Diesel vs Gas Engine. What’s the Difference? Which Lasts Longer?

Did you know, as per the studies of the U.S. Department of Energy, that diesel engines provide 30-35% more fuel economy than gasoline engines? Given the structure and design of diesel engines, they function with a combustion process that is leaner and burns less fuel than a gasoline engine. Moreover, diesel fuel comes with better energy density than gasoline, which means less fuel is needed to create the same power as gas, enhancing the overall fuel economy.

Did you know? Both diesel engines, as well as gasoline engines, are internal combustion engines. That said, there are numerous minute and significant differences in their operations which is why when it comes to industrial use, diesel engines are often preferred. But you don’t need to take our word for it! Let us spill the beans on various aspects of these engines, and once you read through them, you can make the final call! 

Thermal Efficiency

Thermal efficiency can be loosely defined as the expected production of work by a fuel. Diesel engines are known to be 20% more thermally efficient than their gasoline counterparts, thereby ensuring a 20% better fuel efficiency. Moreover, as thermal efficiency increases, the power and torque also witness a subsequent increase. As you may have guessed, the greater torque application leads to increased capacity for carrying heavy loads. This directly implies that using a diesel engine offers greater value for money.    

Operating Costs

The revolutions per minute in a diesel engine are much lesser than that in gasoline engines, which is precisely why diesel engines are subject to lesser wear and tear. Not only does this help in enhancing the overall longevity of the engine, but also ensures relatively lower operational costs. This aspect when combined with higher fuel efficiency makes diesel engines ideal for use in power generators, and heavy vehicles such as trucks, bulldozers, graders, and even cruise ships!

Combustion Type: Gas and Diesel Engines

Gasoline intrinsically has a high volatility point, but a lower flashpoint. Hence, the combustion of a gas is the result of a spark igniting the fuel compressed with fresh air, which eventually leads to the running of the engines. Diesel engines, on the other hand, do not make use of a spark. Instead, in a diesel engine, the fuel is suddenly exposed to a high temperature, as well as compressed atmospheric air containing oxygen which leads to the ignition of the engine. Simply put, a Gasoline Engine is a Spark-Fired Combustion Engine, while a Diesel Engine is a Compression Combustion Engine. 

The low volatility of diesel engines, which is essentially the reason behind the compression ignition, is what makes diesel engines safer when used in remote locations or under extreme conditions such as that in the case of mining. 

Fuel Costs and Efficiency

As a result of increased air compression, diesel engines operate at a relatively higher temperature which leads to the more efficient conversion of thermal energy to mechanical energy. As is evident, this phenomenon makes diesel engines much more efficient than gas engines, sometimes by as high as 40%. Hence, regardless of the difference between the price of diesel and gasoline, diesel engines always prove to be more cost-effective. 

Torque (Horsepower)

Owing to their high compression ratio, diesel engines enjoy the ability to generate a higher torque at relatively lower engine speeds. Moreover, diesel is more energy-rich than gasoline by at least 12%. Both these factors combined, make diesel engines ideal for applications with heavier loads. 

Maintenance costs

Since diesel engines are devoid of spark plugs, and diesel happens to be a superior lubricant than gasoline, it produces relatively fewer pollutants and corrosive agents. Moreover, diesel generators suffer lesser wear and tear due to their inherently low RPM. All of these factors ensure that the maintenance cost of diesel engines is much lower than that of gasoline-powered engines. 

Gas vs. Diesel Engine: A Quick Glance

Let’s take a quick glance at the differences between gas vs. diesel engines: 

Gas vs. Diesel Engine – Which Lasts Longer?

Life Expectancy is yet another aspect where Diesel Engines ace the scoring board! Gasoline engines are known to show signs of wear and tear and experience reduced fuel efficiency once they hit the 120K to 150K mile mark. Contrastingly, diesel engines work flawlessly until they reach the 200K to 300K mile mark. Even after they reach this threshold, all that needs to be done is the replacement of the removable liner and not the entire engine. Clearly, diesel engines enjoy a much longer life span than gas engines. But, there’s more. Diesel engine compression is 20:1, while that of gas engines is 10:1. This implies that the compression of air is almost double in diesel engines which is why parts therein such as block and cylinder heads, crankshafts, pistons, and valves are designed to be more resilient. Moreover, the higher compression ensures complete combustion of the fuel, thereby ensuring that the exhaust of diesel engines is comparatively less corrosive thus contributing to the long service life for the components of the engine as well as the engine on the whole. 

A Word from Swift Equipment

All of the above-mentioned aspects combined, prove that diesel engines are more than just suitable for industrial equipment as well as heavy-duty vehicles including trains and ships, along with power generators. Needless to say, the higher energy density of diesel fuel diesel as a fuel adds to the list of advantages. 

If you too are on the lookout for a new or used diesel engine for your industrial setup, then get in touch with our experts at Swift Equipment and we will help you pick the most promising make and model that best suits your needs, preferences and most importantly your budget! 

Common Questions About Diesel vs Gas Engines

Q1. What are some of the limitations of diesel engines?

Some of the most prominent drawbacks of diesel engines include –

• Overt noisiness 
• Difficulty in starting the vehicle
• Oil oxidation
• Improper weight viscosity
• Faulty lead/acid storage battery

Q2. What is the difference between diesel and gasoline as fuels?

There are some critical differences between diesel and gasoline as fuels. To begin with, diesel evaporates relatively more gradually than gasoline owing to its heavier and oilier consistency. Diesel is also known to have a higher boiling point than gasoline, which enables it to produce more power and, in turn, be more efficient than gasoline as a fuel. 

Q3. Why does diesel offer better mileage than gas?

Diesel engines are highly fuel efficient and come with low-end torque compared to same-sized gas engines. Moreover, diesel fuel includes almost 10-15% more energy than gas. 

Q4. Is diesel engine maintenance better than gas engines?

Diesel engines are built with a structure that is simple to access, and these engines contain fewer moving parts as compared to gas engines.

Q5. Does diesel fuel fall under the category of fossil fuels?

Conventional diesel falls under the fossil fuel category as it is produced from crude oil.

Q6. Why are diesel engines highly preferred over other engines?

Diesel engines are built to offer better acceleration, more hauling potential and doing than other engines. Moreover, they compress air faster and deliver better power.

Q7. Do diesel engines last longer than gas engines?

Yes, diesel engines are typically more durable than gasoline engines. Diesel engines usually have longer lifespans because they are designed to withstand the increased compression involved in the diesel combustion process.

Q8. What is the lifespan of a diesel engine?

A standard diesel engine may last between 400,000 and 1,000,000 miles, but a gas engine can last approximately 200,000 miles only.