Fuel system
of conventional engines, either manifold injection, either direct injection, but regardless of which have their disadvantages. Mixing means for injecting fuel injection system and a direct injection system of the injection manifold injector combination, taking the advantages of both, and weaken the two weaknesses. Not only can improve efficiency of the engine, a direct injection engine is also avoided in the low load operation because of emission problems caused by an excess of oxygen.
1. Term analysis
supply system
of conventional engines, either manifold injection, either direct injection, but regardless of which have their disadvantages. To address rely solely on the direct injection engine technology exists emissions, carbon and other issues, to meet increasingly stringent environmental regulations, jet engine hybrid technology came into being. Mixing means for injecting fuel injection system and a direct injection system of the injection manifold injector combination, taking the advantages of both, and weaken the two weaknesses. Not only can improve efficiency of the engine, a direct injection engine is also avoided in the low load operation because of emission problems caused by an excess of oxygen.
2. lean burn
The mass ratio of combustion in the engine cylinder air-fuel ratio and the fuel is referred to. When just complete combustion of gasoline, which air-fuel ratio of 14.7: 1, this value is referred to the theoretical air-fuel ratio. Lean burn, by definition, that is to say when the fuel in the combustion air is very thin. In the air-fuel ratio greater than 18: 1, the combustion state can be called a lean combustion in the cylinder.
The most important feature is the lean-burn combustion efficiency, while also can improve the economy of the power output of the engine. Because in the lean-burn conditions, under difficult conditions by the theoretical air fuel ratio than the air-fuel mixture ignition, deflagration will occur less readily, so that a higher compression ratio is designed to increase the energy conversion efficiency. Together with the gasoline that burns in an excess of air, so that the support of these conditions can extract all of the energy of each drop of gasoline. However, lean burn is not perfect, it has its flaws. In the case of lean combustion, the exhaust gas will be many residual oxygen, while the temperature of the exhaust gas is low, so that these two reasons catalytic conversion of nitrogen oxides is not high, thus increasing the oxynitride emissions.
is to achieve the best direct-injection lean burn method. When using manifold injection, the upper limit of the air-fuel ratio is 27: 1, while using direct injection, air-fuel ratio even up to 50: 1 or more. Cylinder direct injection engine at low loads, is in the lean burn state, energy efficient, but also more emissions of nitrogen oxides. Meanwhile, in the particulate emissions, due to the short time of mixing oil, forming a larger local area possibility too thick, so the direct injection engine particulate emissions than to manifold injected engines.
3. Mixed injection Introduction
face of increasingly stringent emissions regulations, the direct injection engine is somewhat overwhelming. Thus researchers thought of manifold injector, and to it was added to the direct injection into the engine, the injection system form a set of hybrid.
at low load conditions, when the manifold injector cylinder intake stroke injection, the mixed gas into the cylinder, together with the cylinder during the compression stroke injector nozzle, in order to achieve stratified combustion; high load conditions, direct injection only during the compression stroke. Thus, not only can improve efficiency of the engine, but also to avoid the above-mentioned low load conditions due to emissions caused by an excess of oxygen.
Function
embodiment of the mixing and spray combines the advantages intended manifold injector and in-cylinder direct injection technology to solve the problem of the conventional direct injection technology. Due to the involvement of manifold injection, direct injection engine helps slow down the tradition and the intake valve on the inlet more carbon phenomena.
4. Developing Trend mixed injected
For injection technology in the future development trend of mixing this problem, a number of engine industry experts believe that a major factor in costs or restrict its widespread use. We need to recognize that, although mixed injection technology can solve the traditional direct injection engine problems, but the cost does not have the obvious advantage.
First, since the injection pressure differences between the two systems, which are required for the two ways injection pump and the oil line fitting, the cost is bound to use a higher engine injection mode . Second, the spray pattern of the conversion need to re-make changes to policy control system, what comes next is re-calibration work, which in turn will lead to increased costs.
essence of energy conservation and can not be limited to theoretical data, to focus on the actual performance. Mixed injection mode is not a new technology, it can be seen as the current direct injection engine to solve the traditional drawbacks of a technical means. In the case of the current “super-knock” phenomenon is no clear solutions to be regarded as a technical path, if the problem can be solved, if still mixed injection mode remains to be the test of time.