Lubricating Oil Composition for Deposit Control in High Load Engines

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Solution Overview

Problem

Steel piston engines operating under sustained high load conditions form excessive deposits, leading to shorter component life when using conventional lubricant additive packages with heavy neutral base oils, which fail to provide adequate deposit control.

Innovation Solution

A lubricating oil composition comprising a blend of Group I, II, and III base stocks with specific kinematic viscosities, where the weight ratio of a high viscosity base oil component to a low viscosity base oil component ranges from 1:10 to 1:1.15, providing improved resistance to deposit formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If heavy neutral base oil (API group base oil with highest viscosity cut) is used to achieve desired oil life characteristics, then oil life is improved, but excessive deposits form on mechanical components leading to shorter component life

Engineering Contradiction:
Improveoil lifeVSAvoiddeposit formation
Core Design Contradiction:
Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent changes the viscosity parameter of the base oil by using a lighter neutral base stock with kinematic viscosity at 100°C of 2.0 to 8.0 mm²/s instead of the conventional heavy neutral base oil with higher viscosity. This parameter change reduces deposit formation while maintaining adequate oil life through the synergistic additive package.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite lubricant formulation by combining lighter base stock with a synergistic package of additives including detergent, dispersant, and antiwear agents. This composite approach balances the competing requirements of oil life and deposit control that cannot be achieved with heavy base oil alone.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If conventional lubricant additive packages with heavy neutral base oil are used, then oil life characteristics are achieved, but deposit control capacity is insufficient

Engineering Contradiction:
Improveoil life characteristicsVSAvoiddeposit control capacity
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent changes multiple parameters simultaneously: base oil viscosity (from heavy to lighter stock), detergent concentration (0.5-5 wt%), dispersant concentration (0.5-5 wt%), and antiwear agent concentration (0.1-1.0 wt%). This multi-parameter optimization achieves both adequate oil life and improved deposit control capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a composite additive package where detergent, dispersant, and antiwear agents work synergistically with the lighter base stock. This composite formulation provides balanced performance for both oil life and deposit control, resolving the reliability issue with conventional packages.

Inventive Principle:
Principle #40Composite materials

3Strength

If steel pistons are used to maintain strength under higher pressures and temperatures, then piston strength is improved, but excessive deposits form on pistons and other mechanical components

Engineering Contradiction:
Improvepiston strengthVSAvoiddeposit formation on components
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the lubricant viscosity parameter to match the operating conditions of steel piston engines. The lighter base stock with kinematic viscosity of 2.0 to 8.0 mm²/s at 100°C provides better flow characteristics and deposit control while still maintaining adequate film strength for steel piston applications operating at BMEP > 20 bar.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using lighter base stock specifically tailored for steel piston engine conditions (high pressure, high temperature, sustained load). The additive package is locally optimized with specific concentrations of detergent, dispersant, and antiwear agents to address the specific deposit control needs of steel piston engines while maintaining overall lubrication performance.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3645688B1Lubricating oil composition
Publication Date: 2022.06.22 CHEVRON ORONITE CO LLC

AI summary

A lubricating oil composition with enhanced deposit control capability is disclosed for engines operating under sustained high load conditions, such as natural gas engines and low-speed or medium-speed diesel engines. The composition comprises (a) a first base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100oC of from 8.5 to 15 mm2/s; and (b) a second base oil component selected from a Group I base stock, a Group II base stock, a Group III base stock, or a combination thereof, each having a kinematic viscosity at 100oC of from 4.0 to less than 8.5 mm2/s; wherein the weight ratio of the first base oil component to the second base oil component is in a range of from 1:10 to 1:1.15.