Toyota’s flex-fuel prototype: How it will work, what advantages it offers

Subject: Environment

Section: Pollution

Context:

Toyota unveiled a prototype of the Innova Hycross with a flex-fuel hybrid powertrain, its first car in India with this option, and one that the Japanese carmaker claims is the world’s first BS6 Stage II-compliant flex-fuel vehicle.

Details:

Toyota had displayed an imported Corolla flex-fuel hybrid sedan as a pilot project late last year.
It was part of a government-led push to commercially deploy this technology, which is already in use in markets such as Brazil, Canada, and the United States.

Hycross prototype

The Hycross flex-fuel prototype has a 2-litre Atkinson Cycle petrol engine coupled with an electric motor.
Toyota claims the prototype
- Can run on petrol with more than 20% ethanol blending that is currently mandated in India
- Its performance would be at par with the standard Hycross hybrid, even with ethanol-blended petrol.
- It will achieve low carbon emissions on a comprehensive well-to-wheel basis.
The Hycross flex-fuel prototype would run 60% of the time in the electric vehicle mode using energy stored in the battery pack.
The next steps include:
- Further finer calibration,
- Homologation (process of certifying that a vehicle is roadworthy), and
- certification.

Flex-fuel technology

A flex-fuel vehicle typically has an internal combustion engine (ICE) but it can run on more than one type of fuel, or a mixture of these fuels.
The most common versions use a blend of petrol and ethanol or methanol.
This is made possible by equipping the engine with a fuel mix sensor and an engine control module (ECM) programming that senses and automatically adjusts for any ratio of designated fuels.

How these cars work

Most components in a flex fuel vehicle are the same as those in petrol-only cars. But some special ethanol-compatible components are required to adjust to the different chemical properties and energy content in ethanol/ methanol, such as modifications to the fuel pump and fuel injection system.
The ECM is calibrated to accommodate the higher oxygen content of ethanol.
The hybrid engine would have separate spark plugs, piston ring tops, and valves to render them more corrosion-resistant, and a modified catalyst in the exhaust system to lower hydrocarbon emissions.
The vehicle’s fuel filter and fuel lines have also been tweaked.
According to IHS Markit, as of 2018, there were more than 21 million flex-fuel vehicles in the US, but Brazil was the biggest market and leader in this segment.

Flex pros and cons

Pros:
- Sharply lowers harmful pollutants such as carbon monoxide, sulphur, and carbon and nitrogen oxides.
- Help cut oil imports to fuel vehicles.
- However, flex-fuel cars typically take a 4-8% hit on fuel efficiency when using ethanol for motive power.
- Improved acceleration performance.
Cons:
- Lower fuel efficiency
- Source crops such as sugarcane are usually very water-intensive.
- According to a NITI Aayog report, in 2019-20, more than 90% of the ethanol produced in the country came from sugarcane, which is also a politically important crop in states such as Maharashtra and Uttar Pradesh.

Blending advantages

The ethanol mix in petrol in India went up from 1.53% in 2013-14 to 11.5% in March 2023.
This has helped cut the oil import bill by an estimated Rs 41,500 crore in the last eight years.
In 2020-21, ethanol blending enabled a reduction of 26 million barrels of petrol, resulting in savings of Rs 10,000 crore.
The expected implementation of E20 by April 2025 is estimated to result in annual savings of Rs 35,000 crore in India’s oil import bill.
To overcome the challenges of lower fuel efficiency of flex-fuel vehicles, electrified flex-fuel vehicles are being introduced, which offer the advantages of both a flex-fuel engine and an electric powertrain, as in the case with the Hycross prototype.