SE505431C2 - Hybrid drive road vehicle - Google Patents

Abstract

The electric generator both drives the motor and charges the energy- and effect balancing battery. The primary engine effect is suitable via the generator and drive motor to move the vehicle in normal traffic conditions, whilst the battery is used as an addition when a greater energy requirement arises e.g. for faster start, acceleration and reversing and with generative braking from the drive motor. With normal drive conditions, the energy received from the regenerative braking is suitable for charging the battery. The battery is cooled during both charging and discharge by use of Peltier elements, and the primary engine and generator can be replaced by fuel cells or aluminium-air-cells, in which case the Peltier elements are located on the top side of the cells. The battery is sufficiently large to move the vehicle through environmentally sensitive areas without additional power from the generator. The primary drive engine can be a Stiri Otto, Wankel, Diesel, steam or turbine type.

Description

505 431 L: Heat engine and generator can also be replaced with fuel cells. There is also a smaller electric accumulator, which is used as a buffer and which provides an addition to the generator current at start-up, acceleration and extra loads in, for example, uphill slopes.

At normal "cruising speed" the accumulator is not used.

Since the vehicle's kinetic energy has been provided by both the heat engine and the battery's energy, braking with regenerative electric motors can regain more energy than previously taken out of the accumulator. The losses in energy through the efficiency of, among other things, the regenexative braking, the accumulator (with approx. 202 difference in charging and discharging voltage), rolling resistance, etc. determine how to dimension the primary motor, whose emitted energy must correspond to these losses. The primary engine or fuel cells then do not need to be dimensioned to charge the accumulator but only for the average of the power required for the operation of the vehicle and these losses. if the vehicle is moved to a higher location during ex. for 24 hours the accumulator will not be fully charged and may need additional energy from the generator.

The weight and external dimensions of the accumulator should be as small as possible. It is therefore exposed to large loads. ie high currents both when discharging and when charging. The total capacity corresponds, for example, to no more than 5 minutes. discharge.

The prerequisite for this type of operation is therefore that the accumulator is designed for currents corresponding to a car starter battery and in addition is heavily cooled both during discharge and charging.

Example 1.

A bus that weighs 12 tons requires for acceleration to 50 km / h for 10 s an output of 130 kw or an energy of 0.35 kwh. Of this energy, about 300 Wh is kinetic energy, living force, which can be used during deceleration. Assuming that the bus has a primary engine, which including the generator gives 60 kw, 70 kw has been taken out of the accumulator for 10 s or just under 200 Wh. Thus, even with respect to the efficiency of the electric motor generator and the accumulator, the kinetic energy is sufficient to recharge LJ l fl BNSDOCID: .'_ \ _ | 505 431 accumulator.

For this heavy vehicle vehicle, you can choose an accumulator ~ battery whose voltage is 240 V nominal, which if you choose lead batteries corresponds to 120 cells. The average voltage at these high discharges will be about 1.5 V / cell or 180 volts total. At 70 kW load, the current will be closer 600 A. This corresponds to a "heavy duty" diesel starter battery with a weight per 2f volt unit of about 40 kg or a total of about 400 kg. The total discharge time at these high currents is about 9 ~ 6 min and the usable energy content about 6 kwh.

But the size of the battery must of course be adapted to the topography. If the bus needs to take out 70 kwh on an uphill slope, you should keep a third of the energy from a safety point of view, ie only take out 4 kwh. This corresponds to an uphill slope of 4 km at a speed of 60 km / h.

If we assume that the battery's efficiency, internal resistance etc means that a quarter of the maximum power 70 kw must be cooled off and that the battery is in operation S0 Z of the time, then you have to cool off on average maybe 18 kw or 150 W / cell.

Example 2.

A car with a total weight of 700-1000 kg needs 20-30 kw for fast acceleration to 50 km / h for 3-5 s or about 25 Wh. Of this, 6-12 kw comes from the primary engine and generator and 15-20 kW from the battery. But this corresponds to only about 15 Wh and even here the energy in the living power is sufficient to charge the battery without help from the primary motor.

A lead-acid battery for this application may have a rated voltage of 72 volts. This gives a discharge of 300 A. which is normal for a starter battery at a temperature of 30oC and a weight of about 15 kg per 12-volt unit. The total weight of the battery will then be about 90 kg.

To get a good life for the lead-acid battery, it is first required that the charging voltage is limited to 2.35-2.37 V / cell. When the batteries are fully charged, charging stops. The battery should BNSDOCID 505 431 ~ work between 20 ~ 90% of its capacity. At 20 kw load, the losses are about 5 kw and if the batteries are in operation a third of the time, the average energy loss will be 1.7 kw or about SOW / cell.

A condition for this type of operation is that the batteries are cooled, so that the temperature only in exceptional cases exceeds 3000. To get an efficient cooling, you can use the Peltiere effect. because you have electricity available and place the cooling elements exactly where you need them. Cooling can be achieved in various ways, for example according to Swedish patent application 8801318-O, where the negative electrodes are double with a copper foil between them connected to a cooling flange on the top of the lid. He can also use water cooling of the upper part of the electrolyte, which is possible with free electrolyte. If the electrolyte is bound, as is the case in closed cells with oxygen recombination, this latter type of cooling is not always possible for full loads of this stool because the electrolyte does not circulate and the lower part of the cells can overheat.

In these examples, we have counted on the cheaper blv batteries. but of course you can also use more expensive alkaline batteries.

If you have tin vessels and a fatal electrode with a large surface area, for smaller vehicles, forced cooling of the outside of the vessels may be sufficient, but as a rule the battery should be cooled in basically the same way as stated for the lead batteries above.

The range of the vehicle will depend on the amount of fuel you have with you and not on the size of the accumulator. The entrained energy in fuel is up to 100 times greater than the energy in the battery.

Instead of carrying a battery. which for hours should provide energy to the drive motor, you can now manage with a battery that is normally only used for a few seconds or minutes depending on the topography and desired driving characteristics. If the vehicle is to be used mainly in environmentally sensitive areas, the battery capacity can be increased slightly. In this case, the ratio in size between the battery, primary and secondary motors can be changed so that braking does not provide sufficient energy for charging BNSDOCID; un 505 431 batteries without assistance from the primary engine. Also in this case it will be the same hard load on the battery and even if this is to be dimensioned with capacity for 10-15 minutes, cooling is still required during discharge and charging and this is still part of the invention.

The batteries are designed like starter batteries for high currents, but with the emphasis on good life.

The weight and price of the batteries can thus be reduced to a fraction of what is required for battery-powered vehicles.

The system can be used to advantage with a Stirling or a meadow engine, where you can build a closed unit with the primary engine and built-in generators.

In addition, these engines can advantageously use low-emission fuels such as ethanol, natural gas or even hydrogen gas stored in hydrides and completely eliminate the exhaust problem.

The same can be said about fuel cells if and when these have developed and become reliable. But even Otto, Wankel, diesel or turbine engines can be optimized at constant load to provide minimum exhaust gases. The size of the primary engine will only be a fraction of current engines and the total amount of exhaust gas will therefore be correspondingly smaller.

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Claims (3)

G * 505 431 PRENT REQUIREMENTS. 1. l. Hybrid vehicles with a primary motor driving an electric generator, electric motors powered by electric current from the generator and connected to the drive wheels and an energy and power equalizing electric accumulator whereby the primary motor power is sufficient to drive the vehicle in the generator and drive motor. normal traffic while the accumulator is used as an additive when a greater energy need arises, e.g. for faster starting, acceleration and reversing ability and regenerative braking from the drive motor characterized in that the accumulator is designed for high currents and heavily cooled both during charging and discharging and that its capacity is not greater than that under normal operating conditions the energy obtained from the regenerative braking is sufficient to charge the accumulator. Hybrid vehicle according to claim 1, characterized in that the accumulator is large enough to temporarily propel the vehicle through environmentally sensitive areas without addition from the generator. Hybrid vehicle according to one of Claims 1 or 2, characterized in that the primary drive engine is a Stirling, Otto, Wankel diesel, steam or turbine engine, which, regardless of the vehicle's speed, is tuned to provide the best efficiency and a minimum of exhaust gases. . BNSDOCID: