Diesel Generator Buyer's Guide

When to Use Home and Commercial Diesel Generators

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By Jared G.

Generator Expert

Diesel is synonymous with power in our culture. Big rigs, smoke, and burly truck drivers come to mind, but did you know that this same power is used in generators?

A commercial or home diesel generator can provide higher efficiencies and improved dependability in certain applications. Our diesel generator buyer’s guide will explain just what makes this fuel so powerful and how to make it work for you.

What is Diesel?

Diesel is a liquid fuel that ignites in an engine by heat and compression instead of spark and is used in various heavy pieces of equipment, like generators.

Compared to gas, diesel is oilier and has a higher boiling rate. By volume, diesel contains between 10-15% more energy, which translates to greater power and efficiency.

How Does a Diesel Engine Work?

A generator diesel engine operates using the same four-stroke principles as a gas engine but differs in the combustion process:

1. Intake Stroke: Air enters the engine cylinder, pushing the piston down.
2. Compression Stroke: As the piston moves back up, it compresses the air.
3. Power Stroke: When the piston reaches the top of the cylinder, a fuel injector injects diesel into the super-compressed air, causing spontaneous combustion (without using a spark plug) which forces the piston down.
4. Exhaust Stroke: The piston moves back to the top of the cylinder, pushing exhaust gases out.

The reason diesel generator engines don’t require a spark plug to ignite the air/fuel mixture is because the air is compressed much more than in a gas engine. The tighter the air is compressed, the hotter it gets.

The level of compression is measured by the compression ratio. An engine compression ratio is the ratio of the maximum to minimum volume in the cylinder. In other words, how much space is in the cylinder when the piston is at the very bottom versus how much space is there when the piston is at the very top.

Most gas engines have compression ratios of between 8:1 and 12:1. Diesel engines have compression ratios as high as 20:1, which compresses the air into such a small space that it becomes hot enough to combust without a spark plug.

The other big difference between gas and diesel engines is in how the fuel is added. In carbureted gasoline engines, the intake valve releases air/fuel into the cylinder as a mixture. Diesel engines, like fuel-injected gas engines, inject the fuel right before the power stroke when the air has been compressed.

Because the air is packed together so tightly at this point, the fuel molecules can react with more oxygen, resulting in more power. This also results in greater fuel efficiency than in a gas engine.

Is Diesel Better than Gas?

With its higher power output and greater efficiency, a diesel generator is better suited for high-demand or remote applications than gas. 

Diesel generators are larger and more robust than gas generators in order to handle the higher power loads. These engines are almost always liquid-cooled rather than air-cooled.

In terms of price, diesel generators tend to cost more, mainly due to their larger, liquid-cooled engines. Less overall maintenance is required for diesel generators, but, when it is required, tends to be more expensive.

Diesel Generators Gas Generators     More Power Less Power Higher Fuel Efficiency Lower Fuel Efficiency Larger More Compact Mostly Liquid-Cooled Mostly Air-Cooled Less Overall Maintenance More Overall Maintenance More Expensive Less Expensive

 

Diesel Commercial Generators

Commercial applications tend to use diesel generators more often than residential ones. They are common in the mining, construction, marine, and telecommunications industries due to their rugged build and power.

The fuel and maintenance savings are also popular among commercial owners, who often put their generators under the strain of heavy, long-term use. A diesel generator is the undisputed better option for commercial applications.

Home Diesel Generators

Although much less common, home standby diesel generators can benefit homeowners for all the same reasons. 

Homeowners have often stayed away from diesel because they associate it with toxicity and noise. However, newer diesel engines are becoming quieter, and their toxic emissions are comparable to those of gasoline.

Diesel is also less flammable than gasoline and safer to store. During emergency situations like hurricanes or earthquakes, diesel may also be easier to obtain--and that's when you would need your generator the most.

Finally, remote homeowners who aren't connected to a natural gas line might need a diesel generator. There are even smaller units for those who would like a portable diesel generator, such as hunters in a lodge.

Power in Your Hands

Diesel generators give you more available power to get the job done, and you don't even have to be a truck driver.

If you have any questions about picking a diesel generator, please give us a call at 1 (800) 800-3317.

 NEXT: View All Diesel Generators

If you want to learn more, please visit our website how do diesel generators work.

By Jared G.

Generator Expert

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Introduction

Diesel generators have been a cornerstone of backup power generation for decades, providing reliable and consistent electricity during times of grid outages or in remote locations where a stable power source is essential. These machines, powered by diesel engines, have found applications in various sectors including residential, commercial, industrial, and even in critical facilities such as hospitals and data centers. In this comprehensive article, we will delve into the intricacies of diesel generators, exploring their working principle, components, applications, advantages, and environmental considerations.

Working Principle

At its core, a diesel generator is a combination of a diesel engine and an electric generator (alternator). The process of converting diesel fuel into electrical power involves several key steps:

1. Diesel Engine Operation: Diesel engines, renowned for their durability and efficiency, work on the principle of internal combustion. Air is drawn into the engine's combustion chamber, compressed at high pressures, and then fuel (diesel) is injected. The heat generated by the compressed air ignites the fuel, causing it to burn and expand rapidly. This expansion forces the piston down, turning the engine's crankshaft and converting linear motion into rotational motion.
2. Generator Operation: The mechanical energy produced by the diesel engine's crankshaft is transferred to the generator's rotor, which is surrounded by stationary coils of wire. As the rotor spins, it induces a magnetic field in the coils through electromagnetic induction, resulting in the generation of alternating current (AC) electricity.
3. Voltage Regulation: The generated AC voltage typically requires regulation to ensure it stays within acceptable limits. This is achieved using voltage regulators and control systems that adjust the engine's speed and/or the generator's excitation level.

Components of a Diesel Generator

1. Diesel Engine: This is the heart of the generator, responsible for converting diesel fuel into mechanical energy.
2. Alternator (Generator): The alternator consists of a rotor and stator, responsible for converting the mechanical energy from the engine into electrical power.
3. Voltage Regulator: This component maintains a consistent voltage output by adjusting the excitation of the generator.
4. Cooling System: Diesel engines generate a significant amount of heat, and efficient cooling systems (air or liquid-based) are critical to prevent overheating.
5. Fuel System: This includes components like the fuel tank, fuel pump, and injectors responsible for delivering diesel fuel to the engine.
6. Exhaust System: A diesel engine emits exhaust gases during combustion. An exhaust system removes and directs these gases safely away from the generator.
7. Control Panel: The control panel houses various instruments and controls for starting, stopping, and monitoring the generator's performance.
8. Battery and Starter Motor: The battery provides the initial power needed to start the diesel engine, and the starter motor cranks the engine until it's self-sustaining.

Applications

Diesel generators are employed across a wide range of applications due to their reliability and ability to provide power in diverse scenarios:

1. Emergency Backup Power: Critical facilities such as hospitals, data centers, and emergency response centers rely on diesel generators to provide seamless power during grid outages.
2. Remote Locations: Diesel generators are used in remote areas where access to the electrical grid is limited or non-existent, such as construction sites, mining operations, and off-grid communities.
3. Peak Load Management: In locations with high demand for electricity during certain periods, diesel generators can be used to supplement the grid during peak load times.
4. Telecommunications: Mobile cell towers, communication relay stations, and remote communication facilities utilize diesel generators to ensure continuous connectivity.
5. Industrial and Commercial Settings: Manufacturing plants, shopping malls, and other large-scale enterprises rely on diesel generators to prevent production losses and maintain customer service during power interruptions.

Advantages

1. Reliability: Diesel generators are known for their reliability, durability, and long operational life.
2. Fuel Availability: Diesel fuel is widely available globally, making it a convenient choice for backup power.
3. Efficiency: Diesel engines are more fuel-efficient than their gasoline counterparts, resulting in lower operating costs.
4. High Torque: Diesel engines provide high torque at low speeds, making them suitable for heavy loads and sudden power demands.

Environmental Considerations

While diesel generators offer several advantages, they also have environmental considerations:

1. Emissions: Diesel engines emit pollutants such as nitrogen oxides (NOx), particulate matter (PM), and sulfur dioxide (SO2), contributing to air pollution.
2. Noise: Diesel generators can be noisy, which may pose a challenge in residential areas or noise-sensitive environments.
3. Carbon Emissions: Diesel fuel combustion releases carbon dioxide (CO2), a greenhouse gas contributing to climate change.

Conclusion

Diesel generators play a crucial role in providing reliable backup power across a range of applications. Their robustness, efficiency, and fuel availability have made them a staple in scenarios where a stable power source is vital. However, the environmental impact of diesel generators, especially concerning emissions, should be carefully considered when choosing their application. As technology advances, efforts to mitigate their environmental footprint continue through the development of cleaner diesel engines, alternative fuels, and hybrid power solutions.

Contact us to discuss your requirements of genset perkins. Our experienced sales team can help you identify the options that best suit your needs.