Division 6 CALCULATION OF THE CO2 SAVINGS

To calculate the CO₂ savings of the innovative technology the following formula shall be used:

Formula 1:

$$C_{{\mathrm{CO}}_2}=\left[\left(B_{\mathrm{MC}}-E_{\mathrm{MC}}\right)-\left(B_{\mathrm{TA}}-E_{\mathrm{TA}}\right)\right]\times \mathrm{UF}$$

Where,

$C_{{\mathrm{CO}}_2}$

CO₂ savings [gCO₂/km];

B_MC

Arithmetic mean of the CO₂ emissions of the baseline technology vehicle under modified testing conditions [gCO₂/km];

E_MC

Arithmetic mean of the CO₂ emission of the eco-innovation technology vehicle under modified testing conditions [gCO₂/km];

B_TA

Arithmetic mean of the CO₂ emission of the baseline vehicle under type approval testing conditions [gCO₂/km];

E_TA

Arithmetic mean of the CO₂ emission of the eco-innovation technology vehicle under type approval testing conditions [gCO₂/km];

UF

Usage factor of the BMW engine idle coasting function is 0,62.

If it is demonstrated that the innovative technology is not active under the type approval testing conditions, the Formula 1 may be simplified as follows:

Formula 2:

$$C_{{\mathrm{CO}}_2}=\left(B_{\mathrm{MC}}-E_{\mathrm{MC}}\right)\times \mathrm{UF}$$

To determine B_MC, the same modified testing conditions shall be followed by a vehicle which does not have the BMW engine idle coasting function.

It shall be assumed that the baseline vehicle is able to perform a sailing curve (line 2' in Figure 2) without disconnecting the engine from the wheels, although with lower efficiency than a vehicle fitted with a BMW engine idle coasting function (i.e. able to disconnect the engine from the wheels).

Figure 2 illustrates that during the deceleration phases of the type approval (3) and the modified (2' + 3') testing conditions no fuel is used (cut-off) by the baseline vehicle.

In order to determine the CO₂ emissions of the baseline vehicle under the modified conditions (B_MC), those emissions shall be calculated based on the CO₂ emissions of the baseline vehicle determined under type approval hot start conditions using a conversion parameter (c-factor) which takes into account the effect of the modified testing conditions in accordance with the following Formula 3:

Formula 3:

$$c=\frac{B_{\mathrm{MC}}}{B_{{\mathrm{TA}}_{\mathrm{hot}}}}$$

As consequence, Formula 2 becomes:

Formula 4:

$$C_{{\mathrm{CO}}_2}=\left(c\times B_{{\mathrm{TA}}_{\mathrm{hot}}}-E_{\mathrm{MC}}\right)\times \mathrm{UF}$$

Where,

c

Conversion parameter which is 0,960;

$B_{{\mathrm{TA}}_{\mathrm{hot}}}$

Arithmetic mean of the CO₂ emission of the baseline vehicle under type approval hot start conditions [gCO₂/km];

E_MC

Arithmetic mean of the CO₂ emission of the eco-innovation vehicle under modified testing conditions [gCO₂/km];

UF

Usage factor of the coasting technology for the BMW technology which is 0,62; this value is representative only for the BMW fleet.