Monitoring of transmission-to-engine speed requests
View Patent ↗A vehicle includes an engine having a crankshaft which rotates at an engine speed, a transmission having a rotatable input member, a transmission control module (TC), and an engine control module (ECM) in communication with the TCM. The TCM is programmed to execute a transmission-to-engine speed monitoring and control method which includes transmitting an engine speed request to the ECM which requests a positive increase in the engine speed, and terminating the request when the request is active for more than a first calibrated timeout duration. The TCM also terminates the request when the request is active for more than a second calibrated duration that is less than the first calibrated duration, the transmission is not in neutral, and both a shift of the transmission and an acceleration of the input member are not active.
1. A vehicle comprising:
an engine having a crankshaft which rotates at an engine speed;
a transmission having a rotatable input member;
a transmission control module (TCM); and
an engine control module (ECM) in communication with the TCM;
wherein the TCM is programmed to transmit an engine speed request to the ECM which requests a positive increase in the engine speed in anticipation of a predetermined shift event of the transmission, and to automatically terminate the engine speed request when the positive engine speed request is active for more than a first calibrated timeout duration when the transmission is not in neutral and both a shift of the transmission and an acceleration of the input member are not active, and after a second timeout duration that exceeds the first calibrated timeout duration regardless of whether the transmission is in neutral and the shift of the transmission and the acceleration of the input member are active.
2. The vehicle of claim 1 , wherein the TCM is programmed to calculate a neutral speed ratio of the transmission, and to compare the calculated neutral speed ratio to a calibrated ratio to determine whether the transmission is not in neutral.
3. The vehicle of claim 1 , wherein the second calibrated timeout duration is about 800 ms to 900 ms.
4. The vehicle of claim 1 , wherein the first calibrated timeout duration is about 150 ms to 250 ms.
5. The vehicle of claim 1 , wherein the transmission is an automatic transmission.
6. The vehicle of claim 1 , wherein the predetermined shift event is a downshift.
7. A transmission assembly for use in a vehicle having an engine control module (ECM) and an engine, wherein the engine includes a crankshaft which rotates at an engine speed, the transmission assembly comprising:
a transmission having a rotatable shaft; and
a transmission control module (TCM) in communication with the ECM;
wherein the TCM is programmed to transmit an engine speed request to the ECM which requests a positive increase in the engine speed in anticipation of a predetermined shift event of the transmission, and to automatically terminate the engine speed request when the positive engine speed request is active for more than a first calibrated timeout duration when the transmission is not in neutral and both a shift of the transmission and an acceleration of the input member are not active, and after a second timeout duration that exceeds the first calibrated timeout duration regardless of whether the transmission is in neutral and the shift of the transmission and the acceleration of the input member are active.
8. The transmission assembly of claim 7 , wherein the TCM is programmed to calculate a neutral speed ratio of the transmission, and to compare the calculated neutral speed ratio to a calibrated ratio to determine whether the transmission is not in neutral.
9. The transmission assembly of claim 7 , wherein the first calibrated timeout duration is about 150 ms to 250 ms.
10. The transmission assembly of claim 7 , wherein the second calibrated timeout duration is about 800 ms to 900 ms.
11. The transmission assembly of claim 7 , wherein the transmission is an automatic transmission.
12. The transmission assembly of claim 7 , wherein the predetermined shift event is a downshift.
13. A method for use in a vehicle having a transmission with an input member, a transmission control module (TCM), an engine, and an engine control module (ECM), wherein the engine includes a crankshaft which rotates at an engine speed, the method comprising:
transmitting a positive engine speed request from the TCM to the ECM, wherein the engine speed request is a request for an increase in the engine speed in anticipation of a predetermined shift of the transmission;
determining whether the positive engine speed request is active for more than a first calibrated timeout duration;
automatically terminating the positive engine speed request when the positive engine speed request is active for more than a first calibrated timeout duration during which the transmission is not in neutral and both a shift of the transmission and an acceleration of the input member are not active, and after a second timeout duration that exceeds the first calibrated timeout duration regardless of whether the transmission is in neutral and the shift of the transmission and the acceleration of the input member are active.
14. The method of claim 13 , further comprising determining whether the transmission is not in neutral by calculating a neutral speed ratio of the transmission, and comparing the calculated neutral speed ratio to a calibrated ratio.
15. The method of claim 13 , wherein the first calibrated timeout duration is about 150 ms to 250 ms.
16. The method of claim 13 , wherein the second calibrated timeout duration is about 800 ms to 900 ms.