Hybrid electric vehicle control strategy to achieve maximum wide open throttle acceleration performance

• US 6,553,287 B1
• Filed: 10/19/2001
• Issued: 04/22/2003
• Est. Priority Date: 10/19/2001
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Freyermuth, Vincent, Kuang, Ming Lang, Supina, Joseph Gerald
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): MANCHO, RONNIE M
• Application Number:
  US09/682,793
• Time in Patent Office: 550 Days
• Field of Search: 701/22, 701/1, 701/62, 701/64, 701/55, 477/169, 477/110, 477/3, 477/143, 477/155, 290/45, 290/40.C, 180/65.2, 180/165, 180/65.3, 180/197, 180/69.6, 318/9, 318/139, 475/1, 475/10, 475/211, 192/220.4, 743/34, 743/375, 744/731.1
• US Class Current: 701/22
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• 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 2510/083 Torque
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

The invention is a controller for a hybrid electric vehicle (HEV) to meet driver expectation when forward wide open throttle (WOT) acceleration is requested while optimizing the total powertrain system efficiency and performance, especially when the engine is not even running. The controller can consider accelerator position, PRNDL position, and vehicle speed and start the engine if an estimated sum torque of a traction motor and generator motor is less than the calculated sum torque output of the traction motor and the engine at any given speed. Other control variables can include battery condition such as operating capacity, temperature, and state of charge. A constant can be added to allow a prestart of the engine to assure it is available when needed to maintain vehicle WOT acceleration requests.

Claims

1. A control system for a powersplit hybrid electric vehicle PSHEV powertrain powered by at least one of an engine, a traction motor, and a generator motor comprising:

an accelerator position sensor;

a vehicle speed sensor;

a PRNDL position sensor;

a battery for powering the traction motor and generator motor and receiving power from the generator motor; and

a vehicle system control (VSC) to control the vehicle powertrain, the VSC

receiving input from the accelerator position sensor, vehicle speed sensor, and PRNDL position sensor

making a determination of whether full forward acceleration is requested,

making a determination of whether the engine is running, estimating the sum torque of the traction motor and the generator motor if the engine is not running,

calculating the maximum sum torque output of the traction motor and the engine,

comparing the estimated sum torque of the traction motor and the generator motor with the calculated sum torque output of the traction motor and the engine, and

starting the engine if the estimated sum torque of the traction motor and the generator motor is less than the calculated sum torque output of the traction motor and the engine for a given vehicle speed.

2. The control system of claim 1 further comprising battery sensors connected to the battery and VSC.

3. The control system of claim 2, wherein the battery sensors sense battery operating capacity, temperature and state of charge.

4. The control system of claim 2 wherein the estimating of the sum torque of the traction motor and the generator motor and the calculating of the maximum sum torque output of the traction motor and the engine use input from the battery sensors.

5. The control system of claim 2 wherein the estimating of the sum torque of the traction motor and the generator motor and the calculating of the maximum sum torque output of the traction motor and the engine use a constant to allow a prestart of the engine.

6. A method to control a powersplit hybrid electric vehicle PSHEV powertrain by at least one of an engine, a traction motor, and a generator motor comprising:

sensing accelerator position;

sensing vehicle speed;

sensing PRNDL position;

receiving, storing and providing power to the traction motor and generator motor; and

controlling the vehicle powertrain using a vehicle system control (VSC), including

receiving input from the accelerator position sensor, vehicle speed sensor, and PRNDL position sensor

making a determination of whether full forward acceleration is requested,

making a determination of whether the engine is running, estimating the sum torque of the traction motor and the generator motor if the engine is not running,

calculating the maximum sum torque output of the traction motor and the engine,

comparing the estimated sum torque of the traction motor and the generator motor with the calculated sum torque output of the traction

motor and the engine, and

starting the engine if the estimated sum torque of the traction motor and the generator motor is less than the calculated sum torque output of the traction motor and the engine for a given vehicle speed.

7. The method of claim 6 further comprising the step of sensing battery condition with the VSC.

8. The method of claim 7, wherein the battery sensing step senses battery operating capacity, temperature and state of charge.

9. The method of claim 7 wherein the step of estimating the sum torque of the traction motor and the generator motor and the calculating of the maximum sum torque output of the traction motor and the engine includes using battery sensing.

10. The method of claim 7 wherein the step of estimating the sum torque of the traction motor and the generator motor and the calculating of the maximum sum torque output of the traction motor and the engine includes using a constant to allow a prestart of the engine.