Lesson Notes By Weeks and Term v3 - Senior Secondary 3
Lubrication system and its parts
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Lubrication system and its parts
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Subject: Automobile Parts Merchandising
Class: Senior Secondary 3
Term: 2nd Term
Week: 1
Theme: Automobile Parts
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Watch on YouTubeThis topic introduces learners to the crucial role of the lubrication system in an automobile engine. Understanding the components and function of this system is fundamental for anyone involved in automobile parts merchandising, as it directly impacts vehicle maintenance, operational efficiency, and the sales of related spare parts. Proper lubrication is vital for engine longevity and performance, directly influencing vehicle reliability, which is a significant concern for vehicle owners and commercial operators across Nigeria, from private car owners to haulage companies.
parts.
Parts Merchandising Relevance: Not a replaceable part; integral to the engine block.
However, blocked passages (due to sludge) can necessitate engine flushing or overhaul, leading to sales of cleaning additives or engine overhaul parts.
7. Oil Cooler (Optional): Function: Found in some high-performance or heavy-duty engines (e.g., trucks, commercial vehicles common in Nigeria), it uses engine coolant or air to reduce the temperature of the engine oil.
Parts Merchandising Relevance: Replaced if damaged (e.g., leaks) or clogged. Relevant for commercial vehicle spare parts businesses.
8. Dipstick: Function: A calibrated metal stick inserted into a tube leading to the oil pan, used by the owner to manually check the oil level.
Parts Merchandising Relevance: Can be replaced if broken, corroded, or lost.
9. Oil Pressure Switch/Sensor and Gauge: Function: The sensor monitors oil pressure and sends a signal to the dashboard gauge or warning light. The warning light illuminates if oil pressure drops below a safe level, indicating a potential problem.
Parts Merchandising Relevance: Common replacement items due to electrical failure or sensor malfunction, which can lead to false warnings or no warning at all.
1
0. PCV (Positive Crankcase Ventilation)
Valve: Function: Prevents the buildup of harmful unburnt gases (blow-by gases) and moisture in the crankcase by routing them back into the engine's intake manifold to be re-burned. This reduces emissions and prevents oil contamination.
Parts Merchandising Relevance: A small, inexpensive part that can significantly impact engine health if clogged. Regular replacement (as part of tune-up) is recommended. 2.
3. Types and Characteristics of Engine Oils (Lubricants): Viscosity: A measure of an oil's resistance to flow. Low viscosity oil flows easily (e.g., 5W-30), while high viscosity oil flows slowly (e.g., 20W-50). SAE (Society of Automotive Engineers)
Viscosity Grades: Monograde oils: e.g., SAE 30, SAE
4
0. Single viscosity rating, often used in older engines or specific industrial applications. Less common for modern passenger vehicles.
Multigrade oils: e.g., 10W-30, 20W-50. "W" stands for "Winter" and indicates the oil's viscosity at cold temperatures. The second number indicates viscosity at operating temperature (100°C). Multigrade oils provide good flow at cold start-up and maintain adequate viscosity at high operating temperatures, crucial for the diverse climates and stop-and-go traffic in Nigerian cities. API (American Petroleum Institute)
Service Ratings: 'S' Series (Spark Ignition Engines - Petrol): e.g., SN, SM, SL. The higher the second letter, the more recent and stringent the specifications (better protection, fuel economy, etc.). SN is current for modern petrol engines. 'C' Series (Compression Ignition Engines - Diesel): e.g., CJ-4, CI-
4. Similarly, higher letter indicates newer specifications.
Dual Ratings: Some oils have both (e.g., CI-4/SL) for use in both petrol and diesel engines.
Base Oil Types: Mineral Oil: Derived from crude petroleum, less refined. Cost-effective and suitable for older engines or those not requiring advanced protection. Widely available in Nigeria.
Synthetic Oil: Artificially engineered from chemical compounds. Offers superior performance, better temperature stability, extended drain intervals, and reduced engine wear. More expensive but beneficial for modern, high-performance engines and severe driving conditions common in Nigeria (heat, dust, traffic).
Semi-Synthetic (Synthetic Blend)
Oil: A mixture of mineral and synthetic oils, offering a balance of performance and cost. 2.
4. Working Principle of a Typical Lubrication System:
1. Oil Pickup: The oil pump, driven by the engine (usually by the crankshaft or camshaft), draws oil from the oil pan through the oil strainer.
2. Pressure Generation: The oil pump increases the oil's pressure.
3. Filtration: Pressurized oil is forced through the oil filter, which removes contaminants.
4. Distribution: Clean, pressurized oil flows through main oil galleries within the engine block and cylinder head.
5. Lubrication: From the main galleries, smaller passages branch off to lubricate critical moving parts: Crankshaft main bearings and connecting rod bearings. Camshaft bearings. Valve train components (lifters, pushrods, rocker arms, valves). * Piston pins and cylinder walls (splash or direct spray).
6. Return: After lubricating the parts, the oil, now heated and having picked up some contaminants, drains back down by gravity into the oil pan to complete the cycle. *Worked Example The lubrication system is an essential part of an internal combustion engine, designed to reduce friction, dissipate heat, clean internal components, seal gaps, and protect against corrosion. Without proper lubrication, an engine would seize up due to excessive heat and friction within minutes of operation. 2.
1. Functions of the Lubrication System: Reduce Friction: The primary role is to create a thin film of oil between moving metal parts (e.g., crankshaft and bearings, pistons and cylinder walls), preventing direct metal-to-metal contact and reducing wear.
Cooling: Lubricating oil absorbs heat generated by friction and combustion, carrying it away to the oil pan where it can dissipate. In some systems, an oil cooler further aids this process.
Cleaning: Oil helps to clean the engine by picking up microscopic wear particles, carbon deposits, and other contaminants, holding them in suspension until they are trapped by the oil filter.
Sealing: The oil film provides a seal between the piston rings and cylinder walls, preventing combustion gases from escaping into the crankcase (blow-by) and maintaining compression.
Noise Reduction: The oil film cushions the impact between moving parts, thereby reducing engine noise and vibration.
Corrosion Protection: Engine oil contains additives that coat metal surfaces, protecting them from rust and corrosion, especially important in humid Nigerian environments. 2.
2. Major Components of the Lubrication System and Their Functions:
1. Oil Pan (Sump): Function: Located at the bottom of the engine, it serves as a reservoir for engine oil when the engine is not running and collects oil as it drains from various engine parts.
Parts Merchandising Relevance: Often requires replacement due to damage from road debris (potholes are common in Nigeria), corrosion, or stripped drain plug threads. Gaskets or sealant are also frequently sold.
2. Oil Pump: Function: Circulates oil throughout the engine under pressure. It draws oil from the oil pan and sends it through the oil filter to the various lubrication points. Common types include gear pumps and rotor pumps.
Parts Merchandising Relevance: A critical component. Failure leads to catastrophic engine damage. Signs of failure (low oil pressure) prompt replacement.
3. Oil Strainer (Pickup Tube): Function: A mesh screen attached to the oil pump's intake pipe, submerged in the oil pan. It prevents large debris (e.g., metal shavings, sludge) from entering and damaging the oil pump.
Parts Merchandising Relevance: Not a frequent replacement item unless damaged during oil pan removal or engine overhaul.
However, if clogged by sludge, it must be cleaned or replaced.
4. Oil Filter: Function: Removes contaminants (dirt, metal particles, carbon) from the engine oil before it circulates through the engine's vital parts. This is crucial for maintaining oil cleanliness.
Parts Merchandising Relevance: A high-volume consumable item. Must be replaced at every oil change (typically 5,000 - 10,000 km, depending on oil type and driving conditions in Nigeria). Different vehicle models use specific filter types and sizes.
5. Pressure Relief Valve: Function: Integrated into the oil pump or oil filter housing, it regulates oil pressure. If pressure becomes too high (e.g., when the engine is cold and oil is thick, or at high RPMs), it opens to bypass some oil back to the oil pan or pump inlet, preventing damage to the system components.
Parts Merchandising Relevance: Usually part of the oil pump assembly or filter housing. Seldom sold separately unless a specific repair kit is available.
6. Oil Galleries/Passages: Function: A network of drilled passages within the engine block and cylinder head through which pressurized oil flows to lubricate bearings, camshafts, valve lifters, and other moving parts.
Parts Merchandising Relevance: Not a replaceable part; integral to the engine block.
However, blocked passages (due to sludge) can necessitate engine flushing or overhaul, leading to sales of cleaning additives or engine overhaul parts.
7. Oil Cooler (Optional): Function: Found in some high-performance or heavy-duty engines (e.g., trucks, commercial vehicles common in Nigeria), it uses engine coolant or air to reduce the temperature of the engine oil.
Parts Merchandising Relevance: Replaced if damaged (e.g., leaks) or clogged. Relevant for commercial vehicle spare parts businesses.
8. Dipstick: * Function: Distribution: Clean, pressurized oil flows through main oil galleries within the engine block and cylinder head.
5. Lubrication: From the main galleries, smaller passages branch off to lubricate critical moving parts: Crankshaft main bearings and connecting rod bearings. Camshaft bearings. Valve train components (lifters, pushrods, rocker arms, valves). Piston pins and cylinder walls (splash or direct spray).
6. Return: After lubricating the parts, the oil, now heated and having picked up some contaminants, drains back down by gravity into the oil pan to complete the cycle.
Worked Example (Nigerian Context): Selecting Engine Oil Scenario: A customer in Lagos owns a 2010 Toyota Corolla (petrol engine) and primarily uses it for daily commuting in heavy traffic. The manufacturer recommends 5W-30 or 10W-30 with an API SM rating or higher. The customer wants to save money but also wants good protection.
Analysis: Vehicle: 2010 Toyota Corolla (modern petrol engine).
Manufacturer Spec: 5W-30 or 10W-30, API SM or higher.
Driving Conditions: Heavy traffic (Lagos), implies high operating temperatures and frequent start-stops, which put stress on the engine and oil.
Customer Need: Cost-saving but good protection.
Solution Approach for a Merchandiser:
1. Identify suitable viscosity: Both 5W-30 and 10W-30 are acceptable. For a hotter climate like Nigeria and heavy traffic, 10W-30 might offer slightly better protection at high temperatures while still providing good cold start protection (though 5W-30 is technically superior for cold starts, which are less extreme in Nigeria). If the engine has high mileage, a slightly thicker oil within spec (e.g., 10W-40 if recommended as an alternative for high mileage) might be considered, but stick to manufacturer recommendations first.
2. Identify suitable API rating: The minimum is API SM. Current oils available are often SN or SP, which are backward compatible and offer superior protection.
3. Consider base oil type vs. cost: Mineral oil: Cheapest option. Might be suitable if the customer insists on lowest cost, but may require more frequent changes (e.g., 3,000-5,000 km) and offers less protection under severe conditions. Risk of sludge buildup in traffic.
Semi-synthetic: A good balance. Offers better protection than mineral, longer drain intervals (e.g., 7,000-8,000 km), and is moderately priced. This is often a popular choice in Nigeria for value-conscious drivers. * Full synthetic: Best protection, longest drain intervals (e.g., 10,000 km+), and ideal for heavy traffic and hot climates. Most expensive.
Recommendation to Customer: "Based on your Toyota Corolla's requirements and driving conditions in Lagos traffic, I recommend a 10W-30 or 5W-30 semi-synthetic engine oil with an API SN (or SP) rating. While a mineral oil is cheaper upfront, a semi-synthetic offers much better protection against engine wear and sludge formation, especially with the stop-and-go driving you experience. It will also allow you to go longer between oil changes, potentially saving you money in the long run on labour and oil filters. For instance, brands like Total Quartz, Mobil Super, or Castrol GTX often have suitable semi-synthetic options at competitive prices that meet these specifications." 3.
1. Teacher Activities: Introduction (10 minutes): Begin by asking students to recall the importance of vehicle maintenance. Engage students with questions like, "What would happen if your engine runs without oil?" (Answer: Engine seizure due to friction and heat).
This leads to introducing the topic: the lubrication system. Present the learning objectives clearly.
Content Delivery (30 minutes): Utilize diagrams, charts, or actual lubrication system components (if available, e.g., an oil pump, filter) to visually demonstrate parts. Systematically explain each major component of the lubrication system (Oil pan, pump, filter, etc.) using clear language, linking each part to its function and merchandising relevance. Use a large diagram to trace the flow of oil through the engine, explaining the working principle step-by-step. Explain different types of engine oils, viscosity grades, and API ratings. Provide examples of common grades seen in Nigerian markets (e.g., 20W-50 for older cars, 5W-30 for newer ones) and local brands. Discuss common issues related to the lubrication system (e.g., low oil pressure, oil leaks, clogged filter, incorrect oil usage) and their impact.
Activity Facilitation (20 minutes): Organize students into small groups for the component identification and discussion activity. Circulate among groups, providing guidance, clarifying misconceptions, and ensuring active participation. Facilitate a class discussion on the worked example, inviting students to share their reasoning for oil selection.
Summary and Conclusion (5 minutes): Recap key points: major components, their functions, overall system operation, types of oil, and their importance. Address any remaining questions. Assign independent practice questions. 3.
2. Student Activities: Active Listening and Note-Taking (Throughout): Students will listen attentively to explanations, ask clarifying questions, and take notes on key concepts and definitions. Component Identification (Group Activity - 15 minutes): In groups, students will be provided with diagrams or actual spare parts (if available) of lubrication system components (e.g., oil filter, oil pump, dipstick, oil pressure sensor). They will identify and label each part, and briefly discuss its function within the group. Scenario-Based Discussion (Group Activity - 10 minutes): Students will be presented with the "Worked Example" scenario (selecting engine oil for a Toyota Corolla in Lagos traffic). Each group will discuss and formulate a recommendation, justifying their choice of oil type, viscosity, and API rating, considering cost vs. protection. Q&A Session (Individual/Class - 5 minutes): Students will ask questions about any confusing aspects of the lubrication system or oil types.
Automobile Spare Parts Retailing (Economic Integration): Understanding the lubrication system and its parts is directly applicable to managing and working in spare parts stores prevalent across Nigeria, such as those in Ladipo Market (Lagos), Nkpor (Anambra), or Zaria Road (Kano). Merchandisers need to correctly identify parts requested by mechanics and customers (e.g., "oil filter for a Siena," "oil pump for an Accord"). Knowledge of different oil types and their application for various vehicle makes and models common in Nigeria (e.g., Toyota, Honda, Mercedes, Peugeot) allows for accurate recommendations, boosting sales and customer trust. Vehicle Maintenance and Longevity (Community/Environmental Integration): Proper lubrication is the bedrock of vehicle longevity. In Nigeria, where vehicle ownership is a significant investment and reliance on public transport is high, understanding lubrication helps individuals and fleet managers make informed decisions about engine oil and filter changes. This reduces premature engine failure, saving costs for individuals and businesses, contributing to economic stability. Environmentally, correct oil usage and timely changes reduce harmful emissions and the amount of waste oil generated, promoting sustainable practices if disposed of properly. Preventive Maintenance and Troubleshooting (Community Safety/Economic Integration): Knowledge of lubrication system components allows for early detection of potential problems (e.g., identifying symptoms of low oil pressure, oil leaks, or recognizing clogged filters). This prevents costly engine repairs or replacements that can arise from neglected lubrication. For commercial vehicles (e.g., 'Danfo' buses, 'Okada' motorcycles, haulage trucks), this translates directly into reduced downtime and improved operational efficiency, which is vital for the Nigerian economy and the safety of commuters.