DE60118987T2 - HYDRAULIC ENERGY STORAGE SYSTEMS - Google Patents

Description

Background of the invention

(i) Field of the invention

These The invention relates to hydraulic energy storage systems and more particularly hydraulic energy storage systems used in vehicles to a higher one Effectiveness, a smaller space consumption, a lower weight, a uniform structure, consistency and increased reliability to provide while maintain the ability is going to save energy at high power levels and effectively to give up again.

(ii) description of related technique

With equipped with hydraulic energy storage systems have the ability to to store kinetic energy when braking instead of using it to dissipate the brakes, and then for a subsequent acceleration to insert again. Such vehicles are commonly referred to as "hydraulic hybrid" when the main winder of the vehicle also to the energy storage contributes or as "Stored Hydraulic Energy Propulsion "(SHEP), if only the vehicle energy is stored. This application relates on SHEP storage, but the inventions disclosed herein can equally for hydraulic hybrid vehicles be applicable.

The Improvements of the present invention are to hydro-pneumatic Memory applicable, usually used for energy storage in SHEP vehicles Hydraulic hybrid and the associated Hydraulic circuit. In accordance with industrial practice, the term "fluid" refers to as in this application used on a hydraulic fluid, typically a liquid like a specially prepared mineral oil. The term "gas" refers to the gas used to precharge a hydropneumatic accumulator is, and is typically dry nitrogen.

The capacity and the fuel economy of a vehicle, especially when it is frequent Stops and starts can be improved by the recovered kinetic energy of the vehicle during braking and is stored and then during a subsequent acceleration less losses occurring is used again. SHEP systems have a hydraulic pump / motor device (P / M) on, which may be connected to a drive train of the vehicle, so that Vehicle can be braked by a high pressure hydraulic fluid is pumped into a hydro-pneumatic accumulator and thereby the kinetic energy of the vehicle is recovered. A subsequent one Acceleration can be at least partially saved by using the kinetic energy can be achieved to the P / M device as to drive a motor. Hydraulic hybrid systems have this same ability on, with the addition of a driven by the vehicle engine hydraulic pump. This puts at the expense of increased complexity a more flexible system. Importantly, it provides for more Improvements in fuel consumption by a optimized engine use.

Hydraulic hybrid and SHEP vehicles are the subject of many patents and technical writings. US Patent No. 3,903,696 shows a basic SHEP system, US Patent No. 4,760,697 showing a more complex version, and US Patent No. 4,242,922 describing the basics of a hydraulic hybrid. US 2,721,446 discloses a system using compensated accumulator with high and low pressure chambers with pistons connected in a pump hydraulic system. DE-A-42 12 542 discloses a system having the features of the preamble of claim 1.

Published technical writings involving the use of SHEP and hybrid systems in automobiles, buses, garbage trucks, Trains or others Covering vehicles are typically through the following writings given: Mechanical power regeneration system; "Simulation of a Hydraulic Hybrid Vehicle Power Train ", ASME paper n 73-ICT-50, Sep. 23, 1973; "Practical Considerations for Energy-Storage Motor Vehicles ", published by ASME, New York, N.Y., U.S.A. 1981; and "Studies of an Accumulator Energy Storage Automobile Design with a Single Pump / Motor Unit ", SAE Paper 851677 1985th

Summary the invention

According to the present invention, there is provided a hydraulic energy storage system for use in a vehicle, comprising a high pressure accumulator, a first low pressure accumulator and in parallel a second low pressure accumulator and pump / motor means in fluid communication with the high pressure accumulator and with the first and second low pressure accumulators Pumping fluid from the first and second low pressure accumulator to the high pressure accumulator when the pump / motor means is operated in a pumping mode, and to return fluid to the first and second low pressure accumulator when the pump / motor means is in an engine mode, the pump / motor means a housing to circulate through this fluid reindeer,
characterized in that the system further includes in series between the pump / motor means and the second low pressure accumulator a first check valve for, when the pump / motor means is in the engine mode, flowing a fluid portion in a direction from the pump / motor means to the second low pressure accumulator in series between the pump / motor housing, the second low pressure accumulator and the pump / motor means has a radiator in flow communication and in series between the second low pressure accumulator and the pump / motor housing has a second check valve to Motor means in the pumping mode is to flow fluid in a direction from the second low pressure accumulator through the pump / motor housing housing and the radiator to the pump / motor means to cool that portion of the fluid.

Advantageous the system continues in series between the pump / motor device, the pump housing and the radiator a third check valve to when the pump / motor is in the engine mode, a proportion of fluid in one direction from the pump / motor means through the pump housing and the radiator flow to let go, with the first check valve with the radiator in series is a proportion of fluid in a direction from the radiator to flow to the second low-pressure accumulator to this fluid content to cool, taking the system continues in series with the radiator a fourth check valve to when the pump / motor device in the pumping mode is a fluid portion in one direction from the second low-pressure accumulator to the pump / motor housing and through the radiator the pump / motor device to flow to this fluid content to cool.

The System can one the high pressure accumulator and first low pressure accumulator comprising compensated memory, wherein the compensated Memory a cylindrical housing with a longitudinal axis and with a high pressure chamber and a low pressure chamber concentric with the longitudinal Axis are located, a transversal mounted in the high pressure chamber High pressure piston for a mutual axial stroke in the high pressure chamber and a transversal Low pressure piston mounted in the low pressure chamber for reciprocal axial stroke in the low-pressure chamber and at least one connecting rod to the high-pressure piston and the low-pressure piston with each other connect to. The compensated memory can be at least three equal spaced rods having the high pressure piston with the Connect low pressure pistons to the pistons during the reciprocal stroke perpendicular to the longitudinal axis of the cylindrical housing hold. The low pressure chamber may be one remote from the high pressure chamber Have gas end and a fluid end located near the high pressure chamber, wherein a first position sensor in the low pressure chamber near the low pressure end is attached, and a second position sensor in the low-pressure chamber mounted near the high pressure end, whereby the first and second Position sensor the mutual stroke of the low pressure piston in the Monitor low pressure chamber. The system can additionally having a pressure sensor in fluid communication with the high pressure chamber, wherein the second position sensor or the pressure sensor is the reciprocal Hub of high pressure and low pressure piston monitors and a heating system actuated. The gas end may have an end wall, and the first position sensor be mounted in the end wall. The first position sensor can be found in the End wall at height be mounted on the longitudinal axis and have a supersonic transducer.

Advantageous the compensated accumulator has a valve block at one end of the cylinder housing, a high pressure fluid end connecting to the valve block high pressure line and one connecting the low pressure fluid end to the valve block Low pressure line on. The high pressure and low pressure lines can outside of the cylindrical housing run. Alternatively you can the high pressure and low pressure lines within the cylindrical housing be arranged parallel to the longitudinal axis and through the Low pressure piston run, with an additional in the low-pressure piston formed sealing device is provided to sliding on high pressure and low pressure lines to couple and seal this.

One chamber of high pressure chamber and low pressure chamber may have a larger diameter than the other, wherein a piston of high pressure piston and low pressure piston has a larger diameter than the other to cause a flux imbalance between the high pressure cylinder and the low pressure cylinder, wherein the pump motor means in fluid communication with the high pressure chamber and the low pressure chamber is to pump fluid from the low pressure chamber to the high pressure chamber when the pump motor device is operated in a pumping mode and to return fluid to the low pressure chamber when the pump / motor device is operated in a motor mode, wherein a low pressure accumulator is arranged in parallel with the low pressure chamber to a Fuidanteil of the high pressure or low pressure chamber to it during the pumping mode or the engine mode due to the flux imbalance between the high pressure cylinder and the low pressure cylinder hold and deliver. The high pressure piston may be larger than the low pressure piston, whereby the exclusion from the high pressure chamber is greater than the influence in the low pressure chamber to maintain a high fluid pressure and to create a positive flow imbalance from the high pressure cylinder to the low pressure cylinder. The low pressure accumulator may be an annular chamber concentrically formed within the low pressure chamber and having an annular accumulator piston mounted for reciprocal lift in the annular accumulator chamber. The annular accumulator piston may be an elongated annular hoop.

The System can be a low-pressure chamber storage cylinder, the central in the low pressure chamber concentric with and within the low pressure ring piston is formed, and one between the low pressure storage cylinder and the annular piston formed sealing means, whereby the ring piston in sliding coupling with the low-pressure accumulator piston is, wherein the pump / motor means in fluid communication with the High pressure chamber and with the low pressure chamber and the low pressure accumulator is to a fluid from the low pressure chamber and the low pressure accumulator to pump to the high pressure chamber when the pump / motor device in a pumping mode, and fluid from the high pressure chamber the low pressure chamber and return to the low pressure reservoir, when the pump / motor device is in a motor mode, wherein the cooler is in fluid communication with the low pressure accumulator, whereby the to the low pressure accumulator and away from flowing fluid through the radiator flows, if the pump / motor device is in the pump or motor mode. Of the Low-pressure storage cylinder can be formed in its upper region access opening to release air into the atmosphere. The high pressure chamber can use a steel for the mutual axial stroke of the high-pressure piston contained therein wherein the steel insert has an annular chamber between the steel insert and the cylinder is defined by substantially the length of the piston stroke, and a fluid conduit means comprising the annular chamber the fluid in the high-pressure chamber connects to the hydraulic To balance pressure on both sides of the insert. The use can essentially over the length the high-pressure chamber extend.

The System may include: an atmospheric chamber at the remote End of the low-pressure chamber, in which the low-pressure piston and being moved, wherein the piston has an axial extending therefrom Stamp has a collection reservoir to from a piston / motor to obtain withdrawn fluid, one in an end wall of the low-pressure chamber formed cylindrical studs to sealed in the Record piston plunger and fluid from the collection reservoir to record it in the atmospheric Evade chamber, and a fluid outlet at the bottom of the atmospheric Chamber passing through a check valve with a low pressure accumulator or a low pressure chamber in conjunction stands, creating an insertion Piston stamp the atmospheric Chamber opposite the atmosphere concludes and compression of air in the atmospheric chamber opens the check valve to fluid from the bottom of the atmospheric Chamber to the low-pressure accumulator or the low-pressure chamber to pump.

The System may include: an atmospheric chamber at the remote End of the low-pressure chamber, in which the low-pressure piston and moved to a collection reservoir to be withdrawn from a piston / engine To receive fluid, an opening formed in an end wall of the low-pressure chamber, to obtain fluid from the collection reservoir and into the atmospheric chamber to escape, a stamping device formed in the piston for close this end wall opening, and a fluid outlet at the bottom of the atmospheric chamber, passing through a check valve communicating with a low pressure accumulator or chamber, whereby a reciprocating movement of the piston and punch device the atmospheric chamber across from the atmosphere closes and a compression of air in the atmospheric chamber opens the check valve to Fluid from the bottom of the atmospheric To pump chamber to the low pressure accumulator or the low pressure chamber.

The system may include: an atmospheric chamber at the distal end of the low pressure chamber in which a spring return plunger pump is mounted near the top of the low pressure piston and extends into the low pressure chamber to abut a barrier wall separating the low pressure chamber from the high pressure chamber at the top of the low pressure piston inlet formed by the low pressure chamber to the plunger pump, a normally closed check valve in the inlet for flow in one direction from the low pressure chamber into the plunger pump, and an outlet from the plunger pump to the atmospheric chamber, and a normally closed check valve in the outlet for flow in a direction from the plunger pump to the atmospheric chamber, whereby abutting the plunger pump against the barrier wall during reciprocal movement of the low pressure piston at the top of the low pressure chamber air into the atmospheric chamber. The Plunger pump may be mounted in the barrier wall, and a power device formed in the barrier wall will pump air directly into the atmosphere.

The System may include: an atmospheric chamber at the remote End of the low-pressure chamber, in which the cylindrical housing a Barrier wall having the high pressure chamber from the low pressure chamber separates, one in a valve seat formed in the barrier wall seated poppet valve, which is under tension, and usually a river of the high pressure chamber to the low pressure chamber to prevent, wherein the poppet valve projecting into the low pressure chamber shaft whereby hitting the low pressure piston against the Plate shaft opens the poppet valve, around a river of High pressure fluid from the high pressure chamber into the low pressure chamber to allow.

The System may include: an atmospheric chamber at the remote End of the low-pressure chamber, in which the cylindrical housing a Barrier wall, which the high pressure compensation chamber of the low pressure chamber separates, one attached to the high pressure piston and in the direction of the barrier wall projecting plate thumb valve, one in the barrier wall in fluid communication with the low pressure chamber formed valve seat for the plate thumb valve for receiving the plate thumb valve to the closure before a complete Discharge of the high pressure fluid from the high pressure chamber, and a in the barrier wall formed servo reservoir opening in fluid communication with the pump / motor device, whereby after closing the Tellerdaumenventils in the high pressure chamber residual high pressure fluid is directed to the motor pump.

The System may have a unified storage system in which the cylindrical housing with a valve block and with a center-type pump / motor device or not over center type Pump / motor device into a single structure for the direct Attachment is incorporated in a vehicle end drive.

Short description the drawings

The embodiments The invention will now be described with reference to the accompanying drawings described, of which:

1 is a schematic representation of a SHEP system known technique with an atmospheric fluid reservoir;

2 is a schematic representation of a fully sealed SHEP system of known art;

3 a schematic representation of the use of low-pressure tube reservoirs with cooling flow in the simple direction;

4 a schematic representation of the use of two low-pressure accumulators with cooling flow in the dual direction;

5 Fig. 12 is a schematic diagram of a SHEP system showing a longitudinal sectional view of a compensated memory;

6 is a fragmentary cross-sectional view of a compensated memory with multiple tie rods;

7 is a sectional view of the in 6 shown compensated memory taken along the line 7-7;

8th Fig. 12 is a longitudinal sectional view of a compensated position-sensing memory;

9 Fig. 12 is a longitudinal sectional view of a compensated accumulator with a valve block;

10 is a sectional view of the in 9 shown compensated memory, taken along the line 10-10;

11 is a fragmentary longitudinal sectional view of a compensated memory with internal connections;

12 is a sectional view of the in 11 shown compensated memory, taken along the line 12-12;

13 Fig. 12 is a schematic representation of a SHEP system with a longitudinal sectional view of an unbalanced compensated memory;

14 is a schematic representation of the in 9 SHEP system shown with a longitudinal sectional view of an external concentric low pressure accumulator and an unstressed high pressure insert;

15 is a longitudinal sectional view of an internal concentric low pressure accumulator and an unstressed high pressure insert;

16 Fig. 10 is a fragmentary longitudinal sectional view of a recharging compression pump for a sealed system;

17 is a fragmentary sectional view of the in 16 shown recharge compression pump in a closed position;

18 Figure 3 is a schematic representation of an atmospheric reservoir system with a fragmentary longitudinal sectional view of a recharge compression pump;

19 is a fragmentary longitudinal sectional view of a compression pump in a low-pressure piston;

20 is a longitudinal sectional view of an air cleaning system;

21 is a longitudinal sectional view of an end stop protection device;

22 is an enlarged sectional view of the spool valve 21 in a closed position;

23 is an enlarged cross-sectional view of the in 21 shown spool valve in an open position;

24 Fig. 10 is a fragmentary sectional view of an auxiliary high-pressure servo feeder;

25 is an enlarged sectional view of the in 24 shown servo feed in an open position;

26 is an enlarged sectional view of the in 24 shown servo feed in a closed position;

27 is a partially cutaway side view of a unitary construction with overcentre pump / motor means;

28 Fig. 10 is a partially cutaway side view of a unitary construction with non-overcentre pump / motor means;

29 Figure 3 is a partially cut away side view of a unitary construction with a non-flexible conduit over center pump / motor direction at a central position;

30 is a partially cutaway side view of a unitary construction with transmission gearbox; and

31 Figure 4 is a partially cutaway side view of a unitary reverse pump / motor assembly design.

description preferred embodiments

1 FIG. 12 shows a basic SHEP system consisting of, for example, a P / M unit connected to the drive train of a vehicle in a manner not shown, such that the P / M rotation is coupled to vehicle motion. Energy is stored in the high pressure (HP) 2 stored for long-term energy storage by a starter valve 3 can be sealed off. This reservoir typically has a precharge pressure of about 150 bar and a maximum pressure of about 350 bar, but could have other pressure ratios. A pressure transducer inputs the HP value to the control system, not shown. Since the P / M unit is typically a high speed axial piston unit, it requires a boost pressure, typically about 10 bar, as input when pumping to avoid cavitation at higher speeds. This is stored by a low pressure (LP) 5 provided. The transducer 6 enters the low pressure value into the control system. One in the HP store 2 Penetrating fluid becomes the gas in the chamber 2a compress and cause a pressure increase. At the same time, a fluid must leave the LP reservoir, forced by the LP gas pressure in the gas chamber 5a , so that the LP accumulator pressure must drop. The amount of waste depends on the relative sizes of the two stores. Normally, the LP memory will be larger than the HP memory, so that the LP memory pressure range is smaller than that on the high-pressure memory side.

If the vehicle brakes, the HP storage pressure will rise and the LP accumulator pressure fall off, and the reverse when the vehicle accelerates. The means that normally the LP memory pressure at low vehicle speeds and P / M rotation speeds is lowest, and at high speeds the highest. Within sensitive limits, this is a beneficial effect as the P / M a higher one Inlet pressure at higher Speeds needs to avoid cavitation, though operated as a pump.

The P / M unit licks some fluid into its housing, leading to the reservoir 7 is pulled away, which through the filter vent 8th open to the atmosphere. This is necessary for many standard P / M designs, as these are not designed to have any significant pressure, typically of the order of 1 bar, in their housing. This fluid is passed through the charge pump 9 returned to the system, and through the filter 10 and the radiator 11 returned to the LP memory page.

The charge pump can be operated in various ways. For example, a level switch in the reservoir may turn on the pump when the reservoir becomes full. In this case, the charge pump has a dual function of providing sufficient flow through the radiator to maintain the system at acceptable operating temperatures, as well as replenish the P / M housing leakage. If the required cooling flow is greater than the leakage, the pump must be started and its output through the pressure control valve 12 be circulated back. This valve is controlled to ensure that the correct amount of fluid is stored in the LP memory to balance the fluid currently stored in the HP memory.

The Charge pump must to each time their outlet pressure from atmospheric pressure to low pressure raise, which represents a considerable waste of energy, and reduces the overall efficiency of the storage system. At this Configuration is the P / M unit for over center operation (overcentre operation) so that they can act as a positive displacement pump operates and braking the vehicle and an overpass of Fluid caused by the LP to the HP memory. she works as a motor with negative displacement by taking fluid from the HP memory takes. The torque of the motor is a function of the offset value and the pressure difference, so that a Command of the driver from the control system translated into an offset value becomes.

Other systems use a P / M unit that is capable of only one side of the center operation, as in FIG US 4,760,697 which requires some additional control valves to switch from braking to accelerating.

It is advantageous, the gas volume of the HP memory with elastomeric To fill foam, because this makes its operation essentially isothermal, what with a significant improvement in effectiveness and fewer problems associated with high gas temperatures. The use of foam in the LP memory has little effect on efficacy, but carries to reduce temperatures.

The in 1 HP storage shown is defined as a bladder storage (bladder type), with foam containing the bubbles in the compartment 2a fills. This is in line with the accepted technique, but there are concerns about the long-term reliability of the bladder, as it not only has to deform itself, but also the foam as the store is being charged.

Ideally, the foam is not permeable and should compress with the gas so that there is little gas flow through the voids of the foam. Excessive flow could damage the foam and result in some loss of effectiveness. It is not possible to provide even compression with a collapsing bubble, possibly leading to deterioration of the foam and increasing bladder malfunction. 2 shows a similar SHEP system, but uses a P / M unit that can accommodate the LP in its housing up to about 10 bar. This is called a sealed SHEP system because it is isolated from atmospheric pressure.

The P / M unit 21 , the HP memory 22 , the starting valve 23 , the transducer 24 and the LP memory 25 act as with respect to the corresponding components in 1 described. In this case, the circulation pump 26 only by the pressure losses of the filter 27 and cooler 28 pumping, resulting in significant energy savings over the open SHEP system of 1 leads. A line 29 Provides circulating flow through the housing of the P / M unit, which is often a requirement for operations at high rotational speeds. However, the circulation pump is typically powered by the vehicle's electrical system, which is not an efficient path for the energy; from the generator to the battery, to the electric motor and finally to the pump. The pump could be operated at different speeds depending on the system temperature and minimum circulation requirements for power minimization, resulting in control complexity and higher costs. The pump is also another potential source of noise.

The LP memory 25 is shown as a conventional piston type accumulator. The sliding piston 30 must be long enough to be stable and not curl and not jammed in the hole. It is the usual practice to hollow out the piston on the gas side to minimize the total storage length since the gas will never be completely compressed. However, this design is not ideal for the foam because the foam / gas in the piston cavity will compress, requiring a flow of foam / gas from the main space into the recess, resulting in a twisting of the foam matrix and into a gas flow therethrough Gaps results. The HP memory is with the piston 31 shown facing the other side, so that the foam / gas space is compressed in a regular manner. However, there is an unusable volume of fluid in the piston requiring longer storage.

The change in LP storage pressure When charging and discharging the memory with HP fluid is the same as that for the system of 1 explained. In this case, however, the LP accumulator pressure also acts on the P / M housing and on its shaft seal, so that in practice the LP accumulator must be comparatively large in order to limit the maximum LP accumulator pressure within the ratings of the housing and the shaft seal , The P / M shaft seal is a critical component as it must remain leak-free over the range of low pressure accumulator pressures and P / M rotational speeds. In order to be accepted in the automotive industry environment, it must reliably maintain the sealed integrity of the system for the life of the vehicle.

3 shows an embodiment of the present invention that overrides the requirement for the circulation pump in a sealed SHEP system by using two LP memories; a first large store 45 and a second small store 46 , The P / M unit 41 , the HP memory 42 , the starting valve 43 and the pressure transducer 44 are like in the previous figures. When the vehicle is accelerating and the P / M unit is in the engine mode, fluid is flowing from the HP memory 42 through the P / M unit 41 to the first large LP memory 45 and through the check valve 49 to the second small store 46 ,

During braking, when the P / M unit is in the pumping mode, fluid flows from the LP stores 45 . 46 to the P / M unit to the HP memory 42 , The flow of the big LP memory 45 goes directly to the P / M unit, but the flow from the small store is through the check valve 50 through the P / M housing, the filter 47 and the radiator 48 before reaching the inlet of the P / M unit. This provides for circulation and cooling of a portion of the fluid during the half cycle. The check valves 49 and 50 can be reversed to provide for circulation during acceleration, if desired. The only loss of effectiveness is the pressure loss through the filter and the condenser, which can be selected in size to meet the actual cooling flow requirement, the size of the small accumulator being sufficient to provide this flow.

4 shows another embodiment that provides for circulation during the two modes of operation. During acceleration, when the P / M unit is in the engine mode, the main flow of the fluid is from the HP memory 42 to the LP memory 45 , the circulating river comes through the check valve 52 , the P / M housing, the filter 47 , the cooler 48 and the check valve 59 to the small LP memory 46 , During the braking operation, when the P / M unit is in the pumping mode, the main flow of the fluid is from the LP memory 45 to the HP memory 42 , The circulating river comes from the small LP memory 46 through the check valve 50 , the P / M housing, the filter 47 , the cooler 48 and the check valve 60 to the P / M input for transfer to the HP memory 42 , This effectively provides a circulation flow which is a small proportion of the fluid flow but a substantially fixed portion of the main flow. The compared with 3 More frequent flow through the radiator means that the radiator can be made smaller, with a smaller flow requirement, resulting in a smaller, smaller reservoir 46 leads.

One compensated or pressure compensated memory combined in more effective Way high and low pressure in a mounting arrangement, so that the flow in the HP side by the river of the LP side is balanced. In essence, it consists of two Piston accumulators, which are axially together with the piston via a Connecting rod are placed connected. US Patent No. 2,721,446 and US Patent No. 3,918,498, incorporated herein by reference, describe such a device. In its simplest form he dispenses with the requirement for LP memory, since the river in the HP memory through the river of the LP piston completely is compensated.

5 shows a SHEP system that has a compensated memory 62 used, the P / M unit 41 , the starting valve 43 and the pressure transducer 44 as before. The balanced memory 62 consists of a cylindrical housing construction, which is a preloaded gas / foam filled high pressure chamber 65 encloses with a reciprocating piston assembly which consists of an HP piston 66 , LP pistons 67 and an axial connecting rod 68 where all are provided with gaskets as shown. The chamber 69 to the left of the HP piston, as in 5 see, is connected to the SHEP HP fluid side, while the chamber 70 to the right of the LP piston is connected to the SHEP LP fluid side. The chamber 71 to the left of the LP piston is with the atmosphere through the filter vent 72 connected. The cylindrical shape of the HP foam / gas chamber is ideal in that the gas and foam can easily be compressed together without twisting the foam matrix or flowing gas through the foam gaps.

A flow of HP fluid into the storage HP chamber 69 will cause movement of the piston assembly to the right, an equal volume of fluid from the LP port 78 move and air through the ventilation opening 72 move in. Conversely, a flow of HP fluid from the feed cher 62 causing movement of the piston assembly to the left, and an equal volume of LP fluid in the LP chamber 70 pull, and air through the ventilation hole 72 also press. A small LP memory 75 is necessary to ensure that proper charge pressure is maintained at the P / M input and to compensate for volume changes due to system temperature changes and other factors. During a normal braking and acceleration cycle, there is no flow in and out of the reservoir, so that a circulation pump 76 is required. Unlike the in 2 In the equivalent system shown, there is no change in the LP when the memory is being charged and discharged, which means that the LP memory pressure at all times must be large enough for the P / M unit at its highest operating speed.

The piston surface 73 on the left side of the HP piston is due to the presence of the connecting rod 68 smaller than the area 74 on the right side. The connecting rod is due to the low pressure in the LP chamber 70 , which acts on the right side of the LP piston, held under low tension. The force balance of the piston assembly means that the HP fluid pressure will always be slightly higher than the HP gas pressure, by an amount that depends primarily on the relative size of the connecting rod. The smaller the diameter of the connecting rod, the smaller the difference between the fluid pressure and the gas pressure. A fluid pressure that is greater than the gas pressure is favorably within sensitive limits because the piston seal always acts in the same direction, regardless of the direction of the piston movement, it is better lubricated and it is easier, a fluid with relatively high viscosity than to seal a low viscosity gas.

The pistons 66 and 67 can compare with the pistons 30 and 31 ( 2 ) of short length, as they pass through the connection by means of the connecting rod 68 are stabilized, provided that the rod is both of sufficient diameter and suitably connected to provide stable support of the pistons. For practical purposes, this means that the connecting rod should be larger than would be required for easy against the low clamping force of the low pressure acting on the LP piston. The balanced memory causes a reduction in the overall size by about 25% of the volume, since the pistons are shorter than those in 2 shown and the significant LP gas volume is not required.

The 6 and 7 show a construction for a balanced memory in which the central connecting rod 68 out 5 of three equally spaced connecting rods 81 is replaced with a small diameter. This ensures stable support of the pistons 82 and 83 so that they can remain short in length while achieving a small overall tie rod cross-sectional area. The small cross-sectional area of the connecting rods reduces the difference in the effective area, so that the area 84 on the fluid side of the HP piston 82 only slightly smaller than the area 85 at the gas side, with the result that the fluid pressure is only slightly greater than the gas pressure in order to obtain a force balance. Typically, a pressure difference of about 10 bar with a maximum storage pressure of 350 bar can be achieved. This is considered ideal to provide for a stable sealing performance with a minimum of friction and wear.

It will be understood that more than three tie rods may be used, if required, to provide a design advantage. In a typical SHEP setup, the memory will be horizontal because this location is very easy to accommodate within the vehicle structure. Most memories for industrial energy storage purposes are mounted vertically. The in 7 shown construction has the further advantage that the rotational position of the piston is maintained, which allows the installation of position-sensitive devices in the piston, which would otherwise have to be installed in the storage enclosure.

Storage of the gas type are temperature-sensitive. The pressure of the elastomeric Foam effectively minimizes the effects of a temperature rise by compression, but the ambient temperature of a memory in an automobile can in large Dimensions vary, depending on the current one Weather conditions and other factors such as the proximity of the exhaust system and the heat transfer from the hydraulic fluid to the gas. Take, for example, an energy storage system, which has a designed pressure range of 175 to 350 bar is the P / M unit is sized, by the required train at full offset at 175 bar provide at higher To press a smaller offset is used. Pressures lower than 175 bar would be the can not provide designed traction, but can still do some useful Energy compared to motor driven vehicle propulsion systems provide. A conventional one Control using an HP storage pressure transducer would assume that the memory is empty when the pressure drops to 175 bar, so that this energy is not available.

If the HP gas to 175 bar at z. B. precharged 60 ° C, as designed working temperature, the precharge pressure will be about 135 bar at 0 ° C, which is a useful storage capacity of only 75% of Design results when only the range of 175 to 350 bar is used. In fact, if the full displacement of the accumulator from 135 bar to 350 bar is usable, more energy is available than when operated at the designed temperature, but with available traction falling to 75% when the accumulator is completely emptied.

Changing the lower cutoff of HP memory usage makes it difficult to use a pressure transducer for control. 8th shows a balanced memory, with built-in position sensors for control purposes in the atmospheric chamber and / or the LP fluid chamber. The use of proximity switches in a bubble type HP memory is impractical, and difficult in a piston type due to the high pressures.

The LP piston 91 moves to the left as in 8th to see if the stored energy is the vehicle until the sensor is triggered 92 accelerates, indicating that the memory is empty. During braking, the piston moves 91 to the right until either the sensor 93 is triggered, indicating that the memory is full, or the pressure transducer 94 signals that the maximum allowable pressure has been reached. This combination of position sensors and pressure transducers ensures the maximum usability of the memory over a range of temperature conditions. Under very cold conditions, an LP transducer that reads when the memory is empty can be used as a sensor 92 as used in US Pat. No. 4,367,786 by using engine coolant or exhaust gases. The position sensors 92 and 93 may be of any known type. Alternatively, a position transducer 95 long range, such as the supersonic type.

It is advantageous for a SHEP or hybrid hydraulic system to be packaged as a single sealed unit that can be installed in a fully assembled condition and tested hardware component in the vehicle; and not piece by piece, such as a normal hydraulic system in which connecting pipes are subsequently installed, the system is then filled with fluid, pressure charge, air bubbles, and test run. The 5 . 9 and 10 show a balanced memory 100 with wires 101 and 102 Holding the storage openings with a valve block 103 which contains all the valves required for the SHEP system.

The 9 and 10 show the wires 101 . 102 each in the corners 103 . 104 the arrangement so that the total package size is not increased. The 11 and 12 show a similar arrangement in which the lines within the compensated memory arranged by the piston 120 lead to a more compact and pleasing-looking package. High and low pressure pipes 111 and 112 are with the valve block 113 connected, the HP line 111 is with the HP side of the store by the way 114 connected. A seal 115 in the LP piston 120 who is the lead 111 orbited, prevents leakage when the piston passes through the connecting rod 118 is moved alternately.

The LP line 112 is with the LP side of the memory by the way 116 connected. A seal 119 in the LP piston 120 that the line 112 circled prevents leakage when the piston moves reciprocally. The diameter of the LP chamber 117 can be made larger than the diameter of the HP chamber, as shown, to provide a same piston area including the conduits.

13 shows a balanced memory 121 in which the HP piston 122 larger than the LP piston 123 is. This means that if the memory is charged during the braking of the vehicle, the influence to the HP side is not completely compensated by the outflow from the LP side, the difference being due to a small memory 124 is compensated. Similarly, if the memory is discharged during acceleration, the outflow from the HP side is greater than the influence to the LP side, the difference being to the small memory.

The four-way check valve group 125 with reference to above 4 described, operates so that the entire flow in and out of the small memory through the P / M housing, the filter and the radiator passes, and so the requirement for a circulation pump is avoided. The difference in piston diameters and the size of the small accumulator may be selected to provide any desired amount of circulation and a reasonable increase in the P / M input pressure when the main memory is depleted to accelerate the vehicle. The circulation process would also work well if the LP piston were larger than the HP piston, since only a difference in their sizes is required, but the change in the P / M inlet pressure would be negative as the main memory deflates, which would be a less favored option.

The system of 13 requires a small memory, which is unwieldy in terms of fitting into a unitary structure. 14 shows an annular small accumulator piston 131 that is integral and concentric with the LP end of the the same memory 132 is designed. The small storage piston 131 is an annular hoop that is reciprocal to the ring 135 is mounted and must have a sufficient length to be stable and not bend / bend in an annular cylinder. This arrangement can be achieved without significantly increasing the package dimensions as both the LP piston 133 smaller than the HP piston 134 is as well as the HP end must be built with a thicker wall than the wall thickness of the LP end to withstand the high pressure.

15 shows a further embodiment of the invention, the multiple connecting rods 141 of the 6 and 7 used, with the small memory 142 concentric within the LP piston 145 the balanced memory is attached. A small accumulator gas precharge, typically about 5 bar, passes through the charge valve 143 and by ways 144 introduced. The LP piston 145 is shown as an annular hoop and may be of short length since it is from the equally spaced tie rods 141 is held stable. The integration of the LP chamber integrated into the center of the LP memory eliminates the need for a separate LP memory to create a cooling flow. Flow from this central chamber is directed through the pump / motor housing for both the acceleration and braking modes.

The access opening 146 the small store is intentionally at the top of the storage cylinder 142 arranged to prevent air accumulation. The small memory is shown with the gas connection at the central plate of the compensated memory. It can be reversed with the gas connection on the end plate, if this is favorable for a particular construction. The small reservoir is shown concentric with the LP piston and cylinder, but can not be centered if convenient for a particular design.

US Patent No. 2,764,999 shows in 2 and US Patent No. 4,714,094 shows in 3 Storage structures in which the HP gas acts on the outside of the cylinder tube so that it is substantially stress-free, both patents are incorporated herein by reference. This construction, particularly that of the second disclosure, would be the preferred construction for SHEP applications, unless there was a need to use elastomeric foam in the HP gas cylinders.

15 illustrates a preferred design for the HP end of the balanced memory that is suitable for the use of foam. A stripped steel insert 147 provides the bore for reciprocal movement of the sealed HP piston 148 , In a conventional embodiment, this is part of the construction of the pressure vessel 151 and will expand under pressure and provide an increased extrusion gap for the gasket, and will be exposed to any dispersions that may occur during manufacture and / or subsequently due to attachment or other external forces. In this embodiment, unlike gas, as taught in the references, HP fluid is connected to the outside of the insert by connection galleries represented by reference number 149 are designated, so that the hydraulic pressure acts equally on the outside of the insert, and this can be essentially de-energized. Of course, this can also be applied to single piston storage. The illustrated construction shows the insert having the length of the HP piston stroke with a seal 150 which separates the fluid from the gas. Depending on the circumstances of the design, the insert may extend the full length of the HP chamber. The seal can be made by an adhesive tape between the insert and the pressure vessel 151 be replaced, especially if the pressure vessel consists of a composite structure. The provision of some circulation of the fluid between the cartridge and the pressure vessel may be used to warm the HP gas with the hydraulic fluid to improve both the storage capacity of the reservoir and to provide some cooling to the hydraulic system.

hydraulic systems are for external leakage of hydraulic fluid prone, and great care must be taken when designing and installation of the system to provide a reliable solution. A SHEP system must work for the entire Lifespan of the vehicle must be free from external leakage. One of the for the minimization of possibilities Leakage loss strategies used is all external minimize dynamic seals and ensure that those who are inevitable, dense only at low pressure, preferably at atmospheric Print. atmospheric Seals can the same level of reliability such as engine and gear box shaft seals conventionally for road vehicles be used.

In the context of a SHEP sealed balanced reservoir system as described herein, there are two external dynamic seals, namely the P / M shaft seal and the LP piston seal. Both of these seals are exposed to the low pressure of about 10 bar. The shaft seal is the most critical because it is a significant task to produce a rotating seal that provides drip-free performance for years at such pressure rotating as well as stationary over a range of operating temperatures. It is a much simpler task to provide a seal that has certain drop losses.

In this situation, it is common practice to have a second seal with a returning suction to an atmospheric reservoir. A sealed SHEP system (such as in 2 however, does not have an atmospheric reservoir or a charge pump to pump back drop of seal drip to the hydraulic system. The 16 and 17 represent a means of overcoming this disadvantage by the atmospheric chamber 161 a balanced reservoir is used as an atmospheric reservoir, and by the mutual action of the LP piston 162 as a charge pump works. An atmospheric suction 163 is provided to the P / M unit by using a second shaft seal in a manner not well-known, but well-known to rotary seal manufacturers, that communicates with a pump reservoir 164 is connected, preferably integral with the filter vent opening 165 , The pump reservoir sucks into the gallery 166 , Any leakage from the pressure wave seal of the P / M unit, along with any leakage from the LP piston, will then be at the bottom of the atmospheric chamber 161 collected.

The check valve 167 makes a connection from the atmospheric chamber to the LP side 168 ready, connected to the small store 169 , The check valve 167 is normally kept closed by the LP pressure. Preferably, the check valve should be of a soft-seated design to be free of leakage itself. The LP piston moves to the left when the contents of the memory are discharged. A pestle 170 is formed at the end of the LP piston, which in a sealing manner with the gallery 166 coupled. 16 shows the piston position just before the gallery is completed. Once the gallery is completed, the remaining volume is in chamber 161 completed and another thrust of the piston to the left, as in 16 seeing it will compress the air with any fluid in it.

17 shows the balanced reservoir completely discharged, with the HP piston 171 at the left end of his hub. The final volume 172 at the atmospheric chamber is designed to provide a compression ratio of about 4: 1 after it is initially completed and removed from the plunger 170 has been isolated. If there is no fluid from the leakage, the gas in the remaining volume is compressed to produce a pressure of about 6 bar, not enough to the check valve 167 open against the low pressure, so that no gas is forced into the hydraulic system. When there is fluid from the leakage, the volume of air is reduced, but the change in volume remains substantially the same, so that the compression pressure is increased until it reaches a value equal to or greater than the low pressure, at which time some of the fluid is forced back into the hydraulic system on the floor of the atmospheric chamber. This provided in automatic charging system. The pump reservoir works to store any leakage that may occur during the time the main memory is completely discharged and there is no access to the atmospheric chamber.

The same system can also work on an open reservoir SHEP system (such as in 1 shown) to recirculate the housing drop flow from a P / M unit to an atmospheric pressure housing as described with reference to FIG 18 is shown. The P / M case drip losses 181 arrive at the atmospheric reservoir 182 , Abundance 183 arrives at the atmospheric chamber 184 to enter the LP memory 186 through the check valve 185 to be pumped back. The memory 186 works in combination with the opening 187 both to maintain LP pressure and to smooth the pulsatile delivery for each charge and discharge cycle from the compression pumping system. This system has the advantage of automatically pumping the casing drop flow only when it occurs.

18 shows the balanced reservoir with equal piston diameters, but unequal piston diameters can be used if the housing drop flow does not provide sufficient circulation.

19 shows a further embodiment of a compression pump, which uses a balanced memory with multiple connecting rods so that the pistons are held in a defined verticality, which is the charge-return valve 191 allowed in the flask 192 to be attached. A spring loaded ram 193 closes instead of STEM 170 ( 17 ) the entrance opening 194 to provide the same compression pumping action as previously described with respect to the embodiment of FIG 17 explained.

One of the functions of the reservoir in a system utilizing an atmospheric reservoir is to allow the escape of any air introduced into the system during initial assembly and filling, or during subsequent service. It is inevitable that some air pockets will remain in the hydraulic system after it has been filled. If these bags during the initial run of the system is pressurized, this air is gradually dissolved in the fluid. For example, normal hydraulic oil contains about 10% by volume of dissolved air at atmospheric pressure. This amount increases proportionally with the pressure so that saturation at two atmospheres would result in 20 vol% when returned to atmosphere. Since the oil entering the system is saturated at atmospheric pressure, the additional air released under pressure will increase the amount of air above 10%. Then, as the oil circulates back to the reservoir, the air is released to the atmosphere. This process provides for continuous air cleaning of the hydraulic system, and is an important but little known factor that supports the effectiveness of the hydraulic system.

Sealed SHEP systems have no atmospheric reservoir, so the trapped air has no chance of escape. Current practice is to circulate the fluid through an atmospheric reservoir during testing, by means of a separate circulation pump, and long enough to allow all trapped air to be removed. This process is unreliable and time consuming, especially for industrial storages that lie on their side, capturing a large amount of air. Piston type accumulators offer an advantage in that the apertures are easily positionable to minimize the amount of trapped air, as with reference to FIG 15 explained.

Assuming the presence of a charge pump, such as of the type previously described, automatic air cleaning of a SHEP system can be achieved as now with reference to FIG 20 is described. With a compensated accumulator with multiple connecting rods, so that the verticality of the piston is fixed, the connection 201 to the LP chamber 202 positioned in the direction of the bottom of the reservoir so that any free air will tend to be trapped at the top of the LP chamber. As far as possible, the rest of the system, including in particular the P / M housing and the small memory, will be designed and connected to minimize air entrapment. The connection to the small store 203 is shown by way of example at the top.

A small spring return tappet pump 204 is in the LP piston 205 attached so that they are in contact with the barrier wall 206 is operated when the system is fully charged, with a piston movement completely to the right. The inlet to the plunger pump pulls away from the top of the LP chamber 207 to pick up any air that may be present and then through the hammer-in check valve 208 , The delivery of the pump passes through the outlet check valve 209 to the atmospheric chamber 210 , The spring strength of the check valve 209 must be strong enough to hold back the LP pressure so that there is only one flow when the plunger is operated.

alternative could the ram pump be mounted in the barrier wall and by contact with the LP piston be operated, and then by means of lines with the atmospheric Chamber be connected. This would be required if the verticality of the pistons not secured would. Any Pumped air will escape through the filter vent. Under normal conditions, it will only be the hydraulic fluid that is pumped. When the dissolved Air greater than the 10% saturation (for oil) at atmospheric Pressure is exceeded, the excess air is discharged and through the filter vent opening Outside reach. The charge pump will then return the fluid to the Pump the system. Continuous operation of the system, the fluid through the atmospheric Chamber revolves, will tend to be resolved Air in the system slowly towards the atmospheric saturation level bring to.

So long no mechanical stopper for the HP piston is provided, there is a risk of the connecting rod (s) to span, if the store is ongoing is charged after the LP piston reaches the end of its stroke Has. While the use of a position sensor system, as described above, a Tax system would allow To prevent this occurrence, there is an advantage in being an automatic To have a system that is positive for preventing such an occurrence acts.

The 21 . 22 and 23 show a preferred embodiment of such an end protection system. 21 shows a balanced memory 211 , with a HP piston 212 that's the HP gas 213 from the HP fluid 214 separates. The LP piston 215 separates the LP fluid 216 from the atmospheric chamber 217 , The two pistons are connected by a number of connecting rods 218 connected by the central plate 219 with seals 220 go through. The storage is through the HP opening 221 charged, with LP reflux from the LP port 222 is provided. These flows are reversed during unloading of the store. The central plate has an end stop (EOS) valve 223 built-in.

Regarding 22 : The EOS valve consists of a darning poppet valve 224 that with a valve seat formed in the central plate 225 is coupled. The poppet valve is loose in the valve guide 226 carried. The valve guide has a number of holes 227 to allow fluid flow and is in the central plate by a retaining ring 228 held. The poppet valve is from the spring 229 pushed into the closed position, between the valve guide and the poppet valve through the washer 230 and the retaining ring 231 acts.

These embodiment uses a self-aligning poppet valve design with a frusto-conical Seat and a matching spherical Area on the poppet valve. additionally to be closed by the spring, the valve will go through the effect of high pressure kept closed. The piston assembly moves to the right when the memory is loaded until the LP piston reaches the end of the poppet valve plug. Further movement works to the opening of the valve and to relieve the high pressure in the low pressure, which causes the fluid to recirculate to the pump inlet.

23 puts this effect with the LP piston 232 which opens the valve to a flow path 233 to allow. This system simplifies the control of the energy storage system, since it is then allowed to fully charge the storage without worrying about damage and reduces the need for accurate position detection or accurate pressure compensation with compensation due to temperature. Provided that suitable cooling is provided, a system with this built-in valve can provide continuous vehicle braking with the P / M unit after the accumulator is fully charged, as the kinetic energy of the vehicle is converted to the fluid through the throttling action of the EOS To warm the valve.

It is usual Practice to use a portion of the stored HP fluid as a servo stock Control of the P / M unit to use, since this eliminates the need lets, one to provide another source of servo energy. However, this leads to trouble if the memory is completely discharged, because then no HP servo fluid available is. This can be overcome by using a voltage of the P / M control be, by a suitable spring or other means, so that the P / M Unit inherent to the blow but it is difficult to provide a fast control response.

Out For this reason, it is usually the practice of a complete discharge of the memory during Normal use, so that servo printing is always available, the spring tension only for the initial one Startup is used when the memory inevitably completely discharged is. This prevents the full energy capacity of the memory used and leads to a complex control, which requires an accurate measurement of the position the piston assembly and / or an accurate measurement of pressure and temperature requires.

The 24 . 25 and 26 illustrate a preferred embodiment of a means for automatically preventing the complete emptying of the memory so that a residual amount of HP fluid remains available as a servo stock. The 24 shows a balanced reservoir, as previously described with HP and LP pistons connected by a plurality of connecting rods which extend through the central plate. There are two HP openings, one main opening 241 and a servo storage opening 242 , The valve arrangement 243 is preferably a thumb valve, which can be better understood with reference to the 25 and 26 as a valve plate 244 with a hat 245 shown connected by a threaded device to sliding on a drop 246 attached, which is fastened by means of a threaded device on the HP piston. A feather 247 pushes the plate assembly so far away from the HP piston, as far as the head 248 allowed on the stopper.

A valve seat 249 is installed in the central plate. This seat couples with a corresponding mating surface on the plate when the thumb valve is closed. This embodiment uses a self-aligning thumb valve design with a frusto-conical seat and a mating spherical area of the thumb valve. The piston assembly moves to the left, as in the 25 and 26 to see when the store is unloaded. As the HP piston nears the center plate, the thumb valve closes against the seat in the central plate and includes a quantity of HP fluid that can not be further discharged through the main HP port. However, the servo opening is still open and HP fluid is available through this opening.

26 shows the construction of the thumb valve when it closes and after some servo flow has been used. The HP piston 250 contacts the central plate 251 just not yet, with the plate seals against the seat. The plate assembly has moved the plug partially down against the spring. The plate assembly is also kept closed by the action of the high pressure, since the main opening is no longer under pressure.

Further consumption of servo fluid would cause the HP piston to be moved closer to the center plate until it contacts. Then no further servo fluid would be available. The stroke of the plate assembly on the plug easily surpasses the closing stroke of the HP piston, so that the main contact between the HP piston and the central plate takes place and not through the thumb valve assembly. The thumb valve simplifies the control of the energy storage system, since it is then allowed out of the To completely discharge main HP opening and still retain some energy for servo operations, which reduces the need for accurate positioning and / or accurate pressure measurement with compensation for the temperature. The thumb valve provides an additional benefit in that the pressure on each side of the seal of the HP piston is considered substantially equal during normal operation, with the seal only required to hold the full gas precharge pressure when the servo is completely discharged ,

One SHEP energy storage system consists of a number of components, which are mechanically and interconnected by fluid lines, which then charged with gas under pressure and with hydraulic fluid. The Loading is critical for the successful operation of the system, taking the right gas pressure and the right amount of fluid is required. After the initial Loading the fluid is contaminated with air, which is purified from the system must become. From the point of view of vehicle assembly, it is desirable that the energy storage system a complete one uniform arrangement is that fully loaded, cleaned and has been tested before installation, in exactly the same way as a conventional one Vehicle transmissions. The energy storage system then only requires a connection to the external control devices, whether electric or mechanically, to a fully functioning To be unity.

27 shows a compact memory arrangement 251 as they relate to 15 has been described, which is a valve block 252 has built in as he relates to 10 has been described. An over center type of a P / M unit 253 is mounted directly on the assembly, with all connections within the assembly itself. The assembly is mounted in a vehicle with resilient attachments to minimize noise and vibration transmission within the assembly. The drive shaft 254 may be connected to the drive train with a universal propeller shaft, whether on the transmission or on the axle, depending on the design of the vehicle. The unit assembly can be mounted directly on the transmission and be part of the overall machine and transmission arrangement. If the vehicle has a chassis-mounted driveline with universal shafts to the wheels, the unitary assembly may be mounted directly on the driveline.

The 28 shows a similar arrangement with a memory array 261 and a valve block 262 as described above, and with a non-hypercentric P / M unit 263 as part of the arrangement. The wave 264 may be connected to the drive train as previously described. A cooling system 265 and filters 266 are also shown as part of the unit array. The 28 shows the pressure compensated reservoir directly attached to the valve block, with filter and radiator attached directly to the valve block. It also shows the pump / motor unit attached directly to the valve block. This arrangement can, as in 29 shown reconfigured with the pump / motor unit directly on the valve block at the center of the unified storage system. This allows the complete system to be filled with oil, bled or air and pre-tested prior to installation in the vehicle.

The 29 shows such a further embodiment, wherein the valve block 271 between the HP end 272 the memory array and the LP end 273 attached, and the P / M unit 274 attached to the valve block as before.

30 shows the addition of the transfer box, which allows the system to be included in the drive train. This structure is generally suitable for commercial vehicles such as buses, in which the cardan shaft connecting the engine and the transmission to the axle passes through a transfer housing 281 can be interrupted. In this embodiment, the unit assembly includes the transfer case. The transfer housing can transmit the drive through gearboxes, transmission chains or drive belts. Each of the waves 282 or 283 may be connected to the transmission, the other shaft is then connected to the axis.

The 31 shows a change in the structure of 30 , which is more suitable for vehicles with limited width between the chassis rails. The P / M unit 291 is mounted on the front, in the direction of the vehicle engine, and substantially in line with the storage arrangement. The P / M unit 291 is on a transfer case 292 attached with its shaft not shown pointing backwards. The LP end 293 the balanced memory is mounted on the rear side of the transfer case, then the center plate 294 and the HP end 295 , cables 296 connect the central plate to the P / M unit. Any required control valves may be mounted either in the central plate or in the opening block of the pump or distributed on them. The transmission wave 297 is connected to the vehicle engine with a conventional drive shaft. Since the P / M unit is located to the front, there is enough length for a universal connector shaft. The other wave 298 is connected to the rear drive axle of the vehicle by using another conventional drive shaft. The 31 represents the execution An over-centered P / M unit. A non-over center design, such as the one in 30 , can also be used. Although the unitary structure has been described in connection with a particular compact memory design, the same principles can be applied to other memory arrangements.

Claims (26)

Hydraulic energy storage system for use in a vehicle, comprising a high-pressure accumulator ( 42 ), a first low-pressure accumulator ( 45 ) and in parallel a second low-pressure accumulator ( 46 ) and a pump / motor device ( 41 ), which is in fluid communication with the high pressure accumulator and with the first and second low pressure accumulator to pump fluid from the first and second low pressure accumulator to the high pressure accumulator when the pump / motor is operated in a pumping mode and to supply fluid to the first and second accumulators second low pressure accumulator when the pump / motor means is in a motor mode, the pump / motor means having a housing to circulate through this fluid, characterized in that the system further in series between the pump / motor means and the second low pressure accumulator first Check valve ( 49 . 59 ) in order, when the pump / motor means is in the motor mode, to flow a fluid portion in a direction from the pump / motor means to the second low pressure accumulator, in series between the housing of the pump / motor means, the second low pressure accumulator and the pumps / Engine setup a radiator ( 48 ) in flow communication, and in series between the second low-pressure accumulator and the pump / motor housing housing a second check valve ( 50 ) to flow fluid in a direction from the second low pressure accumulator through the pump / motor housing housing and the radiator to the pump / motor means when the pump / motor means is in the pumping mode to cool that portion of the fluid. Hydraulic energy storage system according to claim 1, further in series between the pump / motor means, the pump housing and the radiator, a third check valve ( 52 ) to allow fluid to flow in a direction from the pump / motor means through the pump housing and the radiator when the pump / motor means is in the engine mode, the first check valve (14) 59 is in series with the radiator to flow a portion of fluid in a direction from the radiator to the second low pressure accumulator to cool that fluid portion, the system further in series with the radiator a fourth check valve (10). 60 ) to, when the pump / motor means is in the pumping mode, allow fluid to flow in a direction from the second low pressure accumulator to the pump / motor housing and through the radiator to the pump / motor to cool that portion of fluid. Hydraulic energy storage system according to claim 1 or 2, comprising a compensated accumulator containing the high-pressure accumulator and the first low-pressure accumulator ( 62 ), the compensated accumulator comprising a cylindrical housing having a longitudinal axis and a high pressure chamber ( 65 ) and a low pressure chamber ( 71 ), which are located concentrically with the longitudinal axis, a transversely mounted in the high-pressure chamber high pressure piston ( 66 ) for a mutual axial stroke in the high-pressure chamber and a transversely mounted in the low-pressure chamber low-pressure piston ( 67 ) for mutual axial stroke in the low-pressure chamber and at least one connecting rod ( 68 . 61 ) to connect the high-pressure piston and the low-pressure piston with each other. A hydraulic energy storage system according to claim 3, wherein the compensated accumulator comprises at least three equidistant rods (Fig. 81 ) connecting the high pressure piston to the low pressure piston to hold the pistons perpendicular to the longitudinal axis of the cylindrical housing during the reciprocal stroke. A hydraulic energy storage system according to claim 3 or 4, wherein the low-pressure chamber has a gas end remote from the high-pressure chamber and a fluid end located near the high-pressure chamber, a first position sensor ( 92 . 95 ) is mounted in the low pressure chamber near the low pressure end, and a second position sensor ( 93 ) is mounted in the low pressure chamber near the high pressure end, wherein the first and second position sensors monitor the reciprocal lift of the low pressure piston in the low pressure chamber. Hydraulic energy storage system according to claim 5, additionally comprising a pressure sensor ( 94 ) in fluid communication with the high pressure chamber, the second position sensor or the pressure sensor monitoring the reciprocal lift of the high pressure and low pressure pistons and actuating a heating system. Hydraulic energy storage system according to claim 5 or 6, wherein the gas end has an end wall and wherein the first position sensor ( 95 ) is mounted in the end wall. Hydraulic energy storage system according to claim 7, wherein the first position sensor in the End wall is mounted at the height of the longitudinal axis and has a supersonic transducer. Hydraulic energy storage system according to one of claims 3 to 8, in which the compensated accumulator comprises a valve block ( 103 ) at one end of the cylinder housing, a high-pressure fluid line connecting the high-pressure fluid end to the valve block ( 101 ) and a low-pressure fluid end connected to the valve block low-pressure line ( 102 ) having. Hydraulic energy storage system according to claim 9, where the high pressure and low pressure lines outside of the cylindrical housing run. Hydraulic energy storage system according to claim 9, in which the high pressure and low pressure lines within the cylindrical housing are arranged parallel to the longitudinal axis and through the Low pressure piston run, with an additional in the low-pressure piston provided sealing device is provided to slidably on high-pressure and low pressure lines to couple and seal them. Hydraulic energy storage system according to one of claims 3 to 11, in which one of the high pressure chamber and the low pressure chamber a larger diameter as the other has, one of the high pressure and low pressure pistons a larger diameter as the other has to be a river imbalance between the High pressure cylinder and the low pressure cylinder to cause the pumps / motor device in fluid communication with the high pressure chamber and with the low pressure chamber is to transfer a fluid from the low pressure chamber to the high pressure chamber to pump when the pump / motor device operated in a pumping mode and to return fluid to the low pressure chamber when the pump / motor means is operated in a motor mode, a low-pressure accumulator in parallel is arranged with the low-pressure chamber to during the pumping mode or the Motor mode due to flux imbalance between the high pressure cylinder and the low pressure cylinder one To obtain fluid content of the high pressure or low pressure chamber and deliver. Hydraulic energy storage system according to claim 12, wherein the high pressure piston is larger than the low pressure piston is, whereby the outflow of the high pressure chamber is greater than the influence in the Low pressure chamber is to maintain a high fluid pressure and a positive flow imbalance from the high pressure cylinder to the low pressure cylinder. Hydraulic energy storage system according to claim 13, in which the low pressure accumulator is an annular chamber concentric is formed within the low-pressure chamber, and an annular accumulator piston having, for mutual hub in the annular Storage chamber is attached. Hydraulic energy storage system according to claim 14, in which the annular Accumulator piston an elongated annular Ripe. Hydraulic energy storage system according to claim 4, comprising a low-pressure chamber storage cylinder, the central in the low pressure chamber concentric with and within the low pressure ring piston is formed, one between the low pressure storage cylinder and the sealing piston formed by the annular piston, whereby the annular piston in sliding coupling with the low-pressure accumulator piston, wherein the Pump / motor means in fluid communication with the high pressure chamber and with the low pressure chamber and the low pressure accumulator is to a fluid from the low pressure chamber and from the low pressure accumulator to pump to the high pressure chamber when the pump / motor device in a pumping mode, and fluid from the high pressure chamber the low pressure chamber and return to the low pressure reservoir, when the pump / motor device is in a motor mode, wherein the cooler is in fluid communication with the low pressure accumulator, whereby the to the low pressure accumulator and away from flowing fluid through the radiator flows, when the pump / motor is in the pump or motor mode. Hydraulic energy storage system according to claim 16, in which the low pressure storage cylinder one in its upper Area formed access opening to vent air into the atmosphere. Hydraulic energy storage system according to claim 16 or 17, wherein the high-pressure chamber is a steel insert ( 147 ) for the reciprocal axial stroke of the high pressure piston contained therein, the steel insert defining an annular chamber between the steel insert and the cylinder of substantially the length of the piston stroke, and having fluid conduit means connecting the annular chamber to the fluid in the high pressure chamber to balance hydraulic pressure on both sides of the insert. Hydraulic energy storage system according to claim 18 wherein the insert extends substantially the length of the high pressure chamber. Hydraulic energy storage system according to one of claims 3 to 6, 9, 10, 12 to 15, comprising an atmospheric chamber ( 161 ) at the distal end of the low-pressure chamber in which the low-pressure piston reciprocates, the piston having an axial punch extending therefrom; 164 In order to obtain fluid extracted from a piston / motor, a cylindrical lug formed in an end wall of the low pressure chamber to sealingly receive the piston ram and to receive fluid from the collection reservoir to withdraw it into the atmospheric chamber, and a fluid outlet at Bottom of the atmospheric chamber through a check valve ( 167 ) is in communication with a low pressure accumulator or low pressure chamber, whereby insertion of the piston stamper seals the atmospheric chamber from the atmosphere and compression of air in the atmospheric chamber opens the check valve to draw fluid from the bottom of the atmospheric chamber to the low pressure accumulator or the low pressure chamber pump. Hydraulic energy storage system according to one of claims 3 to 6, 9, 10, 12 to 15, comprising an atmospheric chamber ( 161 ) at the remote end of the low-pressure chamber, in which the low-pressure piston moves back and forth, a collecting reservoir ( 164 ) to receive fluid drawn from a piston / motor, an opening formed in an end wall of the low pressure chamber to receive fluid from the collection reservoir and withdraw into the atmospheric chamber, a plunger means formed in the piston for closing this end wall opening, and a fluid outlet at the bottom of the atmospheric chamber through a check valve ( 167 ) is in communication with a low pressure accumulator or chamber, whereby reciprocation of the piston and stamper closes the atmospheric chamber from the atmosphere and compression of air in the atmospheric chamber opens the check valve to draw fluid from the bottom of the atmospheric chamber to pump the low pressure accumulator or the low pressure chamber. A hydraulic energy storage system according to any one of claims 3 to 6, 9, 10, 12 to 15, comprising an atmospheric chamber at the distal end of the low pressure chamber in which a spring return plunger pump ( 204 ) is mounted near the top of the low pressure piston and extends into the low pressure chamber to abut a barrier wall separating the low pressure chamber from the high pressure chamber, an inlet formed at the top of the low pressure piston from the low pressure chamber to the plunger pump, a normally closed check valve (US Pat. 208 ) in the inlet for a flow in a direction from the low-pressure chamber into the plunger pump, and an outlet from the plunger pump to the atmospheric chamber, and a normally closed non-return valve ( 209 ) in the outlet for flow in a direction from the plunger pump to the atmospheric chamber, whereby pumping the plunger pump against the barrier wall during reciprocal movement of the low pressure piston pumps the air present at the top of the low pressure chamber into the atmospheric chamber. Hydraulic energy storage system according to claim 22, in which the plunger pump is mounted in the barrier wall, and a conduit means formed in the barrier wall, air directly into the atmosphere inflated. A hydraulic energy storage system according to any one of claims 3 to 6, 9, 10, 12 to 15, comprising an atmospheric chamber at the distal end of the low pressure chamber in which the cylindrical housing has a barrier wall separating the high pressure chamber from the low pressure chamber, one in one the barrier wall formed valve seat seated poppet valve ( 224 ), which is under tension, and normally to inhibit flow from the high pressure chamber to the low pressure chamber, the poppet valve having a shaft projecting into the low pressure chamber, thereby causing the low pressure piston to strike the poppet shaft to open the poppet valve to prevent flow of high pressure fluid from the valve Allow high pressure chamber in the low pressure chamber. A hydraulic energy storage system according to any one of claims 3 to 6, 9, 10, 12 to 15, comprising an atmospheric chamber at the distal end of the low pressure chamber in which the cylindrical housing has a barrier wall separating the high pressure equalization chamber from the low pressure chamber, one at the high pressure piston mounted and in the direction of the barrier wall protruding Tellerdaumenventil ( 243 ), a valve seat for the poppet valve formed in the barrier wall in fluid communication with the low pressure chamber for receiving the poppet valve to close it prior to complete discharge of the high pressure fluid from the high pressure chamber, and a servo reservoir opening formed in the barrier wall in fluid communication with the pump / motor means after closing the plate thumb valve in the high pressure chamber residual high pressure fluid is directed to the motor pump. A hydraulic energy storage system according to any one of claims 3 to 25, comprising a combined storage system, wherein the cylindrical housing is provided with a valve block and with an excess pump / motor device or non-center-type pump / motor device is incorporated into a single structure for direct attachment to a vehicle driveline.