Getting to know vehicle propulsion

With dealerships and car retail businesses opening their doors once again following their recent closure due to the Coronavirus pandemic, this week’s Getting to Know guide focuses on some of the different types of vehicle propulsion available to motorists when buying a car. These span the conventional internal combustion engine to battery power. Each bring their own advantages and disadvantages, and also have an impact on the overall cost of purchase and ownership.


Cars with an internal combustion engine (ICE)


In this case, we are talking about a ‘traditional’ petrol or diesel-powered car that has an internal combustion engine or ICE only. The wheels are therefore not driven by electric motors, as seen in an electric vehicle (EV) or a hybrid.


Some of the benefits:


  • The ability to cover long distances without range anxiety (as seen with an EV)
  • Consumers generally have a greater range of more affordable models versus alternatively fuelled vehicles
  • A choice of manual and automatic gearboxes are available
  • There’s no need for the installation of a domestic charging point
  • A fast refuelling time versus having to recharge a battery in an EV or plug-in hybrid
  • Petrol stations are plentiful across the UK
  • May suit some car buyers who prefer a traditional power configuration and are not yet ready for / or can afford to buy a hybrid or EV


Some of the disadvantages:


  • CO2 emissions can be high for larger-sized engines and can prove more expensive for road tax (VED)
  • No option for zero emission motoring
  • The cost of petrol or diesel at the pumps fluctuates, so running costs will vary
  • More maintenance is required than an EV due to a greater number of moving parts and on-board fluids that need replenishing (e.g. oil)
  • Cars with an ICE are generally more noisy than those that can run on electric power only
  • They are less quiet on start-up than an electric or hybrid car, which may be a consideration when parking and driving in residential areas


Self-charging hybrids / non-plug-in hybrids / full hybrids


Self-charging, non-plug-in, or full hybrids combine an engine, a battery and one or more electric motors. Some of the engine’s power, in addition to energy recovered from braking, is used to replenish the battery, which in turn drives the electric motor(s) and the car at low speeds (e.g. around town / when in traffic) or when accelerating. This type of car does not need to be plugged into an external power source to replenish the battery, as this is all done automatically when on the move.


Some of the benefits:


  • Lower running costs and emissions than an equivalent model powered solely by an ICE
  • The car can run on electric power at low speeds
  • They are available with a petrol or diesel engine subject to the available product line-up
  • No external charging point or cable is required to replenish the battery
  • They are quieter than a pure petrol or diesel equivalent on start-up
  • The ability to cover long distances before needing to refuel

Some of the disadvantages:


  • They can be more expensive to buy than a pure petrol or diesel equivalent, but can be cheaper to purchase than a comparable plug-in hybrid
  • They are not exempt from road tax (VED)
  • The battery can only be charged when the car is in use, rather than being at the vehicle owner’s discretion (i.e. when plugged into a charging point like a PHEV or EV)
  • Self-charging hybrids cannot cover longer distances solely on electric power
  • They are not currently available with a traditional manual gearbox/transmission
  • Batteries can reduce the capacity of the boot


Plug-in hybrids (PHEVs)


A plug-in hybrid or a plug-in hybrid electric vehicle (PHEV) combines a petrol or diesel engine with one or more electric motors, but a larger capacity battery means that it can run on electric power only for much greater distances than a full hybrid. It is called a plug-in hybrid or PHEV, as the battery can be charged via an external source.

Once the battery power has been used up, the car will also then act like a standard petrol or diesel-powered vehicle and be driven solely by the engine. When buying a plug-in hybrid (PHEV), it’s worth checking what type of charging cable the car comes with as standard or as an optional extra, as this will determine how fast the battery is replenished.


Some of the benefits:


  • Compared to a full hybrid, it can be driven for longer distances on battery power only
  • The car can still be driven using the diesel or petrol engine once the electric power has been used up, which is not the case with an electric vehicle
  • Owners have the best of both worlds in terms of being able to drive on electric power in urban areas or for short trips, but still have the ability to cover significant distances using a petrol or diesel engine


Some of the disadvantages:


  • As the name suggests, a plug-in hybrid has to be plugged in to replenish the battery, so a charging cable and charging point is required. This may prove more inconvenient if off-road parking, such as a driveway, is not available, or a charging point is not located in the immediate vicinity
  • It can be more expensive to buy than a full hybrid and is not exempt from road tax
  • Consumers are effectively responsible for replenishing two power sources (i.e. the fuel tank and the battery)
  • The car can weigh more than a pure petrol or diesel equivalent, and may compromise ride quality
  • Plug-in hybrids are not currently available with a conventional manual gearbox/transmission, but a manual mode may still be available for gear changes using paddle shifters behind the steering wheel, for example


Battery electric vehicles (BEVs) / electric vehicles (EVs)



Battery electric vehicles (BEVs) or electric vehicles (EVs) are driven by one or more electric motors that are powered by a battery (usually lithium-ion) that needs to be recharged via an external source when it runs out. An electric vehicle can be front-wheel-drive with an electric motor on the front axle, or all-wheel drive if there is an electric motor on each of the front and rear axles.


Some of the benefits:


  • There’s zero emissions at all times, with no CO2 or NOx impact on the environment when on the move
  • Some models are eligible for the UK Government’s plug-in grant when buying an EV
  • No road tax (VED) is currently due in the first year or during subsequent years of ownership
  • If you have one as a company car, there is a zero percent Benefit-in-Kind tax rate, meaning you pay no company car tax
  • Electric cars will be the only type of vehicle that will qualify for the London Congestion Charge cleaner vehicle discount from 25th October 2021
  • Consumers no longer have to visit a petrol station to refuel and be at the mercy of fluctuating prices
  • There are fewer moving parts than a car powered by an internal combustion engine (ICE), and no oil changes, meaning that there are less components to maintain in comparison. Read our dedicated ‘Getting to Know’ guide on electric vehicle servicing here
  • Customers can order front-wheel-drive (FWD), rear-wheel-drive (RWD) and all-wheel-drive (AWD) models
  • Fast acceleration due to instant torque from electric motors
  • A quiet driving experience compared to a car that has a petrol or diesel engine only


Some of the disadvantages:


  • Electric vehicles can be more expensive to buy than traditional petrol and diesel-powered cars
  • They are generally more costly to insure than other types of cars due to the specialist nature of repairs and the higher cost of parts, although they are fewer components than in cars with an engine. However, overall, when you consider a vehicle’s ‘Total Cost of Ownership’, an EV is much cheaper to run
  • No manual transmission is available if consumers like to be in control of gear changes
  • Range anxiety (i.e. the fear of running out of battery power before reaching a destination)
  • Having to wait for the car to charge versus the shorter time it takes to refuel
  • They are dependent on electric charging points functioning and being available when needing to recharge, especially if consumers have no off-street parking
  • A domestic charging point may be required, which may incur additional costs at the start of electric vehicle (EV) ownership

Please note that The Motor Ombudsman is unable to recommend which type of car to purchase, or advise on suppliers of domestic electric charging points.