Search Results (3)

Brake particle emissions number (PN) and mass (PM) of a light-duty hybrid-electric vehicle have been assessed under realistic driving patterns on a chassis dynamometer. Therefore, the front-right disc brake was enclosed in a specifically designed casing featuring controlled high scavenging air ventilation. The WLTC cycle was chosen for most measurements. Different scavenging flow rates have been tested assessing their influence on the measured particles as well as on the temperature of the braking friction partners. Particle transport efficiencies have been assessed revealing scavenging flow rates with losses below 10%. During the performed cycle, most brake particle emissions occurred during braking. There were also isolated emission peaks during periods with no brakes in use, especially during vehicle accelerations. Sequential WLTC cycles showed a continuous decrease in the measured PN and PM emissions; however, size-number and size-mass distributions have been very similar. The measured PN emission factors (>23 nm) at the right front wheel over the WLTC cycle lie at 5.0 × 10¹⁰ 1/km, whereas the PM emission factor lies at 3.71 mg/km for PM < 12 µm and 1.58 mg/km for PM < 2.5 µm. These values need to roughly triple in order to obtain the brake particle emission of all four brakes and wheels of the entire vehicle. Thus, the brake PN emissions factors have been in the same order of magnitude as the tailpipe PN of a Euro 6 light-duty vehicle equipped with a particle filter. Finally, differences between brake particle emissions in hybrid and all-electric operating modes have been assessed by a series of specific measurements, demonstrating the potential of all-electric vehicle operation in reducing brake particles by a factor of two. Full article

The relative fuel consumption reduction strengths of multiple passenger car powertrains are investigated. These include [A] conventional compression ignition (CI) direct injection (DI) turbocharged (TC) diesel (D) [CI-DI-TC-D]; [B] Atkinson cycle charge sustaining (CS) “split-hybrid” electric vehicles (HEV) fueled by gasoline/petrol (G) [HEVG]; plug-in (P) hybrid gasoline/petrol [PHEVG)]; and indirect fuel injected (IDI) spark-ignited (SI) internal combustion engines (ICE) fueled by gasoline/petrol [SI-IDI-NA-G]. When we use simulation to evaluate the behavior of PHEVG powertrains, the size is a four-to-five passenger car platform that would be regarded as “compact” in the U.S. and standard in Europe. A careful distinction between probable driving patterns for PHEVGs when in charge-depletion (CD) mode vs. charge sustaining (CS) operation is made. Effects of variation in the amount of kWh storage and the CD strategy, between PHEVs with varying km of electric-equivalent range are also investigated. The effect of electric drive (battery and motor) power (kW) on ability of a vehicle to operate all-electrically, relative to its ability to reduce oil use, is examined. Four degrees of hybridization are briefly examined, including stop-start (SS), integrated starter-generator (ISG), mild parallel (MP), and full parallel (FP). Each of the parallel PHEVs examined is an FP. Powertrain model simulations and limited dynamometer test results for such PHEVGs are compared to the other vehicle types for certification and “on-road” driving cycles from Europe and the U.S. It is illustrated that the conventional wisdom that HEVG has significant superiority over CG primarily in urban stop and go driving should not automatically be extended to PHEVGs. The driving cycle information is related to systematically varying consumer patterns of dwelling choice and vehicle use in cities, suburbs, and rural areas, as well as across nations. Effects of fuel taxation choices by nation — for gasoline, diesel and electric fuel — are investigated. The effects that residential location and type, driving cycle, and fuel cost have on the relative marketability of the studied powertrains, when initially entering the market, are summarized. The sequence of events leading to early emergence of original equipment automaker production and marketing of PHEVGs is discussed. Full article

Estimation of the potential of plug-in hybrid electric vehicles’ (PHEV’s) ability to reduce U.S. gasoline use is difficult and complex. Although techniques have been proposed to estimate the vehicle kilometers of travel (VKT) that can be electrified, these methods may be inadequate and/or inappropriate for early market introduction circumstances. Factors that must be considered with respect to the PHEV itself include (1) kWh battery storage capability; (2) kWh/km depletion rate of the vehicle (3) liters/km use of gasoline (4) average daily kilometers driven (5) annual share of trips exceeding the battery depletion distance (6) driving cycle(s) (7) charger location [i.e. on-board or off-board] (8) charging rate. Each of these factors is actually a variable, and many interact. Off the vehicle, considerations include (a) primary overnight charging spot [garage, carport, parking garage or lot, on street], (b) availability of primary and secondary charging locations [i.e. dwellings, workplaces, stores, etc] (c) time of day electric rates (d) seasonal electric rates (e) types of streets and highways typically traversed during most probable trips depleting battery charge [i.e. city, suburban, rural and high vs. low density]; (f) cumulative trips per day from charger origin (g) top speeds and peak acceleration rates required to make usual trips. Taking into account PHEV design trade-off possibilities (kW vs. kWh of battery, in particular), this paper attempts to extract useful information relating to these topics from the 2001 National Household Travel Survey (NHTS), and the 2005 American Housing Survey (AHS). Costs per kWh of PHEVs capable of charge depleting (CD) all-electric range (CDE, or AER) vs. those CD in “blended” mode (CDB) are examined. .Lifetime fuel savings of alternative PHEV operating/utilization strategies are compared to battery cost estimates. Full article