Drive control system for achieving target driveshaft power in a motor vehicle

• US 6,684,145 B1
• Filed: 04/11/2002
• Issued: 01/27/2004
• Est. Priority Date: 07/05/1999
• Status: Expired due to Term

• Current Assignee: C.R.F. Societa Consortile Per Azioni
• Original Assignee: C.R.F. Societa Consortile Per Azioni
• Inventors: Lupo, Massimo, Re Fiorentin, Stefano, Gianoglio, Renato, Ellena, Giovanni, Porta, Attilio
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US10/030,044
• Time in Patent Office: 656 Days
• Field of Search: 701/54, 701/51, 701/53, 701/69, 701/79, 701/93, 701/96, 477/84, 477/91, 477/110, 280/12.14, 123/399, 123/332
• US Class Current: 701/54
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/106 Rate of change
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/1061 Output power
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: F16H 2059/084 Economy mode
• CPC Class Codes: F16H 2059/743 using engine performance or power for control of gearing transmission input torque F16H2059/147
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/04 Smoothing ratio shift
• CPC Class Codes: F16H 61/66 specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38

Abstract

An internal combustion engine (E) has associated control devices (ECU, GSCU, SCU) for controlling the engine in a manner such that the engine delivers a driving torque (CM) which is variable in dependence on predetermined measured parameters, in particular on the position (α) of the accelerator pedal (AP), and sensors (S1, S2) for detecting the position (α) of the accelerator pedal (AP), and the rate of rotation (ω_M) of the shaft (M) of the engine (E) or the forward speed (v) of the motor vehicle, respectively. The control system (ECU, GSCU, SCU) associated with the engine (E) is arranged:—to acquire from the sensors (S1, S2) the position (α) of the accelerator pedal (AP) and the rate of rotation (ω_M) of the engine (E), or the forward speed (v) of the motor vehicle;—to determine, in accordance with predetermined methods, the power (P_T) to be applied to the driving wheels in dependence on the measured position (α) of the accelerator pedal (AP) and on the calculated or acquired forward speed (v) of the vehicle, and to calculate, in dependence on the value determined for the power (P_T) to be applied to the driving wheels and on the forward speed (v) of the vehicle, the driving torque (C_MREF) which should correspondingly be delivered by the engine (E), and to control the engine (E) in a manner such that it delivers the driving torque (C_MREF) thus calculated.

Claims

1. A drive control system for a motor vehicle, provided with:

an internal combustion engine (E) with associated control means (ECU, GSCU, SCU) for operating the engine in a manner such that the engine (E) delivers a driving torque (C_M) which is variable in dependence on predetermined measured parameters, in particular, on the position (α

) of the accelerator pedal (AP), and with

sensor means (S1, S2) for providing electrical signals indicative of the position (α

) of the accelerator pedal (AP) and of the rate of rotation (ω

_M) of the shaft (M) of the engine (E) or of the forward speed (v) of the motor vehicle, respectively,

the control means (ECU, GSCU, SCU) being arranged;

to acquire from the sensor means (S1, S2) the position (α

) of the accelerator pedal (AP) and the rate of rotation (ω

_M) of the shaft (M) of the engine (E), or the forward speed (v) of the motor vehicle,

to determine the power (P_T) to be applied to the driving wheels in dependence on the measured position (α

) of the accelerator pedal (AP) and on the calculated or acquired forward speed (v) of the vehicle;

characterized in that said control means (ECU, GSCU, SCU) are arranged to calculate, in dependence on the value determined for the power (PT) to be applied to the driving wheels and on the forward speed (v) of the vehicle, the driving torque (C_MREF) which should correspondingly be delivered by the engine (E), and to control the engine (E) in a manner such that it delivers the driving torque (C_MREF) thus calculated the system further comprising first memory means (M1) which are associated with the control means and in which there are stored data defining the power (P_T) to be applied to the driving wheels of the vehicle in dependence on the position (α

) of the accelerator pedal (AP) and on the longitudinal speed (v) of the vehicle, the control means being arranged to determine the power (P_T) to be applied to the driving wheels on the basis of the data held in the first memory means (M1).

2. A control system according to claim 1, for a motor-vehicle provided with

a servo-assisted gearbox (G) with an input shaft (P) which can be coupled to the shaft (M) of the engine (E) by means of a servo-assisted clutch (F), first and second electrically-operated actuator means (B, A) being associated with the gearbox (G) and with the clutch (F), respectively,

and further sensor means (Sn) for supplying electrical signals indicative of the transmission ratio (τ ) engaged in the gearbox (G),

the system being characterized in that the control means are arranged to implement an automatic drive control procedure in dependence on the position ( ) of the accelerator pedal (AP);

the control means being arranged, in particular,

to acquire, from the sensor means (S1, S2, Sn) the position (α

) of the accelerator pedal (AP), the rate of rotation (ω

_M) of the shaft (M) of the engine (E), or the forward speed of the motor vehicle (v), and the transmission ratio (τ

_M) put into effect by the gearbox (G);

to calculate or to acquire the forward speed (v) of the vehicle;

to determine, in accordance with predetermined methods, the power (P_T) to be applied to the driving wheels in dependence on the detected position (α

) of the accelerator pedal (AP) and on the forward speed (v) of the vehicle;

to calculate, in dependence on the value determined for the power (P_T) to be applied to the driving wheels and on the forward speed (v) of the vehicle, the driving torque (C_MREF) which should correspondingly be delivered by the engine (E);

to determine, in accordance with predetermined methods, the transmission ratio (τ

_n) to be put into effect by the gearbox (G), in dependence on the value determined for the power (P_T) to be applied to the driving wheels and on the forward speed (v) of the vehicle, and

to check whether the transmission ratio (τ

_n) to be put into effect corresponds to the transmission ratio engaged (τ

_i), and

if the result is positive, to control the engine (ECU) in a manner such that it delivers the calculated driving torque (C_MREF), and

if the result is negative, to control the implementation of the change to the transmission ratio (τ

_n) to be put into effect, controlling the engine (ECU) in a manner such that, upon completion of the operation to change to the transmission ratio (τ

_n) to be put into effect, the engine (E) delivers a driving torque substantially equal to the driving torque (C_MREF) calculated.

3. A control system according to claim 2, comprising second memory means (M2) which are associated with the control means and in which data are stored for defining the transmission ratio or gear (τ

_n) to be put into effect by the gearbox (G) in dependence on the power (P_T) to be applied to the driving wheels and on the longitudinal speed (v) of the vehicle, and in which the control means are arranged to determine the transmission ratio (τ

_n) to be put into effect on the basis of the data held in the second memory means (M2).

4. A control system according to claim 2, in which the control means are arranged:

to determine, in accordance with predetermined methods, a reference value (J_REF) for the time differential of the longitudinal acceleration (a_x) of the motor vehicle, in dependence on the value determined for the power (P_T) to be applied to the driving wheels,

to generate reference signals indicative of a reference driving torque (C_MREF), and

to control the change to the transmission ratio (τ

_n) to be put into effect in a manner such as to keep the time derivative of the longitudinal acceleration (a_x) of the vehicle substantially constant and equal to the reference value (J_REF).

5. A control system according to claim 4, comprising third memory means (M3) which are associated with the control means and in which predetermined values of the time differential of the longitudinal acceleration (a_x) of the vehicle as a function of the power (P_T) to be applied to the driving wheels are stored.

6. A control system according to claim 4, in which the control means are arranged to control the engine (E) and the actuator means (A, B) associated with the clutch (F) and with the gearbox (G) during a gear shifting stage in a manner such that the driving torque (C_M) delivered by the engine (E) and the torque (C_F) transmitted by the clutch (F) to the gearbox (G) vary in accordance with respective substantially linear curves.

7. A control system according to claim 3, in which the second memory means (M2) contain, in the power to ground/forward speed plane (P_T/v), data representative of gear shifting boundary lines, a boundary line associated with a shift from one gear to the immediately higher (lower) gear being different from that associated with the reverse change.

8. A control system according to claim 1, comprising manually-operated selector means (M/A) for supplying the control means with signals providing selectively for manual drive control or for automatic drive control.