Abstract:
A drive system includes a drive belt, an engine, a motor, and a supercharger for delivering compressed air to an intake of the engine, and a controller for setting the operational mode of the drive system. The engine and motor are selectively engageable with the drive belt, and the supercharger is selectively engageable with the motor. A method of controlling an operational mode of such a drive system includes detecting a throttle position. Thereafter, the method includes selectively engaging the engine with the drive belt or the drive belt with the motor or the motor with the supercharger, based at least in part on the throttle position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation Application of PCT/US2013/057346 filed on Aug. 29, 2013, which claims benefit of U.S. Patent Application Ser. No. 61/701,071 filed on Sep. 14, 2012, and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     
    
     INTRODUCTION 
       [0002]    Superchargers are used to pressurize air delivered to the intake of an internal combustion engine to increase the engine&#39;s power output. Typically, a supercharger is powered mechanically by a belt or chain drive from the engine crankshaft. For this reason, performance of a supercharger is dependent on engine RPM. It may be less desirable to operate a supercharger if, for example, if the engine is operating at a high RPM while under a low load, or at a low RPM under a high load. In such cases, use of the supercharger may be a drain on the engine efficiency. Other drains on an engine&#39;s efficiency may be caused by powering of a motor/generator of a hybrid engine system, as well as powering other vehicle accessories. 
       SUMMARY 
       [0003]    In one aspect, the technology relates to a drive system for a vehicle, the drive system including: a drive belt; an engine selectively engageable with the drive belt; a motor selectively engageable with the drive belt; a supercharger for delivering compressed air to an intake of the engine, wherein the supercharger is selectively engageable with the motor; and a controller for setting an operational mode of the drive system, wherein when in a power mode, the controller engages the engine with the drive belt, the controller engages the supercharger with the motor so as to deliver compressed air from the supercharger to the intake of the engine, and the controller disengages the motor from the drive belt; and wherein when in a cruise mode, the controller disengages the engine from the drive belt, the controller engages the supercharger with the motor so as to deliver compressed air from the supercharger to the intake of the engine, and the controller engages the motor with the drive belt. 
         [0004]    In another aspect, the technology relates to a method of setting an operational mode of a drive system including a drive belt, an engine, a motor, and a supercharger for delivering compressed air to an intake of the engine, and a controller for setting the operational mode of the drive system, the method including: wherein when in a power mode, the controller engages the engine with the drive belt, the controller engages the supercharger with the motor so as to deliver compressed air from the supercharger to the intake of the engine, and the controller disengages the motor from the drive belt; wherein when in a cruise mode, the controller disengages the engine from the drive belt, the controller engages the supercharger with the motor so as to deliver compressed air from the supercharger to the intake of the engine, and the controller engages the motor with the drive belt; wherein when in a regeneration mode, the controller engages the engine with the drive belt, the controller disengages the supercharger from the motor, and the controller engages the motor with the drive belt; and wherein when in an engine-off mode, the controller disengages the motor from the drive belt, the controller disengages the supercharger from the motor, and the controller disengages the supercharger from the motor. 
         [0005]    A method of setting an operational mode of a drive system including a drive belt, an engine, a motor, and a supercharger for delivering compressed air to an intake of the engine, and a controller for setting the operational mode of the drive system, the method including: detecting a throttle position; and selectively engaging at least one the engine with the drive belt, the drive belt with the motor, and the motor with the supercharger, based at least in part on the throttle position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    There are shown in the drawings, embodiments which are presently preferred, it being understood, however, that the technology is not limited to the precise arrangements and instrumentalities shown. 
           [0007]      FIG. 1  depicts a vehicle drive system. 
           [0008]      FIG. 2A  depicts a vehicle drive system in a default mode. 
           [0009]      FIG. 2B  depicts a vehicle drive system in a power mode. 
           [0010]      FIG. 2C  depicts a vehicle drive system in a cruise mode. 
           [0011]      FIG. 2D  depicts a vehicle drive system in a regeneration mode. 
           [0012]      FIG. 2E  depicts a vehicle drive system in an engine-off mode. 
           [0013]      FIG. 3  depicts a logic control routine for a vehicle drive system. 
           [0014]      FIG. 3A  depicts an engine-off subroutine of the logic control diagram of  FIG. 3 . 
           [0015]      FIG. 3B  depicts a regeneration subroutine of the logic control diagram of  FIG. 3 . 
           [0016]      FIG. 3C  depicts a cruise subroutine of the logic control diagram of  FIG. 3 . 
           [0017]      FIG. 3D  depicts a power subroutine of the logic control diagram of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Reference will now be made in detail to the exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure. 
         [0019]    The technology provides a number of controlled clutches or coupling devices at various components of a vehicle. By coupling and de-coupling selected components from each other during various states of operation, the components may be operated independent of engine rpm, resulting in more efficient operation of the engine, improved performance, and continued operation of certain accessories after vehicle shut down, as desired. 
         [0020]      FIG. 1  depicts a vehicle drive system  100  including an engine  102  and a number of related components. The engine  102  is connected to a transmission  102   a  that rotates a drive shaft or axle  104  that, in turn, drives a transaxle  106  and a number of drive wheels  108 . The engine  102  is aspirated by a supercharger  110  that includes an air intake  112  and an air discharge  114  into the engine  102 . Various types of superchargers are known and the operation and advantages thereof are readily apparent to a person of skill in the art. In the systems and vehicles described herein, virtually any type of supercharger, including roots, twin-screw, sliding vane, and scroll, may be utilized. The supercharger  110  is powered by a hybrid electric motor/generator  116 . Operational power from the motor/generator  116  to the supercharger  110  is depicted as being transferred by a supercharger belt  118 , which may be selectively engaged by the motor/generator  116  with a supercharger clutch  120 . The supercharger belt  118  is but one type of power transfer element that may be utilized in the systems depicted herein. In other embodiments, direct drive connections utilizing a selectively engageable clutch may be used. 
         [0021]    The motor/generator  116  is also selectively engageable with a drive belt  122  via a motor clutch  124 . The drive belt  122  also provides power for one or more vehicle accessories  126 , which may include one or more of an air conditioning compressor, an engine coolant pump, an alternator, a power steering pump, and a brake air compressor. Rotation of the drive belt  122  is provided by the engine  102  in certain operational modes. The engine  102  may be selectively engageable with the drive belt  122  via an engine clutch  128 . Returning to the motor/generator  116 , a DC-to-AC inverter  130  connects that element to a high voltage power supply/storage element, such as a battery  132  or other energy storage device, such as a super capacitor. 
         [0022]    A number of the elements identified above are connected via various sensors to a vehicle CPU  134 . For example, sensors may be associated with the engine  102 , the transmission  102   a,  the axle  104 , the accessories  124 , the motor  116 , the supercharger  110 , the inverter  130 , and the battery  132 . Any type of sensor typically used to deliver signals to a vehicle CPU may be utilized with the depicted system  100 . Sensors that detect conditions such as requested torque, throttle position, battery state-of-charge, vehicle speed, accessory need condition, airflow rate, temperature, axle rotational speed, available engine torque, catalyst state, grade (i.e., uphill or downhill), etc., may be utilized. Indeed, any sensors may be used in conjunction with any given component of a vehicle, including, but not limited to engine transmission, anti-lock brake system control, power electronics, etc. At least one benefit of the drive system  100  described herein is that existing components, such as superchargers, accessories, batteries, etc., may be used therewith, without requiring redesign of those components. This makes the system  100  extremely simple to incorporate into new vehicle designs or to enhance existing vehicles. A CPU  134  receives signals from the various sensors, determines the operational state of the vehicle and requirements of any components, and actuates the clutches  120 ,  124 ,  128  as required or desired for a particular application. The CPU  134  may perform any number of calculations, or process any number of signals, to make its mode selection. Of course, control signals may be sent from the CPU  134  to associated clutch actuators (not shown). The processes utilized by the CPU  134  to control the drive system  100  are described below. 
         [0023]      FIGS. 2A-2E  depict a vehicle drive system  200  in various operational modes. Select components previously introduced in  FIG. 1  are depicted. The presence of other components (e.g., a CPU, sensors, etc.) in the system  200  would be apparent to a person of skill in the art. The depicted components include an engine  202 , a drive shaft or axle  204 , a drive belt  222 , an electrical accessory  226 , a motor/generator  216 , and a supercharger  210  having an air intake  212  and an air discharge  214 . Additionally, an engine clutch  228 , a motor clutch  224 , and a supercharger clutch  220  are also depicted. Additional elements include an engine pulley  250 , an accessory pulley  252 , a motor pulley  254 , and a supercharger drive  256 . As described previously, a belt system may be used to drive the supercharger  210 . The operational mode of the system  200  is determined by the CPU (not shown), which engages and/or disengages the various clutches  220 ,  224 ,  228  as required or desired.  FIG. 2A  depicts the system  200  in a default mode. Relevant to the default mode, each of the engine clutch  228 , the motor clutch  224 , and the supercharger clutch  220  are engaged with the engine pulley  250 , the motor pulley  254 , and the supercharger drive  256 , respectively. In the default mode, the engine  202  provides power to all of the accessories  226 , motor  216 , and supercharger  210 , via the drive belt  222 . Here, the supercharger  210  delivers compressed air  260  to the engine  202 , based on the engine RPM. Under certain circumstances it may be more efficient to operate the vehicle drive system  300  in the default mode. Additionally, if a system fault is present that would prevent operation of the vehicle in a different mode, the vehicle will still be operational. This allows the operator to control the vehicle until the system  200  can be serviced and any issues corrected. 
         [0024]      FIG. 2B  depicts the system  200  in a power mode. In the power mode, the engine clutch  228  is engaged with the engine pulley  250 , the motor clutch  224  is disengaged from the motor pulley  254 , and the supercharger clutch  228  is engaged with the supercharger drive  256 . In the power mode, the supercharger  210  may be driven at a desired rate by the motor  216 , instead of the mechanical rate delivered by the engine  202 , in order to deliver compressed air  260  to the engine  202 . This allows torque to be developed faster due to pressurization of the engine air intake by the supercharger  210 . Since the supercharger  210  is powered by the motor  216 , pressurization is not delayed, which is the case with a supercharger powered by an engine. The power required by the motor  216  to drive the supercharger  210  is provided by the battery (not shown). Power to the vehicle accessories  226  is provided by the engine  202 , via the drive belt  222 . 
         [0025]      FIG. 2C  depicts the system  200  in a cruise mode. In the cruise mode, the engine clutch  228  is disengaged from the engine pulley  250 , the motor clutch  224  is engaged with the motor pulley  254 , and the supercharger clutch  220  is engaged with the supercharger drive  256 . This mode allows a reduction in parasitic losses by allowing the engine  202  to run at a speed independent of the needs of the supercharger  210  and accessories  226 . Electrical power from the battery (not shown) to the motor  216  drives both the accessories  226  (via the drive belt  222 ) and the supercharger  210  (to deliver compressed air  260  to the engine  202 ). 
         [0026]      FIG. 2D  depicts the system  200  in a regeneration mode. In the regeneration mode, the engine clutch  228  is engaged with the engine pulley  250 , the motor clutch  224  is engaged with the motor pulley  254 , and the supercharger clutch  220  is disengaged from the supercharger drive  256 . Accordingly, the supercharger  210  is not operational and no compressed air is delivered to the engine  202 . However, the engine power delivered to the motor  216  via the drive belt  222  is converted into electrical power and stored at the battery (not shown). Engine power also drives the accessories  226 .  FIG. 2E  depicts the system  200  in an engine-off mode, which typically occurs at vehicle stop or idle. In the engine-off mode, the engine clutch  228  is disengaged from the engine pulley  250 , the motor clutch  224  is engaged with the motor pulley  254 , and the supercharger clutch  220  is disengaged from the supercharger drive  256 . This mode allows accessories  226 , such as vehicle air conditioning, alternator, power steering, etc., to continue to run in the absence of power from the engine  202 . Since the engine  202  is not operational in this mode, compressed air need not be delivered by the supercharger  210 . Accordingly, disengaging the supercharger  210  helps reduce electrical load on the motor  216 . Power is provided to the motor  216  by the battery (not shown). 
         [0027]    In other embodiments, to further reduce engine or motor load, an accessory clutch may be selectively engageable with the accessory pulley  254 . In such an embodiment, a “need” condition may be sent to the CPU from the accessory  226 , indicating power to the accessory  226  is needed. In the absence of a need condition, the accessory pulley  252  may be disengaged from the accessory clutch. 
         [0028]    This would also reduce engine or motor load in other operational modes. Other embodiments may reduce motor load by shutting down the motor  216  when no need condition is present, regardless of whether or not the accessory clutch is selectively engageable with the accessory pulley  254 . If the system  200  is in the engine-off mode and there is no need condition present, the motor  216  may cease delivering mechanical power to the belt  222 . 
         [0029]      FIG. 3  depicts a logic control routine  300  for a vehicle drive system. The initial operational mode of the vehicle is a DEFAULT mode  302 . As described briefly above, when in the DEFAULT mode  302 , the vehicle is operational in a basic state. In the DEFAULT mode, the engine provides operational power to all of the accessories, the motor/generator, and the supercharger. Once in the initial DEFAULT mode  302 , the routine  300  first performs checks to determine if any system faults are present  304 . This review of system conditions to determine faults is enabled to ensure that the vehicle drive system may effectively be changed from the DEFAULT mode  302  to one of the other operational modes. The presence of any system faults will compel the routine  300  to revert back to the DEFAULT mode  302 . In fact, it may be desirable to monitor for system faults on a continuous loop during operation of the vehicle. Accordingly, any number of system faults that are identified at any time during vehicle operation may cause the routine  300  to return to the DEFAULT mode  302 . These system faults may include an anti-lock brake system event (that is, the vehicle has entered a skid requiring traction control). In such a case, it may be desirable to revert to the DEFAULT mode to avoid, e.g., an over-engine brake condition in a REGENERATION mode, or an over-power condition in a POWER mode. Additional system faults may include engine temperatures in excess of a particular threshold, inadequate air conditioning compressor pressure, out-of-range or failure signals from a sensor, etc. 
         [0030]    If no system faults are present, the routine  300  next determines if an engine-off request has been made  306 . The routine  300  may determine that an engine-off request has been made by considering, e.g., vehicle speed and throttle position. A throttle OFF position coupled with a vehicle speed of zero MPH may, in certain embodiments, be considered an engine-off request. Other factors to consider would be apparent to a person of skill in the art. If such a request has been made, an engine-off subroutine is entered  308 . If such a request has not been made, the routine  300  next determines an engine throttle position  310 . If the throttle is in an 
         [0031]    OFF position, a regeneration subroutine is entered  312 . If the throttle is in a LOW RANGE position, a cruise subroutine is entered  314 . If the throttle position is in a HIGH RANGE position, a power subroutine is entered  316 . The LOW and HIGH ranges may be defined as required or desired for a particular application. For example, in the medium-duty truck category (for example, box trucks having vehicle weights of about 10,000 to about 50,000 lbs.), it has been determined that the low range may be greater than about 0% (i.e., the off position) up to about 69%. The high range may include throttle positions greater than about 69% and up to 100% open. Other ranges are contemplated and would be apparent to a person of skill in the art. Of course, as the vehicle system is set in a particular mode, the controller engages or disengages the various clutches, as described above. 
         [0032]      FIG. 3A  depicts the engine-off subroutine  308 . Upon entering  318  the engine-off subroutine  308 , a system fault check  320  is performed. This system fault check  320  may be similar to the system fault check  304  described above with regard to  FIG. 3 . Indeed, the vehicle system may be constantly monitored for the presence of system faults. The existence thereof reverts the vehicle drive system to the DEFAULT mode  302 . If no system faults are present, the engine-off subroutine  308  next determines if the battery state-of-charge is greater than a minimum threshold  322 . If the state of charge is not above a minimum threshold, the drive system reverts to the DEFAULT mode  302 , so as to prevent further power drain from the battery. If the state-of-charge is above the minimum threshold, the drive system enters the ENGINE-OFF mode  324 . The threshold may be set as required or desired for a particular application and, for example, may contemplate storing a minimum amount of battery charge at all times. Alternatively, the minimum threshold may be no charge. Acceptable thresholds may be based on issues related to battery technology or type, desired battery life, battery capacities or temperature thresholds, motor conditions, inverter conditions, etc. Of course, other factors may be considered in making the determination if the vehicle system should be set in ENGINE-OFF mode  324 . For example, the controller may query a sensor associated with the drive wheels to determine if the wheels are rotating (thus indicating that the vehicle is moving and not at stop). Other factors are contemplated and would be apparent of a person of skill in the art. 
         [0033]      FIG. 3B  depicts the regeneration subroutine  312 . Upon entering  326  the regeneration subroutine  312 , a system fault check  328  is performed. This system fault check  328  may be similar to the system fault checks described above. The existence of a system fault reverts the vehicle drive system to the DEFAULT mode  302 . If no system faults are present, the regeneration subroutine  312  next determines if the vehicle speed is above a minimum speed  330 . If not, the drive system reverts to the DEFAULT mode  302 . If so, the regeneration subroutine  312  determines if the battery state-of-charge is below a maximum threshold  322 . If not, the drive system reverts to the DEFAULT mode  302 . Alternatively, the drive system is set to the REGENERATION mode  334 . In general, in most circumstances where the vehicle is moving and the battery state of charge is less than a determined maximum for the battery, the drive system will be set to the REGENERATION mode  334 , thus enabling vehicle kinetic energy to be recaptured as electrical power and stored in the battery. 
         [0034]      FIG. 3C  depicts the cruise subroutine  314 . Upon entering  336  the cruise subroutine  312 , a system fault check  338  is performed. This system fault check  338  may be similar to the system fault checks described above. The existence of a system fault reverts the vehicle drive system to the DEFAULT mode  302 . If no system faults are present, the cruise subroutine  314  next determines if the battery state-of-charge is greater than a minimum threshold  340 . If not, the vehicle drive system reverts to the DEFAULT mode  302 . If so, the cruise subroutine  314  next determines if the vehicle speed is above a minimum speed  342 . If not, the vehicle drive system reverts to the DEFAULT mode  302 . If so, the cruise subroutine  314  next determines if the engine RPM and load are within target thresholds  344 . If not, the vehicle drive system reverts to the DEFAULT mode  302 . If so, the drive system is set in CRUISE mode  346 . In general, CRUISE mode  346  is set whenever the vehicle is moving, but where additional power is not required due to load requirements or acceleration. Of course, CRUISE mode may be set under any other circumstances where the system has determined that the engine speed is higher than needed for efficient accessory operation. 
         [0035]      FIG. 3D  depicts the power subroutine  316 . Upon entering  348  the power subroutine  316 , a system fault check  350  is performed. This system fault check  350  may be similar to the system fault checks described above. The existence of a system fault reverts the vehicle drive system to the DEFAULT mode  302 . If no system faults are present, the power subroutine  316  next determines if the battery state of charge is greater than a minimum threshold  352 . If not, the vehicle drive system reverts to the DEFAULT mode  302 . If so, the power subroutine  316  next determines if the vehicle speed is below a maximum speed  354 . If not, the vehicle drive system reverts to the DEFAULT mode  302 . If so, the drive system is set in POWER mode  356 . In general, POWER mode  356  is set whenever the vehicle is moving, but where additional power is required due to load requirements or acceleration. This power can then be delivered regardless of engine RPM. 
         [0036]    The controller or CPU may be an on-board vehicle computer that monitors and controls various engine components, issues warnings, etc. The CPU is loaded with the necessary software or firmware required for use of the system. In alternative configurations, software may be included on various types of storage media (CDs, DVDs, USB drives, etc.) for upload to a vehicle computer. Additionally, website addresses and passwords may be included for programs to be downloaded from a website on the internet. 
         [0037]    The control algorithm technology described herein can be realized in hardware, software, or a combination of hardware and software. The technology described herein can be realized in a centralized fashion in one computer system or in a distributed fashion where different elements are spread across several interconnected computer systems. Additionally, the control system may be incorporated into the vehicle&#39;s main computer system. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suitable. A typical combination of hardware and software would be stand-alone device integrated into the engine control system that, when loaded and executed, controls the device such that it carries out the methods described herein. Since the technology is contemplated to be used on vehicles, a stand-alone hardware system including any necessary operator interfaces (system power, override, etc.) may be desirable. Diagnostic or maintenance functions may be loaded onto a separate PC, either stationary at a repair facility or on a laptop or other portable device. This would allow for trouble shooting and repair of potentially faulty vehicle drive systems, or the components utilized therewith. 
         [0038]    The technology described herein also can be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form. 
         [0039]    While there have been described herein what are to be considered exemplary and preferred embodiments of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.