The so-called No. 90, No. 93, No. 97 unleaded gasoline, they contained 90 refers to the percentage, the percentage of 93, 97 percent strong resistance to knocking “isooctane,” that contains 10 percentage respectively, 7 percentage difference between the anti-knocking ability of 3 percent of n-heptane. So the octane level of gasoline engines has become the ability to knock against the level indicator.
1. The reference fuel noun
The so-called No. 90, No. 93, No. 97 unleaded gasoline, they contained 90 refers to the percentage, the percentage of 93, 97 percentage of the anti-knocking ability strong “isooctane”, that is to say each containing 10 percentage difference in the percentage of 7, the anti-knocking ability of 3 percent of n-heptane. So the octane level of gasoline engines has become the ability to knock against the level indicator.
In the automotive engine design phase, than the reference fuel used is set according to the compression. The compression ratio is a very important structural parameter of the engine which represents the volume of gas than the gas at the start of the volume of the piston at the end of the compression top dead center of a compression bottom dead center of the piston. From the power and economy, the compression ratioIt should be the bigger the better. Compression ratio, power, high thermal efficiency, vehicle acceleration, maximum speed, etc. will be increased. But restricted by the material properties of the cylinder and the combustion knock gasoline, gasoline engine compression ratio can not be too large. Simply put, a higher compression ratio can be used fuel transportation label. The higher grade fuel, the slower combustion rate of oil, the lower the combustion knock, the engine requires a higher compression ratio.
also to the reference fuel engine ignition timing problem. Low grade gasoline burning speed, ignition lag angle, high-grade and vice versa. For example, an engine according to the specification in claim 93 should be added to gasoline, gasoline is now added to the 90, timing light required, the ignition advance angle hysteresis once to twice. If you do not follow the recommendations OEMs, the use of low grade fuel, without adjusting the ignition timing, may cause difficulty in starting the engine; acceleration, collision with a crisp metallic sound in the engine; the long-distance traffic, the engine shake off an ignition switch or do not stop running. Compression based primarily on the grade of gasoline or selected ratio of the engine.
2. Gasoline selection principles
● The selection gasoline automobile manufacturers specified.
● The gasoline engine compression ratio selection.
● The automotive gasoline selected conditions.
3. The standard fuel oil drop and excessive oil
93 oil 5 oil expensive than the percentage of 90, but about 5 percentage consumption is small, fuel consumption than 100 kilometers from the amount of money theoretically equal. But considering the 93 high compression ratio of the engine oil match with 90 oil when the secondary combustion and incomplete combustion phenomenon occurs, the extra 5 percentage -8 percentage of power loss, then consider increasing maintenance costs caused by vehicles, condition decline , reducing life expectancy and a series of consequences, lowering the cost of oil standard on the go.
is a highly volatile liquid gasoline, minus 30 degrees Celsius when the combustible components are still volatilized, when low grade of gasoline, oil and gas will be compressed mixed before ignition in auto-ignition, ignition, spontaneous combustion of oil and gas has started in turn produced a strong explosion, the combustion process was originally designed precisely out of control, some gasoline negative work done, in part because the combustion process is not synchronized with the piston stroke is not completely burned, causing the intake valve cylinder and a serious coke, increased fuel consumption, exhaust bad. When the car at high speed, the confusion of the combustion process will produce a continuous knocking, it will seriously damage the engine, causing the spark plug insulation break, electrode excessive burning, piston knock, stuck piston rings, valve ablation and other consequences. This “crazy” transmission mode, the drive to make their way to the car to work in the “high rock” state, the consequences can be imagined.
In recent years, 97 # gasoline began to appear widely in the domestic market. Some riders use of gasoline also fell into a misunderstanding, it is keen to use high-grade gasoline. Even some riders to grade gasoline as a fuel purity and quality standards. This is wrong. In fact, the level of gasoline label only indicates the size of the gasoline octane number, label must not be confused with the purity and quality. 93 oil engines insist on using 97 oil will be “ignition delay” phenomenon, that it is less than head down to the point of spontaneous combustion with, it would appear incomplete combustionphenomenon.
4. Antiknock fuel knock and
is generally believed that, when the piston is at about 10 degrees after top dead center of the stroke, the maximum combustion pressure, maximum efforts to promote the piston (to like swing, swing a little hard after reaching the highest point of the fastest). For example, 1000 rpm when the combustion process is equivalent to the crank angle of 20 degrees, 10 degrees, that is pre-ignition engine, the most powerful. And to 4000 rpm, the faster movement of the piston, the combustion process is equivalent to a crank angle of 60 degrees, 50 degrees requires pre-ignition, so the speed increases, the ignition advance is increasing. Will eventually reach a speed, not oil and gas ignition to burn up, this is the knock.
grade gasoline determines the detonation point sooner or later, in fact, is the power determines the size of the engine. Fuel anti-knock performance over its composition varies. The higher fuel anti-knock properties, may also be some high compression ratio of the engine, the engine of the economy and dynamics will be improved.
determining the fuel knock resistance is difficult, because the fuel knock resistance depends not only on the nature of the fuel, but also with the type of the engine, air-fuel ratio, cooling water temperature, intake air temperature, spark advance angle, valve timing and the like.
5. Basic introduction to the country to promote the country’s gasoline V
From at 0:01 on July 2014 day oil wholesale companies and gas stations in most cities in Guangdong Province all countries Ⅴ standard vehicle sales gasoline. Ⅴ country gas station must be completed before June 30 car in updating gasoline replacement and logo. Gas stations and wholesale oil companies should bear “(Ⅴ)” after the word identification purchase and sale invoices and bills of lading and other commodity gasoline. More intuitive that after upgrading gasoline V numeral country from the original 90, No. 93, No. 97 to No. 89, No. 92, No. 95, and add 98 gasoline GB. New reference numerals with the same reference numerals Euro V gasoline.
For Experts said country V gasoline is adjusted for the original oil, by which the 92 gasoline suitable for original use 93 gasoline vehicle, gasoline 95 is suitable for the original use of 97 gasoline the vehicle owner may be an oil fuel in a corresponding number. It is understood that, based on the experimental results of the China Automobile Research Center, the original use 93 oil vehicle after switching to No. 92 oil consumption is closer to no significant change. Fuel economy is the result of the combined effects of vehicle and fuel economy of gasoline octane numbers of representatives and vehicles used no obvious direct relevance. Octane gasoline vehicle as long as the selected basic design octane match, will not cause significant impact on fuel consumption.