JPS643052U

JPS643052U -

Info

Publication number: JPS643052U
Application number: JP9782587U
Authority: JP
Priority date: 1987-06-25
Filing date: 1987-06-25
Publication date: 1989-01-10

Description

[Brief explanation of the drawing]

第１図は本考案のクレーム対応図、第２図は本
考案の一実施例を示すブロツク図、第３図はこの
実施例の制御内容を示す流れ図である。第４図Ａ
と第４図Ｂは機関回転数を一定とした場合におい
て機関負荷を相違させた実験結果で、それぞれ低
負荷域と中高負荷域での騒音レベルとＨＣ及びＮ
Ｏｘ排出量に対する噴射期間比の影響を示す特性
図である。第５図は従来例のポンプ断面図、第６
図Ａと第６図Ｂはそれぞれ通常噴射とパイロツト
噴射時の燃料噴射特性を示す説明図、第７図はフ
エイスカムのカム速度特性図である。１…ポンプハウジング、３…プランジヤポンプ
、５…ポンプ室、７…プランジヤ、９…フエイス
カム、１１…ローラ、１２…プランジヤ室、１３
…熱料戻し通路、１４…電磁弁、１６…電磁弁駆
動回路、２２…機関回転数検出手段、２３…機関
負荷検出手段、２４…負荷時の全噴射期間算出手
段、２５…無負荷時の全噴射期間算出手段、２６
…領域判定手段、２７…パイロツト噴射の噴射期
間算出手段、２８…主噴射の噴射期間算出手段、
２９…駆動パルス発生手段、４１…回転数センサ
、４２…上死点センサ、４３…アクセル開度セン
サ、４４…コントロールユニツト、４６…メモリ
、４７…開閉時期センサ。 FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a flowchart showing the control contents of this embodiment. Figure 4A
Figure 4B shows the results of experiments with different engine loads when the engine speed is constant, and the noise level and HC and N in the low load range and medium-high load range, respectively.
FIG. 3 is a characteristic diagram showing the influence of the injection period ratio on the amount of Ox discharged. Figure 5 is a sectional view of a conventional pump;
Figures A and 6B are explanatory diagrams showing fuel injection characteristics during normal injection and pilot injection, respectively, and Figure 7 is a cam speed characteristic diagram of the face cam. DESCRIPTION OF SYMBOLS 1... Pump housing, 3... Plunger pump, 5... Pump chamber, 7... Plunger, 9... Face cam, 11... Roller, 12... Plunger chamber, 13
...heat return passage, 14...electromagnetic valve, 16...electromagnetic valve drive circuit, 22...engine rotation speed detection means, 23...engine load detection means, 24...total injection period calculation means at load, 25...at no load Total injection period calculation means, 26
...Area determination means, 27.. Injection period calculation means for pilot injection, 28.. Injection period calculation means for main injection,
29... Drive pulse generating means, 41... Rotation speed sensor, 42... Top dead center sensor, 43... Accelerator opening sensor, 44... Control unit, 46... Memory, 47... Opening/closing timing sensor.

Claims

[Scope of utility model registration request]

A low-pressure feed pump and a high-pressure plunger pump that rotate in synchronization with engine rotation are provided, and an electromagnetic pump that opens and closes using a drive pulse is installed in the fuel return passage that communicates the low-pressure pump chamber of the feed pump formed in the pump housing with the high-pressure plunger chamber of the plunger pump. The fuel injection pump is equipped with a valve, and the fuel injection start timing and injection period are variably controlled by the opening and closing of this solenoid valve.The fuel injection pump is divided into two injections, and the pilot injection is performed prior to the main injection. What is claimed is: 1. A fuel injection control device for a diesel engine, characterized in that the injection period of the pilot injection is set to 1/2 of the total injection period under no-load conditions.