Relationship cooling effect and octane rating

relationship cooling effect and octane rating

Section 3 reflects on the impact of evolving engine technology on octane booster . discussed cooling effect of GDI on the unburnt gas temperature [10], [11]. Based on the data from these surveys, a correlation for the Road Octane Number, . Effects of engine knocking range from inconsequential to completely destructive .. Flat flame burners are also suitable for the production of cool flames of hydrocarbons. parameters and their relation to octane number of a fuel. This section. was that the charge cooling effect produced by an ethanol blend was of approximately the same magnitude as the chemical octane number.

AFR data are from test averages in G. For example, inthe Los Angeles County Board of Supervisors defined a bromine number limit on gasoline to control olefins as eye irritants and ozone generation that went into effect in Neligan et al. Although these regulations were enacted, they were only applicable in California, with a limited impact on national tailpipe emissions or fuel economy until the EPA was formed in California Air Resources Board CARB Low regulatory oversight combined with high AKI and low-cost fuel provided insufficient economic motivation for automakers or consumers to desire improvements in fuel economy.

Instead, manufactures designed and marketed high-performance vehicles that consumers wanted, effectively marking — as the power wars in the U.

relationship cooling effect and octane rating

Regulation Age The unchecked quest for performance during the power wars age was quickly halted by emissions regulation resulting from urban air quality concerns and fuel economy regulation resulting from geopolitically motivated fuel shortages in the s. InCongress passed the Clean Air Act — the first national tailpipe emissions standard that regulated tailpipe emissions of carbon monoxide COvolatile organic compounds VOCsand oxides of nitrogen NOx — which went into full effect by Beyond tailpipe emissions, the Clean Air Act would impose additional regulations on gasoline formulation and additives.

Although there had historically been significant controversy over the effects of TEL Boyd, ; Rosner and Markowitz, ; Nriagu,quantitative evidence of a rise in lead exposure from human activity was not introduced until when Clair Patterson demonstrated an over fold increase in lead exposure during the mid-twentieth century as compared to before the industrial revolution Patterson, While trying to accurately date the age of the earth using lead isotope decay Patterson,he discovered that his instruments were affected by background lead contamination that was tied to the recent rise in environmental lead contamination, like that from leaded gasoline Needleman, Similar isotope dating techniques have since been used by several researchers who have found evidence that the use of lead in gasoline has had detrimental societal effects in North America Nriagu, ; Canfield et al.

Tetraethyl lead had other more direct and negative technical qualities; specifically, TEL tended to cause deposit formation inside the combustion chamber. It was found in the late s that anti-deposit fuel additives, such as dichloroethane and dibromoethane, were required to prevent metal deposits from rapidly forming on combustion chamber surfaces.

Gibbs,; Nriagu, However, these and other anti-deposit chemicals introduced halogenates into the exhaust. Initially, the exhaust halogenates were not of a concern, but once exhaust catalysts were needed to comply with the Clean Air Act ofthis changed.

Thus, to enable catalyst use inthe EPA defined the associated fuel lead phasedown process in U. Environmental Protection Agencyb. Tailpipe emissions were further reduced in when Congress amended the Clean Air Act to tighten the passenger car NOx standard from 3.

Byan additional passenger car phasedown in NOx to 1. Federal Test cycles of the s Kummer, Within a decade, NOx emissions were reduced by a factor of four, an aggressive phase that simultaneously required the introduction of unleaded fuel.

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Nearly 50 years after the first regulatory investigations into the use of lead in motor gasoline, it would be a technical motivation — to use catalysts to reduce smog forming emissions — and not a human health or environmental reason specifically related to lead toxicity that resulted in a regulatory-mandated reduction of fuel lead content.

Although the Clean Air Act mandated emissions control and unleaded fuel requirements for new vehicles, it took over 20 additional years and the amendments to the Clean Air Act to completely phase lead out of motor gasoline in As a response to emissions regulations, AFR was increased to aid in compliance with CO and VOC regulations, which in turn caused adiabatic flame temperature to also increase and, thus, increase NOx formation Lavoie et al.

At that time, catalyst technology was not sufficiently mature to reduce the associated increase in NOx to regulated levels Kummer, and, thus, this trade-off in emissions trends required relatively significant changes to engines.

Three-way catalysts that simultaneously reduce NOx while oxidizing CO and hydrocarbons were not fully phased in until the early s to meet more stringent NOx standards United States, Prior to the maturity of three-way catalysts, two-way catalysts were commonly used to control CO and HC emissions, but they required NOx emissions to be reduced in-cylinder by reducing in-cylinder temperatures while simultaneously reducing CO. The reduced compression ratio in this approach had an additional benefit in that it complemented the lower octane unleaded fuel, as seen by the rapid declines in Figures 2 and 4which reduced the AKI of regular grade by two points from 90 AKI in to 88 AKI in Neligan et al.

However, as NOx emissions control mandates became more stringent in the late s, full catalysis of CO, HC, and NOx would be required to meet them, as future opportunities to operate fuel-lean would limit future fuel economy improvements Kummer, Although emission mandates tended to increase AFR relative to values seen in the mids Figure 3reduced compression ratio requirements counteracted gains in fuel economy by fundamentally reducing the maximum and achievable efficiency of the engine Caris and Nelson, Figure 3 shows that the fuel economy of vehicles in the mids was actually higher than that of vehicles in the early s, Figure 4.

The full effect that fuel AKI reduction and emissions constraints had on fuel economy becomes apparent with the historical and political happenings of the s. While implementing the phase-in of unleaded fuel and emissions standards, the U. Department of State, Office of the Historian, Energy Information Administration,delivering a rapid shock to the economy. Motorist highway speeds slowed to federally mandated 55 mph speed limit, and automakers manufactured new vehicles to comply with newly imposed fuel economy standards Energy Policy and Conservation act 42 USC Specifically, the Energy Policy Conservation Act established average fuel economy standards of 15, 19, and 20 mpg for the model years MYs, andrespectively, and an eventual requirement of The phase-in of these regulations was timely as they coincided with a second oil crisis inwhich was caused by the Iranian Revolution.

Digital Age The regulatory age of the s proved to be a response period from the power wars age of the s and s and from fuel shortages influenced from geopolitical events. These advances were utilized both in design through computer-aided simulations and on-vehicle through rugged low-cost computing and electronic controls.

Both on-vehicle and in-design computational tools became critical to comply with increasingly stringent exhaust tailpipe emissions limits and fuel economy standards.

Integration of cost-effective computational power and sensing technologies provided dramatic improvements to performance and operation while complying with new emissions regulations through active engine management and three-way catalyst functionality Kummer, Research began to illustrate that improvements to engine operation could occur with technologies, such as active spark control Kraus et al.

Although reduced AKI of unleaded gasoline and a lack of maturity in emissions catalyst proved to be detrimental to engine compression ratio during the regulatory age, new engine management features and controls were found to enable increases in knock tolerance and associated compression ratio and performance without changes to fuel AKI. The ability to increase compression ratio allowed engines to regain some of the lost performance and efficiency associated with stoichiometric AFR operation as compared to rich or lean AFR operation, respectively.

One enabler came from the implementation of knock sensors — accelerometers to detect resonance frequencies in the 4—5 kHz range common to knock Hickling et al. The result was that the ECU and associated engine management strategies enabled engine compression ratio to increase with relatively constant fuel AKI Kraus et al.

Starting in the early s, tremendous improvement to performance, engine efficiency, and refinement occurred, all while fuel economy regulation remained stagnant. The combined effect of engine sensing and control improvements is seen in Figure 5where knock sensor deployment and port fuel injection PFI occurred simultaneously starting in approximately Because of the rapid adoption and improvement of on-board engine controls, was the last year that the Coordinating Research Council CRC conducted an octane survey of the MY vehicles as it had regularly done since the s.

The integration of on-board sensing, control technologies, such as variable valve timing VVTmulti-valve cylinder heads, and computer-aided design, and simulation helped to relax the historically tight coupling between fuel octane number and compression ratio Figure 1. Historically representative average trends in fuel delivery and engine technologies during the last 40 years.

While engine technology was being implemented in the digital age, the nominal value of fuel was flat and the real value of fuel adjusted to actually declined Figure 6.

The decreasing real value of fuel mirrored the fuel price trends during the power wars age. Moreover, with the introduction of engine technology, as fuel prices were declining and cost-effective performance increases became available, vehicle performance began to increase. Additionally, consumer response to decreased real value of fuel in the digital age was highlighted by consumer purchasing preference migrating from passenger cars to light trucks Although emissions regulations continued to become more stringent with Tier 1 and Tier 2 in andrespectively United States,significant advances in emission control technologies and on-board computational control helped to ease the integration of emissions regulation and prevent a major disturbance and correction such as the one that occurred during the regulation age.

These trends have been emphasized by Cheah et al. William, once again some of your post expressed in a very matter-of-fact style is complete and utter nonsense. I will pick particularly on Quote High Octane fuel actually evaporates much faster then lower octane fuel, if something is evaporating, creating heavy dense cool vapor, you can get more fuel into a cylinder. And more air and more oxygen.

Cold air contains more oxygen. High Octane fuel does not necessarily evaporate much faster. Both rates of evaporation are very similar. Both types of fuel are mixtures that contain some components that evaporate faster and some that evaporate slower, and rates of evaporation, provided they exceed a certain minimum, are quite irrelevant to the performance of a petrol engine.

There is some cooling associated with evaporation of fuel, but the total amount of cooling is proportional to the amount of fuel that evaporates, not to its rate of evaporation. The most important difference between a low octane and a high octane fuel is that the latter can more effectively limit the chain branching steps in the detailed mechanism of the combustion reaction that lead to explosions Cold air does not contain more oxygen than hot air.

Obviously 2 gram of cold air contains more oxygen than 1 gram of hot air. You can use that argument to say that a lemon is sweeter than a grape, because it contains more sugar! About the other parts of your post, some is OK, but boiling in the carburettor is equally undesirable for motors whether they run on high octane or low octane fuel, and no less likely to happen for high octane than low octane.

Octane rating - Wikipedia

In fact there is even a contradiction between your ideas that faster evaporation and less chance of boiling in the carburettor can go together -- boiling is simply a fast evaporation that occurs when the temperature of a liquid generates a vapour pressure that is equal to atmospheric pressure or, more precisely, the pressure in the local environment. You obviously have no experience with high octane fuels. High octane fuels have to be kept tightly capped or they will literally evaporate away on you, in a short period of time.

I would put their ability to evaporate with the best lacquer thinners there are. If you are talking about high octane fuels in terms of specialized racing blends, then you are quite right -- i do not have much experience. If you are talking about what you would buy as a premium blend at a petrol station then I have plenty of experience.

relationship cooling effect and octane rating

If you are talking about methanol, I also have plenty of experience of its general properties, though not of its use as an automotive fuel. When I am talking, on the other hand, about radical chain reactions and radical explosions, which are the scientific explanation of combustion processes, then I would venture to say that you probably have absolutely no experience nor even second hand knowledge. Boiling in the carburettor would certainly cause performance problems, but they do not bear any great connection with pinging, other than reducing fuel supply so that the engine runs lean, which does increase the balance of a very complicated combustion reaction more towards explosion.

With only fuel, lubricating oil and airflow to cool the engine and a "lean of peak" mixture with no "excess" fuel for cooling, the engine is only a few seconds of dangerously lean mixtures, autoignition and detonation away from catastrophic failure. Regional variations[ edit ] The selection of octane ratings available at the pump can vary greatly from region to region.

E85 unleaded fuel is also available at several United service stations across the country.

E85 Fuel Explained - Should you use it?

Two types of fuel are available at petrol stations in Bangladesh. In limited areas higher rating such as 98 RON is available. In some rural areas it can be difficult to find fuel with over 92 RON.

The three types are unleaded. However several fuel stations are phasing out 92 RON. All fuels are unleaded. Most cars run on 95, but 98 is available for vehicles that need higher octane fuel, or older models containing parts easily damaged by high ethanol content. Shell offers V-Power, advertised as "over 99 octane", instead of RE85 is only suitable for flexifuel cars that can run on high-percentage ethanol.

E85 is also available is most areas.

relationship cooling effect and octane rating

India's ordinary and premium petrol options are of 91 RON. The premium petrols are generally ordinary fuels with additives, that do not really change the octane value. Recently, Hindustan Petroleum launched poWer 99 with an RON value of 99 which is currently available only in Bangalore, Pune and now in Mumbai but expected to roll out in other major cities soon.

Indonesia's "Premium" gasoline rated at 88 RON. Starting from August Pertamina has started selling a new fuel variant rated at 98 RON marketed by the name of Pertamax Turbo, serving as a replacement for Pertamax Plus. Total and Shell stations only sell RON 92 and 95 gasoline. However, in earlyShell launched a new variant "Regular", rated at 90 RON and currently sold at certain locations.

relationship cooling effect and octane rating

Petronas has decided to shut down its retail business in Indonesia inafter years of sluggish sales. All variants are unleaded. Those values are defined in standard JIS K Sometimes "high octane" is sold under different names, such as "F-1".

relationship cooling effect and octane rating

Petron sells RON in selected outlets. Pemex Magna 87 AKI is sold as a "regular" fuel and is available at every station.