RU2349782C2 - Diesel engine with inlet and outlet circuits connected by crossover pipe - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: diesel comprises inlet and outlet circuits connected by crossover pipe. In the area of crossover pipe connection to outlet circuit there is a movable gate valve, and extent of its opening is specified by operator's command or automation system signal. Extent of gate valve opening provides continuous uninterrupted operation of diesel engine in idle running condition and at low loads with maintenance of exhaust gases temperature of at least 250° C.

EFFECT: prevention of unburnt oil exhaust from outlet circuit, worsening of ecological situation near operating diesel engine and coking of turbocompressor flow path.

1 dwg

Description

The invention relates to diesel engineering and applies to two and four stroke diesel engines.

In recent years, in a number of branches of technology and the national economy (marine and river fleets for various purposes, diesel locomotive, backup and emergency diesel power units and power plants, etc.), the demand for diesels that allow continuous continuous operation at low loads (from idling and usually up to 25% - further fractional modes) without time limit.

The solution to this problem is hindered primarily by the release of unburned oil into the exhaust system of the engine and from it into the environment, which significantly worsens the environmental situation near the working engine. In addition, in these modes, coking of the turbine compressor turbine compressor (TC) turbine flow section occurs, which makes it impossible to bring the engine from shared loads to a predetermined higher one due to the occurrence of surging TC, i.e. leads to the impossibility of normal operation of the engine. These troubles are due to the low temperature of the exhaust gases in these shared modes.

To avoid the noted troubles, all diesel-building companies are usually forced to prescribe in their operating instructions periodic (every 5-10 hours of operation in such modes) engine output to increased loads (more than 50%) to burn the exhaust manifold and the flow part of the fuel oil from unburned oil and coke deposits. Obviously, the implementation of this requirement creates significant inconvenience for consumers and in some cases leads to significant additional costs for them.

Patent No. 2285133 proposes the use of modified gas distribution bodies to ensure long-term continuous operation of a diesel engine at shared loads. This solution proposes another way to achieve a similar result - increasing the temperature of the exhaust gases to the required values due to the partial bypass of the exhaust gases to the intake and thereby increasing the temperature of the fresh charge at the inlet to the diesel cylinders.

An object of the invention is the application of such a solution that would ensure both normal operation of the diesel engine at all operating conditions and continuous operation without idle time and idle and low loads - usually less than 25% - (fractional modes) by increasing the temperature of the exhaust gases to a level at which the release of unburned oil from the cylinders into the exhaust path and out and the coking of the turbine compressor turbine flow section is usually up to a level of at least 250 ° C. The problem is solved through the use of diesels containing an inlet (intake) and exhaust paths interconnected by a bypass pipe, and in the area where the bypass pipe is connected to the exhaust duct, a movable damper is installed, characterized in that the degree of opening of the damper is set by the operator or automation system to ensure long continuous idle operation of the diesel engine and low loads while maintaining the temperature of the exhaust gases in these modes at least 250 ° C due to the bypass part accelerated gases to suction.

An increase in the temperature of exhaust gases in fractional modes is ensured by increasing the temperature of the fresh charge at the inlet to the diesel cylinders due to the partial mixing of the intake air with the exhaust gases transferred to the diesel inlet (or its charge unit - turbocharger compressor). Depending on the type of diesel engine and its characteristics, a bypass, usually not more than 60% of the exhaust gases, may be required. Since exhaust gases in fractional modes have a sufficiently large excess of air, the normal operation of the diesel engine under these conditions is ensured. With this organization of the working process, the temperature of the charge at the inlet to the cylinders can reach 160-180 ° C, and at the inlet to the boost unit it can be slightly less than the indicated values.

When implementing this solution on the engine, the compressor part of the boost unit, as well as the charge air receiver and the blow-off window area of a two-stroke diesel engine must be structurally adapted to work with the indicated temperatures. In addition, when switching on the exhaust gas bypass, it is necessary to provide for the shutdown of the cold water flow through the diesel air cooler to eliminate unnecessary cooling of the air in this case. If there is a dual air cooler on the engine - an air heater, one of the sections of which is a cooler and is washed by the water of the external circuit, and the other by a heater washed by the hot water of the internal circuit of the engine, the flow through this second section is maintained when the exhaust gases are bypassed.

To organize the bypass of the exhaust gases for suction, a movable damper is installed in the zone where the bypass pipe is connected to the exhaust duct, which is controlled automatically or by command of the operator. Two control options (automatic regulation) can be realized by opening the damper - full opening and complete closure, or opening the damper proportional to the number of exhaust gases transferred to the suction. In the first case, the simplest automation or control system for the damper is implemented - when the exhaust gas temperature drops below a predetermined level (less than 250 ° C), the damper opens completely. In this case, in a mode with a temperature close to 250 ° C, the temperature will increase to 400-420 ° C. With a further decrease in load up to idling, the temperature will decrease, always remaining above 250 ° C. In the second case, at any fractional mode, the temperature of the exhaust gases will be maintained approximately constant in the range of 275-290 ° С

Opening the shutter at an exhaust gas temperature below 250 ° C is time-delayed depending on the setpoint for this type of engine and its operating conditions. The required cover of the shutter when the temperature of the exhaust gas rises above 300-350 ° C or 400-420 ° C (depending on the adopted law of control of the shutter) should be implemented without delay in time. The value of the time delay for the issuance of a control signal is set by the person responsible for the operation of this engine, in accordance with the instruction manual of the latter and is implemented either by the operator (with manual control), or by using the regulatory body of the automation system.

The drawing shows a diesel engine with inlet and outlet tracts interconnected bypass pipe. Here 1 is a diesel engine, 2 is a turbocharger, 3 is an exhaust tract, 4 is a damper lever, 5 is a damper, 6 is an overflow pipe, 7 is an intake duct.

When operating in modes with an exhaust gas temperature above 250 ° C, the shutter is closed. When operating in shared modes (with the temperature of the exhaust gases below 250 ° C), the operator or the automation system, acting on the lever 5, open the valve 6 to the required value in accordance with the implemented control procedures for it, mentioned above. With an increase in the diesel load and a corresponding increase in the temperature of the exhaust gases, the shutter is closed. The degree of opening of the damper determines the amount of exhaust gases that are allowed to be sucked in. To protect soot and scale from getting into the suction from the exhaust pipe, a strainer is recommended to be installed on the overflow pipe.

Claims (1)

A diesel engine comprising an inlet (intake) and exhaust ducts interconnected by a bypass pipe, wherein a movable damper is installed in the area where the bypass pipe is connected to the exhaust duct, characterized in that the degree of opening of the damper to provide continuous continuous idling of the diesel engine and low loads with maintaining the temperature of the exhaust gases in these modes at least 250 ° C is set by a team of operators or automation systems.