Stanadyne, a global fuel and air management systems supplier, has participated in a research program that tested the feasibility of liquid propane gas (LPG) direct injection as a viable alternative fuel delivery option for medium-duty (class 3 to 7) engines. The research program was conducted by Katech Engineering and funded by the Propane Education & Research Council (PERC). The full research program performance report has been published on the PERC website’s Engines/Fuels Studies page.
The research program centers around the development and testing of a robust direct injection fuel system using new hardware and software inhibitor technologies to remove vapor lock barriers specific to propane. The test results showed these technologies enabled stable operation of the engine during hot-start, cold-start, hot-soak, and hot-idle conditions. The research also showed robust performance over a 250-hour durability test using a customized duty cycle.
“Overall, the proposed fuel system with in-house developed vapor lock inhibitor hardware and software addressed the design limitations faced by other LPG direct injection applications,” said Katech Engineering Lead R&D / Motorsport Engineer Eric Suits, who was the research program’s principal investigator. “The research results prove the efficacy of liquid propane as a fuel for direct injection, while addressing the previous design limitations.”
The research team worked directly with Stanadyne to design LPG-specific fuel pumps and injectors. The test engine was updated with the Stanadyne components and operated on LPG direct injection. The results of this propane configuration were able to meet all power and torque metrics of the baseline gasoline engine.
“Limited modifications were made to the test engine,” said Stanadyne Chief Engineer Srinu Gunturu. “Along with Stanadyne’s new LPG direct injection pump and injectors, the proposed technology shows a high level of feasibility for cost-effectiveness and widespread production and commercialization.”
Using LPG – particularly renewable propane produced as a byproduct of renewable diesel – has tremendous implications for cleaner propulsion, especially for the hard-to-electrify medium and heavy-duty vehicle market. LPG offers an approximate five to 10 percent reduction in carbon dioxide emissions and has almost no nitrogen oxide emissions compared to traditional diesel fuel. In addition, LPG does not require a particulate filter, has a lower total cost of ownership compared to other fuels on the market, and generates fewer carbon emissions with minimum engine adjustments. Renewable propane has a carbon intensity that is four times lower than that of conventional diesel.
“The partnership between Stanadyne, Katech, and PERC developed a first-of-its-kind propane direct injection system for medium and heavy-duty applications that will significantly improve engine efficiency and reduce emissions with low-carbon and renewable propane,” said PERC President and CEO Tucker Perkins. “We see this innovation as an enabling technology for a new generation of clean and efficient on-road, off-road, and power generation propane engines.”
The 98-page Katech and PERC Research Program Performance Report details all aspects of the two-year assessment of liquid direct injected fuel systems for propane engines. The full report can be downloaded free of charge here. For more information about Stanadyne’s innovative direct injection fuel pump and injector system, click here.
