Method for determining a transmission ratio for an automatic transmission arranged in a drive train of a motor vehicle

• US 6,640,177 B2
• Filed: 01/02/2001
• Issued: 10/28/2003
• Est. Priority Date: 12/30/1999
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Frei, Rasmus, Poljansek, Marko
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US09/750,685
• Publication Number:
  US 20010007964A1
• Time in Patent Office: 1,029 Days
• Field of Search: 701/51, 701/52, 192/31, 477/46, 477/68, 477/174
• US Class Current: 701/51
• CPC Class Codes: F16H 2059/142 of driving resistance calculated from weight, slope, or the like
• CPC Class Codes: F16H 2059/366 Engine or motor speed
• CPC Class Codes: F16H 2059/385 Turbine speed
• CPC Class Codes: F16H 2061/0096 using a parameter map
• CPC Class Codes: F16H 59/14 Inputs being a function of torque or torque demand
• CPC Class Codes: F16H 59/24 dependent on the throttle opening
• CPC Class Codes: F16H 59/48 Inputs being a function of acceleration
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals

Abstract

The invention relates to a method for determining a transmission ratio for an automatic transmission arranged in the drive train of a motor vehicle. Operating parameters of the vehicle and especially of equipment arranged in the drive train are made available in a control apparatus to determine the transmission ratio. The invention provides that the transmission ratio (i) of the transmission is determined in dependence upon an instantaneous vehicle load.

Claims

1. A method of determining a transmission ratio (i) for an automatic transmission mounted in the drive train of a motor vehicle, the method comprising the steps of:

providing a control apparatus wherein operating parameters of the motor vehicle are made available to determine the transmission ratio (i);

determining the transmission ratio (i) of said automatic transmission in dependence upon an instantaneous load of said motor vehicle with said instantaneous load of said motor vehicle being included in a characteristic line (KL_DKI) for a throttle flap position (DKI); and

,

determining the characteristic line (KL_DKI, KL_DKI,c) in dependence upon an acceleration (a) of said motor vehicle with said acceleration (a) being an index for the instantaneous load of said motor vehicle.

2. The method of claim 1, wherein:

equipment including said automatic transmission are mounted in said drive train; and

, operating parameters of said equipment are made available in said control apparatus to determine said transmission ratio (i).

3. A method of determining a transmission ratio (i) for an automatic transmission mounted as part of equipment in the drive train of a motor vehicle, the method comprising the steps of:

providing a control apparatus wherein operating parameters of the motor vehicle are made available to determine the transmission ratio (i);

making operating parameters of said equipment available in said control apparatus to determine said transmission ratio (i);

determining the transmission ratio (i) of said automatic transmission in dependence upon an instantaneous load of said motor vehicle with said instantaneous load of said vehicle being included in a characteristic line (KL_DKI) for a throttle flap position (DKI); and

,

determining a corrected characteristic line (KL_DKI,c) for determining said transmission ratio (i) utilizing the computation rule;

${\mathrm{KL}}_{\mathrm{DKI},c}=\frac{{\mathrm{KL}}_{\mathrm{DKI}}·<br><br>\left(\left(S+R\right)·<br><br>{\mathrm{DKI}}_{\max }-S·<br><br>\mathrm{DKI}\right)}{{\mathrm{DKI}}_{\max }}$

 

wherein;

S is a spread;

R is a residual factor; and

,

DKI_max is a maximum throttle flap position.

4. The method of claim 3, comprising the further step of determining the characteristic line (KL_DKI, KL_DKI,c) in dependence upon an acceleration (a) of said motor vehicle with said acceleration (a) being an index for the instantaneous load of said motor vehicle.

5. The method of claim 4, wherein said acceleration (a) is included in the form of a difference acceleration (a_diff) which is computed in accordance with the computation rule:

$a_{\mathrm{diff}}=a_{\exp ,c}-a_{\mathrm{act}}$

wherein;

a_exp,c is a corrected expected acceleration; and

,

a_act is an actual acceleration.

6. The method of claim 5, wherein said expected acceleration (a_exp) is included in the form of a normalized acceleration (a_norm) which is computed in accordance with the computation rule:

$a_{\mathrm{norm}}=\frac{a_{\mathrm{mean}}}{a_{\max }}$

wherein;

a_mean is a mean value of the expected acceleration (a_exp); and

,

a_max is the difference acceleration (a_diff) under maximum load.

7. The method of claim 6, wherein the expected acceleration (a_exp) results from the computation rule:

$a_{\exp }=\frac{M_{\mathrm{res}}}{m_{\mathrm{veh}}·<br><br>r_{\mathrm{dyn}}}-a_{\mathrm{tran}}$

wherein;

M_res is a reserve torque;

m_veh is the mass of said motor vehicle;

r_dyn is a dynamic wheel radius; and

,

a_tran is a transverse acceleration.

8. The method of claim 7, wherein the reserve torque (M_res) is determined from the relationship:

$M_{\mathrm{res}}=M_{\mathrm{wheel}}-M_{\mathrm{fw}}$

wherein;

M_wheel is a resulting wheel torque; and

,

M_fw is the total running resistance torque.

9. The method of claim 8, wherein the total running resistance torque (M_fw) is determined in dependence upon a vehicle speed (v_veh) from a characteristic line (KL_fw) which, in turn, is determined in an unloaded vehicle in a plane.

10. The method of claim 9, wherein the resulting wheel torque (M_wheel) is determined from the relationship:

$M_{\mathrm{wheel}}=M_{\mathrm{ab}}·<br><br>i_{\mathrm{hi}}-M_{\mathrm{wheel},\mathrm{rot}}$

wherein;

M_ab is the output torque;

i_hi is a rear axle transmission ratio; and

,

M_wheel,rot is a wheel rotation torque.

11. The method of claim 9, wherein the wheel rotation torque (M_wheel,rot) is determined from the relationship:

$M_{\mathrm{wheel},\mathrm{rot}}=\frac{<br><br>n_{\mathrm{wheel}}}{<br><br>t}·<br><br>J_{\mathrm{wheel}}·<br><br>r·<br><br>2<br><br>\mathrm{\pi <br><br>}$

wherein;

dn_wheel/dt is a gradient of a wheel rpm (n_wheel);

J_wheel is a mass moment of inertia of the wheels; and

,

r is a number of wheels.

12. The method of claim 11, wherein the output torque (M_ab) is determined from the relationship:

$M_{\mathrm{ab}}=M_{\mathrm{tur}}·<br><br>i$

wherein;

M_tur is a turbine torque; and

,

i is the actual transmission ratio.

13. The method of claim 12, wherein the turbine torque (M_tur) is determined from the relationship:

$M_{\mathrm{tur}}=\mathrm{WV}·<br><br>\left(M_{\mathrm{mot}}-M_{\mathrm{mot},\mathrm{rot}}\right)$

wherein;

WV is a converter amplification;

M_mot is a motor torque; and

,

M_mot,rot is a motor rotation torque.

14. The method of claim 13, wherein the converter amplification (WV) is determined from the relationship:

$\mathrm{WV}=\frac{n_{\mathrm{mot}}}{n_{\mathrm{tur}}}$

wherein;

n_mot is a motor rpm; and

,

n_tur is a turbine rpm.

15. The method of claim 14, wherein the motor rotation torque (M_mot,rot) is determined from the relationship:

$M_{\mathrm{mot},\mathrm{rot}}=\frac{<br><br>n_{\mathrm{mot}}}{<br><br>t}·<br><br>\left(J_{\mathrm{mot}}+J_{\mathrm{tur}}\right)·<br><br>2<br><br>\mathrm{\pi <br><br>}$

wherein;

dn_mot/dt is a gradient of the motor rpm;

J_mot is a mass moment of inertia of the motor; and

,

J_tur is a mass moment of inertia of the turbine.

16. The method of claim 3, comprising the further step of determining the characteristic line (KL_DKI, KL_DKI,c) in dependence upon an acceleration (a) of said motor vehicle with said acceleration (a) being an index for the instantaneous load of said motor vehicle.

17. The method of claim 16, wherein said acceleration (a) is included in the form of a difference acceleration (a_diff) which is computed in accordance with the computation rule:

$a_{\mathrm{diff}}=a_{\exp ,c}-a_{\mathrm{act}}$

wherein;

a_exp,c is a corrected expected acceleration; and

,

a_act is an actual acceleration.

18. The method of claim 17, wherein said expected acceleration (a_exp) is included in the form of a normalized acceleration (a_norm) which is computed in accordance with the computation rule:

$a_{\mathrm{norm}}=\frac{a_{\mathrm{mean}}}{a_{\max }}$

wherein;

a_mean is a mean value of the expected acceleration (a_exp); and

,

a_max is the difference acceleration (a_diff) under maximum load.

19. The method of claim 18, wherein the expected acceleration (a_exp) results from the computation rule:

$a_{\exp }=\frac{M_{\mathrm{res}}}{m_{\mathrm{veh}}·<br><br>r_{\mathrm{dyn}}}-a_{\mathrm{tran}}$

wherein;

M_res is a reserve torque;

m_veh is the mass of said motor vehicle;

r_dyn is a dynamic wheel radius; and

,

a_tran is a transverse acceleration.