In determining engine oil quality, several tests are to be carried out and several engine oil properties are to be put into consideration.
Engine and Bench Tests
The ultimate platform for the identification of the required quality of an oil ha been the engine. There has been a change in engine design to meet performance, fuel efficiency and environmental standards but though this, the engine continues to be the ultimate arbiter of oil quality.
However, it would too expensive a proposition using the engine to measure oil quality in dynamometer tests. Even so, in order to help control warranty costs, the development and use of engine tests is unavoidable for engine manufacturers when the determination of the oil quality needed for a particular design or component is the case.
The usage of a dynamometer for carrying out repeatable tests for an engine though necessary, can be challenging. This is the case because progressively increased power from smaller engine.
Fortunate enough, once the determination of the quality level has ben carried out using the dynamometer or in the field, there can be a more precise appraisal of the oil quality which is a much less expensive approach that can be applied.
This involves the usage of laboratory bench tests designed for the close correlation with engine dynamometer tests or field experience. These bench tests are capable of providing a relatively cheap measure of oil quality.
Nevertheless, the value and significance of this type of test is dependent on some factors which include identification of the engine’s specific needs, clear and consistent information from the engine either in dynamometer tests or field experience, and an understanding of the relationship between the engine’s needs and the oil’s physical and/or chemical properties.
Engine Oil Properties
Certain physical and chemical properties must be possessed by oil in order to serve the engine.
A number of operating stress is generated by the engine during the oil service and this makes for much adverse effect to the long-term ability of the oil to function at a consistently high level. Service conditions may also have a wide variation depending on the environment and the way the vehicle is used. Consequent upon this, knowledge of several important oil properties, including viscosity is required in choosing an engine oil to meet particular service needs and conditions
Viscosity
In determining engine oil quality, viscosity is a very important oil quality. Viscosity may be defined as a fluid’s resistance to flow. Because a fluid’s molecules are somewhat attracted to one another, energy is required to pull them apart and create flow. Generally, larger molecules have more attraction between them and a higher viscosity.
The energy required to overcome this molecule-to-molecule attraction and produce fluid flow can be referred to as a form of friction.
Therefore, viscosity can be defined as a form of molecular friction. It is worthy of note that the most important engine oil’s physical and chemical qualities are its viscosity and viscometric behavior during use.
Viscosity and Wear Prevention
When there is the existence of pressure between two engine surfaces that are brought closely together and in relative motion, viscosity (molecular friction), prevents the oil from escaping too quickly.
This restriction from a quick escape of the intervening oil and its level of incompressibility hold the two surfaces apart and prevent wear, a process that is termed hydrodynamic lubrication.
The more viscous a liquid is, the greater the attraction that exists between the molecules of the oil and the greater the wear protection. This is why it is needful to use synthetic engine oil as it has higher viscosity and guess what, CDN oil is synthetic!
Viscosity Classification
There has always been the association of a lubricant’s viscosity with wear protection. Early in its history, viscosity was recognized by SAE as relevant to engine function and instituted the J300 classification system, which establishes viscosity levels for engines by a grading system.
These grades are defined by viscosity levels in one or two temperature zones. Presently, the grades are set for engine operating temperatures and for winter temperatures at which the oil affects starting and pumping.
Viscosity at Operating Conditions
In the early years of automotive engines, oils were simply formulated and were in consonance with Newton’s equation for viscosity – the more force used to make the fluid flow (shear stress), the faster it the flow of the fluid (shear rate).
Essentially, the ratio of shear stress to shear rate – the viscosity – remained constant at all shear rates. The engine oils of that time were all essentially single grade and carried no SAE “W” classification.
High Shear Rate Viscometry
Consequently, there arose the need to develop a high shear rate viscometer for the reflection of the viscosity in engines under operating temperatures which was called the tapered bearing simulator viscometer.
This viscometer is unique and basically absolute in the provision of measures of both shearing torque or shear stress and shear rate while operating and is the only known viscometer capable of doing this.
Viscosity and Oil Gelation at Low Temperatures
Multigrade engine oils were originally introduced for the purpose of reducing oil viscosity at low temperatures to aid in engine startup. This important benefit was immediately apparent, and multigrade oils have since become the most popular form of engine lubricant around the world.
Gelation Index
The air-binding engine oil that was responsible for the Sioux Falls failures provided a solid case study. A new bench test instrument and technique were developed for the indication of any tendency of the test oil to gelate.
The technique involved continuous low-speed operation of a cylindrical rotor in a loosely surrounding stator and was immediately incorporated into engine oil specifications and later became ASTM D5133.
This showed the oil’s tendency to become flow-limited but beyond this, also specified the degree of gelation that has the possibility of occurring over the measured temperature range (typically minus 5 to minus 40 degrees C). The parameter was referred to as the gelation index. Today, engine oil specifications for multigrade oils require a maximum gelation index of 12.
This is to prove that in determining engine oil quality, the gelation index is one of the parameters to be considered.
Viscosity and Energy Absorption
The viscosity of an oil is very beneficial to engine as it helps in the prevention of wear through hydrodynamic lubrication but as much as it is beneficial, it also has some adverse aspects that can affect the engine’s operating efficiency.
Energy is required to overcome the oil’s molecular friction, which separates two surfaces in relative motion. This is a significant amount of energy from the engine in exchange for the provided wear protection. Therefore, careful formulation of the oil viscosity is very much important to vehicle owners and to governments mandating fuel economy limits.
Lowering oil viscosity can be a critical step in the reduction of viscous friction to make for improved fuel efficiency. This is to say that a good engine oil should have low viscosity.
Viscosity-dependent Fuel Efficiency Index
Consequent upon the influence that oil viscosity has on the engine, a technique was developed for the calculation of the effects of engine oils on fuel efficiency. In order to have a meaningful one, the viscosity values had to be obtained at the high shear rates associated with operation in specific sections of the engine and this is a necessary consideration in determining the engine oil quality.
Engine Oil Volatility
In determining engine oil quality, engine oil volatility id considered. Another aspect to consider when reducing the viscosity in engine oil formulations is that the use of base oils with higher volatility for this purpose makes for the most frequently obtained reduction. V
olatized oil brings about reduction in the amount of lubricant serving the engine and may carry exhaust catalyst-contaminating components, which has negative effects on the catalyst’s smog-reducing ability.
The oil remaining after the loss of the more volatile components will also have more viscosity and high energy absorption.
Phosphorus Emissions and Volatility
In determining engine oil quality, an engine oil will high quality if it contains soluble phosphorus compounds such as zinc dialkyldithiophosphate (ZDDP).
These soluble phosphorus compounds have been used in the formulation of engine oils for several years. These compounds are anti-wear and antioxidation compounds and have provided considerable support to the design of modern engines.
Conclusion
CDN Oil meets all of these requirements and many more; you are just a purchase away from enjoying the incredible benefits of CDN oil and lubricants.