EP0645534B1 - Fuel-injection pump for turbocharged diesel engine - Google Patents
Fuel-injection pump for turbocharged diesel engine Download PDFInfo
- Publication number
- EP0645534B1 EP0645534B1 EP94115201A EP94115201A EP0645534B1 EP 0645534 B1 EP0645534 B1 EP 0645534B1 EP 94115201 A EP94115201 A EP 94115201A EP 94115201 A EP94115201 A EP 94115201A EP 0645534 B1 EP0645534 B1 EP 0645534B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- plunger
- sub
- port
- fuel
- fuel injection
- 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 - Lifetime
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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
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/20—Varying fuel delivery in quantity or timing
- F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
- F02M59/26—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders
- F02M59/265—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders characterised by the arrangement or form of spill port of spill contour on the piston
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- 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
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/20—Varying fuel delivery in quantity or timing
- F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
- F02M59/26—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Definitions
- the present invention relates to a fuel injection pump for a diesel engine as known from US-A-2 361 817. It is preferably fitted with a turbo-charger, and more particularly it refers to a fuel-injection pump for a turbocharged diesel engine that has an injection compensation mechanism.
- exhaust gas from the combustion chamber (engine cylinder) is used to compress intake air which is then supplied to the engine to increase the power of the engine.
- changes in the boost pressure provided by the turbocharger is a function of the fuel injection pump speed in rpm (N) and injection quantity or load (Q).
- a turbocharged diesel engine 1 has a engine body 2, a piston 3, a turbocharger 4, a governor 5 and a fuel injection pump 6.
- a crankshaft 8 is turned by the reciprocating movement of the piston 3 in a combustion chamber 7.
- the turbocharger 4 uses the exhaust gas from an exhaust manifold 9 to compress intake air, and the air thus compressed is delivered to the combustion chamber 7 via an intake manifold 10.
- the governor 5 controls the fuel injection quantity in accordance with the speed (rpm) of the turbocharged diesel engine 1.
- the fuel injection pump 6 has a camshaft 11 driven by the crankshaft 8, an injection pipe 12, and an injection nozzle 13 arranged in opposition to the combustion chamber 7.
- One method that is commonly used to evaluate the performance of an engine such as the turbocharged diesel engine 1 consists of measuring the level of black smoke that is generated when the engine is subjected to sudden acceleration from a low idle.
- a problem with the diesel engine 1 is that sharply accelerating the engine from a low idle causes an excessive quantity of fuel to be injected and black smoke to be produced. This is explained below.
- the graph of Figure 8 shows the relationship between pump speed N (or engine speed) and injection quantity Q.
- the relationship in the case of an engine that does not have a turbocharger 4 is indicated by a broken line, while the higher injection quantity Q of the engine 1 equipped with the turbocharger 4 is indicated by a solid line. Injecting more than the proper quantity of fuel during low-speed operation causes black smoke to be produced.
- a device known as a boost compensator (not shown) was used to control the relationship between turbocharger 4 boost pressure, and pump speed N and injection quantity Q.
- the boost compensator suppresses the emission of black smoke during low-speed operation by reducing injection quantity Q (refer to the "Zone of injection quantity control by boost compensator" in Figure 9). That is, when the boost pressure provided by the turbocharger 4 is low, the boost compensator limits the generation of black smoke to a certain level by setting the control rack position R further in.
- turbocharged diesel engines not equipped with a boost compensator particularly turbocharged diesel engines used for industrial applications, the injection quantity Q becomes excessive and all turns into black smoke, creating a major problem with respect to engine evaluation. Furthermore, most turbocharged diesel engines 1 are small units. In order to newly equip such engines with a boost compensator, it is necessary to alter the linkage (not shown) used for the governor 5. Also, in the case of turbocharged diesel engines in which the governor 5 is not directly connected to the fuel injection pump 6 but is provided on the engine side, the limited space also makes it difficult to fit a boost compensator.
- An object of the present invention is to provide a fuel-injection pump for a turbocharged diesel engine that is not equipped with a boost compensator, and which by reducing the fuel injection quantity is able to suppress the generation of black smoke when the engine is subjected to sudden acceleration from a low-speed state, or to low speed, high load operation.
- the fuel-injection pump for a turbocharged diesel engine has a plunger barrel in which are formed a large diameter main port and a small diameter sub-port, and a plunger in which is formed an upper sub-lead able to communicate with the sub-port.
- the fuel-injection pump according to this invention can provide the same functionality as a boost compensator, and therefore can improve engine performance without any changes to the principle parts of conventional diesel engines or fuel injection pumps.
- the injection quantity characteristics can be adjusted based on the difference between the static effective stroke (low speed) and dynamic effective stroke (high speed) with a fixed control rack position.
- FIG. 1 is a cross-sectional view of the fuel-injection pump 20 for a turbocharged diesel engine
- Figure 2 is a cross-sectional view of the main parts of portion II of Figure 1.
- the fuel injection pump 20 has a pump housing 21, a cam 22 affixed to a camshaft 11 ( Figure 7), an injection quantity control rack 23, a plunger barrel 24, a plunger 25, a delivery valve 26 and a delivery valve holder 27.
- the cam 22 is driven via the camshaft 11 by a crankshaft 8 of a diesel engine 1, thereby causing the plunger 25 to be reciprocated vertically via tappet roller 28.
- the control rack 23 is linked to the accelerator (not shown) via governor 5 ( Figure 7). Moving the control rack 23 in a direction normal to the drawing sheet via control sleeve 29 rotates the plunger 25 axially through a prescribed angle.
- the plunger barrel 24 is fixed within the pump housing 21 to which it is attached.
- the plunger 25 is accommodated inside the plunger barrel 24 so that the plunger 25 can reciprocate and rotate therein.
- a fuel reserve chamber 30 is defined by the plunger 25 and the pump housing 21, and the space between the plunger barrel 24 and the delivery valve 26 forms a fuel pressure chamber 31.
- a main port 32 and a sub-port 33 through which fuel is drawn in and expelled.
- the upper edge 32A of the main port 32 and the upper edge 33A of the sub-port 33 are formed at the same height or horizontally at the same position and separated in the circumferential direction by 180 degrees.
- the main port 32 and sub-port 33 may also be formed so that the upper edge 33A is lower than the upper edge 32A.
- Fuel from the fuel reserve chamber 30 is sucked in by the reciprocation of the plunger 25 in the plunger barrel 24 and compressed in the fuel pressure chamber 31.
- the delivery valve 26 opens, the fuel is delivered under pressure via injection pipe 12 ( Figure 7) to the injection nozzle 13.
- Figure 3 is a diagram of the leads at the top part of the plunger 25, showing the mutual positional relationship between the main port 32 and sub-port 33.
- Formed in the top part of the plunger 25 are a vertical fuel passage 34 that communicates with the pressure chamber 31, an inclined lead 35 that communicates with the vertical fuel passage 34, and an upper sub-lead 36 that communicates with the pressure chamber 31.
- the upper sub-lead 36 can oppose the sub-port 33 from normal load to startup, and the main port 32 can oppose the upper edge 25A of the plunger 25.
- normal load encompasses a range of operation extending from low speed operation such as idling, to high speed operation and high idling (reduction of fuel injection quantity by the governor 5 when high speed, high load rated rotational speed zone is exceeded), under high loads and low loads other than at startup.
- the stroke of the plunger 25 from bottom dead center to the start of fuel delivery is a prestroke.
- the depth or height of the upper sub-lead 36 is preflow stroke L1.
- the stroke from the closing of the sub-port 33 to the opening of the main port 32 is static (low speed operation) effective prestroke L2, and the stroke from the closing to the opening of main port 32 is dynamic (high speed operation) effective stroke L3.
- the main port 32 When the engine is under normal load operation, the main port 32 is opposite the upper edge 25A of the plunger 25 and the sub-port 33 is opposite the upper sub-lead 36. At idling and other low speed operation, the position of the main port 32 is further to the left relative to the inclined lead 35 shown in Figure 3, reducing the effective stroke, and as shown in Figure 4, the sub-port 33 is in alignment with the upper sub-lead 36, so the delivery of fuel substantially starts when the sub-port 33 is closed by the upper edge 36A of the upper sub-lead 36.
- Figure 6 is a graph of the N-Q characteristics of the pump 20 with this preflow effect plunger 25.
- the preflow effect plunger 25 results in the N-Q characteristics indicated in Figure 6 by the solid lines rising to the right (with the control rack 23 at the same position, injection quantity increases at the high speed side).
- the broken lines indicate the results obtained with a conventional plunger not having an upper sub-lead 36.
- the fuel injection pump 20 has a fuel injection quantity suppressing effect that is the equivalent of the injection quantity suppressing effect provided by a boost compensator, as indicated by the "Zone of injection quantity control by boost compensator" in Figure 9.
- the fuel injection pump 20 can prevent the generation of black smoke caused by an excessive quantity of fuel injection by holding the fuel injection quantity to the appropriate level.
- a conventional fuel injection pump can be given this black smoke generation prevention effect without altering the basic pump arrangement.
- a plunger having an upper sub-lead for a sub-port is used instead of a boost compensator.
- the plunger be used in place of a standard plunger, whereby it enables the generation of black smoke to be kept to a low level without any external change to the fuel injection pump or diesel engine.
- the boost compensator can be omitted and the governor linkage therefore simplified.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
- High-Pressure Fuel Injection Pump Control (AREA)
Description
Claims (3)
- A fuel injection pump for a turbocharged diesel engine, said engine having a turbocharger,a piston driven by combustion in a combustion chamber of intake air supercharged by the turbocharger,a crankshaft rotated by the driving of the piston,a governor able to control a fuel injection quantity in accordance with a differential between a rotational speed of the crankshaft and a set target rotational speed, said fuel injection pump comprising:a pump housing,a cam (22) driven by rotation of the crankshaft (11),a plunger barrel (24) that is affixed to the pump housing and in which are formed intake and exhaust ports that communicate with a fuel reserve chamber, said intake and exhaust ports being constituted by a large diameter main port (32) and a small diameter sub-port (33) arranged so that the upper edge (33A) of the sub-port is below or at the same height as the upper edge (32A) of the main port,a plunger (25) disposed within the plunger barrel that can be moved reciprocally by the cam and rotated by a control rack operated in conjunction with the governor,an inclined lead (35) formed on the plunger at a position that permits communication with the intake and exhaust ports,an upper sub-lead (36) formed as a recess on the head portion of the plunger (25) that is able to communicate with the sub-port (33) over a prescribed range of rotation by the plunger, and which permits the sub-port (33) to communicate with the upper sub-lead (36) even when the main port (32) is closed by an upper edge of the plunger, anda fuel pressure chamber formed between the plunger and the plunger barrel into which fuel is sucked in from the fuel reserve chamber and delivered under pressure by the reciprocating movement of the plunger,
said ports and sub-lead are arranged in such a way that in a high load position of the plunger (25) the main port (32) is opened and closed by the upper edge (25A) of the plunger and the sub-port (33) is opened and closed by the upper sub-lead (36). - A fuel injection pump according to claim 1, wherein there is provided no boost compensator in which, when the boost pressure produced by the turbocharger is low the fuel injection quantity is limited by inserting the control rack further in.
- A fuel injection pump according to claim 1, wherein the main port is able to communicate with the inclined lead over a prescribed range of rotation by the plunger.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP263055/93 | 1993-09-28 | ||
JP5263055A JPH0797967A (en) | 1993-09-28 | 1993-09-28 | Fuel injection pump for diesel engine equipped with turbocharger |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0645534A1 EP0645534A1 (en) | 1995-03-29 |
EP0645534B1 true EP0645534B1 (en) | 1998-03-04 |
Family
ID=17384236
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94115201A Expired - Lifetime EP0645534B1 (en) | 1993-09-28 | 1994-09-27 | Fuel-injection pump for turbocharged diesel engine |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0645534B1 (en) |
JP (1) | JPH0797967A (en) |
KR (1) | KR960010295B1 (en) |
DE (1) | DE69408760T2 (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2361817A (en) * | 1940-06-10 | 1944-10-31 | Adolph Saurer Sa | Fuel injection pump for internalcombustion engines |
JPS5813134A (en) * | 1981-07-18 | 1983-01-25 | Nippon Soken Inc | Safety device for supercharging diesel engine |
-
1993
- 1993-09-28 JP JP5263055A patent/JPH0797967A/en active Pending
-
1994
- 1994-09-27 KR KR1019940024304A patent/KR960010295B1/en not_active IP Right Cessation
- 1994-09-27 EP EP94115201A patent/EP0645534B1/en not_active Expired - Lifetime
- 1994-09-27 DE DE69408760T patent/DE69408760T2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
EP0645534A1 (en) | 1995-03-29 |
JPH0797967A (en) | 1995-04-11 |
DE69408760T2 (en) | 1998-06-25 |
KR960010295B1 (en) | 1996-07-27 |
DE69408760D1 (en) | 1998-04-09 |
KR950008932A (en) | 1995-04-19 |
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