There can be distinct advantages when driving a diesel car, hiring one when you visit Spain can mean you make great savings on fuel costs. Although Diesel is a little more expensive than petrol at the pumps it can sometimes produce twice as many miles per gallon in a car when compared to petroleum.

Noisy polluting diesel engines of yesteryear are long gone and buried. The days of driving a diesel car and sounding like the latest John Deere or Massey Ferguson tractor as you popped to the shops are over. Today's modern diesel engines are quiet, far less polluting, economical, and produce far more torque than the equivalent petrol model.

The first diesel engine was designed by a German man named Dr. Rudolph Diesel. It was constructed in 1893 but diesel engines didn't really go into mass production until the 1930s. During this period outdated steam engines were replaced by Diesel engines. They were also introduced into large machinery such as tractors, tanks, trucks and heavy plant, basically any vehicle which required a lot of torque and little maintenance. They were also implemented as static diesel generators used for producing electricity in times of emergency.

During the seventies we saw some of the first instances of Diesel engines being implemented into cars. Since then huge developments have been made in the world of diesel engines. They have been refined, turbo charged to avoid flat spots and made super efficient and quieter. If you are used to driving a diesel you will understand all of the benefits and invariably want them in your hire whilst you are away.

A diesel engine works in much the same way as a petrol engine. It is an internal combustion engine; fuel is ignited to move pistons inside cylinders which in turn move a crank which eventually produces a turning motion. This turning force can then be transmitted to the wheels through a series of gears and prop shafts. The biggest difference is that a diesel engine ignites the fuel alternatively. In a petrol driven engine petroleum is mixed with air to create a fine vapour and then ignited by a spark inside the combustion chamber or cylinder.

A four cylinder diesel engine works by forcing air into a cylinder and allowing the piston to compress it. The diesel is squirted into the cylinder at point when the pressure is just before its highest. As the piston moves back up the cylinder air and diesel are pressurised, which in turn causes the mixture to heat up. Just as the piston reaches the top of its movement they get so hot that they combust forcing the piston back down in the block and continuing the movement of the piston rod and cam which eventually turns the wheels of your car. This cycle is said to be named after Nicolaus Otto, a German engineer.

As a diesel engine relies on compression to form heat and in turn ignite the diesel fuel you can imagine there may be problems when starting a cold engine. Diesel engines have a cold start injector which pumps extra diesel fuel into the engine making it easier to start. The problem still is that the heat generated during compression is dissipated into the cold steel block of the engine rather than igniting the diesel. To over come this, engines are fitted with glow coils these are small metal rods which glow warm when fed with electricity. These draw power from the battery pre heating the cylinders which in turns prevents the heat of compression being stolen by a cold steel engine. Today these are generally found on older engines and larger industrial machinery.

Remember that when you place the key in the diesel ignition there is sometimes a delay when you must wait for the coils to heat up and warm the cylinders before you can start the diesel engine. This is usually indicated by a light on the dashboard. The light indicating the coils will go out once the heat in the coils is sufficient, you can then turn the key and start the ignition.