Mainspring Energy

Senior Mechanical Design Engineer - Fuel Systems

Menlo Park, CA, US

In-personFull time roleSenior Level

22 days ago

About the Job

Company Overview

Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable onsite power generator, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options like engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid-scale operations. The Mainspring Linear Generator is fuel flexible, ramps up and down to meet demand, and utilizes a flameless technology with near-zero NOx emissions.

Backed by top-tier investors such as Khosla Ventures, Bill Gates, American Electric Power, and Lightrock, Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and we’re quickly scaling for international expansion.

Inspired by our vision of the affordable, reliable, net-zero carbon grid, Mainspring is rapidly expanding within the $816B global electricity equipment market, and we’re hiring the best talent to meet growing customer demand around the globe. We welcome a broad range of backgrounds, experiences, and talents to bring fresh perspectives and ongoing innovation to our customers.

We are looking to build relationships with people who share our values:

Pragmatic Optimism. Building a new category of world-class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. The challenges that arise are opportunities for growth.

Excellence without Ego. We bring expertise and commitment to creating the best customer experience, from sales to deployment and service, just as we apply deep technical rigor to building and delivering world-class products. We strive for excellence and behave as leaders with the humility to acknowledge our challenges, both collectively and as individual contributors.

Proactive Collaboration. The integration and cross-disciplinary nature of Mainspring’s business requires intentionally seeking out others who bring different skills, perspectives, and priorities. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers.

More information can be found at www.mainspringenergy.com

We are seeking a Fuel Systems Mechanical Engineer to design, develop, and test fuel transport and control systems for generator power systems compatible with multiple fuel types, including, natural gas, biogas, and alternative fuels. In this role, you will lead the design, validation, and optimization of fuel delivery and control components, ensuring performance, reliability, and regulatory compliance. You will work cross-functionally with mechanical, electrical, and controls engineers to integrate fuel systems into generator platforms.

Core Responsibilities

Design, integrate, and optimize fuel transport and control systems, including, valves, filters, sensors, and associated piping.
Develop multi-fuel compatibility solutions, ensuring reliable transport and operation of generator reaction controls and system safety.
Conduct fluid flow analysis and system modeling to optimize fuel system performance.
Define and execute test plans to validate system functionality under various operating conditions (pressure, temperature, flow, vibration, and durability.
Collaborate with manufacturing and supply chain teams to transition designs from prototype to production.
Conduct failure analysis and implement design improvements based on testing and field performance.
Work with internal regulatory experts to ensure compliance with industry standards (NFPA, SAE, EPA, UL, etc.).
Document technical specifications, system schematics, BOMs, and validation reports.
Participate in design reviews and contribute to continuous improvement initiatives.
Provide technical guidance to junior engineers and cross-functional teams.

Qualifications

Degree in Mechanical Engineering, Aerospace Engineering, or a related field from an accredited institution.
BS + 6 years or MS + 5 years of relevant industry experience
Fluent in fluid dynamics, thermodynamics, and fuel properties.
Experience with fuel systems in generator, aerospace, or automotive applications.
Hands-on expertise in CAD software (SolidWorks, Creo) and product life cycle management.
Experience with fuel delivery components, including pipe and tube standards, valves, regulators, and filtration systems.
Familiarity with regulatory requirements for multi-fuel systems.
Structured approach to analytical, troubleshooting, and problem-solving skills.
Ability to manage multiple projects in a fast-paced environment and work independently or in a team setting.
Excellent communication and documentation skills.

Preferred Qualifications

Experience with dual-fuel or alternative fuel systems.
Background in power generation or off-highway equipment.
Knowledge of engine control units (ECUs) and fuel system integration.
Experience with manufacturing processes for fuel system components.

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

About the Company

Mainspring Energy

Menlo Park, CA, USA

251-500

<p class="text-steel f-b1 md-max:mb-d">At Mainspring we believe the fastest path to the net-zero carbon grid is vastly increasing the amount of solar and wind power while building a supporting clean energy system that ensures affordability and multi-day, cross-season resilience. Getting there requires flexible, scalable, local technologies that can adapt to the shifting grid landscape – including the transition from natural gas to renewable fuels like biogas, green ammonia, and green hydrogen.</p> <div> <p class="text-steel f-b1">The Mainspring Linear Generator delivers an unmatched level of flexibility for the transition ahead. It’s local so you can site where power is needed, it’s dispatchable so you can ramp up and down to complement renewables, and it’s fuel-flexible so you can operate on the cleanest fuels available today and in the future. Our products are already at work at Fortune 500 customer sites, accelerating the arrival of the net-zero carbon grid.</p> </div>

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