Safety system for an automatic gearbox
First Claim
1. A method for detecting an error for an automatic transmission, the automatic transmission comprising a hydrodynamic converter (3), a plurality of couplings and brakes (A to F), a hydraulic control instrument (21), and an electronic control instrument (13), the electronic control instrument (13), in accordance with input values (18 to 20), and controlling said plurality of couplings and brakes via the hydraulic control instrument (21), wherein a transmission ratio (i) is switched by a suitable coupling-brake combination, said method comprising the steps of:
- monitoring, with the electronic control instrument (13) and with the aid of the curves of the transmission input speed (nT(t)) and of the transmission output speed (nAB(t)), a current gear (GUEW=nT(t)-nAB(t)xi);
interpreting a fault in the gear monitoring, which has been present for more than a presettable period of time, as an error; and
switching from the current gear (G) to a replacement gear (G'"'"') when the error appears, wherein the replacement gear corresponds to a next higher gear (G'"'"'=G+1), when the current gear (G) was one of first gear (G1), second gear (G2), third gear (G3), and fourth gear (G4) and corresponds to a next lower gear (G'"'"'=G-1) when the current gear was fifth gear (G5).
1 Assignment
0 Petitions
Accused Products
Abstract
In an automatic transmission in which the electronic control instrument (13) detects, outside the circuits, a fault in the input values (18 to 20), the couplings and the brakes (A to F). When a fault is present for an extended period, the electronic control instrument (13) detects a symptom and switches to a replacement gear. Hereby maximum driveability is ensured without a diagnosis entry.
-
Citations
6 Claims
-
1. A method for detecting an error for an automatic transmission, the automatic transmission comprising a hydrodynamic converter (3), a plurality of couplings and brakes (A to F), a hydraulic control instrument (21), and an electronic control instrument (13), the electronic control instrument (13), in accordance with input values (18 to 20), and controlling said plurality of couplings and brakes via the hydraulic control instrument (21), wherein a transmission ratio (i) is switched by a suitable coupling-brake combination, said method comprising the steps of:
-
monitoring, with the electronic control instrument (13) and with the aid of the curves of the transmission input speed (nT(t)) and of the transmission output speed (nAB(t)), a current gear (GUEW=nT(t)-nAB(t)xi); interpreting a fault in the gear monitoring, which has been present for more than a presettable period of time, as an error; and switching from the current gear (G) to a replacement gear (G'"'"') when the error appears, wherein the replacement gear corresponds to a next higher gear (G'"'"'=G+1), when the current gear (G) was one of first gear (G1), second gear (G2), third gear (G3), and fourth gear (G4) and corresponds to a next lower gear (G'"'"'=G-1) when the current gear was fifth gear (G5). - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification