scholarly journals A New Dawn for Diesel

2005 ◽  
Vol 127 (01) ◽  
pp. 26-31
Author(s):  
John DeGaspari

This article reviews that diesel engines are more expensive than gasoline engines and the lower fuel prices in the United States make buying decisions based on fuel economy alone unlikely. Many of the advancements have gone largely unnoticed by US drivers, who still view diesels as workhorses for large trucks. But some proponents of diesel say that a combination of higher torque, better fuel economy, and smooth, quiet engine performance could sway a significant number of drivers here to consider diesels for smaller, personal-use vehicles. Diesels provide better fuel efficiency than gasoline engines do and are well suited to heavy loads and continuous driving. Hauling a heavy load up a steep grade, the difference in fuel economy could be as high as 75 percent compared to conventional gasoline engines. Diesels could make a bigger impact on fuel consumption from a fleet perspective in this country, where people favor larger vehicles, than in Europe. Diesels deliver higher torque at lower speeds than gasoline engines, allowing drivers to get away with a comparatively smaller, lower horsepower diesel without sacrificing acceleration or towing capacity.

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.


Author(s):  

The prospects of using hydrogen as a motor fuel are noted. The problems that arise when converting a diesel engine to run on hydrogen are considered. The features of the organization of the working process of enginesrunning on hydrogen are analyzed. A method of supplying a hydrogenair mixture to a diesel engine is investigated. To supply hydrogen to the engine cylinders, it is proposed to use the Leader4M installation developed by TechnoHill Club LLC (Moscow). Experimental studies of a stationary diesel engine of the D245.12 S type with the supply of hydrogen at the inlet obtained at this installation are carried out. At the maximum power mode, the supply of hydrogen from this installation to the inlet of the diesel engine under study was 0.9 % by weight (taking into account the difference in the calorific value of oil diesel fuel and hydrogen). Such a supply of hydrogen in the specified mode made it possible to increase the fuel efficiency of the diesel engine and reduce the smoke content of exhaust gases, carbon monoxide and unburned hydrocarbon emissions. Keywords internal combustion engines; diesel engine; diesel fuel; hydrogen; hydrogenair mixture; fuel efficiency; exhaust gas toxicity indicators


Author(s):  
Danilo J. Santini ◽  
Philip D. Patterson ◽  
Anant D. Vyas

Toyota’s introduction of a hybrid electric vehicle (HEV) named “Prius” in Japan and Honda’s proposed introduction of an HEV in the United States have generated considerable interest in the long-term viability of such fuel-efficient vehicles. A performance and cost projection model developed entirely at Argonne National Laboratory (ANL) is used to estimate costs. ANL staff developed fuel economy estimates by extending conventional vehicle modeling done primarily under the National Cooperative Highway Research Program. Together, these estimates are employed to analyze dollar costs versus benefits of two of many possible HEV technologies. Incremental costs and fuel savings are projected for a Prius-type low-performance hybrid (14.3-s 0 to 60 mph acceleration, Z60 time) and a higher-performance “mild” hybrid vehicle (11-s Z60 time). Each HEV is compared with a U.S. Toyota Corolla with automatic transmission (11-s Z60 time). The base incremental retail price range, projected a decade hence, is $3,200–$3,750, before considering battery replacement cost. Historical data are analyzed to evaluate the effect of fuel price on consumer preferences for vehicle fuel economy, performance, and size. The relationship among fuel price, the level of change in fuel price, and consumer attitude toward higher fuel efficiency also is evaluated. A recent survey on the value of higher fuel efficiency is presented and U.S. commercial viability of the hybrids is evaluated using discount rates of 20 percent and 8 percent. The analysis, with its current HEV cost estimates and current fuel savings estimates, implies that the U.S. market for such HEVs would be quite limited.


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):  
Qinghua Lin ◽  
Pingen Chen

Abstract Lean burn gasoline engines have attracted more and more attentions over the past two decades. One of the main challenges in commercializing lean burn gasoline engines in the United States is lean NOx control to meet the stringent NOx emission regulation. Several types of lean aftertreatment systems including passive selective catalytic reduction (SCR) systems and lean NOx traps (LNTs), have been intensively investigated to meet the NOx emission requirements without triggering significant penalties on fuel efficiency. One of the most promising technologies to achieve this goal is non-uniform cylinder-to-cylinder combustion (NUCCC) control strategies. However, successful implementation of NUCCC strategies are challenging tasks since it may cause cylinder-to-cylinder torque imbalance and thus deterioration of drivability. The purpose of this study is to propose and evaluate a systematic method for generating the references of fuel quantity and air quantity for different cylinders to simultaneously achieve cylinder-to-cylinder torque balance and non-uniform cylinder-to-cylinder air/fuel ratio (AFR) for multi-cylinder engines in various scenarios. To validate the effectiveness of the proposed method, simulation studies were carried out using a multi-zone engine model. The simulation results show that, the proposed references, if successfully tracked, can lead to torque balance across the cylinders as well as non-uniform cylinder-to-cylinder AFR.


Author(s):  
N.S. Mustafa ◽  
N.H.A. Ngadiman ◽  
M.A. Abas ◽  
M.Y. Noordin

Fuel price crisis has caused people to demand a car that is having a low fuel consumption without compromising the engine performance. Designing a naturally aspirated engine which can enhance engine performance and fuel efficiency requires optimisation processes on air intake system components. Hence, this study intends to carry out the optimisation process on the air intake system and airbox geometry. The parameters that have high influence on the design of an airbox geometry was determined by using AVL Boost software which simulated the automobile engine. The optimisation of the parameters was done by using Design Expert which adopted the Box-Behnken analysis technique. The result that was obtained from the study are optimised diameter of inlet/snorkel, volume of airbox, diameter of throttle body and length of intake runner are 81.07 mm, 1.04 L, 44.63 mm and 425 mm, respectively. By using these parameters values, the maximum engine performance and minimum fuel consumption are 93.3732 Nm and 21.3695×10-4 kg/s, respectively. This study has fully accomplished its aim to determine the significant parameters that influenced the performance of airbox and optimised the parameters so that a high engine performance and fuel efficiency can be produced. The success of this study can contribute to a better design of an airbox.


2020 ◽  
Vol 41 (3) ◽  
pp. 192-197
Author(s):  
Sherry S. Zhou ◽  
Alan P. Baptist

Background: There has been a striking increase in electronic cigarette (EC) use in the United States. The beliefs and practices toward ECs among physicians are unknown. Objective: The purpose of this study was to investigate EC practice patterns among allergists, pulmonologists, and primary care physicians. Methods: An anonymous survey was sent to physicians. The survey contained 32 questions and addressed issues related to demographics, cessation counseling behaviors, personal use, and knowledge and beliefs about ECs. Statistical analysis was performed by using analysis of variance, the Pearson χ2 test, Fisher exact test, and logistic regression. Results: A total of 291 physicians completed the survey (222 primary care physicians, 33 pulmonologists, and 36 allergists) for a response rate of 46%. The allergists asked about tobacco cigarette use as frequently as did the pulmonologists and more than the primary care physicians (p < 0.001), but they rarely asked about EC use. The pulmonologists scored highest on self-reported knowledge on ECs, although all the groups answered <40% of the questions correctly. The allergists did not feel as comfortable about providing EC cessation counseling as did the pulmonologists and primary care physicians (p < 0.001). All three groups were equally unlikely to recommend ECs as a cessation tool for tobacco cigarette users. Conclusion: Allergists lacked knowledge and confidence in providing education and cessation counseling for EC users. As the number of patients who use these products continues to increase, there is an urgent need for all physicians to be comfortable and knowledgeable with counseling about ECs.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4491
Author(s):  
Changchun Xu ◽  
Haengmuk Cho

Due to the recent global increase in fuel prices, to reduce emissions from ground transportation and improve urban air quality, it is necessary to improve fuel efficiency and reduce emissions. Water, methanol, and a mixture of the two were added at the pre-intercooler position to keep the same charge and cooling of the original rich mixture, reduce BSFC and increase ITE, and promote combustion. The methanol/water mixing volume ratios of different fuel injection strategies were compared to find the best balance between fuel consumption, performance, and emission trends. By simulating the combustion mechanism of methanol, water, and diesel mixed through the Chemkin system, the ignition delay, temperature change, and the generation rate of the hydroxyl group (−OH) in the reaction process were analyzed. Furthermore, the performance and emission of the engine were analyzed in combination with the actual experiment process. This paper studied the application of different concentration ratios of the water–methanol–diesel mixture in engines. Five concentration ratios of water–methanol blending were injected into the engine at different injection ratios at the pre-intercooler position, such as 100% methanol, 90% methanol/10% water, 60% methanol/40% water, 30% methanol/70% water, 100% water was used. With different volume ratios of premixes, the combustion rate and combustion efficiency were affected by droplet extinguishment, flashing, or explosion, resulting in changes in combustion temperature and affecting engine performance and emissions. In this article, the injection carryout at the pre-intercooler position of the intake port indicated thermal efficiency increase and a brake specific fuel consumption rate decrease with the increase of water–methanol concentration, and reduce CO, UHC, and nitrogen oxide emissions. In particular, when 60% methanol and 40% water were added, it was found that the ignition delay was the shortest and the cylinder pressure was the largest, but the heat release rate was indeed the lowest.


2010 ◽  
Vol 13 (2) ◽  
Author(s):  
John F Cogan ◽  
R. Glenn Hubbard ◽  
Daniel Kessler

In this paper, we use publicly available data from the Medical Expenditure Panel Survey - Insurance Component (MEPS-IC) to investigate the effect of Massachusetts' health reform plan on employer-sponsored insurance premiums. We tabulate premium growth for private-sector employers in Massachusetts and the United States as a whole for 2004 - 2008. We estimate the effect of the plan as the difference in premium growth between Massachusetts and the United States between 2006 and 2008—that is, before versus after the plan—over and above the difference in premium growth for 2004 to 2006. We find that health reform in Massachusetts increased single-coverage employer-sponsored insurance premiums by about 6 percent, or $262. Although our research design has important limitations, it does suggest that policy makers should be concerned about the consequences of health reform for the cost of private insurance.


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