JP2002061542A - Fuel injection device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a proper injection quantity in a fuel injection device for an automobile using liquefied dimethyl ether as fuel. SOLUTION: A temperature regulator 60 is provided in a fuel force-feeding passage 20 in the fuel injection device M for an automobile using liquefied dimethyl ether as fuel, and a temperature sensor 80 (a temperature detecting means) is provided on a common rail. Based on detected temperature by the sensor 80, the temperature regulator 60 is regulated by a control unit 70 to keep fuel temperature constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device for an automobile using dimethyl ether as a fuel.

[0002]

2. Description of the Related Art In recent years, dimethyl ether pressurized and liquefied has attracted attention as a fuel for diesel vehicles replacing diesel oil and the like. According to this liquefied dimethyl ether fuel, soot and NOx emissions can be reduced.

[0003]

Generally, the density of a liquid decreases as the temperature increases, and the density increases as the temperature decreases. However, the liquefied dimethyl ether has a particularly large change in density due to this temperature. For this reason, there has been a problem that the injection amount becomes insufficient or excessive due to the temperature fluctuation.

[0004]

Means for Solving the Problems The present invention has been made to solve the above problems, and the first feature of the present invention is as follows.
Injection nozzle facing the combustion chamber, supply means for supplying liquefied dimethyl ether as fuel to the injection nozzle, temperature detection means for detecting the temperature of the fuel in the supply means, and a constant fuel temperature based on the detected temperature And a temperature adjusting means for adjusting the temperature of the vehicle.

[0005] A second feature of the present invention is that an injection nozzle facing the combustion chamber, supply means for supplying liquefied dimethyl ether as fuel to the injection nozzle, and temperature detection means for detecting the temperature of the fuel in the supply means. And a control means for controlling the opening and closing operation of the injection nozzle so that the injection amount becomes desired based on the detected temperature. Here, it is preferable that the apparatus further comprises a pressure detecting means for detecting a pressure of the fuel in the supply means, and the control means performs the control based on the detected pressure and the detected temperature. Preferably, the supply means has a common rail for storing the fuel at a high pressure, and the common rail is provided with the temperature detection means and the pressure detection means.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a vehicle fuel injection device M according to a first embodiment of the present invention. The injection device M includes a fuel tank 10, a fuel pressure feed line 20 extending from the tank 10, a fuel pump 30 provided in the pressure feed line 20, and a pressure feed line 2 downstream of the pump 30.
And a common rail 40 connected to zero. Tank 1
At 0, dimethyl ether liquefied under pressure is stored as fuel. This fuel is pumped by the pump 30 and stored in the common rail 40 at high pressure. A plurality of injection nozzles 50 are connected to the common rail 40 via the distribution path 21. These injection nozzles 50 face a combustion chamber (not shown) of the engine and inject fuel. Tank 10, pressure feed path 20, pump 30,
The common rail 40 and the distribution path 21 constitute "supply means" in the claims. Note that reference numeral 2
Reference numeral 2 denotes a fuel return path 22 that returns a part of the fuel from the leak outlet of the injection nozzle 50 to the pressure feed path 20 upstream of the pump 30.

[0007] The features of the present invention will be described. Pumping path 20
Is provided with a temperature controller 60. This temperature controller 60 has a cooling unit 61 and a heating unit 62. The cooling unit 61 cools liquefied dimethyl ether fuel by introducing cold heat from, for example, an air conditioner of an automobile and applying the cold heat to the pressure feed path 20. The heating unit 62 is configured by, for example, an electric heater or a hot water channel taken from engine cooling water, and heats the fuel.

Further, the fuel injection device M includes a control unit 70 and a temperature sensor 80 (temperature detecting means) provided on the common rail 40. The temperature sensor 80 detects the temperature of the fuel in the common rail 40. The control unit 70 receives a detection signal from the temperature sensor 80 and outputs a control signal to the temperature controller 60. In the control unit 70, a suitable temperature of the fuel is set in advance, for example, in a range from normal temperature to about 50 ° C. The control unit 70 and the temperature controller 60 constitute "temperature control means" in the claims.

The control operation of the control unit 70 in the vehicle fuel injection device M configured as described above will be described. The control unit 70 includes the temperature sensor 8
The detected fuel temperature according to 0 is compared with the set temperature.
When the detected temperature is higher than the set temperature, the cooling unit 61 of the temperature controller 60 is operated. When the detected temperature is lower than the set temperature, the heating unit 62 is operated. This allows the fuel to be maintained at the set temperature. Therefore,
The density of the fuel can be kept constant. As a result, it is possible to prevent the injection amount from becoming insufficient or excessive, and to always secure a desired injection amount.

Next, a second embodiment of the present invention will be described.
In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted. The vehicle fuel injection device M ′ according to this embodiment includes:
The temperature controller 60 is not provided. The common rail 40 has a pressure sensor 81 in addition to the temperature sensor 80.
(Pressure detecting means) is provided. The control unit 71 of the device M ′ receives the detection signals of these sensors 80 and 81 and controls the opening / closing operation of the injection nozzle 50 based on the signals.

That is, the control unit 71
The injection nozzle 50 outputs a pulse signal having a width corresponding to the engine output.
Output to the solenoid of the injection nozzle 50
Is lifted (opened). When the temperature detected by the temperature sensor 80 rises (the fuel density decreases), the pulse width is increased. Also, when the pressure detected by the pressure sensor 81 decreases (fuel density decreases), the pulse width is similarly increased. As a result, the valve opening time, that is, the injection period is extended, and a desired injection amount can be secured irrespective of the decrease in the fuel density. Conversely, when the detected pressure increases (fuel density increases), the pulse width is shortened. As a result, the injection period is shortened, and a desired injection amount can be ensured regardless of the increase in density.

[0012] In addition to or instead of changing the pulse width, the output timing of the pulse, that is, the injection timing may be advanced or delayed. Specific values of the pulse width and the timing are determined based on, for example, a map showing the relationship between the pulse width and the fuel temperature and the pressure in advance.

The present invention is not limited to the above embodiment, but can adopt various forms. For example, the temperature sensor 80
In addition to the common rail 40, the fuel tank 10 and the distribution path 21
Etc., it can be arranged at any place of the supply means. The same applies to the pressure sensor 81. The injection device according to the first aspect of the present invention is applied not only to an electronic control type but also to a jerk type, for example. The injection device according to the second aspect of the present invention is applied not only to the device using the common rail 40 but also to another electronic control type injection device using a unit injector, an electronic control pump, or the like.

[0014]

As described above, according to the first aspect of the present invention, it is possible to suppress the temperature fluctuation of the fuel and thereby to secure an appropriate injection amount. According to the second aspect of the present invention, by controlling the opening / closing operation of the injection nozzle, it is possible to secure an appropriate injection amount regardless of fuel temperature fluctuation. In addition, by performing the control in response to the fuel pressure fluctuation, an appropriate injection amount can be more reliably secured. Further, by providing the temperature and pressure detecting means on the common rail, the reliability of the detected value can be increased, and an appropriate injection amount can be more reliably secured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 M, M 'Automotive fuel injection device 10 Fuel tank 20 Fuel pressure feed path 30 Fuel pump 40 Common rail 50 Injection nozzle 60 Temperature controller 70, 71 Control unit 80 Temperature sensor (temperature detection means) 81 Pressure sensor (pressure detection means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 31/20 F02M 31/20 K 37/00 P 37/00 341C 341 47/00 E 47/00 47 / 02 47/02 53/00 N 53/00 55/02 350E 55/02 350 31/12 321D (72) Inventor Yuji Furuya 3-26, Yaumicho, Higashimatsuyama City, Saitama Prefecture Bosch Automotive System Higashimatsuyama Plant (72) Inventor Yukio Hirai 39, Higashihara, Chiyo-ji, Odai-gun, Osato-gun, Saitama Prefecture Inside of Xexel Valeo Climate Control Co., Ltd. Bosch Automotive System H-Matsuyama Plant F-term (reference) 3G066 AA07 AB04 AC09 BA51 CC06U CD22 CD23 CE22 DA01 DC15 DC18 3G084 AA05 BA13 DA04 EB11 FA00 3G301 HA04 HA23 MA01 PB01Z PB08Z

Claims (4)

[Claims] 1. An injection nozzle facing a combustion chamber, supply means for supplying liquefied dimethyl ether as fuel to the injection nozzle, temperature detection means for detecting the temperature of the fuel in the supply means, and based on the detected temperature. A fuel injection device for an automobile, comprising: temperature adjustment means for adjusting the fuel temperature to be constant. 2. An injection nozzle facing the combustion chamber, supply means for supplying liquefied dimethyl ether as fuel to the injection nozzle, temperature detection means for detecting the temperature of the fuel in the supply means, and based on the detected temperature. Control means for controlling the opening / closing operation of the injection nozzle so that the injection amount becomes desired. 3. The apparatus according to claim 2, further comprising a pressure detecting means for detecting a pressure of the fuel in the supply means, wherein the control means performs the control based on the detected pressure and the detected temperature. 3. The vehicle fuel injection device according to 2. 4. The vehicle according to claim 3, wherein the supply means has a common rail for storing the fuel at a high pressure, and the temperature detection means and the pressure detection means are provided on the common rail. Fuel injection device.