General Car Maintenance

Improving Your Fuel Economy – General Car Maintenance

The old saying goes that nothing runs better than a well-oiled machine and your car is no exception. If everything is well maintained and running as it should be you will experience the best fuel economy, reliability, and performance that your vehicle can provide. If you fail to maintain your vehicle, however, you will start to see an expensive decrease in one or all aspects.

Tires and Brakes

Many people neglect their tires and brakes, which don’t really make any sense when you think about how important they really are; tires are the only things which actually maintain contact with the road and brakes are what slow you down. If anything, it would make the most sense from a “Let’s Keep Living” standpoint, to pay the most attention to these parts.

Avoid any incidents by having tires on your vehicle that are the proper size and in good standing; change the brake pads and have the rotors machined as soon as you begin to hear the signature break squeal.

Proper maintenance of your tires and brakes could give you up to 10% better fuel economy.

Air Intake and Exhaust System

The second most neglected part on your car besides your tires is your air filter. An air filter cleans the air that is introduced into the engine, ensuring that no particulates get into the combustion chambers. Having a clean and efficient intake system means more horsepower and more fuel economy. Change your air filter every 15,000 miles if you live in the city or whenever you see it get physically dirty.

Your exhaust removes waste gasses from the engine. Removing these gasses faster increases both horsepower and fuel economy. Ensure that all the components of your exhaust, the manifold, resonator, catalytic converter, and muffler, are in good condition and are not obstructed. Slowing down your exhaust flow will decrease both power and fuel economy.

Maintaining your intake and exhaust system can gain you up to 10% better fuel economy.

Oil

Changing your oil regularly means that the oil is less restrictive, lubricating the moving parts within your engine without causing any friction and the resulting power losses. Having oil and gunky oil in your engine can cost you 1% or more of your fuel economy.

Driving Behind Semi’s and Big Trucks

Improving Your Fuel Economy – Driving Behind Semi’s and Big Trucks

Drivers tend to adopt an entirely different persona when they are on the highway. What is normally a defensive and considerate driver becomes an impatient, aggressive speed freak who routinely does 10 to 20 miles per hour over the speed limit. Highway driving, to say the least, is both unsafe and taxing on your fuel economy.

Most speed limits of American highways are set at around 60 miles per hour, though there are some freeways and highway systems that have speed limits that are slightly less restrictive. What you probably aren’t aware of is how high speed driving, even when cruising, affects your fuel economy.

High Speed Driving and Fuel Economy – How They’re Linked

Have you ever been water skiing? If so, do you know the sensation of falling? Once you let go of the rope and fall you stop in a matter of seconds, regardless of how fast you were traveling before hand. The water places sufficient resistance that you will come to a complete stop whether you like it or not.

Driving is the same way.

The faster you are driving the more air resistance your vehicle is enduring. When you let off the gas, the engine stops creating thrust and your vehicle begins to slow down. This is more apparent at higher speeds as opposed to slower speeds, and this is the direct result of air resistance (also called wind resistance). Ever noticed how your car slows down faster when you are going faster? That is because the car is facing more resistive forces.

Obviously, the more resistance that is placed on the car the more fuel that will be required to continue operation at a given speed.

Driving Behind Semi’s – How It Affects Fuel Economy

As we mentioned prior, air resistance has a significant impact on fuel economy- this is why you see hyper-aerodynamic vehicles, such as the Honda Insight or Toyota Prius in production. Now, when a larger vehicle (such as a big truck or a Semi) is driving it has to pierce through a lot of air. In the space behind it there will be substantially less air resistance, as the Semi has already plowed through the air .

This phenomenon is called “drafting,” you may have heard this term if you watch automotive racing. Following a Semi at a safe distance is a way to increase your fuel economy as a result of the reduced resistance on your own vehicle. It’s like following in the wake of a large boat; the boat has already chopped through the water, leaving behind it a patch of smooth water.

Controlling Your Acceleration

Improving Your Fuel Economy – Controlling Your Acceleration

The light turns green and you have the pedal to the metal. In a frenzy of tire squealing and an impressive surge of torque the car leaps forward, forcing your head back into the headrest. The speedometer screams skyward, and in a Newton-like reaction, the gas gage plummets toward the earth. Your impressive jaunt to the speed limit has wreaked havoc on your fuel economy.

The reality is that 99% of us don’t drive sports cars or even cars that are remotely sporty in nature. The majority of vehicles sold are trucks, family sedans, and compact economy cars. None of these popular vehicles are sporty in nature, yet many drivers feel the need to burn as much hydrocarbon as possible when they are accelerating. Perhaps it is the anemic performance of these vehicles which triggers this type of response, or maybe it is the strong desire to become a race car driver, regardless of the reasoning behind it, nailing your throttle full-on is the number one fastest way to kill your fuel economy.

The Mechanics behind Fuel Consumption and Throttle Response

If you give the throttle everything you’ve got the engine prepares itself to be sent into overdrive. The computer sends more air and fuel into the cylinders, which in turn creates a larger, more volatile explosion where the result is forward thrust, and lots of it.

Gently press the throttle, however, and the computer will send in conservative amounts of air and fuel, resulting in a smaller explosion and a lower amount of thrust. However, as your vehicle gains momentum, you will still reach whatever speed you are trying to hit. It will just take you a bit longer to do so.

It is important to note that your engine becomes thirstier when it is operating higher in the RPM range- the engine is further into its power band and as soon as you touch the throttle it is ready to provide a large surge in power.

The Skinny on Trimming Your Fuel Consumption

The reality is that the more you control your throttle the better your fuel economy will be. Have you ever heard the saying that your mood will have the biggest impact on your economy? It’s because when people are angry they tend to drive more aggressively, accelerating harder and stopping faster.

Want to go further on a take of gas? Control your acceleration. There is no single way that is more effective at improving fuel economy and to make that $3.00/gallon get you a little father.

Maintaining the Speed Limit

Improving Your Fuel Economy – Maintaining the Speed Limit

Driving the speed limit will save you money. Besides not receiving speeding tickets and higher insurance premiums, driving the speed limit generally keeps your vehicle in an RPM range that is ideal for maximum performance and fuel economy.

Studies have shown that speeds in excess of 55 miles per hour (90 kilometers per hour) decrease fuel economy at an exponential rate. The difference between driving 55 miles per hour and 65 miles per hour may only be four or five minutes of travel time but it may cost you an extra $5 in gas. Consider that driving the speed limit is like being paid $5-$10 per to take that trip.

The Mechanics Behind Slower Speeds and Fuel Economy

There are many different variables which affect fuel economy: engine efficiency, operating temperature, the drag coefficient of the vehicle (dictated by the aerodynamics of the vehicle’s design), the type of fuel being used and the elevation of the driving environment. Phew – that’s a lot to consider.

Driving at slower speeds directly affects the drag coefficient of the vehicle. Though the actual coefficient value doesn’t change, the resistance placed on the vehicle by the ambient air or wind does change based on speed. The faster you are moving, the more resistance that the air will place on the vehicle.

Imagine that the ambient outside air, the environment in which your vehicle must drive through, is a gigantic bowl of water; the moment that you remove your foot from the gas your vehicle immediately begins to slow down. Have you ever noticed that coasting at slower speeds lasts longer than coasting at higher speeds? This is because when you are driving at high speeds your vehicle must slice through the air.

Variables, such as wind resistance and even temperature/air density will affect your vehicles ability to do this efficiently. When cruising at 20 miles per hour, less resistance is placed upon your vehicle. This is due to the fact that the air has more time to channel around the vehicle, as opposed to colliding with it. When cruising at 80 miles per hour, the air has substantially less time to channel around your vehicle meaning that the result is a 100% difference in fuel economy from 40 miles per hour when compared with 80 miles per hour.

In Closing

The need to get wherever you’re going quickly can overcome your desire to get optimum efficiency from your vehicle. However, the faster you drive the more fuel you will burn. Next time you go for a long drive on the highway, try cruising at the speed limit as opposed to 5 miles per hour over. You will notice a definite difference in fuel consumption.