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Energy efficiency
Published in Kornelis Blok, Evert Nieuwlaar, Introduction to Energy Analysis, 2020
Kornelis Blok, Evert Nieuwlaar
Cars and other vehicles are tested using standard driving cycles. Such a standard driving cycle consists of a sequence of starts, accelerations, driving at a variety of constant speeds and stops. A test is carried out in two steps. First, the aerodynamic and rolling resistance is measured through a coast-down test: the car is brought to speed, and subsequently is left to decelerate. The rate of deceleration is a measure for resistance. Second, the fuel consumption is measured by putting the car on rollers connected to a dynamometer that simulates the standard driving cycle. The results of the first step are used as input for this second step. For cars the actual fuel consumption on the road deviates from the results of the test procedure – and is often higher. Therefore, new and more complex test procedures are developed to better approximate real-life conditions (see Figure 10.3).
Vehicle Dynamics
Published in Richard E. Neapolitan, Kwang Hee Nam, AC Motor Control and Electrical Vehicle Applications, 2018
Richard E. Neapolitan, Kwang Hee Nam
A driving cycle is a standardized driving pattern designed to test the efficiency of vehicle engines or drive trains. The pattern is a speed-time table which stands for urban stop-and-go trips or relatively smooth highway cycles. The US Environmental Protection Agency (EPA) developed the Federal Test Procedure (FTP75) to assess the performance of vehicles, such as fuel consumption and polluting emissions. The urban portion of the FTP75 is taken as the urban dynamometer driving schedule (UDDS). The UDDS, often called LA-4 or FTP72 cycle, has the high percentage of stop and acceleration/deceleration, and the maximum speed is less than 100 km/h. A hybrid power train can show a significant gain in fuel economy with the UDDS.
Lubricant Contribution to Energy Efficiency
Published in Don M. Pirro, Martin Webster, Ekkehard Daschner, Lubrication Fundamentals, 2017
Don M. Pirro, Martin Webster, Ekkehard Daschner
In Europe, the New European Driving Cycle is used to quantify vehicle emissions. The test method uses a complete vehicle that is run on either a flat road or a stationary roller test system capable of simulating aerodynamic drag. The test is started using a cold vehicle (20–30°C), which is then driven through a sequence of four urban driving cycles followed by an extra urban driving cycle. The test sequence captures the warming up effects associated with a relatively cold start and has been shown to favor use of lower viscosity lubricants. Since the test was originally conceived, vehicle power and driving styles have changed, and there have been concerns raised on the ability of the procedure to reproduce results relevant to current vehicle use. A harmonized world light vehicles test procedure (WLTP) is under development as a likely replacement.
Multi-objective calibration of traffic microsimulation models
Published in Transportation Letters, 2019
Glareh Amirjamshidi, Matthew J. Roorda
A driving cycle is a representative speed-time profile for a study area within which a vehicle can be idling, accelerating, decelerating, or cruising. Driving cycles vary across cities due to each city’s unique topography and road driving behavior and they have been shown to vary by vehicle type, time of day, and type of road. A driving cycle is made up of micro-trips, where each micro-trip is defined as the trip made between two idling periods (Hung, Tong, and Lee 2007; Kamble, Mathew, and Sharma 2009; Saleh et al. 2009; Yu et al. 2010). Figure 3 shows the method used for developing a driving cycle, where inputs are the second-by-second vehicle speed and location information. In this figure, teststatk is the kth assessment measure for the candidate driving cycle, tarstatk is the kth target assessment measure, and wk shows the importance of the kth measure relative to the other 12. Current literature on driving cycles considers all measures equally important (wk = 1) (Hung, Tong, and Lee 2007; Saleh et al. 2009). The PV is calculated for all candidate driving cycles, and the candidate with the lowest PV is selected as the final driving cycle for the particular vehicle/road type. More detail on the literature and the method used here can be found in Amirjamshidi and Roorda (2015).
Particle emissions measurements on CNG vehicles focusing on Sub-23nm
Published in Aerosol Science and Technology, 2021
Zisimos Toumasatos, Anastasios Kontses, Stylianos Doulgeris, Zissis Samaras, Leonidas Ntziachristos
Tests were performed on a chassis dynamometer using real-world road load settings, which were determined by an on-road coast-down test. In order to cover an extensive engine operation, the test protocol comprised the current and previous type approval driving cycles (Worldwide Harmonized Light Vehicle Test Cycle - WLTC and New European Driving Cycle -NEDC) as well as non-regulated ones such as ERMES, Artemis, simulated RDE and steady-state operating points at 80 km/h. Tests were first conducted with the CNG fuel, as this was the primary fuel. No on-demand selection of fuels was possible for testing. Following CNG depletion, each vehicle automatically switched to back-up gasoline operation. Any auxiliary device including the Start/Stop system was deactivated during the tests.
A review on fuel cell electric vehicle powertrain modeling and simulation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Eda Alpaslan, Sera Ayten Çetinkaya, Ceren Yüksel Alpaydın, S. Aykut Korkmaz, Mustafa Umut Karaoğlan, C. Ozgur Colpan, K. Emrah Erginer, Aytaç Gören
The powertrain system modeling of the vehicles in the longitudinal drive cycle simulation method requires drive cycle characteristics for the input parameters of the simulation including vehicle speed and acceleration. In the drive cycle simulation studies, a driving cycle is defined in the simulation model. This driving cycle can be standard or special drive cycles (e.g., NEDC, WLTP, etc.) as well as cycles including traffic conditions such as testing roads (e.g., Manhattan Bus Cycle, Demonstration Test Cycle). Driving cycles have been developed to study the performance and pollutant emissions of different types of vehicles (light or heavy speed) using a chassis or an engine dynamometer. These cycles have been arranged in different road conditions (urban, rural loads, military terrain) depending on the area of use of the vehicle, but urban driving cycles are the most used and most important cycles of chassis dynamometer tests (Lin and Niemeier 2003). Representing the typical use of a car for urban use in Europe, the NEDC (New European Driving Cycle) consists of a four-times repeated European Economic Commission-15 (ECE-15) urban driving cycle and an Extra Urban Driving Cycle (EUDC) (Yang et al. 2014). The NEDC driving cycle includes a range of tolerances and flexibility in terms of automobile fuel consumption and CO2 emissions and no longer accurately reflects the latest technologies (Mock et al. 2014). Therefore, the WLTP (World-wide harmonized Light-duty Test Procedure) driving cycle was developed by the European Union (EU) in 2017 (Tutuianu et al. 2015). On the other hand, the US urban dynamometer driving program (UDDS) driving cycle is one of the few chassis-dynamometer cycles globally recognized as legal for heavy-duty vehicles.