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Frictional analysis on engine lubricant dilution by coconut oil and soybean oil derived biodiesel

Frictional analysis on engine lubricant dilution by coconut oil and soybean oil derived biodiesel
Engine Lubricant
Summary
This study investigates the tribological (frictional) behavior of engine lubricants diluted with biodiesel derived from coconut oil (CME) and soybean oil (SME). As concerns grow over fossil fuel depletion and greenhouse gas emissions, biodiesel is explored as a renewable, lower-emission alternative. However, its use in compression ignition engines can lead to lubricant dilution, potentially impacting engine wear and efficiency.

Using a pin-on-disc friction tester, the authors measured friction forces in SAE10W40 engine lubricant mixed with various concentrations (10–90% vol) of CME and SME biodiesels. The results showed that any level of biodiesel dilution increased friction compared to the undiluted lubricant, potentially reducing the effectiveness of the lubricant and increasing wear risks.

Use as a Green Chemistry Teaching Resource:
This article provides an excellent applied case study to illustrate multiple green chemistry principles in action. It can be used in undergraduate or graduate chemistry, engineering, or environmental science courses to:

Teach Principle #1 (Prevention): Highlight how proactive testing of biodiesel blends helps prevent unintended consequences such as engine damage due to lubricant dilution.

Explore Principle #7 (Use of Renewable Feedstocks): Demonstrate the use of plant-derived oils (coconut and soybean) as sustainable feedstocks for biodiesel production.

Apply Principle #9 (Catalysis): Discuss the role of the transesterification process and potential catalysts used in biodiesel synthesis.

Analyze Principle #10 (Design for Degradation): Open discussion on the environmental degradation pathways of biodiesel vs. petroleum diesel.

Teaching Formats:

Lab-to-classroom connection: Students can replicate simplified friction or viscosity tests using alternative fluids.

Green chemistry impact analysis: Students evaluate the lifecycle and environmental trade-offs of biodiesel vs. petro-diesel.

Case-based discussion: Facilitators can use this article to promote critical thinking around fuel formulation, engine design, and sustainability.

This resource supports interdisciplinary learning across green chemistry, mechanical engineering, and sustainable energy systems.

Full citation of journal article: Hamdan et al. (2018). Frictional analysis on engine lubricant dilution by coconut oil and soybean oil derived biodiesel. Jurnal Tribologi 18, pp.149-158.
Learning Goals/Student Objectives
By the end of this lesson or activity, students will be able to:

1. Explain the role of biodiesel as a renewable alternative to petroleum-based fuels, including its environmental benefits and challenges related to engine performance and maintenance.

2. Describe the tribological (frictional) properties of lubricants and analyze how biodiesel dilution impacts these properties using concepts like the Stribeck curve and lubrication regimes (hydrodynamic, mixed, and boundary).

3. Interpret experimental data from tribological testing (e.g., pin-on-disc friction tests) to draw conclusions about material behavior under different conditions.

4. Connect chemical structure to physical properties by analyzing how different fatty acid methyl ester (FAME) compositions in soybean and coconut biodiesels affect viscosity and friction.

5. Apply Green Chemistry principles—particularly renewable feedstocks, safer chemicals, and energy efficiency—to evaluate biodiesel’s role in sustainable fuel systems.

6. Identify trade-offs in sustainable engineering solutions, recognizing that renewable materials like biodiesel can have unintended performance impacts (e.g., increased friction or wear) that must be addressed through thoughtful design.

7. Collaborate to evaluate real-world data and propose strategies to optimize lubricant formulation or engine maintenance for systems running on biodiesel blends.

8. Align scientific inquiry with NGSS science and engineering practices, including designing investigations, analyzing data, and constructing evidence-based explanations.

Object Type
Case studies
Journal articles
Audience
Upper/Advanced Undergraduate
Common pedagogies covered
Blended learning
Collaborative/cooperative learning
Green Chemistry Principles
Waste Prevention
Safer Solvents and Auxiliaries
Use of Renewable Feedstocks
Catalysis
Design for Degradation
U.N. Sustainable Development Goals (SDGs)
Quality Education
Affordable and Clean Energy
Industry, Innovation and Infrastructure
Responsible Consumption and Production
Climate Action
Safety Precautions, Hazards, and Risk Assessment
Safety Precautions and Risk Assessment
Chemical Handling (Biodiesel & Engine Oil):
-Biodiesel, especially if synthesized via transesterification, may involve hazardous reagents like methanol, sodium hydroxide (NaOH), or potassium hydroxide (KOH). These are corrosive and toxic; proper PPE (gloves, goggles, lab coats) must be worn.
-Engine lubricants can contain additives that are irritating to the skin and eyes. Avoid prolonged contact and use in well-ventilated areas.

Fire and Flammability Risks:
-Biodiesel and petrochemical fuels are flammable liquids. Keep all flammable substances away from ignition sources. Use flame-resistant lab surfaces and store materials in certified flammables cabinets.
-Mechanical Testing Equipment (Pin-on-Disc Tribometer):
-Tribometers involve rotating components and applied force, posing a pinch or entanglement hazard. Keep hands and loose clothing away from moving parts.
-Ensure equipment is properly shielded and operated only under supervision by trained personnel.

Waste Disposal:
-Dispose of waste biodiesel, oils, and contaminated materials according to institutional hazardous waste protocols.
-Do not pour any used lubricants or oils down the drain.
-Ventilation and Fume Management:
-Reactions and tribology testing may release vapors or particulates. Conduct all experiments in a fume hood or ensure appropriate local exhaust ventilation is available.
-Risk Assessment and Emergency Response:
-Perform a risk assessment prior to any experiment involving fuels, solvents, or moving machinery.
-Keep spill kits, fire extinguishers, and eyewash stations nearby. All participants should be briefed on emergency procedures.
NGSS Standards, if applicable
High School – Physical Science (HS-PS):
HS-PS1-3
Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.
→ Students can analyze how molecular structure (e.g., fatty acid esters in biodiesel) affects viscosity and lubrication performance.

HS-PS1-5
Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
→ Relevant to understanding how biodiesel composition and concentration affect friction and wear, particularly during dilution.

HS-PS3-3
Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
→ Students can explore biodiesel’s role in engine efficiency and the energy transformation in fuel combustion systems.

High School – Engineering Design (HS-ETS):
HS-ETS1-3
Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints...
→ Students can assess the trade-offs of using biodiesel (renewable, lower emissions) versus increased lubricant wear (maintenance and environmental costs).

HS-ETS1-4
Use a computer simulation to model the impact of proposed solutions to a complex real-world problem...
→ Teachers can incorporate simulations of lubricant performance or friction testing to model environmental or mechanical impact.

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