Capstone Turbine Corp. has secured a patent for a cleaner fuel injector system on its microturbines, the company announced Monday. The Chatsworth company, which makes turbines for energy and heat generation, said the U.S. Environmental Protection Agency has raised its emission standards for electricity-producing turbines, and the new fuel injector enables its products to meet the Tier 4 requirements, the ultra-low emissions standard. “Capstone’s product development group is doing an excellent job moving the technology forward in meeting continuously lower global emissions standards without the crutch of using emissions after-treatment devices, which increase the first cost and the total system complexity and inherently lower reliability,” Darren Jamison, Capstone’s chief executive, said in a statement. The new patent raises Capstone’s total portfolio to 127. Capstone shares closed Monday down 3 cents or 2.1 percent to $1.39 on the Nasdaq.