JP3074830B2 - Fuel injection device for internal combustion engine - Google Patents
Fuel injection device for internal combustion engineInfo
- Publication number
- JP3074830B2 JP3074830B2 JP03227189A JP22718991A JP3074830B2 JP 3074830 B2 JP3074830 B2 JP 3074830B2 JP 03227189 A JP03227189 A JP 03227189A JP 22718991 A JP22718991 A JP 22718991A JP 3074830 B2 JP3074830 B2 JP 3074830B2
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- pressure
- pressure pump
- valve
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
- F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
- F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
Description
【０００１】[0001]
【産業上の利用分野】本発明は内燃機関の燃料噴射装置
に関するBACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for an internal combustion engine.
【０００２】[0002]
【従来の技術】低圧ポンプから吐出された燃料を高圧ポ
ンプに供給し、高圧ポンプから吐出された燃料を燃料噴
射弁に供給し、高圧ポンプから吐出された燃料の圧力を
計測してこの圧力が目標燃料圧となるように高圧ポンプ
から吐出される燃料量を制御するようにした内燃機関が
公知である（特開昭６３−１１７１５０号公報参照）。
この内燃機関では高圧ポンプから吐出された燃料の圧力
が目標燃料圧よりも高くなったときには高圧ポンプの吐
出量を減少させ、高圧ポンプから吐出された燃料の圧力
が目標燃料圧よりも低くなったときには高圧ポンプの吐
出量を増大させ、それによって高圧ポンプから吐出され
た燃料の圧力を目標燃料圧に維持するようにしている。2. Description of the Related Art Fuel discharged from a low pressure pump is supplied to a high pressure pump, fuel discharged from a high pressure pump is supplied to a fuel injection valve, and the pressure of the fuel discharged from the high pressure pump is measured. 2. Description of the Related Art An internal combustion engine that controls the amount of fuel discharged from a high-pressure pump so as to reach a target fuel pressure is known (see Japanese Patent Application Laid-Open No. 63-117150).
In this internal combustion engine, when the pressure of the fuel discharged from the high-pressure pump becomes higher than the target fuel pressure, the discharge amount of the high-pressure pump is reduced, and the pressure of the fuel discharged from the high-pressure pump becomes lower than the target fuel pressure. At times, the discharge amount of the high-pressure pump is increased, so that the pressure of the fuel discharged from the high-pressure pump is maintained at the target fuel pressure.
【０００３】[0003]
【発明が解決しようとする課題】ところがこの内燃機関
では低圧ポンプの吐出側を直接高圧ポンプの吸込み側に
接続している。しかしながらこのように低圧ポンプの吐
出側を直接高圧ポンプの吸込み側に接続すると高圧ポン
プの吐出量が多いときには高圧ポンプの吸込み側の燃料
圧が低下し、高圧ポンプの吐出量が少ないときには高圧
ポンプの吸込み側の燃料圧が上昇する。即ち、高圧ポン
プの吸込み側の燃料圧が大巾に変動することになる。However, in this internal combustion engine, the discharge side of the low pressure pump is directly connected to the suction side of the high pressure pump. However, when the discharge side of the low-pressure pump is directly connected to the suction side of the high-pressure pump, the fuel pressure on the suction side of the high-pressure pump decreases when the discharge amount of the high-pressure pump is large, and when the discharge amount of the high-pressure pump is small, the pressure of the high-pressure pump decreases. The fuel pressure on the suction side increases. That is, the fuel pressure on the suction side of the high-pressure pump fluctuates greatly.
【０００４】ところで高圧ポンプの吐出側の燃料圧がほ
ぼ一定の燃料圧、即ち目標燃料圧に維持されているとき
には高圧ポンプの吸込み側の燃料圧が低下すると高圧ポ
ンプから吐出される燃料量は減少し、高圧ポンプの吸込
み側の燃料圧が高くなると高圧ポンプから吐出される燃
料量は増大する。従って高圧ポンプから吐出された燃料
の圧力が目標燃料圧よりも低下したときに高圧ポンプの
吐出燃料圧を目標燃料圧まで上昇するために高圧ポンプ
の吐出量を増大させると高圧ポンプの吸込み側の燃料圧
が低いときには高圧ポンプの吐出燃料圧がなかなか目標
燃料圧に到達せず、これに対して高圧ポンプの吸込み側
の燃料圧が高いときには高圧ポンプの吐出燃料圧が一時
的に目標燃料圧を越え、次いで高圧ポンプの吐出燃料圧
は目標燃料圧に落ち着くまで変動を繰返すことになる。
即ち、低圧ポンプの吐出側を直接高圧ポンプの吸込み側
に接続すると高圧ポンプの吐出燃料圧を目標燃料圧に精
度よく制御するのが困難であるという問題を生ずる。When the fuel pressure on the discharge side of the high-pressure pump is maintained at a substantially constant fuel pressure, that is, the target fuel pressure, when the fuel pressure on the suction side of the high-pressure pump decreases, the amount of fuel discharged from the high-pressure pump decreases. However, when the fuel pressure on the suction side of the high-pressure pump increases, the amount of fuel discharged from the high-pressure pump increases. Therefore, when the pressure of the fuel discharged from the high-pressure pump drops below the target fuel pressure, the discharge amount of the high-pressure pump is increased to increase the discharge fuel pressure of the high-pressure pump to the target fuel pressure. When the fuel pressure is low, the discharge fuel pressure of the high-pressure pump does not easily reach the target fuel pressure, whereas when the fuel pressure on the suction side of the high-pressure pump is high, the discharge fuel pressure of the high-pressure pump temporarily exceeds the target fuel pressure. Then, the fuel pressure discharged from the high-pressure pump repeatedly fluctuates until it reaches the target fuel pressure.
That is, if the discharge side of the low-pressure pump is directly connected to the suction side of the high-pressure pump, there arises a problem that it is difficult to accurately control the discharge fuel pressure of the high-pressure pump to the target fuel pressure.
【０００５】[0005]
【課題を解決するための手段】上記問題点を解決するた
めに本発明によれば低圧ポンプから吐出された燃料を高
圧ポンプに供給し、高圧ポンプから吐出された燃料を燃
料噴射弁に供給し、高圧ポンプから吐出された燃料の圧
力を計測してこの圧力が目標燃料圧となるように高圧ポ
ンプから吐出される燃料量を制御するようにした内燃機
関の燃料噴射装置において、低圧ポンプと高圧ポンプ間
に高圧ポンプに供給される燃料圧を一定に維持するため
の圧力調整弁を設け、高圧ポンプから溢流した溢流燃料
を低圧ポンプと高圧ポンプ間に供給するようにしてい
る。 According to the present invention, a fuel discharged from a low-pressure pump is supplied to a high-pressure pump, and a fuel discharged from the high-pressure pump is supplied to a fuel injection valve. In a fuel injection device for an internal combustion engine, which measures the pressure of fuel discharged from a high-pressure pump and controls the amount of fuel discharged from the high-pressure pump so that the pressure becomes a target fuel pressure, a low-pressure pump and a high-pressure the pressure regulating valve for maintaining the fuel pressure supplied to high-pressure pump constant at between pump provided, the overflow fuel which has overflowed from the high-pressure pump
Is supplied between the low pressure pump and the high pressure pump.
You.
【０００６】[0006]
【作用】圧力調整弁によって高圧ポンプの吸込み側の燃
料圧が一定に維持されると共に高圧ポンプから溢流した
溢流燃料が低圧ポンプと高圧ポンプ間に供給される。The fuel pressure on the suction side of the high pressure pump is maintained constant by the pressure regulating valve, and the overflow fuel overflowing from the high pressure pump is supplied between the low pressure pump and the high pressure pump.
【０００７】[0007]
【実施例】図１を参照すると、１は燃料タンク、２は電
動式の低圧ポンプ、３は機関駆動の高圧ポンプ、４は高
圧燃料で満たされたリザーバタンク、５は燃焼室内に燃
料を噴射するために機関本体６に取付けられた燃料噴射
弁を夫々示す。低圧ポンプ２の吸込み側は燃料通路７を
介して燃料タンク１に連結され、低圧ポンプ２の吐出側
は燃料通路８を介して高圧ポンプ３の吸込み側に接続さ
れる。燃料通路８内には高圧ポンプ３の吸込み側に加わ
る燃料圧を２kg／cm2 から４kg／cm2 程度の一定圧に維
持するための圧力調整弁９が設けられ、余剰の燃料は燃
料通路１０を介して燃料タンク１に返戻される。Referring to FIG. 1, 1 is a fuel tank, 2 is an electric low pressure pump, 3 is an engine driven high pressure pump, 4 is a reservoir tank filled with high pressure fuel, and 5 is a fuel tank in the combustion chamber.
1 shows a fuel injection valve attached to an engine body 6 for injecting fuel. The suction side of the low pressure pump 2 is connected to the fuel tank 1 via a fuel passage 7, and the discharge side of the low pressure pump 2 is connected to the suction side of the high pressure pump 3 via a fuel passage 8. A pressure regulating valve 9 for maintaining the fuel pressure applied to the suction side of the high-pressure pump 3 at a constant pressure of about 2 kg / cm 2 to 4 kg / cm 2 is provided in the fuel passage 8. Is returned to the fuel tank 1 via.
【０００８】一方、高圧ポンプ３の吐出側は燃料通路１
１を介してリザーバタンク４に連結され、この燃料通路
１１内にはリザーバタンク４内の燃料圧が一定圧を越え
たときに開弁する安全弁１２が配置される。安全弁１２
が開弁するとリザーバタンク４内の燃料は燃料通路１３
を介して燃料タンク１に返戻される。高圧ポンプ３内に
は高圧ポンプ３内に供給された燃料の溢流を制御するた
めの溢流制御弁１４が配置されており、この溢流制御弁
１４は燃料通路１５を介して低圧ポンプ２と圧力調整弁
９間の燃料通路８に連結される。この燃料通路１５内に
は燃料圧の脈動を減衰させるための容積部１６が形成さ
れている。On the other hand, the discharge side of the high-pressure pump 3
A safety valve 12 is connected to the reservoir tank 4 through a valve 1 and opens in the fuel passage 11 when the fuel pressure in the reservoir tank 4 exceeds a predetermined pressure. Safety valve 12
When the valve is opened, the fuel in the reservoir tank 4 is released from the fuel passage 13.
Is returned to the fuel tank 1 via. An overflow control valve 14 for controlling the overflow of the fuel supplied to the high pressure pump 3 is disposed in the high pressure pump 3, and the overflow control valve 14 is connected to the low pressure pump 2 via a fuel passage 15. And the pressure control valve 9 is connected to the fuel passage 8. In the fuel passage 15, a volume 16 for damping the pulsation of the fuel pressure is formed.
【０００９】リザーバタンク４内には８０kg／cm2 から
２００kg／cm2 程度の圧力の燃料が蓄積されており、リ
ザーバタンク４内の燃料は各燃料通路１７を介して対応
する燃料噴射弁５に連結される。なお、図１には各燃料
通路内における燃料の流通方向が矢印で示されている。
一方、リザーバタンク４内にはリザーバタンク４内の燃
料圧を検出するための圧力センサ１８が取付けられてお
り、この圧力センサ１８の検出信号は電子制御装置１９
に入力される。溢流制御弁１４は圧力センサ１８の検出
信号に基いて電子制御装置１９の出力信号により制御さ
れる。Fuel having a pressure of about 80 kg / cm 2 to 200 kg / cm 2 is accumulated in the reservoir tank 4, and the fuel in the reservoir tank 4 is supplied to the corresponding fuel injection valve 5 through each fuel passage 17. Be linked. In FIG. 1, the flow direction of the fuel in each fuel passage is indicated by an arrow.
On the other hand, a pressure sensor 18 for detecting a fuel pressure in the reservoir tank 4 is mounted in the reservoir tank 4, and a detection signal of the pressure sensor 18 is transmitted to an electronic control unit 19.
Is input to The overflow control valve 14 is controlled by an output signal of an electronic control unit 19 based on a detection signal of a pressure sensor 18.
【００１０】図２に高圧ポンプ３の一部を示す。図２に
示されるように高圧ポンプ３は機関駆動のカムによって
上下動せしめられるプランジャ２０を具備し、このプラ
ンジャ２０によって加圧室２１内の燃料が加圧される。
この加圧室２１は逆止弁２２を介して燃料通路１１に連
結されており、ソレノイド２３によって制御される溢流
制御弁１４を介して燃料通路１５に連結されている。ま
た、プランジャ２０が下降したときには燃料通路８が加
圧室２１内に開口し、このとき燃料通路８から加圧室２
１に燃料が供給される。図１からわかるようにこの燃料
通路８内の燃料圧は一定に維持されており、従って燃料
通路８が加圧室２１内に開口すると加圧室２１内は一定
圧の燃料で満たされる。FIG. 2 shows a part of the high-pressure pump 3. As shown in FIG. 2, the high-pressure pump 3 includes a plunger 20 that can be moved up and down by a cam driven by the engine, and the plunger 20 pressurizes the fuel in the pressurizing chamber 21.
The pressurizing chamber 21 is connected to the fuel passage 11 via a check valve 22, and is connected to the fuel passage 15 via an overflow control valve 14 controlled by a solenoid 23. When the plunger 20 is lowered, the fuel passage 8 opens into the pressurizing chamber 21. At this time, the fuel passage 8
1 is supplied with fuel. As can be seen from FIG. 1, the fuel pressure in the fuel passage 8 is kept constant. Therefore, when the fuel passage 8 is opened into the pressurizing chamber 21, the inside of the pressurizing chamber 21 is filled with fuel at a constant pressure.
【００１１】次いでプランジャ２０は上昇せしめられる
がこのとき溢流制御弁１４は開弁しており、従って加圧
室２１内の燃料は溢流制御弁１４を介して燃料通路１５
内に溢流せしめられる。次いでプランジャ２０が更に上
昇すると溢流制御弁１４が閉弁せしめられ、斯くしてプ
ランジャ２０による加圧室２１内の燃料の加圧作用が開
始される。次いで加圧室２１の燃料圧がリザーバタンク
４内の燃料圧よりも高くなると加圧室２１内の燃料がリ
ザーバタンク４内に供給される。次いでプランジャ２０
が上死点に達すると溢流制御弁１４が再び開弁せしめら
れる。従って溢流制御弁１４が閉弁している期間を制御
することによって高圧ポンプ３から燃料通路１１内に吐
出される燃料量を制御できることがわかる。Next, the plunger 20 is raised. At this time, the overflow control valve 14 is open, so that the fuel in the pressurizing chamber 21 is supplied to the fuel passage 15 through the overflow control valve 14.
It overflows inside. Next, when the plunger 20 further rises, the overflow control valve 14 is closed, and the pressurizing action of the fuel in the pressurizing chamber 21 by the plunger 20 is started. Next, when the fuel pressure in the pressurizing chamber 21 becomes higher than the fuel pressure in the reservoir tank 4, the fuel in the pressurizing chamber 21 is supplied into the reservoir tank 4. Then plunger 20
Reaches the top dead center, the overflow control valve 14 is opened again. Therefore, it is understood that the amount of fuel discharged from the high-pressure pump 3 into the fuel passage 11 can be controlled by controlling the period during which the overflow control valve 14 is closed.
【００１２】高圧ポンプ３は実際には互いに逆方向に往
復動する一対のプランジャ２０を具備しており、各プラ
ンジャ２０は機関のクランクシャフトが一回転する毎に
一往復せしめられる。この高圧ポンプ３では溢流制御弁
１４が開弁するクランク角は固定されており、溢流制御
弁１４が閉弁するクランク角を制御することによって溢
流制御弁１４の閉弁期間が制御される。例えばリザーバ
タンク４内の燃料圧が目標燃料圧よりも低くなったとき
には溢流制御弁１４が閉弁するクランク角が一定クラン
ク角度だけ早められ、それによって高圧ポンプ３から吐
出される燃料量が増大せしめられる。これに対してリザ
ーバタンク４内の燃料圧が目標燃料圧よりも高くなった
ときには溢流制御弁１４が閉弁するクランク角が一定ク
ランク角度だけ遅くされ、それによって高圧ポンプ３か
ら吐出される燃料量が減少せしめられる。このようにし
てリザーバタンク４内の燃料圧が目標燃料圧に維持され
る。The high-pressure pump 3 actually has a pair of plungers 20 which reciprocate in opposite directions, and each plunger 20 is made to reciprocate once each time the crankshaft of the engine makes one revolution. In this high-pressure pump 3, the crank angle at which the overflow control valve 14 opens is fixed, and the valve closing period of the overflow control valve 14 is controlled by controlling the crank angle at which the overflow control valve 14 closes. You. For example, when the fuel pressure in the reservoir tank 4 becomes lower than the target fuel pressure, the crank angle at which the overflow control valve 14 closes is advanced by a certain crank angle, thereby increasing the amount of fuel discharged from the high-pressure pump 3. I'm sullen. On the other hand, when the fuel pressure in the reservoir tank 4 becomes higher than the target fuel pressure, the crank angle at which the overflow control valve 14 closes is delayed by a certain crank angle, whereby the fuel discharged from the high pressure pump 3 The amount is reduced. Thus, the fuel pressure in the reservoir tank 4 is maintained at the target fuel pressure.
【００１３】一方、図１において鎖線で囲まれた部分は
図３に示されるように金属ブロック３０内に形成されて
いる。即ち、金属ブロック３０内には圧力調整弁９の弁
室３１が形成されており、金属ブロック３０内をこの弁
室３１内に通ずる各燃料通路８および燃料通路１５が延
びている。また、金属ブロック３０内には安全弁１２の
弁室３２が形成されており、金属ブロック３０内をこの
弁室３２内に通ずる各燃料通路１１が延びている。On the other hand, a portion surrounded by a chain line in FIG. 1 is formed in a metal block 30 as shown in FIG. That is, a valve chamber 31 of the pressure regulating valve 9 is formed in the metal block 30, and the fuel passages 8 and the fuel passages 15 that extend through the metal block 30 into the valve chamber 31 extend. Further, a valve chamber 32 of the safety valve 12 is formed in the metal block 30, and each fuel passage 11 extending into the valve chamber 32 in the metal block 30 extends.
【００１４】図３に示されるように圧力調整弁９はダイ
アフラム３３と、ダイアフラム３３に連結された弁体３
４と、ダイアフラム押圧用圧縮ばね３５とを具備する。
高圧ポンプ３の溢流制御弁１４を介して燃料通路１５内
に溢流した燃料は低圧ポンプ２から吐出された燃料と金
属ブロック３０内の燃料通路８内において合流し、次い
で弁室３１内に流入する。次いでこの燃料は燃料通路８
を通って高圧ポンプ３に供給される。弁室３１内の燃料
圧が圧縮ばね３５による設定圧を越えると弁体３４が燃
料通路１０を開口し、斯くして弁室３１内の燃料は燃料
通路１０を介して燃料タンク１に返戻される。As shown in FIG. 3, the pressure regulating valve 9 includes a diaphragm 33 and a valve body 3 connected to the diaphragm 33.
4 and a diaphragm pressing compression spring 35.
The fuel that has overflowed into the fuel passage 15 through the overflow control valve 14 of the high-pressure pump 3 merges with the fuel discharged from the low-pressure pump 2 in the fuel passage 8 in the metal block 30 and then into the valve chamber 31. Inflow. Next, the fuel is supplied to the fuel passage 8.
And supplied to the high-pressure pump 3. When the fuel pressure in the valve chamber 31 exceeds the pressure set by the compression spring 35, the valve element 34 opens the fuel passage 10, and the fuel in the valve chamber 31 is returned to the fuel tank 1 via the fuel passage 10. You.
【００１５】一方、安全弁１２は弁体３６と、弁体押圧
用圧縮ばね３７とを具備する。高圧ポンプ３から吐出さ
れた燃料は燃料通路１１を介して弁室３２内に流入し、
次いで燃料通路１１を介してリザーバタンク４内に供給
される。弁室３２内の燃料圧が圧縮ばね３７による設定
圧を越えると弁体３６が開弁し、斯くしてリザーバタン
ク４内の燃料が燃料通路１１、弁室３２および燃料通路
１３を介して燃料タンク１内に返戻される。On the other hand, the safety valve 12 has a valve element 36 and a compression spring 37 for pressing the valve element. The fuel discharged from the high-pressure pump 3 flows into the valve chamber 3 in the 2 through the fuel passage 11,
Next, the fuel is supplied into the reservoir tank 4 through the fuel passage 11. When the fuel pressure in the valve chamber 32 exceeds the pressure set by the compression spring 37, the valve element 36 opens, so that the fuel in the reservoir tank 4 flows through the fuel passage 11, the valve chamber 32 and the fuel passage 13 to the fuel. It is returned into the tank 1.
【００１６】ところでリザーバタンク４内の燃料圧が目
標燃料圧であるときに燃料噴射弁５から燃料噴射が行わ
れるとリザーバタンク４内の燃料圧は目標燃料圧よりも
低くなる。このとき燃料噴射弁５から噴射された燃料量
だけ高圧ポンプ３からリザーバタンク４内に燃料を供給
してやればリザーバタンク４内の燃料圧をただちに目標
燃料圧とすることができる。この場合燃料噴射によるリ
ザーバタンク４内の燃料圧の低下量は燃料噴射量に比例
するのでリザーバタンク４内の燃料圧の低下量に対応し
た量の燃料を高圧ポンプ３からリザーバタンク４内に供
給してやればリザーバタンク４内の燃料圧をただちに目
標燃料圧とすることができることになる。When fuel is injected from the fuel injection valve 5 while the fuel pressure in the reservoir tank 4 is at the target fuel pressure, the fuel pressure in the reservoir tank 4 becomes lower than the target fuel pressure. At this time, if fuel is supplied from the high-pressure pump 3 into the reservoir tank 4 by the amount of fuel injected from the fuel injection valve 5, the fuel pressure in the reservoir tank 4 can be immediately set to the target fuel pressure. The amount of fuel corresponding to the decrease amount of the fuel pressure in the reservoir tank 4 In this case the amount of decrease in fuel pressure in the re <br/> Zabatanku 4 that by the fuel injection is proportional to the amount of fuel injected from the high-pressure pump 3 If the fuel is supplied into the reservoir tank 4, the fuel pressure in the reservoir tank 4 can be immediately set to the target fuel pressure.
【００１７】ところで本発明による実施例では図１に示
されるように低圧ポンプ２と高圧ポンプ３間に圧力調整
弁９が配置されており、従って高圧ポンプ３の吸込み側
の燃料圧は一定に維持されている。一方、リザーバタン
ク４内は目標燃料圧近くに維持されており、従って高圧
ポンプ３の吸込み側と吐出側の圧力差はほぼ一定に維持
されている。このように高圧ポンプ３の吸込み側と吐出
側の圧力差がほぼ一定に維持されていると溢流制御弁１
４の閉弁時期が一定クランク角度だけ変化せしめられた
ときの高圧ポンプ３の吐出量はほぼ一定量だけ変化す
る。従って溢流制御弁１４が閉弁するクランク角をリザ
ーバタンク４内の燃料圧の低下量に比例して変化させれ
ばリザーバタンク４内の燃料圧をただちに目標燃料圧と
することができる。このように低圧ポンプ２と高圧ポン
プ３間に圧力調整弁９を配置するとリザーバタンク４内
の燃料圧を精度よく目標燃料圧に維持できることにな
る。In the embodiment according to the present invention, as shown in FIG. 1, a pressure regulating valve 9 is arranged between the low-pressure pump 2 and the high-pressure pump 3, so that the fuel pressure on the suction side of the high-pressure pump 3 is kept constant. Have been. On the other hand, the inside of the reservoir tank 4 is maintained close to the target fuel pressure, so that the pressure difference between the suction side and the discharge side of the high-pressure pump 3 is maintained substantially constant. As described above, when the pressure difference between the suction side and the discharge side of the high-pressure pump 3 is maintained substantially constant, the overflow control valve 1
The discharge amount of the high-pressure pump 3 when the valve closing timing of No. 4 is changed by a constant crank angle changes by a substantially constant amount. Therefore, if the crank angle at which the overflow control valve 14 closes is changed in proportion to the amount of decrease in the fuel pressure in the reservoir tank 4, the fuel pressure in the reservoir tank 4 can be immediately set to the target fuel pressure. By arranging the pressure regulating valve 9 between the low-pressure pump 2 and the high-pressure pump 3 as described above, the fuel pressure in the reservoir tank 4 can be accurately maintained at the target fuel pressure.
【００１８】一方、図１に示されるように高圧ポンプ３
の溢流制御弁１４を介して燃料通路１５内に溢流された
燃料は低圧ポンプ２と圧力調整弁９間の燃料通路８に返
戻される。このとき例えば溢流制御弁１４を介して溢流
された燃料を燃料タンク１内に直接戻すようにすると燃
料圧が大気圧まで低下するために燃料中に気泡が発生し
てしまう。しかしながら低圧ポンプ２と圧力調整弁９間
の燃料通路８内の圧力は高いので上述したように溢流燃
料をこの燃料通路８内に戻せば燃料圧が大気圧まで低下
せず、斯くして燃料中に気泡が発生するのを阻止するこ
とができる。また、溢流燃料を燃料通路８内に返戻すれ
ばこの返戻した燃料分だけ低圧ポンプ２の吐出容量を小
さくすることができる。云い換えれば溢流燃料を直接燃
料タンク１に返戻させるようにした場合に比べて容量の
小さな低圧ポンプ２を用いることができる。On the other hand, as shown in FIG.
The fuel that has overflowed into the fuel passage 15 through the overflow control valve 14 is returned to the fuel passage 8 between the low-pressure pump 2 and the pressure regulating valve 9. At this time, for example, if the fuel overflowed through the overflow control valve 14 is directly returned to the fuel tank 1, the fuel pressure drops to the atmospheric pressure, and bubbles are generated in the fuel. However, since the pressure in the fuel passage 8 between the low-pressure pump 2 and the pressure regulating valve 9 is high, if the overflow fuel is returned into the fuel passage 8 as described above, the fuel pressure does not decrease to the atmospheric pressure. The generation of air bubbles therein can be prevented. If the overflow fuel is returned into the fuel passage 8, the discharge capacity of the low-pressure pump 2 can be reduced by the returned fuel. In other words, the low-pressure pump 2 having a smaller capacity can be used as compared with the case where the overflow fuel is directly returned to the fuel tank 1.
【００１９】一方、低圧ポンプ２から燃料通路８内に吐
出された燃料の温度および溢流制御弁１４を介して燃料
通路１５内に吐出された燃料の温度は比較的低いが高圧
ポンプ３から燃料通路１１内に吐出された燃料の温度は
かなり高温となる。ところが図３に示されるように各燃
料通路８，１１，１５は金属ブロック３０内を延びてい
るので燃料通路１１内を流れる高温の燃料は燃料通路
８，１５内を流れる低温の燃料によって良好に冷却され
ることになる。なお、冷却効率を高めるために金属ブロ
ック３０周りにフィンを形成することもできる。また、
圧力調整弁９を例えばステー等により支持しておくと圧
力調整弁９の作動時に圧力調整弁９は大きな振動騒音を
発生する。しかしながら図３に示すように圧力調整弁９
を比較的大きな質量を有する金属ブロック３０内に組込
むと圧力調整弁９の作動時に圧力調整弁９が大きな振動
騒音を発生しなくなる。On the other hand, the temperature of the fuel discharged from the low-pressure pump 2 into the fuel passage 8 and the temperature of the fuel discharged into the fuel passage 15 through the overflow control valve 14 are relatively low, but the temperature of the fuel discharged from the high-pressure pump 3 is relatively low. The temperature of the fuel discharged into the passage 11 becomes considerably high. However, as shown in FIG. 3, since the fuel passages 8, 11, and 15 extend in the metal block 30, the high-temperature fuel flowing in the fuel passages 11 is favorably reduced by the low-temperature fuel flowing in the fuel passages 8, 15. It will be cooled. Note that fins can be formed around the metal block 30 to increase the cooling efficiency. Also,
If the pressure regulating valve 9 is supported by, for example, a stay, the pressure regulating valve 9 generates a large vibration noise when the pressure regulating valve 9 is operated. However, as shown in FIG.
Is incorporated in the metal block 30 having a relatively large mass, the pressure regulating valve 9 does not generate large vibration noise when the pressure regulating valve 9 is operated.
【００２０】[0020]
【発明の効果】低圧ポンプと高圧ポンプ間に圧力調整弁
を設けることにより高圧ポンプの吸込み側の燃料圧を一
定に維持することができ、しかも高圧ポンプから溢流し
た溢流燃料を低圧ポンプと高圧ポンプ間に供給すること
により燃料中に気泡が発生するのを阻止することができ
るので高圧ポンプから吐出された燃料の圧力を目標燃料
圧に精度よく制御することができる。The pressure regulating valve is provided between the low pressure pump and the high pressure pump.
The fuel pressure on the suction side of the high-pressure pump
Constant, and overflow from the high pressure pump
Spilled fuel between the low and high pressure pumps
Can prevent the formation of bubbles in the fuel
Therefore, the pressure of the fuel discharged from the high-pressure pump can be accurately controlled to the target fuel pressure.
【図１】図解的に示した燃料噴射装置の全体図である。FIG. 1 is an overall view of a fuel injection device schematically shown.
【図２】高圧ポンプの一部の側面断面図である。FIG. 2 is a side sectional view of a part of the high-pressure pump.
【図３】金属ブロックの側面断面図である。FIG. 3 is a side sectional view of a metal block.
２…低圧ポンプ ３…高圧ポンプ ４…リザーバタンク ５…燃料噴射弁 ７，８，１０，１１，１３，１５，１７…燃料通路 ９…圧力調整弁 2 ... Low pressure pump 3 ... High pressure pump 4 ... Reservoir tank 5 ... Fuel injection valve 7,8,10,11,13,15,17 ... Fuel passage 9 ... Pressure regulating valve
Claims (1)
ンプに供給し、高圧ポンプから吐出された燃料を燃料噴
射弁に供給し、高圧ポンプから吐出された燃料の圧力を
計測してこの圧力が目標燃料圧となるように高圧ポンプ
から吐出される燃料量を制御するようにした内燃機関の
燃料噴射装置において、低圧ポンプと高圧ポンプ間に高
圧ポンプに供給される燃料圧を一定に維持するための圧
力調整弁を設け、高圧ポンプから溢流した溢流燃料を低
圧ポンプと高圧ポンプ間に供給するようにした内燃機関
の燃料噴射装置。The fuel discharged from a low pressure pump is supplied to a high pressure pump, the fuel discharged from a high pressure pump is supplied to a fuel injection valve, and the pressure of the fuel discharged from the high pressure pump is measured. In a fuel injection device for an internal combustion engine in which the amount of fuel discharged from a high pressure pump is controlled to reach a target fuel pressure, in order to maintain a constant fuel pressure supplied to the high pressure pump between the low pressure pump and the high pressure pump. Pressure control valve to reduce the overflow fuel overflowing from the high pressure pump.
A fuel injection device for an internal combustion engine which is supplied between a pressure pump and a high pressure pump .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03227189A JP3074830B2 (en) | 1991-09-06 | 1991-09-06 | Fuel injection device for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03227189A JP3074830B2 (en) | 1991-09-06 | 1991-09-06 | Fuel injection device for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05321782A JPH05321782A (en) | 1993-12-07 |
| JP3074830B2 true JP3074830B2 (en) | 2000-08-07 |
Family
ID=16856888
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03227189A Expired - Fee Related JP3074830B2 (en) | 1991-09-06 | 1991-09-06 | Fuel injection device for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3074830B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5558068A (en) * | 1994-05-31 | 1996-09-24 | Zexel Corporation | Solenoid valve unit for fuel injection apparatus |
| DE19727785B4 (en) * | 1997-06-30 | 2006-04-13 | Robert Bosch Gmbh | Flow control valve for controlling liquids |
| JPH1150933A (en) * | 1997-08-01 | 1999-02-23 | Zexel Corp | Accumulator fuel injection system |
-
1991
- 1991-09-06 JP JP03227189A patent/JP3074830B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05321782A (en) | 1993-12-07 |
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