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130mpg Hydraulic Car
:: 23 August, 2007
The piston of the free-piston internal combustion engine pumps hydraulic fluid into the accumulator. It stores the energy by compressing the gas bladder inside. The engine will be turned off automatically when the accumulator is filled – and turned on again shortly before it becomes empty.
The pressurized fluid drives the wheelmotors, one in each wheel. Their driving power is continuously variable from zero to maximum speed.
The wheelmotors are reversed during braking and become pumps. They are powerful enough to stop the car like disk brakes, while recuperating the entire braking energy. The energy is stored in the accumulator and used again for driving. The ‘round-trip-efficiency’ during braking is 70% to 85%. The energy is stored in the accumulator and will be used again to drive the car.
News Inside News:
About Valentin Technologies-
Valentin Technologies develops a new hydrostatic powertrain for vehicles. The technical experiences are based on more than 15 years of product development with leading manufacturers in this field.
Proof of Concept Models of the hydraulic motor have been tested successfully in 1986/87. Test for maximum power and durability in Bulle, Switzerland, and efficiencies at very low powers (< 0.5%) in Madison, WI, USA.
Grants for the development of a prototype of the hydraulic motor have been obtained by the Department of Energy, Washington D.C., and the State of Wisconsin in 1989 with a total of $240.000 - less than half of the requested.
The Hydraulic Motor, Free-Piston Combustion Engine, and the Fuel Injection System have been patented in Germany and The United States. International Patents have been applied for. US Patents: 6,406,271 B1 – 6,293,231 B1 – 6,484,674 B2.
Currently, we are preparing our participation for the Automotive X-Prize to validate the concept. The X-Prize Foundation awards here a $ 10 Million prize for a production capable four seat passenger car. The races of the competition are planned for 2009. Valentin Technologies is approaching well known, highly future oriented individuals and corporations for financial support for the development of the car.
The Ansari X-Prize for the ‘First Privately Developed Reusable Spacecraft’ has generated $ 120 million of earned media according to the X-Prize Foundation.
Concept of this car-
The 130 MPG Car is a medium size 5 seat passenger car. The driving comfort is improved and driving distance and space requirements fulfill currently established standards. However, driving performance, fuel consumption and emissions are significantly better.
The drastically increased mileage results from the new Hydrostatic Powertrain with Energy Storage. The powertrain is significantly smaller and lighter. Its main components are joined together to a drivable car platform. The structure is very rigid and includes energy absorbing active bumpers. Because of this structural arrangement, the car body is not exposed to high loads and crash forces, and is therefore lighter in weight and less costly.
The functioning of the Hydrostatic Powertrain with Energy Storage and the high power of its wheelmotors make it possible to recuperate the entire braking energy. A new type of combustion engine converts the fuel energy more effectively into mechanical power and reduces the emissions. Its small size and low heat radiation allows for a car body with low air drag.
Summarizing: The drastically increased mileage and reduced emissions are the result of the above factors: Reduced weight, lower air drag, a more efficient powertrain and the recuperation of the entire braking energy
Hydrostatic Powertrain
The 130 MPG Car is driven by a new Hydrostatic Powertrain with Energy Storage. This type of powertrain concept is currently used to drive construction and other equipment where their ability of continuously variable speed is indispensable.
Hydrostatic powertrains use pressurized fluid to transmit the energy. Controlling the flow of power is here very easy and the storage of energy fast and efficient. The power density of the components is high when compared with other drive systems. However, the hydraulic motors as main components of hydrostatic powertrains do not fulfill the very extensive requirements regarding speed range, efficiency, weight and cost as required for an automotive drive system.
The components of the new hydrostatic powertrain are specifically designed to overcome these shortcomings. As the result, the new powertrain fulfills the needs of an automobile better than the current systems.
The three main components of the new powertrain, building the platform of the car, are:
1. Wheelmotor driving the car.
2. Accumulator providing the wheelmotor with power.
3. Engine charging the accumulator with pressurized fluid.
1. The wheel drives the car:
The wheelmotor consists of a hydraulic axial-piston motor and a single planetary gear stage. The concept of using a hydrostatic drive, located directly in the wheel hub, is made possible by drastically improved technical data of the hydraulic motor. The main improvements are:
a. Speed range
b. Torque range
c. Weight
d. Efficiency – Losses
+ 100 %
+ 75 %
- 65 %
- 30 %
There is one hydraulic motor in each wheel, driven by pressurized fluid from the accumulator. They provide high power to accelerate and drive the car. The power at each wheel can be adjusted very fast and continuously by the powertrain computer to improve the driving and braking performance.
The motors are powerful enough to stop the car within the shortest possible distance. During braking, the motors are reversed to pumps, charging the entire braking energy back into the accumulator. Due to higher loads at the wheel during braking, the motors in the front are larger and have 230 hp each. The car has a total of 670 hp.
The wheelmotors are noticeably smaller and lighter than the disk brakes they replace.
2. The wheelmotor is driven by energy from the accumulator:
The accumulator is a container for pressurized fluid, the energy which drives the car. The bladder at the inside is charged with pressurized gas (Nitrogen) and fills the whole container when the accumulator is empty. When fluid is pumped into the accumulator to store energy, the size of the bladder shrinks and the pressure increases.
The maximum amount of stored energy is 1.8 MJ at 6,800 psi., an equivalent of 0.68 hp over a period of one hour. Or e.g. 600 hp for ca. four seconds when storing the recuperated energy during hard braking. Because of the high pressure, the accumulator has thick container walls and possesses therefore a very high flexural stiffness. It is fabricated from carbon fiber to reduce the weight.
The accumulator assembly is the load bearing backbone of the car platform. To fulfill the additional requirements, the wall thickness is increased slightly and suspension points are built in for attaching the engine and wheel suspension.
The container technology is comparable to that of currently used tanks for PNG (Pressurized Natural Gas). During an excessive impact, the non-flammable Nitrogen will be automatically released.
3. The engine charges the Accumulator with pressurized fluid:
The 2-stroke Diesel engine with two opposed free-pistons, transfers the combustion pressure directly into pressurized hydraulic fluid. This engine concept provides best air-exchange conditions, is very robust and basically free of vibrations. Crankshaft and valve mechanisms are not needed, reducing the frictional losses, and the size and the cost of the engine. In addition, a high bore to stroke ratio is applied to obtain a very desirable compact combustion chamber.
The drawback of free-piston engines has been an insufficient control of the piston movement. A new hydraulic control mechanism and the electronic powertrain computer determine now the piston movement and therefore the compression ratio, speed and dead center positions. These conditions allow for an optimized combustion process for a large variety of combustible fuels, reducing emissions and consumption.
The engine charges the accumulator only for a short period of time, and will be turned on and off automatically by the powertrain computer. When operating, the engine runs only at constant speed and power. The new fuel injection system with peripheral micro-slot injection improves the preparation of the air-fuel mixture noticeably. These conditions allow for a highly optimized combustion process, minimizing fuel consumption and emissions.
The pulse-pressure charger transfers the exhaust pressure wave directly into the intake air pressure wave. Further improved combustion conditions and a higher power density are the expected outcome. EGR (Exhaust gas recirculation), a common measure to reduce the emissions further, can more easily be integrated.
Fuel consumption-
The only energies needed to drive a car are used to:
1. Move the car body through the air.
2. Roll the tires over the street.
This requires typically only about 1/5 of the consumed energy. The remaining 80% are lost or used for accessories.
1. Moving - Reducing these losses is reached by:
a. Low air drag.
The shape of the car body determines the air drag. A practical comparable size for the passenger compartment has been considered here. The air drag of current cars is high, because of unfavorable air flow underneath the car and the needs to cool an inefficient engine. Best air drags of production cars are 0.27 - and of experimental cars below 0.16. An air drag of 0.22 is used in the calculation of fuel consumption.
b. Low weight.
Lower weight requires less power to accelerate, move, and brake the car. However, if the power for accelerating the car is mainly recuperated braking energy, the weight of the car is here of lesser importance due to a smaller and lighter powertrain.
The small and light powertrain and the self-supporting structure of the car platform, reduce the overall weight of the car considerably. Cars of comparable size currently weigh ca. 3,100 lb. Due to a lighter, smaller powertrain and simpler car body - a weight of 2,200 lb has been used in the calculation
c. Low rolling resistance.
The resistance is determined by the quality of the tire (rolling resistance) and the weight of the car. Best current coefficients of rolling resistance are 0.0055 to 0.007. A coefficient of 0.0060 has been used in the calculation.
2. Rolling
To increase the overall fuel consumption, the losses within the powertrain and those from braking have to be significantly lowered. Both losses are considerably reduced by separating the operating profile of the engine from that of the car. This is made possible by the accumulator, acting as buffer between both operational requirements. The functioning is here obtained by:
d. Constant operating conditions for the engine.
Independent from the power needs of the wheelmotors, the engine charges the accumulator under full power and only for a short period of time. Here, the engine operates under its best possible operating conditions of constant pressure and speed to minimize fuel consumption and emissions.
In addition, the free-piston engine has inherently fewer losses and is significantly lighter, reducing the weight of the car. Best current engines have a specific fuel consumption of 0.310 lb/hp·h but operate at an average of 0.450 lb/hp·h. A consumption of 0.284 lb/hp·h (175 gr/kW·h) has been used in the calculation.
e. Recuperation of the entire braking energy.
Braking consumes a large part of the energy, about 40% during city driving of the NEDC. This is twice as much as energy used for driving at constant speed. The recuperation of this energy with a high ‘round-trip-efficiency’ reduces the consumption considerably.
The high power peaks during braking require very powerful drive motors to recuperate the large amounts of energy. Motors which are large enough to accelerate the light car (e.g. 200 hp) are too small to recuperate the entire braking energy (600 hp).
The calculation of fuel consumption is based on the 130 MPG CAR driving the NEDC Cycle. (New European Driving Cycle). This, as other standardized driving cycles, does not reflect a typical driving pattern. The effectiveness of the Hydrostatic Powertrain improves under more realistic conditions.
The fuel consumption for constant speeds is:
110 mpg @ 60 mph
170 mpg @ 30 mph
Benefit -
The new Car offers the same roominess as a typical 5 seat passenger car, but noticeable improvements are achieved in the important areas of:
1. Fuel consumption
130 mpg - instead of 27 mpg. - and more than a comparable reduction in emissions.
2. Safety
Active bumper absorb the entire crash energy from a 25 mph impact. The forces the passenger is exposed to are significantly reduced and damage to the car body are basically eliminated.
Individual control of power of each wheel improves the road holding characteristic.
3. Driving comfort
The active suspension absorbs most of the road bumps and basically eliminates banking. The lower center of gravity improves the handling.
4. Performance
The high power of the wheelmotors provide outstanding acceleration. 0-60 mph in 5 sec.
5. Cost
The operating costs are significantly reduced. In long terms, the production costs of the new car will not exceed those of conventional cars.
Contact:
VALENTIN TECHNOLOGIES, INC.
14900 Westover Road
Elm Grove, WI 53122 (USA)
Phone: 262-821-1901
Fax: 262-821-1910
Email: Valentrain@msn.com
In The Images-
1.130 MPG Car
2.The graph shows the main technical data of the car
3.principle of the Hydrostatic Powertrain with Energy Storage.
4.The wheel is driving the car
5.The wheel is driven by the energy from the accumulator
6.The Hydrostatic Powertrain of the 130 MPG Car
7.The engine charges the accumulator with pressurized fluid
Release link: http://www.valentintechnologies.com
