2024年3月5日发(作者：)

中英文文献翻译-低滚动阻力轮胎

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LOW ROLLING RESISTANCE TIRES According to the report,80%

or more of a car’s fuel energy is wasted by friction and other

such losses. 1.5 to 4.5% of total gasoline use could be saved if

allreplacement tires in use had low rolling resistance. About 237

million replacement tires are sold in the U.S. each year – none has

rolling resistance labeling.

1. America’s Fuel Use, Its Impacts,and Opportunities for

Savings

The environmental impacts of America’s gasoline use are

profound. With over 160 million passenger cars and light trucks

on the road, we burn about 126 billion gallons of gasoline per

year. Our fuel use continues to rise about 3% annually, propelled

by continued increases in total number of vehicles, rising average

distance driven per car, and falling average fuel economy.

Today, light-duty vehicles (cars & light trucks) are responsible

for about 20% of the nitrogen oxides, 27% of the volatile organic

compounds, 51% of the carbon monoxide, and roughly 30% of

all the carbon dioxide (the main greenhouse gas) emitted from

human activities nationwide. Rising fuel use also has enormous

implications for protection of wilderness and public lands

(vulnerable to increased exploration), water resources (vulnerable

to tanker and pipeline accidents), and national security. So the

opportunity to save money and improve environmental quality

through fuel use reductions is clear.

One of the most promising opportunities for fuel savings

across the entire fleet of existing vehicles is to utilize low rolling

resistance tires instead of standard replacement models. This

change improves the inherent efficiency of the vehicle,

automatically saving fuel over the typical 30,000 to 50,000 mile

lifetime of a set of tires.

This report examines the opportunity for saving gasoline

through use of improved tire technology and recommends

particular tire models for which our initial test data suggest

environmental advantages. Its findings are applicable to

government and corporate fleet managers as well as individual

tire buyers.

2. How Tires Can Reduce Fuel Consumption

According to the National Academy of Sciences, about 80 to

88% of the energy in a vehicle’s gasoline tank is wasted in

various thermal, frictional, and standby losses in the engine and

exhaust system. This leaves only about 12 to 20% of the potential

energy actually converted to vehicle motion. One of the key ways

to improve that efficiency is to reduce the rolling resistance of

vehicle tires. This is not a measure of a tire’s traction or “grip”

on the road surface, but rather simply indicates how easily a tire

rolls down the road, minimizing the energy wasted as heat

between the tire and the road, within the tire sidewall itself, and

between the tire and the rim.

Detailed modeling conducted by the National Renewable

Energy Laboratory concluded that a 10% reduction in tire rolling

resistance should yield fuel savings of about 1 to 2%, depending

on driving conditions and vehicle type. According to research for

the California Energy Commission, about 1.5 to 4.5% of total

gasoline use could be saved if all replacement tires in use had

low rollingresistance. This translates roughly into average savings

of up to 30 gallons of gasoline savings per vehicle per year, or

from $2.5 to $7.5 billion worth of national average gasoline

savings.

As part of their efforts to meet Federal fuel economy

standards, automakers routinely specify low rolling resistance

tires on their new vehicles. Between 1980 and 1994, the lowest

rolling resistance tire models available achieved a 48% reduction

in rolling resistance, and have likely continued to improve

thereafter. These original equipment (OE) tire models are

occasionally available in the replacement tire market, but often

only by special order. In general, the tires marketed to the

replacement tire market tend to place greater emphasis on

longevity and low price, and therefore often have higher rolling

resistance than OE tires.

Unfortunately both OE and replacement tires lack any sort of

rolling resistance labeling currently, so fleet managers and

consumers that wish to buy highly energy-efficient tires when

their first set of OE tires wear out have been stymied. Even when

tire makers claim that particular replacement models are more

fuelefficient than others, they do not always use consistent test

methods or independent laboratory data to back up those claims.

About 237 million replacement tires are sold in the U.S. each year

for cars and light trucks, and none of them provides rolling

resistance labeling.

In 2002, the Energy Foundation funded Ecos Consulting to

analyze the tire market, select representative models for rolling

resistance testing, and work with Green Seal to recommend

particular models that perform well while achieving low rolling

resistance.

Those findings are being published for the first time in this

Choose Green Report. Additional background on Ecos

Consulting’s key findings can be found in a separate report

prepared for the California Energy Commission, available at

/doc/,/reports/2003- 01-31_.

3. Balancing Tire Resistance and Other Considerations

The manufacture of tires, like other industrial processes,

involves material extraction and production, as well as energy

consumption and the emission of various pollutants. Each of

these manufacturing stages impacts the environment in different

ways. However, tires, like a number of other consumer products,

are actually responsible for more environmental impacts in their

use and ultimate disposition than in their manufacturing. They

significantly impact the amount of fuel consumed by the vehicle

to which they are attached, leading to global warming emissions

as well as local and regional air pollution. They create particulate

air pollution in the process of wearing, and they can be a

significant solid waste problem if not properly recycled.

An analysis conducted by Italian tire manufacturer Pirelli

(Figure 1) revealed the dominance of tire use in overall life-cycle

energy consumption. Fully 82% of the lifecycle energy use occurs

from the tire’s contribution to vehicle fuel use, compared to

roughly 18% associated with obtaining the raw materials and

manufacturing the tire itself. Thus, a tire’s rolling resistance is

likely to be a larger factor in its life-cycle environmental impact

than its composition, longevity, or ultimate fate, though those

factors merit consideration as well.

This report places greatest significance on the measured

rolling resistance of tires, followed closely by consideration of the

tire’s expected longevity and performance characteristics. A tire

with high rolling resistance can cause profound environmental

impact, even if it capably grips the road and lasts for 80,000 miles.

By contrast, a very low ro lling resistance tire may not be worth

recommending if its lifetime is unusually short or test data

indicate that it provides poor traction.

Every tire currently on the market represents a balance

between a wide assortment of desired performance

characteristics and price (we surveyed tires ranging from $25 to

over $200 per tire). Careful balancing of these characteristics can

yield not only a high-performing tire, but also one that is better

for the environment than others currently available on the market.

Tire Rolling Resistance and Related Factors

Rolling resistance has traditionally been measured through

an official Society of Automotive Engineers (SAE) test procedure

known as J1269. It measures the force required to roll a tire

against a dynamometer at a fixed speed of 50 miles per hour. A

newer procedure, SAE J2452, promises improved accuracy by

assessing rolling resistance at a variety of speeds, but no

independent laboratory currently has the capability to conduct

such testing in-house. As a result, all of our testing was

conducted at a single independent laboratory according to SAE

J1269.

The highest and lowest rolling resistance tires we tested

differed in efficiency by 60%, indicating that tire choice can have

a bigger impact on fuel economy than most people realize.

Rolling resistance differences of 20 to 30% are not uncommon

among tires of an otherwise similar size, type, and level of

performance. This means an individual vehicle could save up to

6% of its gasoline use if it were fitted with very efficient tires,

paying for the modest additional cost of low rolling resistance

tires in approximately a year of fuel savings. In other words, a

typical compact car such as a Ford Focus can improve its mileage

from 30 mpg to 32 mpg simply by using lower rolling resistance

tires. For a car averaging 15,000 miles per year the fuel savings is

about $50 (at $1.50 per gallon).

All tires have imprinted information on their sidewalls

indicating size, type, load, and speed ratings, as described in

Figure 2. The majority of tire models employ a “P” designation

for passenger vehicle use, but some bear the “LT” designation

for use with light trucks. In general, “P” tires appear to be

gaining in popularity relative to “LT” tires of a given size.

In addition, the U.S. Department of Transportation requires

each manufacturer to grade its tires under the Uniform Tire

Quality Grading System (UTQGS) and establish ratings for the

following characteristics: tread wear, traction, and temperature

resistance. Unfortunately, the ultimate results published for each

tire model are less “uniform” than they should be. The

government specifies how each test should be conducted and

prevents a manufacturer from claiming better performance than

measured. However, it does not prevent manufacturers from

claiming worse performance than measured. And, curiously

enough, many do, primarily to amplify marketing distinctions

among their tires at different price points and encourage buyers

to move up from a “good” to a “better” or “best” mode l

in a particular category.

Given the variability of ratings and the number of relevant

factors, we have compiled our own composite metrics of

performance for assessing tires, including the Federal ratings

noted below and a variety of other published data.

g On to the Future

Efforts to differentiate replacement tires on the basis of

rolling resistance are still in their very early stages. Without data

on the rolling resistance of all tire models across a range of sizes,

it is impossible to say for sure if the models identified in this

report represent the most efficient models or simply a subset of

them. For now, consumers and fleet managers can start with the

data shown here and request additional information directly

from retailers and manufacturers.