Method and system for controlling a turbocharged engine during an upshift

Patent metadata

Field	Value
Publication number	US-9816448-B2
Application number	US-201414787066-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Apr 30, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

A method for propulsion of a vehicle ( 100 ): The vehicle ( 100 ) includes a combustion engine ( 101 ), and a gearbox ( 103 ) that can be adjusted to a number of gear ratios for transfer of force between the combustion engine ( 101 ) and at least one driving wheel ( 113, 114 ), at least one combustion chamber with at least one inlet for the supply of combustion gas and at least one outlet for the evacuation of an exhaust gas flow that has resulted from combustion in the combustion chambers and a turbocharger unit ( 203 ) for pressurizing the combustion gas. In the method, during the change of gear from a first higher gear ratio to a second lower gear ratio, the rate of revolution of the combustion engine ( 101 ) is reduced, to control the turbocharger unit such that the pressure of the combustion gas is reduced, to increase the pressure at the outlet by constriction of the exhaust gas flow, and when the rate of revolution of the combustion engine ( 101 ) has at least partially fallen towards a second rate of revolution, to control the turbocharger unit such that the combustion gas pressure is increased. Also a system and a vehicle including the system.

First claim

The invention claimed is:

1. A method for propulsion of a vehicle, wherein the vehicle comprises:
a combustion engine, a gearbox adjustable to a number of gear ratios for transfer of a force between the combustion engine and at least one driving wheel, wherein the combustion engine comprises at least one combustion chamber with at least one inlet for supply of combustion gas and at least one outlet for evacuation of an exhaust gas flow that has resulted from combustion in the combustion chamber, and a turbocharger unit for pressurisation of the combustion gas, the turbocharger unit comprising a turbine with adjustable guide rails and a compressor;
the method comprising, during a change of gear from a first higher gear ratio to a second lower gear ratio, a rate of revolution of the combustion engine being reduced from a first rate of revolution to a second rate of revolution during the change of gear, the steps of:
controlling, by an electronic control unit, the turbine and the compressor by the adjustable guide rails such that inlet pressure of the combustion gas at the inlet to the combustion chamber is reduced;
increasing, by the electronic control unit, the outlet pressure of the exhaust gas at the outlet from the combustion chamber through at least a throttle valve in the outlet, which constricts the exhaust gas flow; and
controlling, by the electronic control unit, the adjustable guide rails such that the turbine and the compressor are caused to rotate at a higher rate of revolution, which causes an increase of the inlet pressure at the inlet to the combustion chamber, when the rate of revolution of the combustion engine has at least partially fallen towards the second rate of revolution.

2. The method according to claim 1 , further comprising controlling the adjustable guide rails, by the electronic control unit, to cause the inlet pressure to increase before the rate of revolution of the combustion engine has fallen to the second rate of revolution.

3. The method according to claim 2 , further comprising starting, by the electronic control unit, the increase of the inlet pressure when the rate of revolution of the combustion engine has fallen to a rate of revolution that is constituted of the said second rate of revolution plus a selected value in the range of 10-50% of the difference in the rate of revolution between the first rate of revolution and the second rate of revolution.

4. The method according to claim 1 , further comprising starting, by the electronic control unit, the increase of the inlet pressure when the rate of revolution of the combustion engine has fallen to the second rate of revolution but before the said combustion engine is reconnected with the driving wheels through the gearbox.

5. The method according to claim 1 , further comprising, maintaining, by the electronic control unit, a constant difference in pressure between the inlet pressure and the outlet pressure during the reduction of the rate of revolution for the combustion engine.

6. The method according to claim 1 , wherein the throttle valve is arranged downstream of the outlet of the combustion chamber, whereby the outlet pressure is maintained at a constant value during the reduction in the rate of revolution, at least partially with the aid of the throttle valve, and at least until the inlet pressure has started to increase.

7. The method according to claim 1 , wherein the outlet pressure is constituted by a pressure of at least double the pressure that surrounds the vehicle.

8. The method according to claim 1 , wherein, when the inlet pressure is reduced, the electronic control unit controls the pressure at least towards a pressure lower than a pressure prevalent at the beginning of the pressure-reduction process.

9. The method according to claim 1 , further comprising, during the increase of the inlet pressure, the electronic control unit increases the outlet pressure to a pressure higher than the pressure that was prevalent at the outlet before the increase of the inlet pressure to reduce the fall in differential pressure across the combustion engine during the increase of the inlet pressure.

10. The method according to claim 9 , wherein the further increase of the outlet pressure follows the increase in the inlet pressure.

11. The method according to claim 10 , wherein, during the further increase of the outlet pressure, the electronic control unit increases the outlet pressure to a level that exceeds a limitation on pressure with respect to non-instantaneous pressure that is prevalent at the outlet.

12. The method according to claim 1 , further comprising, during the increase of the inlet pressure, controlling, by the electronic control unit, the adjustable guide rails to obtain a maximum rate of build up of the inlet pressure.

13. The method according to claim 1 , further comprising performing the method when the combustion engine is disengaged from the at least one driving wheel.

14. The method according to claim 1 , further comprising starting, by the electronic control unit, at least one of the constriction of the exhaust gas flow and the reduction of the inlet pressure at least before the combustion engine has been completely disengaged from the driving wheel.

15. The method according to claim 14 , further comprising performing the constriction of the exhaust gas flow through control, by the electronic control unit, of a constriction device arranged downstream of the turbocharger unit.

16. The method according to claim 1 , further comprising performing the constriction of the exhaust gas flow through control, by the electronic control unit, of at least one of an exhaust gas brake system and a compression brake.

17. A computer program product comprising a non-transitory medium that can be read by a computer and a computer program comprising program code stored on the medium and the stored program can be read by a computer and when the program code is executed in a computer, the computer carries out the method according to claim 1 .

18. A system for propulsion of a vehicle,
wherein the vehicle comprises:
a combustion engine, a gearbox adjustable to a plurality of gear ratios for transfer of a force between the combustion engine and at least one driving wheel, wherein the combustion engine comprises at least one combustion chamber with at least one inlet for supply of combustion gas and at least one outlet for the evacuation of an exhaust gas flow that has resulted from combustion in the combustion chamber, and a turbocharger unit configured for pressurisation of the combustion gas, the turbocharger unit comprising a turbine with adjustable guide rails and a compressor;
the system comprising:
an electronic control unit which controls the turbine and the compressor by the adjustable guide rails such that the inlet pressure of the combustion gas at the inlet to the combustion chamber is reduced during a change of gear from a first higher gear to a second lower gear ratio, a rate of revolution of the combustion engine being reduced from a first rate of revolution to a second rate of revolution during the change of gear, and
at least a throttle valve in the outlet, which increases the outlet pressure of the exhaust gas at the outlet from the combustion chamber by constriction of the exhaust gas flow during the change of gear,
wherein, when the rate of revolution of the combustion engine has at least partially fallen towards the said second rate of revolution, during the change of gear, the electronic control unit controls the adjustable guide rails such that the turbine a

Assignees

• Scania Cv Ab

Inventors

• Granström Magnus
• Larsson Anders

Classifications

• F02D41/2406

  using essentially read only memories · CPC title

• F02D2200/101

  Engine speed · CPC title

• F02B37/22

  by varying cross-section of exhaust passages or air passages {, e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits} (F02B37/24 takes precedence) · CPC title

• Y02T10/144

  Cross-Sectional Technologies · mapped topic

• F02D41/26

  using computer, e.g. microprocessor · CPC title