Baba’s Explainer – Hybrid Electric Vehicles (HEV)

There are four types of electric vehicles available:

• Battery Electric Vehicle (BEV):Fully powered by electricity. These are more efficient compared to hybrid and plug-in hybrids.
• Hybrid Electric Vehicle:
  • Hybrid Electric Vehicle (HEV): The vehicle uses both the internal combustion (usually petrol) engine and the battery-powered motor powertrain. The petrol engine is used both to drive and charge when the battery is empty. These vehicles are not as efficient as fully electric or plug-in hybrid vehicles.
  • Plug-in Hybrid Electric Vehicle (PHEV): Uses both an internal combustion engine and a battery charged from an external socket (they have a plug). This means the vehicle’s battery can be charged with electricity rather than the engine. PHEVs are more efficient than HEVs but less efficient than BEVs.
• Fuel Cell Electric Vehicle (FCEV):Electric energy is produced from chemical energy. For example, a hydrogen FCEV.

• Hybrid electric vehicles are powered by an internal combustion engine and one or more electric motors, which uses energy stored in batteries.
• A hybrid electric vehicle cannot be plugged in to charge the battery. Instead, the battery is charged through regenerative braking and by the internal combustion engine. The extra power provided by the electric motor can potentially allow for a smaller engine.
• Key Components of a Hybrid Electric Car
  • Battery (auxiliary): In an electric drive vehicle, the low-voltage auxiliary battery provides electricity to start the car before the traction battery is engaged; it also powers vehicle accessories.
  • Traction battery pack: Stores electricity for use by the electric traction motor
  • Electric generator: Generates electricity from the rotating wheels while braking, transferring that energy back to the traction battery pack. Some vehicles use motor generators that perform both the drive and regeneration functions.
  • Electric traction motor: Using power from the traction battery pack, this motor drives the vehicle’s wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.
  • Fuel tank (gasoline): This tank stores gasoline on board the vehicle until it’s needed by the engine.
  • Internal combustion engine (spark-ignited): In this configuration, fuel is injected into either the intake manifold or the combustion chamber, where it is combined with air, and the air/fuel mixture is ignited by the spark from a spark plug.
  • Power electronics controller: This unit manages the flow of electrical energy delivered by the traction battery, controlling the speed of the electric traction motor and the torque it produces.
  • Thermal system (cooling): This system maintains a proper operating temperature range of the engine, electric motor, power electronics, and other components.
  • Transmission: The transmission transfers mechanical power from the engine and/or electric traction motor to drive the wheels.

HEV powertrains are designed to power cars in a series, parallel or series-parallel (power split) methods.

• A series HEV uses only the electric motor to drive the wheels, while the ICE powers the generator, which in turn recharges the battery.
• A parallel HEV, based on the driving condition, uses the best power source to power the vehicle. It will alternate between the electric motor and the ICE to keep the car moving.
• A series-parallel HEV offers a combination of both models and allows to split power, wherein power is routed from the ICE alone or from the battery to the electric motor to drive the vehicle.
• Moreover, in all three designs, the battery is charged through regenerative braking technology.

• Hybrid and electric vehicles apply battery technology, aerodynamics, and other engineering advancements to achieve efficiency in driving. One such feature employed by these energy-saving vehicles is regenerative braking.
• Regenerative braking captures energy that is otherwise lost during braking and then uses this power to help recharge the vehicle’s battery.
• Understanding how regenerative braking works first requires knowledge of how a conventional braking system operates. When you step on a vehicle’s brake pedal, the discs and the brake pads create friction as they meet. In turn, the friction creates kinetic energy that dissipates into the environment in the form of heat.
• Regenerative braking recovers some of the kinetic energy that would otherwise turn into heat and instead converts it into electricity.
• In this system, the motor drives the wheels during acceleration or cruising, but the wheels drive the motor while decelerating. This two-way energy flow allows the motor to act as a generator, resisting the rotation of the wheels and creating electricity to recharge the vehicle’s battery.
• There are two conditions when regeneration occurs:
  • When the driver applies the brake pedal
  • When the driver releases the accelerator pedal, and the vehicle is coasting
  • In both cases, the system creates electricity to recharge the battery
• The amount of electricity the system generates is proportional to the level of braking force. That means the stronger the braking force, the greater the electrical current. Ultimately, the amount of energy the system captures is dependent on the vehicle’s speed and the duration of brake application.
• The efficiency of HEVs and EVs will in large part be determined by their ability to recover as much energy as possible while braking, with a higher degree of energy recovery lowering fuel consumption.
• While regenerative braking systems are already available in most EVs, the technology is also used in electric railways. Rail transit can be described as frequent acceleration and braking of trains across many stations. This increases the potential for braking energy recovery using energy storage systems.

• Better braking efficiency in stop-and-go traffic which enhances fuel economy
• Also helps in reducing carbon emissions.
• RBS also helps in energy optimisation resulting in minimum energy wastage.

• The HEVs can be categorised into micro, mild and full hybrid vehicles, based on the degree of hybridisation.
• A full HEV will have a larger battery and a more powerful electric motor compared with a mild HEV. As a result, a full HEV can power the vehicle for longer distances using just electric mode.
• A mild HEV cannot drive using only the electric motor and uses the battery at traffic lights or in stop-and-go traffic to support the ICE.
• Micro hybrids do not offer electric torque assistance as they lack an electric motor, but they have an idle stop-start system and energy management functions.

The hybrid variants of the Maruti Suzuki’s Grand Vitara and the Toyota’s Urban Cruiser Hyryder can be classified as full and mild hybrids.

• Full HEVs offer better fuel economy compared with the other two types of HEVs but they also cost more than them.
• Plug-in hybrid electric vehicles (PHEVs) are just like full HEVs, but they can be charged using a wall outlet, as they have an onboard charger and a charging port. PHEVs generally use the electric motor until the battery is almost drained, and then automatically switch to the ICE.
  • PHEVs accounted for about 23% of 1.95 million global EV shipments in the first quarter of 2022

• Fuel efficiency: The design of hybrid vehicles for reduced engine size and car weight as compared to ICE vehicles, translates into increased mileage.
• More power: With the increase in total power and torque, HEVs can deliver instant torque and provide high torque even at low speeds.
• Minimum emissions: Better fuel efficiency means less carbon footprint of these vehicles, thus helping move towards the goals set out in Paris Climate Accord.
  • To ensure a positive growth rate towards achieving India’s Net Zero Emissions by 2070, a transportation revolution is required in India. The transition to electric mobility is a promising global strategy for decarbonising the transport sector.
• Disruption-free Technology Transition: HEV helps in creating a local EV parts manufacturing eco-system while simultaneously protecting the huge existing investments and jobs related to ICE parts manufacturing thus ensuring a faster and disruption-free technology transition.

• In a price-sensitive market like India, one of the major challenges for HEVs is the high vehicle cost.
• Battery, a vital component of an HEV, increases the cost of the vehicle, making it pricier than vehicles powered only by an ICE. The RBS also adds to the higher cost of an HEV.

• India is among a handful of countries that support the global EV30@30 campaign, which aims for at least 30% new vehicle sales to be electric by 2030.
• The remodeled Faster Adoption and Manufacturing of Electric Vehicles (FAME II) scheme.
  • The FAME India Scheme is aimed at incentivising all vehicle segments i.e. 2 Wheeler, 3 Wheeler Auto, Passenger 4 Wheeler Vehicle, Light Commercial Vehicles and Buses. The scheme covers Hybrid & Electric technologies like Mild Hybrid, Strong Hybrid, Plug in Hybrid & Battery Electric Vehicles.
• Production-Linked Incentive (PLI) scheme for Advanced Chemistry Cell (ACC) for the supplier side
  • It aims to give companies incentives on incremental sales from products manufactured in domestic units.
• Government has also launched PLI scheme for Auto and Automotive Components for manufacturers of electric vehicles.

The automotive industry is transitioning, with an increasing focus on hybrid and battery electric vehicles (BEVs or EVs). Meanwhile, the rise in fossil fuel prices, increase in the adoption of clean mobility solutions, and stringent government norms for emission control drive the growth of the global EV market.