Understand PHEV's meaning with electric cars

If you buy a PHEV, meaning you want to do your bit for the environment, then it will be worth understanding exactly what is being referred to by this term. PHEV cars use a distinct type of technology, although different manufacturers put their own particular stamps on it.

To be clear, PHEV stands for plug-in hybrid electric vehicle.

Therefore, you can find PHEV vans, lorries, and even scooters nowadays, not just cars. In this guide to understanding what PHEV means, we'll be focussing on cars. That said, much of the plug-in technology you will learn about could equally be applied to other sorts of vehicles you'll find every day making their way on Irish roads. Read on to find out what is meant by the term PHEV.

To begin with, it will be worth understanding what is meant by the term hybrid when it comes to cars and other types of transportation. Ever since the invention of the internal combustion engine, there have been two rival systems that most carmakers have used for their vehicles. The first is the petrol-powered engine, and the other is the diesel-powered motor. Although the mechanics involved with both of these sorts of technologies are different – this is something you can tell from just looking under the bonnet of either sort of car – they both rely on fossil fuels being burnt inside a chamber to force a piston outwards. In turn, this is converted into rotational force, something that can be used to turn the wheels of the vehicle concerned.

When it comes to hybrid vehicles, an additional engine and fuel source is included alongside the aforementioned internal combustion engine. Although both diesel and petrol engines could, in theory, be supported by electrical motors, the truth is that hardly any car manufacturers combine hybrid technology with diesel-powered vehicles, which are, by and large, being phased out.

The practical reality, therefore, is that any hybrid car you might consider buying today will have a petrol engine as well as an electrically powered motor inside. Given that such cars blend the two types of technology, often almost seamlessly, they are referred to as hybrids. This means they are a distinctly different category of cars compared to all-electric vehicles, for example.

Does PHEV's meaning cover mild hybrid technology, too?

Now you know what a hybrid car is – one that has a petrol engine and an electrical motor – it will be helpful to understand that there are two types of hybrid technologies on the market. One is called mild hybrid, or MHEV, while the other is the one we're interested in, PHEV. Many people use the term hybrid to refer to both types of technology, but you should note that PHEV's meaning is very different from MHEV even though they're both hybrids. The principal distinction between the two is that you plug a PHEV car into the mains to charge up its battery pack, but you don't ever do this with a mild hybrid.

For clarity's sake, both MHEV and PHEV cars have batteries. They can run on their battery power without needing to use the petrol engine in most cases, and they can both be recharged. They can also both run on their petrol motor so long as there is sufficient fuel in the tank, of course. The important distinction to note, however, is that a PHEV car will often have a much bigger battery capacity. As such, you need to charge it up when it is not in use to keep it topped up. MHEVs tend to have smaller batteries that recharge when the car is braking or going downhill, capturing unused energy and storing it for later use. Although many PHEV cars also make use of such regenerative energy, the main difference is they also take power from the mains.

Comparing PHEV and MHEV car technologies

The main advantage of owning a PHEV compared to an MHEV is that you can travel further on all-electric power. Because the battery pack is larger, you get a longer range before the petrol engine needs to kick in and take over. When using both electrical power and petrol power, PHEVs offer superior fuel efficiency for the same reason. Basically, they keep going for longer journeys than MHEVs can manage. However, there is a cost involved when you charge a PHEV from the mains, something that is not the case with an MHEV car. However, since electricity is generally cheaper than petrol, this is not much of a setback. Furthermore, the greater use of electric power in a plug-in hybrid car compared to a mild hybrid one means that there will be fewer emissions for every mile driven, something that is especially important if you live and work in an urban environment, such as Dublin.

How do PHEV cars actually work?

Although it is important to understand the meaning of PHEV by comparing it to the other automotive technologies available today, getting to grips with how a plug-in hybrid car works is also a good idea. All PHEVs have a battery pack that is distributed around the car to keep the vehicle balanced. The elements of the pack are connected together with insulated wiring. When the car is running on petrol alone, there is no electrical draw placed on the batteries. Indeed, they may even be charged up by the aforementioned regenerative charging systems in use today. However, when the car is in electric mode, power will be sent to a second, electrical motor that will turn the car's wheels. Electric motors spin rather than use pistons, so they are theoretically more efficient than fossil-fuel-powered engines.

What's more, electric motors don't need lots of gearing to work and produce high levels of torque even when the car is pulling away. As such, nearly all PHEV cars are automatics with no need for a conventional gearbox. Once the battery has run down to zero, the petrol engine can take over without needing to stop. In fact, most modern PHEVs made in the last few years will blend the electrical motor's power with that of the petrol engine. This way, you get the optimal performance level from each. In sports mode, both engines combine for the top output, while in eco-mode, the use of the petrol engine will be limited to get the best out of the sustainable electrical power.

When you run out of battery power driving a PHEV car, you will need to top up. Most people who own a PHEV will invest in a wallbox. This means being able to charge the batteries of the car at a higher level of voltage than is usual. It means the batteries can be charged more efficiently and quicker, too. Although charging via a three-pin plug socket is perfectly possible, this will often take more than a few hours. When fully charged, a typical PHEV offers a range of about 30 miles purely on electrical power before the petrol engine would need to kick in.

Would owning a PHEV mean I’m doing my bit for the environment?

Put simply, yes: it would. This is why the market for new and used PHEV cars has expanded so much in recent years. There are several environmental benefits of driving a PHEV compared to a petrol or diesel-powered car. The first is that electricity is not necessarily made from fossil fuels. Much of it is generated from sustainable means, such as solar panels or wind turbines. As such, using electricity for transport is better than burning fossil fuels in a combustion engine. In addition, PHEVs produce a fraction of the emissions that fossil fuel-powered cars do.

When they are running on their battery power alone, they produce none. In addition, there is another – often overlooked – environmental benefit of PHEVs and other electric vehicles. This is because when they're running on their electrical motor, they don't produce much noise either. Noise from car engines is a pollutant of sorts, so buying a PHEV will also be good for your neighbours as they won't hear you starting up in the mornings so often, if at all.

Comparing PHEV cars to all-electric vehicles

In many ways, the case for owning a PHEV makes itself until you compare a plug-in hybrid to an all-electric car. The latter has the longest range and doesn't rely on fossil fuels at all. However, despite the fact that there are more public charging stations for plug-in cars than there ever used to be, many motorists like the idea that a PHEV allows them to refuel either with petrol or electricity, thereby affording them more flexibility with their travel arrangements.

Often PHEVs are a good bit more affordable than all-electric cars, too.