FR2934931A1 - System i.e. electric generating set, for recharging motor vehicle battery, has electric generator connected to heat engine to transform energy into electric energy and placed on path of air stream supplying engine for cooling - Google Patents

Abstract

The system has an electric generator (1) connected to a heat engine (2) e.g. Otto-cycle petrol engine, for transforming energy received from the heat engine into electric energy. Air inlet (3) supplies air to the thermal engine. The electric generator is placed on a path of air stream (12) supplying air to the thermal engine for cooling. Fuel injection device injects fuel on winding overhang (6) of the generator. Water injection device injects water on the overhand of the generator. The generator is placed on the air stream in upstream or in downstream of super charger.

Description

The invention relates to a system comprising a heat engine and an electric generator, such as a generator or a propulsion engine. It also relates to a motor vehicle equipped with such a system.

A generator consists of a heat engine and an electric machine operating as a generator. The heat engine generates a power that is transmitted in mechanical form to the generator that produces electrical energy. These two components must be cooled in order to evacuate losses.

To implement this cooling, a first solution is to use a cooling device based on water or oil as a cooling fluid. Such a device is however complex and expensive due to the following constraints: - there are risks of leakage of the fluid circuit; -This device requires a pump, a thick housing and dedicated to cooling, -the temperature of the water or oil is often much higher than that allowed for an electric machine because of the engine, -the oil of the The heat engine may contain metallic or even ferromagnetic particles, the presence of which is detrimental to the electric motor.

A second solution is to cool the heat engine by a flow of air, which imposes a coolant circuit only for the generator. Solutions exploiting this approach, such as that described in EP1296039, use a fan to set the air in motion, which decreases the efficiency of the generator as some of its energy is absorbed by the fan. In addition, air has a more limited cooling capacity than water or oil due to its low heat capacity. The solutions of the state of the art are therefore not satisfactory and there is a need for another solution for cooling the components of a generator, and more generally of a system coupling a heat engine to an electric generator. Thus, a first object of the invention is to provide a high-performance cooling solution.

A second object of the invention is to provide an inexpensive cooling solution.

For this purpose, the invention is based on a system comprising an electric generator connected to a heat engine for converting the energy received from the heat engine into electrical energy, comprising an air inlet for supplying the heat engine, characterized in that the electric generator is arranged in the path of the supply air flow of the heat engine to be cooled by this air flow.

The system may include a fuel injection device on coil heads of the electric generator.

It may alternatively comprise a device for injecting water onto the coil heads of the electric generator. The electric generator may be placed on the air stream upstream or downstream of a supercharger.

The electrical generator may comprise at least one package of sheets with windings on teeth or pins.

The electrical generator may comprise at least one sheet package separated in several parts by separators.

The previous system can be a generator or a propulsion engine.

The engine may be an Otto cycle engine ("gasoline") or diesel cycle or Rankine cycle or Brayton cycle (gas turbine, reactor) or Ericsson cycle or Stirling cycle or a battery fuel.

Finally, the invention also relates to a motor vehicle characterized in that it comprises a system as described above. The system can thus be a generator for recharging at least one battery of the motor vehicle.

These objects, features and advantages of the present invention will be set forth in detail in the following description of a particular embodiment made in a non-limiting manner in relation to the appended figures among which:

Figure 1 shows schematically a generator according to the invention; FIG. 2 diagrammatically represents a first variant embodiment of the embodiment of the invention; FIG. 3 diagrammatically represents a second variant embodiment of the embodiment of the invention; FIG. 4 diagrammatically represents a third variant embodiment of the embodiment of the invention; FIG. 5 represents a detail of a winding of the electric generator according to the embodiment of the invention; FIG. 6 represents a variant of the winding of the electric generator according to the embodiment of the invention; FIG. 7 represents a detail of a sheet packet of the electric generator according to the embodiment of the invention; FIG. 8 represents a cross-sectional view of the electric generator sheet pack according to the embodiment of the invention; Figure 9 shows a longitudinal sectional view of the electric generator sheet package according to the embodiment of the invention.

FIG. 1 schematically represents a generator comprising a generator 1 and a heat engine 2. The heat engine is supplied with air coming from an air inlet 3. The incoming air then passes through an air filter 4, then the generator 1 before reaching the intake manifold 5 of the heat engine 2. The generator 1 comprises on the one hand coil heads 6 and on the other hand sheet packs 7.

The concept of the invention consists in arranging the generator 1 in the supply air flow of the engine 2, so as to cool this generator. This solution avoids the use of a fan to put a flow of cooling air moving, which is advantageous in terms of its performance.

A first alternative embodiment is shown in Figure 2. It consists in providing a fuel injection circuit 8 so as to spray fuel at the coil heads 6. This solution makes it possible to evaporate the fuel on the heads of coil. This phase change of the fuel absorbs significant energy from the heat generated by the generator 1 at the coil heads 6, thus inducing a strong cooling of the generator. This solution is carried out at low temperature and also provides an effective mixture between the gasified fuel and air, which is advantageous before the mixture access to the engine. This solution is particularly advantageous for fuels with high boiling temperature and / or for periods of extreme cold. Note that this variant does not apply to a diesel engine for which the fuel is mixed with air only in the cylinder.

It is also possible to spray water on the coil heads 6, which may have the advantage of cooling the mixture during compression, which increases the efficiency of the engine. This solution is particularly advantageous for supercharged engines, whether petrol or diesel.

The generator may be placed before or after the compressor 9, according to two embodiments respectively illustrated by FIGS. 3 and 4. In the first variant, the air flow 12 passing through the generator 1 is hotter, which reduces a little the efficiency of the cooling, but the evacuated heat participates in a positive way to the creation of engine work. The efficiency of the system is improved. Figure 4 shows the generator 1 positioned upstream of the compressor 9 in the path of the air flow 12 of the engine intake. In this second variant, the air cooling the generator is cool but the heat evacuated increases the temperature of the air and requires a higher compression work or reduces the density of the air output of the compressor 9. two embodiments are compatible with the use of a turbocharger.

The electric generator 1 may have certain advantageous configurations to fulfill the dual function of promoting its cooling by the air flow 12 and not to disturb too much this air flow.

Figure 5 shows a first interesting embodiment comprising a winding on teeth. This geometry offers a space between the coils where the flow of air can pass. FIG. 6 represents a second interesting embodiment based on soldered pin coils, which promote heat exchange with the air flow.

In addition, the generator sheet package, for the stator and / or the rotor, may have a structure in several parts separated by separators 11, as illustrated in FIG. 7. The air flow 12 passes through this structure through separating spaces 11. FIG. 8 illustrates a section in a transverse plane, perpendicular to the longitudinal direction x, while FIG. 9 illustrates a section in a longitudinal median plane of such a solution. According to another variant embodiment, the rotor can be twisted and its notches can serve as a turbine for pumping a little more air into the intake manifold.

The invention can be applied to any system combining a heat engine and an electromechanical generator, whether a generator or a propulsion engine. It is compatible with all engines, including: - Otto gasoline cycle - Diesel cycle - Rankine cycle (steam) - Brayton cycle (gas turbine reactor) - Ericsson cycle - Stirling cycle - fuel cells.

The invention can be applied to any combination of a heat engine (in the thermodynamic sense of the term) and a generator such as: gas turbines and reaction reactor; gas and combined cycle turbines for generating and co-generating electrical energy; automotive alternators.

It can be implemented within a motor vehicle, in particular for a generator for recharging the battery of a motor vehicle.

Claims (10)

Revendications1. System comprising an electric generator (1) connected to a heat engine (2) for converting the energy received from the heat engine into electrical energy, comprising an air inlet (3) for supplying the heat engine (2), characterized in that the electric generator (1) is arranged in the path of the air flow (12) for supplying the heat engine (2) in order to be cooled by this air flow. 2. System according to claim 1, characterized in that it comprises a fuel injection device (8) on coil heads (6) of the electric generator (1). 3. System according to claim 1, characterized in that it comprises a water injection device on coil heads (6) of the electric generator (1). 4. System according to one of the preceding claims, characterized in that the electric generator (1) is disposed on the air flow (12) upstream or downstream of a supercharger (9). 5. System according to one of the preceding claims, characterized in that the electric generator (1) comprises at least one package of sheets with winding teeth or pins. 6. System according to one of the preceding claims, characterized in that the electric generator (1) comprises at least one sheet package (7) separated into several parts (10) by separators (11). 7. System according to one of the preceding claims, characterized in that it is a generator or a propulsion engine. 8. System according to one of the preceding claims, characterized in that the engine (2) is a cycle engine Otto ("gasoline") or diesel cycle or Rankine cycle or Brayton cycle (turbine to gas, reactor) or Ericsson cycle or Stirling cycle or a fuel cell. 9. Motor vehicle characterized in that it comprises a system according to one of the preceding claims. 10. Motor vehicle according to the preceding claim, characterized in that the system is a generator for recharging at least one battery of the motor vehicle.