Maintaining and servicing commercial natural gas engines

two semi trucks parked

Natural gas engines have been around for decades now. They offer a range of benefits, including reduced emissions and operating costs compared to diesel engines. Despite a high degree of parts commonality, there are some maintenance differences between natural gas engines and diesel engines. This article delves into the world of natural gas engine maintenance and service. It provides insights into the unique requirements and best practices for keeping these engines running smoothly. 

Natural gas engines have a maintenance-free exhaust treatment system

A major benefit of natural gas engines is that they do not require a complicated exhaust treatment system. In diesel vehicles, these systems are used to treat post-combustion gases by filtering out soot and reducing NOx emissions. Over time, the filters clog and must be cleaned or replaced to ensure performance. 

Natural gas engines are, in contrast, intrinsically clean. They produce very little NOx and virtually no soot, so only light exhaust aftertreatment is needed. Cummins’ engines use a maintenance-free three-way catalyst exhaust treatment system, eliminating the need for filter changes or replacement of exhaust control systems. This reduces the cost and complexity of maintenance and decreases fleet downtime. 

Natural gas engine best maintenance practices

When maintaining a natural gas engine, there are several best practices that need to be kept in mind. First, it’s important to factor in idle time to the maintenance schedule. That’s why it is recommended to track hours on the engine and not just miles driven when tracking maintenance intervals. This is especially important to keep in mind with vocational and transit applications given the high level of idle time inherent to those duty cycles. 

Using genuine Cummins parts such as spark plugs and oil, can significantly reduce unexpected issues and downtime of natural gas vehicles. All Cummins components have undergone validation to ensure they meet the company's design standards and emission certifications. 

Low pressure fuel filters should be drained regularly as a routine maintenance practice. This is a quick process that involves loosening the filter and allowing the fuel to drain out. This helps to protect the engine and allows for the identification of any issues in the compressor. 

Checking for the latest ECM calibration at every spark plug change is also recommended. These calibrations are typically released once or twice a year. If a fleet has already invested in software tools for updating diesel engines, the same tools can be used for natural gas engines.

It’s critical to follow recommended maintenance intervals for natural gas engines

Natural gas engines aren’t as forgiving as diesel engines when it comes to missing service intervals, especially oil drains. Cummins has put significant effort into educating fleets over the years about the best way to track the time on the engine to make sure the right intervals are being met, whether engine hours or miles driven is the primary metric being used. 

The CES 20092 spec oil is the recommended oil for spark ignition engines and is the result of a joint effort by Cummins and Valvoline. This oil can be used on diesel, natural gas and gasoline engines.

It is also important to replace the spark plugs per the recommended service schedule. During installation, care should be taken to maintain the cleanliness of the spark plugs and to install them using the correct torque. Only manufacturer-approved spark plugs should be used as they are extensively tested and certified for each engine. Aftermarket spark plugs haven’t been proven to meet the emissions certifications. You also should not adjust the gap on your new spark plugs or check the gap with a friction gauge. If a new spark plug appears to be out of spec, return it for a replacement.

The following table shows the recommended maintenance intervals for several additional components. These include crankcase breather, ignition coil extension, standard coolant and coolant filter. 

chart of general engine maintenance requirements

Failure to follow these maintenance intervals may lead to engine problems. These potentially include misfire, damage to the catalyst and ignition coil extension, front or rear main seal leaks and even piston failures. In case of any such issues, fleet owners should reconsider their maintenance schedule and ensure maintenance is being performed on time.

Cummins is set to launch the highly anticipated X15N engine in 2024. With this natural gas engine, Cummins is working on synchronizing maintenance intervals to allow users to complete more service events at once. Below you’ll find the X15N maintenance intervals.

X15N Maintenance intervals chart

 

Natural gas vehicle facilities and mechanics

Facilities that service natural gas vehicles require specific safety measures to prevent potential safety hazards. Ventilation, path control, space heating, electrical wiring, equipment installation, and methane detection and control systems are some of the safety measures that need to be taken. For additional safety questions, fleets can connect with their local Clean Cities coordinator. 

Experienced mechanics require only supplemental training to work on natural gas vehicles, since their maintenance closely resembles the maintenance of traditional vehicles. There are examples of fleets that run a combination of diesel and natural gas engines. Fleets with large numbers of natural gas vehicles often keep natural gas and diesel maintenance separate for efficiency. However, maintenance for both natural gas and diesel vehicle is possible at the same premises if there is at least one dedicated bay with the appropriate safety considerations for natural gas systems. The joint venture between Cummins and Rush Enterprises will provide customers with a service network through Rush Truck Centers’ dealerships and Cummins’ distributors. With over 250 locations in the US and Canada, both companies' networks will be equipped with certified technicians and a comprehensive natural gas vehicle parts inventory.

Unlike diesel, natural gas cannot be spilled. Any leaking natural gas, being in gaseous form, will quickly dissipate, and will not soak gloves or overalls, or leave residues on surfaces. Maintenance crews may have a more pleasant experience working on a cleaner, soot-free engine. 

Puneet Singh Jhawar

Puneet Singh Jhawar

Puneet Singh Jhawar is the General Manager of the global natural gas business for Cummins Inc. In this role, he is responsible for the product vision, financial management and overall performance of the natural gas business. Over his 14-year career at Cummins, Jhawar has cultivated successful relationships with a number of Cummins’ largest customers. Jhawar has extensive global experience, with roles based in the Middle East, India, Europe and the US.

Unpacking CARB’s trucking rules, regulations and legal challenges

Semi truck driving

The state of California has positioned itself as a central figure in a revolutionary shift from a 100-year path of internal combustion engines (ICE) used in commercial transportation. Within a three-year span, the state has adopted the world’s most stringent commercial vehicle regulations: Advanced Clean Trucks (ACT), the Heavy-Duty Engine and Vehicle Omnibus Regulation and Advanced Clean Fleets (ACF). The three rules work together to gradually transition commercial trucks, buses and vans to zero emission vehicles (ZEVs).

The stringent regulations have generated plenty of praise, collaboration, concern and even legal challenges. Turning away from familiar and trusted technology will be anything but easy but the industry is proving it is possible.

Questions around ZEV cost and capability relative to ICE are not taken lightly by Cummins nor other players in one of the nation’s most critical industries.

As with prior emissions legislation, amendments will undoubtedly emerge as collaborative efforts between policymakers and industry continue. That is currently the case with the Omnibus regulation as proposed amendments are under review by the Environmental Protection Agency. Some of the amendments in question focus on diesel engine testing, warranty periods and aftertreatment. 

“Omnibus, the amended version, got resubmitted to EPA and is calling for increased legacy allowances,” explained Tom Swenson, Director of Global Regulatory Affairs.

Emission legislation passed by the California Air Resources Board (CARB) requires a Clean Air Act waiver from the EPA when it proves stricter than federal policy. CARB has been receiving federal waivers for its emissions policies since the 1960s given its ongoing battles with air pollution.

Geographical features such as valleys and mountains appearing throughout the state can hinder air circulation to keep pollutants hanging around.

“The San Joaquin Valley in California, for example, is like a little trap of NOx,” Uma Vajapeyazula, North American Market Strategy Director, described.

Eager to overcome its unique air pollution issues, CARB has kept a close eye on ZEV development. Once board members decided the technology was up to the challenge of replacing ICE trucks up to Class 8, CARB adopted the Advanced Clean Trucks (ACT) rule in June of 2020. To date, it’s the only one of the three ZEV polices that has received an EPA waiver.

 The ACT rule requires that manufacturers who certify chassis or complete vehicles with a gross vehicle weight rating (GVWR) greater than 8,500 lbs. sell zero-emission vehicles (ZEV) at an increasing percentage of their annual California sales starting with the 2024 model year. The annual reporting began with the 2021 model year.

 OEMs struggling to sell ZEVs can buy ZEV credits from other manufacturers to unlock sales of their ICE vehicles. However, there’s concern that funds used to purchase ZEV credits could impact their bottom line.

 “One question is, ‘Will ZEV credit trades happen between competitors?’” Swenson said.

In September 2021, CARB adopted the Heavy-Duty Engine and Vehicle Omnibus Regulation to “drastically cut smog-forming nitrogen oxides (NOx) from conventional heavy-duty engines. The Omnibus Regulation will significantly increase the stringency of NOx emissions standards and will also lengthen the useful life and emissions warranty of heavy-duty diesel engines for use in vehicles with a gross vehicle weight rating (GVWR) greater than 10,000 pounds. The more stringent NOx emission standards begin with the 2024 model year engines and become more stringent with 2027 and subsequent model year engines.”

 Extending warranty coverage will necessarily increase the cost of equipment, Swenson noted.

 Advanced Clean Fleet legislation rolled out next in April 2023. ACF requires fleets to gradually replace acquired ZEVs while allowing them to retain ICE vehicles throughout their useful life. Per CARB, useful life is defined “as the later of either: 1) 13 years, beginning with the model year that the engine in the vehicle and was first certified for use by CARB or United States Environmental Protection Agency (U.S. EPA), or 2) the date that the vehicle exceeds 800,000 vehicle miles traveled or 18 years from the model year that the engine in the vehicle was first certified for use by CARB or U.S. EPA (whichever is earlier).”

ACF compliance challenges

In August, EPA held an ACF waiver hearing that included a full day of testimony, comments were also accepted online. One of the companies to participate was Sundance Stage Lines in San Diego. The charter bus company currently uses diesel-powered custom-built buses with a 1,000-mile range and 20-minute refueling time. It has stated opposition to ACF’s zero-emission mandate.

“As BEVs, range is cut to approximately 200 miles (substantially less in cold weather), at which point the vehicle requires a four-hour charge at a dedicated high-voltage charger before it can proceed another 200 miles,” Sundance Stage Lines writes. “Thus, any group attempting to access an area not serviced by either an airport or a nearby charter operator will be forced to make other arrangements. This will have substantial negative effects both on motorcoach operators and the traveling public.”

Among the concerns expressed, Sundance noted that “four major motorcoach manufacturers offer at least one of their models as battery-electric vehicles (BEVs.) In converting the vehicle to run as a BEV, all of the buses have lost over 70% of luggage space because the volume of batteries needed to give the vehicle a reasonable range requires the batteries and the accessories normally driven by the engine be mounted in the underfloor luggage compartments.”

Sundance also pointed out the high cost of ZEVs versus ICE. In the case of motor coaches, the company contends the price “more than doubles, from $650,000 each to over $1,400,000 per bus - a cost per unit over twice as high as any other electric vehicle.”

In its ACF waiver request submitted last November to EPA, CARB writes that “anticipated developments will likely both reduce the costs and increase the number of commercially available ZEVs, including projected decreased costs of batteries and improvements in battery energy density due to economies of scale and increasing pace of technology development and decreased costs of other ZEV components resulting from the projected increased production of ZEVs.” 

Legal battles persist

At least three lawsuits that have emerged to challenge the enforcement of ACF make it California’s most contentious trucking legislation to date. 

The first complaint was filed in October 2023 by the California Trucking Association in the U.S. District Court for the Eastern District of California. The challenge has resulted in the state holding off full enforcement that was originally slated to go into effect on January 1, 2024. CTA’s 32-page complaint argues that the state needs a waiver from the Environmental Protection Agency prior to enforcing ACF since its policies exceed federal mandates.

In response, California put ACF enforcement on hold for most fleets pending receipt of an EPA waiver. CTA noted on its website that waivers typically take 9-12 months to process. The state has been enforcing ACF for public fleets since applying for the waiver in November

“They’re implementing and enforcing ACF for state [California] and local government fleets,” explained Mari Mantle, Cummins Regulatory Affairs Manager. “It's the high priority, federal and then drayage [fleets] that they're waiting on the waiver for.”

CTA’s complaint also highlights concerns of ZEVs relative to internal combustion. Acquisition costs of ZEVs, according to CTA, are “projected to be 2 to 6 times higher than comparable ICE tractors”; ZEV range “is less than half that of an ICE truck”; additional refueling stops needed for ZEVs will require additional time and infrastructure and thus limit more route options historically utilized by ICE trucks.

In April, American Free Enterprise Chamber of Commerce (AmFree Chamber) and Associated Equipment Distributors (AED) filed suit also challenging California’s ACF regulation.

In May, the Nebraska Trucking Association topped a list of plaintiffs that included seventeen states opposing ACF: Alabama, Arizona, Arkansas, Georgia, Idaho, Indiana, Iowa, Kansas, Louisiana, Missouri, Montana, Nebraska, Oklahoma, South Carolina, Utah, West Virginia and Wyoming. Several of these same states joined a suit last year against the Advanced Clean Trucks rule.

Tom Quimby headshot

Tom Quimby

Tom Quimby, On-highway Journalist, has a broad range of experience covering various topics for local and national periodicals. His stories and photos have appeared in The Washington Times and more recently in Commercial Carrier Journal, Overdrive, Hard Working Trucks, Equipment World and Total Landscape Care. Tom has reported on Class 1 – 8 commercial vehicles since 2015. A graduate of the University of Southern California, Tom enjoyed growing up around hot rods, dirt bikes, deserts and beaches near San Diego. He now calls Northwest Florida home.

STEM Project Unites Children in the UK and Uzbekistan

Zoom call with West Park School and the Children's Home

If you ever doubted the ability of young minds to grasp what many adults would consider complex concepts, then you'll be amazed by the achievements of two groups of young children - one in a school in northern England, and the other 4,000 miles away in an orphanage in Uzbekistan.

With the support of Cummins, children ranging from six to twelve years of age have managed to bridge the language, culture, and time divide. They are collaborating with great success on building a basic electric racing car.

The story begins with a visit by Cummins to Rudmash Export Service, which has been representing Cummins in Tashkent, the capital of Uzbekistan, since 2018.

Rudmash has an impressive list of clients in mining, construction, gas, and power generation.

It is also a highly respected supporter of community initiatives, a key focus for Cummins.

During the visit, Amit Kumar, Cummins' Technical Territory Manager for the Commonwealth of Independent States (CIS) region, mentioned the work he was doing with local schools involving the Greenpower Education Trust in the UK.

Amit suggested that Rudmash might consider introducing local children to the fantastic learning opportunity that comes from building an electric car.

The Rudmash executive team loved the idea and reached out to their friends at the local orphanage (Children’s Home 22), about the proposed connection with children from West Park Academy – a primary school near Cummins' manufacturing plant in Darlington, England.

Students at the Children's Home working on the car
The children from Children's Home 22 building the car

Speaking through a translator, Rudmash Sales Manager Mr. Mavlonberdi Akhmedov said there was no hesitation from the orphanage. "Everyone was excited about it," he said. "When we showed them pictures of the car, the children's eyes lit up with interest.

"The only issue we encountered was not being able to involve the older children, but I think Amit has something in his mind for them. It will involve a similar collaboration with a UK school on a larger electric car that they can fit in!"

Over in Darlington, teacher Mr. David Fraser and his group of 9 to 11-year-olds were thrilled at the prospect of working with children from another country.

Students from West Park Academy
The children from West Park Academy

"Before our first session, I showed the children a map of Uzbekistan and explained how the time zones worked," Mr. Fraser said. "Tashkent is four hours ahead of us."

"When they started hearing a different language, they were a little hesitant although still excited. However, towards the end, once they got used to the translation pauses, lots of questions were being asked."

"They adapted very quickly, and every session with the orphanage has become more engaging. The children have greatly benefited from the relationship. It's been a great learning experience."

The car involved in the project is called the Greenpower Goblin G2. It comes as a flat-pack kit including chassis, wheels, steering, disc brakes, a 24V electric motor, and two 12V batteries.

Students at West Park Academy working on the car
The children from West Park Academy building the car

"The project is all about inspiring young children to take an interest in engineering in a fun and innovative way," said Amit Kumar, who earlier this year received special recognition at the North-East England STEM (Science, Technology, Engineering, and Mathematics) Awards for his years of dedication to STEM Education.

"The build introduces children to basic mechanics and electronics and might be the first step on the pathway to a career in engineering or another STEM field.

Mr. Fraser said the children soon started discussing aspects of the car such as frames, brakes, and steering geometry. There was a lively question-and-answer session on different materials that could be used to design and make the car's body. Their last session was about controls and driving.

"There are also other general discussions, as the children are eager to learn more about each other's countries," said Amit, who leads the sessions.

Students at the Children's Home looking at the car drawing
The children from Children's Home 22 talking about a drawing while on a zoom call

Rudmash service engineer Mr. Abdullayev Shakhzod said the children were enjoying the experience of working in teams.

"It's a fantastic new chapter in the history of a place that has a storied past. It was established in 1942 during the Second World War to care for evacuees from all over Eastern Europe. Children of over 40 different nationalities have been cared for by this children's home.

"The home is named Antonina Pavlovna Khlebushkina after the woman who ran it in the early days. She would be so proud of what is happening there today.

"As the summer vacation times differ in the two countries, the West Park school children have already finished building their cars, while the Uzbekistan car is about 40% complete.

"When the children return from their summer camp in September, they will start the rear axle, motor, and electrical components. Then they can take it for a drive," Amit said.

"Just before their summer term ended, the West Park children conducted a demonstration for their new friends in Tashkent. They set up a track and showcased driving the car on it. It was a great success."

Mr. Akhmedov, speaking through a translator, mentioned that the management team at Rudmash was considering how the project could expand beyond the children's home and into schools and youth organizations throughout Uzbekistan.

Mr. Akhmedov praised Cummins for their support of the project. "They have shown great responsibility at every stage and been very proactive, always striving to ensure things are done right.

"This is just the beginning for these children. It's already motivating them to learn more and develop their skills in broader technical applications.

"I would say that this project is not only important for the children's home but also for our city of Tashkent and the Republic of Uzbekistan, as it is nurturing an educational culture that is highly valuable. I can't thank Amit and Cummins enough."

Amit expressed that it's a privilege to help Cummins inspire young people about engineering and science from an early age.

Redirecting to
cummins.com

The information you are looking for is on
cummins.com

We are launching that site for you now.

Thank you.