방문운전연수
With gas prices at all-time highs, fuel efficiency is top of mind for many drivers. A lot of things factor into your vehicle’s fuel efficiency. Routing, driving behavior (like rapid acceleration and hard braking), tire issues and proper maintenance.
방문운전연수Besides saving money at the pump, driving a fuel efficient vehicle can also help reduce our dependence on oil and contribute to environmental protection.
Aerodynamics
The shape of a vehicle and how it moves through the air can make a big difference in its fuel efficiency. The best way to achieve good aerodynamics is to use a design that reduces the coefficient of drag (Cd) as much as possible. This involves using a combination of factors, including the frontal area and surface area, curvature, weight, and air density.
The power needed to overcome aerodynamic drag increases with the square of the speed, so reducing drag can have a significant effect on fuel economy. For example, a two-litre Sierra developing 100bhp can reach about 115mph with a Cd of.26, whereas a car with twice the engine power can only go at about 145mph due to its larger frontal area and higher Cd.
The study of aerodynamics is part of fluid dynamics, but it can also be considered a subfield of gas dynamics. In addition to being important in automobile design, aerodynamics is useful in engineering applications, such as wind load calculations for bridges and tall buildings, and in designing piping systems for heating and ventilation.
Engine
The engine in your car is the heart of the fuel efficiency equation. Your engine uses gasoline to create the energy that drives your car forward, while also producing heat for other functions such as heating and air conditioning. The cylinders in your engine are hollow metal tubes that hold gas and air, which is compressed and ignited by an electric spark to produce the mechanical energy that moves your car.
The fuel efficiency of a vehicle power train is the ratio of tractive energy (plus idling and accessories) to its total energy input. 방문운전연수 Engine brake thermal efficiency is the fraction of engine power output (Pb) that is used for braking and accessory requirements, divided by its indicated horsepower (Pi).
The EPA certification tests are designed to simulate the most common driving conditions in real life. However, there are a number of factors that can decrease your real-world MPG. For example, towing a trailer and running electrical accessories increase your fuel usage. And a clogged mass air flow (MAF) sensor can prevent your engine from receiving the correct amount of fuel, decreasing performance and efficiency.
Transmission
A car’s transmission, or gearbox, is designed to reduce engine output speeds and increase the torque that can be applied to the wheels. Transmissions accomplish this via a series of clutches and gear sets that multiply engine power through shifting gear ratios. This allows the vehicle to operate within a much narrower range of RPMs, keeping the engine closer to its most efficient and economical sweet spot.
Achieving maximum fuel efficiency out of a conventional gas engine requires keeping the engine revs low. Having a larger number of gears in a transmission makes it easier to achieve this goal, as the engine can shift more quickly between different gears, staying lower in its most efficient operating range.
There are other ways to improve a transmission’s fuel economy beyond simply increasing its number of gears, including reducing parasitic losses. However, these improvements may come with a cost in terms of durability. This is an issue that is being considered by a growing number of consumers as they shop for a new car.
Brakes
Brakes are one of the most energy-efficient components in your car. They convert kinetic energy into thermal energy through friction by squeezing and pressing your tires’ metal disc or drum against the brake pad. Each wheel of your vehicle generates enough heat at a stop to boil a liter of water in seven seconds.
The most efficient braking systems use high-performance pads and premium rotors. However, a rotor’s performance is influenced by the type of brake fluid used. Glycol-ether fluids dissipate less power, while silicone-based fluids absorb more.
In a normal driving situation, your footbrake is the most common way to slow down and stop. However, slamming on the brakes wastes fuel. In fact, researchers have found that aggressive braking can decrease fuel efficiency by up to half a gallon.
To maximize your fuel efficiency, drive at a moderate speed and avoid slamming on the brakes. Instead, try to accelerate gradually and give yourself ample room between you and the driver in front of you when accelerating, braking, or changing lanes. This “brakeless” deceleration can help you save fuel and reduce the wear and tear on your brakes.
Tires
Despite the fact that many drivers are on a perpetual quest for secrets, miracle cures, and rising prices to lower their fuel consumption, there are some simple steps they can take. Regular maintenance, safe reasonable driving, and a good choice of vehicle design all contribute to better fuel efficiency. But the tires on your vehicle also play a big role in its overall performance.
Tires experience a lot of force during driving, and their shape changes constantly as they deform and recover from the road surface. This cycle releases energy that would otherwise be available to turn the wheels and wastes it through heat in the tire. To cut that loss, manufacturers use advanced rubber compounds formulations and tread designs.
Rolling resistance accounts for about 30-33% of a truck’s total fuel costs. Tread depth can have a big impact on that cost, with shallow-tread ribs saving the most. Other factors include the type of casing and whether it’s retreaded. Some makers are even experimenting with a plant-based substitute for natural latex (such as Russian dandelion and guayule), to reduce the carbon footprint of their products.