Systems and methods for reducing noise, vibration, and/or harshness during engine shutdown and restart

Patent metadata

Field	Value
Publication number	US-10746255-B2
Application number	US-201815975586-A
Country	US
Kind code	B2
Filing date	May 9, 2018
Priority date	May 9, 2018
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

In some embodiments of the present disclosure, an electric motor is used to generate correction torques to counteract unwanted torque pulses generated by an internal combustion engine during startup and/or shutdown. In some embodiments, the electric motor may be mounted to an accessory drive such as a power take-off mechanism or a front end accessory drive (FEAD). In some embodiments, the correction torques may be used to enforce an engine speed target profile for startup or shutdown, and may be determined using a feedback control loop based on the engine speed. The correction torques help to reduce or eliminate noise, vibration, and/or harshness (NVH) during startup and/or shutdown.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A vehicle, comprising:
an internal combustion engine;
an electric motor;
an accessory drive having a drive shaft and an output shaft, wherein the drive shaft of the accessory drive is coupled to an output of the internal combustion engine, and the output shaft of the accessory drive is coupled to the electric motor; and
an electronic control unit (ECU) configured to:
initiate a shutdown process for the internal combustion engine;
receive, at a first time, a first engine speed of the internal combustion engine;
select, based on the first engine speed, a first engine profile from a plurality of engine profiles;
cause initiation of a timer; and
cause the electric motor to generate torque to counteract vibration induced by the internal combustion engine during the shutdown process, wherein causing the electric motor to generate the torque comprises at least:
determining, for a second time following the first time, an expected engine speed based on the first engine profile and an elapsed time of the timer;
determining a second engine speed at the second time; and
determining the torque based on the second engine speed and the expected engine speed.

2. The vehicle of claim 1 , further comprising:
an engine speed sensor configured to provide engine speed values to the ECU at a rate of at least 50 values per second or at least 60 values per revolution of the internal combustion engine.

3. The vehicle of claim 2 , wherein causing the electric motor to generate torque to counteract vibration induced by the internal combustion engine during the shutdown process includes:
using a feedback control loop to determine a correction torque to be generated by the electric motor.

4. The vehicle of claim 3 , wherein the feedback control loop is a proportional-integral-derivative (PID) control loop.

5. The vehicle of claim 3 , wherein a process variable of the feedback control loop is the engine speed value, wherein a control variable of the feedback control loop is the correction torque, and wherein a setpoint of the feedback control loop is an expected engine speed.

6. The vehicle of claim 5 , wherein the expected engine speed is adjusted over time according to an engine speed target profile.

7. A method of reducing vibration generated by an internal combustion engine, the method comprising:
detecting, by an engine control unit (ECU), a condition that causes a transition of an engine speed of the engine from a first engine speed to a second engine speed;
selecting, by the ECU and based on the first engine speed, an engine speed target profile from a plurality of engine speed target profiles for transitioning the engine speed of the engine, wherein the engine speed target profile specifies a plurality of expected engine speeds at a plurality of points in time following detection of the instruction;
initiating a timer;
monitoring, by the ECU, the engine speed of the engine;
determining, by the ECU, a correction torque to drive the engine speed toward an expected engine speed at a given point in time according to the engine speed target profile and an elapsed time of the timer; and
causing, by the ECU, an electric motor to apply the correction torque.

8. The method of claim 7 , wherein monitoring the engine speed of the engine includes receiving engine speed values from an engine speed sensor at a rate of at least 50 values per second or at least 60 values per revolution of the engine; and
wherein the correction torque is determined for each received engine speed value.

9. The method of claim 7 , wherein the first engine speed is an operating engine speed and the second engine speed is a stopped engine speed; or
the first engine speed is a stopped engine speed and the second engine speed is an operating engine speed.

10. The method of claim 7 , wherein the correction torque is positive when the engine speed is lower than the expected engine speed, and wherein the correction torque is negative when the engine speed is higher than the expected engine speed.

11. The method of claim 7 , wherein the determining correction torque includes using a feedback control loop.

12. The method of claim 11 , wherein the feedback control loop includes a proportional-integral-derivative (PID) control loop.

13. The method of claim 11 , wherein a process variable of the feedback control loop is the engine speed, wherein a control variable of the feedback control loop is the correction torque; and wherein a setpoint of the feedback control loop is determined by the engine speed target profile.

14. A non-transitory computer-readable medium having computer-executable instructions stored thereon that, in response to execution by an engine control unit (ECU), cause the ECU to perform actions for reducing vibration generated by an internal combustion engine, the actions comprising:
detecting, by the ECU, a condition that causes a transition of an engine speed of the engine from a first engine speed to a second engine speed, wherein detecting the condition comprises detecting vibration from a vibration sensor;
selecting, by the ECU and based on the first engine speed, an engine speed target profile from a plurality of engine speed target profiles for transitioning the engine speed of the engine, wherein the engine speed target profile specifies a plurality of expected engine speeds at a plurality of points in time following detection of the instruction;
initiating a timer;
monitoring, by the ECU, the engine speed of the engine;
determining, by the ECU, a correction torque to drive the engine speed toward an expected engine speed at a given point in time according to the engine speed target profile and an elapsed time of the timer; and
causing, by the ECU, an electric motor to apply the correction torque.

15. The computer-readable medium of claim 14 , wherein monitoring the engine speed of the engine includes receiving engine speed values from an engine speed sensor at a rate of at least 50 values per second or at least 60 values per revolution of the engine; and
wherein the correction torque is determined for each received engine speed value.

16. The computer-readable medium of claim 14 , wherein the first engine speed is an operating engine speed and the second engine speed is a stopped engine speed; or
the first engine speed is a stopped engine speed and the second engine speed is an operating engine speed.

17. The computer-readable medium of claim 14 , wherein the correction torque is positive when the engine speed is lower than the expected engine speed, and wherein the correction torque is negative when the engine speed is higher than the expected engine speed.

18. The computer-readable medium of claim 14 , wherein determining the correction torque includes using a feedback control loop.

19. The computer-readable medium of claim 18 , wherein the feedback control loop includes a proportional-integral-derivative (PID) controller.

20. The computer-readable medium of claim 18 , wherein a process variable of the feedback loop is the engine speed, wherein a control variable of the feedback loop is the correction torque; and wherein a setpoint of feedback control loop is determined by the engine speed target profile.

Assignees

• Paccar Inc

Inventors

• Gerty Michael D
• Vadlamani Uday

Classifications

• Y02T10/62

  Hybrid vehicles · CPC title

• F02D2250/28

  Control for reducing torsional vibrations, e.g. at acceleration · CPC title

• B60K25/06

  from the transmission power take-off · CPC title

• B60K1/00

  Arrangement or mounting of electrical propulsion units (B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00) · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title