Lubricant Composition for LSPI Prevention in Gasoline Engines

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Solution Overview

Problem

Gasoline engines with direct injection superchargers face the challenge of low-speed pre-ignition (LSPI), where the increased detergency from calcium detergents leads to heat generation and abnormal combustion, necessitating a balance between detergency and LSPI prevention.

Innovation Solution

A lubricating oil composition comprising a base oil, calcium detergent, magnesium detergent/sodium detergent, and boron-containing succinimide, with specific ratios and content levels to optimize detergency and LSPI prevention, including a poly(meth)acrylate and comb-shaped polymer for viscosity improvement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If calcium detergent content is increased to improve detergency, then cleaning performance is improved, but heat generation increases causing LSPI (low speed pre-ignition)

Engineering Contradiction:

ImprovedetergencyVSAvoidheat generation leading to LSPI

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing boron-containing succinimide and adjusting the ratio of calcium to magnesium/sodium detergents. This modifies the lubricant's properties to reduce heat generation while maintaining detergency, directly resolving the contradiction between cleaning performance and heat-induced LSPI

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite detergent system combining calcium detergent with magnesium detergent and boron-containing succinimide. This composite approach allows the mixture to achieve both excellent detergency and reduced LSPI tendency, as the components work synergistically to balance cleaning performance with heat generation control

Inventive Principle:

Principle #40Composite materials

2Reliability

If lubricant composition is optimized for detergency, then cleaning performance is improved, but fuel consumption increases

Engineering Contradiction:

ImprovedetergencyVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the chemical composition parameters including boron content (50-500 ppm), nitrogen content (0.01-0.15 mass%), and detergent ratios to achieve a balance where adequate detergency is maintained while minimizing fuel consumption through reduced viscosity modifiers and optimized additive package

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3505607B1Use of a lubricant composition in a gasoline engine

Publication Date: 2024.05.22 IDEMITSU KOSAN CO LTD

AI summary

Provided is a lubricating oil composition having excellent detergency and LSPI preventing performance, and specifically a lubricating oil composition including a base oil, a calcium detergent, and a magnesium detergent and/or a sodium detergent, wherein the content of the calcium detergent as converted into a calcium atom and a mass ratio of a magnesium atom (Mg) contained in the magnesium detergent and/or a sodium atom (Na) contained in the sodium detergent to a calcium atom (Ca) [(Mg and/or Na)/Ca] fall within the specific ranges.