JP2016205280A - Engine start system - Google Patents

Abstract

An engine start system including an ISG and a starter that can improve fuel consumption as compared with the prior art. When a start request is issued when the diesel engine 4 is cold, an ECU 13 operates a starter 5 to start rotation of a crankshaft 1, and a measured value R of a rotation sensor 12 at the start rotation is preliminarily determined. If the measured value R is less than the threshold value X, the starter 5 continues to start crankshaft rotation without starting the ISG 7 when the threshold value X is greater than or equal to the set threshold value X. To start and rotate the crankshaft 1 in cooperation with the starter 5. [Selection] Figure 1

Description

  The present invention relates to an engine start system, and more particularly, to an engine start system including an ISG and a starter that can improve fuel efficiency as compared with the prior art.

  In recent years, ISG (Integrated Starter Generator) in which a starter and a generator are integrated has attracted attention (for example, see Patent Document 1). By using the ISG to generate power during deceleration, perform idling stop, assist during acceleration, and the like, the fuel efficiency of the vehicle can be improved.

  This ISG is usually connected to the crankshaft of the engine via an auxiliary belt, but it is difficult to transmit large rotational power to the crankshaft because it may slip due to high friction. Therefore, ISG is mainly used for restarting from an idling stop. On the other hand, a conventional starter is used for starting from the cold time (first start of the day). In starting from this cold time, starting at a low temperature (for example, −25 ° C.) must be taken into consideration, so the starter starter motor has a large output.

  For example, in the case of a 3.0 L diesel engine start system, the output of the start motor is 4 kW while the output of the ISG is 2 kW.

  As described above, in the current vehicle, although a large starter has to be equipped even though the ISG is equipped, there is a problem that the effect of improving the fuel consumption is hindered.

Japanese Patent No. 3090312

  The objective of this invention is providing the engine starting system provided with ISG and a starter which can improve a fuel consumption conventionally.

  An engine start system according to the present invention that achieves the above-mentioned object is an engine comprising a starter for starting and rotating an engine crankshaft, an ISG connected to the crankshaft via an endless belt member, and a control means. In the start system, when a start request is issued when the engine is cold, the control means operates the starter to start the crankshaft, and the engine speed at the start rotation is preset. When the engine speed is less than the threshold, the starter rotation of the crankshaft by the starter is continued without starting the ISG when the engine speed is less than the threshold. To start and rotate the crankshaft in cooperation with the starter. It is intended.

  According to the engine start system of the present invention, when it is difficult to start a diesel engine, the starter can be reduced in size and weight because the ISG is started and the engine is started in cooperation with the starter. The fuel consumption can be improved compared to the conventional case.

It is a block diagram of the engine starting system which consists of embodiment of this invention. It is a flowchart explaining the function of ECU.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an engine start system according to an embodiment of the present invention.

  This engine starting system is connected to a starter 5 for starting a diesel engine 4 through a ring gear 3 connected via a flywheel 2 around the crankshaft 1 and an endless accessory belt 6 to the crankshaft 1. ISG7.

  The starter 5 mainly includes a pinion 8 that can mesh with the ring gear 3 and a starter motor 9 that rotationally drives the pinion 8. The starter motor 9 uses a lead battery 10 as a power source, and its rotating shaft 11 can be expanded and contracted toward the ring gear 3 by an actuator (not shown).

  The ISG 7 supplies power to the electrical components and charges the lead battery 10 as a generator (alternator) when the vehicle is running or stopped, and functions as a starter when restarting from an idling stop.

  The crankshaft 1 is provided with a rotation sensor 12 that measures the engine speed of the diesel engine 4.

  The starter 5, the ISG 7 and the rotation sensor 12 are connected to an ECU 13 as control means through a signal line (indicated by a one-dot chain line).

  The function of the ECU 13 in such an engine start system will be described below with reference to FIG.

  The ECU 13 confirms whether or not there is a start request when the diesel engine 4 is cold (S10). When the start request is issued, the starter 5 starts and rotates the crankshaft 1 (S20) and the measured value of the rotation sensor 12 is measured. R is input (S30) and compared with a preset threshold value X (S40). The threshold value R is preferably a rotational speed in the range of 50 to 200 rpm. In the case of a 1.0 to 3.0 L diesel engine, the threshold value R is preferably 100 rpm. When the engine speed is 100 rpm, the temperature at the time of compression in the cylinder becomes 300 ° C. even at low temperatures, and sufficiently exceeds 250 ° C., which is the temperature at which light oil self-ignites.

  If the measured value R is greater than or equal to the threshold value X, the starting rotation of the crankshaft 1 by only the starter 5 is continued without starting the ISG 7 (S50). This starting rotation of the crankshaft 1 continues until the measured value R reaches the idle speed Y (S60).

  On the other hand, when the measured value R is less than the threshold value X, the ISG 7 is started (S70), and the crankshaft 1 is started and rotated in cooperation with the starter 5 (S80). This starting rotation of the crankshaft 1 continues until the measured value R reaches the idle speed Y (S90).

  As described above, when it is difficult to start the diesel engine 4 due to a low temperature or the like, the starter 5 is started in cooperation with the starter 5 by starting the ISG 7, so the starter 5 is reduced in size and weight. Therefore, the fuel consumption can be improved as compared with the prior art.

  For example, when the present invention is applied to a starting system of a 3.0-liter diesel engine 4 whose output of ISG 7 is 2 kW, the output of the starting motor 9 can be reduced from 4 kW to 2 kW, so that the starter 5 can be reduced in size and weight. Is possible.

1 Crankshaft 4 Diesel Engine 5 Starter 6 Auxiliary Belt 7 ISG
9 Start motor 12 Rotation sensor 13 ECU

Claims (2)

In an engine starting system comprising a starter for starting and rotating an engine crankshaft, an ISG connected to the crankshaft through an endless belt member, and a control means,
When a start request is issued when the engine is cold, the control means operates the starter to start and rotate the crankshaft,
If the engine speed at the start rotation is greater than or equal to a preset threshold, the starter continues the start rotation of the crankshaft without starting the ISG,
When the engine speed is less than the threshold value, the ISG is activated to start and rotate the crankshaft in cooperation with the starter.   The engine start system according to claim 1, wherein the threshold value is a rotation speed in a range of 50 to 200 rpm.

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