Hybrid Electric Vehicles (HEVs) were first popularized in the late 1990s. Primarily, through the introduction of hybrid car models such as the Toyota Prius. The Prius is considered to be the pioneer of hybrid cars. It single-handedly created the market for hybrid vehicles in the US. Now, HEVs are soaring in popularity due to rapid innovation in the automotive industry.
It’s not surprising why major automotive players like Toyota, BMW and Ford want to get ahead in the game. As climate change becomes more and more of a pressing issue. And people continue to realize how damaging gasoline car emissions are to the atmosphere. Electrification seems like a natural way forward in the automotive industry. Electric vehicles are undergoing incredible innovations that are constantly pushing the technical limits of earlier hybrids.
However, with so much buzz around electric cars and hybrids. It is hard to keep up with them and easy to get confused. The media uses ‘electric cars’ as an umbrella term with a very broad definition. It includes both full-electric cars like Battery Electric Vehicles (BEVs) and semi-electric cars like Hybrids.
There are many variations of ‘electric vehicles’ and they all employ different working technology. So, it is easy to confuse them all. Here, we aim to clear the air about some of the confusion around HEVs.
What Exactly Are Hybrid Electric Vehicles (HEVs)?
To start off, we need a clear picture of what HEVs really are. HEVs are a type of electric vehicle (EV). An EV refers to any vehicle that uses an electric power to carry out all or some of the key functions of the car. All full and semi-electric cars utilize an electric motor to carry out tasks in the car. This motor is driven by either a battery pack (collection of thousands of individual battery cells). Or a fuel cell (generates electricity through electrochemical reactions in the fuel cell).
Full electric cars like Battery Electric Vehicles (BEVs) and Fuel Cell Electric Vehicles (FCEVs) use only electric power to drive the vehicle. The electric current from either a battery pack (BEVs) or a fuel cell (FCEVs) are used to power an electric motor, which drives the car. So, they do not have internal combustion engines or any of its associated parts.
Hybrid Electric Vehicles (HEVs) are semi-electric vehicles that combine EV technology with regular gasoline powered cars. They use both electric power and gasoline to drive the vehicle. So, they use both an internal combustion engine and an electric motor. HEVs would also need both a fuel tank and a battery pack. HEV batteries cannot be charged using an external source. They are charged internally during regenerative braking (system to capture energy while braking).
Plug-In Hybrid Electric Vehicles (PHEVs) are also a variation of HEVs and are one of the most common and effective hybrid variants.
As hybrid vehicles partially rely on gasoline, they also produce emissions, but less than regular gasoline cars.
What’s the difference between HEVs and PHEVs?
As mentioned earlier, all EVs including all hybrids employ regenerative braking to recover some of the kinetic energy that would otherwise be lost as heat when a car brakes. The main difference between conventional hybrids and plug-in hybrids is that, the battery of a plug-in hybrid vehicle can be charged with an external source. In conventional hybrids, the batteries are only charged through regenerative braking. Hence, plug-in hybrids can rely more on electric power and travel a greater range using just electric power, compared to conventional hybrids.
In conventional hybrids, the electric motor is there to provide some support for the combustion engine, not to replace it. They will use electric power for small tasks instead of relying on it to drive the vehicle.
Since, plug-in hybrids can rely more on electric power, they produce less greenhouse gas emissions than conventional hybrids.
What are some examples of Hybrid Electric Vehicles (HEVs)
Some examples of conventional hybrid models include:
- 2005-2006 Chevrolet Silverado Hybrid
- Ford Fusion Hybrid
- Ford Escape Hybrid
- Toyota Prius
Plug-in Hybrid Vehicles are now more common. Some examples include:
- Hyundai Ioniq Hybrid- widely considered to be the top hybrid car of recent years
- Toyota Prius Plug-In Hybrid
- 2018 MINI Cooper SE Countryman
- 2018 KIA Niro
- 2007 Hyundai Sonata
- 2018 KIA Optima
- 2018 Honda Clarity
How do HEVs work?
In a nutshell, HEVs work by using both the internal combustion engine and the electric motor during the conditions where they work best. Usually, at low speeds, electric motors are quite effective and can produce high torque. Combustion engines can’t produce high torque at low speeds. Hence, the electric motor is used at these speeds. At higher speeds, the combustion engine is more effective, so it is used at higher speeds.
The switch between the motor and combustion engine is determined electronically, where the system decides which one gives the optimum performance at the current driving conditions.
What are the main components of an HEV/PHEV?
Electric Motor
This is the main motor used for propelling the vehicle and draws electric power from the battery pack. Some EVs use a motor-generator that act as both a motor to drive the vehicle and a generator to produce current from regenerative braking.
Battery Pack
A collection of individual battery cells that store electrical energy for use by the electric motor to drive the vehicle. Hybrids rely only partially on electric power, so the battery pack doesn’t have to be as big and powerful like in full electric vehicles.
The type of batteries used depends on the type and manufacturer of the car. Some manufacturers use Lithium-Ion but for hybrids, the most commonly used battery type is Nickel-Metal Hydride as it is more economical than Lithium-Ion.
Internal Combustion Engine
Fuel is injected either into combustion chamber or intake manifold. The fuel-air mixture is ignited with a spark plug to move the piston.
Gasoline Fuel Tanks
Stores gasoline onboard the vehicle.
Auxiliary Battery
Used in addition to the battery pack for small functions like starting the car and to power accessories.
DC/DC Converter
Steps down voltage of the power from the battery pack to the low voltage needed for the accessories to work.
Power Controller
This electronic system controls the amount of current that flows from the battery pack to the electric motor, thereby controlling its speed, torque and the speed of the car itself.
Transmission System
Delivers mechanical power from the engine using a system of gears to drive the wheels. This can be used with or instead of the electric motor to deliver power to the wheels.
Charging Port
For PHEVs, it allows the battery pack to be charged using an external power source.
Cooling Systems
Maintains an optimal vehicle temperature needed for the electric motor, power controller and engine to function smoothly.
Inverter/Onboard Charger
The current coming from the external power source during charging is in AC. The charger converts this AC current into DC current that is compatible with the battery pack to be stored.
What are the main advantages of a Hybrid Vehicle over regular cars?
There are a myriad of benefits of choosing a hybrid vehicle over a regular gasoline car.
Superior Fuel Economy
For regular petrol or diesel cars, the fuel economy simply means how much distance the car can travel in miles per gallon of fuel and is measured in miles per gallon (mpg). As electricity is not measured in gallons, the fuel economy for full-electric cars and hybrids are measured in equivalent miles per gallon (MPGe).
Here, consider the amount of electricity with the same energy as a gallon of fuel and how far the car can travel with this amount of electricity. Regular petrol and diesel cars, even some of the top ones have MPGs I the range 30-65. With hybrid vehicles, particularly plug-in hybrids, MPGs can reach up to 130 MPGe. The Toyota Prius Hybrid has a fuel economy of 133 MPGe (electric and gas combined) and a regular gas MPG of 54. Meanwhile the Honda Clarity has a rating of 110 MPGe (combined electric and gas) and a regular gas rating of 42 MPG.
Hybrids have better fuel economy because electric motors are more efficient than combustion engines, and they have energy saving mechanisms such as regenerative braking, which means less fuel is wasted as heat.
Better Range
As hybrids tend to have better fuel economy than regular gasoline cars, some of them can have really high ranges that are high enough to compete with top gasoline powered cars. Another important factor to look at for an HEV is the all-electric range. This is the maximum distance that can be travelled using electric power alone, without engaging the combustion engine. The higher the range, the longer you can go without charging and the less emissions you will release. Some top PHEVs with high all-electric ranges include:
- 25 miles – 2018 Toyota Prius Prime
- 29 miles – 2018 Hyundai Ioniq Plug-In
- 26 miles – 2018 Kia Niro Plug-In
- 47 miles – 2018 Honda Clarity
- 53 miles – 2018 Chevrolet Volt
Lower Emissions
Because hybrid vehicles tend to have better fuel economy, they tend to use less fuel to travel the same distance. Hence, they release lesser emissions. The higher their maximum all-electric range, the lower the emissions would be.
Lower Fuel Costs
Especially for Plug-In Hybrids where you can rely more on electric power and less on gasoline fuel, you can make significant fuel cost savings per year. This is because generally, the price of electricity is lower than that of gasoline. Gasoline prices are also more volatile. In a study, it was found that using an electric vehicle can cut your fuel costs by more than half per year . This in comparison to regular gasoline vehicles.
Less Maintenance and Repair
Hybrid Electric Vehicles have more electronic control to change key functions in the car such as its speed. A lot of mechanical parts, do this in in gasoline vehicles. As a lot of moving mechanical parts are a source of failure for vehicles, with hybrids you can save maintenance and repair work, and associated costs.
How do you charge a hybrid vehicles?
Charging is mainly for plug-in hybrid vehicles as you can’t charge a conventional hybrid vehicle. An external power source can charge plugin hybrids. You can use standard 120V outlets at home, but this will take a while to reach full charge. Usually, if you charge with this method at home, you will need to leave the car overnight to get full charge.
A faster way to charge is using an EVSE (Electric Vehicle Supply Equipment) that operates on a 220/240V circuit. The time it takes to charge can vary depending on the type of car and battery. Typically, an hour of charging on an EVSE will add 10-25 miles of range. So, it would take 2-3 hours to be fully charged. You can get your own EVSE or head to an EV charging station.
