Harmonized Light Duty Test Cycle Research Articles

Research regarding the simulation of the autonomy for the electric vehicles in the case of the WLTC test cycle

Abstract In current mainstream research, energy consumption and autonomy are just a few of the the major objectives anticipated for electric road vehicles. The production of electric vehicles is continuously expanding, offering to the market a large variety of constructive variants in order to satisfy the requirements for their exploitation. Also, in the current energy context, it is expected from the electric car manufacturers, to deliver high quality models which can be characterized as the actual alternatives to actual existing solutions equipped with an internal combustion engine. Under these circumstances, the continuous research it is a high priority for everyone electric vehicle producers, where simulation on the computer is basically not absent as a go-between step prior to the validation of the final draft proposals. According to these assumptions, in the first part of the article you will find the AMESim simulation platform points, where it describes the model made with it and the simulated test cycle. In the second part of the article, as a consequence of the simulation of the experimental electric vehicle, are highlighted some aspects of the autonomy behaviour in the case of simulation on the World-wide harmonized Light duty Test Cycle (WLTC), for all four speed zones specific to it.

Particulate matter emissions from light-duty gasoline vehicles under different ambient temperatures: Physical properties and chemical compositions

Fine particulate matter (PM2.5) from vehicle exhaust is typically emitted at breathing height and thus imposes severe adverse effects on human health and air quality. However, there is currently limited knowledge on the characteristics of PM2.5 in exhaust, specifically its chemical components, at different ambient temperatures. Particulate emissions from typical light-duty gasoline vehicles (LDGVs) were investigated on a chassis dynamometer according to the Worldwide Harmonized Light-Duty Test Cycle at ambient temperatures of 38 °C, 28 °C, 15 °C, 5 °C and − 7 °C. The results showed a significant increase in particulate mass (PM) and particle number (PN) emissions with decreasing ambient temperature, particularly during cold starts below 5 °C. The particle size distributions exhibited distinct bimodal patterns, with accumulation-mode (AM) particles (60–125 nm) dominating the gasoline direct injection (GDI) distribution and nucleation-mode (NM) particles (8–12 nm) dominating the port fuel injection (PFI) distribution. AM particles were more temperature-sensitive than NM particles. Lower temperatures produced higher emissions of elements, carbonaceous components, and large-ring polycyclic aromatic hydrocarbons, while water-soluble ions showed an opposite trend. The total toxic equivalent, primarily influenced by benzo[a]pyrene, was significantly higher at −7 °C. The penalty distribution of LDGV PM and PN, defined by comparing the emissions at the various temperatures to those at regulated temperatures (23–30 °C), exhibited notable temporal heterogeneity (winter > autumn > spring > summer) and spatial heterogeneity (northern China > southern China). These findings are essential for establishing more stringent vehicle emission standards and improving emission models in cold environments.

The Assessment of PM2.5 and PM10 Immission in Atmospheric Air in a Climate Chamber during Tests of an Electric Car on a Chassis Dynamometer

Electric cars, like internal combustion vehicles, emit particulate pollution from non-exhaust systems, i.e., tires and brakes, which is included in the Euro 7 emission standard planned for implementation. Tests conducted on chassis dynamometers are accompanied by particulate emissions from non-exhaust systems, which are introduced into the ambient air on the test bench. Particulate emissions tests from non-engine systems on chassis dynamometers are mainly aimed at measuring the mass or number of particulates from tires and brakes. In contrast, little attention is paid to the immission of particulate matter from tires and brakes on the dynamometer during tests, which in the case of electric cars include, for example, measurements of energy consumption or range. Therefore, in order to draw attention to the problem of these emissions, the authors carried out measurements of PM2.5 and PM10 immissions into the air in the climatic chamber during tests of an electric car on a chassis dynamometer. The car tests were carried out in accordance with the WLTC (Worldwide harmonized Light duty Test Cycle) and at constant speed. Based on the test results, a model was proposed for the immission of particulate matter in laboratory air from tire and brake abrasion, taking traffic parameters into account. The results and the developed model show that air quality, in terms of particulate content, deteriorates significantly during testing.

A methodology to develop multi-physics dynamic fuel cell system models validated with vehicle realistic drive cycle data

Fuel cell (FC) technology has been identified as a technically attractive solution to decarbonize the transportation sector, especially for heavy-duty vehicles. In this context, the industry and the scientific community are in need of advanced fuel cell systems (FCS) models that are able to replicate real-world operating conditions. Due to the scarcity of said models in the open literature, this study aimed to develop a comprehensive methodology to calibrate and validate multi-physics dynamic FCS models. Therefore, the key contribution of this paper is the detailed description of the calibration process for each component and the calibration order. The specific focus here was to accurately describe the behavior of the FC stack as well as the cathode, anode, and cooling circuits of the balance of plant. The model was calibrated with the aid of experimental data from a Toyota Mirai FC electric vehicle, which was predominantly retrieved from the vehicle’s Controller Area Network (CAN) bus system thereby negating the need for major intrusion into the powertrain system. The validation process was deemed successful with the model being able to truthfully replicate the characteristics of the FC vehicle operated on the World-wide harmonized Light duty Test Cycle (WLTC) 3b and US06 driving cycle. The time-resolved physical parameters such as the cathode pressure, mass flow, or the FC stack temperature were captured with high fidelity, while the overall performance parameters such as the H2 consumption in the stack and the system, and the compressor energy consumption were predicted accurately with a deviation lower than 0.47%, 1.75% and 1.89% with respect to the experimental data, respectively.

Assessment of the Effect of Road Load on Energy Consumption and Exhaust Emissions of a Hybrid Vehicle in an Urban Road Driving Cycle—Comparison of Road and Chassis Dynamometer Tests

Differences between the results obtained in laboratory and road tests of vehicles depend on a number of factors. Among the most important of these are driving cycle and road load. These parameters also affect the hybrid drive control, including the combustion engine operation or driving in electric mode. In most studies, tests carried out on chassis dynamometers concern type approval cycles (NEDC—New European Driving Cycle, WLTC—World-wide harmonized Light duty Test Cycle, FTP— Federal Test Procedure), which differ from real on-road tests. Consequently, the different driving cycles do not allow for results similar to those obtained during on-road driving, especially as the actual cycles on the road are unrepeatable. It is also important to determine the effect of the motion resistance function adopted for chassis dynamometer tests on exhaust emissions and fuel consumption. For this purpose, the authors tested a hybrid car under road and laboratory conditions for the same driving cycle. The analysis was conducted for an example urban road cycle in Rzeszow (URRC). The purpose of the study was to determine the differences in the results of gaseous emissions (THC, CO, CO2, NOx) and fuel consumption (energy) of a hybrid car under road conditions, with the results of tests conducted on a chassis dynamometer, for the same cycle and three functions of resistance.

A novel thermal management system with a heat-peak regulator for fuel cell vehicles

Thermal management of fuel cell vehicles is posing a constant challenge due to the growing installed power of the fuel cell stack and consequent heat-overloaded situations of the radiator. Based on the “time-dependent” idea that considers the fluctuated heat generation and the intermittent heat peak during the journey, a novel thermal management system that employs a heat-peak regulator is proposed in the present work. The heat-peak regulator is a thermal accumulator filled with phase-change material that separately exchanges heat with the fuel cell coolant and the air conditioner refrigerant. It temporarily receives the excess heat that cannot be released out by the radiator when the heat peak occurs; later on, when the heat peak is gone, the heat is transferred to the refrigerant to remove it from the condenser. The system simulations based on the developed thermal models demonstrate that, the thermal runaway of the fuel cell stack can be eliminated or effectively weakened by this novel thermal management system, relying on the amount of the phase-change material filling the heat-peak regulator. In the present study, the 135 s and 250 s thermal runaway durations can be shortened to 0 s and 105 s, respectively, in the standardized New European Driving Cycle and World-wide Harmonized Light Duty Test Cycle under 38 °C summer weather, and the maximum temperature for the latter can be reduced from 89 °C to 83 °C. This work can make a significant contribution towards the solution of thermal management problems of the fuel cell vehicles.

Modeling and Simulation of Extended-Range Electric Vehicle with Control Strategy to Assess Fuel Consumption and CO2 Emission for the Expected Driving Range

Extended-Range Electric Vehicles (EREVs) are intended to improve the range of battery electric vehicles and thus eliminate drivers’ concerns about running out of energy before reaching the desired destination. This paper gives an insight into EREV’s performance operating according to the proposed control strategy over various driving cycles, including the Worldwide Harmonized Light-duty Test Cycle Class 3b (WLTC 3b), Federal Test Procedure (FTP-75), and China Light-Duty Vehicle Test Cycle (CLTC-P). Simulation runs were performed in Matlab-Simulink® for different cases of drive range, electricity mix, and vehicle mass. The control strategy goal was to aim at a specified value of battery state of charge at the targeted range value. The obtained test results included: pure electric drive range, acceleration times, EREV range tests, control strategy range errors, Range Extender (REX) utilization metric and distribution of its engagement instances, fuel consumption, total equivalent CO2 emission, powertrain efficiency, and specific energy consumption. The control strategy operated on average with a range error of −1.04% and a range mean square error of 2.13%. Fuel consumption (in range extension mode) varied between 1.37 dm3/100 km (FTP-75) and 6.85 dm3/100 km (WLTC 3b Extra-High 3). CO2eq emission was 95.3–244.2 g/km for Poland, 31.0–160.5 g/km for EU-27, and 1.2–147.6 g/km for Sweden. This paper is a valuable source of information for scientists and engineers seeking to learn the advantages and shortcomings of EREV drives with a proposed control strategy, based on various sets of results.

Driving Cycles for Estimating Vehicle Emission Levels and Energy Consumption

Standard driving cycles (DCs) and real driving emissions (RDE) legislation developed by the European Commission contains significant gaps with regard to quantifying local area vehicle emission levels and fuel consumption (FC). The aim of this paper was to review local DCs for estimating emission levels and FC under laboratory and real-world conditions. This review article has three sections. First, the detailed steps and methodologies applied during the development of these DCs are examined to highlight weaknesses. Next, a comparison is presented of various recent local DCs using the Worldwide Harmonized Light-Duty Test Cycle (WLTC) and FTP75 (Federal Test Procedure) in terms of the main characteristic parameters. Finally, the gap between RDE with laboratory-based and real-world emissions is discussed. The use of a large sample of real data to develop a typical DC for the local area could better reflect vehicle driving patterns on actual roads and offer a better estimation of emissions and consumed energy. The main issue found with most of the local DCs reviewed was a small data sample collected from a small number of vehicles during a short period of time, the lack of separate phases for driving conditions, and the shifting strategy adopted with the chassis dynamometer. On-road emissions measured by the portable emissions measurement system (PEMS) were higher than the laboratory-based measurements. Driving situation outside the boundary conditions of RDE shows higher emissions due to cold temperatures, road grade, similar shares of route, drivers’ dynamic driving conditions, and uncertainty within the PEMS and RDE analysis tools.

Primary organic gas emissions from gasoline vehicles in China: Factors, composition and trends

Continuous tightening emission standards (ESs) facilitate the reduction of organic gas emissions from gasoline vehicles. Correspondingly, it is essential to update the emissions and chemical speciation of total organic gases (TOGs), including volatile organic compounds (VOCs), intermediate volatility organic compounds (IVOCs), CH4, and unidentified non-methane hydrocarbons (NMHCs) for assessing the formation of ozone and secondary organic aerosol (SOA). In this study, TOG and speciation emissions from 12 in-use light-duty gasoline vehicle (LDGV) exhausts, covering the ESs from China II to China V, were investigated on a chassis dynamometer under the Worldwide Harmonized Light-duty Test Cycle (WLTC) in China. The results showed that the most effectively controlled subgroup in TOG emissions from LDGVs was VOCs, followed by the unidentified NMHCs and IVOCs. The mass fraction of VOCs in TOGs also reduced from 61 ± 9% to 46 ± 18% while the IVOCs gently increased from 2 ± 0.4% to 8 ± 4% along with the more stringent ESs. For the VOC subsets, the removal efficiency of oxygenated VOCs (OVOCs) was lower than those of other VOC subsets in the ESs from China IV to V, suggesting the importance of OVOC emission controls for relatively new LDGVs. The IVOC emissions were mainly subject to the ESs, then driving cycles and fuel use. The formation potentials of ozone and SOA from LDGVs decreased separately 96% and 90% along with the restricted ESs from China II-III to China IV. The major contributor of SOA formation transformed from aromatics in the VOC subsets for China II-III vehicles to IVOCs for China IV/V vehicles, highlighting that IVOC emissions from LDGVs are also needed more attentions to control in future.

Impacts of the New Worldwide Light-Duty Test Procedure on Technology Effectiveness and China's Passenger Vehicle Fuel Consumption Regulations.

As a main measure to promote the development of China’s energy–saving and new energy vehicles, the Phase V fuel consumption regulation is dramatically different from the past four phases, especially in the test procedure, moving from the New European Driving Cycle (NEDC) to the worldwide harmonized light duty test cycle (WLTC) and corresponding test procedure (WLTP). The switch of test procedure will not only affect the effectiveness of technologies but also change the fuel consumption target of the industry. However, few studies have systematically investigated the impacts of the new WLTP on the Chinese market. This study establishes a “technology–vehicle–fleet” bottom–up framework to estimate the impacts of test procedure switching on technology effectiveness and regulation stringency. The results show that due to the WLTP being closer to the real driving condition and more stringent, almost all baseline vehicles in the WLTP have higher fuel consumption than that in the NEDC, and diesel vehicles are slightly more impacted than gasoline vehicles. In addition, the impacts are increased with the strengthening of electrification, where the fuel consumption of plug–in hybrid electric vehicles (PHEVs) and range-extended electric vehicles (REEVs) in the WLTP are about 6% higher than that in the NEDC. Engine technologies that gain higher effects in low load conditions, such as turbocharging and downsizing, fuel stratified injection (FSI), lean–burn, and variable valve timing (VVT), are faced with deterioration in the WLTP. Among these, the effect of turbocharging and downsizing shows a maximum decline of 8.5%. The variable compression ratio (VCR) and stoichiometric gasoline direct injection (SGDI) are among the few technologies that benefited from procedure switching, with an average improvement of 1.6% and 0.2% respectively. Except for multi–speed transmissions, which have improvement effects in the WLTP, all automatic transmissions are faced with decreases. From the perspective of the whole fleet and national regulation target, the average fuel consumption in the WLTP will increase by about 7.5% in 2025 compared to 4 L/100 km in the NEDC. According to the current planning of the Chinese government, the fuel consumption target of Phase V is set at 4.6 L/100 km in 2025, which is equivalent to loosening the stringency by 0.3 L/100 km. In Phase VI, the target of 3.2 L/100 km is maintained, which is 30.4% stricter than that of Phase V, and the annual compound tightening rate reaches 7.5%. This means that automakers need to launch their product planning as soon as possible and expand the technology bandwidth to comply with the Phase VI fuel consumption regulation, and the government should evaluate the technical feasibility before determining the evaluation methods and targets of the next phase.

Influence of Test Cycles on Energy Consumption Test of Electric Vehicles

In order to verify the necessity of the application of China Automotive Test Cycle which is constructed through actual driving data in china of more than 55 million kilometers in the energy consumption test of electric vehicles in China, this paper compares the characteristics of New European Test Cycle (NEDC), World-wide harmonized Light duty Test Cycle (WLTC) and China light-duty vehicle test cycle for passenger car(CLTC-P), and analyzes the differences of vehicle energy demand under different test cycles from theoretical and simulation point, simulation results show that the endurance mileage is longest and the energy recovery strategy is more effective under CLTC-P cycle. Finally, four types of vehicles are selected to carry out the endurance mileage test under these three test cycles. The test results are consistent with the simulation results. Therefore, in order to make the test results of electric vehicle energy consumption closer to the actual use of our country, CLTC-P should be selected to replace NEDC and WLTC cycle.

Experimental study on the energy consumption of gasoline engine lubricating pumps in standardized driving cycles

This paper aims to evaluate the potential of lubricating pumps to reduce the fuel consumption of passenger cars under the standardized driving cycles conditions. The transient parameters of lubricating pump in a gasoline engine are measured based on the test bench, and a quasi-steady-state model is brought forward to calculate the matching work state of lubricating pump and engine lubricating system. The result shows that a certain amount of excessive hydraulic power is needed under low speed condition to meet the step increase of lubricating requirement. In the range over piston spray cooling speed, the excessive hydraulic power of lubricating system is proportional to engine speed, and this part of driving power can be saved. The duration of acceleration conditions in driving cycles and the lubricant temperature are the most critical factors affecting the lubricating pump’s driving power. At 100 °C, the lunricating system driving energy costed in the Urban Driving Cycle (UDC) is 60.2% lower than 25 °C, but it is 42.1% in the World-wide harmonized Light duty Test Cycle (WLTC) due to the increase of acceleration condition. With a fully variable lubrication pump, the driving energy levels can reduce by 5.76%, 8.96%, 32.1% in WLTC, Extra-Urban Driving Cycle (EUDC), and UDC, respectively.

Numerical research on the performance, combustion and energy flow characteristics of gasoline-powered vehicle under WLTC

In order to evaluate and improve the performance of a vehicle equipped with a gasoline engine, an integrated model of the vehicle coupling with a detailed engine model was established to investigate the performance, combustion and energy distribution under the Worldwide Harmonized Light duty Test Cycle (WLTC) of cold start. The results show that 2.3–3.2 kW of brake power is required for the automatic transmission under idling conditions. Brake thermal efficiency mainly ranges from 17.71% to 31.94% apart from the rapid deceleration conditions and exhibits poor fuel economy under low-speed phase. Combustion phase of 50% mass fraction burnt (CA50) is usually delayed in case of knocking combustion under higher speed conditions. Moreover, it is delayed to 65 °CA at the initial stage of cold start for fast light-off of three-way catalyst (TWC), but 10–90% combustion duration (CA10-90) is not very sensitive to the cold start. The heat cumulated in the engine structure is obvious at the initial stage and up to 37.39% but finally occupies 4.93%. The proportion of heat transfer loss to coolant increases after 300 s and finally occupies 22.71%. Exhaust gas loss mainly ranges from 0.91 kW to 28.42 kW and its proportion first decreases and then increases to 26.46%. After 1160 s, it exhibits higher growth rate. Pumping loss varies from 0.1 kW to 2.67 kW and occupies 2.2% in the total energy. Furthermore, the findings in the paper can be applied to evaluate and optimize the energy distribution by changing different technologies or strategies in the future.

Optimal and prototype dimensioning of 48V P0+P4 hybrid drivetrains

This paper presents a virtual toolchain for the optimal concept and prototype dimensioning of 48 V hybrid drivetrains. First, this toolchain is used to dimension the drivetrain components for a 48 V P0+P4 hybrid which combines an electric machine in the belt drive of the internal combustion engine and a second electric machine at the rear axle. On an optimal concept level, the power and gear ratios of the electric components in the 48 V system are defined for the best fuel consumption and performance. In the second step, the optimal P0+P4 drivetrain is simulated with a prototype model using a realistic rule-based operating strategy to determine realistic behavior in legal cycles and customer operation. The optimal variant shows a fuel consumption reduction in the Worldwide harmonized Light Duty Test Cycle of 13.6 % compared to a conventional vehicle whereas the prototype simulation shows a relatively higher savings potential of 14.8 %. In the prototype simulation for customer operation, the 48 V hybrid drivetrain reduces the fuel consumption by up to 24.6 % in urban areas due to a high amount of launching and braking events. Extra-urban and highway areas show fuel reductions up to 11.6 % and 4.2 %, respectively due to higher vehicle speed and power requirements. The presented virtual toolchain can be used to combine optimal concept dimensioning with close to reality behaviour simulations to maximise realistic statements and minimize time effort.

Markov decision process of optimal energy management for plug-in hybrid electric vehicle and its solution via policy iteration

This paper proposes a Markov decision process based optimal energy management strategy for plug-in hybrid electric vehicle with a hybrid energy storage system, which mainly consists of an ultracapacitor, a power battery pack and a DC/DC converter. Firstly, the mathematical model is built for the overall system. Secondly, based on modified worldwide harmonized light duty test cycle, the power transition probability matrix is constructed to describe the Markov property of driver’s power demand in natural driving. Then by combining the stochastic property of driver’s power demand and deterministic state transition of the hybrid powertrain system, the energy management optimization problem is formulated into a typical Markov decision process. Finally, the derived optimization problem is solved by policy iteration and the corresponding optimal control map is generated. The optimality of the solution is investigated and discussed in detail.

Development of Kuala Lumpur driving cycle for the estimation of fuel consumption and vehicular emission

Driving cycles is a series of data points representing the speed of vehicle verses time sequence profile developed for certain road, route, specific area or city. Generally, driving cycle is used to estimate the fuel consumption (FC) and vehicular exhaust emission. The common factors that affected the FC and exhaust emission are the engine operating conditions such as cold start, low engine loads and high engine loads which are found during actual driving. The research presents the measurement and analysis of engine conditions based on actual driving behaviours in an attempt to formulate representative driving cycle for Kuala Lumpur. The methodology used for this research is adapted from the Worldwide Harmonized Light-duty Test Cycle (WLTC) introduced by the working party on pollution and energy (GRPE) under the United Nations Economic Commission for Europe (UNECE). This research covered a wide area of paved road in Kuala Lumpur, about 62.34% by surveying the road condition on the eight selected routes. The used of On-board Diagnostic (OBD) and Global Positioning System (GPS) equipment are used to record the vehicle travel speed during data collection activity. The driving characteristics are then analysed from speed profile and its target statistic parameters are defined to develop representative driving cycle. The characteristics of the newly developed driving cycle are compared to the European driving cycle which is currently being used in Malaysia for new vehicle certification and registration. Therefore, the correlation of FC is derived to indicate the impacts of real-world driving conditions relative to domestic conditions.

A cascaded energy management optimization method of multimode power-split hybrid electric vehicles

A novel multimode power-split hybrid electric vehicle demonstrates significant advantages in energy conservation. The complicated structure and multiple operation modes, however, have brought significant challenges to energy management. The problems of operation mode selection, power allocation, and operating point selection need to be solved simultaneously. Traditionally, existing energy management strategies first have determined operation mode and then have solved power allocation and operating points. Moreover, traditional dynamic programming usually has not considered electric energy consumption and has deviated from the optimal solution. To solve these problems, a cascaded energy management strategy that integrates dynamic programming and equivalent consumption minimization strategy (DP + ECMS) is proposed. An iterative method is used to optimize the equivalence factor. A vehicle model based on actual control strategy is established and validated by test results. Then fuel economy simulations are conducted. Results showed that DP + ECMS could achieve 19.9% fuel economy improvement compared with the rule-based strategy for a new European driving cycle. In addition, simulation results of a Worldwide Harmonized Light-Duty Test Cycle demonstrated that DP + ECMS performed well in real road driving conditions. This study introduces a novel multimode power-split hybrid system and provides a global energy management optimization method.

The High Potential for Waste Heat Recovery in Hybrid Vehicles: A Comparison Between the Potential in Conventional and Hybrid Powertrains

In future mobility, the mix of different drive trains will probably be much more diverse than it is today. According to a large number of scenario analyses, a predominant number of vehicles will continue to be based on the internal combustion engine (ICE), while an increasing number of hybrid vehicles are expected. To achieve the required reductions in CO2 emissions it is necessary to investigate all potential technologies for efficiency improvement. Therefore in this work the potential of waste heat recovery is examined for conventional and hybrid vehicles. Due to the fact that in an internal combustion engine approximately 2/3 of the fuel's chemical energy dissipates as waste heat, the potential for the recovery of this energy in all ICE driven powertrains is, in principle, high. The results of this work show that in hybrid vehicles the highest share of the energy supplied by the fuel is lost in the exhaust gas. In order to further elaborate this result, we conduct an exemplary examination of two comparable vehicles of the compact class within the worldwide harmonized light duty test cycle. Measurement data from the two vehicles at the roller dynamometer is used. The result shows that the averaged exhaust gas heat flow of the conventional vehicle is 5.0 kW. For the hybrid vehicle, driving in the charge sustaining mode, the averaged exhaust gas heat flow results in 8.1 kW. The comparison shows that the temperature level of this exhaust gas is even higher than that of the conventional vehicle. In addition, this work shows that through the higher temperatures, the exergy in the exhaust gas is higher in hybrid vehicles even if the combustion engine works with a higher efficiency. In the exemplary comparison the averaged exergy of the exhaust gas is 3.2 kW for the conventional and 5.7 kW for the hybrid vehicle. As a result of this work, the high potential for waste heat recovery in hybrid vehicles could be demonstrated.

Analysis of the impact of gasoline, biogas and biogas + hydrogen fuels on emissions and vehicle performance in the WLTC and NEDC

The use of gasoline fuel in passenger cars has become popular once again due to the pollutants (oxides of nitrogen and particulate matter) diesel engines emit. In addition, research and development have been going on regarding the use of alternative and environmental fuels, such as biogas and hydrogen fuel, in passenger cars. In this study, a numeric engine model that was empirically validated with the engine test was used. Then, the effects of biogas and biogas + hydrogen fuels on fuel consumption and emissions in the Worldwide Harmonized Light Duty Test Cycle and New European Driving Cycle were analysed. Based on the findings, it was concluded that positive results in terms of emissions and fuel consumption could be obtained with a low ratio of hydrogen (5% as molar) added to biogas fuel. With the addition of hydrogen, 16.3% increase in fuel consumption with the use of biogas alone decreased to 12.1% and the increase in CO emissions decreased from 21.6% to 11.7% during NEDC cycle.

The influence of multi-speed transmissions on electric vehicles energy consumption

The electric vehicle (EV) represents an important option in the process of road transport decarbonization. The limited driving range and high speed performances are obstacles for EV customer acceptance. While until now the emphasis for the improvement was on battery, power electronics and motor technologies, it becomes obvious that the transmission must be also addressed. The extensively used single-ratio transmission can satisfy the demands of city use, but do not attain other important functional needs that are ensured by conventional and hybrid electric vehicles. The aim of this paper is to analyse the energy consumption of an EV with multi-speed transmission in five test cycles among which Worldwide Harmonized Light duty Test Cycle (WLTC) is considered. This study is done by means of simulation using a model specifically developed in a simulation environment. In the interest of analysing the performances in several test cycles, one needs to compare global parameters such as: vehicle speed fluctuation (VSF), overall transmission efficiency, energy consumption ratio (ECR). A comparison between test cycles is made taking into consideration a relative parameter (ECR). The correlation between ECR and VSF is investigated as well. The results are also compared with those produced for a vehicle with diesel engine.