Improving Fuel Economy Estimates on a Chassis Dynamometer Using Air Conditioner Correction Factors

Author(s):  
Jose Alejandro M. Reyes ◽  
Edwin N. Quiros

Abstract Carmakers, regulatory agencies, and consumers share an interest in accurately determining a vehicle’s fuel efficiency under operating conditions that match the expected use. Previous studies have shown that a vehicle’s air conditioning (A/C) system is the most energy-intensive non-propulsive system and significantly reduces fuel economy. This study aims to design and validate a new method of improving fuel economy estimates obtained on non-climate-controlled chassis dynamometers, as such laboratories are limited to measuring fuel economy with the A/C system deactivated. The methodology proposed herein uses a chassis dynamometer to measure the fuel economy penalty caused by the A/C system at different steady-state conditions. The hypothesis is that these penalties can be imposed accordingly for a given drive cycle to obtain an additional fuel consumption due to A/C. To validate the proposed methodology, a vehicle was outfitted with a data acquisition system and was driven 50 times around a predefined route using varying A/C settings. The proposed method was then used to estimate the additional fuel consumption due to A/C usage for each of the runs. Comparing the calculated and actual fuel economies showed an average error of 1.924%. It was concluded that the proposed methodology is a viable alternative to existing procedures.

2021 ◽  
Vol 1 (50) ◽  
pp. 198-209
Author(s):  
Sakhno V ◽  
◽  
Dykich O ◽  

The article considers the issue of choosing a gearbox for the modernization of the BTR-70 by replacing two gasoline engines with two diesels. The object of research is the fuel economy of the BTR-70 car with different gearboxes when replacing two gasoline engines with two diesels. The purpose of the work – to determine the type and gear ratio of the transmission, which provides the best fuel efficiency of the car. Research method - mathematical modeling. When replacing a gasoline engine with a diesel of a different power and a different speed range, it is necessary to determine the gear ratio so as to provide the car with the required level of speed properties in the specified operating conditions with minimal fuel consumption. Due to the fact that the modernization of the BTR-70 involves the replacement of the engine and transmission, the further search for the gearbox was carried out on the basis of analysis of existing structures by the maximum torque of the engine. A five-speed and eight-speed MAZ gearbox and a six-speed Mercedes-Benz G 85-6 / 6.7 gearbox were used for analysis. Taking into account the fact that at a given coefficient of drag  = 0.03 the car can move only in direct gear, then for all gearboxes the fuel characteristics of steady motion will be the same as the control fuel consumption, which was 30 l / 100 km. In terms of fuel consumption during the acceleration of the car and the average kilometer fuel consumption when driving on paved roads, preference should be given to a car with a Mercedes-Benz G 85-6 / 6,7 transmission and only when driving in difficult road conditions, preference should be given to the car with 8-speed MAZ-5335 transmission. KEY WORDS: CAR, ENGINE, FUEL ECONOMY, TRANSMISSION, GEAR RATING, SPEED, COMPARATIVE EVALUATION


Author(s):  
Peter Vasquez ◽  
Edwin Quiros ◽  
Gerald Jo Denoga ◽  
Robert Michael Corpus ◽  
Robert James Lomotan

Abstract Efforts to mitigate climate change include lowering of greenhouse gas emissions by reducing fuel consumption in the transport sector. Various vehicle technologies and interventions for better fuel economy eventually require chassis dynamometer testing using drive cycles for validation. As such, the methodology to generate these drive cycles from on-road data should produce drive cycles that closely represent actual on-road driving from the fuel economy standpoint. This study presents a comparison of the fuel economy measured from a drive cycle developed using road load energy as a major assessment criterion and the actual on-road fuel economy of a 2013 Isuzu Crosswind utility vehicle used in the UV Express transport fleet in Metro Manila, Philippines. In this approach to drive cycle construction from on-road data, the ratio of the total road load energy of the generated drive cycle to that of the on-road trip is made the same ratio as their respective durations. On-road velocity and fuel consumption were recorded as the test vehicle traversed the 42.5 km. Sucat to Lawton route and vice versa in Metro Manila. Gathered data were processed to generate drive cycles using the modified Markov Chain approach. Three drive cycles of decreasing duration, based on the practicality of testing on a chassis dynamometer, were generated using three arbitrary data compression ratios. These drive cycles were tested using the same vehicle on the chassis dynamometer and compared with the on-road data using road load energy, fuel economy, average speed, and maximum acceleration. For the 893-seconds drive cycle generated, the road load energy error was 3.93% and fuel economy difference of 1.14%. For the 774-seconds cycle generated, the road load energy error was 4.34% and fuel economy difference was 0.91%. For the 664-seconds drive cycle, the road load energy error was 3.68% and fuel economy difference was 0.91%. On-road fuel economy for the 42.5-km. route averaged over nine round trips was 8.785 km/L. Based on the results, the road load energy criterion approach of drive cycle construction methodology can generate drive cycles which can very closely estimate on-road fuel economy.


2018 ◽  
Vol 8 (12) ◽  
pp. 2390 ◽  
Author(s):  
Jaehyuk Lim ◽  
Yumin Lee ◽  
Kiho Kim ◽  
Jinwook Lee

The five-driving test mode is vehicle driving cycles made by the Environment Protection Association (EPA) in the United States of America (U.S.A.) to fully reflect actual driving environments. Recently, fuel consumption value calculated from the adjusted fuel consumption formula has been more effective in reducing the difference from that experienced in real-world driving conditions, than the official fuel efficiency equation used in the past that only considered the driving environment included in FTP and HWFET cycles. There are many factors that bring about divergence between official fuel consumption and that experienced by drivers, such as driving pattern behavior, accumulated mileage, driving environment, and traffic conditions. In this study, we focused on the factor of causing change of fuel efficiency value, calculated according to how many environmental conditions that appear on the real-road are considered, in producing the fuel consumption formula, and that of the vehicle’s accumulated mileage in a 2.0 L gasoline-fueled vehicle. So, the goals of this research are divided into four major areas to investigate divergence in fuel efficiency obtained from different equations, and what factors and how much CO2 and CO emissions that are closely correlated to fuel efficiency change, depending on the cumulative mileage of the vehicle. First, the fuel consumption value calculated from the non-adjusted formula, was compared with that calculated from the corrected fuel consumption formula. Also, how much CO2 concentration levels change as measured during each of the three driving cycles was analyzed as the vehicle ages. In addition, since the US06 driving cycle is divided into city mode and highway mode, how much CO2 and CO production levels change as the engine ages during acceleration periods in each mode was investigated. Finally, the empirical formula was constructed using fuel economy values obtained when the test vehicle reached 6500 km, 15,000 km, and 30,000 km cumulative mileage, to predict how much fuel consumption of city and highway would worsen, when mileage of the vehicle is increased further. When cumulative mileage values set in this study were reached, experiments were performed by placing the vehicle on a chassis dynamometer, in compliance with the carbon balance method. A key result of this study is that fuel economy is affected by various fuel consumption formula, as well as by aging of the engine. In particular, with aging aspects, the effect of an aging engine on fuel efficiency is insignificant, depending on the load and driving situation.


2013 ◽  
Vol 712-715 ◽  
pp. 2173-2178
Author(s):  
Ping Sun ◽  
Xiu Min Yu ◽  
Wei Dong ◽  
Ling He

Hybrid electric vehicle (HEV) is integrated with the engine, the motor and the battery and so on. HEV has a significantly better fuel efficiency compared with conventional vehicles due to its multiple power sources. To evaluate fuel economy, HEV and its subsystem modeling methodologies were provided through the analysis of energy flow. The Equivalent Consumption Minimization Strategy (ECMS) was built based on the prototype. The ECMS implementation analytical formulation was developed. The equivalency factor, one for charging and the other for discharging, each of them was different during a driving cycle. In a certain drive, only a subset of them generates a trend close to zero, which indicates charge-sustainability.


Author(s):  
Denver Tolliver ◽  
Pan Lu

Fuel efficiency is an important consideration in evaluating public-sector investments in multimodal corridors. Two approaches are typically used in corridor studies to forecast railroad diesel fuel consumption: (1) system-average efficiency factors, and (2) detailed analytical estimates derived from train performance calculators. The former method is easy to apply but may not be reflective of the actual mix of trains used. The second method is data- and time-intensive and can only be effectively implemented with specialized software that is not publicly available. An intermediate method is introduced in this paper which allows distinctions among the types of trains that might be utilized in a corridor (e.g., unit, way, and through). A model is estimated from publicly available data that has excellent statistical properties and quantifies the absolute and relative fuel efficiencies of train options. The analysis demonstrates that using system-average fuel consumption factors may significantly understate railroad fuel economy when traffic moves in unit trains instead of mixed train service. The new method offers greater accuracy than system-average comparisons yet is much less data-intensive than train performance calculators or analytical methods.


2018 ◽  
Vol 20 (6) ◽  
pp. 640-652 ◽  
Author(s):  
Jose Manuel Luján ◽  
Carlos Guardiola ◽  
Benjamín Pla ◽  
Alberto Reig

This work studies the effect and performance of an optimal control strategy on engine fuel efficiency and pollutant emissions. An accurate mean value control-oriented engine model has been developed and experimental validation on a wide range of operating conditions was carried out. A direct optimization method based on Euler’s collocation scheme is used in combination with the above model in order to address the optimal control of the engine. This optimization method provides the optimal trajectories of engine controls (fueling rate, exhaust gas recirculation valve position, variable turbine geometry position and start of injection) to reproduce a predefined route (speed trajectory including variable road grade), minimizing fuel consumption with limited [Formula: see text] emissions and a low soot stamp. This optimization procedure is performed for a set of different [Formula: see text] emission limits in order to analyze the trade-off between optimal fuel consumption and minimum emissions. Optimal control strategies are validated in an engine test bench and compared against engine factory calibration. Experimental results show that significant improvements in both fuel efficiency and emissions reduction can be achieved with optimal control strategy. Fuel savings at about 4% and less than half of the factory [Formula: see text] emissions were measured in the actual engine, while soot generation was still low. Experimental results and optimal control trajectories are thoroughly analyzed, identifying the different strategies that allowed those performance improvements.


2014 ◽  
Author(s):  
M. Averbukh ◽  
A. Kuperman ◽  
G. Geula ◽  
S. Gadelovitch ◽  
V. Yuhimenko

Diesel generator based auxiliary power units (DG-APU) are widely used in different civil and military applications. Fuel economy and service life are probably the most important issues concerning their operation. Controlling engine throttle position in accordance with the load power allows regulating fuel supply to the engine to optimize fuel consumption. Despite the advantage of the method, control stability is sacrificed in case of light load operation as follows. When the DG-APU is running with a light load, engine throttle position should be nearly closed in order to minimize fuel consumption. If a load step is applied in such situation, engine velocity may drop sharply until complete stop because of insufficient control system bandwidth. This is why velocity and throttle position of a DG-APU should not be decreased below some level even if load power is low to maintain reliability at the expense of increased specific fuel consumption. Moreover, for small diesel-generators the throttle position is usually fixed. Thereby, relatively wide range load power variations (typical for many of diesel-generator applications) cause excessive fuel consumption. The situation may be sufficiently improved by connecting ultracapacitors (UC) on the DG-APU output terminals, introducing additional inertia allowing smoothing engine velocity decrease during a sudden load increase thus providing more time to the control system to regulate throttle position. As a result, DG-APU would be operated much more efficiently at light loads without sacrificing stability. Moreover, the UC may be used at as starter motor power source, removing starting stress from electrochemical batteries. Present work investigates the improvements in UC-supported DG-APU fuel efficiency and stability compared to conventional technical solutions. The research is based on mathematical modeling of the entire system, verified by experiments. The results support the presented ideas and quantitatively demonstrate the improved fuel economy and reliability of small DG-APUs.


2019 ◽  
Vol 9 (18) ◽  
pp. 3898 ◽  
Author(s):  
Jin Woong Lee ◽  
Su Chul Kim ◽  
Jooseon Oh ◽  
Woo-Jin Chung ◽  
Hyun-Woo Han ◽  
...  

This study was conducted to develop a load-sensitive engine speed control system to maximize the fuel efficiency of an agricultural tractor. The engine speed controller was developed through a model-based design approach using a tractor simulation model. The simulated engine speed and torque values were measured with an average error range of 1.4–4.9% compared to results obtained from field experiments. Using the tractor model, the gain parameters of the proportional–integral (PI) controller were optimized under the step, ramp, and actual load conditions. The simulation results using the actual load showed that the engine speed could be adjusted to within 2–3% of the desired value using the proposed engine speed controller. The throttle control system was constructed using four parts of a tractor engine, a microprocessor with an engine speed control algorithm, a throttle actuator, and a data acquisition system. Using the developed system, the operating engine speed values showed an average 1.17 % error compared to the desired engine speed. Three fuel efficiency parameters were used for evaluating the fuel-saving performance of the control system: specific volumetric fuel consumption (SVFC), fuel consumption per tilled area (FCA), and fuel consumption per work hour (FC). The values for SVFC, FCA, and FC obtained from the engine speed control system during plowing operations were 23.03–57.87%, 4.11–42.06%, and −7.24–38.48%, respectively, showing an improvement over the same operations without the control system.


2013 ◽  
Vol 718-720 ◽  
pp. 1825-1830
Author(s):  
Kong Jian Qin ◽  
Chang Yuan Wang ◽  
Jia Yan ◽  
Xue Hao Liu

Refuse truck accounted for 70% of the sanitation vehicle, which was the major heavy duty vehicle type in city. Therefore its fuel economy and emission characteristics were under higher requirements. This research did the emission test on the chassis dynamometer by using compressed truck, testing C-WTCV and CCBC circle emission, and fuel consumption respectively. The research showed the Km fuel consumption of CCBC circle was about 1.3 times of the C-WTVC from the analysis of fuel consumption and the emission of CO2.From the analysis of emission factor, the emission of NOX and CO of the CCBC circle was both higher than the C-WTVC, respectively 1.9 times and 1.4 times. However, the emission of HC was only 36% of the C-WTVC. C-WTVC was very similar to the motor of the CCBC circle in city, however the motorway cycle and emission both had significant difference from CCBC circle.


Author(s):  
Cheolwoong Park ◽  
Seungmook Oh ◽  
Taeyoung Kim ◽  
Heechang Oh ◽  
Choongsik Bae

Today, we are faced with the problems of global warming and fossil fuel depletion, and they have led to the enforcement of new emissions regulations. Direct-injection spark-ignition engines are a very promising technology that can comply with the new regulations. These engines offer the advantages of better fuel economy and lower emissions than conventional port-injection engines. The use of LPG as the fuel reduces carbon emissions because of its vaporization characteristics and the fact that it has lower carbon content than gasoline. An experimental study was carried out to investigate the combustion process and emission characteristics of a 2-liter spray-guided LPG direct-injection engine under lean operating conditions. The engine was operated at a constant speed of 2000 rpm under 0.2-MPa brake mean effective pressure, which corresponds to a common operation point of a passenger vehicle. Combustion stability, which is the most important component of engine performance, is closely related to the operation strategy and it significantly influences the degree of fuel consumption reduction. In order to achieve stable combustion with a stratified LPG mixture, an inter-injection spark ignition (ISI) strategy, which is an alternative control strategy to two-stage injection, was employed. The effects of the compression ratio on fuel economy were also assessed; due to the characteristics of the stratified LPG mixture, the fuel consumption did not reduce when the compression ratio was increased.


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