Lubricating Oil Composition for Diesel Engine Preignition Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbocharged downsized engines and premix combustion engines experience preignition issues, which are exacerbated by engine oils, leading to energy loss and restrictions on fuel efficiency and torque, while reducing metallic detergents compromises detergency and acid-neutralization performance.
Innovation Solution
A lubricating oil composition with a specific integrated intensity ratio of CaO in X-ray diffraction spectra and a balanced molar ratio of boron to calcium, using calcium borate-containing detergents, suppresses preignition without deteriorating detergency or acid-neutralization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a lubricating oil with high viscosity index improvement is used to maintain film strength at high temperatures, then the kinematic viscosity at 100°C increases, but the oil becomes too thick for proper atomization and combustion in low-flash-point fuel engines
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricating oil by incorporating specific additives (calcium sulfonate complex 3-15 wt%, phosphorus-containing additive 1-5 wt%, nitrogen-containing additive 1-5 wt%) to achieve the desired balance between film strength and viscosity. This chemical parameter adjustment allows the oil to maintain appropriate viscosity at 100°C (12.0-16.0 mm²/s) while providing sufficient film strength for high MEP engines.
Solution Approach 2:
The patent uses a composite lubricating oil formulation combining multiple additive packages (calcium sulfonate complex, phosphorus-containing additive, nitrogen-containing additive) with base oil to create a composite material that achieves both high film strength and controlled viscosity. The synergistic interaction of these composite components resolves the contradiction between film strength and viscosity requirements.
2Reliability
If multi-functional additives are incorporated into the lubricating oil to enhance protective functions, then the ash content increases, but excessive ash forms harmful deposits in the combustion chamber
Solution Approach 1:
The patent precisely controls the concentration parameters of multi-functional additives to optimize protective function while minimizing ash deposits. The calcium sulfonate complex is limited to 3-15 wt%, phosphorus-containing additive to 1-5 wt%, and nitrogen-containing additive to 1-5 wt%. This parameter control ensures the integrated intensity ratio of CaO peaks in XRD spectrum remains at 16.5% or less, preventing harmful deposits while maintaining reliability.
Solution Approach 2:
The patent applies local quality by ensuring the additive package provides concentrated protective effects at critical friction surfaces (where film strength is needed) while maintaining low overall ash content for combustion chamber compatibility. The additive distribution and concentration are optimized locally at the tribological interface rather than uniformly throughout the oil.
3Strength
If the lubricating oil is designed for high MEP engines requiring strong film strength, then the viscosity at operating temperature must be high, but this causes poor atomization and incomplete combustion in engines using low-flash-point fuels
Solution Approach 1:
The patent changes the viscosity parameter at operating temperature by controlling the kinematic viscosity at 100°C to be 12.0-16.0 mm²/s and the viscosity index to be 110-130. This parameter optimization ensures the oil remains fluid enough for proper atomization and combustion efficiency while providing sufficient film strength for high MEP engines through additive enhancement rather than relying solely on high viscosity.
Solution Approach 2:
The patent introduces multi-functional additives as intermediary substances that mediate between the conflicting requirements of film strength and combustion efficiency. These additives (calcium sulfonate complex, phosphorus-containing additive, nitrogen-containing additive) act as intermediaries that enhance tribological performance without significantly increasing viscosity, thereby maintaining good atomization and combustion characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively suppresses preignition in engines with high mean effective pressure and low-flashpoint fuels, maintaining detergency and acid-neutralization performance even with a large magnesium detergent content.
Implementation Method 1
supplying a specific lubricating oil composition to a cylinder of an internal combustion engine... the lubricating oil composition has a kinematic viscosity at 100°C of 12.0 to 16.0 mm2/s; and a viscosity index of not less than 110
Implementation Method 2
the lubricating oil composition contains a detergent dispersant which is effective in preventing formation of deposits in a high temperature area of an internal combustion engine
Implementation Method 3
the lubricating oil composition contains a detergent dispersant which is effective in preventing formation of deposits
Data Source
Figure 1
Figure 2
AI summary
A method for lubricating an internal combustion engine, the method comprising: supplying a specific lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, the lubricating oil composition has a kinematic viscosity at 100°C of 13.0 to 16.3 mm2/s; and an integrated intensity ratio of peaks of CaO in an X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950°C; and the internal combustion engine is a premix combustion medium-speed trunk piston diesel engine using a first fuel as a main fuel, wherein the first fuel has a flash point of no more than 15°C.