scholarly journals Performance verification of heavy-duty motorcycles adjusting intake and exhaust timing

2021 ◽  
Vol 2141 (1) ◽  
pp. 012007
Author(s):  
Zih-Chun Dai
Keyword(s):  
Environmental Protection ◽  
Power Output ◽  
Exhaust Pipe ◽  
Heavy Duty ◽  
Performance Verification ◽  
Improve Efficiency ◽  
Fuel Ratio ◽  
Speed Performance ◽  
And Performance ◽  
The Sacrifice

Abstract Heavy-duty locomotives with large exhaust vehicles have become a common means of transportation for Taiwanese. However, for car owners to increase power output, improve efficiency, and reduce fuel use, the original factory has designed demand settings for cost, environmental protection, and regulations. This leads to the sacrifice of the performance of the original car design, so the RC2 Super ECU is used to replace the original injection computer, and the air-fuel ratio, ignition angle and exhaust pipe are modified. Without the need to change the structure of the heavy locomotive, the horsepower of the heavy locomotive is improved. It is pointed out that the modification of these three original factory settings has greatly improved the overall speed performance of the heavy-duty locomotive horsepower. Therefore, it is proposed that “heavy locomotive performance verification by changing the timing of intake and exhaust” is mainly to verify the performance benefits and performance brought about by modifying the air-fuel ratio, ignition angle and exhaust pipe.

Optimum Design and Performance Simulation of a Multi-device Integrated System Based on a Proton Exchange Membrane Fuel Cell

2022 ◽  
pp. 1-33
Author(s):  
Xiuqin Zhang ◽  
Wentao Cheng ◽  
Qiubao Lin ◽  
Longquan Wu ◽  
Junyi Wang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Power Output ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Proton Exchange ◽  
Integrated System ◽  
Interior Space ◽  
And Performance ◽  
Exchange Membrane

Abstract Proton exchange membrane fuel cells (PEMFCs) based on syngas are a promising technology for electric vehicle applications. To increase the fuel conversion efficiency, the low-temperature waste heat from the PEMFC is absorbed by a refrigerator. The absorption refrigerator provides cool air for the interior space of the vehicle. Between finishing the steam reforming reaction and flowing into the fuel cell, the gases release heat continuously. A Brayton engine is introduced to absorb heat and provide a useful power output. A novel thermodynamic model of the integrated system of the PEMFC, refrigerator, and Brayton engine is established. Expressions for the power output and efficiency of the integrated system are derived. The effects of some key parameters are discussed in detail to attain optimum performance of the integrated system. The simulation results show that when the syngas consumption rate is 4.0 × 10−5 mol s−1cm−2, the integrated system operates in an optimum state, and the product of the efficiency and power density reaches a maximum. In this case, the efficiency and power density of the integrated system are 0.28 and 0.96 J s−1 cm−2, respectively, which are 46% higher than those of a PEMFC.

EFFECT OF REACTION TRAINING ON DURATION AND REACTION TIMES

2021 ◽  
Vol 7 (27) ◽  
pp. 86-92
Author(s):  
Tülin ATAN
Keyword(s):  
Reaction Time ◽  
Normal Distribution ◽  
Training Program ◽  
Reaction Times ◽  
Rank Test ◽  
Tennis Players ◽  
Before And After ◽  
Speed Performance ◽  
And Performance ◽  
Training Exercises

In this study, it was aimed to examine the effects of reaction training on reaction time and speed in tennis players. For this purpose a total of 18 tennis players; 9 male (age; 13.33 ± 1.80 years) and 7 female (13.85 ± 2.19 years) were voluntarily participated the study. In this study, the reaction training program, which was applied for 2 days a week for 12 weeks, was prepared in addition to tennis training. In the reaction training, exercises suitable for visual and auditory reaction were used. Before and after the 12-week reaction training, a 30 m speed running test and reaction time tests were performed. Whether the data showed normal distribution was analyzed with the Shapiro Wilk test and it was determined that the data did not show normal distribution. Mann Whitney U test was used in comparisons between the two groups. Wilcoxan Signd Rank test was used in the comparisons made before and after the training. As a result of the statistical analysis, it was seen that both the physical characteristics and performance parameters of males and females in our study group were not statistically different (p>0.05). For this reason, all subjects were taken into consideration regardless of gender in comparisons before and after tennis training. After the reaction training program applied to the subjects, it was determined that the 30 m speed performance values were shortened in duration compared to the pre-training period, that is, the speed improved (p <0.01). When the reaction time values were compared before and after the training program applied, it was seen that the reaction time values improved significantly after the training (p <0.01). As a result, reaction training performed in tennis players’ increases speed and reaction time performance. Reaction training is recommended in sports branches where this type of motor is important.

Physical Demands and Performance Indicators in Male Professional Cyclists During a Grand Tour: WorldTour Versus ProTeam Category

2021 ◽  
pp. 1-9
Author(s):  
Xabier Muriel ◽  
Pedro L. Valenzuela ◽  
Manuel Mateo-March ◽  
Jesús G. Pallarés ◽  
Alejandro Lucia ◽  
...  
Keyword(s):  
Power Output ◽  
Performance Indicators ◽  
Cycling Performance ◽  
Threshold Power ◽  
Grand Tour ◽  
Physical Demands ◽  
Physical Demand ◽  
Stress Score ◽  
And Performance ◽  
Training Stress

Purpose: To compare the physical demands and performance indicators of male professional cyclists of 2 different categories (Union Cycliste Internationale WorldTour [WT] and ProTeam [PT]) during a cycling grand tour. Methods: A WT team (n = 8, 31.4 [5.4] y) and a PT team (n = 7, 26.9 [3.3] y) that completed “La Vuelta 2020” volunteered to participate. Participants’ power output (PO) was registered, and measures of physical demand and physiological performance (kilojoules spent, training stress score, time spent at different PO bands/zones, and mean maximal PO [MMP] for different exertion durations) were computed. Results: WT achieved a higher final individual position than PT (31 [interquartile range = 33] vs 71 [59], P = .004). WT cyclists showed higher mean PO and kilojoule values than their PT peers and spent more time at high-intensity PO values (>5.25 W·kg−1) and zones (91%–120% of individualized functional threshold power) (Ps < .05). Although no differences were found for MMP values in the overall analysis (P > .05), subanalyses revealed that the between-groups gap increased through the race, with WT cyclists reaching higher MMP values for ≥5-minute efforts in the second and third weeks (Ps < .05). Conclusions: Despite the multifactorial nature of cycling performance, WT cyclists spend more time at high intensities and show higher kilojoules and mean PO than their PT referents during a grand tour. Although the highest MMP values attained during the whole race might not differentiate between WT and PT cyclists, the former achieve higher MMP values as the race progresses.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

scholarly journals Influence of COVID-19 Restrictions on Training and Physiological Characteristics in U23 Elite Cyclists

2021 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Peter Leo ◽  
Iñigo Mujika ◽  
Justin Lawley
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Training Load ◽  
Peak Power Output ◽  
Physiological Performance ◽  
Performance Variables ◽  
Elite Level ◽  
And Performance ◽  
Power Outputs ◽  
Elite Cyclists

PURPOSE: The COVID-19 pandemic and its associated mobility restrictions caused many athletes to adjust or reduce their usual training load. The aim of this study was to investigate how the COVID-19 restrictions affected training and performance physiology measures in U23 elite cyclists. METHODS: Twelve U23 elite cyclists (n = 12) participated in this study (mean ± SD: Age 21.2 ± 1.2 years; height 182.9 ± 4.7 cm; body mass 71.4 ± 6.5 kg). Training characteristics were assessed between 30 days pre, during, and post COVID-19 restrictions, respectively. The physiological assessment in the laboratory was 30 days pre and post COVID-19 restrictions and included maximum oxygen uptake (V̇O2max), peak power output for sprint (SprintPmax), and ramp incremental graded exercise (GXTPmax), as well as power output at ventilatory threshold (VT) and respiratory compensation point (RCP). RESULTS: Training load characteristics before, during, and after the lockdown remained statistically unchanged (p > 0.05) despite large effects (>0.8) with mean reductions of 4.7 to 25.0% during COVID-19 restrictions. There were no significant differences in maximal and submaximal power outputs, as well as relative and absolute V̇O2max between pre and post COVID-19 restrictions (p > 0.05) with small to moderate effects. DISCUSSION: These results indicate that COVID-19 restrictions did not negatively affect training characteristics and physiological performance measures in U23 elite cyclists for a period of <30 days. In contrast with recent reports on professional cyclists and other elite level athletes, these findings reveal that as long as athletes are able to maintain and/or slightly adapt their training routine, physiological performance variables remain stable.

scholarly journals Physiological Responses and Predictors of Performance in a Simulated Competitive Ski Mountaineering Race

2021 ◽  
pp. 250-257
Author(s):  
Michael Lasshofer ◽  
John Seifert ◽  
Anna-Maria Wörndle ◽  
Thomas Stöggl
Keyword(s):  
Laboratory Test ◽  
Power Output ◽  
Ventilatory Threshold ◽  
Elite Athletes ◽  
Physiological Responses ◽  
Performance Parameters ◽  
Ramp Test ◽  
The Past ◽  
Treadmill Speed ◽  
And Performance

Competitive ski mountaineering (SKIMO) has achieved great popularity within the past years. However, knowledge about the predictors of performance and physiological response to SKIMO racing is limited. Therefore, 21 male SKIMO athletes split into two performance groups (elite: VO2max 71.2 ± 6.8 ml· min-1· kg-1 vs. sub-elite: 62.5 ± 4.7 ml· min-1· kg-1) were tested and analysed during a vertical SKIMO race simulation (523 m elevation gain) and in a laboratory SKIMO specific ramp test. In both cases, oxygen consumption (VO2), heart rate (HR), blood lactate and cycle characteristics were measured. During the race simulation, the elite athletes were approximately 5 min faster compared with the sub-elite (27:15 ± 1:16 min; 32:31 ± 2:13 min; p < 0.001). VO2 was higher for elite athletes during the race simulation (p = 0.046) and in the laboratory test at ventilatory threshold 2 (p = 0.005) and at maximum VO2 (p = 0.003). Laboratory maximum power output is displayed as treadmill speed and was higher for elite than sub-elite athletes (7.4 ± 0.3 km h-1; 6.6 ± 0.3 km h-1; p < 0.001). Lactate values were higher in the laboratory maximum ramp test than in the race simulation (p < 0.001). Pearson’s correlation coefficient between race time and performance parameters was highest for velocity and VO2 related parameters during the laboratory test (r > 0.6). Elite athletes showed their superiority in the race simulation as well as during the maximum ramp test. While HR analysis revealed a similar strain to both cohorts in both tests, the superiority can be explainable by higher VO2 and power output. To further push the performance of SKIMO athletes, the development of named factors like power output at maximum and ventilatory threshold 2 seems crucial.

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