Proven Reliability, Durability And Performance
Allison Hybrids have proven to be the most dependable and efficient hybrid systems at work anywhere in the world. The Allison Hybrid EP system features a two-mode split parallel architecture with a pure mechanical path and a pure electrical path to achieve the highest energy efficiency. Which makes it perfectly suited for in-city stop-and-go transit as well as long distance highway applications.
Hybrid Bus Ratings
Allison H 40 EP Drive Unit - Transit Bus
280 hp (209 kW)
Rated Input Torque:
910 lb-ft (1234 N•m)
Rated Input Speed:
Allison H 50 EP Drive Unit - Suburban Coach / Articulated Bus
330 hp (246 kW)
Rated Input Torque:
1050 lb-ft (1424 N•m)
Rated Input Speed:
The Pinellas Suncoast Transit Authority (PSTA) provides public transportation services to around 40,000 riders a day in Pinellas County, Florida, which includes the St. Petersburg, Clearwater and nearby beaches on the Gulf of Mexico. According to Brad Miller, CEO of PSTA, "Our fuel budget of more than $6 million a year, outside of our labor costs, is our number one greatest expense." So, having Allison Hybrid buses that deliver greatly improved fuel economy, compared to their conventional diesel buses, is a huge benefit.
More Information on the Allison Hybrid Bus
H 40 EP / H 50 EP Drive Unit
Same proven form, fit and function.
- Two-mode parallel hybrid operates automatically as a parallel hybrid or series hybrid
- Continuously variable drive with an infinite number of ratios
- Automatically adjusts ratios to operate at optimum power curves to attain best performance and fuel economy
ESS2 (Energy Storage System)
The latest Nickel Metal Hydride battery cell technology from PEVE is utilized in this second-generation unit.
- Common, high-capacity hardware to handle every bus size
- First generation ESS achieved over 100 million miles of revenue service without any end-of-life battery cell failures
- New technology proven durable and reliable to avoid risks associated with experimental energy storage devices
Fourth Generation Electronic Controls
The latest commercial high-volume, high-quality controller features common hardware to all the latest Allison transmissions and hybrids.
- Greater processing power and memory capability
- Memory expansion allows for further technology evolution
- Fewer electrical connections for greater system durability and reliability
- Full optimization with latest engines
- Allison HyValue™ performance features HyGain™, HyIdle™ and HyTraction™
DPIM2 (Dual Power Inverter Module)
The second-generation unit features more robust internal hardware with enhanced redundancy for greater reliability. Externally, this unit is fully interchangeable with all prior production units.
Fuel and Emissions Reduced
When operating with 2010 EPA diesel engines, the Allison Hybrid EP system dramatically reduces both diesel fuel consumption and CO2 emissions. Typical fuel economy improves 20-30% over similar vintage standard diesel buses. (Results can vary depending on the duty-cycles.)
Regenerative Braking and Savings
When decelerating or stopping, the system converts the vehicle's kinetic energy to stored electric energy. In effect, the motor becomes a generator. Forty percent of the energy to accelerate the bus comes from the braking energy saved.
Regenerative braking also saves on brake maintenance costs. Some properties are experiencing brake life of 170,000 miles with Allison Hybrids as compared to 55,000 miles with a standard bus.
Fast, Smooth Acceleration
A bus equipped with the Allison Hybrid EP system significantly out-accelerates a similar bus equipped with a conventional drivetrain or an alternative fuel system. The acceleration is smooth and seamless. Drivers and passengers prefer Allison Hybrid to standard buses because the ride is smooth and comfortable.
With Allison's HyGain™ feature, a transit property can adjust the acceleration rate to fit their operating requirements. Adjusting HyGain downward further increases fuel economy.
The Allison Hybrid EP system helps reduce noise pollution compared to conventional buses. At 79 db @ 10 meters, buses equipped with the system approach the sound level of passenger cars.
Easy Installation, Easy Maintenance
2011 Allison Hybrid EP system components fit in virtually the same space claim as a conventional drivetrain. This compact package easily installs in T-drive driveline layout. The drive unit was designed to resemble an Allison Bus Series transmission so maintenance training and repairs are easier. The H40 EP and H 50 EP share common parts to minimize fleet inventory.
Allison has taken the next major technology step with the introduction of DC-to-DC converter capabilities. A solid-state DC-to-DC converter eliminates traditional alternator to provide greater reliability while lowering operational costs and maintenance issues. The converter will not use the ESS2 for any stored energy, thereby maintaining our unequalled hybrid battery life.
DC-DC converters have the nickname of "beltless alternator" since they are electrically driven solid-state devices that maintain electrical efficiencies of 91-95%. Having such a high electrical efficiency, these converters replace large belt-driven alternators. They do not require any type of mechanical belt drive system and associated maintenance requirements.
The converter powers not only traditional 12/24-volt busloads, but also accommodates the electric radiator; charge-air-cooling and hybrid drive electric fans. This not only provides better efficiency, it eliminates hydraulic fan drives.
Our extensive network of over 1,550 authorized Allison Distributors and Dealers worldwide, means convenient, factory-quality Allison service is always close at hand.