Appendix 9

United Kingdom

Generic model – torque converter

Generic torque converter model based on standard technology:

For the determination of the torque converter characteristics a generic torque converter model depending on specific engine characteristics may be applied.

The generic TC model is based on the following characteristic engine data:

n_rated

Maximum engine speed at maximum power (determined from the engine full-load curve as calculated by the engine pre-processing tool) [rpm]

T_max

Maximum engine torque (determined from the engine full-load curve as calculated by the engine pre-processing tool) [Nm]

Thereby the generic TC characteristics are valid only for a combination of the TC with an engine sharing the same specific characteristic engine data.

Description of the four-point model for the torque capacity of the TC:

Generic torque capacity and generic torque ratio:

where:

T_P1000

Pump reference torque; $T_{P 1000} = T_{P} \times {(\frac{1000 rpm}{n_{p}})}^{2}$ [Nm]

Speed ratio; $v = \frac{n_{2}}{n_{1}}$ [-]

Torque ratio; $μ = \frac{T_{2}}{T_{1}}$ [-]

v_s

Speed ratio at overrun point; $v_{s} = \frac{n_{2}}{n_{1}}$ [-]

For TC with rotating housing (Trilock-Type) v_s typically is 1. For other TC concepts, especially power split concepts, v_s may have values different from 1.

v_c

Speed ratio at coupling point; $v_{c} = \frac{n_{2}}{n_{1}}$ [-]

v₀

Stall point; v₀ = 0 [rpm]

v_m

Intermediate speed ratio; $v_{m} = \frac{n_{2}}{n_{1}}$ [-]

The model requires the following definitions for the calculation of the generic torque capacity:

Stall point:
- Stall point at 70 % nominal engine speed.
- Engine torque in stall point at 80 % maximum engine torque.
- Engine/Pump reference torque in stall point:
  $T_{P 1000} (v_{0}) = T_{\max} \times 0,80 \times {(\frac{1000 rpm}{0,70 \times n_{n}})}^{2}$
Intermediate point:
- Intermediate speed ratio v_m = 0,6 * v_s
- Engine/pump reference torque in intermediate point at 80 % of reference torque in stall point:
  $T_{P 1000} (v_{m}) = 0,8 \times T_{P 1000} (v_{0})$
Coupling point:
- Coupling point at 90 % overrun conditions: v_c = 0,90 * v_s
- Engine/pump reference torque in clutch point at 50 % of reference torque in stall point:
  $T_{P 1000} (v_{c}) = 0,5 \times T_{P 1000} (v_{0})$
Overrun point:
- Reference torque at overrun conditions = v_s :
  $T_{P 1000} (v_{s}) = 0$

The model requires the following definitions for the calculation of the generic torque ratio:

Stall point:
- Torque ratio at stall point v₀ = v_s = 0:
  $μ (v_{0}) = \frac{1,8}{v_{s}}$
Intermediate point:
- Linear interpolation between stall point and coupling point
Coupling point:
- Torque ratio at coupling point v_c = 0,9 * v_s :
  $μ (v_{c}) = \frac{0,95}{v_{s}}$
Overrun point:
- Torque ratio at overrun conditions = v_s :
  $μ (v_{s}) = \frac{0,95}{v_{s}}$
Efficiency:
n = μ * v

Linear interpolation between the calculated specific points shall be used.