Publication Date: 2005-Jul-15
The IP.com Prior Art Database
This new technique refers to the ventilation of crankcase gases from the crankcase of a combustion engine not to the inlet system of the engine but to the exhaust system of the engine. The crankcase gases are conveyed from crankcase to an exhaust gas pipe of the exhaust system via a crankcase gas conduit. The crankcase gas conduit is connected to the exhaust gas pipe upstream an exhaust gas after treatment equipment. An exhaust gas after treatment equipment in the exhaust gas pipe will not only remove polluting elements in the exhaust gases from the engine but will also remove polluting elements in the crankcase gases. The crankcase gas conduit includes a cleaning device for cleaning the crankcase gases and for separating oil from the crank case gases before they reach the exhaust system. Means are provided for forcing the crankcase gases into the exhaust gas pipe. The forcing means may include an ejector, a venturi or a pump for forcing the crankcase gases from the crankcase through the crankcase conduit and into the exhaust gas pipe.
It is known to ventilate crankcase gases from a combustion engine to the engine inlet system. This causes problems with dirt such as oil and exhaust deposits contained in the crankcase gases. The dirt may get caught by the components in the inlet system, for instance the air filter, the compressor, the inter-cooler, the inlet manifold, the piping and inlet channels, and the inlet valves. There is also a risk of the engine not being controllable in a proper manner, when too much oil or fuel find its way through the crankcase ventilation system.
This new technique aims at overcoming these problems. Basically the new technique proposes to convey the crankcase gases not to the inlet system but to the exhaust system of the engine, see US Patent 4,827,715 and US Patent 6,588,201. Two problems are still connected to the known technique, which does not ensure a reliable supply of the crankcase gases to the exhaust system since the static pressure in the crankcase may be lower than the static pressure in the exhaust system. Furthermore, the known technique will also lead to an increase of polluting hydrocarbon elements in the gases leaving the exhaust system to the surrounding atmosphere.
The new technique is illustrated in the attached Figs 1 – 3. Fig 1 shows schematically a combustion engine 1, for instance a diesel engine, having an inlet system 2 and an exhaust system with an exhaust gas pipe 3. The inlet system includes an air filter 21, a compressor C and an inlet line 22 for leading the inlet air to the engine 1. The exhaust system includes an exhaust turbine T, which together with the compressor C are parts of a turbo charger, an exhaust brake 4 and an exhaust gas after treatment equipment 5. According to this new technique the crankcase gases are conveyed from the crankcase of the combustion engine 1 the to the exhaust gas pipe 3 of the exhaust system via a crankcase gas conduit 6. The crankcase gas conduit 6 is connected to the exhaust gas pipe 3 at a connection A upstream the exhaust gas after treatment equipment 5. The exhaust gas after treatment equipment 5 may include oxidation catalysts, diesel particle filters or the like. This equipment 5 will remove polluting elements and oxidise hydrocarbons contained in the crankcase gases.
The crankcase gas conduit 6 includes a cleaning device 7 for cleaning the crankcase gases and for separating oil from the crankcase gases before they reach the exhaust system. The separated oil may then be returned to the oil system of the engine 1 in a manner known per se. The cleaning device 7, which is also known per se, may include a filter, a cyclone, a centrifugal separator etc. B...