柴油发动机飞车事故如何处理 How to deal with diesel engine runaway accidents

柴油发电机组额定容量主要在10KVA至2000KVA这个范围。更小的机组通常用汽油机，更大的机组通常用重油机组、燃气机组以及燃煤机组。

一般柴油发电机的启动容量仅仅为其额定容量的20-30%，也就是说，100KW的柴油发电机能够启动的电机最大容量为20-30KW。这是因为柴油发电机的油门不能在大电机启动时快速打开到正确的位置，所以会造成柴油发电机的转速下降，也就是频率下降，甚至柴油机被憋死停机。而电机启动电流为额定电流的6-10倍，在如此大的电流冲击下，发电机组的机端电压将下降，当然发电机的励磁保护会马上反应并增大励磁电流，但这有一个过程，所以在电机启动时，柴油发电机会出现电压降低的现象。电机越大，启动电流越大，电压降低越多，当55KW电机在100KW发电机上启动时，会造成很大的电压降。由于接触器合闸吸合电压就是其回路电压，发电机电压大幅度下降，其结果将造成由于吸合电压过低，接触器失压而跳闸。

在工程机械维修实践中，常常遇到柴油发动机因高压油泵调速齿条或齿圈卡在最大供油位置，或因各种原因导致调速器失去调速特性，及气缸中进入其它燃料，特别在同时起动发动机或换档、去除负荷等时，发动机出现飞车故障。

飞车后，若采取紧急措施，如:堵塞进气管，将减压手柄拉到减压位置，使用排气制动，迅速松开各缸高压油管停止供油等，可制止飞车事故。

若飞车后采取措施不及时，发动机长时间超速运转，将可能发生连杆螺栓拉断、打破机体等恶性事故，也可能使调速器飞锤或钢球甩脱、碰撞或打烂调速器壳体，喷油泵凸轮轴转动受到限制，油泵不再供油，发动机自动熄火停转。

在调速器壳体被打烂的飞车故障中，除需按常规校正喷油泵及对发动机各运动部件的联接可靠性、配气机构杆件的弯曲变形进行校正外，还要重调供油正时。因为当飞锤用脱卡滞时，喷油泵凸轮轴被飞锤端强制停转，喷油泉停止供油，汽缸内不再爆发作功，但飞车后高速运转的发动机不能立刻停转，在巨大惯性作用下将继续运转一段时间，同时通过正时齿轮间

的传动带动喷油泵正时齿轮轴继续转动。这样，正时齿轮将对油泵驱动轴施加一驱动其继续旋转的冲击扭矩，因凸轮轴飞锤端转动受阻，联轴器胶木联接块可能被挤碎，喷油泵正时齿轮与齿轮轴间的联接键可能被剪断，而错离原装配位置。同时，作为铸件加工成的油泵凸轮轴，其直径大于作为细长杆件的油泵正时齿轮轴，当飞锤甩脱打烂调速器壳体油泵被强制停转时，正时齿轮轴在发动机继续高速旋转造成的巨大冲击扭矩作用下将产生扭曲变形，凸缘盘端转角滞后于正时齿轮端转角。所以在发生调速器打烂壳体的情况下，若是简单的修校好高压油泵就装车发动，常常失败。较彻底的处理办法是打开正时齿轮室盖，检查油泵正时齿轮轴是否滚键。若是，就拆下齿轮轴重新配键。若无滚键，就要检查齿轮轴的扭曲变形。先对正时记号，然后盘动发动机曲轴，盘至飞轮上一缸供油提前角刻线的要求角度，油泵装到机体上，联接进回油管，不装高压油管，联轴器凸缘盘定位螺钉不装。油泵排空气注满柴油后，盘动凸缘盘到一缸供油开始位置。此时查看定位螺钉孔与前凸缘盘上弧形槽相对位置，若相差角度太大无法靠联轴器处调整，此时就要重调油泵正时齿轮，即抽出油泵齿轮轴，在自由状态下按正常旋转方向转动齿轮轴，到联轴器驱动凸缘盘弧形孔中心位置正对中间凸缘盘固定螺孔位置，按此位置装上齿轮轴，拧紧凸缘盘固定螺钉，喷油泵供油正时即可恢复。同时应按相差齿数在相应的齿上重新打上正时标识，利于后来维修工作。

如发动机前端空间太小，只有吊出发动机才能打开正时齿轮室盖，而现场无起吊设备，又需进行现场急救时，可进行如下处理:把校正好的油泵按正常安装位置装复，接好低压油路，排空气注满油。打开一缸气门室盖，盘动曲轴同时查看一缸进排气门摇臂运动情况，到飞轮上一缸供油开始时刻。盘动联轴器从动盘到一缸出油阀紧座出油口油面波动，停止转动。

反向盘动从动凸缘盘，到中间凸缘盘固定螺钉正对驱动凸缘盘上弧形长孔中心位置，固定凸缘盘定位螺钉。在发动机体上正对正时齿轮轴处涂盖湿泥，用喷灯或氧炔焰加热正时齿轮轴，到能用开口扳手按喷油泵旋转方向在油泵端扳动从动凸缘盘，不可过加热。此时油泵转动，而正时齿轮端受发动机静止状态限制不能转动。到一缸出油阀紧座出油口油面明显波动为止，保持此位置不动待正时齿轮轴冷却。这样喷油泵与正时齿轮轴恢复到轴扭曲变形前对应位置。继续盘动曲轴一周，正时齿轮轴上第一次加热时火焰没有直接加热到的一面转向正外面，进行第二次加热，基本与第一次加热一致。冷却后轴上二对应表面受热残余内应力基本一致。轴不致发生明显挠曲变形，传动稳定性好。以上方法比较简单，可作现场救急之用。但因为加热火候不易控制，齿轮轴难免存在因残余应力不平衡引起的挠曲变形。条件许可情况下，更换正时齿轮轴效果最好。

注意事项：

1、用户必须熟读本说明书，严格按说明书的规定使用、维护、保养柴油机。

2、不得随意拆卸、调整喷油泵和喷油器。

3、严禁使用劣质或不清洁的柴油和机油。

4、严禁在缺机油情况下起动。

5、严禁超负荷工作等违章操作。

6、不得有杂物堵塞进风口。

7、严禁在未经固定或过度倾斜的情况下工作。

The rated capacity of diesel generator sets mainly ranges from 10KVA to 2000KVA. Smaller units typically use gasoline engines, while larger units typically use heavy oil units, gas units, and coal-fired units.

The starting capacity of a typical diesel generator is only 20-30% of its rated capacity, which means that a 100KW diesel generator can start a motor with a maximum capacity of 20-30KW. This is because the throttle of the diesel generator cannot be quickly opened to the correct position when the large motor starts, which can cause a decrease in the speed of the diesel generator, that is, a decrease in frequency, and even the diesel engine may be suffocated and shut down. The starting current of the motor is 6-10 times the rated current. Under such a large current surge, the terminal voltage of the generator set will decrease. Of course, the excitation protection of the generator will immediately respond and increase the excitation current. However, this is a process, so when the motor starts, the diesel generator will experience a voltage drop. The larger the motor, the greater the starting current and the greater the voltage drop. When a 55KW motor is started on a 100KW generator, it will cause a significant voltage drop. Due to the fact that the closing voltage of the contactor is its circuit voltage, the generator voltage drops significantly, resulting in the contactor tripping due to low closing voltage and loss of voltage.

In the practice of engineering machinery maintenance, it is often encountered that diesel engines experience runaway faults due to the high-pressure oil pump speed control rack or ring gear getting stuck at the maximum fuel supply position, or due to various reasons causing the speed controller to lose its speed control characteristics, and other fuels entering the cylinder, especially when starting the engine or shifting gears, removing loads, etc. at the same time.

After flying, if emergency measures are taken, such as blocking the intake pipe, pulling the pressure reducing handle to the pressure reducing position, using the exhaust brake, quickly releasing the high-pressure oil pipes of each cylinder to stop fuel supply, etc., the flying accident can be stopped.

If measures are not taken in a timely manner after speeding, the engine may run at an excessive speed for a long time, which may lead to serious accidents such as connecting rod bolt breakage and engine body breakage. It may also cause the governor flying hammer or steel ball to detach, collide, or damage the governor housing. The rotation of the fuel injection pump camshaft is restricted, the fuel pump will no longer supply fuel, and the engine will automatically shut down and stop running.

In the case of a runaway fault where the governor housing is damaged, in addition to correcting the fuel injection pump and the reliability of the connection of various moving parts of the engine, as well as correcting the bending deformation of the valve rod, it is also necessary to readjust the fuel supply timing. Because when the flying hammer is disengaged, the camshaft of the fuel injection pump is forced to stop rotating by the flying hammer end, the fuel injection spring stops supplying fuel, and the cylinder no longer produces power. However, the engine that runs at high speed after flying cannot stop immediately, and will continue to operate for a period of time under the action of huge inertia, while passing through the timing gears

The transmission drives the fuel injection pump timing gear shaft to continue rotating. In this way, the timing gear will apply an impact torque to drive the oil pump drive shaft to continue rotating. Due to the obstruction of the camshaft flying hammer end rotation, the coupling rubber joint block may be crushed, and the connecting key between the timing gear of the fuel injection pump and the gear shaft may be cut off, deviating from the original matching position. At the same time, as a cast oil pump camshaft, its diameter is larger than that of the oil pump timing gear shaft as a slender rod. When the flying hammer is thrown off and breaks the governor housing, the oil pump is forced to stop rotating. Under the huge impact torque caused by the continued high-speed rotation of the engine, the timing gear shaft will undergo twisting deformation, and the flange end angle will lag behind the timing gear end angle. So in the case of the governor breaking the shell, if the high-pressure oil pump is simply repaired and started before installation, it often fails. A more thorough solution is to open the timing gear chamber cover and check if the timing gear shaft of the oil pump has rolled keys. If so, remove the gear shaft and reassemble the key. If there is no rolling key, check the distortion and deformation of the gear shaft. First, mark the timing, then turn the engine crankshaft to the required angle of the fuel supply advance angle mark on the flywheel. Install the oil pump onto the engine body, connect the inlet and return oil pipes, and do not install the high-pressure oil pipe. Do not install the coupling flange plate positioning screw. After the oil pump exhausts air and fills diesel, rotate the flange plate to the starting position of the first cylinder fuel supply. At this point, check the relative position between the positioning screw hole and the arc-shaped groove on the front flange plate. If the angle difference is too large to adjust by the coupling, the oil pump timing gear needs to be readjusted. That is, extract the oil pump gear shaft and rotate it in the normal rotation direction in a free state until the center of the arc-shaped hole on the driving flange plate of the coupling is aligned with the fixed screw hole position on the middle flange plate. Install the gear shaft at this position, tighten the fixing screw on the flange plate, and the fuel injection pump supply timing can be restored. At the same time, timing markings should be re applied to the corresponding teeth according to the number of teeth that differ, which will facilitate subsequent maintenance work.

If the front space of the engine is too small and the timing gear chamber cover can only be opened by lifting out the engine, and there is no lifting equipment on site, and on-site first aid is needed, the following measures can be taken: reinstall the calibrated oil pump in its normal installation position, connect the low-pressure oil circuit, and exhaust air to fill the oil. Open the valve cover of cylinder one, rotate the crankshaft, and check the movement of the rocker arms of the intake and exhaust valves of cylinder one until the start of fuel supply to the flywheel of cylinder one. Drive the coupling from the driven disc to the tight seat of the first cylinder oil outlet valve, causing fluctuations in the oil level at the outlet and stopping the rotation.

Reverse the driven flange plate until the fixing screw of the middle flange plate is aligned with the center position of the arc-shaped long hole on the driving flange plate, and fix the positioning screw of the flange plate. Apply wet mud on the engine body facing the timing gear shaft, heat the timing gear shaft with a spray gun or oxyacetylene flame until it can be turned on the driven flange plate at the oil pump end with an open-end wrench in the direction of the fuel injection pump rotation, without overheating. At this point, the oil pump is rotating, while the timing gear end is restricted from rotating due to the engine's stationary state. Until the oil level at the outlet of the tight seat of the first cylinder oil outlet valve fluctuates significantly, keep this position still and wait for the timing gear shaft to cool down. In this way, the fuel injection pump and timing gear shaft are restored to their corresponding positions before the shaft twisted and deformed. Continue to rotate the crankshaft once, and the side of the timing gear shaft that was not directly heated by the flame during the first heating will turn towards the outside for the second heating, which is basically the same as the first heating. The residual internal stresses on the two corresponding surfaces of the cooled rear axle are basically the same. The shaft does not undergo significant bending deformation and has good transmission stability. The above methods are relatively simple and can be used for on-site emergency rescue. However, due to the difficulty in controlling the heating temperature, the gear shaft is inevitably subject to bending deformation caused by residual stress imbalance. When conditions permit, replacing the timing gear shaft has the best effect.

matters needing attention:

1. Users must read this manual thoroughly and strictly follow the instructions to use, maintain, and upkeep the diesel engine.

2. Do not disassemble or adjust the fuel injection pump and injector at will.

3. It is strictly prohibited to use inferior or unclean diesel and engine oil.

4. It is strictly prohibited to start in the absence of engine oil.

5. Overloading and other illegal operations are strictly prohibited.

6. No debris should be stuffed into the air vent.

7. It is strictly prohibited to work without fixing or excessive tilting.