Hydrocracking is one of the fastest growing divisions in oil processing. Over the past 20 years hydrocracking capacities in the world increased 4 times and reached nearly 250 million. m3 feedstock per year. The process allows by way of selecting suitable catalysts and process parameters to obtain a high yield of the oil components which have a high viscosity index and possess antioxidant resistance. In hydrocracking compounds of sulfur, nitrogen and other compositions are removed. At the same time the processes of hydrogenation of polycyclicaromatics, the splitting of naphthenic rings, destruction of long paraffin chains and product isomerization take place.
In other words, hydrocracking is a process of mineral base oils modification which allows to get the feedstock similar in quality to synthetic base oils.
The difference is in the additives package. It should be noted that most of the modern engine oils are made so that they can be used both in gas and diesel engines. The oils which are used only in diesel engines are applicable as a rule only in commercial vehicles. In choosing the oil type pay attention to API index the first letter of which refers to the operation field: S-service (oils for gas engines), C-commercial (oils for commercial vehicles).
This question is directly connected to what engine oil you use. It is important to look after that the oil which you use should have the appropriate viscosity index.
Now let’s consider this question from two standpoints.
Technically
Technically, warming up is necessary. It enables engine oil to acquire its operational characteristics which in its turn ensures proper work of the engine.
Ecologically
At the time of warming the engine the amount of toxic volatile compounds is quite essential which damages the environment. It is caused by the fact that at the cold start the concentrated fuel mixture gets in the combustions chamber which increases the amount of combustion products while the catalyst which neutralizes toxic emissions is effective only after the normal operation temperature is reached which takes a while.
Proceeding from the above we cannot come to a certain conclusion in this question.
So, it’s up to you to decide whether to warm the engine or not before driving with an account of your personal civic stance.
Above all, we should clear up what we mean by the word “different”.
If you speak about oil type (mineral/semisynthetic/synthetic), then you certainly should not mix them. These oils are different by their manufacture method, have absolutely different characteristics and therefore should not be mixed.
If you speak about oil characteristics then you should at least add an oil having the same viscosity index (SAE) and performance (API) degree.
Example: If you use engine oil SAE 10W-40 and API SL/CF then the oil that you add must have exactly the same indices!
All the engine oils which are present on the market already have the additives package which is designed to help the engine oil to perform best its functions. The higher the operating characteristics of an engine oil (API degree) the higher the quality of an additive package is and hence the quality of the oil itself.
The use of additives is justified only in case when the positive effect from its use by far outweighs the damage which this additive may incur to an engine.
For example, a viscosity additive put to an engine with low compression may well help you cover thousand miles more before your engine needs to be overhauled. At the expense of oil thickening the gaps between cylinder block and pistons are shrunk, as a result the compression goes up, the oil does not get into combustion chamber, the plentiful smoke discharge from combustion pipe is stopped.
Synthetic engine oil has the following advantages:
lower solidification temperature. As a result the oils remains fluid at low temperature as compared to mineral oil which makes cold start easier in cold weather;
it reaches more easily and quickly remote parts of engine;
low evaporation degree enables to preserve oil characteristics at high temperatures;
synthetic oils enable the engine to be more efficient as compared to mineral oils (dynamometer tests) even at similar viscosity indices;
meet the latest engine requirements.
We shall not go into details of revealing all the peculiarities of oil manufacture as this does not in the least affect the buyer’s choice. Instead, we shall dwell on advantages and flaws of each of the above-mentioned oils.
Synthetic oil:
Advantages
- Is not subject to decomposition at high temperatures
- Excellent operation at low temperature
- Fewer impurities
Flaws
- More expensive as compared to semisynthetic and mineral oils
- Not suitable for older engines
Semisynthetic oil:
Advantages
- Best price/quality ratio
- Better characteristics than mineral oil
Flaws
- Operating characteristics are worse than those of fully synthetic oils.
Mineral oil:
Advantages
- Moderate price Despite its low price it functions well.
Flaws
- It is subject to decomposition and viscosity change (it becomes less viscous).
The correct oil change interval is specified in the service book of your car. The average interval of engine oil change of a car is 10,000 kilometers (from 8,000 to 15,000 km). There are engine oils, which are changed once per 30,000-40,000 kilometers. Oils of this class are generally used in the engines of modern commercial vehicles. As for the oil change in engines of agricultural and construction equipment, the crucial here is not the mileage- but hour-based maintenance (since the above machines operate without being moved or at low speed). Modern oils can be changed once in 200-500 operating hours.
The modern market offers consumers many sorts of oils under a variety of trademarks which are more or less recognized. Unfortunately, as is the case on other highly competitive markets, the buyer is often confronted with counterfeiting. Mostly, well-established brands are forged which urges manufacturers to regularly update the protection of their brands from counterfeiting. One of the easiest ways to protect yourself from buying fakes, is to purchase products from reliable suppliers.