What engines are used in cars?

Most cars on the road use internal combustion engines (gasoline or diesel), while a fast-growing share use hybrid systems that pair a combustion engine with one or more electric motors; fully electric vehicles use electric motors rather than engines, and a small niche relies on hydrogen fuel cells powering electric motors. In practice, “what engine is used” depends on the vehicle’s purpose, price, and local regulations, spanning everything from compact three-cylinder gasoline turbos to big diesel engines for trucks, plus increasingly common hybrids and full battery-electric drivetrains.

The main power sources on today’s roads

Modern car powertrains fall into a few clear categories, each with different strengths in efficiency, performance, cost, and emissions. Here is how they break down and where you’re most likely to find them.

• Gasoline (spark-ignition) internal combustion engines: dominant worldwide in small to midsize cars and many SUVs; typically inline-3 or inline-4, often turbocharged.
• Diesel (compression-ignition) internal combustion engines: common in heavy-duty pickups, commercial vans, and some SUVs (especially outside North America) for towing and long-range efficiency.
• Hybrids (mild, full, and plug-in): combine a combustion engine with one or more electric motors to cut fuel use and emissions; popular in city driving and as a step toward electrification.
• Battery-electric vehicles (BEVs): use electric motors powered by batteries; rapidly growing, especially in China, Europe, and coastal U.S. markets.
• Hydrogen fuel-cell electric vehicles (FCEVs): niche models use a fuel cell to generate electricity for motors (e.g., Toyota Mirai, Hyundai Nexo) where hydrogen refueling exists.

Each category serves a different need: combustion engines excel at quick refueling and broad availability, hybrids reduce fuel bills without plug-in habits, and BEVs offer the lowest tailpipe emissions and high performance where charging is practical.

How combustion car engines work

Gasoline vs. diesel

Gasoline engines ignite a fuel-air mixture with a spark plug (spark ignition), favoring smoothness and high-rev power. Diesel engines compress air until it’s hot enough to ignite injected fuel (compression ignition), delivering strong low-rpm torque and superior long-distance efficiency. Emissions technology differs: modern gasoline direct-injection engines often add particulate filters, while diesels use a combination of exhaust gas recirculation, diesel particulate filters, and selective catalytic reduction (urea/AdBlue) to control NOx and particulates.

Engine layouts and sizes

Combustion engines come in multiple cylinder counts and configurations, chosen for cost, packaging, smoothness, and performance. These are the most common layouts you’ll find in cars today, with typical use-cases and examples.

• Inline-three (I3) and inline-four (I4): the workhorses of mainstream cars, usually 1.0–2.5 liters. Many are turbocharged for efficiency and torque (e.g., Ford 1.0 EcoBoost I3, VW 1.5 TSI I4, Toyota 2.0/2.5 Dynamic Force I4).
• Inline-six (I6): prized for smoothness in premium and performance cars and some trucks (e.g., BMW 3.0 B58, Mercedes 3.0 M256; Stellantis “Hurricane” 3.0 twin-turbo I6 in trucks/SUVs).
• V6 and V8: used in larger SUVs, pickups, and performance cars. Examples include Ford’s twin-turbo 3.5 EcoBoost V6, GM’s 5.3/6.2-liter LT-series V8s, and Toyota/Lexus twin-turbo V6s.
• Flat/boxer: horizontally opposed cylinders for a low center of gravity (Subaru flat-4; Porsche 911 flat-6).
• W engines: specialty, ultra-low volume; Bentley ended production of its W12 in 2024.
• Rotary (Wankel): rare today; Mazda revived a single-rotor unit as a generator in the MX-30 R-EV range-extender, not for direct drive.

Automakers match layouts to mission: compact turbos maximize space and economy, straight-sixes deliver refinement, and larger V6/V8 options serve towing and high performance.

Breathing and efficiency tech

To meet power and emissions goals, modern engines rely on airflow and combustion improvements. Turbocharging has largely replaced big displacement, while variable valve timing/lift, direct injection, and advanced combustion cycles squeeze out more efficiency. Notable technologies include:

• Forced induction: turbos dominate; superchargers are rarer. Some brands use electrically assisted turbos for faster response (e.g., Mercedes-AMG on certain 2.0-liter models).
• Combustion cycles: beyond the standard Otto and Diesel cycles, hybrids often use Atkinson/Miller-like timing for efficiency; some engines employ variable compression (e.g., Nissan/Infiniti VC-Turbo) or spark-controlled compression ignition (Mazda Skyactiv-X) to broaden efficiency.
• Cylinder deactivation and start-stop: shut off cylinders or the whole engine under light loads to cut fuel use.
• 48-volt mild hybrid systems: add a belt-driven or integrated starter-generator to assist acceleration and smooth stop-start.

The result is smaller engines that feel bigger, with better drivability and lower emissions than earlier generations.

Electric motors in cars

Fully electric and many hybrid vehicles are propelled by electric motors. While often discussed alongside “engines,” motors are distinct: they convert electrical energy into motion with high efficiency and instant torque. Several motor designs are in use, chosen for efficiency, cost, and rare-earth material needs.

• Permanent-magnet synchronous motors (including interior permanent-magnet designs): widely used for their efficiency and power density by many major EV makers.
• AC induction motors: robust, rare-earth-free options still used in some drive units and performance applications.
• Reluctance-influenced machines (e.g., IPM-SynRM): blend characteristics to reduce rare-earth content while keeping high efficiency, common in hybrids.
• Axial-flux motors: compact, high-torque designs emerging in select high-performance and premium applications.

EVs may use a single motor for simplicity or dual (or more) motors for all-wheel drive and torque vectoring. Modern platforms often operate at 400V or 800V, with silicon-carbide inverters improving efficiency and charging speed. Regenerative braking recovers energy that would otherwise be lost as heat.

Hybrids bridge the gap

Hybrids combine combustion engines with electric assistance to cut fuel consumption and emissions without relying solely on external charging. There are three main flavors, each targeting a different user profile.

• Mild hybrids (usually 48V): a starter-generator assists the engine and smooths stop-start but cannot drive the car alone.
• Full hybrids: can drive short distances on electricity at low speeds; common in city-focused models (e.g., Toyota, Honda, Hyundai systems).
• Plug-in hybrids (PHEVs): larger batteries charge from the grid for meaningful electric-only range; the engine takes over for longer trips. Some, like Mazda’s rotary range extender in the MX-30 R-EV, run the engine purely as a generator.

Hybrids are gaining traction as regulations tighten and buyers seek better economy without committing fully to charging infrastructure.

Hydrogen: fuel cells and experimental engines

Fuel-cell electric vehicles generate electricity onboard by combining hydrogen with oxygen, emitting only water at the tailpipe. The Toyota Mirai and Hyundai Nexo anchor this niche where hydrogen stations exist. Separately, a few manufacturers are testing hydrogen-fueled combustion engines, primarily in motorsport or pilot programs, but these remain experimental and far from mass-market production due to fueling, cost, and efficiency challenges.

Regional and market trends in 2024–2025

Policy and market forces are reshaping what engines automakers build and where they sell them. The U.S. finalized stricter 2027–2032 light-duty emissions rules in 2024, effectively pushing more hybrids and EVs. The EU agreed on Euro 7 provisions that tighten real-world testing and focus more on brake and tire emissions while largely maintaining current tailpipe limits for passenger cars, and its 2035 phaseout of new combustion-only cars includes an exemption path for e-fuels. The UK moved its new ICE sales ban to 2035. California is targeting 100% zero-emission new car sales by 2035. China’s “new energy vehicle” momentum has made EVs and plug-ins over one-third of its new-car market. In parallel, automakers are downsizing and turbocharging gasoline engines, expanding 48V mild hybrids, and increasingly substituting efficient inline-sixes and twin-turbo V6s for older big-displacement V8s; diesel remains important in heavy-duty applications.

Representative engines and where you’ll see them

To give a feel for what’s actually under the hood in 2025, here are common, current examples across segments.

• Mainstream gasoline: Toyota 2.0/2.5-liter Dynamic Force I4; VW/ Audi 2.0 TSI (EA888); Honda 1.5T; Hyundai/Kia Smartstream 1.6T; Ford 1.5–2.3 EcoBoost.
• Performance and premium: BMW 3.0 B58 I6; Mercedes-AMG 2.0 M139 (with hybrid assistance in newer applications); Porsche flat-6 in 911 models.
• Trucks and SUVs: GM 5.3/6.2 LT V8s; Ford 3.5 EcoBoost V6; Stellantis 3.0 “Hurricane” twin-turbo I6; Cummins 6.7 I6 diesel (Ram HD); GM 6.6 Duramax V8 diesel (HD pickups).
• Hybrids and PHEVs: Toyota/Lexus hybrid systems (Atkinson-cycle I4 with e-motors); Honda e:HEV; Hyundai-Kia hybrid and PHEV powertrains; a growing number of turbocharged 4-cyl PHEVs across brands.
• Electric drivetrains: Permanent-magnet-based motors dominate across Tesla, BYD, Hyundai-Kia, VW Group and others, with some models using induction motors; 800V architectures (e.g., in select Hyundai, Porsche, and Audi models) enable faster charging.

Lineups are evolving quickly, but these examples reflect the mainstream choices buyers encounter in showrooms today.

Bottom line

Cars today use a mix of internal combustion engines, hybrids, and fully electric drivetrains. Gasoline and diesel engines remain prevalent, increasingly aided by turbocharging and mild-hybrid tech, while hybrids and BEVs grow as regulations tighten and charging infrastructure spreads. The “right” engine or motor depends on how and where you drive, as well as local fuel prices and policies.

Summary

Most cars still rely on gasoline or diesel engines, often downsized and turbocharged, but hybrids that pair an engine with electric motors are surging, and fully electric cars use motors only. Engine layouts range from compact three- and four-cylinders to inline-sixes, V6/V8s, and niche flat or rotary designs, augmented by technologies like direct injection, variable valve timing, turbocharging, and 48V systems. Electric motors vary by design but increasingly power the market’s growth segments. Policy, infrastructure, and use case ultimately determine which solution fits best in 2025.

What type of motor is used in a car?

Car engines primarily include internal combustion engines (ICE) and electric motors, with hybrid vehicles combining both systems. ICE engines are categorized by their cylinder arrangement: inline (cylinders in a single line), V-type (cylinders in two V-shaped banks), flat/boxer (cylinders horizontally opposed), and W-type (three or more cylinder banks in a W-shaped layout). Electric engines, on the other hand, use electromagnetism to convert electrical energy from batteries into mechanical energy for propulsion. 
Internal Combustion Engines

• Inline Engines: Opens in new tabAlso called straight engines, these have cylinders arranged in a single line. They are common, efficient, and cost-effective for everyday vehicles. 
• V-Type Engines: Opens in new tabCylinders are arranged in two banks that form a “V” shape. V engines are compact and powerful, making them suitable for sports and luxury cars. 
• Flat (Boxer) Engines: Opens in new tabWith cylinders laid out horizontally on opposite sides of the engine, they are also known as horizontally-opposed engines. This design provides a lower center of gravity, enhancing stability. 
• W-Type Engines: Opens in new tabLess common, these engines feature a W-shaped configuration of cylinder banks, offering a compact design for high power output. 

Other Propulsion Systems

• Electric Engines: Opens in new tabThese motors convert electricity stored in batteries into mechanical force, providing zero emissions and quiet operation. 
• Hybrid Engines: Opens in new tabThese combine an internal combustion engine with an electric motor, leveraging the benefits of both technologies for increased efficiency and power. 
• Rotary Engines: Opens in new tabA unique type of ICE that uses a triangular rotor instead of pistons. While compact and offering high power-to-weight ratios, they are less common due to potential issues with fuel efficiency and emissions. 

What type of engine is used in cars?

Petrol and diesel engines are the most common in modern cars. However, alternative fuel engines are also becoming popular. The common car engine types depend on the fuel that powers the motor.

Which is better v4 or V6 engine?

A V6 is “better” than a four-cylinder engine for drivers prioritizing power, torque, and smoothness, especially for heavy loads or spirited driving, while a four-cylinder engine is generally “better” for fuel efficiency and cost, though modern turbocharging has made four-cylinder engines very powerful. The best choice depends on your specific needs and priorities, such as the type of vehicle, driving conditions, and budget. 
Choose a V6 if you need:

• More Power and Torque: Opens in new tabV6 engines typically offer higher horsepower and torque, providing faster acceleration and better responsiveness, especially when carrying heavy loads or in larger vehicles like SUVs and trucks. 
• Smoother and Quieter Driving: Opens in new tabThe inherent design of a V6 engine results in smoother operation and a more pleasant, less “agricultural” sound, making for a more comfortable and refined driving experience. 
• Better Towing and Hauling: Opens in new tabThe increased power and torque of a V6 make it better suited for towing heavy trailers or hauling significant cargo. 
• Less Strain on the Engine: Opens in new tabA V6 engine often operates at lower RPMs, meaning it isn’t working as hard as a smaller engine would for similar tasks, which can contribute to better longevity and reliability. 

Choose a four-cylinder if you prioritize:

• Fuel Economy: Opens in new tabFour-cylinder engines are generally more fuel-efficient, resulting in lower fuel costs compared to V6 engines. 
• Lower Purchase Cost: Opens in new tabVehicles with four-cylinder engines are often less expensive to buy than those with V6s. 
• Lighter Vehicles: Opens in new tabSmaller, compact cars are typically well-suited for four-cylinder engines, offering a good balance of performance and efficiency. 
• Modern Turbocharging: Opens in new tabAdvanced turbocharging technology has significantly boosted the output of many four-cylinder engines, allowing them to provide performance that rivals or even exceeds some naturally aspirated V6s in certain applications. 

Considerations for Both:

• Vehicle Type: Opens in new tabThe appropriate engine size often depends on the vehicle; a V6 is often necessary for the power required by larger trucks and SUVs, while smaller cars often suffice with a four-cylinder. 
• Modern Technology: Opens in new tabThe gap in performance between four-cylinder and V6 engines has narrowed significantly due to advancements like turbocharging and direct injection, so it’s important to look at specific models rather than generalizing based solely on the number of cylinders. 

What does 2000cc mean in a car?

The vehicle’s cubic capacity is broken up into equal shares per cylinder. So, for example, a four-cylinder 2-litre engine, 2000cc, will have 500cc per cylinder.