Method for cylinder cut-in in an internal combustion engine process

• US 5,727,527 A
• Filed: 04/19/1996
• Issued: 03/17/1998
• Est. Priority Date: 04/19/1995
• Status: Expired due to Fees

• Current Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: Dr ING HCF Porsche AG
• Inventors: Mueller, Stephan, Schwarzenthal, Dietmar
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US08/635,139
• Time in Patent Office: 697 Days
• Field of Search: 123/198 F, 123/481, 123/681, 123/682
• US Class Current: 123/481
• CPC Class Codes: F02B 2075/1824 six
• CPC Class Codes: F02B 75/22 with cylinders in V, fan, or star arrangement
• 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

A method for cylinder cut-in in an internal combustion engine, with the engine having on a portion of its cylinders. The charge changing valves can be cut out as well as a switchable fuel supply, both of which can be switched from a cut-out or cut-off state to a cut-in state and vice versa. In order to provide a method for cylinder cut-in that permits a safe transition from operation in which they are cut out to one in which they are not cut out, and by which the effects of this switch are exhaust behavior are minimized, the charge changing valves are cut in first and then, after checking to determine whether the charge changing valves have been switched, the fuel supply is cut in to the cylinders that were previously cut out.

Claims

1. A method for cylinder cut-in in an internal combustion engine having a plurality of cylinders, at least one of the cylinders having switchable charge changing valves and a switchable fuel supply, the switchable charge changing valves and the switchable fuel supply being switchable between a cutout state and a cut-in state, the internal combustion engine being connected to a regulated catalytic converter and a lambda probe being used for control, said method comprising the steps of:

cutting in the charge changing valves,

determining whether the charge changing valves have been switched to the cut-in state, and

cutting in the fuel supply to the cylinders,

replacing a lambda probe signal by a replacement signal at least during the steps of cutting in the charge changing valves, determining whether the charge changing valves have been switched, and cutting in the fuel supply to the cylinders, and

selecting the replacement signal so that an air ratio between exhaust from the cylinders which are in the cut-in state and exhaust from the cylinders which are in the cut out state is essentially equal to 1.

2. A method according to claim 1, wherein the charge changing valves are switched by hydraulic pressure, and wherein the charge changing valves are cut in according to the following steps:

cutting in the hydraulic pressure,

waiting for a predetermined time which is normally required until the hydraulic pressure has built up,

determining whether the hydraulic pressure has reached a minimum threshold value, and

interrupting the cylinder cut-in if the hydraulic pressure is below the minimum threshold value.

3. A method according to claim 1, wherein the charge changing valves are cut in according to the following steps:

initiating cut-in of the charge changing valves,

determining whether the charge changing valves have been cut in,

interrupting the cylinder cut-in if the charge changing valves have not been cut-in.

4. A method according to claim 1, wherein the charge changing valves are cut in according to the following steps:

initiating cut-in of the charge changing valves,

determining whether the charge changing valves have been cut in,

interrupting the cylinder cut-in if the charge changing valves have not been cut-in;

wherein the step of determining whether the charge changing valves have been cut in comprises the following steps;

determining a time window valid for a camshaft contour currently selected and a corresponding closing pulse threshold value for a closing pulse of the charge changing valves,

waiting for said time window,

determining a detonation signal delivered by a detonation sensor, and

comparing the detonation signal with the closing pulse threshold value;

determining that the charge changing valves have been cut in if the threshold value has been reached, and

determining that the charge changing valves have not been cut in if the threshold value has not been reached.

5. A method for cylinder cut-in in an internal combustion engine having a plurality of cylinders, at least one of the cylinders having switchable charge changing valves and a switchable fuel supply, the switchable charge changing valves and the switchable fuel supply being switchable between a cutout state and a cut-in state, the charge changing valves being switched by hydraulic pressure, wherein the method comprises the steps of:

cutting in the charge changing valves,

determining whether the charge changing valves have been switched to the cut-in state, and

cutting in the fuel supply to the cylinders;

and wherein the charge changing valves are cut in according to the following steps;

cutting in the hydraulic pressure,

waiting for a predetermined time which is normally required until the hydraulic pressure has built up,

determining whether the hydraulic pressure has reached a minimum threshold value, and

interrupting the cylinder cut-in if the hydraulic pressure is below the minimum threshold value.

6. A method for cylinder cut-in in an internal combustion engine having a plurality of cylinders, at least one of the cylinders having switchable charge changing valves and a switchable fuel supply, the switchable charge changing valves and the switchable fuel supply being switchable between a cutout state and a cut-in state, wherein the method comprises the steps of:

cutting in the charge changing valves,

determining whether the charge changing valves have been switched to the cut-in state, and

cutting in the fuel supply to the cylinders;

wherein the charge changing valves are cut in according to the following steps;

initiating cut-in of the charge changing valves,

determining whether the charge changing valves have been cut in,

interrupting the cylinder cut-in if the charge changing valves have not been cut in;

wherein the step of determining whether the charge changing valves have been cut in comprises the following steps;

determining a time window valid for a camshaft contour currently selected and a corresponding closing pulse threshold value for a closing pulse of the charge changing valves,

waiting for said time window,

determining a detonation signal delivered by a detonation sensor, and

comparing the detonation signal with the closing pulse threshold value;

determining that the charge changing valves have been cut in if the threshold value has been reached, and

determining that the charge changing valves have not been cut in if the threshold value has not been reached.

7. A method for cylinder cut-in in an internal combustion engine having a plurality of cylinders, at least one of the cylinders having switchable charge changing valves and a switchable fuel supply, the switchable charge changing valves and the switchable fuel supply being switchable between a cutout state and a cut-in state, wherein the method comprises the steps of:

cutting in the charge changing valves,

determining whether the charge changing valves have been switched to the cut-in state, and

cutting in the fuel supply to the cylinders;

wherein fuel is supplied during cylinder cut-in in such fashion that an essentially stoichiometric exhaust composition is produced, while discontinuities that occur in the output torque are converted into a smooth transition by changing an ignition angle.