What is blowby in engine? Blowby refers to the leakage of combustion gases past the piston rings and cylinder walls in an internal combustion engine. This leakage, often a result of insufficient piston ring seal or cylinder wall imperfections, significantly impacts engine performance, efficiency, and emissions. Understanding the mechanisms, effects, and mitigation strategies for blowby is crucial for optimizing engine design and operation.
Blowby occurs due to various factors, including piston ring wear, cylinder wall imperfections, and insufficient engine lubrication. This leakage leads to a loss of power, increased fuel consumption, and higher emissions, ultimately affecting the engine’s overall performance and lifespan. Different engine types, such as petrol and diesel, exhibit varying sensitivities to blowby, necessitating tailored mitigation strategies.
Definition and Explanation
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A creeping, insidious enemy lurks within the heart of every internal combustion engine: blowby. This insidious leakage of combustion gases past the piston rings and cylinder walls robs the engine of its vitality, diminishing its power and efficiency. Understanding blowby is paramount to maximizing engine performance and longevity.Blowby, in essence, is the leakage of gases from the combustion chamber past the piston rings and cylinder walls.
This leakage represents a catastrophic loss of pressure and power, a silent drain on the engine’s potential. The mechanisms driving blowby are complex, involving a delicate dance between the pressure gradients within the engine and the integrity of the seals.
Mechanisms of Blowby
The primary culprits behind blowby are worn or damaged piston rings and deteriorated cylinder walls. Insufficient lubrication, high operating temperatures, and excessive pressure differentials within the combustion chamber can exacerbate this issue. The resultant leakage compromises the engine’s ability to compress and ignite the fuel-air mixture, leading to a significant drop in efficiency. The escaping gases carry valuable energy, robbing the engine of its intended output.
Types of Blowby
Blowby manifests in various forms, each with unique consequences for engine performance. One type involves the leakage of gases past the piston rings, often manifesting as visible smoke or a noticeable increase in exhaust emissions. Another type involves the leakage of gases past the cylinder walls, potentially leading to oil contamination of the combustion chamber and subsequent engine wear.
Impact on Engine Performance
Blowby’s detrimental effects on engine performance are profound. The loss of compressed gases reduces the engine’s power output, leading to decreased torque and horsepower. Increased friction due to the presence of contaminants further degrades efficiency. This translates to diminished fuel economy and a noticeable drop in acceleration. In extreme cases, blowby can lead to catastrophic engine failure.
Examples of Blowby Manifestations
In high-performance engines, blowby can be evident as a noticeable plume of smoke exiting the exhaust. In older, less meticulously maintained vehicles, blowby might be subtly evident as a consistent oil consumption issue or a persistent smoky exhaust. Modern engines often incorporate sophisticated sensors and diagnostic tools to detect and quantify blowby, enabling proactive maintenance and preventing catastrophic failures.
Causes of Blowby
| Cause | Description | Impact on Performance | Mitigation Techniques |
|---|---|---|---|
| Worn Piston Rings | Piston rings, critical seals within the engine, wear down over time. This reduces their ability to contain the combustion gases effectively. | Reduced compression, decreased power output, increased fuel consumption, potential engine damage. | Regular maintenance, including piston ring replacement, and use of high-quality engine oil. |
| Damaged Cylinder Walls | Scratches, grooves, or other imperfections on the cylinder walls can allow gases to escape. | Similar to worn piston rings, leading to reduced compression and performance issues. | Proper lubrication, engine maintenance, and potentially cylinder honing or replacement. |
| Insufficient Lubrication | Inadequate lubrication of piston rings and cylinder walls can cause friction and wear, thus accelerating the development of blowby. | Accelerated wear on piston rings and cylinder walls, leading to increased blowby and potential engine damage. | Using the correct viscosity engine oil and maintaining proper oil levels. |
| Excessive Combustion Pressure | High combustion pressures can force gases past the seals, leading to increased blowby. | Exacerbates wear on piston rings and cylinder walls, leading to significant performance loss and potentially catastrophic failure. | Tuning the engine’s fuel delivery system, ensuring proper compression ratios, and using the right fuel for the engine. |
Effects of Blowby
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Blowby, the insidious leakage of combustion gases past the piston rings, wreaks havoc on engine performance and longevity. This silent thief, often overlooked, gradually degrades the engine’s health, manifesting in reduced efficiency, increased emissions, and accelerated wear. Understanding its insidious effects is crucial for maintaining optimal engine operation and preventing costly repairs.
Negative Impact on Engine Efficiency
Blowby represents a significant loss of power. Gases escaping past the piston rings carry with them valuable energy, energy that could otherwise contribute to the engine’s output. This leakage reduces the effective compression ratio, diminishing the engine’s ability to extract maximum power from the fuel. Consequently, fuel economy suffers drastically, demanding more fuel input for the same work output.
Consider a scenario where a vehicle experiences a 10% blowby rate; this translates to a significant loss in fuel economy and performance.
Increased Emissions
The unburnt or partially burnt gases escaping via blowby contribute significantly to harmful emissions. These pollutants, including hydrocarbons, carbon monoxide, and nitrogen oxides, contaminate the atmosphere and have detrimental environmental consequences. The increased presence of these gases in the exhaust stream negatively impacts air quality and public health. Furthermore, regulatory standards regarding emissions are stringent, and uncontrolled blowby often results in significant violations, leading to potential penalties and legal ramifications.
Impact on Engine Oil Consumption
Blowby contaminates the engine oil, a critical lubricant. The presence of combustion gases within the crankcase elevates the oil’s temperature and degrades its lubricating properties. This results in increased oil consumption as the oil breaks down faster and requires replenishment more frequently. This process can lead to premature engine wear and tear, especially if the oil is not changed regularly.
A severe blowby case can lead to a substantial rise in oil consumption, necessitating frequent oil changes, a considerable cost for maintenance.
Comparison Across Engine Types
The effects of blowby vary across engine types. Petrol engines, with their typically lower compression ratios, often exhibit lower levels of blowby compared to diesel engines, which operate at higher compression pressures. However, even small amounts of blowby in petrol engines can still lead to noticeable performance and efficiency degradation. Diesel engines, due to the higher pressures and temperatures, are more susceptible to increased blowby, leading to potentially greater emission levels and oil consumption.
Long-Term Effects on Engine Components
Uncontrolled blowby accelerates the deterioration of crucial engine components. The abrasive nature of the combustion gases and the resulting heat buildup can cause significant wear and tear on piston rings, cylinder walls, and other internal parts. This accelerated wear shortens the engine’s lifespan, leading to costly repairs and potential engine failure. This is especially true in older engines, where the components may not be as resilient to the damaging effects of blowby.
Effects of Blowby on Engine Parameters
| Engine Parameter | Effect of Blowby |
|---|---|
| Power Output | Significant reduction, as energy is lost through leakage. |
| Fuel Economy | Dramatic decrease, requiring more fuel to achieve the same output. |
| Emissions | Increased levels of harmful pollutants, leading to environmental concerns. |
| Oil Consumption | Increased rate of oil consumption, necessitating frequent oil changes. |
| Engine Life | Accelerated wear and tear, potentially leading to premature failure. |
Measurement and Diagnosis
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Unveiling the insidious nature of blowby requires meticulous measurement and diagnosis. A silent saboteur within the engine’s heart, blowby can cripple performance and prematurely age critical components. Accurate detection and subsequent corrective action are paramount for maintaining engine health and longevity.
Common Blowby Measurement Methods
Precise quantification of blowby is crucial for effective diagnosis. Several methods, each with varying degrees of complexity and cost, provide valuable insights into the extent of leakage. These methods range from rudimentary visual inspections to sophisticated instrumentation.
- Oil Consumption Analysis: A straightforward, yet informative, method involves meticulously monitoring the rate of oil consumption over time. Consistent increases often signal the presence of significant blowby, allowing for a preliminary assessment of the extent of the problem. This method is relatively inexpensive but lacks the precision of more advanced techniques.
- Compression Ratio Testing: This method measures the pressure within the engine cylinders during the compression stroke. A noticeable drop in compression ratio compared to expected values suggests significant blowby, indicating leakage past the piston rings or other sealing components. This method provides a direct measure of sealing integrity.
- Blowby Gas Analysis: Advanced methods involve capturing and analyzing the blowby gases. This analysis provides insights into the composition of the gases, aiding in pinpointing the source of the leakage. Sophisticated gas chromatographs allow for identification of specific compounds, offering a detailed understanding of the leakage characteristics. This approach is often employed in advanced diagnostics and offers high accuracy.
Procedures for Diagnosing Blowby
Diagnosing blowby requires a systematic approach. The process begins with a thorough visual inspection to identify potential visual clues and progresses to more involved testing.
- Visual Inspection: Carefully examine the engine components for any signs of excessive oil accumulation or unusual discoloration. Look for oil staining on the cylinder walls, piston rings, and valve seats. A visual inspection, though preliminary, can highlight areas requiring further investigation. A build-up of soot on the cylinder walls, for example, is a sign of incomplete combustion, which is often related to blowby.
- Instrumentation Use: Utilize appropriate instruments, such as compression testers or blowby measurement devices, to perform accurate measurements. Record readings precisely and compare them to the manufacturer’s specifications.
- Data Analysis: Analyze the collected data and compare it with established norms. Significant deviations from normal operating parameters should prompt further investigation. The data obtained should provide a clear picture of the extent of the blowby and pinpoint the root cause.
Blowby Measurement Techniques Comparison
A comparative analysis of different blowby measurement techniques offers insights into their respective strengths and weaknesses.
| Technique | Accuracy | Cost | Complexity |
|---|---|---|---|
| Oil Consumption Analysis | Low | Low | Simple |
| Compression Ratio Testing | Medium | Medium | Moderate |
| Blowby Gas Analysis | High | High | High |
Visual Inspection Steps
A systematic visual inspection is crucial for pinpointing potential blowby-related issues.
- Inspect Piston Rings: Carefully examine the piston rings for wear, damage, or excessive oil accumulation. Damaged piston rings are a common culprit in blowby.
- Examine Cylinder Walls: Inspect the cylinder walls for any signs of oil staining or excessive wear. This could indicate that piston rings are failing.
- Check Valve Seats: Assess the valve seats for wear, damage, or leakage. Faulty valve seats can contribute to blowby. Excessive wear or leakage will be evident in the form of oil stains or discoloration around the valve area.
Diagnostic Flowchart
A flowchart provides a streamlined approach to blowby diagnosis, guiding technicians through the process systematically.
[Insert a flowchart image here illustrating the diagnostic process. The flowchart should clearly depict the steps, including visual inspection, instrumentation use, data analysis, and potential further investigations.]
Mitigation Strategies
The insidious presence of blowby, that silent thief of engine performance and efficiency, demands decisive countermeasures. This insidious leakage, the clandestine escape of combustion products past piston rings, must be contained, its destructive effects thwarted. The strategies detailed herein represent a multifaceted approach to combating this pervasive issue, ensuring optimal engine health and longevity.
Piston Ring Design
Piston rings, the unsung heroes of combustion, are critical in preventing blowby. Their precise design dictates the sealing effectiveness, and their quality dictates the engine’s longevity. Sophisticated ring designs, often incorporating advanced materials and geometries, are crucial for achieving minimal leakage. Modern designs frequently feature innovative features such as improved sealing lip profiles and optimized ring groove configurations.
These sophisticated approaches effectively minimize the passage of gases between the piston and cylinder walls.
Engine Modifications
Engine modifications, though often complex and costly, can dramatically reduce blowby. These interventions may include specialized cylinder liners, enhanced piston materials, and modifications to the combustion chamber design to facilitate more efficient sealing. For example, increasing the compression ratio, though increasing risk of detonation, can potentially reduce blowby by increasing the pressure differential across the piston rings. Another example is modifying the piston’s crown shape for improved sealing.
Engine Maintenance
Proper maintenance is not merely a best practice; it is a cornerstone of blowby prevention. Regular inspections, meticulous oil changes, and timely component replacements are vital in preventing the wear and tear that can lead to increased blowby. Ignoring routine maintenance will eventually lead to a gradual deterioration of the engine’s sealing mechanisms, inevitably increasing blowby and reducing performance.
This includes checking for signs of excessive wear on piston rings and other components.
Optimizing Engine Oil
Engine oil, the lifeblood of the engine, plays a significant role in blowby mitigation. A high-quality, viscosity-graded oil formulated for the specific engine application can significantly reduce friction and wear, which, in turn, reduces the risk of blowby. The oil’s ability to coat moving parts minimizes friction, reducing the possibility of component degradation and enhancing sealing. Using an oil with appropriate additives to improve its lubricating properties and seal characteristics can also significantly reduce blowby.
Mitigation Techniques Summary, What is blowby in engine
| Technique | Description | Effectiveness | Cost |
|---|---|---|---|
| Advanced Piston Ring Design | Optimized ring profiles and materials for enhanced sealing | High | Medium-High |
| Engine Modifications (e.g., Cylinder Liners) | Specialized cylinder liners or other component upgrades | Very High | High |
| Rigorous Engine Maintenance | Regular inspections, oil changes, and timely component replacements | Moderate to High | Low to Medium |
| High-Quality Engine Oil | Utilizing viscosity-graded oil with appropriate additives | Moderate | Low to Medium |
Blowby and Emissions
The insidious presence of blowby, the leakage of combustion gases past piston rings and seals, is not merely a mechanical nuisance. It represents a potent threat to the environment, a silent saboteur of clean air. The consequences of uncontrolled blowby extend far beyond the engine’s internal workings, reaching into the atmosphere with detrimental effects. This section delves into the treacherous relationship between blowby and harmful emissions, highlighting the environmental devastation wrought by unchecked leakage.Blowby, a seemingly minor issue, dramatically impacts the exhaust gas composition, introducing uncombusted hydrocarbons and other pollutants.
This contamination, though often imperceptible, contributes significantly to air pollution, jeopardizing both human health and the delicate balance of the ecosystem. The resultant emissions, a toxic cocktail of harmful substances, are a direct consequence of this uncontrolled leakage.
Correlation between Blowby and Harmful Emissions
Blowby introduces unburnt hydrocarbons (HC), nitrogen oxides (NOx), and carbon monoxide (CO) into the exhaust stream. These compounds, though present in trace amounts in controlled combustion processes, become elevated when blowby is uncontrolled. The leakage allows unburnt fuel and lubricating oil to mix with the exhaust gases, creating a potent cocktail of pollutants.
Impact of Blowby on Exhaust Gas Composition
The intrusion of blowby drastically alters the exhaust gas composition. Uncombusted hydrocarbons, along with lubricating oil vapors, increase the overall pollutant concentration. This contamination diminishes the efficiency of exhaust aftertreatment systems, exacerbating the emission problem. The presence of blowby often leads to a substantial increase in unburnt hydrocarbons, resulting in a higher carbon content in the exhaust.
Examples of Emissions Produced Due to Blowby
Numerous harmful emissions are directly linked to blowby. Unburnt hydrocarbons, often represented by their pungent smell, are a major contributor to smog formation. Nitrogen oxides, notorious for their contribution to acid rain and respiratory problems, are also exacerbated by blowby. Carbon monoxide, a colorless, odorless, and poisonous gas, is another significant emission stemming from the incomplete combustion process enabled by blowby.
Environmental Consequences of Uncontrolled Blowby
Uncontrolled blowby contributes significantly to air pollution, leading to smog formation, acid rain, and greenhouse gas emissions. The detrimental effects extend to human health, increasing respiratory illnesses and other health problems. The damage to ecosystems, from the acidification of water bodies to the disruption of ecological balances, is substantial and long-lasting. Uncontrolled blowby compromises the environment’s ability to self-regulate, perpetuating a cycle of pollution.
Methods to Reduce Emissions from Blowby
Several strategies can mitigate the emissions stemming from blowby. Advanced piston ring designs, optimized engine lubrication systems, and improved sealing technologies are crucial. Engine management systems that adjust combustion parameters can also help reduce the likelihood of blowby.
Comparison of Emission Control Strategies for Blowby
| Strategy | Mechanism | Effectiveness | Cost |
|---|---|---|---|
| Improved Piston Ring Design | Enhanced sealing, reduced leakage | High | Moderate |
| Optimized Lubrication System | Reduced friction, lower blowby | Moderate | Low |
| Engine Management System Adjustments | Optimized combustion parameters | Moderate | Low |
| Advanced Sealing Technologies | Minimized leakage through improved seals | High | High |
Blowby and Engine Oil
The insidious encroachment of blowby into the engine’s meticulously crafted lubrication system is a silent, corrosive process. This insidious leakage, a byproduct of the combustion process’s imperfections, slowly but relentlessly degrades the engine’s health, consuming precious oil and compromising its vital function. Understanding the mechanisms and consequences of this encroachment is paramount to maintaining optimal engine performance and longevity.
Oil Consumption Mechanisms
Blowby, the leakage of gases from the combustion chamber into the crankcase, directly contributes to engine oil consumption. This intrusion, a constant leakage through piston rings and cylinder walls, introduces harmful contaminants into the lubricating oil. This leakage introduces significant volumes of uncombusted hydrocarbons, along with combustion byproducts, directly into the crankcase. This introduces a substantial load on the engine’s oil system.
The rate of this intrusion, often correlated with engine load and operating temperature, is a significant factor in oil consumption.
Contamination Mechanisms
The intrusion of blowby into the engine oil is a multifaceted process, influenced by several factors. Unburnt hydrocarbons, carbon monoxide, and other byproducts of incomplete combustion are drawn into the crankcase. These contaminants, mixed with the lubricating oil, gradually alter its composition. The corrosive nature of some blowby components, such as oxides of nitrogen and sulfur, further exacerbates the issue, gradually degrading the oil’s lubricating properties.
This corrosive effect, while subtle at first, accelerates with time and use.
Chemical Changes in Oil
The introduction of blowby alters the oil’s chemical composition, a gradual degradation that progressively diminishes its performance. Unburnt hydrocarbons, for example, polymerize and form varnish-like deposits, clogging oil passages and hindering the flow of lubricant. Furthermore, acids produced by the oxidation of these contaminants cause a significant deterioration in the oil’s base oil molecules, compromising its viscosity and protective properties.
This, in turn, results in increased wear and tear within the engine. The progressive accumulation of these contaminants significantly degrades the oil’s lubricating and protective capabilities.
Monitoring Engine Oil Condition
Regular monitoring of engine oil condition is crucial for detecting the subtle but significant effects of blowby. The appearance of sludge-like deposits or unusual colors in the oil can indicate the presence of blowby contamination. Analyzing the oil’s viscosity, acidity, and the presence of metallic particles can provide critical insights into the engine’s condition. Furthermore, measuring oil consumption rates and correlating them with engine load and operational parameters can provide a valuable indication of blowby’s severity.
These parameters are essential indicators for assessing the degree of blowby and its effects on the engine.
Impact on Lubrication Properties
The presence of blowby contaminants in the engine oil significantly degrades its lubrication properties. The introduction of unburnt hydrocarbons and combustion products reduces the oil’s ability to maintain a protective film on moving engine components, leading to increased friction and wear. The altered viscosity and acidity further compromise the oil’s ability to lubricate effectively, leading to a breakdown in the engine’s protective mechanisms.
The diminished lubricating properties result in a significant acceleration of wear within the engine.
Oil Consumption and Mitigation Strategies
| Oil Consumption Issue | Mitigation Techniques |
|---|---|
| Increased oil consumption due to blowby | Addressing piston ring issues (replacement, honing), sealing improvements, and optimized combustion |
| Presence of contaminants (sludge, varnish) | Regular oil changes, using appropriate oil grades, and employing oil treatment additives |
| Viscosity and acidity changes | Implementing engine maintenance schedules, using high-quality oil, and incorporating oil analysis |
| Progressive wear and tear | Implementing proper maintenance schedules, regular inspection, and addressing any detected issues promptly |
The table above summarizes the connection between blowby and oil consumption and offers practical mitigation strategies. Consistent and diligent maintenance is crucial in mitigating the harmful effects of blowby on engine oil.
Advanced Blowby Control Techniques
The insidious dance of blowby, the leakage of combustion gases past piston rings, relentlessly degrades engine performance and efficiency. Modern advancements, however, offer a formidable arsenal against this insidious enemy, promising a future of leaner, more powerful, and environmentally conscious engines. This section delves into the cutting-edge strategies for controlling blowby, revealing the innovative approaches that are redefining the limits of internal combustion.
Modern Piston Ring Technology
Piston rings, the stalwart guardians against blowby, have undergone significant evolution. Advanced materials, such as high-strength alloys and coatings, enhance their durability and sealing capabilities. Employing sophisticated manufacturing processes, including laser-precision machining and advanced heat treatments, engineers are crafting rings with unprecedented tolerances and sealing profiles. This results in reduced friction and significantly lower blowby rates. Innovative designs, such as segmented rings with variable profiles, dynamically adapt to changing combustion pressures, optimizing sealing performance across a broader operating range.
These advancements represent a quantum leap forward in the battle against blowby, promising engines that are simultaneously more powerful and more efficient.
Advanced Blowby Detection and Monitoring
Proactive monitoring is crucial in managing blowby effectively. Sophisticated sensors, coupled with advanced data analysis algorithms, provide real-time insights into the engine’s operational parameters. These systems, often integrated into engine management systems, can detect subtle changes in pressure differentials, temperature fluctuations, and oil consumption patterns, providing early warnings of impending blowby issues. This allows for proactive intervention, preventing significant damage and optimizing maintenance schedules.
For example, real-time monitoring systems can pinpoint the exact location and extent of blowby, allowing for targeted interventions and localized repairs, thereby preventing widespread damage.
Innovative Approaches for Specific Engine Types
Specific engine designs necessitate tailored solutions. In high-performance engines, advanced ring designs and optimized combustion chambers are employed to mitigate blowby. Hybrid electric vehicles (HEVs) benefit from specialized blowby control strategies, as their unique operating profiles demand different sealing approaches. In diesel engines, advanced lubrication strategies and optimized piston geometries can minimize blowby, contributing to reduced emissions.
Engine Design for Blowby Minimization
Engine design itself plays a crucial role in controlling blowby. Optimizing piston geometries, incorporating advanced combustion chamber designs, and carefully selecting materials contribute to a reduction in leakage paths. Consideration of lubrication strategies, including optimized oil viscosity and flow, is also essential in maintaining a strong sealing barrier. Innovative engine architectures, such as those with optimized scavenging systems, actively draw out combustion gases, further reducing the potential for blowby.
Benefits of Advanced Blowby Control Techniques
Advanced blowby control techniques yield a multitude of benefits. Engines exhibit increased efficiency, leading to improved fuel economy and reduced emissions. Reduced oil consumption translates to lower maintenance costs and a longer engine lifespan. The overall performance and reliability of the engine are significantly enhanced. This translates to a dramatic reduction in repair costs and downtime, leading to greater profitability for manufacturers.
Summary Table of Advanced Blowby Control Techniques
| Technique | Advantages | Disadvantages |
|---|---|---|
| Advanced Piston Ring Technology | Improved sealing, reduced friction, enhanced durability | Potentially higher initial cost, manufacturing complexity |
| Real-Time Blowby Monitoring | Early detection of issues, optimized maintenance, targeted repairs | Requires sophisticated sensors and data analysis systems, potentially high initial investment |
| Engine Design Optimization | Reduced blowby through optimized geometries, combustion chambers, and material selection | Complex design considerations, potential for design trade-offs |
| Engine Specific Approaches (e.g., HEVs, Diesels) | Tailored solutions for specific engine characteristics, improved performance | Design complexity, potential for specialized tooling requirements |
Closure: What Is Blowby In Engine
In conclusion, blowby in engines is a complex issue with significant implications for performance, emissions, and overall engine health. Proper diagnosis and effective mitigation strategies are essential for maintaining optimal engine operation. Advanced technologies and meticulous maintenance practices are critical to minimize blowby and maximize engine lifespan and efficiency.
User Queries
What are the common causes of blowby?
Common causes of blowby include worn or damaged piston rings, improperly fitted piston rings, excessive cylinder wall wear, and insufficient lubrication. Engine design factors, such as piston ring geometry and cylinder wall surface finish, also play a role.
How is blowby measured?
Blowby can be measured using various methods, including oil consumption analysis, gas analysis of exhaust, and direct pressure measurements. Specialized diagnostic equipment and procedures are often used.
What are the long-term effects of uncontrolled blowby?
Uncontrolled blowby can lead to accelerated wear of engine components, reduced engine power and efficiency, increased fuel consumption, and elevated harmful emissions. Severe cases can necessitate costly repairs or even engine replacement.
How does blowby affect engine oil?
Blowby contaminates engine oil with combustion products, degrading its properties and shortening its lifespan. This contamination reduces the oil’s lubricating capacity and increases the rate of oil consumption.
