Division 7 Calculation of the accountable share of the mechanical power saving

The high efficient alternator leads to the saved mechanical power which is to be calculated in two steps. In the first step the saved mechanical power is to be calculated under ‘real world’ conditions. The second step is to calculate the saved mechanical power under type approval conditions. Subtracting these 2 mechanical power savings is to result in the accountable share of the saved mechanical power.

The saved mechanical power under ‘real world’ conditions is to be calculated with formula (6).

Formula (6)

$${\mathrm{\Delta {\rm P}}}_{m-\mathrm{RW}}=\left(P_{\mathrm{RW}}∕{\eta }_{{\rm A}}\right)-\left(P_{\mathrm{RW}}∕{\eta }_{{\rm A}-\mathrm{EI}}\right)$$

Where:

ΔΡ_m–RW

Saved mechanical power under real world conditions (W);

P_RW

Electric power under real world conditions, which is 750 W;

η_Α

Efficiency of the baseline alternator;

η_Α–EI

Efficiency of the high efficient alternator

The saved mechanical power under type-approval conditions is to be calculated with formula (7).

Formula (7)

$${\mathrm{\Delta {\rm P}}}_{m-\mathrm{TA}}=\left(P_{\mathrm{TA}}∕{\eta }_{{\rm A}}\right)-\left(P_{\mathrm{TA}}∕{\eta }_{{\rm A}-\mathrm{EI}}\right)$$

Where:

ΔΡ_m–TA

Saved mechanical power under type approval conditions (W);

P_TA

Electric power under type approval conditions, which is 350 W;

η_Α

Efficiency of the baseline alternator;

η_Α–EI

Efficiency of the high efficient alternator

The accountable share of saved mechanical power is calculated with formula (8).

Formula (8)

$${\mathrm{\Delta {\rm P}}}_m={\mathrm{\Delta {\rm P}}}_{m-\mathrm{RW}}-{\mathrm{\Delta {\rm P}}}_{m-\mathrm{TA}}$$

Where:

ΔΡ_m

Accountable share of saved mechanical power (W);

ΔΡ_m–RW

Saved mechanical power under real world conditions (W);

ΔΡ_m–TA

Saved mechanical power under type approval conditions (W);