Diesel Vehicle (N1)

Note: for the diesel vehicle simulations (with both Phem and Cruise models) the coefficients of resistance to progress (F0 and F2) have been taken from Reg. 83.

Simulation tool: PHEM

Engine map: used emission map for average N1 Class III vehicle from PHEM.

Corrections: Increased air drag by 40% in order to match fuel consumption profile.

Results

Measured CO2 :192g/km (for cold start cycle)

Simulated CO2:188g/km (hot start conditions)

Relative Simulation results. Reference case (= 100%) case 2

Cycle type / Cycle WLTP / vehicle / length[km] / v[km/h] / fuel consumption / NOx / HC / CO / PM / PN / NO
Hot / Case 1 / Diesel / 18.1 / 31.5 / 93% / 73% / 107% / 148% / 83% / 80% / 73%
Hot / Case 2 / Diesel / 23.2 / 46.4 / 100% / 100% / 100% / 100% / 100% / 100% / 100%
Hot / Case 3 / Diesel / 23.0 / 46.0 / 99% / 98% / 99% / 101% / 95% / 97% / 98%

Diesel vehicle (N1)

Simulation tool: Cruise

Engine map: used emission map for average N1 Class III vehicle from PHEM.

Corrections: Increased air drag by 40% in order to match fuel consumption profile.

Results

Measured CO2 : 192g/km (for cold start cycle)

Simulated CO2: 178g/km (hot start conditions)

Relative Simulation results. Reference case (= 100%) case 2

Cycle type / Cycle WLTP / vehicle / length[km] / v[km/h] / fuel consumption
Hot / Case 1 / Diesel / 18.1 / 31.5 / 91.2%
Hot / Case 2 / Diesel / 23.2 / 46.4 / 100%
Hot / Case 3 / Diesel / 23.0 / 46.0 / 99.2%

Gasoline vehicle (M1)

Note: for the gasoline vehicle simulations (with both Phem and Cruise models) the coefficients of resistance to progress (F0 and F2) have been obtained from the vehicle manufacturer.

Simulation tool: PHEM

Engine map: used emission map for average N1 Class III vehicle from PHEM.

Corrections:.

Results

Measured CO2 : 120.7g/km (for cold start cycle)

Simulated CO2: 115g/km (hot start conditions)

Relative Simulation results. Reference case (= 100%) case 2

Cycle type / Cycle WLTP / gasolinevehicle / length [km] / v[km/h] / Fuel
[g/km] / Nox [g/km] / HC
[g/km] / CO
[g/km] / PM
[g/km] / PN
[#/km] / NO[
g/km]
Hot / Case 1 / M1 / 18.1 / 31.5 / 100% / 95% / 80% / 67% / 31% / 60% / 95%
Hot / Case 2 / M1 / 23.3 / 46.5 / 100% / 100% / 100% / 100% / 100% / 100% / 100%
Hot / Case 3 / M1 / 23.0 / 46.0 / 98% / 97% / 87% / 79% / 68% / 80% / 97%

Gasoline vehicle (M1)

Simulation tool: Cruise

Engine map:Generic Euro 5 Gasoline

Corrections: Increased losses in differential to match fuel consumption profile.

Results

Measured CO2 :120g/km (for cold start cycle)

Simulated CO2:115g/km (hot start conditions)

Relative Simulation results. Reference case (= 100%) case 2

Cycle type / Cycle WLTP / Gasoline vehicle / length[km] / v[km/h] / fuel consumption
Hot / Case 1 / M1 / 18.1 / 31.5 / 97.8%
Hot / Case 2 / M1 / 23.2 / 46.4 / 100%
Hot / Case 3 / M1 / 23.0 / 46.0 / 98.1%

From the above simulations one could think that a generic diesel vehicle is more sensitive than a gasoline vehicle to the 4th phase of the WLTC, whether it is an L3, or an Ex-H3 or an Ex-H2. In fact for the gasoline vehicle there seems to be a much lower difference among those 3 cases.

However it has been noted that the chassis dyno settings for the 2 series of simulations were not the same: F0 and F2 from Regulation 83 for the diesel vehicle; F0 and F2 from manufacturer for the gasoline vehicle.

In order to assess the impact of the chassis dyno setting on the CO2 emission predictions, a second round of simulations has been carried out for the gasoline vehicle with F0 and F2 taken from Regulation 83.

(F0 and F2 from Regulation 83. F0< than F0 manufacturer; F2> than F2 manufacturer)

Cycle type / Cycle WLTP / Gasoline vehicle / length[km] / v[km/h] / fuel consumption
Hot / Case 1 / M1 / 18.1 / 31.5 / 93.0%
Hot / Case 2 / M1 / 23.2 / 46.4 / 100%
Hot / Case 3 / M1 / 23.0 / 46.0 / 97.4%

As expected, the new setting has brought results more in line with those obtained with the diesel vehicle. The lower rolling resistance due to the use of the Reg. 83 parameters (F0) has implied lower CO2 emissions for Case 1 (where the 4th phase is L3), while the higher value of F2 coming from Reg. 83 compared to the manufacturer’s F2 has shown higher CO2 emissions for the Ex-H3 case.

A summary of all simulation results from Cruise model are shown in the following table.