Hybrid Electric Vehicles (HEV): Definition, benefits, types

Team AckodriveJun 6, 2022

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Electric vehicles (EVs) are the talk of the town as they are touted to be the future of mobility. EVs have revolutionised the automotive industry with advanced and innovative technology. However, they are still expensive and charging infrastructure remains to be a big question. Bridging the gap between conventional and electric cars are the Hybrid Electric Vehicles (HEVs). Read on as we discuss all the details related to HEVs.

hybrid electric vehicles

What is a Hybrid Electric Vehicle (HEV)?

A Hybrid Electric Vehicle is a type of vehicle that uses a combination of an Internal Combustion (IC) engine and an electric propulsion system. The electric powertrain may enhance fuel efficiency, increase performance, or independently propel the vehicle on pure electric power, depending on the type of hybrid system.

In simple words, an HEV is a vehicle that comprises a conventional fuel engine and an electric powertrain, wherein the electric motor assists the engine to extract more performance, and better fuel economy, depending on the type of the system. We will elaborate on the kinds of HEVs in the following sections of this article.

How does an HEV work?

Unlike an electric vehicle, the working mechanism of an HEV is relatively simple to understand. The below points explain how an HEV works.

  • Powering a hybrid electric vehicle is an IC engine and an electric motor.

  • The electric motor utilises the electrical energy stored in the battery pack.

  • The battery pack gets charged via regenerative braking or through a generator that is run by the internal combustion engine.

  • An HEV does not need to be plugged into a power source to charge the battery.

  • The electric motor and IC engine work in conjunction to propel the vehicle.

  • The additional power from the electric motor assists the engine, and it enhances the performance and improves the fuel economy.

  • The battery pack can also power other electrical components such as lights.

  • The electric powertrain also saves fuel via the engine start/stop technology, wherein the engine automatically shuts off when idle and starts automatically when the driver presses the throttle pedal.

Also, read: How do electric cars work?

Key components of a Hybrid Electric Vehicle

As mentioned before, an HEV combines a conventional engine and electric powertrain. Hence, you can find engine-related and electric powertrain components in an HEV. Below are the key components of a Hybrid Electric Vehicle.

  • Internal combustion engine: The primary power source of an HEV is a conventional engine. Hence, it is the main component responsible for propelling the vehicle. An HEV cannot run alone on an electric powertrain without an engine.

  • Electric motor: The secondary power source of an HEV is the electric motor. It assists the engine during initial acceleration to improve performance and fuel economy. It runs on electrical energy stored in the battery pack. It can also charge the battery when the vehicle is braking or coasting via the regenerative braking system.

  • Battery pack: A battery pack powers the electric motor. Basically, it acts as a fuel tank for the battery, wherein it stores the electrical energy via regenerative braking and the generator driven by the IC engine. The battery pack can also power auxiliary electrical components such as lights.

  • Generator: It is an essential component found in the series hybrid vehicle. We will touch upon what series hybrid is in the upcoming sections. A generator draws power from the IC engine to power the electric motor and charge the battery pack. In simple words, a generator converts mechanical energy into electrical energy.

  • Transmission: Typically, hybrid vehicles use conventional transmissions similar to petrol or diesel cars. It transmits the power produced by the IC engine to the drive shaft. The basic working principle of transmission remains the same, even in an HEV. It is one of the crucial components required to propel the vehicle.

  • Fuel tank: Similar to a conventional car, hybrid electric vehicles also have a fuel tank to store the conventional fuel. With the electric powertrain involved in a hybrid car, the fuel consumption will be comparatively less than a vehicle purely relying on an IC engine.

Types of Hybrid Electric Vehicles

There are three types of HEVs based on power delivery and distribution. Below are more details on the same.

1. Series hybrid

In a series hybrid system, the IC engine powers the electric generator, which drives the electric motor and charges the battery. In this setup, the engine does not directly power the wheels. Series hybrid is also called a range extender since the engine powers the electric motor and the battery pack.

2. Parallel hybrid

In this system, both the engine and electric motor work parallel to propel the vehicle. The engine and the electric motor deliver optimum power for the efficient functioning of the car. The battery pack gets charged via regenerative braking. If you wonder what regenerative braking is, here’s a brief explanation. Regenerative braking is a process of utilising the kinetic energy produced while slowing the vehicle down to charge the battery pack.

3. Series-parallel hybrid

A series-parallel is a flexible system wherein the IC engine, and electric motor can work in conjunction or independently. The power delivery or the power distribution helps the vehicle achieve maximum efficiency in terms of power output or fuel-efficiency.

Top 5 Hybrid Electric Vehicles in India in 2022

One of the significant highlights of Hybrid Electric cars is their fuel efficiency. With the help of the electric powertrain, they function more efficiently than their conventional counterparts. Below is the list of the top 5 HEV cars in India based on price, performance and fuel efficiency as of April 2022.

Model Fuel type Price (Ex-showroom Delhi) Fuel efficiency*
Toyota Camry Petrol Rs, 43.45 lakhs 19.16 kmpl
Lexus ES 300h Exquisite Petrol Rs. 56.65 lakhs 22.37 kmpl
Volvo XC60 Petrol Rs, 65.90 lakhs 11.2 kmpl
Volvo XC90 Petrol Rs. 93.90 lakhs to Rs. 1,31 crores 17.2 kmpl to 36 kmpl
MG Hector Petrol Rs. 17.15 lakhs to Rs. 18.50 lakhs 15.81 kmpl

*As per ARAI (Automotive Research Association of India) rating.

Also, read: Best electric cars in India

Advantages of HEVs

Below are some of the advantages of Hybrid Electric Vehicles.

  • They produce lower carbon emissions. Hence, HEVs are eco-friendly.

  • With the electric motor assisting the IC engine, the fuel consumption reduces. Hence, HEVs deliver an improved fuel efficiency.

  • HEVs consume less oil compared to their conventional counterparts.

  • They require lower maintenance than conventional cars. Hence, the maintenance cost is less.

Disadvantages of HEVs

Here are some of the disadvantages of Hybrid Electric Vehicles.

  • An HEV costs more than a conventional car. Hence, the upfront costs could be a problem if you are on a tight budget.

  • The repair costs of the electric powertrain may run high as it is a very complex system.

  • HEVs may produce less power than regular petrol or diesel cars. So, if you are a driving enthusiast, it may not suit your driving style.

Common misconceptions about Hybrid Electric Vehicles

We have compiled a few common misconceptions about HEVs to clear your doubts regarding hybrid vehicles.

  • HEVs are complicated to drive: It is one of the common myths about Hybrid Electric Vehicles. HEVs are easy to drive, and you drive them the same way as you drive any petrol or diesel. You need not learn any new technique to drive an HEV.

  • HEVs need to be charged: No, you need not plug in an HEV to charge the battery. The battery charges via regenerative braking or a dedicated generator onboard. So, you need not worry about charging an HEV.

  • HEVs are not eco-friendly: It’s a myth that Hybrid Electric Vehicles are not environment-friendly. HEVs consume less fuel and produce fewer carbon emissions compared to normal vehicles. Hence, they contribute to reducing vehicular pollution.

  • HEVs require special maintenance: No, Hybrid Electric Vehicles do not require special maintenance. In fact, they need less maintenance compared to conventional vehicles. Since the engine runs efficiently, it needs less maintenance and service intervals are also well spread out.

  • HEVs are not powerful: No, it’s not the case with modern Hybrid Electric Vehicles. They produce ample power to keep you engaged behind the wheel. With newer technology, the cars produce more power despite the smaller engine capacity.

Difference between Electric Vehicles and Hybrid Electric Vehicles

Below are the key differences between electric vehicles and HEVs.

Parameters Electric Vehicles Hybrid Electric Vehicles
Primary power source Electricity Gasoline fuel
Working mechanism Electric motor powers the wheels. The IC engine and electric motor work in tandem to propel the vehicle.
Battery charging You need to plug into a power source to charge the battery pack. You don't need to plug into an external power source as the battery gets charged via generator/regenerative braking.
Emission levels EVs produce zero emission. HEVs are Low Emission Vehicles (LEVs) since they produce fewer emissions than conventional vehicles.
Running cost Low High
Upfront cost (Price) High Lower than electric vehicles.
Driving range Low High
Vehicle life You can use an EV until the battery pack lasts. You can drive an HEV for a longer period since an IC engine lasts longer than a battery pack.

Future scope of HEVs

HEVs may not be a viable option for everyone as they cost more than conventional petrol/diesel cars. However, the new technology may make them affordable in the future. Hybrid Electric Vehicles play a vital role in bridging the gap between EVs and conventional vehicles. With better battery technology, they could be more efficient and provide an engaging driving experience. Also, expect HEVs to be more environmentally-friendly with advanced electric powertrains and efficient IC engines.

Frequently Asked Questions (FAQs)

Below are some commonly asked questions and their answers regarding Hybrid Electric Vehicles.

Which is a better option, a hybrid car or an electric car?

A hybrid car is a more practical option given the current scenario where the charging infrastructure is still in its infancy. Charging an EV could be a challenge; hence, an HEV makes more sense if you buy a car now.

Which are the high voltage components of a Hybrid Electric Vehicle?

Electric motor, battery pack, onboard charger, and compressor are some of the high voltage components of an HEV.

What are the benefits of a mild Hybrid Electric Vehicle?

Below are some of the benefits of mild HEVs.

  • They are less expensive than full hybrid vehicles.

  • They have less complex components. Hence, cheaper to repair.

  • Mild HEVs enhance fuel efficiency.

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