Engine idling: what it is, causes and reducing it in fleets

“Idleness” is the term used to describe something inactive. In the case of engine idling, it means keeping the vehicle running without moving.

Although the engine also suffers in this situation, what is considered a major problem is the increase in fuel consumption and pollutant gas emissions. It is no secret that refueling costs are a constant target for managers, who are always seeking to reduce spending in this area.

However, few look at the problem of engine idling as an alternative way to achieve this goal. Today, we will cover:

• What engine idling is;
• When engine idling happens;
• What consequences engine idling causes;
• How to reduce engine idling periods.

What is engine idling?

It is when the engine is running and the vehicle is stationary. For example, stopping for a delivery and leaving the vehicle running while unloading its dump body.

It is worth emphasizing that “engine idling” is different from “fleet idleness.” Fleet idleness occurs when vehicles are broken down or stopped for repairs in the operation's garage and repair shop.

This affects the company's operational efficiency through poor use of space and fleet vehicles.

When does engine idling happen?

There are different situations in which an engine can be considered idle. Some of the most common are:

• The driver starts the vehicle to turn on the air conditioning and keeps it stationary before leaving;
• Time stopped in traffic, especially during road construction and accidents, potentially remaining in the same place for hours;
• Loading and unloading the vehicle at docks, depots or warehouses;
• When one driver gets out to buy food and the other waits with the vehicle running.

Operational idle time vs. actual idle time

It is important to distinguish that engine idling does not apply to every moment when the vehicle is running and stationary. In some cases, stopping is part of the operation, but this does not mean the engine needs to keep running throughout the entire period.

One case involves preparing the vehicle before departure. Instead of keeping the truck stationary for many minutes to warm up, it is worth following the manufacturer's and maintenance team's technical guidance: the engine tends to warm up faster in motion than while stationary, and fuel economy is worse while the engine is still cold. That is why waiting time with the engine running should be treated as an exception and controlled by the operation.

What consequences does engine idling cause?

Premature engine aging

In brief, the engine's job is to burn fuel, providing the power needed for the vehicle to work properly. If the vehicle is running and the engine is not completing its work, it begins to suffer some consequences.

Among them, fuel does not burn properly, accumulating on engine components and causing loss of lubricating oil. In the long term, this causes friction between parts and accelerates engine aging.

Improper fuel combustion

For the vehicle to start and stay in motion, the engine needs to burn fuel. If the vehicle is started and does not move for an extended period, this combustion becomes irregular.

In addition, leaving the engine idling consumes fuel even without movement. According to a FuelEconomy.gov estimate, idling can use a quarter to half a gallon of fuel per hour, a variation that depends on the vehicle and accessory use.

Increased fuel consumption

Improper fuel combustion is one factor that increases refueling costs. In addition, if the vehicle is running and stationary, fuel waste is evident because it is not being used in the most efficient way to carry out transport.

This care also applies to air conditioning before a trip: FuelEconomy.gov recommends not leaving the vehicle idling with the air conditioning on before driving. In many situations, restarting the vehicle after a short stop uses less than keeping the engine running unnecessarily; the same source indicates that starting uses fuel equivalent to about 10 seconds of idling.

High maintenance costs

With premature engine aging and excessive loss of engine lubricating oil, maintenance costs also increase. After all, more services are needed, more frequently.

In fact, very frequent engine repairs may be one sign that engine idling is a problem in your fleet. That is why it is important to have well-established maintenance management.

Greater pollutant gas emissions

Heavy vehicles are among the relevant sources of pollutant emissions in transport, especially when they cover long distances, use fuel intensively and spend long periods running without moving.

When a vehicle remains with its engine idling, it can further increase environmental impacts because there is consumption and emissions without the fleet advancing its operation. That is why reducing stationary time with the engine running helps cut waste and contributes to a more efficient operation.

How can you reduce engine idling periods in your fleet?

To prevent engine idling from becoming a frequent problem in your transport operations, you need to keep track of situations when the vehicle is stationary and running, review stopping routines, guide drivers and keep maintenance records up to date.

Fleet monitoring

Monitoring will be essential to understand idle periods and what caused them: traffic, stopping to unload the truck, waiting at a dock, an operational break or even no clear reason, which should be checked with the driver on the route.

Take care when choosing a process or system that produces the information you need for this case, without treating every stop as a problem. The point is to separate what is inevitable, such as an operational wait, from what can be reduced through guidance, route planning, working hours management and clear agreements with the team.

Driver training

In the second alternative, part of your fleet role is to provide training that contributes to positive transport operation results.

Classes, talks and simulator practice on defensive and safe driving are fundamental and provide the ideal moment to show what engine idling is, when stopping with the engine running is acceptable and when it becomes wasteful. It is also worth reiterating that prolonged stationary warm-up should not be treated as a general rule, since the engine warms up faster in motion.

Driver control and trip control using spreadsheets or systems contribute to and greatly facilitate identifying who is causing more problems with engine idling.

Maintenance control

Through control of preventive and corrective services, you can assess engine operation and instances of engine idling. That is why having a system or spreadsheet to record completed and planned services is a very interesting alternative.

Learn how to create your maintenance control spreadsheet in our post on the subject.