The Insight meets the California ULEV standards. Its catalytic converter is specially designed and actually attracts NOx molecules during lean-burn conditions. It catalyzes the NOx molecules to water, CO2 and N2. All the torque used to move the vehicle comes from the electric motor and not the IC engine. The benefit with this type of hybrid system is that the IC engine drives the generator to run at optimum performance.
Buses use a series hybrid where a combustion engine is coupled directly to a generator.
The generator then produces electric energy to operate the traction motor. This configuration allows the IC engine to run at optimum revolutions per minute , reducing energy consumption and emissions. Braking energy is recovered and no energy is wasted during standstill and idling. In a parallel hybrid system, there is a direct mechanical connection between the IC engine and the wheels, as in a conventional vehicle. There is also a direct connection between the electric motor and the wheels.