Staff Motor Thermal Engineer

Rivian; Carson (CA); On-site; USD 137,800 - 172,200; Full time

Job summary

Rivian in California is seeking a Staff Motor Thermal Engineer to lead the thermal architecture and cooling strategy for next-generation electric drive units. You will be the primary liaison for direct‑oil cooling systems, bridging rapid 0D/1D modeling with high‑fidelity 3D CFD, and validating models through testing to meet performance, reliability and efficiency targets.

The role requires expertise in GT-Suite, Simerics/Star-CCM+, Python or MATLAB for data processing, and a track record of

Qualifications

• Education: BS/MS/PhD in Mechanical Eng, Thermal Sciences, or related field.
• 7+ years in EV powertrain lubrication and thermal management.
• Expert-level GT-Suite for transient analysis.
• Extensive experience in Simerics-MP+ or Star-CCM+, focusing on VOF or MPS methods for oil splashing.
• Deep understanding of convective heat transfer in rotating machinery and dielectric oils.
• Experience in multiphase flow or free-surface modeling.
• Scripting in Python or MATLAB for post-processing and workflow automation.
• Knowledge of automated optimization (HEEDS, ModeFRONTIER).
• Experience in lab setup, data collection, and validating designs' performance.
• Fundamental knowledge of electric machines, motor design, and manufacturing.

Responsibilities

• Develop end-to-end lubrication & thermal models from 0D/1D to 3D CFD.
• Lead design and optimization of direct oil motor cooling for end-windings.
• Define lubrication and thermal requirements for motor, inverter, and transmission.
• Design test plans for motor dyno and drive unit validation; correlate with simulations.
• Collaborate to balance power density, efficiency, and thermal management.

Skills

GT-Suite

Amesim

Star-CCM+

Simerics-MP+

Oil cooling

Python

MATLAB

Thermal modeling

EV powertrain

Education

BS in Mechanical Engineering

MS or PhD in Thermal Sciences

Tools

GT-Suite

Amesim

Star-CCM+

Simerics-MP+

Job description

About Rivian

Rivian is on a mission to keep the world adventurous forever. This goes for the emissions‑free Electric Adventure Vehicles we build, and the curious, courageous souls we seek to attract. As a company, we constantly challenge what’s possible, never simply accepting what has always been done. We reframe old problems, seek new solutions and operate comfortably in areas that are unknown. Our backgrounds are diverse, but our team shares a love of the outdoors and a desire to protect it for future generations.

Role Summary

As a Staff Motor Thermal Engineer, you will lead the thermal architecture and cooling strategy for our next‑generation electric drive units. You will be a point of contact for direct‑oil cooling systems, bridging the gap between rapid 1D system modeling, high‑fidelity 3D CFD, correlating and improving models through testing to ensure the motor achieves thermal performance requirements while meeting reliability and efficiency.

Responsibilities

• Develop and maintain end‑to‑end lubrication & thermal models for EV motor, ranging from 0D, 1D system‑level analysis (GT‑Suite, Amesim) to 3D CFD (Simerics‑MP+, Star‑CCM+)
• Lead the design and optimization of direct oil motor cooling, including shaft, rotor, stator, and spray cooling for end‑windings
• Define lubrication and thermal requirements for the motor, inverter, and transmission interface
• Design test plans for motor dyno and drive unit validation, perform test, collect and process data, and correlate simulation results with physical hardware to refine modeling accuracy
• Collaborate with a cross‑functional team to balance the "Golden Triangle" of motor design: power density, efficiency, and thermal management

Qualifications

• Education: BS, MS or PhD in Mechanical Engineering, Thermal Sciences, or a related field
• 7+ years in EV powertrain lubrication and thermal management
• Expert‑level experience in GT‑Suite for transient analysis
• Extensive experience in Simerics‑MP+ or Star‑CCM+, specifically focusing on Volume of Fluid (VOF) or Moving Particle Semi‑implicit (MPS) methods for oil splashing
• Deep understanding of convective heat transfer coefficients in rotating machinery and fluid dynamics of dielectric oils
• Experience in multiphase flow and/or free‑surface modeling
• Scripting skills in Python or MATLAB for post‑processing and workflow automation
• Knowledge with automated optimization (e.g., HEEDS, ModeFRONTIER)
• Experience in lab setup, data collection, and validating thermal and hydraulic designs' performance
• Fundamental knowledge of electric machines, motor mechanical designs, and manufacturing processes
• Self‑motivated with the ability to manage multiple tasks while remaining efficient and accurate
• Flexibility and adaptability in a fast‑paced and dynamic work environment

Pay Disclosure

The salary range for this role is USD 137,800-172,200 for Southern California based applicants. This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting. An employee’s position within the salary range will be based on several factors, including, but not limited to, specific competencies, relevant education, qualifications, certifications, experience, skills, geographic location, shift, and organizational needs. The successful candidate may be eligible for an annual performance bonus and equity awards.

Benefits

We offer a comprehensive package of benefits for full‑time and part‑time employees, their spouse or domestic partner, and children up to age 26, including but not limited to paid vacation, paid sick leave, and a competitive portfolio of insurance benefits, including life, medical, dental, vision, short‑term disability insurance, and long‑term disability insurance to eligible employees. You may also have the opportunity to participate in Rivian’s 401(k) Plan and Employee Stock Purchase Program if you meet certain eligibility requirements. Full‑time employee coverage is effective on their first day of employment. Part‑time employee coverage is effective the first of the month following 90 days of employment. More information about benefits is available at rivianbenefits.com.

Equal Opportunity

Rivian is an equal opportunity employer and complies with all applicable federal, state, and local fair employment practices laws. All qualified applicants will receive consideration for employment without regard to race, color, religion, national origin, ancestry, sex, sexual orientation, gender, gender expression, gender identity, genetic information or characteristics, physical or mental disability, marital/domestic partner status, age, military/veteran status, medical condition, or any other characteristic protected by law. Rivian is committed to ensuring that our hiring process is accessible for persons with disabilities. If you have a disability or limitation, such as those covered by the Americans with Disabilities Act, that requires accommodations to assist you in the search and application process, please email us at [e-mail].