Document ID: chunk:federal_register_of_legislation:F2009C00402:body:0:p27
Version: federal_register_of_legislation:F2009C00402
Segment Type: other
Provision Reference: 
Character Range: 75257–78285

for DPFs may swing the cost benefit balance towards DOCs in the future.

 PFTs do not have the exhaust temperature restriction and will not block up if the duty cycle requirements are not achieved. With PFTs, there is a reduced need to data log the exhaust temperatures and backpressures (see below).

 Assessment of candidate vehicles: Due to the importance of duty cycle and exhaust temperature, it can be useful to log exhaust temperatures of candidate retrofit vehicles, before deciding on a suitable aftertreatment device.

 Data loggers can be fitted to candidate vehicles to record and store exhaust temperature data over a period to establish the exhaust temperature profile for a vehicle's typical duty cycle. A DPF, for example, could be fitted to a truck engine with exhaust temperatures that exceed 260° C for 40 percent of the time, or to similar trucks working similar duty cycles. A DOC fitted to this vehicle would always reduce PM to some extent but less than that achieved by a DPF.

 It has been established that there is a relationship between exhaust temperature and PM emissions. As exhaust temperature rises, PM emissions rise. As a result, exhaust temperature can potentially be used to estimate likely percentage PM emission reductions from installation of a DOC or DPF. The average reduction in PM emissions for a particular vehicle on a particular duty cycle can be calculated by using the DOC/DPF temperature/efficiency curve.

3.3   Program Evaluation

 The evaluation of a retrofit program serves two main purposes:

 1. To support the vehicle selection process in section 3.1 for a proposed program.

 2. To provide a means of assessing and reviewing the effectiveness of a program in operation.

3.3.1   To Support Target Vehicle Selection

 As indicated in section 3.1, one of the criteria in selecting target vehicles is the cost effectiveness of any proposed program for the target group.  Determining the cost effectiveness of particular approaches enables the objective comparison of different measures and the consideration of the need for further incentives.

 One basic formula for such an estimation is as follows:

Cost Effectiveness ($/kg Emissions) = (Cost) / (Emission Reduction)

 Where:
Cost($)                =  (no. vehicles fitted)*(DOC/DPF/PFT unit cost)/
                          (DOC/DPF/PFT unit life years)
Emission Reduction     =  (emissions,fleet,year)*(DOC/DPF/PFT emission reduction factor)
Emission,fleet,year    =  (emission, vehicle, year)* (fleet size)* (fleet suitability)* (fleet penetration)
Emission,vehicle,year  =  (emission rate)*(annual vehicle kilometres travelled)

Notes:

"Fleet suitability"

Refers to the estimate of the proportion of the fleet that will actually be suitable for retrofit. For example, it may be determined that 15% of a particular fleet is too old to warrant the cost of retrofit, or conversely 10% of the fleet meets ADR80/00  (Euro 3) and would not benefit significantly from retrofit.

"Fleet penetration"

Refers