MECHANISM Of DRIVE FOR VEHICLES USING a HYDRAULIC PUMP AND an ENGINE

The present invention relates to drive mechanisms suitable for driving the drive wheels of vehicles, and it relates, more particularly, a mechanism original drive for driving a vehicle, employing an engine driven at a substantially constant speed at which the efficiency is optimized.

The crisis In front of 1' energy to which the world faces, it is imperative to produce vehicles having the largest possible yield, consuming as little fuel as possible and emitting as little secondary combustion products as possible. The conventional internal combustion engine used to drive mechanisms for vehicles is, significantly, low cost effective, particularly since it is operated over a range of extended speed, wherein the yield varies greatly. The present invention uses a prime mover driven at a substantially constant speed, so that it can optimize the energy efficiency and minimize emissions. Means are provided for altering the operating speed of the prime mover according to the range of desired speeds of the vehicle.

For example, operable the prime mover TO a first relatively low speed for automobile in cities, for example at speeds below about 50 to 65 km/h. The prime mover may operate at a different speed, higher, to run the vehicle in the campaign, for example at rates greater than 65 km/h. For any given operating, maintaining the speed of the prime mover constant for optimizing fuel efficiency and minimize emissions.

The prime mover drives a hydraulic pump which drives, in turn, a hydraulic motor. The output rate of the pump is adjusted to determine the velocity and direction of the vehicle. A fluidic circuit bypass is used to allow rolling freewheel the vehicle forward in the direction of movement, it seems preferable in particular that the vehicle is prevented from rolling freely in the opposite direction. Therefore, can be used the driving means of the vehicle as a braking device of secoure , so that, if the vehicle brake system fails, may be the drive mechanism in question "inverted" mode to prevent coasting and produce a natural braking of the vehicle.

Although is used to drive sources.

constant speed previously, and that is used also combinations comprising an engine and a hydraulic pump, it does not appear to that is used previously mechanism (installation) car driving apparatus, using a machine constant speed motive driving a hydraulic pump that drives, itself, a hydraulic motor, to provide the movement of a vehicle on the entire allowable speed range, e.g. zero to 130 km/h and more.

Patent publication The and below are representative of the prior art.

United States Patent

of America Marketing Authorisation No. Date patent

2 431,719

3 352,373

3 509,721

3 587,765

3 612,202

3 637,036

3 817,341

3 892,283

The publication; Manual Engineering Application , Bulletin 9565,

Rev. E., January 1975. Edited by Sundstrand Hydrotransmission , Ames, Iowa, that is part of the group of Sundstrand Corporation.

The single figure of the attached drawing represents in synoptic form of a functional chart block a preferred example non-limiting of the invention.

The figure is a drive mechanism for driving a vehicle such as an automobile. The mechanism is incorporated in the vehicle, and it uses a prime mover 10, such as an internal combustion engine, e. g., a gasoline engine or a diesel engine. The prime mover 10 is-indicated as variable speed, and it is controlled by a speed regulating mechanism conventional 12. For any particular operating, the prime mover is operated 10 • at a substantially constant speed. This rate may vary according to the operation of the rêhicule. Therefore, for the city traffic, little:

example, is will adjust the speed of the prime mover to be relatively low, while, for circulating rural, the speed of the prime mover will be substantially constant and relatively high. ÎO The prime mover 14 drives a hydraulic pump which is, preferably, displacement type variable rate comprising a swash plate 14a to determine the flow rate of output fluid of the pump. The swash plate 14a can be driven by a swash plate control 16 to determine the flow rate and direction of the fluid exiting the pump. The pump 14 is coupled to a hydraulic motor 18 via lines fluidigues 20 and 22. 24a and 24b The arrows indicate the direction of flow of the fluid between the pump and the motor in the conduits 20 and 22 for the forward run of the vehicle. Bypass A fluidic circuit 26 is inserted between the fluid lines 20 and 22 ; it comprises a on-off valve 28 and a shut-off valve (or retaining) 30. •The shut-off valve only passes the fluid in the bypass circuit that in the direction of arrow 32, i.e. in the direction of a) the fluid line 22 that returns fluid the motor to the pump when the vehicle is in forward motion to b). the fluid line 20. The bypass circuit is conçù for the coasting of the vehicle, the reverse gear of the vehicle, as well as the braking of the vehicle in the event of failure of the brake system, and will result in greater detail hereinafter.

A drain line 34 connects the motor 18 and the pump 14. A additional drain line 36 from the pump 14 to a cooler 38 which cools the hydraulic fluid present in the hydraulic system. The cooler transmits the fluid to a filter 40 to dirt. The.

fluid from the filter passes to a tank 40 and 42, thereof, at load terminal 44 of the hydraulic pump 14.

The hydraulic motor 18 drives a drive shaft or primary conventional 46 via a device 48 of overdrive, if desired. The device overdrive is controlled by a control 50 conventional overdrive.

The system according to the invention operates in the following manner. Assumed as an automobile using The a drive mechanism of the type shown in Figure is to roll, for example, city traffic at a rate of less than, for example, 50 km/h. Is adjusted the speed of the prime mover by suitably setting the speed command 12, so that a maximum rate of the fluid from the hydraulic pump 14 produces an engine speed corresponding hydraulic 18 emanating from the engine for the vehicle is traveling at 50 km/h. The prime mover is adjusted so that its speed remains substantially constant and does not vary, that the vehicle is at rest or is operating at any speed in the range of O to 50 kg/hr, for example. With the vehicle at rest, the swash plate 14a of the hydraulic pump is in the neutral position. It does not pass fluid through the ducts 20 and 22 and, accordingly, the secondary shaft or output 18a of the hydraulic motor is stationary. When *" that is desired to move the vehicle in a forward direction, the swash plate 14a is switched from the neutral position to a position corresponding to the forward. This change in state of the swash plate is controlled by the swash plate control 16 which can, for example, form a conventional accelerator pedal in an automobile. The fact that the swash plate 14a leaves its neutral position causes a fluid circulation, indicated by the arrows 24a and 24b, in the fluid lines 20 and 22. The fluid passes through the hydraulic motor 18, driving its output shaft 18a and causes corresponding movement of the drive shaft 46 of the conventional polyester mâme. The vehicle speed forward is established exclusively by the position of the swash plate 14a of the hydraulic pump, determined by the swash plate control 16.

The bypass circuit 26 acts by allowing the vehicle from driving in free wheel as follows * The valve all-rou-nothing 28 is in the passing position, to allow fluid to flow in the circuit 26 in the direction of arrow 32. Both that the hydraulic pump 14 drives the hydraulic motor 18, it does. not flow of fluid in the bypass circuit; on the contrary, the flow of fluid takes place from the hydraulic motor 18 in the hydraulic pump 14, via line.

fluid 22. Each time that the swash plate 14a is "released" to reduce the speed of the vehicle, however, the pump 14 functions to reduce the flow rate therethrough. In the neutral position of the swash plate 14a, it cannot go fluid by the hydraulic pump. The hydraulic motor on the other hand continuous, because it is coupled to the drive shaft (transmission) of the vehicle, to rotate and act as a pump. The fluid from the engine flows 18, because it will not be received entirely in the pump 14, in the branch circuit and 26 it would bypass the pump 14 without passing through it. Therefore, the bypass circuit 26 receives the difference of fluid flow rates between the hydraulic motor 18 and the hydraulic pump 14. This action allows coasting of the vehicle. Without such a bypass circuit, the vehicle would be automatically braked by the action of the hydraulic pump 14 which decreases the rate of fluid passing through it.

The usage characteristic of the drive device for braking is possible by a.

short circuit of the type shown in Figure. In particular, if drawing the on-off valve 28 in the "locked" position, while the forward direction, the bypass circuit is substantially removed from service. Therefore, all of the fluid passing by the hydraulic motor 18 is to pass through the hydraulic pump 14. In the case where the swash plate 14a passes in the neutral position, for example, by producing a desired state of non-passage of fluid through the hydraulic pump, there is automatic vehicle braking Such a mode of operation is useful, in the case where the vehicle brake system fails.

When it is desired to reverse the direction of travel of the vehicle, is passed the swash plate 14a controlled by the swash plate control 16 from the neutral position to a reverse position from the forward position. In this case, the direction

of passage of the fluid in the lines 20 and 22 is opposite to that which is represented by arrows 24a and 24b. To obtain the reverse gear of the vehicle, is passed on-off valve 28 in the "locked" position. Otherwise, the hydraulic motor 18 would be completely bypassed through the bypass circuit 26, the.

that would allow fluid to flow from the hydraulic pump 14-through the bypass circuit in the direction of the arrow 32.

Therefore, the valve 28 prevents fluid passage in the bypass circuit, allowing the hydraulic motor 18 be driven in the opposite direction in. It should be noted that, because there is no bypass circuit to function for the reverse gear of the vehicle, the vehicle is capable of rolling freewheel, which is possible when it is in forward motion. Could allow the vehicle from driving in reverse free wheel by incorporating a fluid circuit similar to the additional bypass circuit 26, with a cut-off valve operated to pass fluid in a direction opposite to that indicated by arrow 32. The two shunt circuits should not, of course, be in operation simultaneously. Could achieve this by an appropriate coupling between the valves on-off of the two circuits, so that, when a valve is open, the other closes automatically; the two could be open at the "neutral" state.

Could effect braking at any time by reversing the state of the on-off valve, when the vehicle is in motion.

Therefore, controlling the motion of the vehicle by means of the swash plate control and 16 of the forward/reverse 28a both. As has been found the the swash plate control 16 can form the conventional accelerator pedal in an automobile. Since the swash plate 14a conventionally is biased by spring in the neutral position, can be suitably used an accelerator pedal controlled by the toe and the heel for passing the swash plate in position forward and reverse.

The control front/rear 28a can be coupled to the controller

swash plate 16 if desired, or there may be a separate control lever, as desired. The rate adjustment mechanism 12 is conventional, and it is used to select the speed of the prime mover 10 compatible with the desired speed of the vehicle. When it is desired to increase the maximum speed of the vehicle speed band is adjusted properly the speed command 12 of the prime mover. However, during vehicle operation, the speed of the prime mover remains substantially constant, as aforesaid.

It has installed an installation of the type represented

in Figure in a vehicle mark "Ford Mustang" of 1966. The motive source 10 is made by a gasoline engine "Wisconsin" four-cylinder, " VH 4D model^M . The camshaft has been modified to give a maximum torque to about 1800 rpm, instead of about 2200 turns/tan, typical value in the engine. Carburization are also modified by replacing the carburetor vertical inverted by a carburettor, to reduce toxic emissions. Furthermore, is used the injection of air to both the intake pipes and reducing exhaust emissions.

The hydraulic pump 14 is made by a displacement pump variable rate "Sundstrand", "model 21-2023", manufactured by Sundstrand Corporation. The hydraulic motor 18 was also a motor "Sundstrand, model 21", in this case a displacement motor fixed rate. Using a device The overdrive " Hone model 3,000, № 4372, Hone -O-drive gear", manufactured at Santa Fe Strings, California. The on-off valve 28 was a valve assembly ball "Petro". The shut-off valve 30 was a high-pressure shut-off valve "Teledyne Republie ".

With the internal combustion engine "Wisconsin" particular used, the rotational speed of the motor can vary between about 1400 and 2800 revolutions/tan. This provides a corresponding output rotational speed of the hydraulic motor 18 for the said assemblies identical. An output drive shaft 1800 rpm corresponds to a vehicle speed of about 117.5 km/h. Therefore, an output of 2800 turns/nn of the drive shaft corresponds to a vehicle speed of about 183 km/h. The. device 48 overdrive increases, of course, the output speed of the drive shaft than that 1' can be obtained without the device. The motor "Wisconsin" described above is very cost effective in the range from -1400 to 2000 rpm, which corresponds to a maximum speed of about 132 km/h (without overdrive). For the line

^..

urban/the internal combustion engine is to fonctioftn & t * 2r*envj.wn 1400 rpm. For the pipe in rural, the motor will operate up to about 2000 rpm to have the best performance. The motor speed is changed only when the range of speeds of the vehicle changes, > for example when passing from the urban driving to the pipe in rural or vice versa.

Although preferred in this case that the hydraulic motor 18 or a displacement motor fixed rate, it is possible to use a displacement hydraulic motor variable rate. With such an engine displacement hydraulic variable rate, different ratios, between the input drive of the hydraulic pump and the output shaft of the hydraulic motor are possible. It should be the control of the swash plate in a variable displacement hydraulic motor and, in the installation represented ^ in the drawing of the present application, the use of a displacement hydraulic motor fixed rate greatly simplifies the commands to be used.

It is possible to use a conventional automotive engine, for example-higher power that the motor "Wisconsin" above. Typically, the camshaft of such an engine will be rectified specially passing the rotational speed range corresponding to a maximum output at about 1400 to 1800 rpm. The rate of compression is to be normally reduced to cause less emission of pollutants. The modifiéepour carburetion is to be be "free-flowing", i.e. include a vertical carburetor without acceleration pump mechanism, andc. The ignition timing should be further adjusted to reduce the pollutants. With such modifications, a conventional automobile to high power motor consuming, for example, may consume Xm 15.77 1/100, with the passage at a installation hydraulic drive Xm about 5.26 1/100. With the motor "Wisconsin" and installing hydraulic drive described above, it appears that can be obtained in a 2.25 1/100 to 2.37 Xm vehicle Xilogrammes 1360. The foregoing structure, using a conventional exhaust assembly, can, is believed to arise, reduce the pollutant emissions to about 0, 4% carbon monoxide, with 25 parts per million of hydrocarbons.

It should be noted that the present invention provides excellent yields of use of the fuel and substantially reduced pollutant emissions.

Clearly, modifications can be. made to the embodiments just described, in particular by substitution of equivalent technical means, without separating the purpose of the present invention.