Short Distance Driving - only harmful for the Diesel Engine?

Facts & Comparison with Gasoline Engines

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Diesel engines are often more susceptible to wear and tear and damage to important components than petrol engines, especially on short journeys. But what is the difference between these two engine types? Why are diesel engines less suitable for short journeys than petrol engines and what damage can be caused by driving short distances? You can find out about this and other technical aspects in this article.

1) How long are short distances?

In principle, there is no fixed number of kilometers that is considered a short distance. For physical reasons, the minimum limit according to experts is ten kilometers. In this short period of time, the motor does not manage to Operating temperature to come.

As a result, of course, the Lubricity of the engine components. Every vehicle and of course every motorization has a individual temperature profile. To find out your individual minimum limit, simply drive until your car is at operating temperature. You can then calculate the distance covered as Set your individual minimum limit.

Up to 10km = short distance and 25km ideal distance
10 kilometers = "minimum", 25 kilometers = "ideal distance" (generally speaking)

2) Difference between diesel engine and gasoline engine

The main difference between diesel and petrol engines lies in the way they work. While the air-fuel mixture in the combustion chamber of a petrol engine is ignited a spark diesel engines work differently.

In diesel engines, the mixture is regulated by High pressure conditions in the combustion chamber ignite. Therefore called Diesel engines also compression ignition and gasoline engines spark ignition. The big advantage of the diesel is basically that it has a higher efficiency than the gasoline engine. As a result, the diesel also consumes a little Less fuel.

Description Function diesel engine and gasoline engine
Different injection systems for diesel and gasoline engines

3) So short journeys only damage the diesel vehicle?

No. Short journeys damage diesel vehicles as well as gasoline vehicles. The reasons for this are:

→ Limited lubricity of the engine oil:

The full Lubricity of the engine oil is only reached when it has an operating temperature of approx. 90 - 100°C. For a short distance under 10 kilometers the oil will never reach this temperature and therefore lose lubricity. Furthermore, some fuel always gets into the oil pan during the combustion process. This fuel cannot evaporate at low temperatures and thus dilutes engine oil. This naturally affects the lubrication of the mechanical components and the Wear and tear is increased.

Engine oil filling loses lubricity after many short journeys
The lubricity of the engine oil suffers under short journeys

→ Restricted mechanism: from engine and exhaust components

This restriction is related to thermodynamic principles together. The engine of a vehicle consists of various components such as cylinders, pistons, valves and seals, all of which work in precise interaction.

For short journeys, the car is not sufficiently brought up to operating temperatureso that not all components can function properly. The thermodynamic processes required for a Efficient combustion and performance development are not fully realized.

The ignition of the fuel-air mixture, combustion and the transfer of energy into mechanical work are influenced by the restricted operating temperature. This can lead to incomplete combustion, lower efficiency, increased wear and Damage to the mechanical components lead.

The complex mechanism of the engine components
Cold temperatures reduce the efficiency of mechanical components

→ Water in the exhaust - rust

The connection between water in the exhaust and short journeys lies in the fact that the Exhaust pipes do not get hot enough (especially in winter). This prevents the water in the exhaust system from evaporating. You can find out more in the article: Water from the exhaust - harmful?

Rusted rear silencer caused by short distances
Condensation causes the exhaust to rust

→ Coking

Short trips favor the formation of Deposits and coking in the engine components. This is because the exhaust tract does not run hot long enough to burn off and remove these deposits. Coking can lead to a loss of power, increased fuel consumption and even malfunctions. This affects both diesel and gasoline engines. In diesel vehicles, the Function of the EGR valve thus severely limited.

Soot in the intake manifold and in the EGR valve due to short trips
Coked intake manifold and sooted EGR valve

→ Catalytic converter and particulate filter

In addition, exhaust components such as the catalytic converter and particulate filter can also be affected. A catalytic converter works on most efficient at certain operating temperatures. If these temperatures are not reached, the catalytic effect can be reduced. Similarly, the particulate filter cannot perform its cleaning function properly if it does not reach the temperature required to clean the particulate matter. to burn soot particles.

Cold KAT+DPF
Catalytic converter & diesel particulate filter (DPF) on the BMW F30

4) Why is the diesel still more susceptible to short trips?

This is because diesel engines, due to their design and mode of operation, have a require a higher operating temperature than gasoline engines. For short journeys, however, diesel not enough timeto reach this operating temperature. This means that the Oil not fully heated which leads to it mixing with fuel and other particles and causing the Intake tract dirty.

The Exhaust gas purification systems can be restricted in their function, which can lead to wear in the long term. Gasoline engines, on the other hand, reach operating temperature more quickly and therefore have a lower minimum limit for short trips.

INFO BOX:

When is an engine actually "warm"?
An engine is not immediately considered "warm" when the water temperature has reached approx. 90°C.

The water temperature is the display that you see on your speedometer or on the on-board computer. The oil temperature is usually hidden in a submenu and is the actual indicator for a warm car. The oil temperature is usually only at operating temperature (80°C - 100°C) after a further 10-15 minutes. Only at this point is the car completely warmed up.

5) Is the gasoline engine better for short trips?

Compared to diesel engines Petrol engine better suited for short distances. You do not need such High operating temperature as the diesel in order to work effectively. As a result, gasoline engines are generally less susceptible to damage caused by the Driving short distances can be caused. The Cleaning the flue gas system is also better than that of the diesel, which Pollutant emissions reduced.

Short distances are better suited to gasoline engines
A gasoline-powered vehicle is the better choice for short trips

6) Which components are damaged by short distances?

Short journeys can lead to Large number of damages on various engine technology components. These include, for example Deposits in the engine oilwhich can contaminate the engine and lead to a reduced service life. The exhaust gas purification systems can also be damaged and their function restricted. This includes the aforementioned EGR valve and the catalytic converter or particulate filter.

One Coking of these components or the intake manifold can lead to increased pollutant emissions and the vehicle losing additional power. Furthermore, various mechanical motor components loadedas they have to provide the required work when cold and immobile.

7) What can you do about unavoidable short trips?

As you have probably already guessed, the answer here is: Long-distance trips!

However, there are other small measuresthat will help you to take less damage from short journeys. A widely used method is to leave the car bring to operating temperature before driving off. To do this, you should let the car idle for a few minutes until the combustion engine is warm. However, this method is Highly controversial. On the one hand, it is a nice way of preheating the engine and even makes the interior a little warmer in winter, but all at the expense of fuel, the environment and soot. At idle, the EGR valve is at its widest open, allowing exhaust gas into the intake tract. You should decide for yourself whether this compromise is an option for you.

Another tip is to make your Shorten service intervals. If you often drive short distances, you should make sure to change the oil and filters regularly. This helps to keep out dirt particles and soot, which are increasingly present in the engine due to short journeys, and to keep the engine running smoothly. Minimize wear and tear. If you follow these tips and have your car serviced regularly, you can significantly extend the service life of your vehicle. Ideally, of course, you should take your car out for a long drive between short trips.

INFO BOX:

You also shouldn't let it scare you too much. If you drive short distances three to four times a week and then long distances twice a week, this will have minimal to no effect on your vehicle. We're mainly talking here about continuous short trips that damage your vehicle.

A good balance between long and short trips will also keep your engine healthy. In summary, you should make sure that you do as little short-distance driving as possible. However, that doesn't mean you have to skip them altogether.

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