【正文】 model as closely matched as possible. Each vehicle was run through a series of tests, explained briefly below. Each of these procedures has a page, on the ve lapsed time from 40 to 60 mph at wide open throttle (passing simulation)。 (3) elapsed time and maximum speed at a quarter mile. Values are the average of six evaluation website, with detailed descriptions. Acceleration: Three tests performed: (1) elapsed time from a standstill to 60 mph at wide open throttle, loaded and unloaded。 (2) e Braking: Dry surface is concrete, wet surface is low friction Jennite pad. Minimum stopping distance from 62 mph (100 km/h) on dry surface, and from 31 mph (50 km/h) on wet surface with no wheels locked. Panic stops are minimum measured distance from 31 mph (50 km/h) on wet and dry surfaces at maximum pedal pressure with no attempt to steer. Values are average of six stops. Fuel Economy: City fuel economy determined using an urban driving cycle—a distance of 2 miles with 8 stops. Highway fuel economy used a 70 mph average driving cycle with no stops. The 150 mile trip alternated between urban and highway cycles until 150 miles was reached. Results are reported in 70% highway driving for total trip. Cold Start: Vehicle placed in a temperaturecontrolled room at 20176。F for first test (minimum soak time 12 hr*). Crank time and idle rating recorded. If start successful, procedure repeated at 20176。F for confirmation. If start unsuccessful, procedure repeated at higher temperature until minimum temperature is determined. Driveability and Handling: Four different drivers rated each aspect of the vehicles。 final rating is average of the four. Emissions: Duplicate tests performed on each vehicle using EPA’s Federal Test Procedure. CNG Civic tested on CNG, gasoline Civic tested on RFA (industry average gasoline). *Soak time allows the vehicle to stabilize at a given temperatureBeginning with the 1998 model year, Honda has equipped its popular Civic sedan with a Inline 4 cylinder dedicated natural gas engine. Honda chose the Civic to be its first natural gas vehicle because of its low cost and high fuel efficiency. Extensive research by Honda lead to a CNG dedicated engine designed for optimized performance on natural gas. Features of the vehicle include an increased pression ratio and specially formulated 3way catalysts. The gasoline Civic was certified to low emission vehicle standards (LEV), but the CNG Civic was designed to have emissions levels that are 1/10 ultra low emission vehicle standards (ULEV).General Description:Engine:DisplacementConfigurationTransmissionFuel SystemEngine Family CodeCompression RatioCNG XCNG Civic GX literInline 44speed automaticMultiport fuel injection:1Gasoline Civic LX literInline 44speed automaticMultiport fuel injection:1Capacities:FuelPassengersTrunk Space (cu ft)8 equivalent gal2 front/2 rear12 gal2 front/3 rearDimensions:LengthWidthCurb Weight in in2599 lbs in in2456 lbsOther features: Both vehicles were front wheel drive sedans equipped with air conditioning, power steering, power brakes, power door locks and windows, tilt wheel, and cruise control. The CNG Civic was also equipped with an antilock braking system (ABS), which is not standard on the gasoline vehicle. The gasoline model tested had a standard power brake system.Performance:Acceleration060 mph loaded (sec)060 mph unloaded (sec)40 to 60 mph (sec)1/4 mile time (sec)1/4 mile speed (mph)CNGGasolineFuel Economy (mpg)CityHighwayCombined City/HighwayBrakingEffectiveness stops:62 mph (100 kph)dry pavement31 mph (50 kph)wet jenitePanic stop31 mph (50 kph)dry pavement31 mph (50 kph)wet jeniteCNGwith ABS)meters feet Gasoline(without ABS)Meters feet Cold StartTemperature 176。F2015Crank time idle rating _4 sec 6Crank time idle rating 48 4Evaluation SummaryEvaluation results from a dedicated CNG Civic and a gasoline Civic showed very little difference in acceleration, and driveability and handling. Evaluators reported that both vehicles handled well, but that the gasoline control had slightly better acceleration. The trunk space is significantly reduced for the CNG Civic because the CNG fuel cylinder is installed in the trunk. During the braking tests on dry pavement the Civics performed nearly identically, but the CNG Civic outperformed the gasoline vehicle on the wet surface. This was not surprising since the gasoline Civic was not equipped with ABS, and the CNG Civic was. It is expected that performance for the wet braking tests would have been similar if both vehicles had ABS. The results revealed fuel economy as much as 8% higher for the CNG Civic pared to the gasoline Civic. Engine design changes, including operating at a higher pression ratio, likely contribute to higher overall efficiency and improved fuel economy of the CNG Civic. During cold start testing, the CNG Civic started at –20 degrees the first time, but failed to start in 2 subsequent tests. The test at –15 degrees was successful. The gasoline model started in both –20 degree tests. Emissions test results showed one of the biggest benefits of the CNG Civic. Although the emissions measured from both vehicles were low for the regulated constituents, those from the CNG Civic were at or below 1/10 the ULEV certification level. Emissions of potency weighted toxics (including: benzene, 1,3butadiene, formaldehyde, and acetaldehyde)* for the CNG Civic were 97% lower than that of the gasoline Civic.Firstly, parison of natural gas vehicle (CNG) fue