The propulsion system shall be sized to provide sufficient power to enable the bus to meet the defined acceleration, top speed, and gradability requirements, and operate all propulsion-driven accessories for use in all 50 states and Canada using actual road test results or computerized vehicle performance data.
6.1Top speed
The bus shall be capable of achieving a top speed of 65 mph (100 kph) on a straight, level road at GVWR with all accessories operating. The bus shall be capable of safely maintaining the vehicle speed according to the recommendations by the tire manufacturer.
Note: Values are assumed to be sustained. Manufacturer shall supply Agency with data if there is a variance between peak performance and sustained vehicle performance.
6.2Gradability
Gradability requirements shall be met on grades with a dry commercial asphalt or concrete pavement at GVWR with all accessories operating.
Default
The propulsion system and drivetrain shall enable the bus to achieve and maintain a speed of 40 mph (65 kph) on a 2½ percent ascending grade and 15 mph (24 kph) on a 10 percent ascending grade continuous.
Alternative
[Agency will provide operating profile information to the contractor.]
Note: Values are assumed to be sustained. Manufacturer shall supply Agency with data if there is a variance between peak performance and sustained vehicle performance.
6.3Acceleration
The acceleration shall meet the requirements below and shall be sufficiently gradual and smooth to prevent throwing standing passengers off-balance. Acceleration measurement shall commence when the accelerator is depressed.
MAXIMUM IDLE START ACCELERATION TIMES ON A LEVEL SURFACE1
Table 1
Speed
|
Maximum time
(seconds)
|
mph
|
kph
|
10
|
16
|
5
|
20
|
32
|
10
|
30
|
48
|
18
|
40
|
64
|
30
|
50
|
80
|
60
|
Top speed
|
Top speed
|
|
1. Vehicle weight = GVWR
| Hybrid
The propulsion and braking systems shall meet the performance requirements of the Duty Cycle.
Braking application and performance shall remain consistent regardless of hybrid system State of Charge (SOC) or other variances related to regenerative braking.
Default
The system shall be programmable to allow optimization of acceleration and deceleration rate. Performance may be affected. Manufacture shall supply performance data.
IP 7.Operating range
The operating range of the coach when run on the design operating profile as stated in the “Design Operating Profile.”
7.1Diesel
The operating range of the coach when run on the Transit Coach Operating Duty Cycle (ADB) cycle shall be at least 350 mi (560 km) or 20 hrs with full fuel capacity.
7.2CNG
The operating range of the coach when run on the ADB cycle shall be at least 350 mi (560 km) or 20 hrs with an initial gas settled pressure of 3,600 psi (US) or 3,000 psi (Canada) at 70°F (21°C).
7.3Hybrid
The operating range of the coach when run on the design operating profile “Design Operating Profile” shall be at least 350 miles (km) on a full tank of fuel.
IP 8.Fuel economy
Test results from the Altoona fuel economy tests or other applicable test procedures shall be provided to the Agency. Results shall include vehicle configuration and test environment information.
Fuel economy data shall be provided for each design operating profile.
Fuel economy tests shall be run on these four duty cycles and average speeds:
-
Manhattan, 6.8 mph
-
Orange County, 12.7 mph
-
Urban Dynamometer Driving Schedule (UDDS), 19 mph
-
idle time
The procuring agency will provide a percentage of each duty cycle that is representative of the agency’s service.
Test results from the Altoona fuel economy tests or other applicable test procedures shall be provided to the Procuring Agency. Results shall include vehicle configuration and test environment information.
8.1Hybrid
Energy storage system state of charge correction methods stated in SAE J2711 shall be utilized.
POWER PLANT
IP 9.Engine
The engine shall comply with applicable local, state, provincial and/or federal emissions and useful life requirements. Components of the fuel management and/or control system shall have a design life of not less than 150,000 miles without replacement or major service. The lifetime estimate is based on the design operating profile.
The engine shall be equipped with an electronically controlled management system, compatible with either 12- or 24-volt power distribution. The engine control system shall be capable of transmitting and receiving electronic inputs and data from other drivetrain components and broadcasting that data to other vehicle systems. Communication between electronic drivetrain components and other vehicle systems shall be made using the communications networks. The engine’s electronic management system shall monitor operating conditions and provide instantaneous adjustments to optimize both engine and bus performance. The system shall be programmable to allow optimization of programmable features.
The engine starting system shall be protected by an interlock that prevents its engagement when the engine is running. Special equipment or procedures may be employed to start the bus when exposed to temperatures less than 30 °F for a minimum of four hours without the engine in operation. All cold weather starting aids, engine heating devices and procedures shall be of the type recommended by the engine manufacturer and approved by the procuring agency. The integration of all systems on the vehicle relative to engine idle speed shall be the responsibility of the vehicle manufacturer to meet the requirements of the transit property.
The engine control system shall protect the engine against progressive damage. The system shall monitor conditions critical for safe operation and automatically derate power and/or speed and initiate engine shutdown as needed.
Default
Automatic engine protection/shutdown override feature
A control shall be available to the operator/driver that when constantly depressed and released will delay the engine shutdown or allow the bus to be moved. Override action shall be recorded. This data shall be retrievable by the procuring agency.
Alternative
No requirement for an automatic engine protection/shutdown override feature
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