JPS6236141B2 - - Google Patents

Description

Claim 1: A combination combustion engine assembly for a vehicle, comprising a diesel engine 1, a volumetric compressor 5, and a turbine 7, the compressor 5, for example a screw compressor, supplying air to the intake device 2 of the engine. in a combined combustion engine assembly designed to feed the combustion chamber of said engine 1 via said engine 1, said turbine 7 being designed to be driven by exhaust gases from said engine 1;
A mechanical transmission 9 with a fixed gear arrangement interconnects the output shaft 12 of the engine, the compressor shaft 11 and the turbine shaft 10, so that all the air produced by the compressor 5 is transferred to the engine. 1, the turbine 7 is connected to the compressor 5 in the intake device 2 of the engine when the pressure in the exhaust pipe 3 of the engine is operating above at least a certain engine speed and/or load. A combination vehicle combustion engine assembly characterized by exceeding the pressure occupied.

2. In the composite vehicle combustion engine assembly according to claim 1, compressed air from the compressor 5 is supplied to the engine 1 via a supercharged air cooler 6 disposed within the intake device 2. A combination vehicle combustion engine assembly characterized by:

3. In the composite vehicle combustion engine assembly according to claim 1 or 2, the amount of air compressed by the compressor 5 depending on the load applied to the engine 1 and/or the rotational speed of the engine 1. A combustion engine assembly for a hybrid vehicle, characterized in that a valve device 22 adjusts the .

4. In the composite vehicle combustion engine assembly according to claim 3, when the compressor 5 is a screw compressor, the valve device 22
is a sliding valve 23, as known per se, integrated into the screw compressor 5.

5. The combustion engine assembly for a composite vehicle as set forth in claim 4, wherein air that is not compressed in the compressor 5 is returned to the compressor intake port via a return pipe 26. Combustion engine assembly.

6. In the composite vehicle combustion engine assembly according to claim 1, 3 or 5, the gear wheel 19 attached to the turbine shaft 10 is attached to the compressor shaft 11. A combination vehicle combustion engine assembly characterized by direct engagement with a gear wheel 18.

7. In the composite vehicle combustion engine assembly according to claim 6, the compressor shaft 1
The gear wheel 18 on the engine shaft 1 is connected to the engine shaft 1 through the gear wheels 16 and 17 attached to the intermediate shaft 20.
1. A combustion engine assembly for a hybrid vehicle, characterized in that it engages a gear wheel 15 attached to a gear wheel 15 attached to a combustion engine assembly.

8. In the composite vehicle combustion engine assembly according to any one of the preceding claims, the engine 1, the turbine 7, the compressor 5, and the transmission device 9 are arranged so that the engine 1 operates at full load. time, and said engine rotation speed is 600
Combustion engine assembly for a hybrid vehicle, characterized in that said turbines are adapted to each other so as to drive said compressor 5 and also contribute to increasing the output of said assembly when Three-dimensional.

Description The present invention relates to a so-called hybrid combustion engine assembly comprising a diesel engine, a volumetric compressor, and a turbine, where the volumetric compressor, for example a screw compressor, directs air to the intake system of the engine. The turbine is then designed to be driven by the engine's exhaust gases.

In assemblies of this type, it is already known to connect the turbine in a torque-transmitting manner to the compressor via a hydraulic transmission or a mechanical transmission with variable gearing. The compressed air supplied to the engine is adapted with respect to the rotational speed of the engine, such that the supercharged engine corresponds approximately to the maximum power of the engine over a relatively large part of its rotational speed range. Attempts have been made to generate power at high altitudes. In some cases, the turbine operates free-running, ie, without torque-transmitting coupling to the engine.

It is also known to actively control the rotational speed of the turbine with respect to the rotational speed of the engine with mechanical devices. The coupling of the turbine and its engine is in this case adapted such that the turbine is driven over the entire operating range of the engine with an exhaust gas pressure that is less than the intake pressure of the engine. In this way, it is primarily possible to control the diesel engine to operate at maximum efficiency. In this connection, it has been proposed to utilize the energy of the compressed air produced by the compressor, which, when supercharging occurs above a certain pressure value, converts the excess air into the turbine and drives it. It is not used in diesel engines.

However, the above solutions do not significantly improve efficiency compared to conventional diesel engines, and this has proven to increase the complexity of possible assemblies. Moreover, in the solutions already known, the transmission devices used are complex and often involve considerable energy losses.

The invention is based on the problem of creating a combined combustion engine assembly especially intended for vehicles, which combines a diesel engine, a volumetric compressor, an exhaust gas driven turbine and a simple torque transfer transmission. The present invention has a device and allows effective collaboration between the devices incorporated within the assembly, thereby eliminating the drawbacks occurring with known solutions. In this regard, the assembly according to the invention provides that a mechanical transmission with a fixed gear system connects the output shaft of the engine, the compressor shaft and the turbine shaft to each other, and that all the compressed air produced by the compressor is supplied to the engine. and the turbine is designed with respect to the compressor so that the pressure in the engine exhaust pipe exceeds the pressure present in the engine intake pipe at least over a particular engine speed and/or load during operation. Features.

The mechanical transmission with a fixed gear incorporated into the solution advantageously consists of a gear wheel, so that both the engine shaft and the turbine shaft are torque-transmitting connected to the compressor shaft. engine,
The compressor and turbine are then designed to be driven at a constant rotational speed ratio to each other. At low rotational speeds and loads, the engine then drives the compressor without the turbine contributing adequately to it. As the rotational speed of the engine and/or its load increases, the effectiveness of the turbine also increases, and the turbine is configured such that its power output exceeds the power requirements of the compressor even at relatively low rotational speeds and/or low loads. Above this operating point the turbine actively contributes to the total power output of the assembly. Pressure is thereby created on the exhaust side of the engine, which exceeds the pressure on the intake side of the engine. This causes the diesel engine to operate at suboptimal efficiency, resulting in more energy leaving the engine with its exhaust gases. However, within a wide operating range, a decrease in power production from the diesel engine is more than compensated for by an increase in power from the turbine.

In order to obtain a high efficiency of the assembly according to the invention, it is important that all the air compressed in the compressor must be used in the diesel engine. There is therefore no energy available for compressed air that would not be rationally used later in the assembly according to the invention.

In an advantageous embodiment of the invention, the discharge of air from the compressor is controlled by a valve arrangement, which regulates the volume of air drawn into the compressor and compressed. The engine charge can thereby be controlled to provide the assembly with torque characteristics suitable for driving the vehicle. Other significant features of the invention can be found from the following description and claims.

Embodiments of the invention will now be described in detail with reference to the drawing, which diagrammatically shows a combustion engine assembly for driving a heavy vehicle. The assembly has a four-stroke diesel engine 1, which has an intake device 2 and an exhaust device 3. The combustion chamber (not shown) of the engine 1 is supplied with air via an intake device 2, the air is sucked into an air filter 4 and cleaned, then compressed in a volumetric compressor 5, and finally the air is supplied to the engine 1. It is cooled in the supercharger air cooler 6 before being supplied. The exhaust system 3 guides exhaust gas from the diesel engine 1 to a turbine 7, from where the air is guided into the atmosphere via a common exhaust gas extinguisher 8 or the like.

The drive shafts 10, 11, 12 of the turbine 7, the compressor 5 and the diesel engine 1, respectively, are advantageously arranged parallel to each other and are fixed gear devices, i.e. the rotational speeds of the shafts 10, 11, 12 during operation are mutually similar. They are connected by a transmission 9 with a constant ratio device. The transmission device 9 is a gear wheel 15 with ordinary bevel teeth,
Consists of 16, 17, 18, and 19. intermediate shaft 2
The two gear wheels 16 and 17 on 0 are the engine shaft 1
The rotational speed of compressor 2 is changed ten times in two steps, and the compressor 5 is driven via a gear wheel 18 on its drive shaft 11. This compressor gear wheel 18 also engages a gear wheel 19 on the drive shaft 10 of the turbine 7, the gear ratio being made in this case such that the rotational speed of the turbine 7 is 2.5 times the rotational speed of the compressor 5. . Therefore, in the operating state, the gear system operates such that the diesel engine 1 operates at 2000 rpm, the compressor 5 operates at 20000 rpm, and the turbine 7 operates at 2000 rpm.
It can operate at 50,000 times/minute. Obviously other gear ratios can be chosen, but the rotational speeds mentioned above are suitable relative values for this purpose.

The transmission 9 transmits torque in two directions, namely from the engine 1 to the compressor 5 and from the turbine 7 via the compressor 5 to the engine 1. A vibration isolation device 21 is placed in the transmission device 9 between the gear wheels 16, 17 on the intermediate shaft 20, which device can be hydraulic or designed to operate torsionally on the torque transmission shaft. good.

The compressor 5 is advantageously a so-called screw compressor, which provides a predetermined pressure increase independent of the rotational speed. The pressure increase is achieved by a sliding valve 23 built into the compressor 5.
It is controlled by a valve device 22 in the form of . The sliding valve 23 adjusts the amount of air compressed depending on both the load applied to the diesel engine and the rotational speed of the engine. Conditioning is carried out by returning a certain amount of uncompressed air from the compression space of the compressor 5 via the tube 26 to its inlet. In this case, the load and rotational speed of the diesel engine 1 are controlled by the adjustment rod 2.
Approximately indicated by the position 7, this bar supplies fuel to the engine 1 both by actuation by the vehicle driver, such as by the accelerator pedal 28, and by the engine speed sensed by the centrifugal regulator 29. control. In a simple embodiment of the invention, the valve arrangement 22
is placed in the screw compressor 5 and adjusts in one or more stages the amount of air drawn in for compression according to a specific predetermined value for the load and rotational speed of the engine. It can be constructed with a sliding valve known per se.

A screw compressor 5 adapted to a diesel engine 1 can advantageously provide a final pressure of the order of 2.5-3 bar (2.5-3.10 ⁵ Pascals). The air heated during compression is cooled in a charge air cooler 6 before it is supplied to the diesel engine 1. In existing equipment, the cooling effect can be between 50-100°C depending on the cooling device used.

The diesel engine 1 as a whole operates advantageously without valve overlap or possibly with very little valve overlap, ie the exhaust gas valve closes before or at least immediately after the inlet valve opens. The engine 1 is thereby able to generate a higher pressure on the exhaust gas side than on the intake side. In the present case, the exhaust gas system 3 and the turbine 7 installed therein have a pressure of 4 bar (4.10 ⁵ Pascals) at full power point, i.e. in the operating state in which the engine 1 produces maximum power.
is chosen such that an exhaust gas pressure in the region of .

The exhaust gas energy is converted into mechanical power in the turbine 7 by expansion of the exhaust gas. The pressure level of the exhaust gas therefore falls to a value just above atmospheric pressure, and the exhaust gas temperature simultaneously decreases to about 250
℃, so after turbine 7
The temperature will be around 450℃.

The efficiency level of the turbine 7 will be 80-85%, which is within the normal operating range for a combustion engine assembly. Supercharged diesel engines designed for vehicles can achieve efficiency levels of approximately 37% at their full power point. It is assumed here that the engine operates at a higher intake pressure than the exhaust pressure. If this relationship is reversed, ie, if the exhaust gas pressure of the diesel engine is greater than the intake pressure, which is the case in the present invention, the efficiency level of the diesel engine decreases. However, the turbine 7 uses the increased energy content of the exhaust gas due to the increased exhaust gas pressure and transmits this in the form of mechanical power to the output shaft 12 of the assembly. This compensates for the loss in efficiency and the reduction in power output experienced by the diesel engine 1 due to the increase in exhaust gas pressure. The maximum efficiency of the assembly at full power operation can instead be increased by as much as 10% to about 41%. At said operating point, the compressor 5 is designed to operate at an efficiency level of approximately 80%, and the efficiency level of the transmission is in this case 94%.

Assemblies designed for vehicle drives are advantageously designed to operate at maximum efficiency at engine speeds lower than those encountered at full power. A truly optimal diesel engine for a vehicle can achieve an operating efficiency of about 40% at the rotational speed where maximum torque is produced. Within a range around said rotational speeds, the overall efficiency level of the assembly according to the invention can be achieved to correspondingly higher values.

Moreover, the overall efficiency level of the assembly can be increased by 6-7% if cooling losses in the diesel engine can be kept low. This can be conveniently achieved through the use of heat-resistant materials, with which exhaust gas temperatures can be reached as high as 1000°C, which significantly reduces the energy content in the exhaust gas that can be used by the turbine. It means to increase.

The fact that the screw compressor 5 is directly driven by the diesel engine 1 makes it possible to achieve efficient engine supercharging even at low engine speeds. In this case, the compressor 5 is designed to operate at its best efficiency level at rotational speeds in the middle of the rotational speed range used to drive the vehicle. For diesel engine 1 used as an example, the rotational speed range is 1000 rpm to 2000 rpm.
Between the minutes. The turbine 7 incorporated into the assembly allows it to both drive the compressor 5 at full engine load and at rotational speeds of more than 600 rpm and contribute to increasing the power output of the assembly. . A desirable increase in torque production in the drive assembly within the vehicle at low rotational speeds is thereby achieved. However, at high engine loads the contribution of the turbine 7 to the output of the assembly is
It is clear that the entire rotational speed range of the engine 1 is covered. Furthermore, with the aid of the valve arrangement 22, the supercharging can be controlled such that the torque production increases with decreasing rotational speed, which reduces the need for gear changes when driving the vehicle, e.g. do. Said valve arrangement 22 also controls the supercharging of the engine 1, so that this decreases with decreasing load. In this way, the engine 1 does not receive an unnecessary amount of compressed air when operating under partial load;
And it is inter alia ensured that the assembly does not have to release power for producing said air. At low loads and low rotational speeds, the turbine 7 does not produce any useful power, and only at 1200 rpm, for example, can the turbine 7 drive the compressor, so that at high rotational speeds and a constant load the compressor This results in only a slight addition to the output of the assembly.

The invention is not limited to the embodiments described above, as it can be modified in various ways within the scope of the appended claims.