Bridge to Alternatives: enabling alternative fuel solutions to bridge towards a zero-emission market
As Jacobs approaches its 60th anniversary, we are reflecting on how we got here and where we are going.
In 1930, Clessie Cummins nearly lost his life driving a runaway truck down the Cajon Pass into San Bernardino during his coast-to-coast speed run. He vowed at the time that he would find a way to use a diesel engine as an effective vehicle retarder. This commitment led Clessie to invent the first diesel engine brake commonly referred to as the “Jake Brake.” Today, it seems that the world has a new runaway – vehicle emissions.
In December 2020, Europe’s largest truck manufacturers announced a pledge to end the sale of diesel engines by 2040 – a decade earlier than planned. Daimler, Scania, MAN, Volvo, DAF, Iveco, and Ford will focus on the development of hydrogen, battery technology, and clean fuels.
Ninety years ago, Clessie was advocating for diesel because it was more efficient than gasoline. Now Jacobs is being called to push the limits of diesel efficiency and enable alternative fuel technologies for a zero-emissions future.
The Jacobs team has been working on filling the gaps – Jacobs is helping OEMs to enable alternative fuel solutions to bridge towards a zero-emission market. These include Compressed Natural Gas (CNG), Liquified Natural Gas (LNG), and even technologies including Hydrogen as an alternative fuel. There is no magic button. It will take a series of steps and practical use of our current resources to ultimately move to full electrification.
Advancing the Natural Gas Engine
As OEMs look to reduce emissions and meet environmental regulations, some have turned to Natural Gas engines to meet these objectives while still achieving the needed performance. Jacobs Engine Brakes can be found on Natural Gas engines around the globe. One example is the Cummins ISX12 G engine which has utilized the Jake Brake® since 2013 to extend brake pad life, increase driver confidence, and safely slow vehicles such as the Cascadia® Natural Gas.
While there are some technical challenges with natural gas engines, Jacobs is working to address them. One of those is the engine brake performance. In the conversion from diesel to natural gas, the engine’s compression ratio is significantly reduced, and the turbo is commonly downsized to accommodate a lower air-fuel ratio needed for stoichiometric combustion.
The combination of these two changes can negatively impact engine brake performance by up to 25%. In turn, this will negatively impact the ability of the vehicle to maintain speed on a downhill grade without using the foundation brakes. The increased use of foundation brakes could lead to brake fade and increased brake wear rates. In some markets like Europe, China, and India, it could impact the ability of the vehicle to meet regulation E13C requirements for supplementary retarding and could require a reduction in Max Gross Vehicle weight certification.
There are solutions to this. Jacobs’ High Power Density® (HPD®) system will increase the total vehicle retarding power and reduce dependence on the foundation brakes. These systems will be able to restore or exceed diesel engine retarding performance, allowing increased safety and productivity.
“By using 1.5 stroke HPD technology, we were able to have performance better than the original diesel performance on the natural gas application.”
– Gabe Roberts, Director of Product Development
Learn more about HPD and how it can improve engine braking in Natural Gas applications in Jacobs' Tech Talk video.
Start-Stop for Hybrid Vehicles
Another way for OEMs to close the gap on upcoming emission regulations is to electrify the powertrain. Well-known features such as a Start-Stop function allows for switching off the internal combustion engine during long idle times, traffic lights, etc. This is already commonplace in the passenger car market, but it has been a struggle for the commercial vehicles industry due to the engine size and inertia, which causes an increased load on the starting devices when done often.
To overcome this durability obstacle, Jacobs has developed Active Decompression Technology®, or ADT®. It is acting right on the valvetrain by opening the exhaust valves during engine crank, taking away the compression in the cylinder and, therefore, making start-ups much faster and lighter to do. When the engine has reached its ideal starting rpm, the valves are closed, the injection is synchronized, and the engine comes to life without putting a large load on the starter itself, it's electrical wiring, or battery. Obvious applications include medium-duty trucks and buses, but the technology can also be sized to larger displacement engines, enabling significant fuel savings (and emission reduction as a result). An additional advantage is the smooth start-up of the engine without excessive shake. This helps improve the NVH (noise, vibration, and harshness) characteristics of the complete vehicle and enhances driver comfort.
Extending the Life of the Diesel Engine
In addition to working with alternatively fueled engines, Jacobs is also working to extend the life of the diesel engine by continuing to invent new ways to reduce emissions and decrease consumption of fuel.
Tests in 2018 from three independent research institutions on Jacobs Cylinder Deactivation and Early Exhaust Valve Opening (EEVO) technologies demonstrated Brake Specific Fuel Consumption (BSFC) and after-treatment temperature improvements in all test cycles. The tests also showed significant NOx reductions, especially in the lowest load and cycle work segments.
Today, Jacobs is partnering with universities such as West Virginia University and industry experts like Tula Technology as well as working on OEM SuperTruck programs and others to evaluate the benefits of the new technologies.
Robb Janak, Director of New Technology, will be sharing recent results from CDA and EEVO testing on a U.S. heavy-duty diesel engine at the 8th International Engine Congress.
Hydrogen as an Alternative Fuel
There has been quite some talk about the use of Hydrogen as an alternative fuel. The most well-known application of Hydrogen is within a fuel-cell environment: the Hydrogen is processed in-vehicle to power an electric drive unit. Another angle that many OEMs are exploring today is the use of Hydrogen as a direct replacement for diesel fuel, making use of the existing internal combustion engine architecture. The benefit of that is fewer complex systems on the vehicle, and an infrastructure that is easier to accomplish, in a shorter timeframe. Still in its infancy, Jacobs is working towards enabling this alternative as well, right at the valvetrain, making use of well-proven, durable valvetrain technology from its 60 years of experience.
