JP2005113756A - Fuel injection controller of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a reduction in overall system costs by making a sensor for detecting an engine temperature inexpensive and besides eliminating interconnections from the sensor to a control unit in a fuel injection controller of an engine. <P>SOLUTION: A control unit 5 and a throttle chamber 3 that is a peripheral equipment of the engine 1 are integrated with each other. Besides, a temperature sensor 6 for detecting the engine temperature is directly mounted on a board 5b of the control unit 5. Using correlative data preliminary inspected under the same condition with regard to a correlation between an engine peripheral temperature detected by the temperature sensor 6 and an actual engine temperature, the actual engine temperature is estimated from an engine peripheral temperature detected by the temperature sensor 6. Thereby, a fuel increment required from low-temperature start to completion of warm up and hours required for the increment are calculated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection control device that is disposed in a fuel supply system for a spark ignition engine and electronically controls a fuel injection amount based on an engine temperature.

  In a fuel ignition system for a spark ignition engine, in order to ensure a stable rotation from the cold start of the engine to the completion of warm-up, it is common to correct the fuel injection amount in accordance with the engine temperature. . That is, for example, in the fuel injection control apparatus described in Japanese Patent Laid-Open Nos. 5-1588 and 6-117316 and shown in FIG. 3, a water temperature sensor 11 and an oil temperature sensor 12 attached to the engine 1 are used. The control unit 20 judges the warming-up progress state of the engine 1 based on the engine temperature detected by the above, and adjusts the fuel injection amount of the fuel injection valve 21 to be increased from the warm time.

However, since the water temperature sensor 11 and the oil temperature sensor 12 are directly attached to the engine 1, protection means such as waterproofing is required, and since the control unit 20 is usually disposed at a position away from the engine 1, the water temperature sensor 11. In addition, wiring for connecting to the oil temperature sensor 12 is required, and an output unit for outputting a signal in the sensor is required. Therefore, the sensor itself is expensive and the overall system cost tends to be expensive.
JP-A-5-1588 JP-A-6-117316

  The present invention is intended to solve the above-described problems, and in a fuel injection control device for an engine, a sensor for detecting engine temperature is made inexpensive and wiring to a control unit is not required. It is an object to be able to keep costs low.

  Therefore, the present invention provides a fuel injection control device that is arranged in a fuel supply system of an engine and electronically controls the fuel injection amount based on the engine temperature. The control unit is integrated with engine peripheral devices and detects the engine temperature. A temperature sensor was directly attached to the control unit board to detect the engine ambient temperature.

  As a result, the temperature sensor for detecting the engine temperature is built into the control unit board, so that the output unit is unnecessary and protection means such as waterproofing is not required, and the wiring is connected to the control unit. Is not necessary, and the entire apparatus is inexpensive. Further, since the engine peripheral device and the control unit are integrated, the number of parts is reduced, so that the whole system is compact and easy to assemble, and the system cost can be kept low.

  In addition, since the temperature sensor detects the temperature of peripheral devices that are affected by the engine's heat, data indicating the correlation between the engine ambient temperature detected by the temperature sensor and the actual engine temperature is recorded in the storage means of the control unit. The actual temperature of the engine is estimated based on the temperature detected by the temperature sensor, and the fuel increase amount and the increase amount required based on the engine ambient temperature detected by the temperature sensor when the engine is started. If the time is determined, the fuel injection amount increase correction can be made more accurate.

  Furthermore, for this fuel addition and / or its increase time, the engine warm-up condition is estimated by continuous or intermittent temperature monitoring using a temperature sensor, or the total number of engine revolutions after the engine is started continuously. If the engine warm-up condition is estimated by calculating automatically or intermittently, and if necessary, corrections are made as necessary, it will be possible to make more precise corrections to increase in response to the warm-up progress. Become.

  Furthermore, if the temperature sensor is a semiconductor sensor, it is compact and easy to attach to the substrate. In addition, if the engine peripheral device into which the control unit is integrated is a throttle chamber arranged at a location close to the engine, the engine temperature can be indirectly detected more accurately from the temperature inside the housing of the control unit. This also makes it possible for the throttle opening sensor and the intake air amount sensor to be close to or integrated with the control unit, so that the wiring connecting them can be shortened or unnecessary, further reducing the system cost. It becomes possible to suppress.

  According to the present invention, the sensor for detecting the engine temperature is inexpensive and the wiring to the control unit is not required, so that the overall system cost can be kept low.

  An embodiment of the present invention will be described with reference to the drawings. In the fuel injection control device of the present embodiment shown in FIG. 1, a control unit 5 is integrated with a throttle chamber 3 connected to an intake pipe 2 of an engine 1. The temperature sensor 6 which is a semiconductor diode sensor is directly attached on the substrate 5b. Specifically, the temperature sensor 6 is directly attached on the substrate 5b and is built in the housing 5a of the control unit 5. Therefore, the engine temperature is indirectly detected inside the housing 5a.

  As described above, according to the present embodiment in which the temperature sensor 6 is directly mounted on the substrate 5b, wiring and an output unit for sending an output signal to the control unit 5 are not required, and the temperature sensor 6 is built in the housing 5a. According to this embodiment, protection means such as waterproofing is not required.

  On the other hand, since the temperature sensor 6 does not detect the temperature of the cooling water or engine oil of the engine 1, the temperature detected by this is not the actual engine temperature. That is, the temperature in the housing 5a is lower than the actual temperature of the engine 1, and a slight delay occurs with respect to the temperature change of the engine 1.

  Therefore, as a method of accurately detecting the actual engine temperature, the correlation between the engine ambient temperature detected in the housing 5a in advance under the same conditions and the actual engine temperature at that time is examined and converted into data as a predetermined function. This is stored in the ROM of the control unit 5, and the actual engine temperature is estimated from the engine ambient temperature detected by the temperature sensor 6 using this correlation data.

  Based on the engine ambient temperature detected at the time of starting the engine, the control unit 5 keeps the engine running from the start to the completion of warm-up, so that the required fuel increase amount in addition to the normal fuel injection amount And the amount of increase time are calculated, and based on this, a command is issued to the fuel injection valve 4. Since the housing 5a of the control unit 5 is integrated with the throttle chamber 3, it is easy to dispose the throttle opening sensor and the inflow air amount sensor in the housing 5a or at a close distance.

  Further, the control unit 5 continuously monitors the engine ambient temperature by using the temperature sensor 6 to constantly estimate the warm-up state of the engine 1, and corrects the fuel increase amount and the increase time corresponding to the change in the engine temperature. Is applied as necessary. The engine ambient temperature may be monitored intermittently, not continuously.

  Next, the operation of the fuel injection control device in the present embodiment will be described using the flowchart shown in FIG. First, the control unit 5 detects the temperature in the housing 5a at the time of starting with the temperature sensor 6 by starting the engine, and based on this temperature, the engine periphery and the actual engine that are the temperatures in the housing 5a recorded in the ROM. The actual engine temperature is estimated using data showing the correlation with temperature (A1).

  Then, based on the estimated actual engine temperature, it is determined whether or not it is a temperature at which the basic fuel injection amount needs to be increased and corrected during the period from the start to the completion of warm-up (A2). When it is determined that the engine temperature is sufficiently high and there is no need to correct the increase, that is, when it is determined to be a warm start, the increase command is not issued (C1) and the normal operation is performed.

  On the other hand, if it is determined that an increase is required, that is, it is a cold start, the control unit 5 calculates a fuel increase amount and an increase time required to keep the engine running well until the warm-up is completed ( A3) An increase command based on the calculated value is issued (A4), and the fuel increase correction is performed for the determined time.

  The increase / increase time is calculated by estimating the engine temperature that gradually increases from the start by a preset calculation method, but it may differ greatly from the actual engine temperature due to various conditions. There is a possibility that the engine operation until the warm-up is completed cannot be maintained well. Therefore, the engine ambient temperature is continuously monitored for a while after the engine is started (A5).

  In this monitoring, it is continuously determined whether or not the predicted value of the engine temperature that gradually increases corresponding to the elapsed time differs from the actual engine temperature. If there is no difference, the initially determined fuel increase amount and increase amount are determined. When the determined increase time ends (B1), the increase command is stopped (B2). Needless to say, there is a certain allowable range in determining whether the predicted value differs from the actual engine temperature.

  On the other hand, if the actual engine temperature is different from the predicted value of the engine temperature, a correction increase amount and a correction increase time for ensuring good engine operation are calculated (A7). For example, if the estimated engine temperature at the detected engine ambient temperature is lower than the predicted engine temperature, the increase amount and / or the increase time is increased, and if it is higher, the increase is decreased (the increase stop is sometimes stopped). The command is changed to (A8). When the increase time ends (A9), the increase command is stopped (A10).

  In addition, regarding the correction of the fuel increase amount and the increase time, instead of means for continuously monitoring the engine ambient temperature, the engine speed is continuously or intermittently monitored to calculate the total speed from the start. A means for calculating the correction amount by estimating the actual engine temperature may be used. Further, the engine peripheral device in which the control unit 5 is integrated and arranged may be a device other than the throttle chamber 3 as long as it can faithfully reflect the engine temperature.

  As described above, in the fuel injection control device according to the present embodiment, the control unit 5 is integrated with the throttle chamber 3 which is an engine peripheral device, and the temperature sensor 6 is disposed inside the housing 5a to indirectly control the engine temperature. Detectable. This eliminates the need for a protective means such as waterproofing for the temperature sensor 6 and eliminates the need for a signal output unit, so that the temperature sensor can be made inexpensive and no connection wiring to the control unit 5 is required. As a result, the entire device becomes inexpensive. Further, since the housing 5a is integrated with the throttle chamber 3 and the number of parts is reduced as a whole fuel supply system, the assembly can be easily performed and the system cost can be reduced.

Schematic which shows embodiment of this invention. The flowchart which shows operation | movement of the fuel-injection control apparatus of FIG. Schematic which shows a prior art example.

Explanation of symbols

1 Engine, 3 Throttle chamber, 4 Fuel injection valve, 5 Control unit, 5a Housing, 5b Substrate, 6 Temperature sensor

Claims (6)

In a fuel injection control device that is arranged in an engine fuel supply system and electronically controls a fuel injection amount based on an engine temperature,
A control unit is integrated with peripheral devices of the engine, and a temperature sensor that detects the engine temperature is directly attached to a substrate of the control unit, and detects the engine ambient temperature.
A fuel injection control device.   In the control unit, data indicating the correlation between the engine ambient temperature detected by the temperature sensor and the actual engine temperature is recorded in the storage unit, and the control unit uses the data from the engine ambient temperature detected by the temperature sensor. The actual temperature of the engine is estimated, and the required fuel increase amount and the increase time are determined based on the engine ambient temperature detected by the temperature sensor when the engine is started. Fuel injection control device.   The fuel increase amount and / or the time for increasing the fuel amount is estimated by estimating the warm-up state of the engine by continuous or intermittent temperature monitoring using the temperature sensor, and making corrections as necessary. Item 3. The fuel injection control device according to Item 2.   The fuel increase amount and / or the time for increasing the fuel amount is estimated by estimating the warm-up state of the engine by continuously or intermittently calculating the sum of the engine speeds after the engine is started, and making corrections as necessary. The fuel injection control device according to claim 2, wherein the fuel injection control device is used.   The fuel injection control device according to claim 1, 2, 3, or 4, wherein the temperature sensor is a semiconductor sensor. 6. The fuel injection control device according to claim 1, wherein the peripheral device is a throttle chamber.

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