Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
2000-05-30
2001-11-06
Wolfe, Willis R. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C123S480000, C123S492000, C073S117020
Reexamination Certificate
active
06314359
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to systems for controlling engine operation toward an optimum operating point, and more particularly to such systems operable to modify such control during vehicle acceleration and deceleration conditions.
BACKGROUND OF THE INVENTION
It is known in the control of internal combustion engines, particularly in industrial applications, to control engine load via an external generator. Such generators are typically electronically controlled and are responsive to at least a so-called “load bias” signal produced by electronic engine control circuitry to apply a corresponding load to the engine.
An example of a portion of a prior art control circuit
3
producing a steady state load bias signal (LB) is shown in FIG.
1
. Control circuit
3
includes a load bias calculation block
5
receiving a commanded fueling (CF) signal and an engine speed (ES) signal, wherein block
5
is operable to produce the load bias signal LB as a function thereof. Conventionally, the load bias signal is determined by comparing ES with CF and producing LB as a signal proportional to where the current engine operation point is (typically in relation to an engine output power or torque curve or map) relative to an optimal operating point. The optimal rating point is typically determined as the most efficient engine power generated at a given engine speed.
While the prior art load bias signal LB provides for accurate and effective engine load control during steady state operating conditions, this accuracy and efficacy diminishes during transient operating conditions. For example, during engine acceleration conditions, if the load bias signal LB is directly followed it results in less than optimal or sluggish engine performance. Optimal engine acceleration is dependent on the amount of air (boost pressure) and fuel available to the engine at any given engine speed.
Likewise, during deceleration of the engine, if the load bias curve is directly followed it results in less than optimal engine performance. The load bias signal in this case will request more load as the engine is decelerating, as the requested fueling is very low during deceleration conditions (i.e. the operator lets up on the throttle). The engine accordingly decelerates at the same time that the load bias signal is requesting more loading, which results in excessive loading on the engine when the target engine RPM is reached. This typically results in the target RPM being overshot, which is an undesirable engine response.
What is therefore needed is a system for improving the load bias signal LB to provide optimal engine performance not only during steady state engine operating conditions, but also during transient engine operating conditions such as during engine acceleration and deceleration.
SUMMARY OF THE INVENTION
The foregoing shortcomings of the prior art are addressed by the present invention. In accordance with one aspect of the present invention, a system for producing an adjusted load bias signal to provide for optimal acceleration conditions for an internal combustion engine comprises means for sensing engine rotational speed and producing an engine speed signal corresponding thereto, means for sensing intake air pressure of an internal combustion engine and producing a boost pressure signal corresponding thereto, means for determining a load bias signal as a function of the engine speed signal, and means for producing an adjusted load bias signal as one of the load bias signal and an acceleration-adjusted load bias signal, wherein the acceleration-adjusted load bias signal is based on the boost pressure signal and the engine speed signal.
In accordance with another aspect of the present invention, a method of producing an adjusted load bias signal to provide for optimal acceleration conditions for an internal combustion engine comprises the steps of sensing engine rotational speed, sensing engine intake air pressure, determining a load bias signal as a function of the engine rotational speed, determining an acceleration-adjusted load bias signal based on the engine rotational speed and the engine intake air pressure, and producing an adjusted load bias signal as one of the load bias signal and the acceleration-adjusted load bias signal.
In accordance with a further aspect of the present invention, a system for producing an adjusted load bias signal to provide for optimal deceleration conditions for an internal combustion engine comprises means for sensing engine rotational speed and producing an engine speed signal corresponding thereto, means for determining a reference engine speed, means for determining a load bias signal as a function of the engine speed signal, and means for producing an adjusted load bias signal as one of the load bias signal and a deceleration-adjusted load bias signal, wherein the deceleration-adjusted load bias signal is based on the engine speed signal and the reference engine speed.
In accordance with yet another aspect of the present invention, a method of producing an adjusted load bias signal to provide for optimal deceleration conditions for an internal combustion engine comprising the steps of sensing engine rotational speed, determining a reference engine speed, determining a load bias signal as a function of the engine rotational speed, determining a deceleration-adjusted load bias signal based on the engine rotational speed and the reference engine speed, and producing an adjusted load bias signal as one of the load bias signal and the deceleration-adjusted load bias signal.
In accordance with still another aspect of the present invention, a system for producing an adjusted load bias signal to provide for optimal acceleration and deceleration conditions for an internal combustion engine comprises means for sensing engine rotational speed and producing an engine speed signal corresponding thereto, means for sensing intake air pressure of an internal combustion engine and producing a boost pressure signal corresponding thereto, means for determining a reference engine speed, and a control computer computing a load bias signal as a function of said engine speed signal, the control computer computing an acceleration-adjusted load bias value as a function of the engine speed and boost pressure signals and computing a deceleration-adjusted load bias value as a function of the engine speed signal and the reference engine speed, the control computer producing an adjusted load bias signal as one of the load bias signal, the acceleration-adjusted load bias value and the deceleration-adjusted load bias value.
In accordance with still a further aspect of the present invention, a method of producing an adjusted load bias signal to provide for optimal acceleration and deceleration conditions for an internal combustion engine comprising the steps of sensing engine rotational speed of an internal combustion engine, sensing engine intake air pressure, determining a reference engine speed based on operator requested torque, determining a load bias signal as a function of the engine rotational speed, determining an acceleration-adjusted load bias signal based on the engine rotational speed and the engine intake air pressure, determining a deceleration-adjusted load bias signal based on the engine rotational speed and the reference engine speed, and producing an adjusted load bias signal as one of the load bias signal, the acceleration-adjusted load bias signal and the deceleration-adjusted load bias signal.
One object of the present invention is to optimize the performance of the engine and improve responsiveness and driveability of the vehicle in which the engine is placed.
Another object of the present invention is to provide such optimization by modifying the load bias signal for optimum engine performance during engine acceleration conditions.
Yet another object of the present invention is to provide such optimization by modifying the load bias signal for optimum engine performance during engine deceleration conditions.
These and other objects of the
Janic Dusan M.
McGuire Michael J.
Moore Howard E.
Barnes & Thornburg
Cummins Engine Company, Inc.
Wolfe Willis R.
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