How to see the oil test report Teach you how to understand the diesel test report
Understand oil inspection report 1:
We all know that the routine testing items of automotive gasoline and diesel are: density, distillation range, copper corrosion, thiol sulfur, vapor pressure, oxidation stability, benzene content, oxygen content, sulfur content, moisture and mechanical impurities, actual gum, carbon residue, octane number, cetane number, and diesel lubrication, polycyclic aromatic hydrocarbons detection and other items of inspection.
So, how to understand the quality of oil products when you get a "inspection report" that contains the efforts of the inspectors and indicates the inspection items and data? Below, we will answer the relevant questions about the oil inspection, especially the common items of vehicle gasoline and diesel inspection: the performance meaning of oil products
1. The distillation range of oil products refers to the temperature range of evaporation characteristics from the initial distillation point to the final distillation point obtained by distillation of oil products under specified conditions. Mainly used to determine the composition of light and heavy fractions of oil, control product quality and performance.
2, octane number - represents a conventional value of ignition engine fuel antiknock. In a standard engine test under specified conditions, it is determined by comparing it with a standard fuel. It is expressed as the percentage by volume of isooctane in a standard fuel with the same antiknock property as the measured fuel. Different methods of determining octane number will result in different values, so the method used should be specified when quoting octane number.
3, motor octane number - at a higher mixture temperature (generally heated to 149℃)
2 and the high engine speed (generally up to 900 RPM) of the harsh conditions for its characteristic experimental standard engine measured octane number.
4, research method octane number - the octane number measured by the experimental standard engine characterized by moderately harsh conditions of low mixture temperature (generally not heated) and low engine speed (generally up to 600 RPM).
5, saturated vapor pressure - is used to describe the size of the evaporation capacity of the oil and the possibility of the oil in the pipeline oil intake system to form a gas resistance and the tendency to lose light fractions during storage and transportation. The saturated vapor pressure of gasoline is large, the evaporation is large, the possibility of forming gas resistance is also large, and the evaporation loss is also large in storage and transportation.
6, flash point - refers to the minimum temperature of petroleum products under specified conditions, heated to its steam and flame contact instantaneous flash fire. The lighter the oil, the lower the flash point. The danger level of oil products is divided according to the flash point. The light and weight of oil composition can be judged from the flash point, and the risk of oil fire can be identified. The flash point measured by the closed flash point tester is called the closed flash point, which is generally used to determine light oil products. The higher the flash point, the safer.
7, Doctor test - in the presence of sublimed sulfur, with sodium lead acid and light petroleum products to check the oil of mercaptan or hydrogen sulfide test.
8, closed flash point - the flash point measured by the specified closed flash point tester, expressed in ° C.
9, open flash point - the flash point measured by the specified open flash point tester, expressed in ° C.
10, ignition point - under the specified conditions, when the flame is close to the oil and gas and air mixture on the surface of the oil, it will catch fire and continue to burn to the required low temperature for the specified time, expressed in ° C.
11, spontaneous ignition point - under the specified conditions, the oil in the absence of flame, spontaneous ignition temperature, expressed in ° C.
12, cetane number - represents a conventional value of diesel ignition performance in the engine. In a standard engine test under specified conditions, it is determined by comparing it with a standard fuel. It is expressed as a percentage by volume of the cetane number in a standard fuel with the same ignition lag as the measured fuel.
13. Cetane index - A calculated value indicating the ignition performance of diesel oil in an engine. This value is calculated from the standard density of diesel oil and 50% distillate temperature. It is generally used when there is no cetane check-in or when the sample is too small to perform standard engine tests.
14, freezing point - refers to the highest temperature when the oil is cooled to stop flowing under specified conditions. The freezing point is used to evaluate the low temperature performance of oil products.
23, What is corrosive?
Corrosive substances are not allowed in the oil. The method of identification is to immerse the brass sheet in the oil test tube, heat the test tube to 200-220 ° C to remove and cool, if the brass sheet has black spots or brown indicates that there are corrosive substances in the oil. Otherwise, no corrosive substance.
24, What is ash?
Substances that cannot volatilize and burn at high temperatures are called ash. The increase of ash in the oil increases the wear of the machine parts.
25, What is the cold filter point?
It is an important indicator to measure the low temperature performance of light diesel, specifically, the highest temperature at which diesel begins to block the engine filter under specified conditions. When the user selects the diesel brand, the specific value of the cold filter point should be used as a reference basis. The cold filter point of common diesel grades is as follows: the cold filter point of No. 5 light diesel is 8 ° C, the cold filter point of No. 0 light diesel is 4 ° C, the cold filter point of No. -10 light diesel is -5 ° C, and the cold filter point of No. -20 light diesel is -14 ° C. Therefore, diesel should be selected for the cold filter point corresponding to the local temperature and diesel brand at the same time, that is, No. 0 light diesel should be selected when the ambient temperature is 4 ° C, and No. -10 light diesel should be selected when the ambient temperature is -5 ° C, and so on.
26, What is the condensation point? It is an important index to measure the flow performance of light diesel oil at low temperature. Specifically, it is the highest temperature at which light diesel oil is cooled to stop moving under specified conditions.
The brand of light diesel oil corresponds to its freezing point, that is, the freezing point of No. 0 light diesel oil is 0 ° C, and the freezing point of No. -10 light diesel oil is -10 ° C, and so on.
27. What is distillation range? The distillation range is an indication of the amount and temperature that may be distilled from the petroleum product within a certain temperature range. The distillation range is an important index to ensure the rapid evaporation and combustion of diesel oil in the engine combustion chamber. Light diesel oil full distillation range 160~365℃; Heavy diesel used in low-speed diesel engines, there is sufficient atomization, evaporation time, the distillation range is not strict requirements, generally in the 250~450℃, the current in the medium and low-speed large and medium-sized diesel engines have begun to use mixed fuel oil.
28. What is density? Density is the simplest and most commonly used physical index of petroleum and its products. The density of natural crude oil (20 ° C) is about 0.7 to 1㎏/L. The density of oil containing more aromatic hydrocarbons, colloid and asphaltenes is the highest, the density of oil containing more naphthene is the middle, and the density of oil containing more paraffin (paraffin) is the least.
29, What is the freezing point? The freezing point is also called the freezing point, and the highest temperature when the oil does not flow is called the freezing point. The freezing point can be determined by placing the oil in a glass test tube and cooling it continuously until the test tube is tilted to 45° and the oil level can remain unchanged for 1min, which is the freezing point of this oil.
30, What is the pour point?
The pour point is the lowest temperature at which the petroleum product is cooled to the point where the liquid does not flow and then slowly warmed to the point at which it begins to flow under specified test instruments and conditions. The pour point of petroleum products containing more wax is higher, and the pour point can be reduced by gum and asphalt. A small amount of water will cause the pour point of low pour point oil to rise. The pour point is 1-3 ℃ higher than the freezing point.
31, What is the flash point?
32, the lowest temperature of combustible gas produced by oil is called the flash point. The lower the flash point, the more volatile the oil is. Flash point can be determined by the following method: the oil is injected into the crucible in the dark place, the crucible is heated, the oil is inserted into the thermometer, about 10 ° C before the flash point, the ignition material is ignited at 8-10mm on the oil surface, and the oil temperature at the moment is the flash point. What is the cetane number?
Cetane number is an indicator of the spontaneous combustion of diesel fuel when it is burned in a diesel engine. The cetane number of pure cetane is often set to 100, and the cetane number of pure α-methylnaphthalene is set to zero, and the standard fuel with cetane number 0 to 100 can be mixed in different proportions, and the standard fuel with different antiknock grades can be obtained, and the single cylinder test machine with a certain structure is compared with the diesel oil to be tested. 33, What is water?
The percentage of water content in the total weight of the oil is called moisture. The moisture in the oil not only rusts the metal surface, but also emulsifies the oil and deteriorates its lubrication. To determine whether the oil contains water, you can put a small amount of white powder crystal free copper sulfate into the oil, if the copper sulfate from white to blue, and precipitate at the bottom of the oil that the oil contains water.