I was wondering should diesel motors be left idling as I drive by a truck stop or travel plaza in the wintertime. I see lots of smoke pouring out of the exhaust pipes of semi-trucks standing still. Why is that happening? Don't those truckers know they're polluting the air and wasting fuel?
The answers to the questions are both yes and no. Diesel motors idling at the truck stop are not a conspiracy to ruin the environment and waste a precious natural resource. You've got to look a little further than what you can actually see to understand the reason for this questionable behavior. The decision to run the diesel motor while the rig isn't moving is a strategic consideration and not done on a whim or without awareness. Remember, diesel fuel costs a lot of money, and wasting fuel going nowhere isn't going to go unnoticed by dispatchers and fleet managers. Idling diesel motors keep the truck and trucker going, even when the truck itself isn't rolling down the road.
A Universe Unto Itself
Most folks fail to understand the situation truckers face as they make their way across the highways. A tractor-trailer rig is a world unto itself. Not only does it have to move cargo from Point A to Point B, it has to do it efficiently and safely with a close eye on economy. Think of it like it is a rocket ship that travels from planet to planet. The ship has to contain the cargo, fuel for the engines, and a control system that keeps it from getting lost across the vast expanses of space. This rocket ship has to avoid comets and asteroids, load and unload its cargo safely, and do it all over again time after time.
A Short Primer on Diesel Motors
For those who don't know about the inner workings of a diesel motor, there are a few details that will help you understand what's going on mechanically. The main discussion points are:
Stronger by design - Diesel motors produce more power or torque than gasoline motors and they do it at a lower RPM speed. Everything about a diesel motor's engineering and construction is focused on durability and strength.
Exhaust differences - Both diesel and gasoline motors put out carbon and other contaminants into the air, with diesel engines producing about the same amount of Carbon Dioxide (CO2). New Diesel Exhaust Fluid filter technology has significantly reduced the amount of noxious Nitrogen Oxide (NO) introduced into the environment.
Diesel fuel versus Gasoline - The density of diesel fuel is different from gasoline and it takes a greater amount of compression to get diesel fuel to fire. Gasoline is a lighter, thinner compound that ignites at a lower temperature. This allows diesel motors to create more torque at a lower RPM than gasoline motors.
Old tech + New tech - The Diesel motor was invented by Otto Diesel in 1897. Since then, many improvements have increased operating efficiencies while reducing maintenance costs and extending engine life. Diesel motors outlast gasoline motors in terms of engine life and durability.
Idling Motors Aren't Idle
It's a funny thing but most folks seem to think a truck sitting still isn't working, but nothing could be further from the truth. Just because a vehicle isn't moving doesn't mean it isn't getting a job done. Truck drivers, like everyone else, have to have food, sleep, and other necessary accommodations to accomplish their job. Like the rocket ship analogy, the driver is like an astronaut flying his space ship through the galaxy. Everything he needs has to be on board the rocket ship or else the driver will die and his cargo will be lost in space. Like a rocket ship, what you see on the outside is a lot less than what's going on inside.
The Heartbeat Keeps Going
A semi-truck sitting still has to keep working in many situations. The work may not involve rolling down the road, but it is work nonetheless. Work like keeping the rig warm inside during cold winter nights or recharging the batteries. Because it is a self-contained world, a truck has to feed, clothe, shelter, and provide living space for its driver. This is accomplished with equipment like heaters, air conditioners, refrigerators, televisions, computers, and a dozen other critical systems. Even when still, a truck and its driver still have work to do and when they don't, A driver has to be able to eat, sleep, and function on the road without support of any kind in many situations. His truck's diesel motor makes it all possible. More than just a transport vehicle, a semi-truck is also an office and a home at the same time.
Getting Better and Better
Enhancements and improvements in fuel system efficiency combined with advances in oils, engineering, and pollution control have resulted in much less toxic emissions being placed into the air. Diesel fuel itself has been re-engineered to produce lower emissions while enhancing power production. This allows diesel motors to run more efficiently at low RPM, saves on fuel consumption, and reduces the amount of contaminants introduced into the air. Future improvements target filtration processes that will scrub all contaminants from the exhaust other than carbon dioxide. Emissions restrictions and environmental concerns have driven the research and development of a variety of diesel motors with enhanced performance capabilities that don't sacrifice power or productivity.
Keep On Truckin'
Every type of transportation requires some kind of engine to make it move. Electricity, gasoline, hydrogen, helium, solar, and a dozen other technologies are all competing for the same space when it comes to moving cargo. While the technology powering the industry may change, the industry itself won't. Getting products to people is what trucking is all about and one of the most important components in that process is the kind of power required to get it done. Diesel motors may not be the ideal solution but they are an excellent solution that can handle the responsibility. Truck drivers breathe the same air as everyone else and they, too, are concerned about pollution. Achieving a responsible and fair balance between transporting goods and impacting the environment in the process is the challenge.