Method for shutting down and restarting individual cylinders of an engine

• US 5,803,040 A
• Filed: 12/13/1996
• Issued: 09/08/1998
• Est. Priority Date: 12/13/1995
• Status: Expired due to Fees

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Klein, Peter, Flebbe, Heiko, Waltner, Anton, Biesinger, Herwig, Kalweit, Dieter, Lautenschutz, Peter
• Primary Examiner(s): Kamen, Noah P.
• Application Number:
  US08/764,390
• Time in Patent Office: 634 Days
• Field of Search: 123/198 F, 123/481, 123/90.15
• US Class Current: 123/198.00F
• CPC Class Codes: F01L 13/0036 the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

The invention provides a method for shutting down and restarting individual cylinders of a multicylinder internal combustion engine by deactivating the charge change valves and the fuel injection. According to the invention, in shutting down a selected cylinder, the exhaust valve is disconnected first in all cases. Thereafter, the intake valve and fuel injection for the selected cylinder are controlled such that the last fuel injection into that cylinder takes place immediately before the last intake cycle. When a cylinder is restarted, the exhaust valve is always operated first, and only thereafter is the intake valve opened, with the first fuel injection always taking place immediately before the first intake cycle.

Claims

1. Method for shutting down and starting individual cylinders of a multicylinder internal combustion engine having at least one intake valve and at least one exhaust valve per cylinder, and a device for fuel injection for individual cylinders, with said valves of a selected individual cylinder being deactivated or activated during a shutdown or restart of said selected cylinder by means of a shutdown device, and the fuel injection in said selected cylinder being deactivated or activated as a function of an operating state of said valves, the improvement comprising:

when said selected cylinder is switched, a time sequence for activation or deactivation of intake and exhaust valves is controlled such that a shutdown of said selected cylinder takes place after one intake cycle and prior to a next succeeding exhaust cycle thereof, and a restart of said selected cylinder takes place before one exhaust cycle and after a next preceding intake cycle thereof;

a crankshaft angle is preset for said shutdown device relative to a reference mark on a crankshaft or camshaft of said engine on which the switching process is to begin;

an angular switching position of said disconnection device is determined as a function of operating parameters;

when a switching signal is present, the angular switching position and the crankshaft angle are added to a current crankshaft angle;

a next succeeding reference mark is determined on the basis of said crankshaft angle, and angular switching position for the disconnection device is calculated by substracting the crankshaft angle and angular switching position; and

when an angular switching position is reached, said disconnection device is activated.

2. Method according to claim 1, wherein:

intake and exhaust valves of at least one cylinder of the multicylinder internal combustion engine each have a coupling device that can be switched only outside preset valve lift curves, and are actuated by a common disconnection device; and

when a switching signal is present, said disconnection device is activated at a point in time at which all intake valves to be switched have at least begun a respective intake cycle of a previous operating cycle relative to a first cylinder to be switched, ensuring that a coupling process at an exhaust value of the first cylinder to be switched is completed before an exhaust cycle of said first cylinder begins.

3. Method according to claim 1, wherein fuel injection of said selected cylinder is deactivated or activated as a function of a state of cylinder shutdown.

4. Method for shutting down and starting individual cylinders of a multicylinder internal combustion engine having at least one intake valve and at least one exhaust valve per cylinder, and a device for fuel injection for individual cylinders, with said valves of a selected individual cylinder being deactivated or activated during a shutdown or restart of said selected cylinder by means of a shutdown device, and the fuel injection in said selected cylinder being deactivated or activated as a function of an operating state of said valves, the improvement comprising:

when said selected cylinder is switched, a time sequence for activation or deactivation of intake and exhaust valves is controlled such that a shutdown of said selected cylinder takes place after one intake cycle and prior to a next succeeding exhaust cycle thereof, and a restart of said selected cylinder takes place before one exhaust cycle and after a next preceding intake cycle thereof;

intake and exhaust valves of a plurality of cylinders of the multicylinder internal combustion engine each have a coupling device that is switchable only outside preset valve lift curves, and are actuated by a common disconnection device; and

when a switching signal is present disconnection devices are activated at a point in time at which all intake and exhaust valves to be switched have at least begun a respective intake or exhaust cycle of a previous operating cycle relative to a first cylinder to be switched, ensuring that a coupling process at an intake or exhaust valve of the first cylinder to be switched is complete before an intake or exhaust cycle of said first cylinder begins.