Browse Topic: Taxi fleets

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UAE previews autonomous future at DriftX24AUTP06_086/1/2024
Publicly available autonomous vehicles have been operating in Abu Dhabi since 2021, providing over 16,000 rides covering more than 300,000 km (186,400 miles). If the organizers and supporters of the inaugural DriftX conference have their way, these numbers will soon be dwarfed by autonomous vehicles of all types moving people and goods across the UAE and the wider MENA region. So far, all of these autonomous trips have been provided by the eight free, app-hailable AVs that are currently roaming around Yas and Saadiyat Islands. Motorsport fans will recognize Yas Island as the location of the Yas Marina Circuit used by Formula 1 and other racing events. The weekend after DriftX, for example, the Abu Dhabi Autonomous Racing League held its inaugural event there. It's all part of an intense governmental push to turn the Emirates into a global leader in AVs.
Blanco, Sebastian
Coordinated Charging and Dispatching for Large-Scale Electric Taxi Fleets Based on Bi-Level Spatiotemporal Optimization2024-01-28804/9/2024
The operation management of electric Taxi fleets requires cooperative optimization of Charging and Dispatching. The challenge is to make real-time decisions about which is the optimal charging station or passenger for each vehicle in the fleet. With the rapid advancement of Vehicle Internet of Things (VIOT) technologies, the aforementioned challenge can be readily addressed by leveraging big data analytics and machine learning algorithms, thereby contributing to smarter transportation systems. This study focuses on optimizing real-time decision-making for charging and dispatching in large-scale electric taxi fleets to improve their long-term benefits. To achieve this goal, a spatiotemporal decision framework using Bi-level optimization is proposed. Initially, a deep reinforcement learning-based model is built to estimate the value of charging and order dispatching under uncertainty. The model considers the long-term costs and benefits of different tasks and guides whether electric taxis should prioritize charging or order dispatching for the fleet's long-term benefits. Subsequently, a combinatorial optimization approach is employed to determine the specific targets for charging or order dispatching. Case studies are conducted within real-world operation data from electric taxis in Hangzhou City, China. The results validate the efficacy of the proposed method, as compared to a baseline approach. Across various fleet sizes and charging power conditions, the method significantly reduces non-service time during the charging process by optimizing charging time and location. The proposed method is found to be suitable for large-scale fleets and high-charging power scenarios.
Lyu, Yelin, Wang, Ning, Tian, Hangqi
Economic Competitiveness of Battery Electric Vehicles vs Internal Combustion Engine Vehicles in India: A Case Study for Two- and Four-Wheelers13-05-02-00144/4/2024
Abstract The initial cost of battery electric vehicles (BEVs) is higher than internal combustion engine-powered vehicles (ICEVs) due to expensive batteries. Various factors affect the total cost of ownership of a vehicle. In India, consumers are concerned with a vehicle’s initial purchase cost and prefer owning an economical vehicle. The higher cost and shorter range of BEVs compared to ICEVs severely limit their penetration in the Indian market. However, government subsidies and incentives support BEVs. The total cost of ownership assessment is used to evaluate the entire cost of a vehicle to find the most economical option among different powertrains. This study compares 2W (two-wheeler) and 4W (four-wheeler) BEV’s cost vis-à-vis equivalent ICEVs in Delhi and Mumbai. The cost analysis assesses the current and future government policies to promote BEVs. Two assumed policies were applied to estimate future scenarios. Annual distance traveled, battery replacement assumptions, and fuel/electricity prices were used for sensitivity analyses. It was found that the total cost of ownership of 2W BEVs in Mumbai and Delhi was lower than the ICEVs, only if heavily supported by government subsidies and incentives. In contrast, with assumed future policies, owning 4W BEVs was costlier, even with government subsidies. This study showed that if a vehicle travels more than the average annual distance traveled, BEVs can be a better option and make sense for niche applications such as taxi fleet operations or ride-hailing services. The current incentives were much more for 4W than 2W, implying a disproportionate allocation of subsidies to the wealthier, who can afford 4W vehicles. The funds required for subsidies, losses in fuel taxes because of lower sales, and tax exemptions offered to BEVs could cost up to ₹146,062 crores (i.e., $19 billion) annually to the Indian government in 2030, which is ~ ₹973 per capita, excluding investments required to build charging infrastructure. Therefore, India needs a targeted subsidy allocation plan, prioritizing 2W, and a phased strategy for an orderly and inclusive transition to a sustainable mobility future. Graphical Abstract
Kumar, Deepak, Abdul-Manan, Amir F. N., Kalghatgi, Gautam, Agarwal, Avinash Kumar
Well-To-Wheels Analysis of CO2 Emissions from a Conventional Taxi Fleet Replaced by Electric Vehicles2020-36-00743/26/2021
This paper presents a Well-to-Wheels (WTW) analysis of equivalent carbon dioxide (CO2eq) emissions in different scenarios of replacement of a conventional taxi fleet by electric vehicles. Two battery electric vehicles and one hybrid electric vehicle were used in the comparison with the conventional vehicle fleet. A numeric model was developed to evaluate CO2eq emissions in the fuel production, electricity supply, and vehicle operation phases. Gasoline and sugarcane ethanol were considered as fuels for the conventional and hybrid electric vehicles. Six scenarios of conventional vehicles replacement by electric vehicles in the taxi fleet were evaluated. The results showed that the replacement of nearly 13% of the current taxi fleet of a major city by the three electric vehicle models considered in the analysis could reduce CO2eq emissions by about 6%. If the entire fleet was replaced in a 5 years period, CO2eq emission could reach a reduction up to 82%.
Teixeira, Ana Carolina Rodrigues, Sodré, e José Ricardo
Carbon Emission Research of Taxi Fleet from ICEV to BEV (Shanghai Case)2021-01-50091/22/2021
Based on the life cycle assessment method, this paper takes Shanghai taxi fleet as the research objective (traditional fuel vehicle (ICEV) and battery electric vehicle (BEV)). Under the condition of Shanghai energy structure, and combined with the actual application scenario of Shanghai taxi fleet, the study and prediction of carbon emission is carried out from three stages of manufacture, use and recycle. The research results show that: in the life cycle, under the current energy structure and battery technology of the taxi fleet in Shanghai, the carbon emission of BEV and ICEV will be at the same level at the mileage of 50,000 km. With the adjustment of energy structure, the progress of battery technology and the increase of the proportion of battery electric taxi fleet, the overall carbon emission of Shanghai taxi fleet will be reduced significantly. The progress of battery technology, especially the increase of cycle life, has the most obvious effect on the reduction of overall carbon emission.
Liu, Bo, Li, Liguang
Congestion-busting with Autonomous Shuttles20AVEP03_103/1/2020
GoMentum is safety-testing two Local Motors shuttles at AAA's expansive NorCal proving grounds and new V2X lab. It was uneventful when an eight-passenger, low-speed driverless shuttle crawled at about 10 mph (16 km/h) toward the intersection at the GoMentum Station AV proving grounds in Concord, Calif. The crisp morning temperatures didn't get any more exciting when a mechanical pedestrian-dummy intentionally moved in the self-driving vehicle's path. The shuttle's six lidars, six radars and two military-grade GPS units brought the slow-moving vehicle gently to a stop within a courteous distance usually not granted by human drivers. The demo was dull for the handful of journalists on hand. But Jay Rogers, the chief executive of Local Motors-the producer of the shuttle dubbed “Olli” - was bubbling with enthusiasm. Rogers believes that the potential for low-speed connected and autonomous shuttles outweighs the promise of conventional vehicles transformed into full-stack robo-taxis.
Berman, Bradley
Taking a City’s Pulse with Moveable SensorsTBMG-351979/1/2019
Suppose you have 10 taxis in Manhattan. What portion of the borough’s streets do they cover in a typical day?
Feasibility Analysis of Taxi Fleet Electrification using 4.9 Million Miles of Real-World Driving Data2019-01-03924/2/2019
Ride hailing activity is rapidly increasing, largely due to the growth of transportation network companies such as Uber and Lyft. However, traditional taxi companies continue to represent an important mobility option for travelers. Columbus Yellow Cab, a taxi company in Columbus, Ohio, offers traditional line-of-sight hailing as well as digital hailing through a mobile app. Data from Columbus Yellow Cab was provided to the National Renewable Energy Laboratory to analyze the potential for taxi electrification. Columbus Yellow Cab data contained information describing both global positioning system trajectories and taxi meter information. The data spanned a period of 13 months, containing approximately 70 million global system positioning system points, 840 thousand trips, and 170 unique vehicles. A variety of scenarios were evaluated using Columbus Yellow Cab data and the Electric Vehicle Infrastructure Projection Tool (EVI-Pro) to understand challenges and opportunities associated with operating an electrified taxi fleet. Two main factors-access to home charging and vehicle specifications-are shown to be major variables affecting successful electric fleet operation. The analysis indicates that 95.7% of taxi travel days can be successfully completed by a 250-mile-range electric vehicle assuming access to overnight and public charging infrastructure. However, when no overnight access is available to fleet vehicles, only 39.9% of taxi travel days are possible with 250-mile range electric vehicles. An additional scenario, reducing the vehicle range from 250 miles to 100 miles (while controlling for infrastructure access and permitting overnight charging) resulted in only 34.4% of taxi travel days being completed.
Moniot, Matthew, Rames, Clement, Burrell, Erin
Driver´s View on the Introduction of Electric Vehicles in the Taxi Fleet of a Brazilian Large City2017-36-008911/7/2017
In Brazil, since the purchase cost of an electric vehicle (EV) is still very high, the exchange of a conventional vehicle by an EV would only be worth if the vehicle was used as source income, such as the case of taxis. Short run distances and high daily mileage make conventional taxis ideal candidates to be replaced by battery EVs. Recently, São Paulo and Rio de Janeiro received EVs as a test project, but other major cities, such as Belo Horizonte, have yet to be tested. The taxi fleet in this city has currently 7,152 vehicles, all powered by internal combustion engines, significantly contributing to equivalent carbon dioxide (CO2eq) emissions since the daily distance traveled is high. With the aim to characterize the fleet and evaluate taxi driver’s option to EVs, data was collected from a systematic sample of taxi stands, of a total of 375, through a structured interview with the drivers, considering a finite and homogeneous population. The results from the interviews conducted showed that the lack of information about EVs and their advantages are predominant among the drivers. About 68% of the interviewees never saw a hybrid or pure EV in the city streets. Factors such as purchase cost and lack of information and government incentives were the most cited by the drivers as barriers to exchange their conventional taxis by electric ones.
Teixeira, Ana Carolina Rodrigues, Sodré, José Ricardo
Motor Vehicle Seating ManualJ782_201411 (Current)11/19/2014
Human Accom and Design Devices Stds Comm
Evaluation of Engine Oil Performance with B5 and B20 Biodiesel in a Taxi Fleet Test2012-01-17069/10/2012
The addition of 7% FAME (Fatty Acid Methyl Ester) is mandated in a number of European countries since 2008. Higher FAME concentrations up to 30% are used by fleets in some countries. Passenger car manufacturers have reported on the negative technical implications of biodiesel on engine oil dilution, engine cleanliness and corrosion. The reason for the impact of FAME can be attributed to the higher boiling point compared to fossil fuel and the lower oxidation stability due to the presence of unsaturated fatty acid components. In this study engine oils with different performance level were evaluated in a taxi fleet test run with B5 and B20 biodiesel. The test results are illustrated with the used oil analyses and the performance of the engine oils by end-of-test engine inspections. The main conclusions from this taxi test are: B5 and B20 fuel affect piston cleanliness significantly depending on the engine type, deposits are formed with low levels of bio fuel concentration in the sump, and the reduction in piston cleanliness is comparable between B20 and B5.
Bunemann, Thomas F., Carress, Peter, Weiser, Heinrich, Bellgardt, Frank
Development of New CNG-Gasoline (Bi-fuel) Lubricant, by Taxi Fleet Screening Test and Field Trial in Thailand2012-01-16229/10/2012
An internal combustion engine operating on compressed natural gas (CNG) as fuel is usually under higher thermal stress compared to the same engine using gasoline fuel. This leads to various concerns on the operation of CNG engine and the performance of the lubricant, such increased wear, accelerated total base number depletion, and faster deterioration of the lubricant. Engine oil intended for compressed natural gas (CNG)-gasoline bi-fuel passenger car application must therefore be formulated to withstand the varied and often severe operating conditions, as well as maintain superior lubrication control and prolong engine life. PTT Public Company Limited (PTT) has developed a new CNG-gasoline lubricant meeting API SN/GF-5 performance category that is able to address the various operating concerns of bi-fuel passenger car engines, and at the same time provides extended oil drain interval (ODI) capability. This formulation development comprised of two rigorous field trial phases conducted in Bangkok, Thailand. The first phase involved the screening of various candidate formulations developed by PTT in a fleet of high mileage bi-fuel taxi vehicles. A final candidate formula was selected for further proof of performance in the second phase controlled field trial. This second phase controlled field trial was carried out on five new bi-fuel vehicles and two new conventional gasoline vehicles, and at an extended ODI of up to 25,000 km as compared to original recommended 10,000 km ODI. The engines of 3 field trial vehicles were inspected at the end of trial. The CNG-gasoline bi-fuel engines were observed to in excellent condition with minimum sludge & deposit issue, as well as an excellent used oil analysis (UOA) result throughout the trial. Despite the trial was run at extended ODI, the nitration/oxidation number and total acid number (TAN) growth/total base number (TBN) depletion were well-controlled. In addition, the candidate formula exhibited minimal engine wear, superior piston deposit ratings, as well as rendering potential fuel economy benefit. The candidate formula has shown to exceed the performance requirement for the latest CNG-gasoline (bi-fuel) passenger cars, and even for high mileage bi-fuel taxi vehicles under severe driving conditions in Bangkok, Thailand.
Predapitakkun, Sunthorn, Chia, Boon Ping, Rungwanitcha, Chetwana, Tang, Tristan
Maintaining reliabilityAEROJAN06_021/1/2006
Regional airlines and business jet operators care about fuel efficiency, just not as much as engine reliability. While fuel costs have risen to the number-two cost driver after salaries for most mainline carriers, managers and engineers at regional airlines and corporate operators still name reliability as their top priority-even over fuel efficiency. “After safety, reliability is really the only thing we can sell,” said Gene Hahn, Vice President of Flight Operations for Horizon Air. “It is imperative we are able to operate and that people can count on us.”
Rosenberg, Barry
Evaluation of SAE 0W-20 GF-4 Prototype Formulation in Severe Taxi Fleet Service2005-01-381810/24/2005
This paper reviews the relative performance of prototype SAE 0W-20 and SAE 5W-20 ILSAC GF-4 [1, 2] mineral oils in severe taxi fleet service. Both oils contained the same additive technology, formulated to 0.05% mass Phosphorus. This level was targeted to gain field experience with oils formulated to meet proposed chemical limits for the ILSAC GF-4 specification [1, 2]. Though the limits in the final ILSAC GF-4 specification were increased to 0.08% mass Phosphorus, the 0.05% mass Phosphorus maximum is again proposed for the ILSAC GF-5 specification [3]. Used oil Chemical and Physical analysis was carried out at both interim and final drains (10,000 miles). Oil and fuel consumption were also monitored during the test. After a total mileage accumulation of 100,000 miles per vehicle, engine teardowns and physical ratings were performed on key engine components. It was concluded the performance of both lubricants was equivalent and acceptable. An exception to this was the fuel economy benefit of the SAE 0W-20 grade.
Damen, Amanda, Broom, Nigel, Hartley, Rolfe, Riley, Michael
Improving Engine Coolant System Performance with the Science of Sealing Technology; Part III. Compact Seal Design2005-01-17674/11/2005
Auto manufacturers continue to push the limits of vehicle longevity to new extremes. Life expectancy has grown from 100,000 to 150,000 miles and OEMs have their targets set on the 300,000 mile mark. However, as this mandate for longer life continues to extend, suppliers are challenged to design and manufacture materials and products that will offer the same life expectancy and durability as other major components. For example, the water pump seal - the most crucial component within the coolant system - experiences extreme wear. Current seal face materials simply do not allow the seal to achieve the 300,000 mile goal. Therefore, new advanced materials - highly resistant to wear and system upsets - are required if components are to offer the durability and the efficiency required to meet the growing mileage milestone. This paper will discuss the development of a robust seal - the Global Compact Seal (GCS) - designed to tolerate adverse conditions in water pumps, as validated by testing on a Las Vegas taxi fleet.
Ajram, Sam, Shefren, Phil
Success by designAUTOAUG04_018/1/2004
Toyota is working to differentiate itself from the competition by continually evolving its unique design philosophy. The hills of Nagakute, 20 km (12 mi) east of Nagoya city, were the battleground between the two powerful warlords, Toyotomi and Tokugawa, in 1584 in feudal Japan. Tokugawa scored a decisive victory, paving the way for establishment of the House of Shogun. Toyota Motor Corp. is often likened to the Shogun for its might and main, the automaker securing an over-50% share of the Japanese domestic market. Nagakute is now the site of a more peaceful event, the forthcoming 2005 Aichi Earth EXPO, the theme of which is the preservation and enhancement of the global environment. Over 125 nations participate in the EXPO, as well as numerous private enterprises and companies. Toyota's presence will be prominent with many vehicular and other exhibits, both mobile and stationary. The chairman of the EXPO organizing committee is Shoichiro Toyoda, Honorary Chairman of Toyota Motor Corp.
Yamaguchi, Jack
Appetite for cars growing in ChinaAUTOAUG03_018/1/2003
Automakers and suppliers the world over are scrambling to establish or expland manufacturing operations in China as income growth spurs a rapid rise in car sales. With a population four times that of the U.S., China is too massive a potential mass market to miss-or dismiss. Automotive OEMs and suppliers from across the globe are intent on cultivating as large a mass market as the country's Communist rule will accommodate. They aren't about to let stand in the way little things such as a viral epidemic and a native engineering community that has little behind-the-wheel experience. And neither are their Chinese partners. An increase of about 50% in passenger vehicle sales from 2001 to 2002 is evidence that engineering inexperience and other growing pains are not deterring growth. At 1,126,000, passenger car purchases surpassed 1 million for the first time last year. Overall vehicle sales, including trucks and buses, totaled 3.25 million in 2002.
Ponticel, Patrick
Effects of Engine Oil Formulation Variables on Exhaust Emissions in Taxi Fleet Service2002-01-268010/21/2002
The relationship between engine oil formulations and catalyst performance was investigated by comparatively testing five engine oils. In addition to one baseline production oil with a calcium plus magnesium detergent system, the remaining four oils were specifically formulated with different additive combinations including: one worst case with no detergent and production level zinc dialkyldithiophosphate (ZDTP), one with calcium-only detergent and two best cases with zero phosphorus. Emissions performance, phosphorus loss from the engine oil, phosphorus-capture on the catalyst and engine wear were evaluated after accumulating 100,000 miles of taxi service in twenty vehicles. The intent of this comparative study was to identify relative trends. The study found that contamination of catalysts by phosphorus adversely affects emissions of hydrocarbons, carbon monoxide and nitrogen oxides and, for the observed levels of captured phosphorus, emissions degradation correlates directionally with the amount found on the close-coupled catalysts. The vehicles operating with an experimental oil containing ZDTP but without detergent resulted in the largest deterioration of emission system performance and the greatest amount of phosphorus captured onto the catalyst. Phosphorus transport by selective volatilization of phosphorus components from the oil was found to be a significant factor. There was no evidence that abnormal or excessive wear or corrosion occurred based on used oil wear metal data.
Johnson, Milton D., McCabe, Robert W., Hubbard, Carolyn P., Riley, Michael J., Kirby, Charles W., Ball, Douglas J., Tripp, Glenn, McDonnell, Thomas F., Lam, William Y.
Development of a Piston Ring-Cylinder Bore Wear Model2000-01-17886/19/2000
In an internal combustion engine, the wear in the piston ring/cylinder bore contact initially increases rapidly due to run-in and then attains a steady state during which the engine spends most of its useful life. This paper describes the development of an abrasive wear model for both cylinder bore and piston rings for the steady state period. The model took into account shear thinning of the lubricant, but it did not consider the effects of transient operations, geometry changes due to bore distortions, ring twist, ring motion, and corrosion. The model predicted the bore wear depth distribution from the top dead center (TDC) to the bottom dead center (BDC) and ring wear depth under different operating conditions. The maximum bore wear depth was predicted to occur at about 20 degrees after TDC where the combustion gas pressure reached its peak value. The model predicted an increase in bore and ring wear depth with increasing engine speed. Doubling the ring tension increased wear depth of both the cylinder bore and the ring. The ring face curvature influenced ring wear depth more significantly than bore wear depth. The model was validated by measuring bore wear near TDC on 3.0L Taurus and 4.6L Crown Victoria obtained from customers with 50 - 150 K miles and 3.0 L Windstar from Las Vegas Taxi Fleet. A reasonable correlation was observed between the predicted and the measured bore wear.
Gangopadhyay, Arup
Engine Treatment Product Fleet Test and Engine Component Analysis98244010/19/1998
A fleet test study was initiated to compare the use of a unique boundary chemistry (UBC) containing PTFE engine treatment, as a supplement to a current 10W-30, API SJ/GF-2 motor oil, versus the use of the oil without any supplement. The test was conducted with a taxi fleet of 1998 Chrysler 2.4L minivans. The factory-fill oil was drained after 5 thousand km and the group of vehicles entered the test program designed as a double-blind study, wherein, neither the drivers nor analysts knew the identities of reference and treated engines. Half of the taxis received a one-time application of the engine treatment. Subsequent oil drain intervals were conducted every 6.5 thousand km so that at 11 thousand km a baseline and treated engine were pulled from the vans and sent to the laboratory for analysis. The rest of the fleet continued on to 50 thousand km, six oil changes later, when two more engines were obtained as before. The last data point was at the 82 thousand km mark. Wear metal analysis of the drain oils was performed at each oil drain interval. The camshaft lobes were photographed, measured and then sectioned to remove the nose and foot of representative specimens for surface analysis by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). This revealed the presence of PTFE surface features, in addition to, the formation of iron fluoride on components subjected to boundary lubrication conditions. These same tribochemical films and PTFE inclusions were still detectable at the high mileage accumulation points. This illustrated that a one-time, initial treatment of UBC displayed a carryover effect in terms of anti-wear film formation. Hypotheses and mechanisms are proposed to account for the analytical and physical observations.
Pistillo, W. Rocco
Base Oil and Additive Effects in the Thermo-oxidation Engine Oil Simulation Test (TEOST)96203810/1/1996
The new ILSAC GF-2 specification for passenger car motor oils includes the TEOST bench test as an indicator of the deposit forming tendencies of motor oils. Base oils, base oil / additive component mixtures, and fully formulated motor oils were run in the TEOST apparatus. Some of the used oils and deposits were analyzed using FTIR spectroscopy and x-ray photoelectron spectroscopy. The results of these experiments show that the base oil fraction of the lubricant, which may range from conventional solvent refined mineral oils to high VI hydrocracked or synthetic PAO, contributes very little to the TEOST's total deposits (< 5 mg, < 60 mg = “pass”). In contrast, lubricant performance in industry standard gasoline engine tests and taxi fleet tests is typically highly sensitive to base oil composition. Furthermore, additives designed to reduce wear, provide anti-oxidancy and lower friction substantially increase the amount of TEOST deposits. This suggests that the deposit forming mechanisms in the TEOST, originally correlated to turbocharger deposits, may be different from those observed in tower temperature regions of gasoline engines.
Stipanovic, A J., Schoonmaker, J. P, de Paz, E. F, Mowlem, J K, Broas, J E, Thiel, C Y.
The Impact of Intake Valve Deposits on Exhaust Emissions92225910/1/1992
This paper presents the results of a twenty- vehicle program designed to determine the functional relationship between intake valve deposit level and exhaust emissions. The “identical” 1990 model year vehicles used for this program had accumulated over 80,000 kilometers in taxi fleet service and had developed average intake valve deposit levels which ranged from 6 to 9 on the Coordinating Research Council merit scale. The exhaust emissions from these vehicles were measured in triplicate tests using the 1975 Federal Test Procedure. The intake valve deposits were then mechanically cleaned in-situ, and exhaust emissions were again measured in triplicate. Special procedures were followed to minimize vehicle-to- vehicle variability and to obtain statistically meaning ful results. Results showed intake valve deposits to have a significant adverse effect on exhaust emissions. The relationship between intake valve deposit ratings and tailpipe emissions was determined to be linear with heavier deposits causing higher emissions. While this program focused on one particular engine and vehicle model, it is expected that the observed effects are not unique.
Houser, K. R., Crosby, T. A.
Engine Oil Formulation Effects in Severe Field Service and Sequence VE Tests92230210/1/1992
A series of SAE 5W-30 and SAE 10W-30 engine oils was evaluated in a New York City taxi fleet to study the performance of prototype API SG engine oils. Key formulation variables studied were SAE viscosity grade and Viscosity Index improver chemistry. A good correlation was established between Sequence VE sludge and varnish results and field performance. The deposit control value of dispersant Viscosity Index improvers was demonstrated. Formulations based on polymethacrylate Viscosity Index improvers performed directionally better in the field than the Sequence VE results predicted. Overall, the field performance of API SG quality oils was excellent.
Flamberg, Alan, Hyndman, Charles W., Machleder, Warren H.
The Role of Alternative Fuels in Reducing Emissions from Mobile Sources in Taiwan R.O.C.92228010/1/1992
Urban areas in Taiwan frequently experience unhealthy levels of particulate, ozone, and carbon monoxide. The Taiwan Environmental Protection Administration, formed in 1987, has begun an aggressive program to improve air quality by addressing all major sources of air pollution. Mobile emissions sources are responsible for over 90 percent of CO, NOx, and HC emissions in the Taipei area. New emissions standards for light-duty vehicles and motorcycles took effect in 1990 and 1991, respectively; these standards are expected to significantly reduce emissions from these vehicle classes as the new models are phased into the vehicle population. However, additional reductions may be needed in Taipei and other urban areas. Alternative fuels-including liquefied petroleum gas (LPG), natural gas, methanol, ethanol, and electricity-represent a promising strategy for achieving these reductions. Vehicle technology for these fuels is being developed rapidly throughout the world. However, limited work is being done on motorcycles, which represent a large part of Taiwan's emissions inventory. Significant amounts of LPG and natural gas may be available in Taiwan for vehicular use within the next ten years. The Taipei taxi fleet is a potential initial market for use of LPG or another alternative fuel.
Luscher, Daniel R., Jackson, Michael D., Walsh, Michael P., Hsu, Charles C. F.
Demonstration of a Catalyst Retrofit System to Reduce Vehicle Emissions within Mexico City90211710/1/1990
Mexican automobile manufacturers will begin to phase in catalytic converters on new models during the early 1990's. A more immediate concern that needs to be addressed is the large remaining older car population that will continue to pollute the air. Retrofitting these vehicles with catalytic converters is one of the alternatives being considered in a collective effort to improve Mexico City's air quality. In collaboration with Mexico City government officials, a vehicle demonstration was designed to show the benefits of an oxidation catalyst retrofit. This paper presents emission results of Mexico City's taxi fleet vehicles and displays the effectiveness of a Pt/Pd oxidation catalyst system in lowering emission levels. Two fleet vehicles were emission tested before and after catalyst retrofit modifications with the U.S. FTP-75 vehicle test method. Carburetor modifications were also included to study the effects of engine tuning on engine emissions and catalyst performance. A catalyst retrofit is one approach for achieving reductions in emissions. Prerequisites to a catalyst retrofit are the availability of lead free fuel and proper engine maintenance schedules.
Skowron, John F., Scaparo, John A.
Injector Deposits — The Tip of Intake System Deposit Problems86153410/1/1986
A comprehensive program encompassing laboratory engine, laboratory vehicle, and taxi fleet tests was undertaken to evaluate fuel variables and induction system deposits in modern spark-ignition engines. The widespread fuel injector deposit problem was the primary focus. Injector and vehicle design, driving cycle, and fuel composition were found to be major contributing factors to injector deposition. Commercial gasoline additives capable of preventing and removing injector deposits were also identified. Some of these additives control intake valve and port deposits as well, while others actually contribute to valve and port deposits. Like injector deposits, intake valve and port deposits are shown to have adverse effects on vehicle performance. Associated functional problems may be even more apparent in high-swirl, fast burn engines.
Taniguchi, Brian Y., Peyla, Richard J., Parsons, Gary M., Hoekman, S. Kent, Voss, Douglas A.
Variability Among Engine Raters6301311/1/1963
Final engine tests on a new crankcase motor should be fast and economical yet able to discriminate between oils of high quality. Tests should be properly designed in advance to obtain optimum quantity of information, and the expected variability and its sources should be known. However, the experiment can be designed to partition and measure this variability for use in future experimental designs for the same or similar test methods. This paper describes the method of partitioning and measuring variance due to choice of raters that was encountered in treating data obtained from a taxi fleet test.
Gorry, L. J.
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