Vehicle accessory power management assembly

A vehicle accessory power management assembly includes a vehicle speed sensor, an accelerator sensor, an accessory device, a power transmitting device and a controller. The power transmitting device receives rotational power from a power device and transmits it to the accessory device. The power transmitting device is switchable between a first operating state and a second operating state. In the first operating state the accessory device is operated at a first power consumption level and in the second operating state the accessory device is operated at a second power consumption level lower than the first power consumption level. The controller is configured to switch the switching part from the first operating state to the second operating state in response to determining that a current level of acceleration requested of the power device is of greater importance than operating the accessory device at the first operating state.

BACKGROUND

Field of the Invention

The present invention generally relates to a vehicle accessory power management assembly. More specifically, the present invention relates to a power transmitting device that reduces the power consumption level of a vehicle accessory supplied with power from a power device in response to a determination that current acceleration of the power device is of greater importance than operation of the vehicle accessory at a higher power consumption level.

Background Information

Vehicles with accessories, such as, for example, an air conditioning system and an alternator, experience power draws on the power device (engine) under heavy acceleration when the accessories are operating. In particular, vehicles with small engines exhibit more rapid acceleration when the air conditioning system is shut off.

SUMMARY

One object of the present disclosure is to a vehicle with an accessory power management assembly that reduces the consumption of power used by accessories when it is determined that acceleration is of greater importance than operation of the accessories.

In view of the state of the known technology, one aspect of the present disclosure is to provide a vehicle with an accessory power management assembly that includes a vehicle speed sensor, a power device, an accelerator sensor, an accessory device, a power transmitting device and a controller. The vehicle speed sensor is configured to detect a current speed of a vehicle. The power device is configured to produce rotary power that powers the vehicle. The accelerator sensor is configured to detect a current of level of acceleration requested of the power device. The accessory device is supported to the power device. The power transmitting device is coupled to the power device receiving rotational power therefrom. The power transmitting device is also coupled to the accessory device. The power transmitting device is switchable between a first operating state and a second operating state. In the first operating state the accessory device is provided with rotary power from the power device via the power transmitting device at a first power consumption level. In the second operating state the accessory device is provided with rotary power from the power device via the power transmitting device at a second power consumption level that is lower than the first power consumption level. The controller is connected to the vehicle speed sensor, the accelerator sensor and the power transmitting device. The controller is configured to switch the switching part from the first operating state to the second operating state in response to the controller determining that at the current speed of the vehicle the current level of acceleration requested of the power device is of greater importance than operating the accessory device at the first operating state.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring initially toFIG. 1, a vehicle10having is illustrated in accordance with a first embodiment. As shown inFIG. 2, the vehicle10includes a vehicle body structure12that defines a passenger compartment14, a power device16, a plurality of accessories, such as an alternator18and an air conditioning system20, and a vehicle accessory power management assembly22.

The power device16is a primary power producing mechanism within the vehicle10, where the power device16provides propulsion torque that moves the vehicle10. For example, the power device16can be any of a variety of power producing mechanisms, such as a diesel fuel internal combustion engine, a gasoline fuel internal combustion engine, a hydrogen powered engine (or fuel cell), an electric motor, or hybrid power plant that includes both an electric motor and a hydrocarbon fuel powered engine. The power device16also includes a transmission (not shown) and drive shaft(s) (not shown) that provide rotary power to at least two of the wheels of the vehicle10.

The power device16includes a belt24that is rotated by an output shaft (not shown) of the power device16in a conventional manner. The power device16also includes conventional features such as a starter mechanism (not shown) and an accelerator pedal (not shown) that is manipulated by a vehicle operator to control the speed of the vehicle10and change the level of acceleration of the power device16. Since power devices, such as the power device16are conventional vehicle mechanisms, further description is omitted for the sake of brevity.

The alternator18is a conventional vehicle component that produces electricity for use within the vehicle10, and in particular, is connected to a battery26in order to recharge the battery26in a conventional manner. The alternator18includes a first power transmitting device28that is switchable between a first operating state and a second operating state. In the first operating state the alternator18(an accessory device) is provided with rotary power from the power device16via the power transmitting device28at a first power consumption level and in the second operating state the alternator18is provided with rotary power from the power device16via the power transmitting device28at a second power consumption level, as described in greater detail below. The first power transmitting device28includes a pulley that engages the belt24such that the first power transmitting device28receives rotary power from the power device16via the belt24.

The air conditioning system20includes a compressor30, a condenser32and an evaporator34. Since compressors, condensers and evaporators are conventional components of air conditioning systems, further description of the compressor30, the condenser32and the evaporator34is omitted, except for those specific details and features that assist in understanding the inventions described herein.

The compressor30includes a second power transmitting device40. Like the first power transmitting device40, the second power transmitting device40is switchable between a first operating state and a second operating state. In the first operating state the compressor30is provided with rotary power from the power device16via the second power transmitting device40at a first power consumption level and in the second operating state the compressor30is provided with rotary power from the power device16via the second power transmitting device40at a second power consumption level, as described in greater detail below. The second power transmitting device40also includes a pulley that engages the belt24such that the second power transmitting device40receives rotary power from the power device16via the belt24.

As shown schematically inFIG. 3, the vehicle accessory power management assembly22includes a controller42, a temperature sensor44, a power sensor46, a speed sensor48and an accelerator sensor50. The controller42is connected to each of the first power transmitting device28, the second power transmitting device40, the temperature sensor44, the power sensor46, the speed sensor48and the accelerator sensor50. The controller42uses data received from selected ones of the temperature sensor44, the power sensor46, the speed sensor48and the accelerator sensor50in order to control operation of the first power transmitting device28and the second power transmitting device40, as is described in greater detail below.

The temperature sensor44is configured to measure temperature either within the passenger compartment14, or the temperature of air that has been cooled passing over cooling surfaces of the evaporator34in a conventional manner. The location of the temperature sensor44can vary vehicle-to-vehicle. For example, the temperature sensor44can be located within the passenger compartment14, or can be located adjacent to or downstream of the evaporator34within an air handler34athat houses the evaporator34.

The power sensor46is connected to one or both of the battery26and the alternator18and is configured to detect one or both of the level of charge of the battery and/or the electrical demands being placed on the alternator18and battery26. The electrical demands placed on the alternator18and battery36include, for example, operation of the blower motor34bwithin the air handler housing34a, operation of an audio system (not shown) within the vehicle10, or other electrical devices (not shown). Further, the power sensor46can be configured to detect the health and/or status of the charge of the battery26by detecting voltage output level and reactions to changes in loads applied to the battery26and/or the alternator18during usage of electrical devices within the vehicle10.

The speed sensor48of the vehicle accessory power management assembly22is configured to measure and output signals representing the current speed of the vehicle10. The speed sensor48can be located on the power device16, on a transmission (not shown) attached to the power device16, or any other conventional location within the vehicle10to measure speed of the vehicle10. The accelerator sensor50is configured to measure and output signals representing changes in the speed of the vehicle10. Specifically, the accelerator sensor50is coupled to, for example, the accelerator pedal (not shown) of the vehicle10, or to the throttle body (not shown) of the power device16, to measure the level of acceleration currently being requested of the power device16. For example, if a vehicle operator or a cruise control mechanism (not shown) is in the process of manipulating the throttle or accelerator of the power device16, the accelerator sensor50measures level of acceleration and sends corresponding signals to the controller42so that the controller42can process the data corresponding to the current level of acceleration, as is described in greater detail below.

In the first embodiment, the first power transmitting device28is installed to the alternator18in a conventional manner and the second power transmitting device40is installed to the compressor30in a conventional manner. In the first embodiment, both the first power transmitting device28and the second power transmitting device40are conventional electromagnetic clutch mechanisms. However, as shown in further embodiments, the first power transmitting device28and the second power transmitting device40can be any of a variety of power transmitting mechanisms, as described below. Further, since the first power transmitting device28and the second power transmitting device40are both powered by the power device16via the belt24, in an alternative embodiment it is possible to replace the first power transmitting device28and the second power transmitting device40with a single power transmitting device located at the main crankshaft of the power device16, as described in greater detail below.

In the first embodiment, one or both of the first power transmitting device28and the second power transmitting device40are controlled by the controller42in order to switch the operation of the alternator18and the compressor30between a normal operating condition and a compromise operating condition in response to conditions where the power device16needs to provide rapid acceleration to the vehicle10, as is described in greater detail below. In the normal operating condition, the first power transmitting device28and the second power transmitting device40are provided with power from the power device16at a first power consumption level where alternator18and the compressor30can use the power they need from the power device16without hindrance. In the compromise operating condition, the alternator18and the compressor30are operated at a second power consumption level where power consumption is reduced or eliminated (lower than the first power consumption level) thereby allowing the power device16to provide an unencumbered level of power for acceleration of the vehicle10. In the first embodiment, the second power consumption level includes depriving one or both of the alternator18and the compressor30of rotary power from the power device16for a predetermined length of time, as is described in greater detail below. In other embodiments, the second power consumption level can be a reduction in power provided by the power device16, not necessarily a complete lack of power.

A description of a basic outline of the logic implemented by the controller42is now provided initially with reference to the steps depicted inFIG. 4. As shown schematically inFIG. 4, the controller42is configured at step S1to determine which of the accessories are currently being operated. In the first embodiment, for example, the alternator18and the compressor30of the air conditioning system20are the only two accessories depicted. It should be understood that there can be additional accessories and that the depiction of the alternator18and the compressor30are examples used to explain the implementation of the present invention.

At step S1, the controller42determines whether one or both of the alternator18and the compressor30is requiring rotary power from the power device16. The alternator18is typically always using at least a small level of rotary power from the power device16to produce electric power for devices within the vehicle10that require electric power. The alternator18also selectively provides power to the battery26in order to recharge the battery in a conventional manner.

The compressor30primarily only uses rotary power from the power device16when the air conditioning system20is in operation in order to cool or dehumidify the passenger compartment14. For the purpose of explaining operation of the vehicle accessory power management assembly22and more specifically, operations of the controller42, it is assumed in the description of the flowcharts depicted inFIGS. 5 and 6that both the alternator18and the compressor30are using rotary power from the power device16.

In vehicles with small motor corresponding to the power devices16, the controller42can be configured to reduce or cut off power consumption of both the first power transmitting device28and the second power transmitting device40when acceleration of the vehicle10is determined to be more important than operation of accessories. Alternatively, in a vehicle with a more powerful motor (corresponding to the power device16), the alternator18can be provided with rotary power at all times, possibly eliminating the need for the first power transmitting device28, and the controller42can be configured to only reduce rotary power consumption of the compressor30when acceleration of the vehicle10is more important than operation of accessories.

For the sake of simplicity, in the description below of operations depicted inFIGS. 4, 5 and 6, it is assumed that in step S1the controller30determined that only the second power transmitting device40, and hence the compressor30, is to be manipulated or have its operating condition changed when the controller42determines that acceleration is more important than powering accessories.

At step S2, the controller30determines the speed of the vehicle10via signals from the speed sensor48and determines the amount of acceleration being requested via signals from the accelerator sensor50. Based on the conditions met when evaluating the data from the speed sensor48and the accelerator sensor50, the controller42further determines whether or not acceleration of the vehicle10is more important than operation of accessories. One example of logic used to determine whether or not acceleration of the vehicle10is more important than operation of accessories is shown inFIG. 5and is described in greater detail below.

As step S3inFIG. 4, the controller42implements a change in the power level made available to the accessory or accessories based on the determination made in step S2. One example of the logic represented by step S3is depicted inFIG. 6and is also described in greater detail below.

A description is now provide of the logic shown inFIG. 5. The logic inFIG. 5includes steps for determining which is of greater importance, acceleration of the vehicle10at the current speed of the vehicle10, or providing power to the accessories at the first power consumption level, where full power is provided to the accessory. It should be understood from the drawing and the description herein that there are many different ways to determine the importance of acceleration vs. the operation of accessories. The logic presented inFIG. 5is just one example of such logic based upon speed of the vehicle and the level of acceleration requested of the power plant16.

The following acronyms are used in the description ofFIG. 5below. Specifically, APO is an abbreviation of Accelerator Pedal Opening and is a variable representing the signals sent from the accelerator sensor50and measurements of current levels of vehicle acceleration. If APO is equal to 100 percent, then APO indicates that acceleration requested by the vehicle operator is at a maximum. In other words, if APO is equal to 100 percent then the vehicle operator has pressed the acceleration pedal all the way to the floor (full throttle requested of the power device16). If APO is equal to zero percent, then APO indicates that no acceleration has been requested by the vehicle operator. In other words, acceleration is at a minimum or the vehicle operator has his foot completely off the accelerator pedal.

VSP is an abbreviation of Vehicle Speed and is a variable representing the signals sent from the speed sensor48and measurements of levels of speed of the vehicle10. FLG is merely a variable that is used to define the determination made by the controller42using the logic inFIG. 5. When FLG is made equal to one (1), the controller42has made the determination that at the current speed VSP of the vehicle10the current level of acceleration APO requested of the power device16is of greater importance than operating the accessory device at the first operating state. When FLG is made equal to zero (0) then the controller42has determined that at the current speed of the vehicle10the current level of acceleration requested of the power device16is not of greater importance than operating the accessory devices at the first operating state.

At step S10, the controller42checks the data from the accelerator sensor50. If APO is equal to or less than 75%, then operation moves to step S11. If APO is greater than 75%, then operation moves to step S12. Movement to step S12indicates that heavy acceleration has been requested of the power device16by the vehicle operator.

At step S11, the controller42further checks the data from the accelerator sensor50. If APO is equal to or less than 40%, then operation moves to step S13. If APO is greater than 40%, then operation moves to step S14. Movement to step S14indicates that a high level of acceleration that is less than the heavy acceleration level at step S10and S12has been requested of the power device16by the vehicle operator.

At step S13, the controller42further checks the data from the accelerator sensor50. If APO is equal to or less than 25%, then operation moves to step S15. If APO is greater than 25%, then operation moves to step S16. Movement to step S16indicates that a moderate level of acceleration less than the high level acceleration level at steps S11and S14has been requested of the power device16by the vehicle operator.

Returning to step S12, the value of APO at Step S10was of a sufficient level to move to step S12. At step S12, the controller42reads the data from the speed sensor48. If the vehicle speed VSP is equal to or greater than 90 miles per hour (mph) then operation moves to step S11. If the vehicle speed VSP is less than 90 mph then operation moves to step S17here the variable FLG is made equal to 1 indicating that the acceleration of the vehicle10is more important than operation of accessories.

At step S14, the value of APO at Step S11was of a sufficient level to move to step S14. At step S14, the controller42reads the data from the speed sensor48. If the vehicle speed VSP is equal to or greater than 50 mph then operation moves to step S13. If the vehicle speed VSP is less than 50 mph then operation moves to step S17here the variable FLG is made equal to 1 indicating that the acceleration of the vehicle10is more important than operation of accessories.

At step S16, the value of APO at Step S13was of a sufficient level to move to step S16. At step S16, the controller42reads the data from the speed sensor48. If the vehicle speed VSP is equal to or greater than 20 mph then operation moves to step S15where the variable FLG is made equal to zero (0) indicating that the acceleration of the vehicle10is not as important than operation of accessories. If the vehicle speed VSP is less than 20 mph then operation moves to step S17here the variable FLG is made equal to 1 indicating that the acceleration of the vehicle10is more important than operation of accessories.

The values of the variable APO in steps S10, S11and S13used by the controller42in the decision boxes shown inFIG. 5, and the values of the variable VSP in the decision boxes S12, S14and S16are merely examples of such values. The number values shown in the decision boxes S10-S14and S16are example values for demonstration purposes only. For example, for a vehicle having a power device16that has a modest horsepower output of, for example, less than 150 horsepower, the values of the variables APO and VSP will be compared with values that differ from values set for a vehicle having a power device16with a horsepower output of, for example, more than 300 horsepower. More specifically, the values of the accelerator measurement and vehicle speed that the variables APO and VSP are compared with and will differ from model to model. Specifically, the percentages indicated in steps S10, S11and S13are not limiting numbers and can vary from vehicle to vehicle and engine to engine. Similarly the speed (in miles per hour) indicated in steps S12, S14and S16can vary from vehicle to vehicle, and engine to engine.

At the bottom ofFIG. 5, the logic presented designates the value of the variable FLG as being either zero (0) or one (1). If the value of FLG is made equal to zero in step S15, then the acceleration of the vehicle10is not more important than operation of accessories. If the value of FLG is made equal to one in step S17, then the acceleration of the vehicle10is more important than operation of accessories. The variable FLG is further used in the logic presented inFIG. 6.

At the bottom ofFIG. 5, the letter B designates continuing logic inFIG. 6, as described further below with respect to the first embodiment. The letter B′ designates continuing logic inFIG. 7with respect to a second embodiment. In other words, the logic set forth inFIG. 5is used in the first embodiment which continues inFIG. 6and is also used in the second embodiment, shown inFIGS. 7 and 8and described further herein below.

A description of one example of the operations of the controller42implementing changes to the power consumption level(s) of the second power transmitting device40is now described with specific reference toFIG. 6.

As shown inFIG. 6, the controller42continues operations at step S19where the controller42determines whether or not accessory operation is critical or not. If accessory operation is critical, then operation moves to step S21, described further below. If accessory operation is not critical, then operation moves to step S20, as described further below. In step S19, the accessory operation can be deemed critical for any of a variety of reasons. There are many possible accessory operation critical circumstances. For example, if the controller42determines that significant demands are being made on electrical system of the vehicle10, then the accessory operation is critical. Specifically, in a rain storm where wipers are operating, headlights are on, and the air conditioning system is being operated in a defogging mode to draw moisture from the air and off the windshield, would be one example of great demands being made of the alternator18and/or the battery26. Another example of accessory operation critical circumstances include the controller42determining that the evaporator34is at such a high temperature that cooling is clearly required (for example, upon startup of the vehicle10), overriding the need for reduction of power consumption on the power device16.

Step S19is an optional feature and can be omitted in some applications. Next at step S20, the controller42determines whether or not the variable FLG has previously been made equal to one (1). At step S20, if FLG is not equal to one, then operation moves to step S21, where operation of the accessory continues in a normal power level function. The normal power level function corresponds to the first operating state where the compressor30is operated with the second power transmitting device40at the first power consumption level (i.e., with the electromagnetic clutch engaged to receive rotary power from the power device16).

At step S22, the controller42sets redefines a variable Timer to be incrementally reduced (Timer=Timer−1). The variable Timer represents a time period that defines a length of time during which the controller42can operate the second power transmitting device40in the second operating state where the compressor30has a reduced (or eliminated) level of rotary power provided from the power device16while the power device16undergoes acceleration. The variable Timer is initially defined as being equal to 10 seconds, as is further explained below with respect to step S33. However, it should be understood from the drawings and the description herein that the variable Timer can be defined initially to any length of time, depending on the design of the vehicle10and the capacity of the air conditioning system20. For example, in a vehicle10with a power device16that produces a lower level of horsepower, it can be advantageous to initialize the variable Timer as being 15 seconds or 20 seconds to give the power device16plenty of time to undergo acceleration. In a vehicle with a power device16that produces a large level of horsepower, the variable Timer can be initialized as being only 5 seconds or 10 seconds since the power device16may not need a long period of time to undergo acceleration and achieve a desired vehicle speed. In other words, althoughFIG. 6shows the variable Timer as being initialized as being 10 seconds in step S33, the 10 second value is merely one example of the initialization of the variable Timer. The variable Timer can be initialized to a value that can vary from model to model.

Next, operation moves to step S23. At step S23, the controller42determines whether or not Timer is less than zero. If the variable Timer is not less than zero, operation moves to step S24where the controller42operates the second power transmitting device40in a compromise mode (compromise operating condition). In the first embodiment, the compromise mode corresponds to operating the second power transmitting device40in the second operating state where the second power transmitting device40is not operated. Hence, in the second operating state, the second power consumption level is such that the electromagnetic clutch that defines the second power transmitting device40is turned off. Therefore, no rotary power is transmitted between the power device16and the compressor30.

At step S23, if the variable Timer is less than zero, operation moves to step S26, as is described further below.

After step S24, operation moves to step S25. At step S25, another variable TMR2(also referred to as Timer2) is defined as being equal to, for example, 15 seconds. The variable TMR2is defined for the purpose of subsequently temporarily operating the second power transmitting device40in the first operating state in the event that acceleration continues beyond the time allotted for the variable Timer. Specifically, if the vehicle operator is operating the vehicle10with a high level of acceleration for an extended period of time, and the air conditioning system20is operating, after the initialized value for the variable Timer has expired, the controller42overrides the demand for acceleration with reduced power to the accessories, and for the period of time designated in the variable TMR2, the accessories are operated. At the expiration of the time period assigned to the variable TMR2, the controller42again operates the second power transmitting device40in the second operating state. A basic purpose of the variable TMR2is to provide recovery time for accessory function. For example, if the need for cooling or replenishing of battery power becomes more important than the acceleration event, the variable TMR2allows for a way for the accessory function to recover.

As with the initialized value of the variable Timer, the length of time assigned to the variable TMR2varies from model to model. In the embodiment depicted inFIG. 6, the variable TMR2is initialized with a value of fifteen seconds (15 sec.). This value is just one example of the variable TMR2. For example, in a vehicle with an air conditioning system with a large cooling capacity (and a correspondingly powerful compressor), it may only be necessary to initialize the variable TMR2with a value of five seconds or ten seconds. Conversely, in a vehicle with an air conditioning system with a generally small cooling capacity (and a correspondingly low power compressor), it may be necessary to initialize the variable TMR2with a value of fifteen seconds or twenty seconds.

After step S25, operation moves back to the operation inFIG. 5.

Returning to step S23, if the variable Timer is less than zero, operation moves to step S26. At step S26, the variable timer is made equal to zero and operation moves to step S27. At step S27, the variable FLGOFF is made equal to one (FLGOFF=1).

The variable FLGOFF is made equal to one at the end of the time period defined by the variable Timer. During the steps where the value of the variable Timer is incremental diminished (iterations of the logic at step S22), the controller42operates the second power transmitting device40in the second operating state (the compromise mode or compromise operating condition) such that the compressor30is not provided with rotary power. At the end of the time period defined by the variable Timer, the value of FLGOFF determines whether or not the controller42is to temporarily restore operation of the second power transmitting device40in the first operating state.

After step S27where the variable FLGOFF is made equal to one, normal operation of the compressor30is restored at step S21for the period of time designated by the variable TMR2.

At step S28, the controller42checks the value of the variable FLGOFF. If FLGOFF is equal to one (FLGOFF=1) operation moves to step S29. At step S29, the value of the time related variable TMR2is incremented down by one second (TMR2=TMR2−1).

Next at step S30, the controller42determines whether or not the variable TMR2is less than zero (TMR2<0?). If the variable TMR2is less than zero, then the period of time designated for temporarily operating the second power transmitting device40in the first operating state has ended. Therefore, operation moves to step S31where the variable TMR2is re-defined as being equal to zero (TMR2=0). Operation then moves to step S32where the variable FLGOFF is defined as being equal to zero (FLGOFF=0). Operation then moves to step S33.

At step S30, if the variable TMR2is not less than zero operation returns toFIG. 5for the next iteration of the logic.

Returning to step S28, if the controller42determines that the value of the variable FLGOFF is not equal to one (FLGOFF≠1) operation also moves to step S33. At step S33, the variable Timer is re-defined as being equal to ten seconds (Timer=10 sec.) and operation returns to the steps inFIG. 5. Thereafter, if acceleration still continues to be of importance, upon the next iteration of the presented example of the logic used by the controller42, the controller42resumes operating the second power transmitting device40in the second operating state.

In the logic described above, the first power transmitting device28and the second power transmitting device40are characterized as being electromagnetic clutches that transmit full rotary power to the accessories (the alternator18and the compressor30) or disconnect the accessories completely from the power device16such that the accessories are no longer operated. In other words, in the first embodiment, in the first operating state the first power consumption level represents full power being transmitted to the accessories and in the second operating state the second power consumption level represents no power being transmitted to the accessories.

It should be understood from the logic presented inFIGS. 5 and 6that alternative devices can be used as the power transmitting devices. Specifically, conventional electromagnetic clutches discussed above can be replaced with devices that establish the first power consumption level as transmitting full power to the accessories, but establish the second operating state such that the second power consumption level as transmitting a reduced amount of rotary power to the accessories. In other words, the accessories are always provided with at least some rotary power in alternative embodiments, such as those described in greater detail below.

The vehicle accessory power management assembly22is configured such that when a vehicle operator makes acceleration demands on the power device16that can be difficult to achieve with accessories operating, the controller42eliminates or reduces the energy draw of the accessories by temporarily changing the level of power drawn by the accessories from the power plant16. Thus, when the vehicle operator requests heavy acceleration from the power device16, the power device16is able to more easily achieve the current acceleration demands.

Second Embodiment

The logic presented inFIG. 5remains unchanged from the description above with respect to the first embodiment. Therefore, for the sake of brevity, the description of the logic presented inFIG. 5is not repeated here.

In the second embodiment, the compressor30is a variable compression stroke compressor such that an electromagnetic clutch is not necessary in order to change power consumption levels between the first operating state and the second operating state of the compressor30. Rather, the stroke length of pistons that compress refrigerant can be changed in many variable stroke compressors. Variable compressors are conventional devices, such as those disclosed in, for example, U.S. Pat. No. 8,196,506 and U.S. Pat. No. 7,972,118, which are incorporated herein by reference in their entirety.

One aim of the vehicle accessory power management assembly in accordance with the second embodiment is to integrate the driving demand needs into the evaporator temperature management for a variable compressor. Currently with an air conditioning system operating, the evaporator is managed to a target temperature that requires some pumping load to meet cabin comfort that is largely independent of the driving situation. Small transient acceleration demands, such as passing maneuvers or pulling into traffic, are compromised by the energy load demands of the compressor30. This is particularly evident in vehicles having small engine. In the second embodiment, the controller42is configured to reduce compressor power consumption during transient driving circumstances in a manner that better optimizes the combination of cabin comfort needs and acceleration performance.

In the second embodiment and specifically inFIGS. 7 and 8, several variables are referred to. The variable EVPT represents the current temperature at or downstream from the evaporator34as measured by the temperature sensor44.

The variable EVTGT is a target temperature set by the air conditioning system20that corresponds to a temperature at the evaporator34necessary such that air passing over cooling surfaces of the evaporator34are adequately cooled to a temperature that provides comfort to the passenger compartment14and achieves a temperature in the passenger compartment set by a vehicle passenger or the vehicle operator.

The variable TGT is a temporary target temperature that is temporarily redefined inFIG. 7to either the value of the variable EVTGT (step S46) or is set to an arbitrarily high value (step S41) so that in subsequent iterations of the logic the power consumption of the compressor30can be reduced during acceleration events.

The variable Hys is a simple hysteresis number that is determined on a model to model basis. The variable Hys is used by the controller42in a comparison of the variable TGT with the variable EVPT. Specifically, the variable EVPT is compared with the value of TGT plus or minus the variable Hys.

The variable CS corresponds to the current stroke of the variable stroke compressor (the compressor30). The compressor stroke CS is adjustably set by the controller42anywhere within a range from zero (0) where little or no refrigerant is compressed, to 100 where a maximum amount of refrigerant is compressed.

The variable Step is used to redefine the value of the compressor stroke variable CS. The value of the variable Step is determined on a model to model basis and can vary in values from two (2) to ten (10).

In the second embodiment, the air conditioning system20operates the compressor30to maintain temperature at the evaporator34(represented by the variable EVTGT) such that the passenger compartment14is maintained at a comfortable temperature. When the controller42determines that acceleration is of greater importance than operation any accessories (FIG. 5), then the compressor30(a variable stroke compressor) is “de-stroked” until an elevated evaporator temperature is reached which is still acceptable for passenger compartment comfort. At that time, the air conditioning system20controls the compressor30to maintain the evaporator34at an elevated evaporator temperature. The stroke of the compressor30is returned to normal operation, with a lower target evaporator temperature, when controller42determines that acceleration is no longer more important than operation of accessories.

In the second embodiment, the second power transmitting device40is the stroke adjusting mechanism of the variable stroke compressor (the compressor30).

The logic set forth inFIGS. 5, 7 and 8is used by the controller42to first determine whether or not acceleration is of more importance than accessory operation (FIG. 5) and manipulate the variable stroke mechanism (the second power transmitting device40) of the compressor30in order switch operation of the compressor30between the first operating state and the second operating state (FIGS. 7 and 8).

In the second embodiment, the first operating state is such that the compressor30is operated at a first power consumption level as per normal operating protocols of the air conditioning system20. Specifically, a passenger or vehicle operator sets a target temperature that corresponds to comfort in the passenger compartment14. The controller42then determines the evaporator temperature EVTGT (a target temperature) for the evaporator34in a conventional manner and operates the compressor30accordingly to maintain the evaporator temperature EVTGT.

In order to operate the compressor30, the controller42changes the compressor stroke CS within a range from zero (0) where little or no refrigerant is compressed, to 100 where a maximum amount of refrigerant is compressed.

InFIG. 7, the controller42basically redefines the value of the variable TGT used in belowFIG. 8. If acceleration is more important than the operation of the accessories, then TGT is defined with a preset large value. The preset value of TGT is 15° C. inFIG. 7(see step S42). However, it should be understood that the preset value of TGT can vary from model to model. The present value of TGT can vary from between 5° C. to 20° C. In other words, the value depicted inFIG. 7at step S42is merely one example of a preset value of the variable TGT.

The logic set forth inFIG. 7proceeds after the logic presented inFIG. 5. Specifically, all the steps inFIG. 5are acted upon by the controller42, and thereafter, the controller42proceeds to the logic inFIG. 7in the second embodiment. At step S40inFIG. 7, the controller42confirms the target value of the variable EVTGT which is determined based upon the input to the air conditioning system20(climate system) by a vehicle passenger or vehicle operator. In the absence of acceleration of the vehicle10, the air conditioning system20operates the compressor30to achieve the target temperature corresponding the value of the variable EVTGT. At step S41, the controller42determines whether or not the variable FLG is equal to one (1). If at step S41the controller42determines that the variable FLG is equal to one (1), then operation moves to step S42. The value of the variable FLG equal to one (1) indicates that acceleration is more important than operation of accessories.

At step S42, the variable TGT used in the logic shown inFIG. 8is redefined as being equal to the preset value of 15° C. Next in step S43, the controller42determines whether or not the variable NewFlag is equal to one (1). The variable NewFlag is a variable that signifies whether or not the value of CS has been reduced to a low value corresponding to the second operating state (the second power consumption level that is lower than the first power consumption level).

If the controller42determines at step S43that the variable NewFlag is equal to one (1), then operation moves to the bottom ofFIG. 7and moves to the logic inFIG. 8.

If the controller42determines at step S43that the variable NewFlag is not equal to one (1), then operation moves step S44where the variable NewFlag is made equal to one (1). After step S44, operation moves to step S45where the compressor stroke CS is redefined at a low value of 5 corresponding to the second operating state (the second power consumption level that is lower than the first power consumption level). Hence, the logic in S44and S45reduces the compressor stroke CS to a low value thereby rapidly reducing power load of the compressor30in order to improve acceleration response, rather than waiting for the logic inFIG. 8to reduce the load of the compressor30.

Returning to step S41if the controller42determines that the variable FLG is not equal to one (1), then operation moves to step S46. This indicates that there is no acceleration event or that acceleration is less important than operating the accessories. At step S46the value of the variable TGT is made equal to the variable EVTGT such that control of the power consumption level of the compressor30will be determined based upon cooling needs rather than power consumption needs.

Next at step S47, the variable NewFlag is redefined as being equal to zero (0). Thereafter, operation moves to the logic inFIG. 8.

FIG. 8depicts logic used by the controller42to operate the compressor30and the second power transmitting device40(the de-stroking device of the variable stroke compressor).

At the top ofFIG. 8, the operation has completed the logic presented inFIG. 7and the controller42has determined the value of the variable FLG, as described above with respect toFIG. 5in the first embodiment. Regardless of the value of the variable FLG, the logic shown inFIG. 8can re-define the value of the compressor stroke CS depending upon the values of the variables EVPT and TGT, as described below.

At step S50, the controller42evaluates the temperature EVPT at the evaporator34as measured by the temperatures sensor44. The controller42determines whether or not the measured temperature EVPT is greater than the current value of the target temperature TGT. If the variable EVPT is greater than the target temperature TGT plus Hys (EVPT>(TGT+Hys)), then operation moves to step S51.

At step S51, the controller42redefines the compressor stroke CS upward by the value of the variable Step (CS=CS+Step). This action increases the compressor stroke CS such that a greater amount of refrigerant is compressed, thereby increasing cooling capability.

Returning to step S50, if the controller42determines the variable EVPT is not greater than the target temperature TGT plus Hys (EVPT>(TGT+Hys)), then operation moves to step S52. At step S52, the controller determines whether or not the variable EVPT is less than the target temperature TGT minus Hys (EVPT<(TGT−Hys)). At step S52, if the controller42determines the variable EVPT is less than the target temperature TGT plus Hys (EVPT<(TGT+Hys)), then operation moves to step S53.

At step S53, the controller42redefines the compressor stroke CS downward by the value of the variable Step (CS=CS−Step). This action decreases the compressor stroke CS such that a lesser amount of refrigerant is compressed, thereby decreasing cooling capability and decreasing the amount of power drawn by the compressor30from the power device16.

Next at step S54, the controller42determines whether or not the compressor stroke CS is less than zero (CS<0). If the controller42determines that the compressor stroke CS is less than zero (CS<0), then operation moves to step S55where the value of CS is re-defined as being zero thereby eliminating or completely stopping the compression of refrigerant by the compressor30. Thereafter, operation moves to set S56.

Further, at step S54, if the controller42determines that the compressor stroke CS is not less than zero (CS<0), then operation also moves to step S56.

Returning to step S52, if the controller42determines the variable EVPT is not less than the target temperature TGT minus Hys (EVPT<(TGT−Hys)), then operation moves also to step S56.

Returning to step S51, the controller moves to step S57after the step S51. At step S57, the controller42determines whether or not the compressor stroke CS is greater than 100 (CS>100). If the controller42determines that the compressor stroke CS is greater than 100, then operation moves to step S58where the value of CS is re-defined as being 100 thereby causing the compressor30to operate at full capacity compressing a maximum level refrigerant. Thereafter, operation moves to set S56.

At step S57, if the controller42determines that the compressor stroke CS is not greater than 100, then operation moves to step S56. At step S56, the controller42implements the current value of the compressor stroke CS by setting the compressor30to operate at the set stroke value.

After step S56, operation moves to the logic set forth inFIG. 5for a further iteration of the logic presented in each ofFIGS. 5, 7 and 8.

In the logic presented in the second embodiment, which includesFIGS. 5, 7 and 8, the controller42uses signals from the speed sensor48and the accelerator sensor50to switch a switching part of the second power transmitting device40(and the first power transmitting device28) from the first operating state to the second operating state in response determining that at the current speed of the vehicle10the current level of acceleration requested of the power device16is of greater importance than operating the accessory device at the first operating state. In the second embodiment, the first operating state, the compressor30(a variable stroke compressor) is operated at a first power consumption level where the amount of refrigerant compressed by the compressor30adjusted in response to the cooling needs of the air conditioning system20. In the second operating state, the compressor30is operated by the controller42in a second power consumption level that is lower than the first power consumption level. In the second operating state, the controller42initially reduces the refrigerant compressing capacity of the compressor30(see step S45inFIG. 7) in order to reduce the power consumption level of the compressor30and allow the power device16to achieve the requested acceleration.

Third Embodiment

Referring now toFIGS. 9-16, a power device116in accordance with a third embodiment will now be explained. In view of the similarity between the first and third embodiments, the parts of the third embodiment that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the third embodiment that are identical to the parts of the first embodiment may be omitted for the sake of brevity.

The power device116is basically the same as the power device16described above with respect to the first embodiment, and includes an alternator18and an air conditioning system20with a compressor30. As shown schematically inFIG. 9, the power device116includes an output shaft136, a power transmitting device138attached to the output shaft136, a belt tensioner52and a drive belt24. The power device16is configured to produce rotary power (torque) that powers a drive train (not shown) and propels wheels of the vehicle10. Further, the output shaft136of the power device16provides rotary power to the accessories of the vehicle10, such as the alternator18and the compressor30via the drive belt24.

As shown schematically inFIG. 10, the power device116includes a vehicle accessory power management assembly122includes the controller42, the temperature sensor44, the power sensor46, the speed sensor48and the accelerator sensor50as described above with respect to the first embodiment. The controller42is also connected to the power transmitting device40. The controller42uses data received from selected ones of the temperature sensor44, the power sensor46, the speed sensor48and the accelerator sensor50in order to control operation of the power transmitting device138in a manner consistent with the first embodiment, except that the controller42only controls the state of a single power transmitting device138. In other words as described in greater detail below, in the third embodiment, the power transmitting device138replaces the first and second power transmitting devices28and40of the first embodiment.

The alternator18is accessory device directly supported to or on the power device116and has an input shaft30awith a pulley30bfixed thereto. The drive belt24engages the pulley30bsuch that the alternator18can be provided with rotary power from the power device116.

The compressor30is accessory device directly supported to or on the power device116and has an input shaft32awith a pulley32bfixed thereto. The drive belt24engages the pulley32bsuch that the compressor30can be provided with rotary power from the power device116.

A description of the power transmitting device138in accordance with a third embodiment is now provided with specific reference toFIGS. 11-16. The power transmitting device138has an input part60, an output part62, a speed ratio switching part64and a pulley66. In the first embodiment, the input part60is, for example, a bolt or shaft that is directly coupled to the output shaft136of the power device16directly receiving rotational power therefrom. In other words, the input part60rotates in unison with the output shaft136of the power device16. In the first embodiment, the input part60is fixedly attached to the output shaft136as a threaded mechanical fastener, but can alternatively be unitarily formed with the output shaft136of the power device16or press-fitted to the output shaft136.

The output part62is, for example, a front carrier plate that is secured to the pulley66for rotation therewith. In other words, the output part62and the pulley66rotate in unison at the same speeds. Since the pulley66is engaged by the drive belt24and the drive belt24wraps around the pulley30band the pulley32b, the output part62is directly coupled to the input shaft30aof the alternator18and the input shaft32aof the compressor30via the drive belt24providing rotary power thereto when the power device16is operating.

The speed ratio switching part64includes an electromagnetically actuated clutch68and a sun gear of a planetary gear device70.

As shown removed from the power transmitting device138inFIG. 15, the clutch68basically includes a base member74, an electromagnet76, a clutch plate78and a biasing member80. The base member74is an annular shaped member that includes an annular recess that receives the electromagnet76and, as shown inFIGS. 11 and 12, also includes a central opening74athrough which the input part60extends. The base member74also defines a clutch surface74bthat is shaped and formed to engage the clutch plate78in a conventional manner. The clutch surface74bcan also include an annular concave portion74c, as described in greater detail below.

As shown inFIGS. 11 and 12, the base member74of the clutch68is fixedly attached to the power device116(for example, the clutch68is bolted or otherwise non-movably fixed to an engine block of the power device116). The base member74basically encircles the output shaft136of the power device116with the central opening74abeing aligned with a central axis of the output shaft136. Hence, the base member74of the clutch68is non-movable relative to the power device16. As shown inFIGS. 11 and 12, the clutch plate78is movable between a dis-engaged orientation (FIG. 11) and an engaged orientation (FIG. 12). Specifically, when the controller42causes the electromagnet76to be turned on (to generate an electromagnetic field), the clutch plate78is pulled into engagement with the clutch surface74bof the base member74in a conventional manner. When the controller42causes the electromagnet76to be turned off (no electromagnetic field being generated), the clutch plate78is released and moves into engagement with the planetary gear device70in a manner described further below. The clutch plate78is moved away from the base member74via biasing force of the biasing member80. The biasing member80has a first end with a bearing (not shown) that contacts either the power device16or the output shaft136and a second end in contact with the clutch plate78in a conventional manner. Since electromagnetically controlled clutches, such as the clutch68are conventional structures, further description is omitted for the sake of brevity.

A description of the planetary gear device70is now provided with specific reference toFIGS. 11-12 and 16. The planetary gear device70basically includes a sun gear84, a ring gear86, a planet gear carrier assembly88and planet gears90.

The sun gear84is fixed to the input part60for rotation therewith. For example, the sun gear84can be press-fitted to the shaft of the input part60, or can be provided with a keyway and fastener arrangement. Since the input part60is fixed to the output shaft136of the power device16, the sun gear84, the input part60and the output shaft136of the power device16all rotate together in unison as a single structure.

The ring gear86is an annular shaped member that includes gear teeth along its inner annular surface and a plurality of pins86athat extend through apertures formed in the clutch plate78. The pins86aare rigidly fixed to the ring gear86by, for example, press-fitting engagement. The clutch plate78can move in an axial direction relative to a rotational axis thereof along the pins86a. In other words, the clutch plate78is fixed to the ring gear86for rotation therewith but the clutch plate78can move between the dis-engaged orientation (FIG. 11) and the engaged orientation (FIG. 12) along the pins86arelative to the ring gear86, but cannot rotate relative to the ring gear86. The pins86aextend into the annular concave portion74cof the base member74, but do not contact the base member74. Alternatively, the pins86acan be made shorter so that they do not extend beyond the clutch plate78with the clutch plate78in the engaged orientation (FIG. 5).

The planet gear carrier assembly88basically includes carrier plates92and shafts94. The carrier plates92are connected to one another by the shafts94, which are rigidly fixed therebetween. The planet gears90are installed to the shafts94and rotate freely about the shafts94.

As mentioned above, the clutch plate78and the ring gear86are coupled to one another via the pins86asuch that they rotate together as a single body. The sun gear84is fixed to the input part60such that sun gear84rotates with the output shaft136. The planet gear carrier assembly88is supported within the ring gear86via, for example, bearings and is further supported on the input part60via additional bearings, such that, absent other forces, the planet gear carrier88and planet gears90can rotate within the ring gear86and around the sun gear84. The planet gear carrier88(specifically, one of the carrier plates92) is fixedly attached to the pulley66via the output part62for rotation therewith. In other words, the pulley66, the output part62and the planet gear carrier88all rotate together as a single body. Alternatively, the output part62can be eliminated and the planet gear carrier88directly attached to the pulley66, such that the planet gear carrier88defines the output part62.

Consequently, when the clutch plate78is in the dis-engaged orientation (FIG. 10), the clutch plate78and the ring gear86are free to rotate relative to the power device16. Further the clutch plate78locks the ring gear86to the planet gear carrier88when the clutch plate78is in the dis-engaged orientation (FIG. 11). As a result, the sun gear84and the ring gear86are locked together. Hence, the output shaft136of the power device16and the pulley66rotate at the same speed. With the clutch plate78in the disengaged orientation (FIG. 12), the power transmitting device138operates in a first operating state where the output shaft136of the power device16and the pulley66rotate at the same speed.

When the clutch plate78is in the engaged orientation (FIG. 12) the clutch plate78and the ring gear86are prevented from rotating relative to the power device16. As a result, the sun gear84causes the planet gears90to rotate relative to the ring gear86, which in turn causes the planet gear carrier88to rotate as a rate of speed that is less than the rotation speed of the output shaft136of the power device16. With the clutch plate78in the engaged orientation (FIG. 12), the power transmitting device138operates in a second operating state where the power device16and the pulley66rotate at different speeds.

Consequently, in the first operating state (FIG. 11), the output shaft136of the power device16and the pulley66rotate at the same speed. In the second operating state (FIG. 12) the output shaft136of the power device16and the pulley66rotate at different speeds, with the pulley66rotating at a speed that is less than the output shaft136. In other word, in the second operating state, the planetary gear device70reduces the output speed provided to the pulley66.

The power transmitting device138is switchable between the first operating state in which the input part60and the output part62rotate at a first speed ratio relative to one another and the second operating state in which the input part60and the output part62rotate at a second speed ratio relative to one another. In the depicted embodiment, the first speed ratio is one to on (1:1) and the second speed ratio is such that the output part62rotates at a speed that is lower than the speed of the input part60.

The power transmitting device138(specifically, the speed ratio switching part64) is configured such that the first speed ratio between the input part60and the output part62is such that the input part60and the output part62rotate at the same speed, and the second speed ratio between the input part60and the output part62is such that the output part62rotates at a speed that is between ⅓rdand ⅔rdof the speed of the input part60. In the depicted embodiment, if the electromagnetically actuated clutch68should fail to operate, the power transmitting device138operates in a default mode (i.e. the first speed ratio). However, it should be understood that, alternatively, the power transmitting device138can be re-configured such that the first speed ratio and the second speed ratio can be reversed with the first speed ratio being such that the output part62rotates at a speed that is between ⅓rdand ⅔rdof the speed of the input part60, and in the second speed ratio the input part60and the output part62rotate at the same speed, with the first speed ratio being the default mode.

The controller42operates the power transmitting device138(and in particular the electromagnetically actuated clutch68of the speed ratio switching part64) in the same way the controller42operates the first and second power transmitting devices28and40of the first embodiment. Specifically, all of the operations described above with respect toFIGS. 5 and 6are used by the controller42to operate the power transmitting device138of the third embodiment. Since the logic presented above inFIGS. 5 and 6of the first embodiment applies fully to operation of the power transmitting device138of the third embodiment, further description is omitted to avoid duplication of description and for the sake for brevity.

Additionally, the controller42is also connected to the air conditioning system20and/or the compressor30such that the controller42is configured to switch the speed ratio switching part64between the first operating state and the second operating state in response determining whether the air conditioning system20and/or the compressor30is in operation or not in operation.

Employing the power transmitting device138on the power device116provides the benefit of reducing the torque burden on the power device116caused by operation of the accessory devices, such as the compressor30and the alternator18. During heavy acceleration conditions, such as those represented inFIG. 5, the controller42can reduce the torque burden on the power device116to allow the power device116to devote more power to acceleration when the controller42determines that acceleration is more important than operation of accessories.

Fourth Embodiment

Referring now toFIGS. 17-19, a power transmitting device238in accordance with a fourth embodiment will now be explained. In view of the similarity between the first, third and fourth embodiments, the parts of the fourth embodiment that are identical to the parts of the first and third embodiments will be given the same reference numerals as the parts of the first and/or third embodiments. Moreover, the descriptions of the parts of the fourth embodiment that are identical to the parts of the first and third embodiments may be omitted for the sake of brevity.

In the fourth embodiment, the power transmitting device238is installed within the vehicle10to the power device116in a manner that is the same as the installation of the power transmitting device138of the third embodiment. Since the structure of the vehicle10, the power device116and the accessory devices is unchanged in the fourth embodiment as compared to the third embodiment, description of the vehicle10, the power device116and the accessory devices is omitted for the sake of brevity.

In the fourth embodiment, the power transmitting device238includes an electromagnetically actuated clutch168and a differential gear device170. The electromagnetically actuated clutch168includes the base member74as described above in the third embodiment, and a clutch plate178. The base member74, as in the third embodiment, is non-movably fixed to the power device116(for example, directly attached to the engine block of the power device116). The operation of the electromagnetically actuated clutch168is identical to the electromagnetically actuated clutch68of the third embodiment. Therefore, further description of the electromagnetically actuated clutch168is omitted for the sake of brevity.

The differential gear device170includes a first gears186aand186b, second gears188, a carrier shaft189and a carrier190. The first gear186ais a driven gear that is rigidly fixed to the output part60. As with the third embodiment, the output part60is fixed to the output shaft136of the power device116such that the output shaft136of the power device116, the output part60and the first gear186aall rotate together as a single body. The second gears188rotate about the carrier shaft189. The carrier shaft189is supported by the carrier190. The carrier190is fixed to the pulley66such that the carrier190, the carrier shaft189and the pulley66all rotate together as a single body.

The first gear186bis fixed to a carrier plate192that includes pins192aand a central apertures192b. When the differential gear device170is fully assembled, the input part60extends through the central aperture192bof the carrier plate192and extends through a central apertures178aof the clutch plate178. However, the carrier plate192and the clutch plate178are rotatable relative to the input part60absent operation of the electromagnetically actuated clutch168.

The pins192aof the carrier plate192extend through apertures178bof the clutch plate178. Consequently, the clutch plate178, the carrier plate192and the first gear186ball rotate together as a single body.

As shown inFIG. 17with the electromagnetically actuated clutch168in the dis-engaged orientation, the clutch plate178engages the pulley66and the carrier190such that the carrier190, the carrier plate192the pulley66and the clutch plate178all rotate together as a single body thereby operating in the first operating state.

As shown inFIG. 18with the electromagnetically actuated clutch168in the engaged orientation, the clutch plate178engages the base member74such that the clutch plate178and the carrier plate192and the first gear186bare prevented from rotating, there by operating in the second operating state. In the second operating state, the first gear186ais rotated by the input part60, causing rotation of the second gears188. Since the first gear186bis prevented from rotating, the rotation of the second gears188causes the carrier190and the pulley66to rotate at a rate of speed that is less than the rotational speed of the input part60.

The controller42operates the power transmitting device238in the same way the controller42operates the first and second power transmitting devices28and40of the first embodiment (and the power transmitting device138of the third embodiment). Specifically, all of the operations described above with respect toFIGS. 5 and 6are used by the controller42to operate the power transmitting device238of the fourth embodiment. Since the logic presented above inFIGS. 5 and 6of the first embodiment applies fully to operation of the power transmitting device238of the fourth embodiment, further description is omitted to avoid duplication of description and for the sake for brevity.

The structure of the power transmitting devices138and238of the third and fourth embodiments is described in greater detail in U.S. patent application Ser. No. 14/973,292, filed Dec. 17, 2015. U.S. patent application Ser. No. 14/973,292 discloses control logic that differs from the above described control logic. U.S. patent application Ser. No. 14/973,292 is commonly assigned to Nissan North America, Inc. and as a common sole inventor. U.S. patent application Ser. No. 14/973,292 is incorporated herein by reference in its entirety.

Fifth Embodiment

Referring now toFIGS. 20-21, control logic for the controller42in accordance with a fifth embodiment will now be explained. In view of the similarity between the first and fifth embodiments, the parts of the fifth embodiment that are identical to the parts of the first embodiment will be given the same reference numerals as the parts of the first embodiment. Moreover, the descriptions of the parts of the fifth embodiment that are identical to the parts of the first embodiment may be omitted for the sake of brevity.

In the first embodiment,FIG. 5shows an example of logic used to determine which is of greater importance: vehicle acceleration; or accessory operation. The data and logic depicted inFIGS. 20 and 21is another example of logic for determining whether vehicle acceleration is of greater importance, or whether vehicle accessory operation is of greater importance at the current vehicle speed and level of requested acceleration. The logic presented inFIGS. 20 and 21represents an example of an alternative to the logic represented inFIG. 5. In other words, the logic presented inFIGS. 20 and 21can replaceFIG. 5in the first embodiment, and used with the logic inFIG. 6. Specifically, the logic represented inFIGS. 20 and 21is used withFIG. 6by the controller42in this fifth embodiment.

A further embodiment can be utilized based on the second embodiment. Specifically, the logic inFIGS. 20 and 21can be used by the controller42with the logic presented inFIGS. 7 and 8.

A description is now provided for the logic represented inFIGS. 20 and 21.FIG. 20is a graph showing accelerator position measurements (X-axis) and vehicle speed measurements S (Y-axis). The point P1represents a minimum level of acceleration requested (determined by measuring movement of the accelerator pedal or movement of the throttle body linkage of the power plant). In order for acceleration to be considered of greater importance than accessory operation, the accelerator sensor50must detect a requested level of acceleration greater than that at the point P1. The value of the point P1differs in model to model (vehicle to vehicle). For example, in a vehicle with a large capacity power device16where accessory loads represent a relatively small load of the overall power output of the power device16, the value of the point P1will be much greater than the values of the point P1in vehicle with a small capacity power device16where accessory loads represent a much larger percentage of the overall output of the power device16.

The slope of the line L1also differs from model to model (vehicle to vehicle) depending upon the size of the vehicle10, the overall power output of the power device16and the amount of power necessary to operate the accessories. Therefore, no specific values are applied, except that along the X-axis, the point100represents 100% acceleration being requested. In other words, 100% represents the accelerator pedal (not shown) being measured at a maximum, for example, where the accelerator pedal is pressed completely to the floor of the vehicle10.

Hence, when the controller42determines that a pair of coordinates corresponding to current accelerator position and current vehicle speed lie at a point below the line L1inFIG. 20, acceleration is of greater importance than accessory operation. Further, when the controller42determines that a pair of coordinates corresponding to current accelerator position and current vehicle speed lie at a point above or on the line L1inFIG. 20, accessory operation is of greater importance than acceleration.

InFIG. 21at step S60, the controller42determines the location of a pair of coordinates corresponding to current accelerator position and current vehicle speed, as measured by the accelerator sensor50and the speed sensor48, respectively. If the pair of coordinates lies above the line L1, then operation moves to step S61. If the pair of coordinates lies below the line L1, then operation moves to step S62. At step S61, the variable FLG is made equal to zero. At step S62FLG is made equal to 1. After each of steps S61and S62, operation moves to the logic inFIG. 6(first embodiment) or toFIG. 7(second embodiment).

The controller42preferably includes a microcomputer with a power transmitting device control program that controls the power transmitting devices28,40,138and238, as discussed below. The controller42can also include other conventional components such as an input interface circuit, an output interface circuit, and storage devices such as a ROM (Read Only Memory) device and a RAM (Random Access Memory) device. The microcomputer of the controller42is programmed to control the power transmitting device238. The controller42is operatively coupled to the various parts of the vehicle10as describe above in a conventional manner. The internal RAM of the controller42stores statuses of operational flags and various control data. It will be apparent to those skilled in the art from this disclosure that the precise structure and algorithms for the controller42can be any combination of hardware and software that will carry out the functions of the present invention.

The various vehicle elements and accessory devices are conventional components that are well known in the art. Since such elements and devices are well known in the art, these structures will not be discussed or illustrated in detail herein. Rather, it will be apparent to those skilled in the art from this disclosure that the components can be any type of structure and/or programming that can be used to carry out the present invention.

General Interpretation of Terms

The term “detect” as used herein to describe an operation or function carried out by a component, a section, a device or the like includes a component, a section, a device or the like that does not require physical detection, but rather includes determining, measuring, modeling, predicting or computing or the like to carry out the operation or function.