The octane number is an indicator of detonation firmness of automobile gasoline and other motor fuel. It is considered to be that the it is higher than an octane number, the this fuel has the best qualities, so, it will significantly affect operation of the engine. But quite often there is a need to reduce octane number of the used motor fuel.
It is required to you
- - odnoporshnevy engine;
- - portable device for determination of octane number;
- - gasoline with low octane number;
- - sulphurous connections.
Instruction
1. Before considering ways of reduction of octane number, get acquainted with features of this indicator and ways of determination of octane number. A reference mark in an octanew scale – detonation stability of heptane (octanew the indicator is equal to 0).
2. For 100 accept octane number of an izookatan. Gasoline which octane number needs to be reduced also consists of these two substances (heptane and isooctane). So, the octane number of AI-92 gasoline indicates that this combustible fuel has the same detonation stability as mix of 92% of isooctane and 8% of heptane.
3. To define octane number, motor fuel is compared with reference, consisting of isooctane and heptane. Distinguish the following methods of determination of octane number: research, chromatographic, motor and by means of special portable devices.
4. The motor method of definition of an indicator of detonation stability of fuel means imitation of intense driving with use at the same time of the one-piston engine. However this method is imperfect: the indicator received this way can be a little underestimated.
5. The research method means use of the one-piston engine too (without driving imitation): this way of determination of octane number can yield the overestimated result.
6. The chromatographic method is used as the additional method intended for identification of various impurity in fuel, for example, of benzene. However the most reliable way of definition of an indicator of detonation stability of fuel – measurement of octane number special portable devices.
7. Knowing an indicator of detonation stability of combustible fuel, it is possible to bring it to the necessary result including to reduce. One of ways to reduce octane number – to add to high-octane fuel gasoline with a smaller indicator of detonation stability.
8. The octane number can be lowered if to add to combustible fuel with a high rate of detonation stability sulphurous connections. Besides, low octane number at gasoline after primary distillation of oil: this indicator does not exceed 70.
9. Besides the indicator of detonation stability decreases also without intervention of the person − at long storage of fuel: in a day the octane number can decrease by 0.5.