US 5,568,387 A · Method and arrangement for adaptive switching off of the exhaust brake in connection with upshift

Abstract

The invention relates to an improved method and an arrangement for implementation of that method for obtaining safer and quicker upshifts while maintaining gear change comfort, using computer-assisted systems for gear change in mechanical gearboxes in motor vehicles, preferably without clutch disengagement between engine and gearbox. In connection with upshift, an exhaust brake is activated, (EB.sub.on) at time t.sub.1 in parallel with the fuel (FUEL) to the engine being reduced to zero quantity. The engine speed n.sub.2 is thereby reduced more quickly to the speed n.sub.1 which is the synchronous engine speed for the next higher gear. The speed reduction is monitored with a view to achieving rapid engine speed bracketing to synchronous speed, and also good gear change smoothness and safe gear engagement. The exhaust brake switch-off point EB.sub.off at time t.sub.2 is adjusted adaptively for subsequent upshift by a connection factor EBA.sub.off so that the engine speed falls to a level Maxdip within a predetermined speed range below the synchronous engine speed, preferably between 15 and 50 rpm below the synchronous speed.

Claims12

Dependent claims

A computer assisted method for controlling an upshift from a lower gear to a higher gear in a motor vehicle having an exhaust brake which is activated to lower an engine speed to a speed which is synchronized with the higher gear, which method comprises the steps of:

a) shifting from a lower gear to a higher gear;
b) activating the exhaust brake during step (a);
c) deactivating the exhaust brake during step (a) at a predetermined time after step (b);
d) determining the engine speed after step (c);
e) comparing the engine speed determined in step (d) with the synchronized speed required for the higher gear;
f) determining in accordance with predetermined criteria whether the predetermined time for deactivation of the exhaust brake for the next shift to a higher gear should be changed;
and
g) if step (f) indicates that the predetermined time should be changed, changing the predetermined time so that during the next shift to a higher gear the exhaust brake is deactivated at a new predetermined time.

5 more elements

Dependencies are inferred from the claim text.

Method and arrangement for adaptive switching off of the exhaust brake in connection with upshift

Life of this patent

Method and arrangement for adaptive switching off of the exhaust brake in connection with upshift

Life of this patent

Abstract

Claims12