Process and apparatus for braking a hybrid-drive motor vehicle

• US 5,788,597 A
• Filed: 12/22/1995
• Issued: 08/04/1998
• Est. Priority Date: 12/23/1994
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Boll, Wolf, Antony, Peter, Botzelmann, Herbert
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): JENSEN, NATHAN
• Application Number:
  US08/575,950
• Time in Patent Office: 956 Days
• Field of Search: 477/4, 477/184, 477/185, 477/188, 180/65.2, 180/65.3, 180/65.4, 180/165
• US Class Current: 477/4
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/20 Braking by supplying regenerated power to the prime mover of vehicles comprising engine-driven generators
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 2270/602 ABS features related thereto
• CPC Class Codes: B60T 2270/606 Axle differential or center differential features related thereto
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 : including control of braking systems
• 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 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F02D 9/06 : Exhaust brakes
• CPC Class Codes: H02J 2310/48 : for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/14 : for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: H02J 7/1415 : with a generator driven by a prime mover other than the motor of a vehicle
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

In a process and apparatus for braking a hybrid drive vehicle, kinetic vehicular energy is converted by the driving electric motor into electrical power, which alternatively can be absorbed by charging a traction battery or by driving a combustion engine via a generator coupled to the engine, which is functioning as a motor. According to the invention, engine braking is activated if the traction battery is fully charged, if its temperature lies outside a predetermined charging temperature range, or if the charging current due to the electrical power supplied by the driving electric motor exceeds a predetermined limit value.

Claims

1. A process for braking a hybrid drive motor vehicle having a combustion engine, a generator mechanically coupled with the engine, and a driving electric motor electrically coupled to the generator and to a traction battery, wherein during a braking procedure, the driving electric motor, in generator operation, converts kinetic energy into electric energy, which is alternatively absorbed by charging the traction battery or by driving the combustion engine, said process comprising the steps of:

monitoring the charge state, temperature and charging current of the traction battery; and

activating engine braking upon the occurrence of at least one of the following;

the traction battery is fully charged;

the temperature of the traction battery lies outside a predetermined charging temperature range; and

the charging current intensity for the traction battery, due to the electric power supplied by the driving electric motor, exceeds a predetermined limit value.

2. The process according to claim 1, comprising the further steps of adjusting engine braking action by controlling an opening angle of a throttle valve of the engine as a function of at least one of the following:

required engine braking power, a momentary operation mode of the hybrid drive, and required brake power dynamics.

3. The process according to claim 1, comprising the further steps of:

bringing the engine to a selectable engine braking speed at the beginning of an engine braking demand; and

controlling the engine in an engine braking operation.

4. The process according to claim 3, wherein the engine braking speed is chosen as a function of at least one of the following:

state of the traction battery, vehicle speed, and pedal travel of a brake pedal of the vehicle.

5. An apparatus for braking a hybrid drive motor vehicle having a combustion engine, a generator mechanically coupled with the engine, and a driving electric motor electrically coupled to the generator and to a traction battery, wherein the driving electric motor carries out a drive function for the engine, and the engine is designed to carry out an engine braking function, said apparatus comprising:

a brake pedal sensor for detecting position of a brake pedal of said vehicle;

a traction battery monitoring unit which monitors an operating state of the traction battery; and

a hybrid drive control unit coupled to receive output signals from said brake pedal sensor, a slip control system and said traction battery monitoring unit, said output signals from said traction battery monitoring unit including information concerning at least one charge state, temperature, and charging current of said traction battery;

said hybrid drive control unit including means for triggering at least one of battery charging braking and engine braking in response to a signal from said brake pedal signal, and for triggering engine braking upon the occurrence of at least one of the following;

the recorded battery charge state has exceeded a predetermined full charge limit value;

the battery temperature lies outside a predetermined charging temperature range; and

the recorded charging current exceeds a predetermined charging current limit value.

6. The apparatus according to claim 5, further comprising a throttle valve adjusting member of said engine (7), which can be controlled by the hybrid drive control unit (10) in engine braking operation.