What Causes High Fuel Consumption in Petrol Engines
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Vehicles with petrol engines are well known for their performance and fuel-hungry tendencies if they’re not managed properly. Understanding what causes high fuel consumption is the first step in better fuel management.
Get an understanding of what causes high fuel consumption
See the difference between petrol and diesel engines and how it impacts your fuel usage
See how fuel consumption influences your business operations
Get tips on how to reduce your fleet’s fuel consumption
Get an understanding of how telematics might influence your fuel consumption
The causes of high fuel consumption in petrol engines
Whether we’re fleet managers or private vehicle owners, we’ve all dreaded driving into the petrol station at some point. Or even on multiple occasions because we know that a cent will leave our pockets for every drop filling our tanks. High fuel consumption in petrol engines is caused by many factors, such as:
Driver behaviour: Have you ever thought, “I am an excellent driver”, as you skidded and almost bumped the sidewalk while going around a sharp corner? Or, have you ever thought that this must be going through one of your drivers’ minds when you see them coming around that corner? We hope not! Managing your drivers’ bad driving habits can be challenging, especially if you don’t know their bad habits, so being able to monitor their driving can help you increase workplace safety and compliance.
Vehicle maintenance: Imagine driving with your windows down, music blasting, and the wind blowing through your hair, and suddenly, all your warning lights go on, and your car sputters to a pathetic halt. Did you forget to service your vehicle? Staying on top of your vehicle maintenance and regular servicing can feel like admin, but it is crucial for avoiding downtime, optimising your vehicle’s fuel efficiency, and ensuring uninterrupted off-key singing as you face the daily traffic.
Vehicle load management: Most of us have seen a truck on the highway that’s so overloaded that it looks like it will topple over as soon as it hits the next pothole. Whether you’re a fleet driver or manager or you’re helping your cousin move to a new town, it’s crucial to understand the risks of overloading and how this can affect your fleet or vehicle’s fuel efficiency. Stick to the vehicle’s limits to allow your engine and fuel budget to thrive.
Traffic conditions: Sitting in traffic sometimes looks like this: Singing a song (off-key again), wondering whether the traffic would have been better if you left just ten minutes earlier. Staring into space—or at fellow motorists—and wishing you could just switch to the lane you’re supposed to be in but are unable to do so because traffic is packed like a buffet lunch plate on a Sunday afternoon. Worst of all, your petrol engine is idling, wasting precious fuel.
Whether you’re driving your private vehicle or managing a fleet, the factors contributing to fuel efficiency remain relatively the same. So, would it make a difference if these vehicles ran on diesel? Let’s compare the two.
The engine showdown: petrol vs diesel
First-time vehicle buyers often don’t think about whether they want a petrol engine or a diesel engine vehicle. Let’s be honest: our first five questions are something along the lines of: what does it look like, what brand is it, what colour is it, what’s the mileage, where is it, and does it have Bluetooth capabilities so that I can play music? Let’s look at some of the major differences between petrol and diesel engines:
Category
Petrol engine
Diesel engine
Fuel efficiency
Less fuel efficient, however, they are generally more responsive and better suited for smaller vehicles.
More fuel efficient because of their higher compression ratio which results in better mileage.
Power and Torque
Has higher horsepower, making them better suited for speeding.
Produces higher torque, which is great for towing.
Maintenance costs
Usually cheaper.
Generally more expensive because of complex components.
Emissions
It produces fewer nitrogen oxides but more carbon dioxide, negatively affecting greenhouse gas emissions.
Emits more nitrogen oxides, resulting in higher air pollution. However, DPFs have improved this.
Engine longevity
Tend to have shorter lifespans, but the evolution of technology is slowly closing the gap between petrol and diesel engines in this category.
Have longer lifespans, and that’s why they are more often used in commercial vehicles.
Noise and vibration
They are quieter and offer a better driving experience because of their smoothness.
Tend to have noisier engines with more vibrations; however more modern diesel engines have reduced these effects a lot.
Fuel costs
Tend to be less expensive however the price between diesel and petrol doesn’t generally differ significantly.
More expensive in general; however, the price can fluctuate.
Commercial and personal vehicles have different purposes; even industry-specific commercial vehicles’ purposes can differ vastly. There are benefits to both petrol and diesel engines that make them suitable for specific purposes, making both of them relevant and valid options.
Petrol engines: the fuel-mongers
There are various reasons why petrol engines use a lot of fuel. Let’s look at some of them:
Lower thermal efficiency: In general, petrol engines have lower thermal efficiency than diesel engines. What does this mean? Engine thermal efficiency is the percentage of the fuel’s energy used to power the engine rather than using it for other components such as the exhaust or coolant. A higher thermal efficiency means that the engine uses fuel more effectively.
Stoichiometric ratio: A stoichiometric ratio refers to the ideal balance of air and fuel in an engine, which allows an engine to use fuel efficiently without leaving any unburned fuel or extra air behind. Petrol engines can be pretty finicky, and because of their finicky nature, they require precise air-fuel ratios (approximately 14.7:1) for the most desirable combustion conditions. To ensure that combustion is complete, petrol engines tend to use more fuel, specifically when the vehicle is overloaded or accelerates regularly.
Three-for-one: Driving conditions, driver behaviour and petrol engines: Driving conditions, bad driving habits, and a petrol engine equals high fuel consumption every time. Poor driving conditions include stop-and-go traffic, which consumes more petrol because of frequent idling and acceleration. Bad driving behaviour includes aggressive acceleration and braking, resulting in higher fuel usage.
Energy density of fuel: Petrol engines tend to have a lower compression ratio than diesel engines, which makes them less fuel efficient and use more fuel.
Higher RPM operation: Petrol engines operate at higher revolutions per minute (RPM) than diesel engines do. Higher RPMs lead to higher fuel consumption because more fuel is injected into the vehicle’s engine to maintain the speed and power at which the vehicle is operating.
How does high fuel consumption affect the value of your vehicle?
Lowered resale value: Potential buyers might think twice before buying a petrol-engine vehicle because it is less fuel-efficient. This decrease in demand can negatively affect your resale value. Another contributor to your vehicle’s lowered resale value is the fact that the vehicle will be more expensive to operate.
Speedy depreciation: Your vehicle’s value can decline faster because of its poor fuel efficiency.
Environmental impact: With the rise of ecological consciousness, many buyers might consider buying a more fuel-efficient option because vehicles with higher fuel consumption are less environmentally friendly.
How do fuel costs influence your operational dynamics?
Fuel consumption is one of the biggest expenses of any fleet business. Here are four ways that it can impact different parts of your business:
Rising operational costs
Increased fuel prices: Fuel prices regularly yo-yo in South Africa because of factors such as global oil prices and fluctuating currency exchange rates. A rise in fuel prices directly impacts businesses’ operational costs, especially if they rely on vehicles for services such as making deliveries.
Managing your budget: Operational budgets must constantly be adjusted because of fuel expenses, which impacts the availability of funds for other operational needs such as maintenance and staffing.
Profit margin implications
Profit decline: Organisations with slim margins can have a smaller profit margin caused by their fleet’s high fuel consumption. The more fuel the fleet needs, the bigger the impact on the business's profits, especially for businesses that operate in transportation or delivery services.
Adjusting prices of services and products: To maintain profitability, businesses might have to change the prices of their products and services, which might negatively affect their standing as competitors and their customers’ satisfaction.
Supply chain efficiency
A rise in logistics costs: Your supply chain efficiency might be influenced by higher product costs caused by high fuel consumption, primarily if your fleet operates in the manufacturing, retail or distribution industries.
A need for route optimisation: Organisations might consider investing in route optimisation tools. Although it might be an additional expense every month, it will reduce fuel costs wasted on unoptimised travelling routes.
Fleet management challenges
Maintaining your fleet vehicles: Wear and tear on your vehicle is often a result of higher fuel consumption because it increases the strain on your engine. When a vehicle uses more fuel, it works harder due to aggressive driving, cargo overload, or inefficient operations.
A lack of fuel-efficient vehicles: Organisations might have to consider investing in more fuel-efficient cars to combat high fuel consumption and costs.
How Cartrack can help you skyrocket your petrol engine’s fuel efficiency
Managing your fleet while trying to lower your fleet’s fuel consumption, or even just managing it better, can be pretty tricky. At Cartrack, we offer multiple solutions to every fleet management problem you might have, some of which include:
At Cartrack, we can help you optimise fleet drivers' routes.
We can help you track your drivers’ behaviour and identify any harsh driving habits they might have, all while giving you coaching tools to improve those behaviours.
You can get a range of different reports to monitor your fleet's fuel consumption, driver behaviour, and CO2 emissions, among other things.
Avoid aggressive driving, such as harsh acceleration and harsh braking. You should instead maintain a steady speed.
Don’t idle your vehicle for long periods. Instead, turn your vehicle off, and in the colder weather conditions, don’t idle your vehicle for more than 30 seconds to 1 minute.
Plan your and your fleet drivers’ routes to avoid traffic and other congestion issues, such as accidents.
Don’t miss a vehicle service. You might want to skip this one, but you shouldn’t. The more you extend your fleet maintenance, the more problems your fleet might experience later.
Be mindful of how much cargo you load on your fleet vehicles, and make sure that your load is evenly distributed to prevent unnecessary strain on just one side of your vehicle.
Don’t overuse your air conditioning. In the hotter months, when temperatures reach the dreaded 30°Cs, the first thing we want to do when we get in our vehicles is turn on the air conditioning on full blast but we should try to refrain from doing that. You should park your car under the shade or leave your window open just a bit to get ventilation.
Use high-quality fuel only. Support your mainstream fueling stations where you know the fuel quality is up to standard. Dirty fuel can cause different problems in your vehicles, such as engine breakdowns.
Make the most of the telematics technology that’s available to you. Improve your fleet’s fuel consumption by leveraging the telematics technology that’s available to you. In this next section, we will look a bit more into this.
How telematics can help you manage fuel consumption
Telematics can help manage and improve your fuel consumption; here’s how:
Monitoring live driver behaviour: You can keep track of your entire fleet and drivers’ behaviour, such as harsh acceleration and speeding. With the accurate data the telematics device receives, you can improve driver behaviour through coaching.
Optimising routes: You can optimise the routes that your drivers take in real time, which allows you to save on fuel costs.
Vehicle maintenance alerts: Regular maintenance can save you money on vehicle breakdowns. You can set up maintenance alerts for each vehicle or your entire fleet.
Tracking your fleet’s fuel usage: Telematics can give you a detailed overview of your fleet’s fuel usage patterns. By analysing these patterns, you can identify where your fleet tends to waste fuel or use excessive fuel the most, you can then address these areas.
Reducing vehicle idle duration: When your drivers idle for long periods, they are wasting fuel without being productive. Telematics systems can monitor the duration and how often your fleet drivers idle your vehicles.
Integrating systems with your current fleet management systems: Combining telematics systems with your current fleet management systems allows you to operate more cohesively. By combining data from different sources, you can make better-informed decisions about how to reduce fuel consumption.
Don’t let fuel costs rule you: rule it with Cartrack
Contact Cartrack today and discover a new way to lower fuel consumption in your petrol engine.
Frequently Asked Questions about High Fuel Consumption
How do you fix high fuel consumption? There are several ways that you can “fix” your fleet’s high fuel consumption, here are a few:
Don’t speed
Take your vehicle for regular maintenance checks
Make use of fuel additives
Keep an eye on your RPMs
If you’re driving a modern vehicle - utilise the cruise control function
Why is my petrol car using so much fuel? There isn’t just one answer to this question, as there are several factors that might cause your vehicle to use a lot of fuel; some of these factors are:
Aggressive driving behaviour - harsh acceleration and braking
Excessive idling
Regularly being stuck in traffic or stop-and-go
Not having the correct oil and filters
Your clutch might be worn
What are the possible causes of high fuel consumption? High fuel consumption can have different origins, such as:
Aggressive driving
Driving in the wrong gear
Idling too often and for too long
Not changing your oil regularly
Using your air conditioning too often
Can injectors cause high fuel consumption? Yes, injectors can cause high fuel consumption. If your injectors are dirty or worn out, they can burn fuel at a faster pace, which increases fuel consumption.
Find out what causes high fuel consumption in petrol engines and how to improve your vehicle’s fuel consumption with Cartrack.
