Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Patent
1987-03-25
1988-11-01
Koozo, Michael
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
60606, 123179F, F02B 3700
Patent
active
047810289
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a diesel engine, in particular an aircraft engine, with an exhaust gas turbocharger.
In such diesel engines, the turbocharger ensures the corresponding air charge supply (in a four-cycle diesel engine) or scavenging air supply (in a two-cycle diesel engine) during normal operation. What is problematic is in particular the starting phase, in which the turbine of the turbocharger is subjected either not at all or only slightly to the exhaust gases of the engine. In order to provide the pressure condition necessary for starting, a two-cycle diesel engine can only be started at all after the turbocharger has already been set to work. In the case of a four-cycle diesel engine the turbo effect is delayed. For these reasons the turbocharger is generally run up, before the engine is started, with the aid of foreign energy, e.g. with the aid of a hydraulic motor or a high-speed electromotor or with compressed air; cf. for example German patent No. 490 736.
All these known constructions are quite elaborate and increase the weight and overall size of the engine. This is in particular disadvantageous for aircraft engines, whose weight and overall size should be as small as possible.
The invention is based on the problem of starting a diesel engine of the type in question in which the turbocharger can already be run up during the starting phase with little effort.
This problem is solved by the present invention.
Thus, to start the diesel engine a compressed air starter is used whose exhaust air is utilized in two ways during the starting phase. Firstly, the engine is supplied through the compressed air with sufficient boost pressure or sufficient scavenging air; secondly, the turbocharger is run up at the same time. Using the measure according to the invention, diesel engines can be designed with a lower pressure ratio or compression than up to now. The compression ratio of approx. 23:1 as customary up to now is necessary essentially only for the starting phase, in order to supply the diesel engine with sufficient air charge or scavenging air, whereas a much lower value of approx. 13:1 is sufficient for the normal operating range.
Compressed air starters for diesel engines are known as such, in particular in connection with marine engines or engines for diesel locomotives, in which no special attention must be paid to the overall size. However, in these cases the inventive principle is not exploited.
A construction according to the invention makes it possible to start the engine with compressed air alone, to supply sufficient air charge or scavenging air during the starting phase and at the same time to run up the turbocharger. The only source of energy is, for example, a small compressed air cylinder for the compressed air starter.
With such a construction, a two-cycle diesel engine can start up without the turbocharger being run up by a separate source of energy before the starting. A four-cycle diesel engine runs up much faster than usual with a construction according to the invention.
The exhaust air normally blown off by compressed air starters without being used further is preferably directed to the compressor side of the turbocharger. This can bring the turbocharger to the operating speed particularly fast. It is also possible to supply the exhaust air from the compressed air starter to the turbine of the turbocharger, that is otherwise subjected to the exhaust gases of the engine. This also runs the turbocharger up to the operating speed relatively fast.
If the exhaust air from the compressed air starter is supplied to the compressor side of the turbocharger and then directed into the engine, it is possible to mix with this compressed air stream an additive that increases the ignition performance of the diesel engine. This admixture takes place only during the starting phase and is controlled via the compressed air starter or via its exhaust air. Such an additive is, for example, kerobrisol, of which only small amounts, e.g. 0.5 cm.sup.3, are admixed at each starting. This incre
REFERENCES:
patent: 1893127 (1933-01-01), Buchi
patent: 2176021 (1939-10-01), Grutzner
patent: 2974659 (1961-03-01), Wilson
patent: 4232521 (1980-11-01), Mallofre
LandOfFree
Turbocharged diesel engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Turbocharged diesel engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Turbocharged diesel engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-883825