How Many Types of Automobile Engines Are There?

There isn’t a single fixed number, because “type” depends on how you classify engines; however, by power source, five main powertrain types dominate modern road cars: gasoline internal-combustion engines (ICE), diesel ICE, hybrids, battery-electric vehicles (BEVs), and hydrogen fuel-cell electric vehicles (FCEVs). Beyond these, engineers and enthusiasts also group engines by combustion cycle, cylinder layout, induction (turbo/supercharging), fuel, cooling, and even niche concepts like rotary or turbine designs.

Why the Count Varies

Ask an engineer “how many engine types are there,” and the answer will hinge on the lens you choose. Automakers, regulators, and buyers often talk in terms of the energy source powering the wheels. Powertrain designers further divide engines by how they burn fuel, how air gets in, how cylinders are arranged, and what fuels they use. Each lens yields a different tally—hence no universal number.

The Five Primary Powertrain Types on the Road Today

Most contemporary passenger vehicles fall into five headline categories based on how they are powered. This framing is the clearest way to count “types” for today’s market and policy conversations.

• Gasoline ICE (spark-ignition): Conventional engines burning petrol, the most common globally.
• Diesel ICE (compression-ignition): Higher efficiency and torque, prevalent in trucks and some SUVs, with shrinking share in light-duty cars in many regions.
• Hybrids: Combine an ICE with one or more electric motors; includes mild hybrids (MHEV), full hybrids (HEV), and plug-in hybrids (PHEV).
• Battery-Electric Vehicles (BEV): Fully electric, powered by batteries and electric motors only.
• Hydrogen Fuel-Cell Electric Vehicles (FCEV): Generate electricity onboard from hydrogen, emitting only water vapor.

Together, these five categories describe the vast majority of vehicles sold worldwide today, though their market shares vary widely by region and use case.

Internal-Combustion Subtypes: How Engineers Slice the Pie

By combustion cycle and valve strategy

Combustion timing and thermodynamic cycles lead to functionally distinct ICE “types,” even when they burn the same fuel.

• Otto cycle (spark-ignition): The classic gasoline engine cycle used in most petrol cars.
• Diesel cycle (compression-ignition): Relies on high compression to ignite fuel, delivering strong efficiency under load.
• Atkinson cycle: Uses valve timing to extend expansion relative to compression; common in hybrids for efficiency.
• Miller cycle: Similar to Atkinson with boosted induction; pairs well with super/turbocharging.
• HCCI/SPCCI: Homogeneous charge compression ignition (and Mazda’s SPCCI variant) blend SI and CI traits for efficiency and low NOx.
• Two-stroke vs. four-stroke: Four-stroke dominates cars; two-stroke appears mainly in small engines and a few historical/experimental autos.

These cycles each trade off power density, fuel economy, and emissions, which is why automakers mix and match them with electrification and boosting.

By cylinder layout

Mechanical packaging and balance define another way to categorize engines: the physical arrangement of cylinders.

• Inline (I3, I4, I5, I6): Simple and space-efficient; I3 and I4 are common, I6 resurged with modern packaging.
• V engines (V6, V8, V10, V12): Compact length with good balance; widespread in performance and trucks.
• Flat/boxer (H4, H6): Low center of gravity; used by Subaru and Porsche.
• W engines (W8, W12, W16): Packaging of multiple banks; rare, seen in high-end or halo models.
• Rotary (Wankel): No pistons; compact and smooth, historically Mazda’s specialty, now reappearing as range extenders.

Layout affects vibration, weight distribution, vehicle design, and even crash structures, shaping what engines fit which cars.

By aspiration (air handling)

How an engine breathes profoundly influences performance and efficiency, creating practical “types” used across segments.

• Naturally aspirated (NA): Air drawn in at atmospheric pressure; linear response, simpler hardware.
• Turbocharged: Exhaust-driven compressor increases air mass for more power from smaller engines.
• Supercharged: Crank-driven compressor offers immediate boost, often in performance or towing applications.
• Twincharging: Combines turbo and supercharger for broad torque and response.

Downsized, turbocharged gasoline engines have largely replaced larger NA units in many markets due to efficiency and emissions targets.

By cooling and ignition method

Cooling medium and ignition type also mark common distinctions you’ll see in spec sheets and engineering literature.

• Liquid-cooled vs. air-cooled: Liquid dominates modern cars; air-cooled persists mostly in motorcycles and classics.
• Spark-ignition (SI) vs. compression-ignition (CI): SI for gasoline; CI for diesel and some alternative fuels.

These attributes influence durability, emissions control strategies, and NVH (noise, vibration, harshness).

Alternative and Niche Engine Concepts

While not mainstream, several engine types have played notable roles historically or in specialized applications.

• Rotary/Wankel: Compact and smooth; limited by sealing and emissions, now returning as compact range extenders in some EVs.
• Gas turbines: Excellent power-to-weight but poor drivability and efficiency at road speeds; mainly experimental.
• Compressed-air engines: Zero tailpipe emissions but low energy density; prototypes and city microcars only.
• Steam: Early automotive history and hobbyist builds; not part of modern production fleets.
• Hydrogen ICE: Burns hydrogen in modified CI or SI engines; being piloted in motorsport and heavy-duty trials.
• Range-extender engines: Small ICE used purely to generate electricity in series-hybrid EVs.

These categories broaden the definition of “engine type,” but sales volumes remain tiny compared with mainstream powertrains.

Fuel Choices That Create Further “Types”

Even within a given engine architecture, fuel selection can effectively define another type, with distinct performance and emissions profiles.

• Gasoline (E0–E10): Standard petrol blends; higher octane fuels support higher compression and boost.
• Diesel: High energy density; compatible with aftertreatment for modern emissions standards.
• Ethanol/flex-fuel (E85): Higher octane, lower energy density; common in Brazil and select markets.
• LPG and CNG: Lower CO2 per unit energy and cleaner combustion; popular in taxis and fleets in some regions.
• Biodiesel/HVO: Renewable diesel substitutes usable in many modern diesel engines.
• Synthetic e-fuels: Drop-in hydrocarbons made from green hydrogen and captured CO2; niche pilots, with the EU allowing a post-2035 exception for e-fuel-only ICE.
• Hydrogen: Used in FCEVs or in emerging hydrogen ICE prototypes, especially for heavy-duty use cases.

Fuel infrastructure, cost, and policy support largely determine which of these become practical “types” in any given market.

How Policy and Markets Shape the Mix in 2025

As of 2025, BEVs are the fastest-growing segment globally, propelled by stricter emissions rules and maturing battery supply chains. Hybrids, especially full and plug-in variants, are surging as a bridge technology, offering efficiency without full reliance on charging infrastructure. Diesel’s share in light-duty cars has declined sharply in Europe post-2015, though it remains vital in heavy-duty transport. Hydrogen FCEVs are available but limited by sparse fueling networks, while hydrogen ICE is under active development in motorsport and heavy commercial trials. The EU’s 2035 zero-CO2 target for new cars includes a carve-out for vehicles running exclusively on certified e-fuels, keeping a narrow lane open for future ICE. Regional variations remain stark, with China and Europe leading EV penetration and North America seeing robust growth in both BEVs and hybrids.

Bottom Line

There’s no single authoritative count of “engine types.” For everyday purposes, five primary power sources describe the modern landscape: gasoline ICE, diesel ICE, hybrids, BEVs, and hydrogen FCEVs. Within and beyond those, numerous engineering subtypes—cycles, layouts, induction methods, and fuels—create many more legitimate ways to classify what’s under the hood.

Summary

Engine “type” is defined by context. In today’s market, five major powertrain categories dominate, but engineers subdivide them by combustion cycles, cylinder layouts, air handling, and fuels. Policy, infrastructure, and technology trends in 2025 are accelerating BEVs and hybrids, narrowing diesel’s role in light-duty vehicles, and keeping options open for hydrogen and synthetic-fuel pathways.

What is the most common engine in cars?

The most common engines in cars are petrol/gasoline inline-four engines, which are popular for their compact size, efficiency, and balance of power and economy, especially in smaller vehicles. For more powerful vehicles and larger trucks, V8 petrol engines are very common, particularly in the United States. Other common engine types include diesel engines, which are prevalent in many parts of the world and for larger commercial vehicles, and hybrid engines, which combine a traditional combustion engine with an electric motor for improved fuel efficiency.
 
By Fuel Type

• Gasoline (Petrol) Engines: Opens in new tabThese are the most prevalent in passenger cars worldwide. 
• Diesel Engines: Opens in new tabWhile less common in the US for passenger cars, they are a major type of engine in many parts of the world and are widely used in trucks and larger vehicles. 
• Electric Engines (EVs): Opens in new tabThese are becoming increasingly common as the market shifts toward alternative power sources. 
• Hybrid Engines: Opens in new tabThese combine gasoline or diesel engines with electric motors, and are a common choice for drivers seeking better fuel economy and lower emissions. 

By Configuration

• Inline-Four (Straight-Four) Engines: Opens in new tabThe most common layout for passenger cars, known for being compact, relatively fuel-efficient, and offering a good blend of power and refinement. 
• V6, V8, and V12 Engines: Opens in new tabV-configuration engines are very common in mid-size to larger vehicles, with V8s being particularly popular in the US for their power and longevity. 
• Flat (Boxer) Engines: Opens in new tabWhile less common than inline or V engines, these are found in some performance and luxury vehicles. 

What is the 3 type of engine?

ATC Blog ● Engine Type #1: Gas Engines . The traditional engine type that still lives under the hood of countless vehicles on the road today is the internal combustion gasoline engine .Engine Type #2: Hybrid and Electric Engines .Engine Type #3: Diesel Engines .

How many types of engines are there in a car?

There are broadly four main types of modern car engines: Internal Combustion (Petrol and Diesel), Hybrid, Electric, and Fuel Cell. These types are then further categorized by their fuel source (like petrol, diesel, or electricity), their internal configuration (such as inline, V, or flat cylinders), and whether they are naturally aspirated or use a turbocharger.
 
Primary Engine Types

• Internal Combustion Engines (ICE): These burn fuel inside the engine to create power. 
  • Petrol (Gasoline) Engines: The most common type of ICE, using spark ignition to burn fuel. 
  • Diesel Engines: Known for high torque and fuel efficiency, these engines use compression ignition. 
• Hybrid Engines: These combine a traditional internal combustion engine with an electric motor, offering improved fuel economy and reduced emissions. 
• Electric Motors: Powering all-electric vehicles (EVs), these engines use electricity stored in a battery and produce zero tailpipe emissions. 
• Fuel Cell Vehicles: Less common, these vehicles use hydrogen to generate electricity via a fuel cell, which then powers an electric motor. 

Other Classifications

• By Cylinder Configuration: How the cylinders are arranged affects power and size. 
  • Inline/Straight: Cylinders are in a single row. 
  • V-Type: Cylinders are arranged in two banks forming a “V” shape. 
  • Flat (Boxer): Cylinders are arranged horizontally and oppose each other. 
  • W-Type: A more complex configuration combining VR banks, rarely used. 
• By Aspiration: How air enters the engine. 
  • Naturally Aspirated: Relies on atmospheric pressure to draw in air. 
  • Turbocharged: Uses a turbocharger to force more air into the engine for increased power. 
• By Fuel Injection: How fuel is delivered to the engine. 
  • Multi-Point Fuel Injection (MPFI): Used in petrol engines for precise fuel delivery. 
  • Common Rail Direct Injection (CRDi): Found in diesel engines for highly precise fuel delivery. 

Which is the best engine in a car?

There is no single “best” engine; “best” depends on your priorities, such as reliability, performance, or fuel efficiency. Highly-regarded engines for reliability include Toyota’s 2JZ and the 22R/RE, along with Honda’s K-Series and B-Series engines, known for their durability and ease of maintenance. For performance, legendary engines like the Toyota 2JZ-GTE, Nissan RB26DETT, and the Ferrari 3.9-litre Twin-turbo V8 are praised for their speed and engineering. Engines like the Hyundai Ioniq’s 1.6-liter hybrid system, on the other hand, are noted for their fuel efficiency. 
For Reliability

• Toyota 2JZ: Opens in new tabA robust and widely respected engine for its durability and long life, according to Carro. 
• Honda K-Series (K20/K24): Opens in new tabKnown for versatility, reliability, and upgrade potential, making them a favorite for performance and enthusiasts. 
• Toyota 22R/22RE: Opens in new tabSimple, rugged, and nearly bulletproof, these old-school Toyota motors are built to last and are easy to maintain. 
• Mercedes-Benz OM617: Opens in new tabA durable and long-lasting diesel engine known for its simple, heavy-duty components. 

For Performance

• Ferrari 3.9-litre Twin-turbo V8: This engine won the International Engine of the Year award multiple times for its outstanding performance and power. 
• Toyota 2JZ-GTE: A legendary engine praised for its reliability and performance, capable of handling significant power. 
• Nissan RB26DETT: A high-performance engine famous in the racing world for its speed and power. 
• Mercedes-AMG M139: A powerful and high-revving engine known for its impressive performance. 

For Fuel Efficiency 

• Hyundai Ioniq (1.6-liter Hybrid): This engine-hybrid system offers exceptional miles-per-gallon, making it one of the most fuel-efficient options available.

Why “Best” is Subjective

• Your Driving Needs: Opens in new tabIf you need a reliable daily driver, a Toyota or Honda engine might be best, while a performance enthusiast might look for a Ferrari or Nissan engine. 
• Maintenance: Opens in new tabSome engines, like the Toyota 22R/RE, are praised for being simple and easy to work on, reducing maintenance costs over time. 
• Longevity: Opens in new tabSome engines are built to last for hundreds of thousands of miles with minimal issues, while others are designed for peak performance.