Automotive Technology

This matter was already discussed link . Maybe anyone have information about HLA tests in real life ?

I have done some studies on Hydraulic Drive including a drag race car which could potentionly run the 1/4 mile, without the engine turned on, at speeds over 160 mph. Quite impressive. A diesel engine is well suited to hydraulic drive because of it's high torque values at low speeds. The sweet spot is closer to the operationg range of conventional hydraulic pumps. Also and electric/hydraulic hyd-bred is optmized because the electric drive would run at "average" load allowing the hydraulics to do the "peak" loading. This makes a smaller electric drive possible saving a lot of "peak" oversizing in the electric system. MIKE L.

Hello, some notes about "turbine-electric generator-el.wheel motor" conception

1. "Hydraulics are heavy, messy" - if you will compare hydraulic transmission power density (5-6 kW/kg) and electric transmission power density (2-3 kW/kg) you will change your mind. Ofcource, leakages is great disagvantage, but not "heavy"

2. Efficiency of gas/kerosine turbine in a range below 80 kW lesser than deisel or petrol engine. Only in Abrahams tanks and railway trains I know installs turbines.

3. Energy storage during brake cycle is limited by maximum charging current for accumulator. And this is reason why toyota prius accumulators can not be applyed on heavy trucks. You may suggest capacitor does have such limitation instead of accumulator, but size and weight of such CAPACITOR will be really huge. Hydraulic accumulator can absorb energy very fast and more compact than accumulator.

4. Please, do not have so much dreams about solar panels on vechicle. It can be used only on very light "cars", on very strong sunshine, without strong winds. So you can use such "cars" only like "golf cars" in desert.

I think we always throw the baby out with the wash water.. Hydraulics is one way to capture kinetic energy rapidly where electric can't compete.. why can't the electrical and mechanical people get together and think tank both together? I can see hydaulic capture and then transfer that to electric. As far as power to weight and size hydralics can't be beat. Hydraulic accumulators have not even been tapped. Imagine even using the hydraulics to capture enough energy to run a air conditioning unit in the car instead of electric or gas power.. Use the wasted braking power for something or even use it to get back up to speed after stopping. Then run on electric or gas.. The savings would be significant! If someone wants to get together on this just let contact me.

As far as being messy I have seen a lot of hydrostatic systems run for years without leaks.. design is the key.

There is in fact a micro turbine powered electric bus manufacturing company in the US that has sold buses to Disney and NY City transit. I've had it here in my county fleet operation for evaluation...pretty impressive to operate and very fuel efficient, includes regen braking. DesignLine International. I believe company originates from New Zealand.

Actually, Chrysler pretty much solved the turbine exhaust temperature problem by using a ceramic heat transfer wheel to use the exhaust to preheat the incoming air. The result was much more efficient turbine that exhibited mileage equal to conventional engines (Chrysler was considering selling the resulting turbine car in 1977, but ran into money problems). The real problem with turbines remains the slow throttle response. However, as a generator, as you suggest, the speed would be kept constant, so no problem. There might be enough residual exhaust heat to run air conditioning and heating systems, but that would require a thorough design study.

After working around hydraulically driven heavy equipment, I've thought about building a hydraulic custom hotrod. I like that there is no drivetrain business to deal with. Hydraulic lines could be run cleanly through the frame rails leaving the undercarriage completely smooth. The engine could be placed where ever I want it.

With hydraulic motors at each of the 4 wheels that could be modulated to very specific speeds independently, think about the traction control potential!

I can't see hydraulics performing very well as they are only 60% efficient there is alot of power lost as heat where electricity is alot more efficient .

The power losses are not as high as gasoline engines.less than 40% yet we still use them.. and the ratings I've seen for hydraulics have been upwards of 85% efficient.. the important thing to remember is regenerative. That's 100% inefficient.. if you don't capture it.

Hydraulics can approach easy 80% eff. the thing about hydraulic motors is the high torque availible at almost 0 rpm. Hydraulic motors are allowed to stall at near full torque with no damage to system. Stall an electric motor and see some smoke! This is why electric drives are oversized to accomadate the starting torque. With variable volume pumps and variable volume motors all connected to a storge accumulator the actual "drive unit" wether electric, gas engine, diesell engine or ? is now sized for average output not peak load. Regenerration thru recharge of the accumulator during braking is possible.During idle or periods of small loads the "drive could actully be shut down when the accumulators are at full (not max) pressure.If you get alot of heat in any hydraulic system this is an indication of inefficiency and can be avoided thru proper design. MIKE l>

Hi engineers !

You have shared opinions because you don't know the THP-Engine (thermo-hydro-pneumatic) that already exists.The patented invention (RO-116494 B) owned by a Romanian inventor since 1992 is the technology for hyd-bread cars.How it works ?Any engine :gas, diesel, wankel or turbine which can drive a hydro-pump is usable.Some pressured monoatomic gas accumulators with heat exchangers inside, thermic insulated,at least 2,are used.During the compression in one accumulator, the gas is simultaneous cooled by heat exchanger and the cool side of an (e.g.) absorption heat pump, achieving an isothermic compression.The recovered compression heat is added by the heat pump with its own heat and moved to the next accumulator where the gas is already (isothermic) compressed in the prior cycle, heating the gas by other heat exchanger and the hot side of the heat pump .Furthermore the gas is overheated by other heat exchanger by the exhaust gases and ready to expand producing useful work.The heat pump is driven by the heat of cooling installation .The procedure called by the author (Ion G. Nemes) "Regenerative Isotherme) is the way to enhance the efficiency not just for car powertrains but also for the energy industry e.g. for storage peak power plants (CAES) and wind energy storage .The accumulators working no more as passive storage devices (like gravity or springs) but much more as thermic engines inside the thermodynamic cycle , a process called by the author as "Active Energy Storage".The process was patented in 2004 again under RO-120353 and was awarded by Gold Medal by the 2006 Bruxelles International Salon for Inventions and New Technologies.The technologies were also offered on the official site of EU for technologies transfer from 2006 till 2008.They were also offered to the main carmakers,and now reoffered to EATON which in cooperation with EPA already produces 10 delivery trucks for UPS based on the oldest technology :just recovering the brake energy in passive , old way. We hope nevertheless that somebody from EPA or from DOE will take the offer seriously and will fund the RD&D at least for the school buses fleet as we already proposed them. Anybody interested ?

nemes.invent@gmail.com

Our present system of internal combustion powered transport has been arrived at through a process of evolution. This meets the needs of the consumer - cheap, ease of use, and convenience.

Until an alternative comes along that can meet all these criteria or surpass sufficiently 1 criteria to offset deficiencies in the others, the general public will not embrace any new system.

Most hybrids at present still use an internal combustion engine as the original source of energy but with improved efficiency. The main difference is the ratio of primary to secondary power. Do you have a large internal combustion engine and use the smaller hybrid as a supplement from regenerative energy or do you have a smaller fully loaded engine providing input to your larger hybrid drive system. The trade off in all systems is cost to buy, increased mass, lower performance and/or range.

The main advantage of electic over hydraulic would be the inclusion of plugin capability which would allow the vehicle to be used to a limited extent without the need to carry any fuel. In this case the ratio of fuel/electric would govern which of the criteria are better served ie. cost, performance

It would not be difficult to "plug in" a small electric/pump combination to "charge up" an accumulator so the hydraulic vehicle could also be run "without the need to carry any fuel".

As to preformance how about 750 ft-lbs of torque at zero rpm in a motor that weighs about 150 lbs?

OK, if the charge pump was not monted on the vehicle then you have to return to the pump to charge and public would need to learn how to connect/disconnect the hydraulic lines. If it is mounted on the vehicle, extra mass and space, but familiar electrical connection.

BTW - how much hydraulic fluid would you need to carry (mass and space) and what pressure would you need (storage vessel structural mass) to give resonable performance and/or range

As you indicated it would be easier to have a charge pump located on the unit. If charge time is "overnight", similar to charging a full on battery vehicle, the charge pump could quite small. More likely the "main drive" would charge the accumulator prior to starting off.

Volume of fluid depends on size and preformance required. A reasonable reserve of 5-10 gallons (16-37 liters). the pressureized storge device today is quite combersome a 5 gallon unit weighs in about 80-100lbs empty. A sleeved carbon fibre device could help but are not commercially availible yet. MIKE L.

This discussion it is better to lead in two ways:

1. Prime movers (energy sources): diesel, mini tubine, hydrogen cells.

2. Transmission of power from energy source to wheels:

- mechanical shafts and gear box: good efficiency, but poor power accumulation during brake cycle, good power/weight ratio. Compatible with internal combustion prime movers.

- elecrical transmission: good efficiency, average power accumulation, poor power/weight ratio. Compatible with deisel and mini turbine (generator needed) and hydrogen cells (no generator needed).

- hydraulic transmission: average efficiency, good power accumulation, good power/weight ratio. Compatible with deisel and mini turbine.

3. Cost is for hydrogen cells and mini turbine might be 3-4 times more than cost of diesel. When you will get back this money on energy economy? Cost of electrical accumulators in electrical transmission also 2-3 times highter than hydraulic accumulator. So, when you will get back your investitions in electrical roadster if efficiency of el. transmission 80% and hydraulic is 60%?

Maybe we are now looking at a tri-brid

Primary system - electric motor and battery storage - plug-in and regenerative charging used for short trips and acceleration

secondary system - internal combustion engine to provide constant baseload power to primary system for longer distances and touring.

tertiary system - hydaulic transmission with small accumulator to accept input from primary and secondary systems and distribute energy to drive wheels or charge batteries.

No not a tri-bred too much weight with battery storage and redundant hydraulic storage. More so either an electric drive with hydrgen/fuel cell (not peaked to produce acceleration but averaged to maintain cruising capability) or a smaller diesel or gas power plant again sized to maintain cruising (30-60 HP) and running at its most efficient single speed driving a variable pump which remotely (via hose) drives a hydraulic motor and keeps a hydraulic accumulator charged for passing and accelaration.

As for microturbine prime mover - you can see that efficiency 65/230=0.28 - is so close to diesel engine! What is profit? May be in coming years efficiency will be increased. Maybe DesignLine International Holdings have extra knowledge in this matter. Even they prooved to New York City Transit that their turbine based hybrid is better than diesel based hybrid.

I certainly appreciate the amount of thinking that has gone into this commentary. Yes, the only reason we have the current systems (diesel otto cycle internal combustion) is because they were what was feasible at the time they were thought up (over 100 years ago!) Recall that Otto Diesel started out using lamp oil/vegetable oil whatever hydrocarbon fuel he could find- no petroleum diesel available yet!! My tenent with the micro-turbine is it's ability to run on just about anything you dump into the tank (ANY hydrocarbon-based fuel, even used engine oil (filtered)) by virture of it's computerized mixture control, and in any combination (obviously not petrol because it's too volatile). The turbine runs at a constant speed (at it's highest efficiency) soley for the prupose of generating electricity. The vehicle would only be practical if it had some kind of storage means for this electric power- whether it is some kind of battery, capacitors, or a combination (batteries for travel, capacitors for accelerating). The electric motors built into the actual "rims" (the vehicle would also feature a hubless-style rim to save more weight) and the elimination of the entire drivetrain less an electric cable to transmit the power would all drastically save weight to devote to the battery system. Obviously this vehicle would be a dramatic leap forward in technology and require a substantial investment in R&D for it to be practical/affordable but what price do we put on the future of the earth's ecology?? If we must insist on high-speed travel from place to place we must be willing to step away from nineteenth century technology and take that 'giant leap for mankind' (sorry, couldn't help it). I look forward to more discussion, and haven't completely ruled out hydraulics except for: the weight, the mess (you can't stop it from leaking!) and the possible hazzards from high-pressure fluid. Thanks!!

Once you add some form off electrical storage then you should add in a plug-in recharge capability. Mains electricity will always be cheaper/greener and more efficiently generated than on-board generation.

In hub motors, either hydraulic or electric require some form of flexibility in the supply connection to allow for suspension travel and steering if using all wheel drive. If you want to get resonable performance comparable to our present vehicles ie. 80kW for a small hatchback - AWD 20kW per wheel or 40kW for 2 wheel drive. Even if you acheive a 25% reduction in vehicle weight you could reduce that to 15kW and 30kW, but that still requires a reasonable size cable/hose connection.

Great leaps forward tend to have a very slow uptake from the public. A gradual evolution will often acheive the final goal quicker (hare and the tortoise).

As an electrician if you equate pressure to voltage and current to flow, then the same idea of higher pressure for lower flow creates the same problems as higher voltage for lower current.

There are some thought provoking ideas listed in the thread. One I did not see was the problem of most turbine units; that of the need to maintain an extremely clean intake air supply. Detroit Diesel experimented with a turbine engine for bus use in the 1980s with their Toroflow engines and because of the harsh environment that it operated in, they had to abandon the idea because of the constant compromising of the air filtering system. I understand the worse evironment that tanks operate in, but they pay extemely close attention to the filtering system. I do not beleive that the typical car owner would pay that close attention to the filtering system.

Next, the addition of 10 to 30 gallons of hydraulic fluid for every vehicle will have environmentalists skeptical verses the electric motor solution. The high pressures and heat within the system create hazards during accidents that have not been fully addressed. So, while these technologies appear to have great promise, the practical aspects will have to be addressed before any radical changes in engine or propulsion systems are accepted by the car consumer or manufacturer.

One other comment I would like make is the idea that running a turbine engine at the "sweet spot" is more efficient that an engine that varies the horsepower and torque according to the needs of the wheels. Anytime that a car does not optimize the output torque and horsepower for propulsion, it runs less efficient. Trains have run for decades with large diesel engines that produce electricity, but do not power the wheels. This loss of kinetic energy, not used by the generator, reduces the overall thermal efficiency of the system. Similarly,turbine engines would reduce this overall thermal efficiency in the same way that train engines lose it...by not powering the wheels. Trains use an electric only propulsion system to maximize torque because of the huge tonnage that has to be moved at start up. Since electric motors produce almost 100% of its torque at strart up, this works well for trains. Although, recently, hybrid trains have been built that correct this inefficiency. The first one being unvailed in 2007 in Los Angeles. This is not the problem we face in cars. In cars, the goal is to reduce the use of fossil fuels, increase fuel mileage and eliminate emissions while creating a vehicle that is as recylicalable as possible. Gasoline over electric is efficient, but so would other configurations, such as diesel over electric, steam over electric, and all-electric. That being said, there have been some very interesting ideas presented here. I, for one, am impressed by this discussion.