As the name suggests, mild hybrid cars are a gentle version of self-charging or plug-in hybrid electric vehicles. Unlike their hybrid cousins, most mild hybrids can’t be driven by electricity alone, but rather use an electrical system to boost additional horsepower in either a petrol or diesel engine.
The technology in mild hybrid vehicles make them a popular choice for eco-conscious motorists who value improved fuel economy, lower CO2 emissions, and enhanced performance, but who can’t afford the charging set-up of a plug-in hybrid or all-electric car. Such is the growing demand for mild hybrid cars that most manufacturers now produce models in this form.
Not only can mild hybrid cars offer several benefits over traditional petrol and diesel vehicles like improved fuel efficiency, but they’re also cheaper than any other type of hybrid currently available. This blog will explore the relatively new world of mild hybrid cars, explain how they work, and what makes them a favourite choice with motorists.
What Are Mild Hybrid Cars?
Mild hybrid cars combine a traditional combustion engine with a small electric motor and a 48-volt battery system. Unlike full hybrid or plug-in hybrid vehicles, mild hybrids cannot operate on electric power alone. Instead, their electric motor is designed to assist the internal petrol or diesel combustion engine.
By combining smart technology with an electrical system, mile hybrids reduce CO2 exhaust emissions from a petrol or diesel engine, improve fuel economy, and increase horsepower.
How Do Mild Hybrid Cars Work?
Mild hybrid cars come with an electric motor and small lithium-ion battery pack instead of a traditional starter motor and alternator. The motor – also known as an integrated starter-generator – automatically charges the battery each time you apply the brakes or coast along without touching the accelerator.
The electricity produced is directed to the engine to boost acceleration and provide power for the car’s other electrical components. This, in turn, means less work for the combustion engine, improved fuel economy, lower CO2 emissions, and enhanced performance.
A mild hybrid uses relatively simple technology and runs on a 48-volt electrical system which is higher than the 12-volts found in most traditional combustion engines. Even so, a mild hybrid system offers only light electrical assistance to the petrol or diesel engine. Unlike full or plug-in hybrids, this isn’t enough to drive a vehicle purely on electric power.
As well as being cheaper than other hybrids, mild hybrids provide numerous benefits over standard petrol and diesel vehicles. It’s why a host of major manufacturers like Audi, BMW, Fiat, Ford, Land Rover, Seat, and Volvo all produce models with mild hybrid technology.
What Are The 7 Benefits of Mild Hybrid Cars?
Often an eco-friendly choice for drivers, mild hybrid cars offer greater fuel efficiency, lower CO2 emissions, and enhanced driving performance among their many benefits. They have a lower environmental impact than standard combustion engines and are an ideal solution for anyone looking to reap the rewards of hybrid technology without committing to an all-electric vehicle.
Here are seven key benefits of mild hybrid cars:
1. Better Fuel Economy
Some manufacturers claim mild hybrids boost fuel efficiency by up to 15% when compared to traditional petrol and diesel cars. Others suggest an improvement of 3 to 5mpg is more realistic depending on driving habits and conditions. Whilst dropping up to 5mpg might not seem like a lot, it could mean you pay less VED (vehicle excise duty) tax.
One of the mild hybrid’s tricks is that it shuts off the engine when the car is coasting, which saves on fuel. Not only that, but the engine restarts quicker than a normal motor, providing almost instant power when you accelerate.
2. Enhanced Performance
The electric generator in mild hybrid vehicles may be small, but it packs enough punch to give a car additional power and an acceleration boost when it’s needed. This process improves the overall performance and is a particular advantage when driving around towns and cities and at low speeds. Ford, for example, says customers can expect 20% faster acceleration from their mild hybrid vehicles compared with their non-hybrid options.
3. Lower CO2 Emissions
Features like optimum engine efficiency and start-stop functions result in lower CO2 exhaust emissions in mild hybrid cars than standard petrol or diesel engines. Not only does this help reduce the vehicle’s overall impact on the environment, but it also complies with strict emissions standards that are being introduced in towns and cities such as the Ultra Low Emission Zone (ULEZ) operating in London.
4. Smart Regenerative Braking
When you apply the brakes in a vehicle, energy is produced – mild hybrids recuperate this lost energy and use it to power a battery which delivers torque and boost to the vehicle’s combustion engine. The process results in lower fuel consumption, greater energy efficiency, reduced CO2 emissions, and improved driving performance.
5. Stop-start Efficiency
The stop-start technology in a mild hybrid is ultra-effective. It’s quicker at switching the engine off when the vehicle is stationary, and more efficient when restarting. This system stops fuel being used when idling, cuts out unnecessary exhaust emissions, and saves on fuel consumption.
6. Shut-down Feature
Another fuel-saving feature of the mild hybrid is its ability to shut the engine down when the car is coasting and the accelerator isn’t pressed down. Some models like the Audi Q8 can coast for up to 40 seconds at a time to save fuel. There’s no reason to worry about safety either as the integrated starter-generator can restart the engine quicker than a regular starter motor, so power will be instantly restored the moment you accelerate.
7. Value for Money
Mild hybrids may be marginally more expensive than standard petrol or diesel cars, but they have superior fuel efficiency as well as the potential for lower long-term driving costs and fewer emission penalties. Mild hybrids are also generally less expensive to buy than other types of hybrid and all-electric vehicles.
What are the Disadvantages of Mild Hybrid Cars?
As well as several benefits, mild hybrid cars also have some limitations such as the inability to drive on electric power alone. The disadvantages of mild hybrids include:
- No electric-only range: Most mild hybrids won’t run solely on electric power. The electric motor is there to assist a petrol or diesel engine, so mild hybrids lack the same electric capabilities as plug-in hybrid or electric vehicles.
- Less fuel efficient than plug-in hybrids: Mild hybrids are less fuel efficient than plug-in hybrids as electrical assistance is limited. However, they do provide greater fuel efficiency than petrol or diesel cars.
- Limited CO2 reduction: Mild hybrids produce fewer CO2 exhaust emissions than petrol or diesel cars, but they aren’t as ‘clean’ as plug-in hybrid cars.
- No subsidy schemes: There’s an absence of government subsidy to reduce the purchase price of mild hybrid cars, whereas several schemes are available for plug-in hybrids. You might be able to scrap your older car under a government car scrappage scheme though and get some discount on a mild hybrid.
Are Mild Hybrid Cars Worth It?
This depends on your interpretation of ‘worth it’. If you’re wondering if mild hybrids are cheaper than other hybrids and cleaner to run than petrol and diesel cars, the answer is a definite ‘yes’.
For instance, the Ford Puma combines a mild hybrid system with a 1.0-litre, three-cylinder petrol engine that’s also used in the Kuga, Focus, and Fiesta. Ford claims the system provides an extra 15 lb-ft of pulling power resulting in a 10% saving in fuel economy, and 20% faster acceleration when the engine is under stress or heavy loads.
That said, mild hybrid cars don’t deliver the same level of economic and environmental benefits as plug-in hybrid electric vehicles (PHEVs), and they don’t benefit from the lowest rates of company car tax. However, mild hybrids generally cost less to buy than other hybrids and are still more economical and environmentally friendly than standard petrol and diesel cars.
Another advantage of mild hybrids is that they work with both manual and automatic gearboxes, which is an attractive feature for those wanting a more traditional driving experience. However, other types of hybrid and all-electric vehicles are mostly available as an automatic option only.
While mild hybrid and other hybrid cars are not exempt from road tax in the UK, you’ll still pay a lower tax rate than petrol or diesel vehicles thanks to greater efficiency and lower CO2 emissions. This is another cost-saving that makes mild hybrids an attractive option for motorists.
For motorists who want to minimise their environmental impact while taking advantage of the benefits of hybrid technology without investing in fully electric vehicles, mild hybrids are an accessible and practical option.