Federal test cycle

This model can be used to study the entire Federal Test Cycle covering many hours of operation of the catalytic converter. 

Fuel economy, typically expressed as distance driven per volume of fuel consumed, ie, ia km/L (mi/gal), is measured over two driving cycles specified by the Federal Test Procedure (63). Oae cycle simulates city driving and consists of relatively low speed (- 32 km/h) driving, and iacludes a portion where the car starts after having equiUbrated at ambient conditions for 16 hours. The second simulates highway driving conditions and iacludes higher speeds and... 

The possibility of artifactual formation of nitro-PAHs during the sampling of diesel exhaust was addressed soon after their discovery in diesel particles (e.g., Lee et al., 1980 Lee and Schuetzle, 1983). Schuet-zle (1983) concluded that artifactual formation of nitro-PAHs is a minor problem (between 10 and 20% of the measured 1-nitropyrene) at short sampling times [e.g., 23 min, which is one federal test procedure (FTP) driving cycle], at low sampling temperatures (42°C), and in diluted exhaust containing NOz. 

FTP Federal Test Procedure a standard US drive cycle... 

Figure 1 Speed/time trace for the U.S. federal test procedure (FTP). The American test cycle for passenger cars and light-duty vehicles from 1975 model year.

A good way to get a feel for the dynamic nature of automotive catalyst operation is to look at a plot of speed versus time during the U.S. Federal Test Procedure (FTP) as shown in Fig. 1. Clearly, steady-state conditions do not exist in this test, which simulates the acceleration and deceleration cycles of urban driving and which is similar to the European test procedure. 

Fig. 1. Plot of vehicle speed during the urban driving cycle of the U.S. Federal Test Procedure (FTP).

Comp. - City/Highway composite, a weighted value composed of the results of one highway cycle and one Federal Test Procedure (FTP) cycle... 

Fig. 4. Cumulative hydrocarbon emissions measured during the federal test procedure (FTP cycle) on a US 1995 car (1) engine-out emissions (2) tailpipe emissions with close-coupled catalyst. (Heck and Farrauto 1997.)...

The formulation of emission factors for mobile sources, the major sources of VOCs and NO, is based on rather complex emission estimation models used in conjunction with data from laboratory testing of representative groups of motor vehicles. Vehicle testing is performed with a chassis dynamometer, which determines the exhaust emission of a vehicle as a function of a specified ambient temperature and humidity, speed, and load cycle. The current specified testing cycle is called the Federal Test Procedure (FTP). On the basis of results from this set of vehicle emissions data, a... 

Base line values for vehicle emissions (with air injection but without catalyst) were measured periodically during the catalyst test series. Base line values were determined with empty converters as well as with inert SiC filler pellets, and there was no discernible difference. The repeatability of the base line values is evident in Table I. Base line emissions are given for the 1975 Federal Test Procedure (FTP), for the first five cycles of operation (Bag 1), and for the hot, stabilized cycles 6-18 (Bag 2). These values thus reflect the overall vehicle emissions, emissions during warm-up, and emissions during stabilized vehicle operation, respectively. Catalyst system performance was assessed by comparison with the average base line emission values, Le. the latter were considered the converter inlet levels of HC and CO. 

The catalyst performance was evaluated by using the U.S. Federal Test Procedure. Since the key purpose of preconverter is to reduce the cold-start emissions, bag 1 of FTP cycle was split into two bags bag lA which represents 0 to 220 sec. and bag IB which represents 220-505 sec. However, at t = 220 sec. the temperature of the main converter is relatively stable and sufficiently high to ensure rapid reaction kinetics. 

In the USA, the Supplemental Federal Test Procedure (SFTP) is used to evaluate and compare fuel economy. It consists of the Federal Test Procedure (FTP75, Figure 35.8) and of two further test cycles. The FTP75 consists of the city driving cycle and the highway driving cycle [1]. 

The leading LD diesel non-methane HC and NOx regulations are graphically shown in Fig. 1.2. Only the US (Federal and CaUfomia LEVIII) has the test-cycle and limit value combination to force NOx aftertreatment. All require a DPF (regulations not shown). By 2013, perhaps a dozen diesel models will be on the US market. However, the majority of Euro 6 applications will have NOx aftertreatment to minimize NO2 emissions and fuel consumption. 

To validate the GT-Power model of the engine, the response of the model over a heavy duty FTP (Federal Test Procedure) drive cycle was compared to experimental data. In the simulation, the measured trajectories for the engine speed, the EGR valve position and the VGT position along with the command trajectories for the fueling parameters for the experimental drive cycle were imposed as inputs to the GT-Power model. For each of the relevant quantities, the predicted and experimentally measured values had very high correlations. The R correlations were 91.1% for the fresh air mass flow rate, 91.3% for the EGR mass flow rate, 90.9% for the oxygen concentration of the exhaust stream and 81.1% for the NOx production. To account for the dynamics of the NOx sensor, the GT-Power predictions were filtered with a first order filter and then compared to the measurement data. Figure 4 depicts how well the dynamic variation in each of these four quantities is captured by the GT-Power model for the first 100 seconds of the drive cycle. 

Fig. 1. Federal emission test driving cycle for 1972 and later model cars. (Federal Register, November 10, 1970).

The material was developed by the Research Institute of Electrocarbon Products (RIECP, Russian Federation) on the basis of natural graphite specially for application in Lithium-Ion cells. The samples were given with symbolic numbers, without certificates. The anodes, made of RIECP powder, had the capacity about 300 mA-h/g. The typical dicharge characteristic is submitted on Fig. 6. Irreversible capacity is about 16%. Concerning the cycle behavior, this material is not as stable as other ones tested (Fig. 10). 

Although catalyst deterioration for methane oxidation was clearly demonstrated in the laboratory test under steady-state conditions at 500°C, as shown in Fig. 15, it seems to be less discernible in car tests based on various driving cycles. Thus, data obtained on Ford vehicles, subjected to the 1977 Federal Certification Test over 50,000 miles, indicated that catalysts can be essentially inactive in removing methane even at zero miles, under these conditions. 

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