Opportunistic charging of hybrid vehicle battery

Patent metadata

Field	Value
Publication number	US-10155511-B2
Application number	US-201615216747-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	May 7, 2012
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

A control system for a modular hybrid electric vehicle operates an internal combustion engine at a torque level above the driver demanded torque improving the engine's efficiency. A traction motor driveably connected to the engine is operated at a torque level such that the combined torque satisfies the driver demand. The traction motor torque is limited to avoid inefficient combinations of speed and torque at which the motor is inefficient. During idle operation, the traction motor is operated at a torque determined from a battery state of charge and the engine is operated to maintain a predetermined speed. If the engine speed drops below a threshold, motor torque is adjusted to reduce the load on the engine to avoid stalling.

First claim

The invention claimed is:

1. A method comprising:
while a motor is driveably connected to an engine by a first clutch and driveably disconnected from a transmission gearbox by a second clutch, operating the motor to generate a first charging torque based on a state of charge of a battery; and
in response to an engine speed decreasing below a threshold, further operating the motor to adjust the first charging torque to decrease a load on the engine.

2. The method of claim 1 further comprising:
engaging the second clutch to driveably connect the motor to the transmission gearbox;
controlling the engine to produce an engine torque based on the engine speed and the state of charge; and
further operating the motor to generate a second charging torque such that a sum of the second charging torque and the engine torque satisfies a driver demanded net torque.

3. The method of claim 2 wherein the driver demanded net torque is based on the engine speed and an accelerator pedal position.

4. The method of claim 3 further comprising:
further operating the motor to generate a minimum charging torque, wherein the minimum charging torque is based on the engine speed.

5. The method of claim 3 further comprising:
further operating the motor to generate a positive torque to assist the engine in satisfying the driver demanded net torque.

6. A vehicle powertrain comprising:
an engine;
a motor electrically connected to a battery;
a first clutch configured to selectively couple the engine to the motor;
a second clutch configured to selectively couple the motor to a gearbox; and
a controller configured to
while the first clutch is engaged and the second clutch is disengaged, operate the motor to generate a first charging torque based on a state of charge of the battery, and
respond to an engine speed decreasing below a threshold by adjusting the first charging torque to decrease a load on the engine.

7. The vehicle powertrain of claim 6 further wherein the controller is further configured to
engage the second clutch,
control the engine to produce an engine torque based on the engine speed and the state of charge, and
control the motor to generate a second charging torque such that a sum of the second charging torque and the engine torque satisfies a driver demanded net torque.

8. The vehicle powertrain of claim 7 wherein the driver demanded net torque is based on the engine speed and an accelerator pedal position.

9. The vehicle powertrain of claim 7 wherein the controller is further programmed to control the motor to generate a positive torque to assist the engine in satisfying the driver demanded net torque.

Assignees

• Ford Global Tech Llc

Inventors

• Yamazaki Mark Steven
• Lear Christopher Alan
• Connolly Francis Thomas

Classifications

• B60K6/48

  Parallel type · CPC title

• B60W2510/0642

  Idle condition · CPC title

• B60W2510/244

  Charge state · CPC title

• B60W10/08

  including control of electric propulsion units, e.g. motors or generators · CPC title

• B60W2556/00

  Input parameters relating to data · CPC title