JPS6311308Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electronically controlled fuel injection device for an internal combustion engine.

As is well known, control of the injection amount in an electronically controlled fuel injection device for an automobile engine, etc., involves adding various correction amounts to the basic injection amount based on the operating conditions of the engine, such as rotational speed correction, air temperature correction, acceleration amount increase, etc. The optimal fuel injection amount is sequentially determined by adding a warm-up amount increase, etc. The warm-up increase described above is to automatically adjust the corrective injection amount according to the cooling water temperature after the engine starts, and to complete warm-up quickly and smoothly. As shown, in a cooling water passage 2 in which a thermostat 1 is interposed for selectively switching the cooling water flow passage between a radiator (not shown) and a bypass passage that bypasses the radiator, the thermostat 1
A water temperature sensor 3 is disposed closer to the engine, and a control unit 4 calculates a fuel increase coefficient to be added to the basic injection amount according to the output of the water temperature sensor 3, and controls the opening of the fuel injection valve 5 based on this. The valve time is controlled to be extended as appropriate. FIG. 2 shows the relationship between the above-mentioned increase coefficient and cooling water temperature. As is clear from the figure, the lower the cooling water temperature, the greater the increase in injection amount, and the lower the cooling water temperature, the greater the injection amount.
The increase in volume ends when the temperature (°C) is reached.

However, with conventional systems that are configured to warm up and increase the amount based solely on the cooling water temperature, there is no problem when the engine is idled sufficiently after starting and is allowed to slowly slow down. However, if the coolant temperature rises relatively rapidly, such as when the engine shifts to normal running immediately after starting without idling, the engine may not warm up sufficiently even if the coolant temperature reaches the specified temperature. As a result, drivability deteriorates for a while after the warm-up increase described above is completed.

As an example, Fig. 3 shows the cooling water temperature b and fuel injection increase coefficient c when the engine is started from room temperature and run in mode 11 immediately after starting as shown in a. As is clear, the cooling water temperature rises relatively rapidly after startup, and the increase coefficient gradually decreases as the cooling water temperature rises until the cooling water temperature reaches the set temperature (70℃). 0
becomes. On the other hand, the above-mentioned thermostat 1, which controls the flow of water to the radiator, is set to open at 80 to 90 degrees Celsius, so when the coolant reaches this temperature, it starts flowing the coolant in the engine to the radiator. Dissipate heat. The coolant temperature will eventually be maintained around this temperature, but if the coolant temperature rises rapidly like this, there is a large relative temperature difference with the radiator, etc., so if thermostat 1 opens, The temperature of the cooling water temporarily decreases and the thermostat 1 closes, and then the temperature of the cooling water rises again and the thermostat 1 opens, causing large fluctuations in the temperature of the cooling water. While this temperature fluctuation is large, the intake manifold riser section is generally not sufficiently warmed up, so it is an operating region where fuel atomization and distribution are not yet sufficient. Since it ends when the temperature reaches 70°C, during this period the emission becomes a region where drivability deteriorates accompanied by deterioration of fuel efficiency. Further, after a certain period of time has passed and the cooling water temperature has stabilized, the thermostat 1 is almost always open, and at this point, the engine is generally fully warmed up, including the intake manifold and other parts.

This idea was created in view of the conventional problems mentioned above.
We focused on the characteristic that even when the engine is run immediately after a cold start, the lubricating oil temperature of the engine rises more slowly than the coolant temperature, and when it is fully warmed up, it becomes higher than the coolant temperature. When comparing both temperatures, when the lubricating oil temperature is low, increasing the amount of fuel even if the cooling water temperature is higher than the predetermined temperature will prevent the above-mentioned temporary deterioration of drivability. , the purpose is to prevent deterioration of emissions.

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

FIG. 4 schematically shows the configuration of the electronically controlled fuel injection device according to this invention, in which a water temperature sensor 3 is located closer to the engine 6 than the thermostat 1 in the cooling water passage 2.
An oil temperature sensor 8 for detecting the lubricating oil temperature is also provided in the oil pan 7. The control unit 4 controls the valve opening time, that is, the injection amount, of the fuel injection valve 5 based on the output signals of these sensors 3 and 8. is below a predetermined temperature, a fuel increase coefficient is calculated and set sequentially according to the cooling water temperature, the fuel amount is increased based on this, and the lubricating oil temperature detected by the oil temperature sensor 8 and the cooling water temperature are In comparison, when the lubricating oil temperature is relatively low, the amount of fuel is increased based on a predetermined increase coefficient even if the cooling water temperature is higher than a predetermined temperature.

Figure 5 shows the cooling water and lubricating oil temperatures b, when the engine is started from room temperature and run in mode 11 immediately after starting as in Figure 3, as in Figure 3;
The fuel injection increase coefficient c and the HC emission amount d are shown, and in particular, c and d are shown in comparison with the conventional one. That is, as is clear from Figure b, the lubricating oil temperature rises more slowly than the cooling water temperature, and the cooling water temperature remains constant until the cooling water temperature stabilizes around the operating temperature of the thermostat 1. Although it is relatively lower, once the temperature of this lubricating oil has risen sufficiently, it has the characteristic of becoming higher than the coolant temperature, and especially when the lubricating oil temperature exceeds the coolant temperature, the engine will almost completely warm up. It is in the machine state. Therefore, the period from when the cooling water temperature reaches a predetermined temperature until the time when the cooling water temperature and the lubricating oil temperature match almost corresponds to the above-mentioned drivability deterioration region,
During this time, by maintaining an appropriate fuel increase coefficient as shown in c in the figure, it is possible to eliminate deterioration in drivability caused by deterioration in fuel atomization and distribution.
As shown in the figure, emission is also greatly improved.

As is clear from the above explanation, with the electronically controlled fuel injection system according to this invention, even when the vehicle is started immediately after a cold start, the drivability and emissions deteriorate temporarily as in the case of the conventional system. This ensures smooth drivability until the engine is completely warmed up.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the configuration of a conventional electronically controlled fuel injection system, Figure 2 is a graph showing the relationship between increase coefficient and cooling water temperature, Figure 3 is a conventional characteristic diagram when running in 11 modes, FIG. 4 is an explanatory diagram of the configuration of the electronically controlled fuel injection system according to the present invention, and FIG. 5 is a characteristic diagram of the present invention when running in the 11 mode. 1...Thermostat, 3...Water temperature sensor, 4
...Control unit, 5...Fuel injection valve,
8...Oil temperature sensor.

Claims (1)

[Scope of utility model registration request] The engine is equipped with a water temperature sensor that detects the engine cooling water temperature, an oil temperature sensor that detects the lubricating oil temperature, and a control unit that corrects and controls the amount of fuel injected during warm-up based on the output signals of these sensors. When the temperature is cold below a predetermined temperature, the amount of injected fuel is increased based on the increase coefficient set according to the cooling water temperature, and when the lubricating oil temperature is low by comparing the cooling water temperature and the lubricating oil temperature, 1. An electronically controlled fuel injection device for an internal combustion engine, characterized in that it is configured to increase the amount of injected fuel based on a predetermined increase coefficient even when the cooling water temperature is higher than a predetermined temperature.