Petrol vs. Diesel
In recent years, both petrol and diesel technology has come along a very long way. Diesel cars are no longer the wheezy, noisy machines they used to be, while petrol vehicles have introduced a large number of innovative features to reduce fuel consumption.
Direct injection technology in petrol engines is leading to significant improvements in those vehicles. Modern engines run with much more efficiency, meaning that less fuel is burnt and significantly less un-burnt fuel is transmitted to the exhaust. These systems are most prevalent at high and mid RPM, meaning that a direct injection four stroke petrol engine is very suited to long runs on the motorway, but isn’t particularly suited to stop-start trips around town. This is because the mixture of fuel and air returns to a balance at lower vehicle speeds. Put simply, a small petrol driven car may be very good for trips around town, but a diesel may be more useful for urban journeys and commuting.
Diesel cars, however, have always had a higher level of fuel consumption. Due to the various refinements made to this type of vehicle over the years, it is hard to tell the difference between the two types of engine. Generally speaking, diesel vehicles usually cost more to buy. However, this increase in initial outlay is typically reflected in resale values. The service intervals and service costs are usually equivalent between the two types of engine, although both will require the oil and oil filter changing at least once per year.
It is worth considering that car tax is now based on CO2 emissions: as diesel engines are more efficient than typical petrol engines, the lower car tax can equate to significant savings over the years.
A diesel motor is a very good option for longer journeys and around town. However, if the majority of your mileage is spent in urban areas where there is plenty of traffic, a regular non-direct injection, small petrol engine will usually work out as cheaper to run. A direct injection petrol engine featuring lean burn technology, while sometimes costing more to purchase to begin with, will pay dividends on long motorway commutes and touring holidays.
Hybrid petrol burning vehicles are becoming increasingly popular on the market. These typically have a small petrol engine of around a litre, but also incorporate batteries and an electric motor to reduce the strain on the engine. Whilst hybrid cars still burn petrol, it is worth noting that they do produce fewer emissions and are not eligible for the London congestion charge. The system works by charging the battery through kinetic energy recovery systems that normally draw energy from the excess energy produced under braking. This means that hybrid vehicles are excellent choices for around town and the occasional motorway journey, but for predominant motorway driving, a diesel or direct injection petrol powered vehicle may work out to be the better choice.