Hybrid Engine

Step by step guide on how a hybrid engine works, this information pertains to all gasoline/electric hybrid vehicles.

Step 1 - Contrary to popular belief, a hybrid drivetrain is similar to a conventional vehicle, in fact, the internal combustion engine portion of the vehicle is almost exactly the same. The transmission of a hybrid vehicle is where the difference lies via the electric motor intergraded into its inner workings.

Hybrid Gasoline Engine

Step 2 - One of the main differences between a conventional engine and a hybrid gasoline engine is the absence of a serpentine belt to drive accessories usually handled by the gasoline engine.

No Serpentine Belt

Step 3 - Because the hybrid engine needs coolant to circulate to cool, an electric water pump has been designed to operate on electric power.

Electric Water (Coolant) Pump

Step 4 - The air conditioner has been traditionally powered by the engine which has been replaced by an electrically driven pump which operates while the gasoline engine is not running.

Electric Air Conditioner Compressor

Step 5 - Hybrid engines utilize an electronic throttle control which is controlled by the computer similar to conventional vehicles.

Throttle Actuator

Step 6 - An electric motor intergrated into the transmission serves to propel the vehicle while in electric mode. This motor also acts as the combustion engine starter and charger much like the alternator of a conventional car.

Electric Motor Cutaway

Helpful Information

A computer system is used to help choose which engine will be more efficient at any given time. In most cases the electric motor will start the vehicle in motion, while the gasoline engine will pick up the load at higher speeds. While in braking mode, the electric motor transforms into a charging device which is used to charge the battery system. The steering system is powered electrically unlike most conventional vehicles which utilize a pump powered by the engine.


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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