Fire trucks are mainly used for emergency rescue of various fires and various disasters and accidents. There are many varieties and small batches. The technical design of the fire truck mainly selects the appropriate chassis according to the functions and requirements of different fire trucks, and focuses on system design in terms of power matching and axle load checking. The special device is the heart of the fire truck, which can be selected from various existing assemblies and parts, and can also be innovatively designed according to needs.
The general fire truck design mainly includes the following specific contents:
Determine the main performance indicators of fire trucks
The main performance indicators of fire trucks mainly refer to special performance indicators. The special performance indicators are mainly determined according to the special functions of the fire truck. Generally, the special performance indicators are determined through the analysis of technical data of existing products, market research, customer needs, potential needs and other aspects. like:
(1) Tank type fire extinguishing truck: The special performance indicators generally include fire pump flow, fire monitor range, liquid tank capacity, etc. In addition, the type of fire extinguishing agent and whether it has a mixing system are also considerations.
(2) Rescue anti-vehicle: main rescue functions and technical indicators, such as crane lifting weight, traction capacity, generator function, lighting illumination, etc.
Other special performance indicators of fire fighting vehicles are also based on their special functional characteristics to determine reasonable performance indicators.
The basic performance indicators of fire trucks (including vehicle power, fuel economy, braking, handling stability, passability, etc.) are generally determined by the performance of the chassis.
In some cases, the general performance indicators of the chassis can be sacrificed to meet the specific performance indicators.
Choose the right chassis
Under normal circumstances, fire trucks use the chassis of the car to install special fire-fighting devices to achieve special functions and complete special emergency rescue and disaster relief tasks such as fire fighting and rescue.
The second-class chassis is mostly used in fire trucks, and of course other chassis are also used.
The main indicators generally considered when choosing a chassis are:
1) Engine power
2) The total mass and curb mass of the chassis (including the axle load index of each axle)
3) Passability of the chassis (including approach angle, departure angle, pass angle, minimum height from bottom, turning radius, etc.)
4) Whether the speed ratio and output torque of the power take-off can be operated continuously for a long time
According to the existing fire truck standards, the following performance indicators should also be checked:
In the static state, the water temperature, oil temperature, power take-off temperature, etc. of the engine after continuous operation near the full load state.
With the advancement of technology, some special chassis for fire trucks have appeared, and some general chassis manufacturers have introduced special chassis for fire trucks.
General arrangement drawing
The fire truck is actually to install various special fire-fighting devices on the chassis. When drawing the general layout drawing, the specific position and relative size of each special device should be drawn on the layout drawing according to the functional requirements, reflecting the arrangement form of the power take-off transmission device.
Fire trucks generally give priority to the space utilization of the skirt, and can shift the components on the chassis that affect the layout of functional parts, such as fuel tanks, batteries, air storage tanks, etc., and sometimes even consider the displacement of air filters and mufflers. However, with the increasing emission requirements, the displacement of some components (such as the muffler) may affect the emission performance of the car, and chassis manufacturers will prohibit corresponding changes. The displacement of the air filter may also affect the normal operation and power performance of the engine. play. In addition, with the application of automation and intelligent technology on automobile chassis, irregular shifting operations will affect the safe operation of the chassis and the generation of fault codes. Therefore, the above modifications must be performed in accordance with the requirements of the chassis modification manual.
The general layout should consider the conformity of the standard.
Calculation of performance parameters
After the general layout plan is determined, the corresponding performance parameters need to be calculated:
(1) According to the overall layout plan, the impact on the original performance of the chassis after modification, such as whether there is any impact on the approach angle, departure angle, and passing angle, the rationality of the axle load arrangement, etc.
(2) The ability to guarantee the performance of special devices, such as power matching, checking of performance indicators of each device, long-term continuous operation, etc.
Through the above calculations, the overall layout plan can be adjusted appropriately.
Assembly and component design
The design of each assembly and parts shall be carried out under the framework of the general layout plan, and shall be checked on the general layout drawing after the design.
This work is the main part of fire truck design, and it is also the focus of in-depth research and innovative design. It should be noted that it can generally be improved and applied on the basis of existing assemblies and components, and it also needs to meet the requirements of various standards and regulations.
There are many manufacturers and suppliers of fire-fighting assemblies and parts. Usually, suitable assemblies and parts can be selected, but attention should be paid to reasonable matching. At the same time, motion checks must be performed on moving parts to make them work in harmony. , to perform its proper function.
Post time: Mar-13-2023