Author: Marion Hanson

Diesel engines are an essential part of the fleet industry, allowing your fleet vehicles to travel to and from different destinations safely and smoothly.

Reliance upon fossil fuels first arose out of necessity. When first invented it was the best method of fuel that was available at the time.

When was diesel invented?

In the 19th century, in particular, the oil was made out of whale oil which had terrifying effects on ocean life. Luckily, in 1854 a cleaner-burning, more abundant and easier-to-produce alternative was invented, this fuel was also easier to produce and was made by Canadian geologist Abraham Pineo Gesner through the distillation of crude oil, making it better for the environment than the original fuel.

From there on, further petroleum products were manufactured such as petrol and lubricants to serve industry (including fleet vehicle) needs.

What are diesel engines?

Diesel engines are a type of internal combustion engine which presents across multiple applications, including fleet vehicles. It can also be used to generate heat and electricity.

Diesel fuel is named after the diesel engine for which it is manufactured, not the other way around. It got its name from the inventor, Rudolf Diesel.

What is the difference between diesel and petrol?

Diesel engines differ from petrol engines in that they operate in a compression ignition engine. This means that they use high pressure to combust it’s fuel, instead of an ignition source (with petrol engines being fired up by a spark)

Another key difference is the fact that diesel is heavier than gasoline, this means that it evaporates slower whilst emitting fewer amounts of CO2 and methane, but unfortunately producing higher levels of nitrogen compounds in the process.

How much is diesel per litre?

The average diesel price in the UK in August 2024 is 152.79p per litre as of the latest update by the RAC. Whereas, this can fluctuate on a day-to-day basis based on industrial events.

How many miles per litre of diesel?

The number of miles you can get per litre of diesel depends on various factors, including the type of vehicle, driving conditions, and driving habits. However, on average:

Small to medium diesel cars

Typically achieve between 15 to 20 miles per litre (mpg equivalent of 68-90 mpg).

Larger diesel vehicles (e.g., SUVs):

Usually get around 10 to 15 miles per litre (mpg equivalent of 45-68 mpg).

These figures can vary based on factors such as highway vs. city driving, vehicle maintenance, and load. For more accurate data, you should check the specific fuel efficiency ratings for your vehicle model.

 

Benefits vs considerations of diesel

Benefits of diesel

Diesel has got great mileage, with 25 to 30 percent better fuel economy than similar-performing gasoline engines. This is due to it being the most efficient and energy-dense fuel available as it contains more usable energy than gasoline.

Another benefit is that diesel contains no spark plugs or distributors, meaning that it will never need ignition tune-ups.

When it comes to diesel engines, they are built to withstand the rigors of higher compression. They usually last much longer than gas-powered vehicles as a result of this, meaning they will require fewer major repairs in this department.

Storing this fuel is efficient due to it being able to be kept stable at natural temperatures and operable for most temperatures experienced throughout the year.

Considerations of diesel

As with all benefits also come some considerations to think about, particularly regarding sustainability factors. This is because diesel produces high levels of emissions. This has particularly become prominent in recent years and has led to the rise in popularity of electric vehicles (EVs), but it is important to remember that even EV vehicles have compromises of their own.

Non-renewable, air-polluting options can be blended with renewable drop-ins to eliminate this issue, this also helps with the downside of oil drilling to extract fossil fuels that make this diesel and any toxicity to the environment.

NOx content and sulphur can also be present in some diesel meaning that only buying high-quality diesel which meets Euro VI standards and is ULSD certified is crucial.

FAME content means diesel is hygroscopic (meaning it attracts water) and results in clogged filters and engine breakages (FAME-free alternatives do not have this issue)

 

Diesel petrol fleet uses

Whilst diesel is usually associated with passenger cars, it can also be used to power machinery in the construction industry.

Some of these vehicles include vans, lorries, buses, coaches, tractors, harvesters, cranes, bulldozers, diggers, forklifts and rail transport.

 

Fuels that can be used in diesel engines

Different types of diesel fuels have been authorised to be used within different diesel engines, these include:

What is red diesel (gas oil)

Red diesel fuel is used in off-road vehicles and machinery. Although it is the same as regular diesel, it is marked with a red marker (dye) to prevent illegal use on road-going vehicles.

Paraffinic diesel (such as HVO fuel or GTL fuel)

Paraffinic diesel usually has a very high cetane number with no sulfur, nitrogen, oxygen or aromatics included. Paraffins can be produced with various processes from either fossil fuels or neweable feedstocks. Alternatively, synthetic fuels are produced by gasification and Fischer-Tropsch (FT) which is the liquefaction of natural gas (GTL) and coal (CTL).

Biodiesel

Biodiesel is a renewable, biodegradable fuel manufactured domestically from either vegetable oils, animal fats or recycled restaurant grease. Biodiesel meets both the biomass-based diesel and overall advanced biofuel requirements of the Renewable Fuel Standard.

These different types of diesel are all produced to meet different specifications that are intended for that specific type of fuel. Before switching to any alternative fuel you should always check your engine’s warranty to ensure it covers alternative fuels.

 

How does diesel fuel work?

Diesel engines have a wide range of applications, but the basic operation is largely consistent, as most are four-stroke engines. This means power is generated through a series of four stages (stroke cycles), which we will explain below.

Before the engine begins operating, fuel is pumped from the tank to the engine. The fuel passes through a filter that removes any contaminants—like bugs, dirt, or, in cold conditions, waxed FAME biodiesel, which can cause significant issues during winter. To assist farmers, refineries sometimes reduce the 7% biodiesel content in red diesel used in agriculture during colder months.

Stroke 1: Intake stroke

The fuel injection system delivers the correct amount of fuel, which is mixed with air in the pistons. This mixture is then compressed.

Stroke 2: Compression stroke

The intake valve closes, and the mixture of air and fuel is compressed within the cylinder.

Stroke 3: Combustion stroke

Under high pressure, the air-fuel mixture ignites, leading to combustion and the release of energy.

Stroke 4: Exhaust stroke

The exhaust gases from combustion are expelled through the exhaust valves, pass through the exhaust manifold, and enter the turbine side of the turbocharger.

Turbocharger

After the exhaust strokes, the remaining fuel fumes are sent through to the turbocharger. This component pressurises air into the cylinder which goes on to increase oxygen content which results in a better burn. This turbocharging process can increase the power of a diesel vehicle up by 50%, whilst also reducing the engine’s fuel consumption by 25%.

 

Emission reduction in diesel engines

Since 2015, diesel engines must meet specific standards to ensure minimal impact on the environment. To ensure this specific regulations must be adhered to.

Exhaust Gas Recirculation (EGR)

The EGR system is designed to reduce pollutants, particularly NOx emissions, from the exhaust.

Diesel Oxidation Catalyst (DOC)

The DOC converts unburnt fuel into CO2, preventing hydrocarbons from being released into the atmosphere.

Diesel Particulate Filter (DPF)

The DPF reduces particulate matter (smoke) in the exhaust fumes, ensuring the exhaust gases are as clean and environmentally friendly as possible according to Euro 6 standards.

Selective Catalytic Reduction (SCR)

In modern Euro 6 diesel engines, exhaust fumes pass through the SCR system, where harmful emissions are reduced using diesel exhaust fluid (AUS 32, commonly known as AdBlue). The SCR catalyst combines the exhaust fumes with AdBlue, converting NOx particles into ammonia (NH3) and water, which are then expelled through the exhaust. It is crucial to use AdBlue that meets ISO 22241 standards to prevent potential damage to the engine from contaminants.

 

Diesel engine maintenance

Diesel engines are known for their durability and long lifespan when properly maintained. To achieve this longevity, regular maintenance is essential, including servicing the engine components, replacing fluids and diesel engine oils that provide lubrication and cooling, and using high-performance fuels.

 

How far can you drive with petrol in a diesel car?

Driving with petrol in a diesel car can cause serious damage, and how far you can drive before issues arise depends on various factors, such as the amount of petrol added and the type of engine. However, it is generally advised not to drive at all if you realise the mistake.

If a small amount of petrol (less than 5-10% of the tank) has been added, and you start the engine, you might be able to drive a short distance—typically a few miles—before the engine starts showing signs of trouble, such as misfiring, loss of power, or stalling. In more severe cases or with a higher concentration of petrol, damage can occur almost immediately, affecting the fuel pump, injectors, and other engine components.

If you’ve added petrol to a diesel car, it’s best to stop the vehicle immediately, avoid starting the engine, and seek professional help to drain the contaminated fuel and prevent damage.

 

Manage your company diesel with a fuel card

Fuel Card Services work with major fuel brands to offer you competitive fuel prices that can help to save your business money when it comes to refilling your fleet vehicles with fuel.

To enquire about how these fuel cards could help your business, contact our helpful team today.

As the shift toward electric vehicles gains momentum, we understand that your business needs to carefully consider the timing and method of transitioning to an electric fleet. This decision involves more than just financial factors; it also requires consideration of driver preferences, the feasibility of implementing EV charging infrastructure, and the administrative challenges of updating your fleet.

Given these complexities, we recognise that electric vehicles may not be the best fit for every new addition to your fleet. That’s why it’s important to explore other available fuel options. This comprehensive guide on petrol will help you make an informed decision about the most suitable fuel type for your business.

What is petrol?

In this section, we will discuss what the different types of petrol are and which are the best suited to different types of fleet vehicles or situations.

What is E5 petrol?

E5 petrol is a type of unleaded petrol that contains up to 5% ethanol, a renewable biofuel made from plant materials like sugarcane or corn. The “E” in E5 stands for ethanol, and the “5” indicates the percentage of ethanol mixed with the petrol.

What is E10 petrol?

E10 petrol is a type of unleaded petrol that contains up to 10% ethanol, a renewable biofuel made from plant materials such as corn or sugarcane. The “E” in E10 stands for ethanol, and the “10” indicates the percentage of ethanol mixed with the petrol.

E10 contains a higher percentage of ethanol compared to E5, which has up to 5% ethanol. This makes E10 slightly more renewable and potentially less harmful to the environment because ethanol produces fewer carbon emissions when burned compared to pure petrol.

 

Benefits of petrol fleet vehicles

Cost efficiency

If your drivers use fuel cards, this could result in lower overall fuel costs for your business.

Petrol vehicles also typically have a lower purchase price compared to diesel, electric, and hybrid models. Whether you’re buying the vehicle outright or through a contract purchase or hire agreement, this often translates to lower upfront costs or reduced monthly payments.

How much is petrol per litre?

As of now, the average price of petrol in the UK is £1.47 per litre according to the RAC. This can vary on a day-to-day basis depending on your location and the specific petrol station you visit, but this is the current national average.

 

How many miles per litre of petrol?

The number of miles per litre of petrol (MPL) can vary significantly depending on different factors, including the type of vehicle, driving conditions, and driving habits. With our mileage counter, you will be able to see how many miles your fleet vehicles are doing in a typical day, as well as other interesting insights.

Fuel efficiency for typical cars

The average fuel efficiency for cars in the UK is around 10 to 15 miles per litre (MPL). Smaller, more efficient vehicles, such as city cars or hybrids, can achieve closer to 15-20 MPL, while larger vehicles like SUVs might be closer to 8-12 MPL.

Factors Impacting Efficiency

Driving at higher speeds, carrying heavy loads, frequent stop-and-go driving, and poor vehicle maintenance can all reduce fuel efficiency while driving smoothly at moderate speeds on motorways can increase it.

 

Reduced emissions

While petrol vehicles emit fewer pollutants overall than diesel, incorporating petrol models into a predominantly diesel fleet could help lower your business’s overall emissions.

Considerations for petrol fleet vehicles

While petrol vehicles offer some benefits, they also have potential considerations:

Fuel efficiency

Petrol vehicles are often less fuel-efficient than other types of fuel, which can impact your fuel expenses, particularly if your drivers are less economical in their driving habits. This may warrant additional training to improve fuel efficiency.

Higher CO2 emissions

Petrol engines emit more CO2 per mile compared to other fuel types, which could result in higher penalties, such as increased Benefit-in-Kind (BIK) rates or higher company car tax contributions.

E5 and E10 fuel considerations

Recent changes to standard petrol options at fuel stations mean that E10, which contains up to 10% renewable ethanol, is now the default choice, replacing E5 with 5% ethanol.

This shift is part of an effort to reduce the environmental impact of petrol. However, it’s important to check the compatibility of older vehicles in your fleet with E10 fuel.

Is E10 harmful to vehicles?

Most modern vehicles can safely use E10 petrol. However, older models may experience issues due to the higher bioethanol content, which can be corrosive to certain components and potentially cause engine damage or blockages. Additionally, there might be a slight decrease in fuel efficiency when switching from E5 to E10, particularly in vehicles with smaller engines.

The value of premium petrol

Premium petrol, which remains an E5 blend, is recommended for vehicles that are not compatible with E10.

For drivers who prioritise fuel economy or those with older vehicles, using premium petrol can offer more mileage despite its higher cost.

Which petrol is best for your fleet

The best petrol option for your fleet depends on your fuel use priorities. E10 is widely available and more affordable, while E5 offers better fuel efficiency and a higher octane content, which can further enhance performance.

Mixing premium and super unleaded petrol

You can safely mix premium and super unleaded petrol in the same tank, allowing flexibility across your fleet without needing to assign specific fuel types to particular vehicles.

Deciding if petrol is right for your fleet

Regularly reviewing your fleet procurement policies and considering the fuel type for each new vehicle is crucial from a sustainability and cost angle. We recommend weighing the pros and cons of petrol, as outlined above, and comparing it with other fuel options to make the best choice for your fleet. Our guides on petrol vs. diesel, as well as hybrid and electric vehicles, can assist you in this decision-making process.

 

Manage your company petrol with a fuel card

Fuel Card Services work with major fuel brands to offer you competitive fuel prices that can help to save your business money when it comes to refilling your fleet vehicles with fuel.

To enquire about how fuel cards could help your business, contact our helpful team today.

If you manage a variety of fleet vehicles within the UK, ensuring compliance with drivers’ hours regulations is crucial.

These rules govern driver rest periods and working hours to promote safety and prevent fatigue, with non-compliance leading to significant penalties.

Our guide simplifies some of the more intricate rules to help you better understand your obligations.

What is a working time directive?

Drivers’ hours regulations are designed to enhance driver well-being and improve road safety. Commercial vehicles are required by law to be equipped with tachographs, which record data such as driving time and distance.

All commercial bus and truck drivers must have a tachograph driver card, which stores critical compliance-related data, including rest and break periods. These regulations ensure fair competition among transport companies and help prevent driver fatigue.

European working time directive: Working hours for fleet drivers?

According to the UK’s Working Time Regulations 1998, drivers must receive “adequate rest,” although the specific duration is not defined. However, there are strict rules on driving hours and working times, these rules are below:

• Drivers are limited to a maximum of 10 hours of driving and 11 hours of duty within a 24-hour workday.
• The 11-hour duty limit does not apply if drivers spend between 0 to 4 hours driving each day of the week.
• Certain drivers, such as doctors and service workers, are exempt from the 11-hour duty rule, but the maximum driving hours still apply.
• When operating vehicles in the UK that do not have a tachograph installed, drivers must maintain a written record of their hours. Detailed information is available on the UK government’s website.

Compliance with the EU working time directive in the UK

Even post-Brexit, your fleet may need to adhere to EU drivers’ hours regulations and tachograph requirements, especially for vehicles weighing more than 3.5 tonnes that travel within the UK or to, from, or through EU countries.

EU rules dictate maximum driving times and mandatory rest periods to ensure safety.

To remain compliant, fleet managers must regularly download and analyse tachograph data—every 28 days for drivers and every 90 days for vehicles.

EU regulations under Regulation (EC) No 561/2006

• A daily driving limit of 9 hours, extendable to 10 hours no more than twice a week.
• A weekly driving limit of 56 hours, with a maximum of 90 hours over two consecutive weeks.
• A mandatory rest period of at least 45 hours each week, starting no later than six days after the previous rest period.

What is classed as work during these hours?

Working time includes any activity for which drivers are paid, such as attending training sessions, performing administrative tasks, loading and unloading vehicles, and conducting vehicle maintenance. Essentially, any time when drivers are unable to freely manage their own time is considered working time.

How many hours can I work if I opt-out of the working time directive?

If you choose to opt out of the Working Time Directive in the UK, you are not limited to the standard 48-hour maximum weekly working time. However, there are still important considerations and legal requirements to keep in mind:

Agreement

You must formally agree to opt out of the 48-hour limit, usually by signing an opt-out agreement with your employer. This agreement should specify that you are voluntarily choosing to work more than 48 hours per week.

Health and safety

Even if you opt-out, your employer is still responsible for ensuring your health and safety. This means that they should not require you to work excessive hours that could pose a risk to your well-being.

Rest breaks

The opt-out does not affect your entitlement to rest breaks. You are still entitled to a minimum of 11 hours of rest between workdays and at least one uninterrupted 24-hour rest period per week (or 48 hours every two weeks).

 

Review and withdrawal

You can opt back into the 48-hour limit at any time, even after initially opting out. To do this, you must give your employer at least 7 days’ notice (or a longer period if specified in your agreement).

While opting out allows you to work more than 48 hours per week, it’s crucial to consider the potential impact on your health, work-life balance, and overall well-being before agreeing to anything.

Working time directive for HGV drivers

These regulations apply to many haulage operators and drivers of heavy goods vehicles (HGVs) over 3.5 tonnes, especially those operating within or travelling to, from, or through EU countries. Exceptions in the UK include vehicles used by the military, police, and fire services.

What are digital tachographs?

Digital tachographs are essential for fleet managers to ensure compliance with drivers’ hours regulations. These devices collect a wide range of data, from vehicle registration numbers to driver activities, including incidents like speeding or driving without a driver card.

How often do you download digital tachographs?

Regularly downloading and analysing this data is crucial—at least every 28 days for drivers and every 90 days for vehicles.

Consequences of non-compliance to the UK working time directive

Failure to comply with driver’s hours regulations can result in fines, imprisonment, or revocation of an operating license. Accountability can extend to companies, fleet managers, drivers, and even scheduling personnel if work is not properly organised or if standard checks are not conducted.

 

Ensuring a compliant working time directive with Fuel Card Services

Our award-winning fleet management software is user-friendly, featuring a flexible interface that provides reliable structure and support.

This software allows fleet drivers to easily track their hours seamlessly, and for fleet management to check these hours to ensure these hours align with current working time directive laws.

For further information and queries about this software, please contact our helpful team.