Apparatus and method for engine crankshaft torque ripple control in a hybrid electric vehicle

• US 6,336,070 B1
• Filed: 03/01/2000
• Issued: 01/01/2002
• Est. Priority Date: 03/01/2000
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lorenz, Robert Donald, Davis, Roy Inge
• Primary Examiner(s): Yuen, Henry C.
• Assistant Examiner(s): Vo, Hieu T.
• Application Number:
  US09/516,618
• Time in Patent Office: 671 Days
• Field of Search: 701/102, 701/110, 701/114, 701/29, 701/35, 701/99, 180/197, 123/436, 123/406.23, 731/173
• US Class Current: 701/102
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: F02D 2041/1416 Observer
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: F02D 2250/24 by using an external load, e.g. a generator
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: G01L 3/24 Devices for determining the value of power, e.g. by measuring and simultaneously multiplying the values of torque and revolutions per unit of time, by multiplying the values of tractive or propulsive force and velocity
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A control system comprising a processor develops data controlling a combustion engine and a dynamoelectric machine arranged to interact with the engine to modify the torque output of the engine. An observer (10) develops observed data that comprises estimated engine speed, estimated crankangle, and estimated engine output torque represented as an estimated average value torque component on which is superimposed an estimated alternating polarity ripple torque component whose mean value over a time interval of interest is substantially zero. The estimated alternating polarity ripple torque component is an input to a torque controller (102) for the dynamoelectric machine which causes the machine to contribute, in real time, torque that substantially cancels the alternating polarity ripple torque component in the crankshaft torque.

Claims

1. A control system for a powerplant that comprises a combustion engine including a rotating crankshaft that delivers output torque and a dynamoelectric machine arranged for interaction with the combustion engine to modify the output torque delivered by the crankshaft, the control system comprising:

a processor for developing data for controlling the combustion engine and the dynamoelectric machine, including an observer for developing observed data that comprises estimated engine output torque represented as an estimated average value torque component on which is superimposed an estimated alternating polarity ripple torque component whose mean value over a time interval of interest is substantially zero;

the observer comprising an engine model that models operation of the engine and a filter model developing the estimated alternating polarity ripple torque component from the estimated engine output torque, and a dynamoelectric machine model modeling the dynamoelectric machine;

the processor operating to process data through the engine model to develop estimated torque contribution due to engine operation;

the processor further operating to process data through the filter model to develop the estimated alternating polarity ripple torque component, to process the estimated alternating polarity ripple torque component through the dynamoelectric machine model to develop estimated dynamoelectric machine torque output, and to develop, from the estimated alternating polarity ripple torque component, dynamoelectric machine torque data representing torque that the dynamoelectric machine is commanded to deliver to substantially cancel, from output torque delivered by the crankshaft, the engine-induced ripple torque, resulting in crankshaft torque that has substantially zero mean value RMS dynamic content over a time interval of interest.

2. A control system as set forth in claim 1 in which the engine model models both positive and negative torque contributions to engine operation.

3. A control system as set forth in claim 2 in which the observer model of operation of the engine comprises both estimated engine speed and estimated crankangle.

4. A control system as set forth in claim 3 in which the observer comprises a closed loop controller that processes estimated engine speed and estimated crankangle to develop crankangle convergence.

5. A hybrid electric vehicle comprising:

a combustion engine for propelling the vehicle via a drivetrain of the vehicle and comprising a slider-crank mechanism including a rotating crankshaft that delivers output torque to a load;

a dynamoelectric machine arranged for interaction with the combustion engine to modify the output torque delivered by the crankshaft;

a control system comprising a processor for developing data controlling the combustion engine and the dynamoelectric machine, including an observer for developing observed data that comprises estimated engine speed, estimated crankangle, and estimated engine output torque represented as an estimated average value torque component on which is superimposed an estimated alternating polarity ripple torque component whose mean value over a time interval of interest is substantially zero;

the observer comprising a combustion process model developing modeled pressure estimates of combustion chamber pressures in engine cylinders according to data that influences combustion chamber pressures, a kinematics model relating reciprocal motion of pistons in the engine cylinders to engine crankshaft rotation, an engine friction model relating running friction of the engine to engine crankshaft rotation, an observer closed loop controller to force convergence of estimated crankangle to measured crankangle, a filter model developing the estimated alternating polarity ripple torque component from the estimated engine output torque, a dynamoelectric machine model modeling the dynamoelectric machine, an engine load model modeling load on the engine crankshaft, and a moment of inertia model modeling moment of inertia of the slider-crank mechanism of the engine as a function of crankangle;

the processor operating to process data through the combustion process model to develop the modeled pressure estimates, to process estimated crankangle and the modeled pressure estimates through the kinematics model to develop estimated positive torque contribution due to combustion processes, to process the modeled pressure estimates, the estimated crankangle, and the estimated engine speed through the engine friction model to develop estimated torque loss due to engine running friction, and to process the estimated positive torque contribution due to combustion processes and the estimated torque loss due to engine running friction to develop the estimated engine torque output;

the processor further operating to process the measured crankangle and the estimated crankangle through the observer closed loop controller to develop crankangle convergence data, to process the estimated engine torque output and the crankangle convergence data through the filter model to develop the estimated alternating polarity ripple torque component, and to process the estimated alternating polarity ripple torque component through the dynamoelectric machine model to develop estimated dynamoelectric machine torque output, to subtract the estimated dynamoelectric machine torque output from the estimated engine torque output and process that difference and the convergence data through the moment of inertia model to develop the estimated crankangle and the estimated engine speed;

and the processor further operating to process the estimated crankangle, the estimated engine speed, and the estimated alternating polarity ripple torque component to develop dynamoelectric machine torque data representing torque that the dynamoelectric machine is commanded to deliver to substantially cancel, from output torque delivered by the crankshaft, the engine-induced ripple torque, resulting in crankshaft torque that has substantially zero mean value RMS dynamic content over a time interval of interest.

6. A control system for a powerplant that comprises a combustion engine having a slider-crank mechanism including a rotating crankshaft that delivers output torque and a dynamoelectric machine arranged for interaction with the combustion engine to modify the output torque delivered by the crankshaft, the control system comprising:

a processor for developing data for controlling the combustion engine and the dynamoelectric machine, including an observer for developing observed data that comprises estimated engine speed, estimated crankangle, and estimated engine output torque represented as an estimated average value torque component on which is superimposed an estimated alternating polarity ripple torque component whose mean value over a time interval of interest is substantially zero;

the observer comprising a combustion process model developing modeled pressure estimates of combustion chamber pressures in engine cylinders according to data that influences combustion chamber pressures, a kinematics model relating reciprocal motion of pistons in the engine cylinders to engine crankshaft rotation, an engine friction model relating running friction of the engine to engine crankshaft rotation, an observer closed loop controller to force convergence of estimated crankangle to measured crankangle, a filter model developing the estimated alternating polarity ripple torque component from the estimated engine output torque, a dynamoelectric machine model modeling the dynamoelectric machine, an engine load model modeling load on the engine crankshaft, and a moment of inertia model modeling moment of inertia of the slider-crank mechanism of the engine as a function of crankangle;

the processor operating to process data through the combustion process model to develop the modeled pressure estimates, to process estimated crankangle and the modeled pressure estimates through the kinematics model to develop estimated positive torque contribution due to combustion processes, to process the modeled pressure estimates, the estimated crankangle, and the estimated engine speed through the engine friction model to develop estimated torque loss due to engine running friction, and to process the estimated positive torque contribution due to combustion processes and the estimated torque loss due to engine running friction to develop the estimated engine torque output;

the processor further operating to process the measured crankangle and the estimated crankangle through the observer closed loop controller to develop crankangle convergence data, to process the estimated engine torque output and the crankangle convergence data through the filter model to develop the estimated alternating polarity ripple torque component, and to process the estimated alternating polarity ripple torque component through the dynamoelectric machine model to develop estimated dynamoelectric machine torque output, to subtract the estimated dynamoelectric machine torque output from the estimated engine torque output and process that difference and the convergence data through the moment of inertia model to develop the estimated crankangle and the estimated engine speed;

and the processor further operating to process the estimated crankangle, the estimated engine speed, and the estimated alternating polarity ripple torque component to develop dynamoelectric machine torque data representing torque that the dynamoelectric machine is commanded to deliver to substantially cancel, from output torque delivered by the crankshaft, the engine-induced ripple torque, resulting in crankshaft torque that has substantially zero mean value RMS dynamic content over a time interval of interest.

7. A method of controlling a dynamoelectric machine to substantially cancel substantially zero mean value ripple torque induced in a crankshaft of a combustion engine by combustion events that are effective on the crankshaft through a slider-crank mechanism, the method comprising:

processing data through an observer to develop observed data that comprises estimated engine speed, estimated crankangle, and estimated engine output torque represented as an estimated average value torque component on which is superimposed an estimated alternating polarity ripple torque component whose mean value over a time interval of interest is substantially zero;

processing data through a combustion process model in the observer to develop modeled pressure estimates of combustion chamber pressures in engine cylinders according to data that influences combustion chamber pressures;

processing estimated crankangle and the modeled pressure estimates through a kinematics model in the observer relating reciprocal motion of pistons in the engine cylinders to engine crankshaft rotation to develop estimated positive torque contribution due to combustion processes;

processing the modeled pressure estimates, the estimated crankangle, and estimated engine speed through an engine friction model in the observer relating running friction of the engine to engine crankshaft rotation to develop estimated torque loss due to engine running friction;

processing, in the observer, the estimated positive torque contribution due to combustion processes and the estimated torque loss due to engine running friction to develop estimated engine torque output;

processing the measured crankangle and the estimated crankangle through an observer closed loop controller to force convergence of estimated crankangle to measured crankangle to develop crankangle convergence data;

processing the estimated engine torque output and the crankangle convergence data through a filter model in the observer for developing the estimated alternating polarity ripple torque component to develop the estimated alternating polarity ripple torque component from the estimated engine output torque;

processing the estimated alternating polarity ripple torque component through a dynamoelectric machine model in the observer modeling the dynamoelectric machine to develop estimated dynamoelectric machine torque output;

subtracting the estimated dynamoelectric machine torque output from the estimated engine torque output and processing that difference and the convergence data through an engine load model in the observer modeling load on the engine crankshaft and a moment of inertia model in the observer modeling moment of inertia of the slider-crank mechanism as a function of crankangle to develop the estimated crankangle and the estimated engine speed; and

processing the estimated crankangle, the estimated engine speed, and the estimated alternating polarity ripple torque component to develop dynamoelectric machine torque data representing torque that the dynamoelectric machine is commanded to deliver to substantially cancel, from output torque delivered by the crankshaft, the engine-induced ripple torque, resulting in crankshaft torque that has substantially zero mean value RMS dynamic content over a time interval of interest.