Method for driving a hybrid traction chain based on the battery charge state

• US 8,392,042 B2
• Filed: 09/30/2008
• Issued: 03/05/2013
• Est. Priority Date: 10/03/2007
• Status: Expired due to Fees

• Current Assignee: Peugeot Citroen Automobile SA (Stellantis NV)
• Original Assignee: Peugeot Citroen Automobile SA (Stellantis NV)
• Inventors: Noiret, Christian
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US12/681,618
• Publication Number:
  US 20100280694A1
• Time in Patent Office: 1,617 Days
• Field of Search: 701/22, 180/65.29, 180/65.285, 180/65.21, 180/65.265, 180/65.28, 180/65.25, 180/65.6, 180/65.245, 180/65.27, 180/65.23, 180/65.225, 180/165, 477/3, 903/915, 903/905, 903/903, 903/947, 903/945, 320/132, 320/104, 475/5, 318/153, 318/140, 322/16
• US Class Current: 701/22
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor
• CPC Class Codes: B60W 10/24 including control of energy storage means
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

The control method for a hybrid drive system of a vehicle includes (1) acquiring the driver'"'"'s acceleration desire for determining the power for the corresponding wheel (Pwheel), the charge level of the battery (SOC) between a minimum (SOCmin) and a maximum (SOCmax) thresholds for a predetermined traction mode, and the available braking power (Pfrein) for deciding between electric or dissipative braking; (2) managing the charge (SOC) for, based on a first (SOC1 bmin) and a second (SOC2 bmin) minimum thresholds of the charge (SOC) and the driver'"'"'s requested wheel power (Pwheel), either imposing a battery recharge or setting input parameters for the traction mode selection; and (3) selecting the traction mode, based on the battery power actually available (Pbat), the driver'"'"'s requested wheel power (Pwheel), and the maximum power available at the thermal engine output (Pmthmax), for selecting the traction mode most adapted to the actual situation of the vehicle.

Claims

1. Control method for a hybrid drive system of a vehicle, in particular a motor vehicle, the hybrid drive system including (i) a heat engine, (ii) at least one electric drive machine adapted to operate as a motor or as a generator and enabling combustion and/or electric drive modes, (iii) a braking system adapted to implement regenerative and/or dissipative braking, and (iv) a battery with a set nominal electric power (bat), which method comprises the following steps:

a first step of obtaining an acceleration request of the driver in order to determine a corresponding power at the wheel (Pwheel), obtaining a state-of-charge level of the battery (SOC), and obtaining a braking power at the wheel requested by the driver (Pbrake), which makes it possible to decide whether it is appropriate to apply electric or dissipative braking;

a second step of controlling the state of charge (SOC) of the battery, comprising, as a function of a battery recharge requirement status indicator (Pmin),

when the power requested at the wheel (Pwheel) is greater than a maximum power available from the heat engine (Pengmax), calculating an available battery power (Pbat) by multiplying a nominal battery power (bat) by a first battery charge coefficient (Coef1) whose value varies between 0 and 1 according to a first preestablished law, between a first set minimum threshold (SOC1min) of the battery state of charge, which is greater than an allowed minimum threshold (SOCmin), and a first set maximum threshold (SOC1max), which is less than an allowed maximum threshold (SOCmax), and

when the power requested at the wheel (Pwheel) is less than the maximum power available from the heat engine (Pengmax), calculating the available battery power (Pbat) by multiplying the nominal battery power (bat) by a second battery charge coefficient (Coef2) whose value varies between 0 and 1 according to a second preestablished law, between a second set minimum battery state-of-charge threshold (SOC2min), which is greater than the allowed minimum threshold (SOCmin), and a second set maximum threshold (SOC2max), which is less than the allowed maximum threshold (SOCmax); and

a third step of choosing the drive mode, as a function of the available battery power (Pbat), the drive power at the wheel requested by the driver (Pwheel), and the maximum power available from the heat engine (Pengmax), by setting a most appropriate drive mode of the hybrid drive system for the vehicle operating situation, which is selected among a set of available drive modes of the hybrid drive system including;

pure electric;

combustion-only;

combustion and electric;

combustion and battery recharge;

battery recharge at standstill; and

use of regenerative braking authorized or prohibited.

2. Method according to claim 1, wherein the drive mode selection step comprises choosing pure electric drive mode when the power at the wheel requested by the driver (Pwheel) is less than the available battery power (Pbat) and when the battery state of charge (SOC) is greater than the second set minimum threshold (SOC2min).

3. Method according to claim 1, wherein the drive mode selection step comprises choosing combustion drive mode with battery recharge when the power at the wheel requested by the driver (Pwheel) is greater than the available battery power (Pbat) and when the battery state of charge (SOC) is less than the second set minimum threshold (SOC2min), and when the power at the wheel requested by the driver (Pwheel) is less than the power available from the heat engine (Pengmin).

4. Method according to claim 1, wherein the drive mode selection step comprises choosing combustion-only drive mode without battery recharge when the power at the wheel requested by the driver (Pwheel) is greater than the available battery power (Pbat) and when the battery state of charge is greater than the second set minimum threshold (SOC2min).

5. Method according to claim 1, wherein the drive mode selection step comprises choosing combustion-only drive mode without battery recharge when the power at the wheel requested by the driver (Pwheel) is greater than the maximum power available from the heat engine (Pengmax), and when the battery state of charge (SOC) is less than the first set minimum threshold (SOC1min).

6. Method according to claim 1, wherein the drive mode selection step comprises choosing combustion and electric drive modes without battery recharge when the power at the wheel requested by the driver (Pwheel) is greater than the maximum power available from the heat engine (Pengmax), and when the battery state of charge (SOC) is greater than the first set minimum threshold (SOC1min).

7. Method according to claim 1, comprising, when electric braking is used and reaches the maximum power available through the electric machine, adding dissipative braking as needed.

8. Method according to claim 1, wherein electric braking is prohibited when the battery charge level (SOC) is greater than the second set maximum threshold (SOC2max).

9. Method according to claim 1, comprising, when the driver is operating neither the brake nor the accelerator, ordering a minimum power called ramping power (Pramp) generated by the hybrid drive system.

10. Method according to claim 1, wherein the control step comprises necessarily triggering the battery to recharge when the battery state of charge (SOC) is less than the first set minimum threshold (SOC1min) and when the power requested at the wheel by the driver (Pwheel) is zero.

11. Method according to claim 1, comprising adding in a threshold correction (CSOC) respectively to the first and second battery state-of-charge thresholds (SOC1min, SOC1max and SOC2min, SOC2max) when the battery recharge requirement status indicator (Pmin) is equal to the minimum power level needed from the heat engine if battery recharge by the heat engine is required (Pengmin), to prevent any oscillation between pure electric drive mode and combustion drive mode.