System and method to control a switchable powertrain mount

Abstract

A strategy controls alternate anti-vibration modes in a switchable powertrain mount using vehicle operational status sensors and pre-selected thresholds. The switchable mount modes can include engine idle and a default engine off/run. Vehicle sensors and pre-selected thresholds can determine whether the engine is off, idle, or running and when in idle mode, whether the engine will likely remain in idle mode. From these determinations, the controller can command the switchable mount to engine idle mode when the controller determines the engine is in idle mode and will likely remain in idle mode. The switching means for the switchable mount can use a three-way vacuum solenoid valve (VSV), or a mechanical or electrical switch. In the case of the VSV configuration, the VSV is communicatively attached to the controller, a vacuum line connects the VSV to the switchable mount, and a second vacuum line connects the VSV to an engine intake manifold.

1 . A mount assembly for coupling a vehicle powertrain assembly and a vehicle chassis, the mount assembly comprising: 
 at least one switchable mount operable in at least an engine idle mode;    at least one vehicle sensor operatively connected to the powertrain; and    a controller for receiving and processing input from the at least one vehicle sensor, and    for commanding the switchable mount to be in the engine idle mode when the processed input of at least one vehicle sensor exceeds a pre-selected threshold.    
     
     
         2 . The mount assembly of  claim 1 , wherein the switchable mount is adapted to be attached to an engine of the vehicle powertrain assembly.  
     
     
         3 . The mount assembly of  claim 1 , wherein the controller controls the actuation of a three-way vacuum solenoid valve (VSV) communicatively attached to the controller and wherein the mount assembly further comprises, 
 a first vacuum line for connecting the VSV to the switchable mount, and    a second vacuum line for connecting the VSV to an engine intake manifold.    
     
     
         4 . The mount assembly of  claim 1 , wherein the controller controls the actuation of a mechanical switch.  
     
     
         5 . The mount assembly of  claim 1 , wherein the controller controls the actuation of an electrical switch.  
     
     
         6 . The mount assembly of  claim 1  wherein the at least one vehicle sensor is adapted to measure one or more of engine speed, accelerator position, key ON/OFF position, and gear selector position.  
     
     
         7 . The mount assembly of  claim 1  wherein the pre-selected threshold comprises a measured increase in engine torque rate.  
     
     
         8 . The mount assembly of  claim 1  wherein the pre-selected threshold comprises a minimum measured increase in engine speed rate.  
     
     
         9 . The mount assembly of  claim 8 , wherein the increase in engine speed rate is at least 4000 RPM/sec.  
     
     
         10 . The mount assembly of  claim 1  wherein the controller comprises a delay timer for delaying the issuance of a command signal for a pre-selected time interval.  
     
     
         11 . The mount assembly of  claim 10 , wherein the time interval is between 500 and 1000 milliseconds.  
     
     
         12 . The mount assembly of  claim 6 , wherein the at least one vehicle sensor measures a powertrain crankshaft speed.  
     
     
         13 . The mount assembly of  claim 6 , wherein the at least one vehicle sensor measures a powertrain camshaft speed.  
     
     
         14 . A vehicle, comprising: 
 a powertrain having an engine and a vehicle chassis and being provided with a mount assembly for coupling the vehicle powertrain assembly and said vehicle chassis; and    the mount assembly comprising, at least one switchable mount operable in at least an engine idle mode, at least one vehicle sensor operatively connected to the powertrain, and a controller for receiving and processing input from the at least one vehicle sensor, and    for commanding the switchable mount to be in the engine idle mode when the processed input of at least one vehicle sensor exceeds a pre-selected threshold.    
     
     
         15 . The vehicle of  claim 14 , wherein said vehicle is a hybrid electric vehicle.  
     
     
         16 . A method for controlling a switchable mount assembly that couples a vehicle powertrain assembly and a vehicle chassis comprising the steps of: 
 receiving and processing input of at least one vehicle sensor output; and    commanding the switchable mount to switch from a default drive mode to an engine idle mode when the processed input of at least one vehicle sensor exceeds a pre-selected threshold.    
     
     
         17 . The method of  claim 16 , wherein the step of receiving input of at least one vehicle sensor comprises at least one of the steps of: 
 receiving an output of an engine speed sensor;    receiving an output of an accelerator position sensor;    receiving an output of an key ON/OFF sensor; and    receiving an output of a gear selector position sensor.    
     
     
         18 . The method of  claim 16 , wherein the step of commanding the switchable mount to switch from said default drive mode to said engine idle mode comprises the steps of: 
 determining whether a pre-selected threshold increase in engine torque rate is exceeded;    determining whether a pre-selected threshold increase in engine speed rate is exceeded; and    determining whether a pre-selected time interval has been exceeded.    
     
     
         19 . A system for controlling a switchable mount assembly adapted for coupling a vehicle powertrain assembly and a vehicle chassis, comprising: 
 at least one sensor provided within the powertrain assembly for issuing an output signal;    a controller operatively connected to the at least one sensor;    a program of control logic embodied within the controller to interpret said signal and to issue a command signal based on said interpretation to control the switchable mount to alternate between at least two operational modes thereby providing at least two alternate vibration damping support characteristics between said powertrain and said vehicle chassis.    
     
     
         20 . The system of  claim 19 , wherein the control logic is adapted to determine if said engine is in an idle mode and likely to remain in said idle mode.