Internal-combustion engines – Charge forming device – Heating of combustible mixture
Patent
1999-04-08
2000-05-30
McMahon, Marguerite
Internal-combustion engines
Charge forming device
Heating of combustible mixture
123557, 123575, F02M 3100
Patent
active
060679727
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a fuel injection device for an internal combustion engine according to the preamble of claim 1.
BACKGROUND OF THE INVENTION
Such a fuel injection device is generally known in the prior art. For example, an injection system for LPG is being marketed by Applicant under the name of LPI. The LPG in this case is in a liquid state during the injection and is not converted to vapour form until it is in the intake duct. Such a system has many advantages, such as negligible loss of power compared with petrol as the fuel, accurate metering possibilities and simple connection to electronics of electrically controlled petrol injection systems.
In order to ensure that the LPG used remains in the liquid state, a pump for increasing the pressure is used. Numerous measures are also taken to prevent heat transfer as much as possible from parts of the internal combustion engine to the supply/discharge pipes or injectors. The result of this is that liquid LPG can be guaranteed to be present in the injectors in all operating circumstances.
It has been found that injectors used inevitably show some leakage. This means that after the internal combustion engine has been switched off fuel goes into the intake manifold and makes starting more difficult. For the first part of the mixture which has been drawn in will contain excess fuel and ignite poorly, which gives rise to a risk of the spark plugs becoming fouled. This problem is particularly prevalent if the starting-up is on petrol. For during the first starting revolutions an excess of a mixture of vaporized LPG and petrol will be present, with the result that the petrol could well become deposited on the electrodes of the spark plugs.
This effect is a particular nuisance if the internal combustion engine is started up again a short time after being switched off. For if a longer period is allowed to elapse, the gaseous LPG will leak out of the system through the outlet or through other cylinders.
European Application 0,178,484 discloses an internal combustion engine which can run both on gas and on petrol. In this case LPG is introduced into the internal combustion engine in the liquid state.
U.S. Pat. No. 5,159,915 discloses an injector provided with a heating element. This injector is designed exclusively for running on petrol.
BRIEF SUMMARY OF THE INVENTION
It is the object of the present invention to provide a simple way of avoiding as far as possible the effect of leakage from the injectors for injecting liquid gas.
The invention is based on the idea that liquid will always leak on account of the fact that the injector always leaks slightly because of the optimum insulation and the increased pressure inside the injection system. This liquid (liquid LPG) expands by approximately a factor of 250. This means that the effect of the leakage is increased by a factor of 250. If the supply pipe is now heated during the switching-off, the liquid will pass into the vapour phase and most of it will be returned to the tank, and with the same leakage from the injector concerned 250 times less fuel will go into the cylinder. It has been found that starting problems then no longer occur.
Although the invention has been described above with reference to an LPG-driven engine, it should be understood that this principle can be used for any fuel which is relatively simple to convert from liquid phase to vapour phase. An example of the above is DME (dimethyl ether).
The supply pipes can be heated in any conceivable way. A particularly simple solution with the use of flexible pipes in particular is to have integrated therein an electric resistance heating coil. Its heating can be governed by a control mechanism. The injection system for the fuel such as LPG need not be changed any further.
With the design described above, only gaseous LPG will still be present in the pipes some time after the internal combustion engine has been switched off. It is not uncommon for such internal combustion engines to be started on petrol as indicat
REFERENCES:
patent: 3999525 (1976-12-01), Stumpp et al.
patent: 4898142 (1990-02-01), Van Wechem et al.
patent: 5054458 (1991-10-01), Wechem et al.
patent: 5284117 (1994-02-01), Akase
patent: 5850822 (1998-12-01), Romann et al.
patent: 5873354 (1999-02-01), Krohn et al.
patent: 5894832 (1999-05-01), Nogi et al.
McMahon Marguerite
Vialle B.V.
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