Future of Engine Building: Converting the Masses - Engine Builder Magazine

Future of Engine Building: Converting the Masses

Rebuilding Diesel Engines to Run on Natural Gas

Engine builders often get requests to convert a stock engine into a performance powerplant. Or to take a modest diesel tractor engine rated at 2,200 horsepower and transform it into a smoke-bellowing pulling machine at 6,000 horsepower.

However, in our third installment on the future of engine building, we’ll take a look at a growth opportunity of another kind – converting a diesel engine into one that runs on natural gas.

This truck is one of several equipped with natural gas engines/fuel systems from Westport Innovations Corp. and could set the tone for many more.
This truck is one of several equipped with natural gas engines/fuel systems from Westport Innovations Corp. and could set the tone for many more.

 

Making the Fuel Switch
Natural gas is a very promising fuel for a wide range of commercial vehicles. For one, natural gas offers comparable horsepower, acceleration and cruise speeds to gasoline or diesel fuel. These days, its cost is much lower than diesel fuel and it is an abundant supply with prices likely to remain the same or even fall over the coming years.

According to some reports, using natural gas over diesel can save a truck operator as much as a $1.50 per gallon at today’s prices.

Also, according to engine designers, natural gas burns much cleaner – with 33% less NOx and 20% lower greenhouse gas emissions than equivalent diesel-fueled engines. And, since natural gas has lower particulate emissions, converted vehicles often need less frequent maintenance because the fuel burns cleaner.

[inpost_gallery post_id=4106 sc_id=”sc1389881880121″ sc_id=”sc1389882059323″]

Omnitek Engineering, Corp., a Vista, CA, company that develops and sells diesel-to-natural gas engine conversion systems, reports that any diesel engine can be converted to natural gas. The company explained that the power level of the engine after conversion depends on numerous issues, such as natural gas quality, power level of the original diesel engine, emission levels required, etc.

Diesel engines converted to natural gas generally require added components as well as some mechanical changes to the engine. Basically, the diesel engine undergoes a complete overhaul and, in the process, transformed from a diesel engine to a natural gas engine (CNG or LNG).

Omnitek also says that thousands of diesel engines are rebuilt to operate on natural gas each year with minimal costs. The company estimates the population of diesel engines around the world, which can be converted using its diesel-to-natural gas conversion system, is in excess of ten million engines.

For companies like Omnitek that embrace this trend, diesel-to-natural gas engine conversions make economic sense for many fleet operators since it’s a viable way to increase the natural gas vehicle population in the most reasonable amount of time.

Engineering Challenges
Diesel engine manufacturers that were interested developing natural gas options have faced some difficult engineering challenges in converting existing diesel products to run on natural gas. One of the biggest changes is that much greater volumes than equivalent liquid diesel fuel – must be carefully regulated and quickly delivered to the cylinder at just the right time in the combustion cycle. Another important consideration is that natural gas requires a temperature of 800°C (1472° F) to ignite compared to 500°C (932° F) for diesel fuel.

The usual approach is to convert the engine to spark ignition, reduce the compression ratio, and feed the gas into the intake manifold where it is mixed with incoming air. This method usually results in lower efficiency and reduced power and torque, however, and it is not well suited to heavy-duty trucks where fuel efficiency and engine performance are critical.

According to Westport Innovations Corp. in Vancouver, Canada, its engineers developed a fuel injector specifically designed for natural gas engines that is designed to solve this problem. The Westport HPDI (high-pressure direct injection) system utilizes an injector tip assembly with dual-concentric needle valves. The needle valves are opened and closed by a hydraulic circuit actuated by a set of electromagnetic solenoids.

The opening of the valve injects a small amount of diesel fuel that serves as an ignition source. This small amount of fuel acts as a liquid spark plug. It is followed in a matter of milliseconds by large quantities of natural gas sprayed at high pressure into the combustion chamber.

You May Also Like

NMRA/NMCA Announce Augustine Herrera as National Tech Director

ProMedia Events and Publishing, the parent company of the Holley NMRA Ford Nationals and NMCA Muscle Car Nationals, has announced Augustine Herrera as the new NMRA/NMCA National Tech Director. His duties include overseeing fair competition in both drag racing series and leading the on-site tech staff at all national events.  “Augustine joined our team in

ProMedia Events and Publishing, the parent company of the Holley NMRA Ford Nationals and NMCA Muscle Car Nationals, has announced Augustine Herrera as the new NMRA/NMCA National Tech Director. His duties include overseeing fair competition in both drag racing series and leading the on-site tech staff at all national events. 

Shop Solutions November 2021

Check out these Shop Solutions from builders across the country!

Cam Center
Holley Classic Truck Battery Tray and Hold Down

Holley Classic Trucks can battery trays for 1981-1987 C/K Series trucks and Blazer/Jimmy/Suburban manufactured to precisely mimic the factory look with all of the original holes and contours. Related Articles – Rocker Arm Tech – Part 1 – Automotive Specialty-Equipment Retail Sales Reach New High – Rebuilders Choice Made from heavy-gauge steel and EDP coated

Holley Battery Tray
Rocker Arm Tech – Part 1

In this episode of Steve Tech, Steve Morris breaks down the fundamentals of rocker arms, rocker arm stands and valvetrain rocker arm geometry. Class is in session! Related Articles – The SCAT Story – Numbers Don’t Tell The Whole Story – Performance Rocker Arms

Automotive Specialty-Equipment Retail Sales Reach New High

Despite what occurred throughout 2020, the specialty-equipment industry showed resilience with industry retail sales climbing from $46.2 billion to a new high of $47.89 billion in the U.S., according to the new 2021 SEMA Market Report. Related Articles – Future of Engine Building: The Road Ahead for Machining – AAIA Offering Free Webinar on Health

Other Posts

The Story of Callies Performance Products

We recently got access to go inside Callies Performance Products‘ Fostoria, OH facility and speak with owner Rick Norton and his son Heath Norton, up close and personal. What we got was the story of how Callies came to be a leading manufacturer of engine components, and where the company is going next. Related Articles

Dream Engine Giveaway Ep. 4 – Bottom End Assembly

Now that Chris has checked all our specs, we begin to assemble the bottom end components of our small block Ford such as the rotating assembly, main and rod bearings and the camshaft. Next episode, we will be getting into our cylinder head assembly and more of the valvetrain components. Related Articles – Twin-Turbo LB7

One-on-One with Jillian McLaughlin of Precision Machine Engine

Earlier this year we caught up with Jillian McLaughlin of Precision Machine Engine (PME) out in North Highlands, CA. Jillian is just a few years into her engine shop journey, but she’s picked up the ins and outs of numerous engine work quickly, and can be seen on Instagram doing her thing for PME. We

King to Host PRI Tech Seminar and Launches Can-Am Bearings

King Engine Bearings will be hosting an engine builder roundtable at the 2022 Performance Racing Industry (PRI) trade show in Indianapolis.  “Master the Engine” seminar will be hosted by King’s Technical Manager, Ron Sledge, with six engine builders in a Q&A format, uncovering the latest engine building trends, best practices, and insider tips and tricks.