THE AFFAIR OF THE ENERGY AND THE ENGINE: WHY WHAT POWERS THE ENGINE MATTERS MORE THAN EVER

 

You can’t talk about engines without talking about energy. 

Fuel isn't just a refill, it's the defining ingredient.

The type of energy you use doesn’t just affect performance or cost. It shapes:

• The internal design of the engine
• The gear systems that go with it
• Its lifespan, sound, feel, and even its political implications

In this post, we’ll look at how different energy sources, such as gasoline, electricity, steam, compressed air, and more, often influence the engines they power. In addition, the reason why, in a tinkerer’s eyes, the fuel is just as fascinating as the fire.

Petroleum: Explosions in a Controlled Cage

The classic combustion engine. Air + fuel + spark = controlled chaos.

How it shapes the engine:

• High-speed rotation, high torque (especially in the mid-to-high RPM range)
• Requires pistons, crankshaft, timing gears, camshafts and valves to be all synced perfectly
• Heat is a major challenge, and therefore cooling systems are essential

Pros:

• Portable, high energy density
• Tried and tested, therefore, huge infrastructure

Cons:

• Pollution, noise, moving parts wear out
• Dependent on fossil fuel availability

🧠 Why it matters to tinkerers: Internal combustion engines (ICEs) are full of systems, from fuel injection, spark timing, exhaust scavenging and many more. There’s endless room to experiment, modify, and restore.

Electricity: Power With Precision

Electric motors are changing the game. Quiet, smooth, instant torque.

How it shapes the engine:

• No combustion = no pistons, no valves
• Rotation comes directly from magnetic fields (brushless or brushed)
• Often paired with simple gear reduction or direct drive

Pros:

• Near-instant torque
• Silent, clean, efficient
• Fewer moving parts

Cons:

• Range anxiety (for vehicles)
• Battery size, weight, and cost
• Cooling needed for performance motors

🧠 Why it matters to tinkerers: Electric motors simplify the drivetrain, which means, no exhaust, no oil, no timing. However, they challenge us in new areas, battery management, thermal design, and control electronics.

Steam: Pressure Before Pistons

Steam powered the industrial revolution. Today, it’s a niche, but however, it is a fascinating, power source, to reflect and look at.

How it shapes the engine:

• Uses external combustion: heat water → steam → pressure moves a piston or turbine
• Requires a boiler, pressure valves, and a control system

Pros:

• Works with multiple fuels (wood, coal, alcohol, solar thermal)
• Excellent torque characteristics at low RPM

Cons:

• Bulky, slow to start
• Heat and pressure hazards

🧠 Why it matters to tinkerers: Building or restoring a steam engine means mastering thermodynamics, metallurgy, and fluid control. Great for hands-on learners and historical engine fans.

Compressed Air: Clean and Fast (for Short Bursts)

Compressed air engines are lightweight, clean, and surprisingly powerful, for short durations.

How it shapes the engine:

• Similar to steam engines in motion, pressure drives a piston
• Needs a tank, regulator, and valves
• Often used in tools, stunt vehicles, or educational kits

Pros:

• No combustion, no pollution
• Simple mechanics

Cons:

• Limited energy storage
• Not suitable for long-distance or high-torque needs

🧠 Why it matters to tinkerers: Great for DIY builds and learning control systems. You can run compressed-air cars or engines indoors without the hazards of fuel or electricity.

Human Power, Wind, and Solar: Non-Standard Inputs

Not every engine has to roar or spin. Some are designed around alternative inputs:

• Pedal-powered generators — simple crank + gear + alternator
• Wind-powered devices — gear trains matched to wind speed
• Solar engines — thermal or photovoltaic driven

These aren’t always practical for heavy machines, but they prove that engines can be designed around whatever energy nature gives you.

🧠 Why it matters to tinkerers: These builds teach mechanical efficiency and creative thinking. You're not just choosing an engine, you're shaping one around a resource.

One Energy, Many Designs

Here’s what’s amazing, even with the same energy source, you get wildly different engine designs.

Take electricity:

• Powering a drone uses tiny brushless motors spinning at high RPM
• Powering an e-bike needs torque-heavy hub motors
• Powering a robotic arm might use stepper motors with gear reduction

The purpose and the power source shape each other. As a builder, your job is to balance both.

Tinkerer’s Exercise: Compare Two Engines

Pick two different energy types, let's say, a gas-powered lawn mower and an electric scooter motor.

• Sketch out their main components.
• List what they need to function (fuel, cooling, control).
• Compare how they deliver motion, torque, and complexity.

This is how you start to think like an engine designer.