Division 3.1

United Kingdom

Option 1: Measurement of the torque independent losses, calculation of the torque dependent losses.

The torque loss T_l ,_in on the input shaft of the transmission shall be calculated by

T_l,in (n_in , T_in , gear) = T_{l,in,min_loss} + f_T * T_in + f_{loss_corr} * T_in + T_{l,in,min_el} + f_{el_corr} * T_in

The correction factor for the torque dependent hydraulic torque losses shall be calculated by

f_{loss_corr} = \frac{(T_{l,in,max_loss} - T_{l,in,min_loss})}{T_{max,in}}

The correction factor for the torque dependent electric torque losses shall be calculated by

f_{el_corr} = \frac{(T_{l,in,max_el} - T_{l,in,min_el})}{T_{max,in}}

The torque loss at the input shaft of the transmission caused by the power consumption of transmission electric auxiliary shall be calculated by

T_{l,in,el} = \frac{P_{el}}{(0,7 \times n_{in} \times \frac{2 π}{60})}

where:

T_l,in

Torque loss related to input shaft [Nm]

T_{l,in,min_loss}

Torque independent loss at minimum hydraulic loss level (minimum main pressure, cooling/lubrication flows etc.), measured with free rotating output shaft from testing without load [Nm]

T_{l,in,max_loss}

Torque independent loss at maximum hydraulic loss level (maximum main pressure, cooling/lubrication flows etc.), measured with free rotating output shaft from testing without load [Nm]

f_{loss_corr}

Loss correction for hydraulic loss level depending on input torque [-]

n_in

Speed at the transmission input shaft (downstream of torque converter, if applicable) [rpm]

f_T

Torque loss coefficient = 1 – η_T

T_in

Torque at the input shaft [Nm]

η_T

Torque dependent efficiency (to be calculated); for a direct gear f_T = 0,007 (η_T = 0,993) [-]

f_{el_corr}

Loss correction for electric power loss level depending on input torque [-]

T_{l,in, el}

Additional torque loss on input shaft by electric consumers [Nm]

T_{l,in,min_el}

Additional torque loss on input shaft by electric consumers corresponding to minimum electric power [Nm]

T_{l,in,max_el}

Additional torque loss on input shaft by electric consumers corresponding to maximum electric power [Nm]

P_el

Electric power consumption of electric consumers in transmission measured during transmission loss testing [W]

T_max,in

Maximum allowed input torque for any forward gear in the transmission [Nm]