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HybriDrive® propulsion (Hybrid-electric propulsion systems)

Our successful hybrid electric drive system is a series configuration, designed specifically for fuel savings and its pathway to electrification. HybriDrive propulsion systems provide propulsion for 35’-40’ buses, articulated, and double deck buses.

The series design is optimized for city bus duty cycles that typically have low average speeds and frequent stops. In this type of environment, series design provides better bus fuel economy and emission reductions than a parallel solution. Our latest product, HybriDrive Series-E, not only provides electric propulsion, but can power all bus accessories electrically while providing zero emission modes and a path to an all-electric vehicle.

HybriDrive propulsion provides three different systems based on vehicle weight, the HDS100, HDS200, and HDS300 system. The HDS300 is available to power North American articulated bus platforms. The system exceeds APTA guidelines for sustainability, and it is capable of powering vehicles up to 63,000 pounds while providing superior acceleration, making it easy to climb steep hills, and sustain a top speed of 65mph.

Click on component name for more information:

The Modular Traction System (MTS) is available in three different sizes dependent upon power demand: HDS100, HDS200 and HDS300. The system is comprised of a motor and a generator. The generator supplies power to the electric drive motor and electric accessories. The electric motor powers the bus by turning the wheels, providing a smooth acceleration. When the bus slows, the motor acts like a generator to recapture energy for later use.

The Energy Storage System (ESS) uses a long-life lithium battery to provide power during acceleration and store power during regenerative braking, making the bus more fuel efficient.

The Propulsion Control Systems (PCS) directs the power flow to the right place at the right time for increased efficiency.

The optional HybriDrive Cooling Package (HCP) provides integrated, self-contained thermal management for the entire hybrid system and particularly supports the efficient use of Accessory Power Systems (APS1, APS2 or APS3).

Accessory Power System - APS1 provides power for accessory loads dependent on your needs. APS1 functions as an electronic alternator to power conventional 28 Vdc electric loads, such as cooling fans and pumps, plus all hybrid cooling systems.

APS2 supports full electrification of vehicle accessories. This unit provides all the benefits of APS1 while also supplying enough variable frequency 230 Vac power for the electrification of larger accessory loads such as air compressors, power steering, and air conditioning. APS2 also enables electric vehicle modes such as stop/start mode.

APS3 supports full electrification of vehicle accessories like APS2, but APS3 has an additional and completely independent variable frequency 230 Vac supply, providing the ability to power two accessories or two groups of accessories independently from each other. This can improve efficiency so each accessory is operating at its optimal speed for the demand and permits continued operation of one accessory should the other experience a fault. The APS3 can also serve as a power distribution unit, potentially eliminating the need for an additional OEM-installed PDU.

City bus & articulated bus diagram and rendering
35'-40' and articulated bus
Double decker bus diagram and rendering
Double decker bus