GB2106278A

GB2106278A - Optimising an automatic control system

Info

Publication number: GB2106278A
Application number: GB08225130A
Authority: GB
Inventors: Sydney Himmelstein
Original assignee: Himmelstein & Co S; S HIMMELSTEIN AND Co
Current assignee: Himmelstein & Co S; S HIMMELSTEIN AND Co
Priority date: 1981-09-14
Filing date: 1982-09-03
Publication date: 1983-04-07
Also published as: GB2106278B; JPS5875211A; DE3233193A1

Abstract

A control system has sensors of output power 332, 333 and input power 324 from which an efficiency value is computed and the load adjusted until an optimum value is obtained. In alternative embodiments an input power parameter may be adjusted to obtain the optimum value. Motive power is obtained from an i.c. engine, as shown, or an electric or hydraulic motor. <IMAGE>

Description

SPECIFICATION Improvement in energy efficient drive system Background of the invention Field of the invention This invention relates to drive systems and in particular to means for controlling drive systems so as to obtain maximum efficiency thereof.

Description of the background art It is becoming increasingly critical to obtain maximum efficiency in the utilization of energy such as in the operation of drive systems. It has long been known that individual motive devices, such as internal combustion engines and the like, have readily determinable operating characteristics such that an optimum operation of the motive device for a given load power and speed may be determined. While such characteristics have been available, no one heretofore has been able to develop suitable control apparatus for efficient utilization of such determinable characteristics.

More specifically, the known systems for increasing efficiency in the utilization of motive drives have utilized a wide range of different apparatuses and methods directed to different parameters of the drive system which, at best, have effected less than maximum efficiency of the drive devices. Illustratively, variations in internal combustion cylinder construction, compression ratios, a fuel atomization, etc., have been developed toward the end of improving efficiency in the operation of drive devices, such as internal combustion devices. Transmissions have been developed utilizing higher speed gear ratios for permitting the driving of the load at high speed under reduced power requirements with the motor or engine operating at reduced speeds.

Summary of the invention The present invention comprehends an improved system for obtaining effectively maximum energy usage efficiency in the operation or driving of a load. The system is adapted for use in controlling substantially all forms of input power devices, such as fuelconsuming engines, motors, etc. The system is advantageously adapted for use in controlling the operation of an internal combustion engine and, thus, is advantageously adapted for improving the efficiency in the utilization of automotive vehicle engines.

In my prior development, a drive system utilized means for adjusting the variable transmission of the system in accordance with a determination of load power, load speed, and necessary adjusted speed ratio of the transmission to cause the motive device speed to be a minimum in providing the desired load power and speed.

In another of my prior developments, the motive device comprised a multicylinder internal combustion engine and the adjustment of the motive device is effected by adjusting the engine, such as by adjusting the number of active cylinders in the engine, i.e, the number of cylinders to which fuel is delivered in the operation.

In still another form of my prior developments, the brake specific energy consumption is constantly monitored in the use of the drive system and a determination made as to whether the brake specific energy consumption is decreasing or increasing effectively instantaneously. As a result of such determination, the drive is transmission adjusted.

Where the adjustment effects a decrease in the brake specific energy consumption, the adjustment is continued in the same direction until the adjustment effects an increase in the brake specific energy consumption whereupon the adjustment is reversed. Such adjustments may be continuously effected so as to maintain operation of the drive system under effectively maximum efficiency.

The present drive system is adapted for use with loads wherein the power requirements vary at a constant speed as well as where the load power requirements and speed jointly vary. The drive system is advantageously adapted not only for use with spark ignition engines but equally as well for use with compression ignition engines.

In another form, the drive system effectively comprises a compound device where a variable speed engine drives an adjustable variable load.

The invention comprehends determining the ratio between the output power and the input power to the drive and continuously adjusting the load to achieve the maximum efficiency.

In carrying out the present invention, it is not necessary to determine the characteristics of the drive or load as only the input power and output power need be determined to permit operation of the system at maximum efficiency.

The invention alternatively comprehends operating such a compound system at a maximum output power preselected to be below an upper limit, avoiding machine damage.

In still another form, the invention comprehends a method of achieving optimum efficiency in driving a load from an adjustable drive, such as an engine, by adjusting the operating conditions of the engine.

Where the engine comprises a multicylinder engine, the invention comprehends the adjustment of the operating conditions of each cylinder individually or concurrently, as desired.

The invention comprehends switching from one method of control to any other and the use of compatible methods of control as discussed above jointly, such as by causing the engine to operate at an optimum efficiency while concurrently causing its load point, or the operation of the compound engine-variable load to be optimized for economy.

The drive system of the present invention is simple and economical of construction while yet providing highly improved energy efficient operation of such systems in a novel and simple manner.

Brief description of the drawing Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein: Figure 1 is a schematic illustration of a drive system embodying the invention; Figure 2 is a schematic illustration of another form of drive system embodying the invention; Figure 3 is a schematic illustration of yet another form of drive system embodying the invention; and Figure 4 is a schematic illustration of a further form of drive system embodying the invention.

Description of the preferred embodiment In the exemplary embodiment of the invention as illustrated in Figure 1 of the drawing, an energy efficient drive system generally designated 310 is illustrated in connection with an adjustable load, such as an adjustable output compressor. Thus, in the illustrated embodiment, the drive/load system represents a compound device comprising an engine-driven variable volume compressor.

As shown in Figure 1, the variable load V is driven by an internal combustion engine 31 3 defining the prime mover of the system. Fuel for operating the engine is provided from a conventional fuel supply 325 and the rate of fuel flow from fuel supply 325 to engine 313 is sensed by a conventional fuel flow transducer 324.

Where the variable load comprises a variable compressor V, fluid is delivered to the compressor from a fluid input 328, with the compressed fluid being delivered from the compressor through an outlet 329.

A conventional load adjustment controller 330 is provided for adjusting the variable compressor.

Controller 330 is controlled by an efficiency computer 331, which may comprise any suitable conventional computer well-known to those skilled in the art for providing an output signal as a function of a number of sensed and calculated inputs.

More specifically, the control, as shown in Figure 1, further includes an output compressor head transducer 332 and an output flow transducer 333 of conventional construction for sensing the output head and output flow rate of the compressed fluid in the outlet 329. The sensed determinations of head and fluid flow are delivered to efficiency computer 331. Also as shown in Figure 1, a signal is delivered from the engine fuel flow transducer 324 to the efficiency computer, which provides a calculation of overall efficiency, that is, the ratio of compressor output to the rate of flow of engine fuel to the engine 313. This ratio signal is delivered to the load adjusting controller, which, in turn, correspondingly adjusts the compressor to maximize the ratio and thereby maximize the overall efficiency of the combined engine and compressor.

As indicated briefly above, the variable load may be alternatively controlled to provide maximum output. For this purpose, a mode selector switch 334 is associated with the efficiency computer 331 to permit selective control of the compressor either to provide maximum efficiency or maximum power, or, in the illustrated embodiment, provide a maximum delivered product. As will be obvious to those skilled in the art, in the use of the system to provide maximum compressor output, the efficiency computer disregards the signal from the engine fuel flow transducer 324.

Thus, the control of the variable load V is effected by a suitable determination of the effective reciprocal of brake specific fuel consumption of the combined variable load and variable engine drive. The maximum overall efficiency is obtained by continuously adjusting the load V rather than the adjustable ratio transmissions as in the prior discussed embodiments. Resultingly, it is not necessary to determine the characteristics of either the engine 31 3 or the load apparatus V. Whatever the characteristics of the engine and load, efficiency computer 331 determines the efficiency ratio and load adjusting controller 330 constantly adjusts the loads so as to maximize that determined efficiency ratio.

When utilizing the maximum power mode, the computer 331 may include means for limiting the maximum output of the compressor to an upper, preselected limit to avoid damage to the compressor or drive, and, thus, the concept of maximum power comprehends the limitation to a preselected practical maximum power commensurate with the parameters of the system.

While the invention has been described in connection with an engine-driven compressor, as will be obvious to those skilled in the art, the prime mover may comprise any form of prime mover, including an electric motor, fluid-operated motor, etc. Similarly the load may comprise any form of load device which may be adjusted. The invention comprehends the determination of the load instantaneously so as to provide an instantaneous efficiency ratio of the compound device represented by the variable prime mover and variable load.

The method of efficiency control illustrated in Figure 1 does not require the optimizing of engine or prime mover performance. Thus, it may be that in the optimum efficiency operation, the prime mover operates at less than optimum efficiency and alternatively, it may be that the load may operate at less than optimum efficiency. The inventive concept comprehends that the ratio of output power to input power be optimized and this, in accordance with the invention, may be obtained independently of the optimizing of characteristics of either of the prime mover or load.

The invention comprehends that the prime mover may be connected to the load either directly as shown in Figure 1, or through an adjustable ratio transmission as described in connection with the prior described embodiments. While the invention does not require the optimizing of the primer mover or load efficiencies, it does not require that neither of these be, in fact, effected. Thus, for example, the engine 313 may be caused to operate at its maximum efficiency independently of the maximizing of the ratio of the output power to the input energy.

Referring now to Figure 2, another method of providing improved efficiency in the operation of a driven variable load V differs from the previous described embodiments in utilizing changes in the characteristics of the engine to achieve the desired optimum efficiency. In the illustrated embodiment, the control comprises a brake specific fuel consumption computer 423.

In the illustrated embodiment, the computer 423 controls a characteristic of the engine, such as the point of injection of fuel to the engine 413 where the engine comprises a fuel injection engine. As shown in Figure 2, computer 423 provides a control signal to an adjuster controller 419 for controlling the engine adjustment means 436 which, in the illustrated embodiment, comprises means for adjusting the point of injection of the fuel to the engine 413.

The fuel flow transducer 424 senses the rate of fuel flow to the engine computer 423.

A load transducer 437 operatively associated with the load provides a first signal corresponding to the output speed of the load and a second signal correspoinding to the output torque of the load to an output power computer 438, which provides an output power signal to the computer 423 for use in combination with the fuel flow signal from transducer 424 in computing the brake specific fuel consumption of the engine.

As in the embodiment of Figure 1, a mode selector switch 434 may be provided for selectively re-arranging the control to provide maximum power in lieu of maximum efficiency when desired.

In the operation of the system of Figure 2, the load output power is compared with the rate of fuel flow to the engine to determine the brake specific fuel consumption and by means of a signal from the computer 423 to a conventional adjuster controller 41 9 adjust the point of fuel injection to the engine controlled by the engine adjuster 436. Thus, the method is applicable to both spark ignition and compression ignition engines having fuel injection fuel delivery means.

Where the engine utilizes a carburetor or the like, the timing of the spark may be controlled by controller 419 through a corresponding engine adjuster 436.

In multicylinder engines, the cylinders may be adjusted concurrently or individually, as desired, within the scope of the invention.

In the embodiment of Figure 2, a single engine parameter is adjusted. As will be obvious to those skilled in the art, any number of engine variables may be adjusted within the scope of the invention, including air-fuel ratio adjustment, valve timing, ignition timing, etc.

As will be further obvious to those skilled in the art, the control provided by the method of Figure 2 may be utilized in combination with the other techniques described above.

In Figure 3, an embodiment of the invention utilizing an electric motor as the prime mover is illustrated in schematic form. Thus, as shown in Figure 3, the electric motor 539 receives electric power from a conventional power source 525 through a voltage controller 540 and an electric power transducer 541 of conventional construction. A signal is delivered from the electric power transducer 541 to an efficiency computer 531 similar to efficiency computer 331 of the embodiment of Figure 1.

The electric motor drives the load 512 and a load transducer 517 provides a signal to a power computer 518, which may inciude a torque signal and a speed signal. A load power signal is delivered from computer 5289 to the efficiency computer 531.

Efficiency computer 531 accepts the input power signal from the transducer 541 and the output power signal from the computer 518 and computes in the conventional manner the ratio therebetween to provide an output efficiency signal to the voltage controller for adjusting the voltage supplied to the electric motor 539 for maximizing the efficiency continuously in the operation of the drive system.

As will be obvious to those skilled in the art, the control of the voltage of the power supply to the electric motor is one method only of controlling the operation of the electric motor to provide maximum efficiency in the drive system.

Thus, illustratively, the system may be utilized with variable speed motor mechanisms having independent speed control loops, etc.

Referring now to the embodiment of Figure 4, a fluid-operated motor 641 is illustrated as driving a variable load, such as pump 612. A head transducer 642 measures the head across hydraulic motor 641 to provide a pressure head signal to the efficiency computer 631.

A pump head transducer 643 receives pressure signals from the fluid input supply 628 and the output of the pump 612. The pump head transducer provides a pump head signal to the efficiency computer 631.

The pump output flow is sensed by a transducer 633 and a signal corresponding thereto is also delivered to the efficiency computer 631. A fluid power source, such as hydraulic power source 625, provides pressurized fluid to motor 641 through a fluid flow controller 640. The input flow is sensed by a transducer 644 which provides a signal to the efficiency computer 631 corresponding thereto.

Efficiency computer 631 determines the efficiency of the system in a conventional manner and provides a system efficiency signal to the flow controller signal 640 so as to maximize the efficiency of the system continuously by suitably controlling the fluid flow delivery to the hydraulic motor 641.

Illustratively, efficiency computer 631 determines the ratio of the output to the input of the system where the output is determined by the output flow and the output head and the input is determined by the input fluid flow and the input head.

In the different embodiments illustrated in the drawing, corresponding elements are designated by similar reference numerals but 100 different.

As indicated above, the different drive systems function in similar manners except as specifically discussed. Broadly, the different methods contemplated by the invention include optimizing efficiency by changing the gear ratio of the transmission means or changing the number of cylinders to permit the engine to run at optimum efficiency for a given load. Further, alternatively, the invention comprehends the constant adjustment of a variable load to provide maximum output to input efficiency. Still further alternatively, the invention comprehends constantly adjusting the engine operating conditions to obtain maximum output-input efficiency, such as by adjusting the point of injection in a fuel injection engine or the spark timing of a carburetor-type engine. Still further, the invention comprehends the control of the drive system so as to provide maximum permissible power, or drive output, within the safety parameters of the system. The possibility of such selection of the maximum power mode permits improved facility in the control of a drive system where at times it is desirable to provide maximum output rather than maximum efficiency in the safe operation of the system or as otherwise desired.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

Claims

1. The method of effictively optimizing energy usage efficiency in a drive system having an energy-using prime mover and a variable load driven by the primer mover, comprising the steps of: determining the instantaneous rate of energy usage by the prime mover; determining the instantaneous power being produced in the load; and continuously adjusting the load to maximize the drive system efficiency.

2. The method of effectively optimizing energy usage efficiency of Claim 1 wherein the load is directly connected to the primer mover.

3. The method of effectively optimizing energy usage efficiency of Claim 1 wherein the load is connected to the prime mover through a variable transmission, and said method further includes the step of adjusting the transmission.

4. The method of effectively optimizing energy usage efficiency of Claim 1 wherein the load comprises a device for performing work on a fluid.

5. The method of effectively optimizing energy usage efficiency of Claim 1 further including the step of adjusting the speed of the primer mover to obtain operational efficiency thereof prior to said step of adjusting the load.

6. The method of effectively optimizing energy usage efficiency in a drive system having a prime mover which is constructed to be variably arranged for providing a variable power drive, and a load drive by the prime mover, comprising the steps of: determining the instantaneous brake specific fuel consumption by the primer mover; and adjusting the operating conditions of the prime mover to effectively minimize the brake specific fuel consumption.

7. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the engine comprises a fuel injection engine, and the step of adjusting the operating conditions of the engine comprises a step of adjusting the point of injection of fuel thereto.

8. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the prime mover comprises an engine and the step of adjusting the operating conditions of the engine comprises a step of adjusting the ignition timing of the engine.

9. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the prime mover comprises a multicylinder engine having a plurality of cylinders, and the step of adjusting the operating conditions of the primer mover comprises a step of adjusting sequentially the arrangement for each cylinder.

10. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the prime mover comprises an engine and the step of adjusting the operating conditions of the engine comprises a step of adjust the ratio of air fuel delivered thereto.

11. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the prime mover comprises an engine and the step of adjusting the operating conditions of the engine comprises a step of adjusting the valve timing of the engine.

12. The method of effectively optimizing energy usage efficiency of Claim 6 wherein the prime mover comprises an engine having a plurality of cylinders, and the step of adjusting the operating conditions of the prime mover comprises a step of adjusting the operating conditions of all of the cylinders concurrently.

13. The method of effectively optimizing energy usage efficiency of Claim 6 wherein at least two different operating conditions are adjusted in effecting said adjustment of the operating condition of the primer mover.

14. The method of effectively optimizing energy usage efficiency of Claim 6 wherein said prime mover comprises an internal combustion engine.

1 5. The method of effectively optimizing energy usage efficiency of Claim 6 wherein said prime mover comprises an electric motor.

1 6. The method of effectively optimizing energy usage efficiency of Claim 6 wherein said prime mover comprises a fluid-operated motor.

1 7. In a drive system having a drive responsive to variable input energy to drive a variable load at variable speed, the improvement comprising: means for determining the output power of the load; means for determining the input power; and means for adjusting the ratio of output power of the load to the input power as determined by said determining means to obtain maximum efficiency in operation of the drive system.

1 8. The drive system of Claim 17 wherein said drive comprises an internal combustion engine.

19. The drive system of Claim 1 7 wherein said drive comprises an internal combustion engine and a variable speed transmission connected between the engine and load.

20. The drive system of Claim 17 wherein said means for adjusting said ratio comprises means for adjusting said load.

21. The drive system of claim 17 wherein said means for adjusting said ratio comprises means for adjusting said drive.

22. The drive system of Claim 17 wherein said drive comprises an electric motor.

23. The drive system of Claim 17 wherein said drive comprises a fluid-operated motor.

24. In a drive system having a prime mover responsive to variable input energy to drive a load at variable speed with the maximum efficiency of utilization of the input energy being obtained by operating the drive system at minimum brake specific energy consumption necessary to produce a desired load speed and power, the improvement comprising: means for determining the load power, load speed, and necessary adjustment of said prime mover to cause said brake specific energy consumption to be a minimum in providing the desired load power and speed; and means for adjusting said prime mover in accordance with the determined adjustment thereby to obtain minimum brake specific energy consumption operation of the drive.

25. In a drive system having a drive responsive to variable input energy to drive a variable load at variable speed, the improvement comprising: means for determining the input power of the load; means for determining the rate of energy input to the drive; and means for adjusting at ieast one of said drive and said load in accordance with the determinations of said determining means to obtain a maximum power of the load without damage to the drive system.

26. The drive system of Claim 25 wherein said drive comprises an internal combustion engine.

27. The drive system of Claim 25 wherein said drive comprises an internal combustion engine and a variable speed transmission connected between the engine and load.

28. The method of operating a drive system having an energy-using prime mover and a load driven by the prime mover, comprising the steps of: determining the power input to the prime mover; determining the output of the load; and continuously selectively (a) adjusting one or both of the load and the prime mover to maximize the drive system efficiency, or (b) maximize the power of the load without damage to the drive system.

29. The method of operating a drive system of Claim 28 wherein the prime mover comprises an internal combustion engine and is adjusted by adjusting the arrangement of the engine.

30. The method of operating a drive system of Claim 28 wherein the prime mover comprises an internal combustion engine and is adjusted by adjusting the operating point of the engine.