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Abstract Durability is one of the technical bottlenecks restricting fuel cell electric vehicle development. As a result, significant time and resources have been invested in research related to this area worldwide. Current durability research mainly focuses on the single cell and stack levels, which is quite different from the usage scenarios of actual vehicles. There is almost no research on developing durability test cycles on the fuel cell system level. This paper proposes a universal model for developing a durability test cycle for fuel cell system based on the China automotive test cycle. Large-scale comparison tests of the fuel cell systems are conducted. After 1000 h test, the output performance degradation of three mass-produced fuel cell system is 14.49%, 9.59%, and 4.21%, respectively. The test results show that the durability test cycle proposed in this paper can effectively accelerate the durability test of the fuel cell system and evaluate the durability performance of the fuel cell system. Moreover, the methodology proposed in this paper could be used in any other test cycles such as NEDC (New European Driving Cycle), WLTC (Worldwide Harmonized Light Vehicles Test Procedure), etc. And it has comprehensive application value and are significant for reducing the cost of durability testing of fuel cell systems and promoting the industrialization of fuel cell electric vehicles.

Durability is one of the technical bottlenecks restricting fuel cell electric vehicle development. As a result, significant time and resources have been invested in research related to this area worldwide. Current durability research mainly focuses on the single cell and stack levels, which is quite different from the usage scenarios of actual vehicles. There is almost no research on developing durability test cycles on the fuel cell system level. This paper proposes a universal model for developing a durability test cycle for fuel cell system based on the China automotive test cycle. Large-scale comparison tests of the fuel cell systems are conducted. After 1000 h test, the output performance degradation of three mass-produced fuel cell system is 14.49%, 9.59%, and 4.21%, respectively. The test results show that the durability test cycle proposed in this paper can effectively accelerate the durability test of the fuel cell system and evaluate the durability performance of the fuel cell system. Moreover, the methodology proposed in this paper could be used in any other test cycles such as NEDC (New European Driving Cycle), WLTC (Worldwide Harmonized Light Vehicles Test Procedure), etc. And it has comprehensive application value and are significant for reducing the cost of durability testing of fuel cell systems and promoting the industrialization of fuel cell electric vehicles. [ABSTRACT FROM AUTHOR]

The evaluation method of energy consumption and E-range of heavy-duty plug-in hybrid electric vehicle is mainly composed of test cycle, test procedure and calculation method of test result. At present, there are some problems in the national standard being implemented at present. Combined with the research results in the process of national standard revision, this paper comprehensively optimizes the evaluation method and carries out experimental verification. In terms of test cycle, the reasons for the application of China automotive test cycle are analyzed. In terms of test procedure, the deadline conditions of each test phase are analyzed, which makes the test more operable. In terms of calculation methods, based on UF, the method of each phase and comprehensive energy consumption, as well as energy consumption conversion, are analyzed. The test results show that, after the optimization of the evaluation method, the electricity consumption of the phase I increases by 78.99%, the fuel consumption of the phase III increases by 19.58%, and the E-range decreases by 39.06%. At the same time, the comprehensive energy consumption of the vehicle is obtained. After considering the conversion of electricity consumption, the fuel consumption increases significantly, among which, the simple conversion method increases the lowest, while the carbon dioxide emission conversion method increases the highest with an increase of nearly 51%.

In order to narrow the gap between real-road and certification test fuel consumption rate of heavy-duty commercial vehicles. CHTC (China Heavy-duty vehicle Test Cycle) series test cycles have been developed, and will replace C-WTVC (China-World Transient Vehicle Cycle) test cycle in the latest standard for fuel consumption rate measurement of heavy-duty commercial vehicle. Due to the change of test cycle, the fuel consumption limits standard should also be revised. In this paper, all kinds of the heavy-duty commercial vehicles have been chosen, and the fuel consumption rates under CHTC and C-WTVC have been measured. The fuel consumption values under idling, acceleration, deceleration and constant speed conditions were calculated after the treatment of same mileage. Also the fuel consumption rate under different conditions were compared in order to realize the reasons causing the fuel consumption rate variation. Results showed that the fuel consumption rate of CHTC were slightly lower than C-WTVC except for bus and coach. And the main reasons for the fuel consumption rate variation were attributed to the fuel consumption rate under constant speed condition and the accelerated condition. In addition, the driving efficiency of the two test cycles was another reason, that is, the difference of the duration of each condition under the same mileage. The longer the duration, the higher the fuel consumption.

The deteriorated condition of friction liners after prolonged use is one of the primary causes of judder in centrifugal clutches. The friction characteristics can be retained by generating specific textures or grooves on the friction liner. An attempt has been made to study the characteristics of centrifugal clutch using grooved friction liners. A test cycle for centrifugal clutch has been developed using a number of engagements as the basis. A vehicle test bench was used for the experiment where the developed test cycle was automated. The performance characteristics of the centrifugal clutch have been recorded and analyzed with normal friction liners and grooved friction liners for 100 test cycles. For this study, the groove area ratio was retained at 0.15, and the grooves were cut at 90°. After completing 100 test cycles, the clutch with a grooved friction liner exhibited better characteristics. After completing 100 test cycles, the surface roughness reduction at the leading section of the grooved friction liner and normal friction liner has been found to be 6.44% and 8.11%, respectively. The thickness reduction at the leading section of the grooved friction liner and normal friction liner has been reported to be 3.73% and 4.98%, respectively. Throughout the run of 100 test cycles, the higher clutch housing temperature has been witnessed in the case of a clutch with a grooved friction liner. At the 100th test cycle, the clutch torque with a grooved friction liner was 15.22% more than the clutch torque with a normal friction liner. Even after prolonged use, the clutch with grooved friction liner exhibited better judder characteristics and also provided higher fuel economy for vehicles. [ABSTRACT FROM AUTHOR]

Due to their critical influence on manufacturing accuracy, machine tool feed drives and the monitoring of their condition has been a research field of increasing interest for several years already. Accurate and reliable estimates of the current condition of the machine tool feed drive's components ball screw drive (BSD) and linear guide shoes (LGSs) are expected to significantly enhance the maintainability of machine tools, which finally leads to economic benefits and smoother production. Therefore, many authors performed extensive experiments with different sensor signals, features and components. Most of those experiments were performed on simplified test benches in order to gain genuine and distinct insights into the correlations between the recorded sensor signals and the investigated fault modes. However, in order to build the bridge between real use cases and scientific findings, those investigations have to be transferred and performed on a more complex test bench, which is close to machine tools in operation. In this paper, a condition monitoring test cycle is developed for such a test bench. The developed test cycle enables the recording of a re-producible data basis, on which models for the condition monitoring of BSDs and LGSs can be based upon. [ABSTRACT FROM AUTHOR]

A statistical analysis of multiyear laboratory test results of artillery tracers number 8 is presented in this article. This analysis was aimed at testing the impact of a natural ageing process on quality indicators during the long-time storage of these tracers. The influence of storage time on taking a diagnostic decision, relating to quality of lots after the conducted laboratory tests and on different classes of inconsistencies that occurred during these tests, was analysed. A detailed analysis of the impact of the storage time on diagnostic shooting decisions taken was also presented. The conducted statistical analysis suggests an assumption, that it is possible to change an evaluation module in the previous test’s methodology. Modification of this evaluation module will not negatively impact on the quality of further diagnostic tests. It will not negatively impact on correct evaluation of the prediction process of the tested elements of ammunition such as artillery tracers. The statistical analysis, carried out in the article, may have a significant impact on the modification of test methodology of the artillery tracers.

The present study deals with the development of a test cycle for the centrifugal clutch of continuously variable transmission (CVT) driven scooters. Centrifugal clutch experiences different duty cycles during the usage of scooters in city traffic and highways during its lifetime. Since the friction characteristics of the centrifugal clutch are controlled by acquired factors, it is difficult to predict ideal friction characteristics under all conditions. The wear of friction lining increases due to heat generated in the clutch assembly because of the repeated “stick-slip” phenomena. Therefore, an attempt has been made for developing à new test cycle by keeping the engagement frequency as a reference. Road load data for three different riding conditions have been collected and analyzed. The developed test cycle has been automated on the centrifugal clutch test bench and a new set of clutch liners was tested thoroughly. The surface roughness, thickness, and wear of clutch liners have been observed and evaluated against the field vehicles. For the surface roughness, maximum deviations of 3.74%, 3.36%, and 2.16% have been observed for trailing, middle and leading sections of clutch liners respectively. For the thickness, maximum deviations of 3.06%, 2.59%, and 3.14% have been observed for trailing, middle and leading sections of clutch liners respectively. The developed test cycle demonstrates a good correlation with field use.

This article briefly presents the testing processes of vehicle and engine testing on chassis and engine dynamometers in a laboratory environment and their development trend due to the stricter environmental regulations. It then explains the test cycles that form the basis of the measurements and their effect on emissions and components of the exhaust system. It briefly summarizes the potential processes of soot formation. It researches and describes the possibilities of reducing the duration and costs of testing and inspection processes in the field of particulate emissions of internal combustion engines.

Digital microfluidic biochip is a promising alternative to the traditional cumbersome laboratory equipment. Such automated biochips are used in many critical applications. Hence dependability is an essential attribute before the chip is in use. Due to mixed integration technologies, these chips have some unique failures. Hence robust offline and online tests are proposed to check the health of the biochips. When a chip undergoes a test in offline mode, then the entire biochip should be available for testing, whereas for the online mode test droplet might be stalled due to unavailability of the next cell in the routing path. However, in both the scenarios one or more droplets route across the chip and the arrival time is also recorded at the destination. So here we have proposed two test schemes to know the correctness of any biochip. Diagnosability is an important feature to find the exact position of the faulty electrode. Our proposed scheme reduces the overall testing and diagnosis time significantly. It also provides an alternative routing path in biochip for fault tolerance. [ABSTRACT FROM AUTHOR]

Highlights • Methodology can be applied to real-world energy consumption data. • Results indicate high correlation between direct fuel injection and energy efficiency. • Technologies' efficiency by vehicle mass were analysed and discussed. • Results from the proposed method match results from previous research. Abstract Even with the automotive technological evolution steadily improving energy efficiency, the transportation sector continues to account for more than one-fifth of greenhouse gas emissions (GHG). The official fuel consumption information has presented divergences in relation to the values found in real driving. Due to this variation, the effectiveness of technologies for the improvement of energy efficiency has been questioned. Aiming to verify these divergences, the aim of this study was to evaluate the relationship between embedded technologies intended to reduce fuel consumption and the official data on energy consumption. For the development of this method, the official on energy consumption of the light vehicles sold in Brazil were used. The innovative method developed in this study allowed the evaluation of consumption without the influence of vehicle weight, in a way to identify the best performing technologies. As a result, it was identified that technologies, such as the direct fuel injection (DFI) and electric power steering (EPS), presented positive correlation with fuel economy for all vehicle loads. The 3-cylinder engines showed favourable performance in vehicles up to 1200 kg, and 2.0-litre 4-cylinder engines had the best correlation coefficient of the evaluated fleet, with the best performance in models that were up to two tons. The boosted engines, with turbocharger or compressor, performed favourably across all vehicle sizes. Variable Valve Timing (VVT) also showed superiority in efficiency across all weight ranges, regardless of the number of valves per cylinder. The benefits of manual transmissions, with five and six speeds, stood out in vehicles up to 1200 kg and in the ones near two tons. The method used in this work demonstrated consistency by comparing fuel economy in other research. This study contributes to the activities of researchers, legislators, suppliers and vehicle manufacturers in the identification of the most recommended technologies for each vehicle size. [ABSTRACT FROM AUTHOR]

Exhaust gas emissions of combustion engines can be harmful to the environment, climate, and human health. Hence, emission limits have been increasingly reduced over the last few years, and new dynamic test cycles for test stands have been introduced. Recently, emission legislation was extended by adding testing procedures during real-world operations. The recording of so-called real driving emissions (RDE) with portable emission measurement systems (PEMS) is complex, especially for non-road applications, such as tractors. Emission-relevant sites and environmental conditions vary widely, and RDE measurements with PEMS are limited to an observation period of only a few hours. This paper presents a feasible methodology to determine exhaust emissions for specific tractor operations that are representative of longer periods. Based on long-term recorded GPS data, as well as engine control unit (ECU) speed and torque data from a tractor, six work-specific test cycles were developed and transferred to a tractor test stand. By comparing ECU data from test stand operations with ECU data recorded during field operations, the quality of the procedure was assessed. Emission measurements was conducted. Nitrogen oxides (NO X), carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM) and particulate number (PN) emissions for the tractor works considered with rapeseed oil (DIN 51605) and diesel fuel (CEC RF 06-03) were lower under real operation conditions than those when applying the legal non-road transient cycle (NRTC). The results show that using rapeseed oil fuel instead of diesel fuel offers a huge potential for reducing greenhouse gas emissions. Highlights • Six representative tractor test cycles are generated from 206 h of recorded ECU and GPS data. • Successful replication of the in-field recorded engine operation profiles on the tractor test stand. • Real work-based NO X , HC, CO and particle emissions are generally lower than those in legal-based test cycles. • Rapeseed oil fuel features a high potential for greenhouse gas reduction. [ABSTRACT FROM AUTHOR]

In this paper, the light duty that meets the China 6 emission standard is selected to study the emission characteristics of different emission control technology routes under China light-duty vehicle test cycle (CLTC). The results show that the cold start stage of CLTC cycle is still the stage with the most pollutant emissions. The THC, CO and NOx emissions of vehicles on the supercharged direct injection technology are higher than those on the naturally aspirated port fuel injection technology. In terms of reducing the exhaust emission, PHEV technology route is the best, followed by naturally aspirated PFI technology route, and then turbocharged direct injection with GPF route.

The water-soluble inorganic ions (WSII) in diesel particulate matter (DPM) have a significant impact on ambient air quality and human health. In this study, the 12 groups of bench tests were conducted to analyze the emission characteristics of two diesel engines, taking into account the influence of engine parameters, test cycle, fuel types, and after-treatment measures. Compared to conventional diesel, a blend of diesel with 5 % biodiesel resulted in a reduction of the WSII emission factors by 23.7–48.0 %. The emission factors of WSII decreased by 8.4 % after installing selective catalytic reduction (SCR). Dummy variable regression analysis was used to analyze the relationship between WSII and influencing factors. The emission factors of Na+, K+, and Ca2+ were mostly affected by the engine, potentially due to the use of coolants and lubricants containing metal oxides in the engine. The emission factors of NO 3 - were mainly affected by the test cycle. Techniques for order preference by similarity to ideal solution (TOPSIS) were used to analyze the priority of emission reduction technologies. The results indicated that SCR, biodiesel, and low-sulfur diesel could effectively reduce WSII. This study aims to explore the influence of multiple factors on WSII, providing valuable insights for future research on WSII in DPM. [Display omitted] • TOPSIS was utilized to analyze the priority of emission reduction technologies. • SO 4 2- emissions are affected by test cycles and sulfur content in the fuel. • The emissions of Na+, K+, and Ca2+ increased significantly by the thermal volatilization of reagents. • The correlation between NH 4 + and NO 2 - emission was significant (r = 0.627, p < 0.05). • F- emissions resulted from the application of fluorine in engines, which reduced total WSII emissions. [ABSTRACT FROM AUTHOR]

Higher speeds, faster acceleration and longer duration need a more realistic driving cycle. As a result, a new test procedure that reflects real-world driving conditions has been applied since 2017, and the previous development environment optimized for NEDC has also changed. In this study, several factors and technologies relating to fuel consumption, such as vehicle weight, tire rolling resistance, drag of aerodynamic, stop–start, and 48 V mild hybrid system, are evaluated as per the new worldwide harmonized light vehicles test procedure (WLTP) and compared with that of the previous European driving cycle (NEDC). The impact of the vehicle weight is increased in case of the WLTP due to faster acceleration compared to that under NEDC. The influence of aerodynamic force is very important as the average and maximum speed are increased. Meanwhile, the impact of idle stop–start technology is lower compared to that under NEDC due to the reduction in idle operation time. The 48-V mild hybrid system is still expected to play a role as a powerful fuel consumption reduction technology under new WLTP by applying energy regeneration, minor torque assist, and extended idle stop–start.

U.S. government fuel economy tests are used for two primary purposes: 1) to monitor automobile manufacturers’ compliance with fuel economy and greenhouse gas emissions standards and 2) to inform consumers about the fuel economy of passenger cars and light trucks. This study analyzes a unique database of 75,000 fuel economy estimates self-reported by customers of the U.S. government website www.fueleconomy.gov to evaluate the effectiveness of the government's estimates for these two purposes. The analysis shows great variability in individuals’ own fuel economy estimates relative to the official government estimates with a small bias relative to the sample average. For consumers, the primary limitation of government fuel economy estimates is imprecision for a given individual rather than bias relative to the average individual. The analysis also examines correlations between individuals’ fuel economy estimates and specific technologies, vehicle class, driving style, method used to calculate fuel economy, manufacturer, and state. Gasoline, hybrid and diesel vehicles were separately evaluated. There is some evidence that the shortfall between test cycle fuel economy estimates (used to measure compliance with regulations) and in-use fuel economy estimates (such as those provided by customers of www.fueleconomy.gov ) has been increasing since 2005. If this trend continues, it could affect the benefits realized by fuel economy and greenhouse gas emissions standards. A scientifically designed survey of in-use fuel economy is needed to insure that an unbiased sample is collected and that fuel economy is rigorously and consistently measured for all vehicles. The potential for information technology to enable more precise prediction of individual fuel economy should be explored. [ABSTRACT FROM AUTHOR]

In electric vehicles electric vacuum pumps are used instead of traditional vacuum generation devices - the vacuum pump or the intake manifold that are specific to vehicles with internal combustion engines. A special driving cycle has to be designed to identify the effectiveness of electric vacuum pumps. The initial experiments were carried out on a real road, intensively applying the breaks and exploiting the vacuum generation devices as long and intensively as possible. Basing on these experiments brake test cycle was developed. It consists of three braking regimes that involve smooth and uninterrupted braking, interrupted and repeated braking and multiple activation of the brake pedal. Using this cycle, it is possible to conduct research on the performance of various automobile components during braking. [ABSTRACT FROM AUTHOR]

In this study, dynamometer engine tests were conducted to investigate the impact of test cycle and fuel type on fuel consumption and exhaust emissions of a heavy-duty diesel engine. This study presented novel approaches by utilizing comprehensive statistical analysis to assess these impacts on particulate matter (PM), PM-bound polycyclic aromatic hydrocarbons (PAHs), and multiple gaseous pollutants. Four types of fuels—two conventional diesels (X and Y) and each with 5% blend of biodiesel—were used under European Transient Cycle (ETC) and European Stationary Cycle (ESC). There were statistically significant higher fuel consumption and emission rates (by 9–73%) under ETC than ESC due to more occurrences of lower engine speeds and loads under ESC, and X fuels had higher emission rates of PM and carbon dioxides ([CO 2 ]; 2.1–13%) but lower rates of hydrocarbons ([THC]; 44%) attributed to higher cetane number, sulfur contents and boiling points. Compared with conventional diesel, biodiesel blend had slightly lower emission rates of PM, CO, and NO X (1.7–6.6%) but higher fuel consumption (1%) and CO 2 and THC emission rates (0.9–2.1%). The results of this study contributed to the limited datasets on the interactive effects of test cycle with fuel property on diesel vehicle exhaust emissions. • Impacts of test cycle and fuel type on diesel engine emissions were investigated. • Test cycle, fuel, and their interaction explained >84% of variance in emissions. • PM, CO, and NOx emissions were slightly lower in biodiesel blend than fossil diesel. • Fuel consumption, PM and gas emissions were significantly higher under ETC than ESC. • Higher PAHs in fuels produced more heavy molecular weight PM-bound PAH emission. [ABSTRACT FROM AUTHOR]

Biodiesel and bio-ethanol are expected to be the most applied biofuels in Europe in the short- to mid-term, especially in blended form with diesel and gasoline, respectively. There is a clear need to see what impact this blending will have on emissions and fuel consumption of current vehicles. Public information on this topic is mostly based on older technology. Within the Belgian research project BIOSES, emission and fuel consumption tests were performed on recent types of vehicles running on various biodiesel–diesel blends for diesel vehicles, and bio-ethanol–gasoline blends for gasoline and flex-fuel vehicles. The vehicles were tested on a proving ground with on-board emission measurement equipment, following different test cycles, including the European test cycle (NEDC) and a real-traffic-based cycle (MOL30). The paper shows an overview and discussion of the test results. [ABSTRACT FROM AUTHOR]

A method for prediction of heavy heavy-duty diesel vehicle emissions on a test cycle using data from dissimilar test cycles is examined and presented. Four dissimilar modes of a new California test schedule were used to generate emission predictions for the US heavy-duty urban dynamometer driving schedule (UDDS). Intensive properties of each mode and of the UDDS, including average speed, stops/mile, percentage idle and average kinetic energy, were chosen for further study. The four dissimilar modes were the idle, creep, transient and cruise modes, created by the California Air Resources Board (CARB) in a prior effort. The predictive weightings were applied to emissions from 11 heavy-duty vehicles measured in units of grams/second (g/s), grams/litre of fuel consumed (g/l) and brake specific emissions (g/kW h). Predictions of emissions for the UDDS in units of grams/ second of NO[sub x] and CO[sub 2] were acceptable, but particulate matter (PM) deviations were substantial. Errors for prediction of NO[sub x] did not exceed 7 per cent for any case, and errors for CO[sub 2] prediction did not exceed 15 per cent. PM errors in the g/s case varied substantially, depending on the weighting case, indicating instabilities in the predictions. Errors for g/l and g/kW h predictions were higher. A series of corrections was applied to each of the predictive cases for each emissions unit studied. These corrections are shown to improve the predictive ability of the weightings, but the fundamental nature of the prediction was eroded. A weighting using the intensive properties of average speed, percentage idle and average kinetic energy was found to yield the best uncorrected prediction for every case, regardless of the emissions unit considered. The best predictive method was also shown to work acceptably when applied to unseen data from another 12 heavy-duty vehicles. [ABSTRACT FROM AUTHOR]

Higher speeds, faster acceleration and longer duration need a more realistic driving cycle. As a result, a new test procedure that reflects real-world driving conditions has been applied since 2017, and the previous development environment optimized for NEDC has also changed. In this study, several factors and technologies relating to fuel consumption, such as vehicle weight, tire rolling resistance, drag of aerodynamic, stop–start, and 48 V mild hybrid system, are evaluated as per the new worldwide harmonized light vehicles test procedure (WLTP) and compared with that of the previous European driving cycle (NEDC). The impact of the vehicle weight is increased in case of the WLTP due to faster acceleration compared to that under NEDC. The influence of aerodynamic force is very important as the average and maximum speed are increased. Meanwhile, the impact of idle stop–start technology is lower compared to that under NEDC due to the reduction in idle operation time. The 48-V mild hybrid system is still expected to play a role as a powerful fuel consumption reduction technology under new WLTP by applying energy regeneration, minor torque assist, and extended idle stop–start. [ABSTRACT FROM AUTHOR]