Torque modulation for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10612475-B2
Application number	US-201415032125-A
Country	US
Kind code	B2
Filing date	Oct 16, 2014
Priority date	Oct 28, 2013
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A method and apparatus for continually and rapidly adjusting the output torque of an engine according to a torque demand uses an active tappet to vary the instant air charge in a combustion chamber. The invention allows substantially efficient combustion throughout the engine operating map. Various methods of changing the charge of air are disclosed.

First claim

The invention claimed is:

1. A method of continuous modulation of torque output of a multi-cylinder internal combustion engine, each cylinder having a combustion chamber, at least one inlet valve for each combustion chamber and an active tappet for each inlet valve for activating a respective said inlet valve, the method comprising:
for each successive combustion event in said combustion chamber
a) determining a change of torque demand relative to an immediately preceding combustion event,
b) controlling said active tappet to provide a change of air charge in a respective said combustion chamber in dependence on each change of torque demand relative to the immediately preceding combustion event, said change of air charge being commensurate to said change of torque demand relative to the immediately preceding combustion event, wherein if the change of torque demand is an increase said active tappet is controlled to increase the air charge and if the change of torque demand is a decrease said active tappet is controlled to decrease the air charge, wherein each active tappet is individually commanded by an electronic control unit of said internal combustion engine to change a charge of air available for combustion in a respective cylinder on a combustion event by combustion event basis, wherein said active tappet is controlled to increase the air charge to said combustion chamber at least by increasing valve lift when said change of torque demand is an increase of torque demand, to cause, in part, the torque output of the internal combustion engine to increase to continuously track said increase of torque demand, and
c) commanding a selected type of combustion appropriate to said air charge in said combustion chamber by adjustment of timing of commencement of combustion, wherein a timing of an ignition spark is advanced when the change of torque demand is an increase of torque demand, to speed up an increase in the torque output to track said increase of torque demand.

2. A method according to claim 1 , including retarding the timing of the ignition spark by less than 10 ° when the change of torque demand is a decrease.

3. A method according to claim 1 , wherein said change of air charge is provided by one or more of:
changing a lift of said tappet,
changing a duration of opening of said inlet valve by control of said tappet,
changing a timing of opening of said inlet valve by control of said tappet,
changing a timing of closing of said inlet valve by control of said tappet,
changing an overlap of said inlet valve and an exhaust valve of said combustion chamber, by control of said tappet.

4. A method according to claim 1 , wherein said active tappet permits a variation of an immediately succeeding valve opening in consequence of a determination of a change in torque demand after a preceding valve opening.

5. A method of claim 1 , wherein said active tappet comprises a hydraulic chamber having an electrically commanded valve to vary an instant volume of the hydraulic chamber.

6. A method according to claim 5 , wherein said hydraulic chamber is provided with an unobstructed inlet flow of liquid oil, and the electrically commanded valve is a solenoid controlled bleed valve to vary outlet flow from said hydraulic chamber.

7. A control system, comprising:
an electronic control unit having a processor and a memory associated with the processor, the processor being configured for electronically commanding an active tappet of an inlet valve of a cylinder of an engine according to a torque demand parameter contained in the memory, the cylinder having a combustion chamber, the processor being configured for continuous modulation of torque output of the engine, comprising
for each successive combustion event in said combustion chamber:
a) determining a change of torque demand relative to an immediately preceding combustion event, b) controlling said active tappet to provide a change of air charge in said combustion chamber in dependence on each change of torque demand relative to the immediately preceding combustion event, said change of air charge being commensurate to said change of torque demand relative to the immediately preceding combustion event, wherein if the change of torque demand is an increase said active tappet is controlled to increase the air charge and if the change of torque demand is a decrease said active tappet is controlled to decrease the air charge, wherein the active tappet is individually commanded by the electronic control unit to change a charge of air available for combustion in the cylinder on a combustion event by combustion event basis, wherein said active tappet is controlled to increase the air charge to said combustion chamber at least by increasing valve lift when said change of torque demand is an increase of torque demand, to cause, at least in part, the torque output of the internal combustion engine to increase to continuously track said increase of torque demand, and
c) commanding a selected type of combustion appropriate to said air charge in said combustion chamber by adjustment of timing of commencement of combustion, wherein a timing of an ignition spark is advanced when the change of torque demand is an increase of torque demand to speed up an increase in the torque output to track said increase of torque demand.

8. A reciprocating piston gasoline engine, comprising:
a plurality of cylinders, each cylinder having a combustion chamber;
an inlet valve for each cylinder; and
an active tappet for each said inlet valve, said engine being adapted for operation according to a method of continuous modulation of torque output of the engine, the method comprising:
for each successive combustion event in said combustion chamber:
a) determining a change of torque demand relative to an immediately preceding combustion event,
b) controlling said active tappet to provide a change of air charge in a respective said combustion chamber in dependence on each change of torque demand relative to the immediately preceding combustion event, said change of air charge being commensurate to said change of torque demand relative to the immediately preceding combustion event, wherein if the change of torque demand is an increase said active tappet is controlled to increase the air charge and if the change of torque demand is a decrease said active tappet is controlled to decrease the air charge, wherein each active tappet is individually commanded by an electronic control unit of said engine to change a charge of air available for combustion in a respective cylinder on a combustion event by combustion event basis, wherein said active tappet is controlled to increase the air charge to said combustion chamber at least by increasing valve lift when said change of torque demand is an increase of torque demand to cause, in part, the torque output of the engine to increase to continuously track said increase of torque demand, and
c) commanding a selected type of combustion appropriate to said air charge in said combustion chamber by adjustment of timing of commencement of combustion, wherein a timing of an ignition spark is advanced when the change of torque demand is an increase of torque demand to speed up an increase in the torque output to track said increase of torque demand.

9. A vehicle incorporating the engine of claim 8 , and an electronic control system for implementing the method.

10. A method according to claim 1 , wherein
the change of torque demand is a torque down demand; and
the adjustment of timing of commencement of combustion comprises retarding the timing of commencement of combustion relative to a timing for most efficient combustion, by less than an amount of permissible retardation.

Assignees

• Jaguar Land Rover Ltd

Inventors

• Brockley Nick

Classifications

• F02D13/0223

  Variable control of the intake valves only · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• F01L1/25

  between cam and valve stem · CPC title

• F02D37/02

  one of the functions being ignition · CPC title

• F02D2250/22

  by keeping a torque reserve, i.e. with temporarily reduced drive train or engine efficiency · CPC title