Honda e:HEV Hybrid System – How it Works (Ko Yamamoto, Technical Advisor Honda Motor Europe)

Powerful e:HEV hybrid technology delivers a compelling blend of performance and efficiency

New Jazz is the first model to be presented under Honda's new e:TECHNOLOGY branding.
Newly-developed hybrid technology features two compact motors combined with a 1.5-litre DOHC i-VTEC petrol engine.
Maximum power output of 109 PS / 80kW and 253 Nm of electric propulsion torque.

For the first time, the Jazz will be sold exclusively across Europe with an advanced hybrid powertrain. Carrying Honda's new e:HEV badge, the all-new Jazz has been engineered to deliver an exceptional blend of strong performance and impressive efficiency, to complement its class-leading levels of interior comfort and ultimate usability.

The e:HEV system is newly developed for Jazz and engineered to deliver an enjoyable driving experience. It consists of two compact, powerful electric motors connected to a 1.5-litre DOHC i-VTEC petrol engine, a lithium-ion battery and an innovative fixed-gear transmission via an intelligent power control unit, which all work harmoniously together to provide a smooth and direct response.

The total output of 109 PS / 80kW can propel the car to 100km/h in 9.4 seconds and on to a maximum speed of 175 km/h. The effect is an effortless and comfortable journey, whether travelling through urban areas or cruising at high speed on motorways. Its fuel-efficient hybrid system produces CO2 emissions from 102 g/km (WLTP) and fuel economy of 4.5l/100km (WLTP) on the standard model and 110 g/km (WLTP) and 4.8l/100km (WLTP) on the Crosstar.

To deliver such a highly-rewarding driving experience and exceptional efficiency, the advanced e:HEV hybrid set-up seamlessly selects from three interchangeable drive modes:

EV Drive: the lithium-ion battery supplies power to the electric propulsion motor directly.
Hybrid Drive: the engine supplies power to the electric generator motor, which in turn supplies it to the electric propulsion motor.
Engine Drive: the petrol engine is connected directly to the wheels via a lock-up clutch and driveforce is transmitted directly from engine to the wheels.

In most urban driving situations, optimum efficiency is achieved through seamless transitions between EV Drive and Hybrid Drive. For driving at highway speeds, Engine Drive is used, supplemented by an on-demand peak power ‘boost’ from the electric propulsion motor for fast acceleration.

In Hybrid Drive, excess power from the petrol engine can also be diverted to recharge the battery via the generator motor. EV Drive is also engaged when the car is decelerating, harvesting energy through regenerative braking to recharge the battery.

Switching between the three driving modes is unnoticeable to occupants; Jazz engineers dedicated significant efforts to minimising lag during transitions. The high-speed electric motors have been developed in-house by Honda to be as lightweight, compact and efficient as possible, the electric propulsion motor spins up to 13,300 rpm to achieve a maximum speed of 175 km/h. The maximum torque is generated at 0 rpm for substantial low-speed acceleration.

Rather than using a conventional transmission, Jazz is equipped with a newly-developed Electronically Controlled Continuously Variable Transmission (e-CVT) with a single fixed-gear ratio to create a direct connection between moving components. The result is a smooth and reassuring transfer of torque with a linear feel during acceleration across all drive modes.

When in Hybrid Drive mode the all-new e-CVT control logic ensures that the electric propulsion motor provides powerful torque, whilst the engine provides a direct and linear feel during acceleration, similar to that of a multi-stage transmission. When more power is required, the new control logic can constantly select the ideal engine speed. This has the impact of maintaining a relationship between vehicle speed and engine speed and a more linear feeling, experienced by the driver and passengers as acceleration sound. This optimised torque output, with more responsive and consistent delivery, is a key component of the fun-to-drive character of Jazz.

As well as being more refined, the e-CVT developed for Jazz is more compact than the conventional planetary e-CVT units typically found in hybrid vehicles from other marques. With a focus on dimensions and clever integration, the new e-CVT is an example of the intelligent packaging evident elsewhere on Jazz.

Jazz is the first model in Honda's European line-up to wear the new e:HEV branding that will appear on all future Honda full hybrid vehicles.