Hybrid Electric Vehicle


    In News

    • In recent months, various automakers have launched hybrid electric vehicles in India.

    Hybrid Electric Vehicle (HEV)

    • About:
      • A HEV uses an internal combustion engine (ICE) (a petrol/diesel engine) and one or more electric motors to run.
      • It is powered by the electric motor alone, which uses energy stored in batteries, by the ICE, or both. 
    • Components:
      • a low-voltage auxiliary battery, 
      • a traction battery pack to store electricity for the electric motor, 
      • an electric generator, 
      • an AC/DC converter, 
      • a power electronics controller, 
      • a thermal system to maintain working temperature, 
      • a conventional ICE, 
      • a fuel tank, a fuel filler, 
      • a transmission and an exhaust system.
    • Working:
      • 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 split power, wherein power is routed from the ICE alone or from the battery to the electric motor to drive the vehicle. 
      • In all three designs, the battery is charged through regenerative braking technology.

    Different Types of HEVs

    • Micro HEV:
      • These do not offer electric torque assistance as they lack an electric motor, but they have an idle stop-start system and energy management functions. 
    • Mild HEV:
      • A mild HEV cannot drive using only the electric motor 
      • Uses the battery at traffic lights or in stop-and-go traffic to support the ICE
      • Employ regenerative braking and some level of power assist to the ICE
    • Full HEV: 
      • 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.
      • 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) 
      • These 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.
    • Strong-hybrid electric vehicles (SHEVs):
      •  SHEVs use RBS for self-charging the HEVs. 
      • As per a study by iCAT, a government testing agency, SHEVs can run 40% of the distance and 60% of the time as an EV with the petrol engine shut off.

    Regenerative Braking System (RBS)

    • Based on the type of RBS, the energy recovery happens in multiple ways. 
      • A kinetic system can recover the energy lost during braking and then use this energy to recharge the high-voltage battery of the vehicle. 
      • An electric system generates electricity through a motor during sudden braking. 
      • A hydraulic system uses pressurised tanks to store the vehicle’s kinetic energy and can offer a high energy recovery rate which is ideal for heavy vehicles.
    • Advantages in Automotive Applications:
      • Better braking efficiency in stop-and-go traffic which enhances fuel economy;
      • Aids in reducing carbon emissions
      • the extended range of batteries; and
      • Helps in energy optimisation resulting in minimum energy wastage.
    • While RBS are already available in most EVs, the technology is also used in electric railways


    Main Advantages

    • Fuel Efficiency: Most vehicles with hybrid technology offer better fuel efficiency, more power, and minimum emissions. 
    • Increased Mileage: The design of hybrid vehicles for reduced engine size and car weight as compared to ICE vehicles, translates into increased mileage to favour the demand for these vehicles. 
    • Instant Torque: With the increase in total power and torque, HEVs can deliver instant torque and provide high torque even at low speeds.
    • Auto Industry Transition: 
      • The automotive industry is transitioning, with an increasing focus on hybrid and battery electric vehicles (BEVs or EVs). 
      • The rise in fossil fuel prices, increase in the adoption of clean mobility solutions, and stringent government norms for emission control are driving the growth of the EV market.

    Challenges for Hybrid Technology

    • Higher Cost: 
      • In a price-sensitive market like India, one of the major challenges for HEVs is the high vehicle cost. 
      • Battery 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.
    • Lack of Infrastructure: India’s road to a fully-electric ecosystem still has a few hurdles – inadequate infrastructure, lack of high performing EVs .
    • Robust Manufacturing Ecosystem: The absence of a robust manufacturing ecosystem for the materials associated with the EV revolution, coupled with the concentration of the supply chain in certain regions.


    • SHEVs will play a critical role not only in reducing fossil fuel consumption, carbon emissions and pollution but also in creating a local EV parts manufacturing ecosystem.
    • HEVs protect the huge existing investments and jobs related to ICE parts manufacturing thus ensuring a faster and disruption-free technology transition.
    • SHEV adoption will also accelerate BEV (Battery EV) adoption as these technologies have common electric powertrain parts that will help in aggregation of demand at parts level for local manufacturing, thereby helping in reducing cost for SHEVs and BEVs to create a viable ecosystem for electrified vehicles.

    Source: TH