The Impact of Short Commutes on Diesel Cars: How Short Trips Affect Engine Health and Fuel Efficiency

Driving a diesel car for short distances can have significant impacts on its performance, longevity, and overall efficiency. While diesel engines are designed to perform optimally at higher temperatures, short trips might not allow the engine to reach and maintain these optimal conditions. This article explores the negative effects of short trips on diesel cars and offers suggestions to mitigate these issues.

Why Short Trips Are Bad for Diesel Cars

Incomplete Combustion: Diesel engines operate most efficiently at high temperatures, but short trips might prevent the engine from reaching these optimal conditions. Incomplete combustion can result in increased emissions and the accumulation of soot and carbon deposits in the engine and exhaust system. These deposits can clog vital parts of the engine, leading to degraded performance and potential damage.

DPF Issues and Short Trips

Diesel Particulate Filter (DPF) Management: Many modern diesel vehicles are equipped with a DPF, which captures and stores soot from the exhaust. However, short trips may not allow the DPF to reach the necessary temperature for regeneration, potentially leading to blockage and reduced engine performance. This can result in decreased fuel economy and even engine inefficiencies.

Impact on Fuel Economy

Fuel Efficiency: Diesel engines are generally more fuel-efficient on longer trips. Frequent short trips can lead to lower overall fuel economy compared to longer drives, where the engine can operate more efficiently. This is especially true in stop-and-go traffic, where the engine operates under constant start-and-stop cycles that can reduce fuel efficiency.

Short Trips and Battery Drain

Battery Drain: Short trips might not provide enough time for the battery to recharge fully, especially if the vehicle has numerous electrical accessories in use. This can lead to battery drain over time and decreased performance. Repeatedly draining and recharging the battery can also affect the battery's longevity and overall health.

Mitigating the Effects of Short Trips

To overcome the negative effects of short trips, it is advisable to take longer drives periodically to allow the engine to reach its optimal temperature and to clear the DPF. If short trips are unavoidable, consider occasional longer drives to help maintain the vehicle's health. This can help prevent the accumulation of soot and carbon deposits, preserve engine efficiency, and maintain overall vehicle performance.

Real-World Observation: A Long Trip with a Diesel Ute

A real-world observation during a long trip using a diesel ute hauling a heavy generator highlights the significant impact of short stops on fuel efficiency. While cruising, the vehicle was consuming approximately 11 liters of fuel per 100 kilometers. However, if the vehicle stopped for a few minutes, the fuel consumption sky-rocketed to three times the amount, and it took about 15 minutes for the vehicle to return to its normal fuel consumption after starting again. This is likely due to several factors, including:

Cold metal surfaces Incomplete combustion Soot in the exhaust Chemical contamination of the oil

These conditions are generally not favorable for the engine or the environment, as they result in higher emissions and decreased fuel efficiency.

Engine Health and Vehicle Selection for Short Trips

Engine Strength: Diesel engines are inherently stronger due to the high compression pressures, which require more metal content than petrol engines. As a result, they need more time to reach thermal equilibrium. For short trips, lightweight air-cooled petrol engines might be superior to diesel engines. For the most efficient and eco-friendly option, consider an electric vehicle (EV) designed for short trips and frequent small charging. Instead of a large heavy car with a massive battery pack to offer a range of 700 km, opt for a vehicle specifically designed to meet the needs of short commutes.