What Is the Study of Engines Called?

The study of engines is called thermodynamics, a core area within mechanical engineering that focuses on how energy is converted to work and heat. In practice, this knowledge is applied through specialized fields such as power and propulsion engineering, internal combustion engine engineering, and gas-turbine engineering, which together cover the theory, design, and performance of engines in cars, aircraft, ships, and power plants.

Why Thermodynamics Is the Core Discipline

Engines—whether piston engines, gas turbines, or steam cycles—are heat engines: they transform chemical or thermal energy into mechanical work. Thermodynamics provides the laws and models that predict how efficiently this transformation can occur, what losses are inevitable, and how design choices affect performance. From Carnot’s ideal limits to real-world cycle analysis, thermodynamics underpins how engineers size components, set compression ratios, manage heat transfer, and evaluate fuels.

Key Concepts That Underpin Engine Study

The following concepts are foundational for understanding how engines work, how their performance is measured, and where efficiency gains or losses occur.

1. First Law of Thermodynamics: Conservation of energy governs fuel-to-work conversion and heat balance.
2. Second Law of Thermodynamics: Entropy and irreversibility set the upper bounds on efficiency.
3. Carnot Efficiency: The theoretical maximum efficiency determined by hot and cold reservoir temperatures.
4. Thermodynamic Cycles: Idealized and real cycles such as Otto (spark-ignition), Diesel (compression-ignition), Atkinson/Miller (variable expansion), Brayton (gas turbines), and Rankine (steam plants).
5. Exergy and Entropy Generation: Tools for pinpointing where useful work potential is lost in components like compressors, combustors, cylinders, and turbines.

Together, these principles allow engineers to model engine behavior, optimize designs for power and fuel economy, and assess trade-offs among performance, emissions, and durability.

Where It Sits in Engineering Education and Practice

Thermodynamics is taught as a foundational sequence in mechanical engineering, followed by courses and labs in heat transfer, fluid mechanics, combustion, and machine design. Professional practice narrows into domains like automotive powertrains, aerospace propulsion, marine and stationary power, and energy systems, where engineers integrate thermodynamic theory with materials, controls, and manufacturing.

Related Subfields and Specializations

Engine-focused work often spans multiple specialties, reflecting the complexity of modern power systems and the drive for higher efficiency and lower emissions.

• Internal Combustion Engine Engineering: Design and analysis of spark- and compression-ignition engines, including fuel systems and aftertreatment.
• Gas-Turbine and Propulsion Engineering: Axial/centrifugal compressors, combustors, turbines, and performance mapping for aircraft and power generation.
• Power Engineering/Thermal Power: Steam cycles, combined-cycle plants, waste-heat recovery, and cogeneration.
• Automotive Powertrains: Integration of engines with transmissions, hybrid systems, and emissions control.
• Aerospace Propulsion: Turbojets, turbofans, ramjets/scramjets, and emerging hydrogen or SAF-based systems.
• Combustion Science: Chemical kinetics, flame dynamics, knock, soot/NOx formation, and low-temperature combustion modes.
• Fluid Mechanics and Heat Transfer: In-cylinder flows, turbulence, cooling, and thermal management.
• Electrified Powertrains (Related, Not “Engines”): Electric motors and power electronics fall under electrical engineering and electromechanics; the term “engine” typically denotes a heat engine.

While these areas differ in tools and applications, they share thermodynamics as the common analytical framework for efficiency, performance, and emissions.

Terminology and Common Confusions

In engineering usage, “engine” usually means a heat engine (e.g., piston engine, gas turbine), while “motor” often refers to an electric machine. Studying engines centers on thermodynamics, supported by combustion, fluids, and heat transfer; studying electric motors primarily involves electromagnetics, power electronics, and control. Terms like “enginology” are not standard in academia or industry; the accepted domains are thermodynamics and mechanical engineering.

Summary

The study of engines is thermodynamics, practiced primarily within mechanical engineering and its specializations in power and propulsion. From thermodynamic laws to real-world cycles, this discipline provides the theoretical and practical basis for designing efficient, cleaner, and reliable engines across transportation and energy sectors.

What are the four types of mechanical engineering?

There are not four specific types of mechanical engineering, but rather a broad field with many specializations, often grouped into traditional areas like thermodynamics and heat transfer, mechanics of materials, fluid mechanics, and design and manufacturing. Modern areas of specialization include robotics, automotive design, aerospace, and HVAC, focusing on applying these core principles to specific industries and technologies. 
Here are some examples of common areas within mechanical engineering:

• Thermodynamics and Heat Transfer: Opens in new tabStudies energy, its movement, and transformation, forming the basis for many systems like power plants, refrigeration, and HVAC. 
• Mechanics of Materials & Structures: Opens in new tabInvestigates how solid bodies behave under forces and stress, which is crucial for designing everything from bridges to artificial limbs. 
• Fluid Mechanics: Opens in new tabFocuses on the behavior of liquids and gases, with applications in areas like water filtration, gas flow, and the design of aircraft and vehicles. 
• Design and Manufacturing: Opens in new tabEncompasses the creation of machinery and products, including aspects of machine design, fabrication, and manufacturing processes. 

In addition to these core areas, many mechanical engineers specialize in broader applications: 

• Automotive Design: Designing and developing vehicles.
• Robotics: Developing automated systems and robots.
• Aerospace Engineering: Designing systems for air and space.
• Mechatronics: A hybrid field combining mechanical engineering with electronics and computer control.
• Biomechanics: Applying mechanical engineering principles to biological systems.
• Systems and Controls: Designing and managing complex systems and their control mechanisms.

What are engine designers called?

A mechanical engineer specializes in designing, building, and repairing complete mechanical systems and machines and their components. These systems and machines are usually intended to fulfill a particular function or purpose, such as a piece of medical equipment, an automotive engine, or an aeronautical component.

What engineering studies engines?

Mechanical Engineering
Mechanical Engineering
Mechanical engineering involves the design, development, and maintenance of mechanical systems, from engines and machines to heating and cooling systems. Mechanical engineers use principles of physics and materials science to innovate and improve devices essential to modern life.

What is the study of automobiles called?

Automobile engineering. Automobile engineering is a branch study of engineering which teaches manufacturing, designing, mechanical mechanisms as well as operations of automobiles. It is an introduction to vehicle engineering which deals with motorcycles, cars, buses, trucks, etc.