What are Hybrid Electric Vehicles (HEVs)?

Source: By Chetan Nayak: The Indian Express

Electric vehicles have been increasingly getting popular in India over the past year. Other than the multiple consumer-oriented two wheelers and four wheelers that have launched lately, we have also seen many public transport vehicles like city buses go electric in cities like Mumbai and Delhi.

However, while the electric revolution continues, many issues that stop consumers from getting into electric vehicles or EVs continue to exist. One of these is the lack of a widespread charging infrastructure, which potentially handicaps EV users from taking longer trips to more remote areas. To deal with these issues, brands have been coming up with hybrid electric vehicles (HEVs) – cars that club the benefits of both petrol engines and electric motors, while aiming to negate the cons of both.

In today’s edition of Tech InDepth, we’ll be looking at how exactly these hybrid engines function, how they’re different from conventional electric vehicles as well as other details you should know about if you’re looking at purchasing one of these.

What are Hybrid vehicles?

To understand hybrid vehicles or HEVs, let’s have a quick recap of how petrol and electric vehicles work. Petrol vehicles work on petrol engines and use combustion to power the vehicle. Here, controlled burning of fuel inside the car releases energy in the form of both heat and motion, the latter of which is converted to the spinning of the wheels, via a complex mechanism of pistons, shafts, gears and axles.

In an electric car on the other hand, there is no engine and there are no gears. The power comes from a rechargeable battery, and the vehicle moves with the help of an electric motor. All the energy involved here is electric, which also means there aren’t a lot of moving parts that require regular servicing. However, the battery itself does gradually lose its ability to retain the same amount of charge over time. Also, the range of most EVs available today in India is also limited.

In hybrid vehicles, there are multiple types of mechanisms that power cars. The two most common ones are series-hybrid and parallel hybrid.

Series Hybrid cars

As the name suggests, these cars use an electric motor, connected with a petrol engine in series. In such mechanisms, the combustion engine has no contact with the wheels of the vehicle, except via the electric motor. The working here relies on the petrol engine burning fuel and creating energy, but instead of creating kinetic and heat energy, a generator converts the energy from the petrol engine directly to electricity, which powers the electric motor, giving power to the car.

Most series hybrid vehicles, while they rely on an electric motor, cannot be charged externally like conventional electric cars. They must be fueled, as only the petrol engine can create the power to generate electricity for the electric motor.

These vehicles are great for regions like India, where the infrastructure of electric charging remains scarce. Users still rely on fuel, but end up getting much better efficiency as the converted electric energy is more efficient than the combustion powering the vehicle directly. Additionally, mechanisms are also in place to recharge the electric motor every time you brake, resulting in further savings.

Parallel Hybrid cars

With parallel hybrid cars, there is a common transmission in the vehicle that can pull power from both the electric motor and the fuel engine, both of which are connected in parallel. Such cars can be completely automatic, manual, or even CVT (Continuous Variable Transmission) based on the make and the mode a user drives in.

In such a mechanism, the electric motor itself can only be recharged from regenerative braking, while the fuel you put in the car will power the engine. Since both the motor and the engine can power the wheels, users have more control for when they want to drive efficiently versus when they want more responsive, sporty driving at the cost of fuel efficiency. As a result, wheel power keeps switching between the engine and the motor based on driving conditions.

Parallel hybrid designs are used by a number of brands like Toyota, Hyundai, Ford, Honda, etc. They are also more popular over series hybrid cars majorly for one reason – better performance.

Series Parallel Hybrid cars

While they may not be as common, cars that implement both a series and a parallel hybrid architecture in the same vehicle also exist. These cars, like the Toyota Prius, combine the benefits of a series connection and a hybrid connection.

The wheels can now be powered by both the electric motor and the fuel engine, but power delivery is now in the hands of the user who can choose to power the vehicle completely by the electric motor (series) or the engine (parallel). This works via a power switch that can choose where the wheels get their power from.

Which Hybrid cars are available in India?

While there are not a lot of Hybrid vehicles to choose from in India, manufacturers like Toyota and Honda have already entered the segment with cars like the Toyota Urban Cruiser Hyryder and the Honda City eHEV. Meanwhile, you also have options from brands like Maruti Suzuki, MG Hector and more expensive options from brands like Lexus and Porsche.

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GSLV MkIII lifts India into a new orbit

Source: By TE Raja Simhan: The Business Line

What is ISRO’s GSLV MkIII?

India’s heaviest rocket launcher, GSLV MkIII, is the third-generation rocket from Indian Space Research Organisation (ISRO). The project to develop it was approved in 2002, with a mandate of achieving the capability to launch a four-tonne class satellite to geosynchronous orbit. 

Weighing 641 tonnes, which is equivalent to a large aircraft, GSLV (Geosynchronous Satellite Launch Vehicle) MkIII made its maiden launch on 5 June 2017, from the Satish Dhawan Space Centre in Sriharikota. The launcher is capable of lifting four-tonne class satellites to Geosynchronous Transfer Orbit (GTO) and about 10,000 tonnes to Low Earth Orbit (LEO). The heavy rocket costs around ₹400 crore. In June 2018, the Union Cabinet approved ₹4,338 crore to build 10 such rockets over a five-year period.

What is the rocket’s configuration?

GSLV MkIII is configured as a three-stage vehicle with two solid strap-on motors (S200); one liquid core stage (L110); and a high thrust cryogenic upper stage (C25). The S200 solid motor is among the largest solid boosters in the world with 204 tonnes of solid propellant. The L110 stage uses a twin liquid engine configuration with 115 tonnes of liquid propellant, while the C25 is configured with the fully indigenous high thrust cryogenic engine (CE20) with a propellant loading of 28 tonnes. The overall length of the vehicle is 43.5 m with a gross lift-off weight of 640 tonnes and a 5m-diameter payload fairing. The powerful cryogenic stage enables it to place heavy payloads into LEO of 600 km altitude as was witnessed in the recent launch of 36 satellites of OneWeb.

What are the other launch vehicles that ISRO has?

India has two operational launchers — the workhorse and most reliable launcher Polar Satellite Launch Vehicle (PSLV), and GSLV. The next variant of GSLV is GSLV MkIII.

What is the significance of GSLV-MKIII’s recent launches?

The Chandrayaan-2 spacecraft launched on 22 July 2019, into its planned orbit with a perigee (nearest point to Earth) of 169.7 km and an apogee (farthest point to Earth) of 45,475 km, was a highly complex mission. It represented a significant technological leap compared to the previous missions of ISRO, comprising an Orbiter, Lander and Rover to explore the unexplored South Pole of the Moon. The recent successful launch of OneWeb satellites makes India a cost-effective destination to launch commercial satellites.

What’s the next major target for GSLV Mk-III?

GSLV MkIII is identified as the launch vehicle for Gaganyaan mission, which aims at carrying three crew to LEO and bring them back safely to a predetermined location on Earth.

Where does India stand today in the satellite launch market?

India has over the last two decades built a solid foundation for rocket launches. The ISRO, through its commercial arms, has earned around $279 million (as per July 2022 data) in foreign exchange by launching satellites for global clients. ISRO has been providing launch services for customer satellites since 1999 — more than 350 customer satellites from over 30 countries have been launched by PSLV. With the recent launch of OneWesb, GSLV has made a grand entry into the commercial launch service market for heavier satellites.

What more should ISRO do to become the ‘go to’ player in the satellite launch business?

India has managed to enter the big league of being a cost-effective destination to launch smaller and lighter satellites. The same cannot be said about the heavier communication satellites. GSLV is yet to prove itself as a reliable launcher of heavy satellites. ISRO needs to establish that first. The challenge going forward is to have re-usable rockets that will help in reducing the cost further.