DE2537076A1 - GASOLINE COMBUSTION ENGINE - Google Patents

Description

PATENT ADVOCATE DR. CLAUS REINLÄNDER DIPL.-ING. KLAUS BERNHARDT

D-8 Munich 60 · Orthstraüe 12 ■ Telephone (089) 832024/5 Telex 5212744 Telegrams Interpatent

269/5

Fuji Heavy Industries Ltd.

7-2, Nishishinjuku 1-chome Shinjuku-ku, Tokyo, Japan

Internal combustion engine powered by gasoline

Priority: September 12, 197 ^ Japan 105360 / 74-

Short excerpt

A gasoline-powered internal combustion engine includes a combined setting for the ignition timing to keep the temperature of the combustion gas below 2000 ⁰ C during the combustion process, a heat build-up device that extends from the seat of an exhaust valve to the exit of an exhaust port, and heat insulation to to thermally isolate an exhaust system, whereby the temperature of the exhaust gas is maintained above 750 C within the exhaust duct which connects to the exhaust valve which has a volume which corresponds approximately to the cylinder volume of the engine.

The invention relates to a gasoline internal combustion engine to reduce the impurities in the exhaust gas to a predetermined level.

Many exhaust emission control devices have been developed to meet stringent emissions regulations. These known devices can generally be classified into two categories. at

6Ü9813 / 0664

one the machine body itself is modified to accommodate the purify toxic exhaust gas. In the other, the exhaust gas is used for purification in the exhaust system that is connected to connects the machine body, treated. The stratified combustion system, in which a combustion chamber is provided with another combustion chamber to the former category. The latter category of conventional exhaust emission control devices includes, for example an exhaust emission control in which a device for further burning the toxic exhaust gas in the Exhaust system is provided, and an arrangement in which a catalytic conversion system to assist the Purification of the exhaust gas is additionally provided in the exhaust system.

The stratified combustion system is in the construction of the machine complicated because an additional combustion chamber and an inlet valve are provided and because the control of the Mixing ratio is difficult because of the layered supply. This system is disadvantageous because it is difficult is the necessary reliability in operation and control in comparison with a known system to maintain, which is why special maintenance is required.

The exhaust emission control device of the latter type, which includes a thermal reactor or a catalytic device has several disadvantages. If the machine ignites incorrectly, there will be an abnormal rise in temperature resulting in a possible fire in the vehicle. Therefore, a very precise safety device must be used to be built in. Furthermore, this system is large and complicated in structure and requires heat-resistant ones Materials and precious metals for their manufacture. Therefore, the manufacturing cost is very high. In addition, can result in a secondary environmental nuisance although the system is effective in being a primary environmental nuisance; *

bU96 1 3/0664

. 3- 2537078

prevented. In addition, the system requires periodic maintenance and replacement of parts. Especially in the case of the catalytic converter system, a special fuel (unleaded gasoline) must be used, and if so the machine is not sufficiently heated, no reduction in the impurities in the exhaust gas is effected, rather, the toxic gases can even increase.

Ks is known that the constituents of the outlet gas influenced by various factors for controlling the operation of the engine, e.g. the shape of the combustion chamber, the carburetors, the ignition timing, the timing valve actuation or heat build-up in the outlet lines. Many exhaust emission control devices installed on one based on these factors have been suggested. However, these devices become like an auxiliary device too used the above-mentioned system and have not yet had satisfactory results in reducing the Result in impurities in the outlet gas.

The object of the invention is to create a gasoline-powered internal combustion engine that is shown in is able to reduce the impurities in the outlet gas to a predetermined level, the Machine a systematic combination of the machine control factors mentioned above without using a additional combustion chamber and a modification of the machine structure.

The engine is also intended to be an exhaust emission control device for gasoline-powered internal combustion engines that is simply constructed by adding the Exhaust system is changed for a heat build-up, without an afterburning chamber or a catalytic converter.

According to the invention is a gasoline powered internal combustion engine provided that in combination a

fc U 9 8 1 3/0 B 6 L

253707B

-If ".

Adjustment of the ignition timing, a heat accumulation wall that

itself, extends from the seat of the exhaust valve to the outlet port, and includes a heat insulation which is provided at the Auslaßrohrsystera, whereby the combustion gas temperature is maintained below 2000 ⁰ G when the combustion progresses, and the outlet gas temperature above 75O ⁰ C to the volume of the exhaust passage following the exhaust valve, which corresponds to the engine cylinder volume.

The invention is described by way of example with reference to the drawing in which

i'ig. 1 is a partially sectioned side view of FIG gasoline-powered internal combustion engine according to the invention,

Fig. 2 is a cross-section along the line 11-11 in Fig. 1,

Fig. 3 is a graph for explaining the Relationship between the concentrations of the impurities in the outlet gas and the air-fuel ratio,

Fig. 4 is a graph showing the relationship between the concentration of nitrogen oxides in the outlet gas and the stroke-to-bore ratio and

Figure 5 is a graph of outlet temperature depending on the difference in the ignition timing.

It has been confirmed through experiments that the combustion gas temperature and the exhaust gas temperature are essential to be considered for the removal of the impurities from the exhaust gas. For example, nitrogen oxides are generally produced at high temperature and foxyden the ratio of the rising amount of the products of Stickstof increases sharply at about 1800 ⁰ C. Carbon monoxide and hydrocarbons tend to react by themselves when the outlet gas temperature reaches a predetermined level

6U981 3/0664

- if "

achieved. Such a temperature that triggers the self-reaction is around 750 C.

With these facts in mind, it can be seen from Fig. 5 that a known machine is completely ineffective in reducing impurities in an exhaust gas. As indicated by dashed lines in Fig. 5, the combustion gas temperature is far above 2000 ⁰ C and then a \ if reduced 1000 ⁰ G to 1200 ° C, while the temperature in the gas discharged into the outlet port via the outlet valve is further reduced to 35O ° C to 800 ⁰ C. The amount of nitrogen oxides produced is thus very large because of the high combustion temperature, and an unclean exhaust gas containing carbon monoxide and hydrocarbons is discharged to the outside because the temperature of the gas discharged to the exhaust system suddenly falls below the temperature for triggering the self-reaction.

Further attempts have the facts shown in FIG confirmed. First of all, the impurities from carbon monoxide and hydrocarbons decrease proportionally the air-fuel ratio and this decrease is finished near stoichiometry (14.7). As a second the amount of oxygen in the outlet gas starts at a slightly richer A / F (air-fuel) ratio than that Stoichiometry, to enlarge with an increase in the A / F ratio. Third, nitrogen oxides rise with the increase in the A / F ratio and reach the Peak near stoichiometry and then decrease as the A / F ratio increases.

Further experiments showed that the amount of nitrogen oxides in the outlet gas is proportional to the ratio of stroke to bore as shown in Figure 4- and that the outlet gas temperature shows a rising tendency with a delay in the ignition timing, as indicated in FIG. 5, whereupon

6Ü9613 / G664

2537078

- Ό · -

will be discussed in detail later. The outlet gas temperature In the experiment according to FIG. 5, moreover, in accordance with the measurement method 10, the "Japanese Exhaust Emission Test Procedure "measured.

The invention is based on the above experimental results. According to the invention, the carburetor is constructed in such a way that the air-fuel ratio in the air-fuel ratio is greater than the stoichiometry. The stroke-to-bore ratio of the machine is small. A heat barrier is provided which extends from the seat of the exhaust valve to the exhaust port. The outlet pipe system has the structure of a heat insulation. The ignition timing is timed so that the combustion gas temperature is below 2000 ⁰ C. With such a structure, the outlet gas temperature is above 750 G over a volume of the

Exhaust channel held, which follows the exhaust valve that corresponds to the machine displacement. In the invention the above-mentioned features are systematically combined in such a way that the gas temperature distribution from the cylinder to The exhaust valve will be most effective for reducing the impurities in the exhaust gas, as indicated by the exhausted Line in Fig. 5 is shown. The ratio of the area to the volume in the combustion chamber can be made large, to achieve a slower combustion rate, and the exhaust valve can be adjusted so that it is close opens the bottom dead center so that the combustion gas in the combustion chamber supports for a long time oxidation remains in the cylinder.

In Figs. 1 and 2, 1 and 2 each denote an air cleaner and a carburetor which is so improved over a known carburetor that a relatively lean one Air-fuel mixture (air-fuel ratio 15 to 20) is fed to the machine. 3 and. 4 · each denotes a Inlet tube and a combustion chamber that is flat with an area to volume (S / V) ratio of 4 cm. One

6U9813 / 0664

253707B

Outlet opening 6 is provided with an insert 13 which extends from the seat of the outlet valve to the entire inner surface the outlet opening extends as such. 8 denotes a Outlet pipe which connects to the outlet opening 6. The outlet pipe 8 is with heat-insulating maternal or covered another tube over the length 1 of the outlet tube, the thereby limited volume of the outlet line corresponds to the displacement volume of the machine. The tests carried out showed that that it is advantageous to choose such a design that the heat accumulation section in the outlet channel physically corresponds to the displacement volume of the machine. By a Such formation of the exhaust valve removes the heat from the exhaust gas passing through the length of the exhaust duct hold back. As shown in Fig. 6, these are the exhaust system provided with the above-mentioned insert and the heat accumulating means for a much higher temperature of the outlet gas at the two sections A and B shown in FIG is provided as compared to the temperature in the exhaust system without the liner and heat accumulator. In addition, according to the invention, the ignition timing is set so that it is somewhat retarded (10 ° to 20 ° of the crank angle) to the minimum advance for the best torque (MBT) is.

As described above, the air-fuel mixture supplied is a lean mixture with an air-to-fuel ratio (15 to 20) greater than the stoichiometric A / F ratio (14-, 7) «It follows that how from Fig. 3 it can be seen the impurities of carbon monoxide and hydrocarbons are reduced and that the oxidation in the exhaust gas continues as a relative large amount of oxygen is contained in the exhaust gas. For a further simplification of this procedure to reduce of the impurities, the ignition timing is retarded to the outlet gas temperature, such as the Examination of Fig. 6 shows to increase and become the

6 0 y 8 1 3/0 f-6 U

Muzzle insert 13 and the heat accumulation device used. As a result, the self-reaction of the impurities of carbon monoxide and hydrocarbons continues the oxidation proceeds weakly, resulting in a noticeable one Reduction of carbon monoxide and hydrocarbons leads. Incidentally, if the inlet pipe is heated and the pipe wall temperature is kept above 80G atomization of the mixture is carried out well. If the mixture is well distributed under the corresponding cylinder, the A / F ratio can be sufficiently large be. With reference to the shape of the combustion chamber, the S / V ratio is made large so that the engine has a flat-shaped space with a long flame path. Therefore, the end of the combustion attacks the Side of the expansion stroke over and in this way the combustion process proceeds in an almost slow and isothermal manner Combustion continues, thereby substantially reducing the amount of nitrogen oxides in the exhaust gas. One such low-speed combustion causes the temperature of the exhaust gas to rise, which leads to that the oxidation in the outlet opening and the outlet line is further supported. In addition, the Ignition timing delayed compared with that of a known engine and thus the maximum temperature of the combustion gas decreased. Together with the peculiar shape of the combustion chamber, this serves to further the To reduce the amount of nitrogen oxide in the outlet gas. This also facilitates the oxidation of carbon monoxide and Hydrocarbons.

As described above, the delay in the ignition timing causes an increase in the outlet temperature, as shown in Fig. 5, thereby creating a good state for oxidation after the gas is left out. The outlet opening 6 is completely covered with the insert 13, which is close to the seat of the outlet valve ends. The insert 13 serves to transfer the heat

609813/0664

253707B - 9 -

to prevent the cylinder head 14 and thus the drop in the exhaust temperature can be controlled to a minimum · The gas exhausted from the cylinder due to the opening of the exhaust valve becomes in the exhaust port oxidized very intensely and continuously oxidized in the outlet pipe, keeping it at a given temperature is maintained, thereby extremely reducing the impurities in the exhaust gas. This follows from the The fact that the deposit 1? above the inner wall of the outlet opening is provided and that the outlet valve is heat-insulated for a heat build-up, so that the outlet gas temperature can be kept in the temperature range that enables oxidation, i.e. above 75 ° C

The following table shows values of the internal combustion engine according to the invention in comparison with a known one Machine. Compare three toxic components in that Outlet gas and the temperatures at various locations in the outlet system. The measurements for this comparison were carried out according to Measurement Method 10 of the Japanese Exhaust Emission Test Procedure.

Outlet gas temperature Amount of outlet gas (measurement method 10)

Section Section _{c0 HC ΝΟχ} AB

Known 600 ° C 35O ° C 12 g / Km 2.2 g / Km 1.8 g / Km machine

800 ⁰ C 750 ⁰ C 1.8 g / Km 0.15 R / Km 0.9 g / Km machine according to the invention

'75 emissions funds funds funds

standard 2.10 0.25 1.20

(Measurement method 10).
(Japan)

Rating At the known reduction of about

Machine is the ^ _{0 /} ^ _{0 /} ^ _{0 /}

Heat spread great. ^ ' ^J ^'''

The invention complies with the '75 emissions

moderate machine has a noticeable condition
Heat build-up.

HU9813 / Q664

As can be seen from the table above, the three toxic components »nitrogen oxides, carbon monoxide and hydrocarbons substantially reduced and that The result of the reduction therefore meets the requirements of the strict Japanese 1975 emission standards.

The machine according to the invention with an additional known outlet gas recirculation device can to meet stricter emission requirements after 1975 will come into force.

As evidenced by Pig. '»■ results, the machine with the small ratio of stroke to bore is effective in reducing nitrogen oxides, since in this case the gap is large and the combustion of the gas in d ( ¹ Ui cylinder for a long time (see Fig. 4) persists.

In the event that the exhaust valve is set so that it opens at 50 ° before your bottom dead center to 20 ° afterwards (although in the case of the known valve this is opened at 47 ° to 60 ° before bottom dead center) and In addition, the ignition timing is delayed, that can Combustion gas at high temperature for a long time in the combustion chamber, with the result of facilitated oxidation stay.

A well-known air injection system for secondary air supply can partially be used in the machine according to the invention. The data obtained through many trials show that secondary air supply is not necessary for the reason that the A / F ratio is large when the car is running with a light load, i.e. driving on a level road at normal speed. If on the other hand the car falls with a heavy load (e.g. a road with a steep incline), the A / F ratio is that of the recorded Mixture low. In this way, the supply of secondary air is used to increase the A / F ratio in this case necessary.

6Ü9813 / 0664

To solve this problem, the gasoline-powered internal combustion engine is provided with an insert channel 11 for Secondary air is provided, which communicates with the outlet opening with the opening thereof near the outlet valve 5 and is also connected to an air cleaner 10. Kin test valve 9 is provided in the Kinlaßkanal 11 and is operated by the pulsation of the exhaust gases to open when the internal pressure of the exhaust port is lowered below atmospheric pressure, and to close when the former pressure is above the the latter pressure is raised. The negative pressure given by the pulsation leads to an introduction of Secondary air from the air cleaner 10 into the exhaust duct. In this case, the check valve 9 can be used in such a manner be that it is coupled to the accelerator pedal, and secondary air is immediately after or with a added certain time delay after pressing the pedal. The test valve 9 can also when it is opened can be controlled due to the change in negative pressure in the intake passage. When the vehicle is under heavy load is running, the temperature of the exhaust gas is high. In such a case, the supply of secondary air can be on the Controlled based on the change in outlet gas temperature.

Claims (12)

2537078 claims 1. Gasoline powered internal combustion engine, characterized by an adjustment of the ignition timing and by a heat accumulation device which extends from the seat of the exhaust valve to an opening of an exhaust port including an exhaust port in order to thermally isolate the exhaust port, whereby the combustion gas temperature is below 2000 ⁰ C during the combustion process is held, and the outlet gas temperature is maintained above 75O ⁰ G in the outlet channel, which adjoins the outlet valve, which has a volume corresponding to the volume of the cylinder of the machine. 2. Internal combustion engine according to claim 1, characterized by a carburetor for generating an air-fuel ratio of the mixture is greater than the stoichiometric ratio. 3. Internal combustion engine according to claim 1, characterized by means for supplying secondary air in the area near the outlet opening around the air-fuel -To make ratio of the absorbed mixture greater than the stoichiometric ratio, if whose air-fuel ratio is less than the stoichiometric ratio. 4. Internal combustion engine according to claim Λ , characterized by a stroke to bore ratio of less than 0.9 5. Internal combustion engine according to claim 1, characterized in that the exhaust valve is within the range from 50 ° before bottom dead center to 20 ° after bottom Dead center is open. 6Ü9813 / 0664 6. Internal combustion engine according to claim 2, characterized by means for supplying secondary air in the area near the outlet opening to the air-fuel ? -To make the ratio of the intake mixture greater than the stoichiometric ratio when the air-fuel ratio is less than the stoichiometric ratio. 7. Internal combustion engine according to claim 2, characterized by a stroke to bore ratio of less than 0.9 8. Internal combustion engine according to claim 2, characterized in that the exhaust valve is within the area from 50 ° before bottom dead center to 20 ° after bottom Dead center is open. 9. Internal combustion engine according to claim 3 »characterized with a stroke to bore ratio of less than 0.9. 10. Internal combustion engine according to claim 3 »thereby characterized in that the exhaust valve is within the range from 50 ° before bottom dead center to 20 after bottom Dead center is open. 11. Internal combustion engine according to claim 4, characterized in that the exhaust valve is within the range from 50 ° before bottom dead center to 20 ° after bottom Dead center is open. 12. Internal combustion engine according to claim 6, characterized by a stroke to bore ratio of less than 0.9 and characterized in that the exhaust valve is within the range of 50 ° before bottom dead center to 20 ° after is open to the bottom dead center. 6U98 13/0664