Lubricating Oil Composition for Hybrid Engine Moisture Management

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Solution Overview

Problem

In hybrid electric vehicles, particularly parallel-hybrid electric vehicles, the frequent start-and-stop operation of internal combustion engines leads to inadequate engine oil temperature, causing moisture condensation and accumulation, which degrades the low-temperature fluidity of engine oil, resulting in reduced fuel efficiency.

Innovation Solution

A lubricating oil composition comprising a mineral or synthetic base oil with specific kinematic viscosity, metal salicylate detergent, comb-shaped poly(meth)acrylate, and succinimide dispersant, designed to maintain low-temperature fluidity and prevent degradation when contaminated with water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the internal combustion engine operates frequently at low rotational speed in hybrid electric vehicles, then fuel efficiency is improved through hybrid operation, but the engine oil temperature remains insufficient causing moisture condensation and accumulation

Engineering Contradiction:

Improvefuel efficiencyVSAvoidengine oil temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent converts the harmful effect of moisture condensation into a beneficial one by adding specific additives (comb-shaped poly(meth)acrylate and succinimide dispersant) that prevent moisture accumulation and maintain oil fluidity. The low-temperature operation that causes condensation is transformed into an acceptable condition through chemical modification of the oil composition.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical parameters of the engine oil by incorporating specific additives with defined molecular weights and concentrations. The comb-shaped poly(meth)acrylate with weight average molecular weight of 350,000 to 1,000,000 and succinimide dispersant modify the oil's physical-chemical properties to resist moisture accumulation and maintain fluidity at low temperatures.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If moisture accumulates in the engine oil due to insufficient temperature, then the low-temperature fluidity of the oil is degraded, but adding conventional additives cannot sufficiently prevent this degradation

Engineering Contradiction:

Improvelow-temperature fluidityVSAvoidmoisture condensation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces comb-shaped poly(meth)acrylate and succinimide dispersant as intermediary substances that mediate between the moisture and the base oil. These additives form protective structures that prevent water molecules from accumulating and degrading the oil's fluidity, acting as a buffer between the harmful moisture and the oil matrix.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite lubricating oil system by combining the base oil with specific additives (comb-shaped poly(meth)acrylate and succinimide dispersant) in defined proportions. This composite formulation leverages the complementary properties of each component to achieve superior moisture resistance and low-temperature fluidity compared to conventional single-additive formulations.

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If the low-temperature viscosity of the engine oil increases due to moisture contamination, then the stirring resistance increases and fuel efficiency deteriorates, but conventional lubricating oils cannot maintain optimal viscosity

Engineering Contradiction:

Improvefuel efficiencyVSAvoidviscosity stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback mechanism through the succinimide dispersant that monitors and responds to moisture contamination levels. The dispersant dynamically adjusts its action to maintain viscosity stability, preventing the harmful feedback loop where moisture accumulation would normally cause viscosity increase and reduced fuel efficiency.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11732207B2Lubricating oil composition for internal combustion engine

Publication Date: 2023.08.22 ENEOS CORP

AI summary

A lubricating oil composition for an internal combustion engine has a HTHS viscosity at 150° C. of 2.55-2.84 mPa·s and includes: (A) a lubricating base oil including (a) mineral base oil(s) and/or (a) synthetic base oil(s), and having a kinematic viscosity at 100° C. of 3.8-4.6 mm2/s; (B) 1000-2000 mass ppm, in terms of metal content, of a metallic detergent including (a) metal salicylate detergent(s), and delivering ≥10 mmol/kg of total salicylate soap base per kilogram of the composition; (C) 1.0 to 4.0 mass % of a comb-shaped poly(meth)acrylate having a Mw of 350,000-1,000,000 and a PDI of ≤4.0; and (D) 100-1000 mass ppm, in terms of nitrogen, of a succinimide dispersant including (i) (a) non-modified succinimide dispersant(s) and/or (ii) (a) boric acid-modified succinimide dispersant(s), wherein the (i) and the (ii), in total, deliver ≥70 mass % of total nitrogen content of the component (D).