US 2003/0115014 A1Published application

Method and apparatus for automatically setting rocker arm clearances in an internal combustion engine

AssigneePerkins Engines Company Limited

InventorsGraham P. Batchelor, William M. Crozier

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Abstract

A method for automatically setting valve clearances in internal combustion engines (also known as “tappet setting” or “valve lash setting”) comprises a series of steps in which a rocker arm is set to a zero position that is recorded as a reference datum and an adjustment screw is then operated to set the rocker arm to a first reference position. The adjustment screw is then rotated through a predetermined angle so that the rocker arm is moved to a second reference position. The difference between the first and second reference positions and the predetermined angle are used to determine a coefficient relating the angular movement of the adjustment screw to linear movement of the rocker arm. The coefficient is then used to calculate the angular rotation of the adjustment screw required to set a predetermined valve clearance relative to the zero position. The initial adjustment of the rocker arm position serves to neutralize backlash in the valve drive train prior to setting the valve clearance. The method and associated apparatus may also be used to set the clearance between a rocker arm and other rocker arm actuated engine components.

Claims16

Dependent claims

A method of setting a predetermined clearance in an internal combustion engine between a rocker arm and a rocker arm actuated engine component, in which a rocker arm is rotatably mounted on a rocker shaft for reciprocating movement relative thereto, the rocker arm having a first end located on a first side of the rocker shaft and a second end located on a second side of the rocker shaft, the first end of the rocker arm having an adjustment screw extending therethrough to act on an end of a push rod, the second end of the rocker arm being movable in a first, component-actuating, direction and in a second direction opposite to said first direction and having a component engaging surface co-operating with a portion of the rocker arm actuated engine component, at least a portion of the rocker arm actuated engine component being biased in said second direction towards a first position and being movable against the bias in said first direction towards a second position, the method comprising the steps of:

(a) setting the rocker arm to a zero position and recording said zero position as a reference datum;
(b) rotating the adjustment screw to adjust the position of said rocker arm to a first reference position;
(c) rotating the adjustment screw through a reference angle and recording a corresponding second reference position thereof;
(d) calculating a coefficient from the difference between said first and second reference positions and said reference angle;
(e) using said coefficient to calculate an angular rotation of the adjustment screw corresponding to said predetermined clearance;
and
(f) rotating the adjustment screw on the basis of said calculated angular rotation to set the predetermined clearance relative to said reference datum.

4 more elements

An apparatus for setting a predetermined clearance in an internal combustion engine between a rocker arm and a rocker arm actuated engine component, in which a rocker arm is rotatably mounted on a rocker shaft for reciprocating movement relative thereto, the rocker arm having a first end located on a first side of the rocker shaft and a second end located on a second side of the rocker shaft, the first end of the rocker arm having an adjustment screw extending therethrough to act on an end of a push rod, the second end of the rocker arm being movable in a first, component-actuating, direction and in a second direction opposite to said first direction and having a component engaging surface co-operating with a portion of the rocker arm actuated engine component, at least a portion of the rocker arm actuated engine component being biased in said second direction towards a first position and being movable against the bias in said first direction towards a second position, the apparatus comprising:

an electronic controller;
a rocker arm actuator responsive to said electronic controller to selectively rotate the rocker arm relative to the rocker shaft;
a rocker arm position sensor operably connected with said electronic controller to record with said electronic controller the position of the second end of said rocker arm;
and
an adjustment screw rotator responsive to said electronic controller to selectively rotate the rocker arm adjustment screw;
wherein said electronic controller is programmed to (a) a cause said rocker arm actuator to set the rocker arm to a zero position and record said zero position as a reference datum, (b) cause the adjustment screw rotator to rotate the adjustment screw to adjust the position of said rocker arm to a first reference position and then rotate the adjustment screw through a reference angle, (c) record a corresponding second reference position of the rocker arm, (d) calculate a coefficient from the difference between said first and second reference positions and said reference angle, (e) use said coefficient to calculate an angular rotation of the adjustment screw corresponding to said predetermined clearance, and (f) cause said adjustment screw rotator to rotate the adjustment screw on the basis of said calculated angular rotation to set the predetermined clearance relative to said reference datum.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/348,799Filed 21 Jan 2003
Priority: GB 0021181.330 Aug 2000
Published: 19 Jun 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

F01L 1/20
Valve-gear or valve arrangements, e.g. lift-valve gear: adjusting or compensating clearance
F01L 1/181
Rocking arms or levers: centre pivot rocking arms
F01L 2303/01
Manufacturing of components used in valve arrangements: tools for producing, mounting or adjusting, e.g. some part of the distribution
F01L 2800/09
Methods of operation using a variable valve timing mechanism: calibrating

Family

Application09/943,615Continuation · filed 30 Aug 2001
Application10/348,799Continuation · filed 21 Jan 2003
US 2002/0077762 A1Published application
US 6,546,347 B2Related patent
US 6,675,115 B2Related patent
US 2003/0115014 A1This patent

From the US filing history. Foreign family members aren’t listed.