed where the engine is in its optimum range.
Some designs use a single motor sandwiched between the internal combustion engine and a conventional transmission, while others use an arrangement of two electric motors that work together to act as a continuously variable transmission for the internal combustion engine.
Series Hybrid
This type is less common but is becoming increasingly popular. These vehicles also have a main drive motor that uses regenerated battery energy to power the vehicle at low speeds and recovers energy under braking. As speed increases and energy becomes low, the engine starts to power a second generator, which converts gasoline energy into electricity to power the battery.
This means that the wheels are driven electrically at any speed, and power delivery is always smooth and seamless. The downside is that the extra step of converting gasoline to electricity reduces efficiency, but new approaches have made this less of a concern. Honda is the latest pioneer of this type, with it featured in the latest versions of the Civic, CR-V and Accord Hybrid.
Blurred Boundaries
Like anything else, hybrid systems don’t strictly adhere to such definitions. Toyota’s Hybrid Synergy Drive is primarily a parallel system, but the dual-motor design also allows for short periods of continuous power production when the engine’s most efficient operating speed produces more power than the driver needs.
Similarly, Honda’s latest primary series hybrid system can engage the engine under certain conditions to drive the wheels directly if the computer determines that it would be more efficient. Both exceptions are appropriate, as they show that engineers are looking for the most efficient solution, not the most explainable one.
Advantages of Hybrids
- The main advantage of a hybrid is that it can capture and reuse braking energy that would otherwise be lost in the form of heat and wear on the brakes.
- The cars that most people are interested in utilize this recovered energy to save fuel, reducing fuel consumption by using an electric motor to delay the start of the gasoline engine.
- Sporty hybrids, however, use the gained energy to improve overall performance and speed.
- Fuel-efficient hybrids are an excellent choice for anyone looking to save money or reduce their carbon footprint.
- After all, low fuel consumption and low CO2 emissions are two sides of the same coin.
- If you live in an apartment or have only one car, an electric car may not be practical.
- A hybrid, on the other hand, is a purely gasoline-powered vehicle that’s not tied down by strings or special fuel requirements.
- In more practical terms, hybrids’ emphasis on regenerative braking means that brake pads and rotors last much longer than in regular cars.
- Plus, because this is done by an electric motor, there’s no separate starter.
- Also, a hybrid’s small battery takes up less space and there is no need for expensive battery chemistry.
Other Hybrid Types
- Mild hybrids (also called belt starter alternators or BAS hybrids) have a modest 48-volt battery that can’t produce much driving force. But such systems charge through regeneration and combine the starter and generator into one unit to seamlessly start the engine “in gear,” so to speak, making start-stop systems work more smoothly.
- Fuel cell hybrids are serial hybrids with an electric motor, regenerative braking, and a small high-voltage battery, but no gasoline engine. Instead, they have fuel cells, devices that convert hydrogen gas into electricity, with water as the only by-product. So fuel cell hybrids run on electricity all the time and are as quiet as electric cars.
- The company’s hydrogen tanks can be filled up in five minutes, just like a regular car, but there are very few refuelling stations available, mostly in California’s major metropolitan areas.
- A plug-in hybrid is a regular hybrid with a significantly larger battery, designed to run 20-50 miles (32-80 kilometres) at full speed on electricity alone. All the issues with charging an electric car’s battery come into play here, but they are less severe because a plug-in hybrid’s battery is only about a quarter the size of an electric car’s.
- This makes it easy to plug in at home, and those who do end up owning a part-time off-leash electric car.
- An electric car for the weekday commute, but with full gasoline for long-distance trips. And it’s still efficient when running on gasoline, so it retains the benefits of a regular hybrid.
Disadvantages include higher initial cost due to the larger battery, a larger battery is likely to take up more cargo space, and a potentially smaller gas tank.
What is a self-charging hybrid car?
A self-charging hybrid car is any hybrid model that can self-charge using energy from its internal combustion engine and brake regeneration without needing to be plugged into a charger at start-up. If you want to reduce your fuel costs and emissions but don’t want to install an electric vehicle charging station, a self-charging hybrid car may be the right choice.
Plug-in hybrid cars can also self-charge, but they work best when they can be plugged into a power outlet to charge.
What is the difference between a hybrid car and an electric car?
The main difference between hybrid and electric cars is that fully electric models do not have an internal combustion engine, while hybrid models have an internal combustion engine, a battery, and an electric motor.
Electric cars also need to be plugged into a power outlet to charge, but some hybrid cars charge automatically and do not need to be plugged into a power source at all.
This means that you can drive a hybrid car even if its battery is empty, as long as there is fuel to run the internal combustion engine.
Keep in mind that having an empty battery is not a good thing, so try to load them up if possible. Another difference between the two vehicles is that electric cars do not emit exhaust fumes.
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