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LPG Tricycle


Environment Protection Research Center (EPRC)

Waste collection and transportation are important steps in the integrated management of municipal solid wastes [1]. In fact there are two options: collection-direct transportation and through transfer stations to the landfill.  In the conditions of not well-developed infrastructure, the movement of garbage-pressed dumpers in urban areas with the option of waste collection-direct transportation to the landfill has caused significant difficulty for the city traffic. On the other hand, due to speed slowing-down and often stopping, garbage-pressed dumpers make air pollution rise. Intermediate station option could overcome the above-mentioned weaknesses and this option is now applied in Danang City. Diagram of the system for collection and transportation of garbage in Danang is shown in Figure 1.

  1. Waste bin in the street
  2. Worker transports wastes on tricycle cart to an intermediate station
  3. Pressing garbage at an intermediate station
  4. Big truck transports wastes from an intermediate station to the landfill
  5. Wastes dumped at the landfill

(Figure 1. Waste collection and transportation in Danang City)

The diagram of the solid waste collection and transportation in Danang City shows many advantages, firstly limiting garbage pressed vehicles running in the city, thereby reducing the level of air pollution emission. On the other hand, the diagram allows the use of large trucks to transport wastes from the transfer stations to landfill instead of using small-sized garbage pressed vehicles. This way is more economical. The only weakness of the above diagram is to use tricycle-cart with the manpower to carry waste bins to the transfer stations [4]. This job requires a lot of manpower of the workers and creates an image not suitable for a modern and civilized city.
To improve the system for collecting and transporting solid wastes of Danang City, this paper suggests a small garbage tricycle operated by the engine instead of manpower. This kind of garbage tricycle reduces using of manpower and on the other hand increases the efficiency of waste collection and transportation, contributing to air environment protection because the tricycles use engines running with clean fuel LPG.

2. Requirements ofgarbage vehicles
 New garbage vehicle must first use engines instead of manpower. On the other hand it must run smoothly with less noise and less environmental pollution. With these requirements, garbage three-wheel motorcycle carts run by LPG are suitable [5]. Indeed, when replace the vehicle running on petrol to LPG, the level of pollution emissions can be reduced up to 80% [2], [3]. The conversion of the fuel system is made easily thanks to DATECHCO-GA5 Kit available (Figure 2) [6].
Garbage vehicle must have power equivalent to current carts. They should accommodate a waste bin of 660 liters (324kg) or two waste bins of 240 liters (120kg). The three-wheel motorcycle carts should have a small rotation radius to be able to operate in the condition of narrow lanes. The cost of the vehicle should be low. With this request, the option for upgrading three-wheel motorcycles from the two-wheel motorcycles, taking advantage of available parts-clusters is the most optimal.

                        a.                                         b.                                                 c.
 Figure 3: Types of upgrading three-wheel motorcycles from the two-wheel motorcycles

3. The design
The usual option of upgrading two-wheeled motorcycle into three-wheeled motorcycle is presented in Figure 3a, c. Most simple option is a pulled cart (Figure 3a) in which it is needed just to install a two-direction swivel into the saddle (Figure 3b) to pulltrailers. However this option makes the vehicle longer not suitable with requirements for garbage vehicles running in the lanes. The second option is to cut the tail of the motorcycle and directly weld the trailer to the motorcycle frame (Figure 3c) and transmission-posted. This option can shorten the body of the vehicle, but makes it high, difficult to get the waste bins out and into the trailer.
In this work we design low-floor vehicles in combination with chain transmission and reasonable suspension lay-out. The pictures of the drive and suspension are shown in Figure 4. The vehicle uses three-chain transmission. The first transmission is from the engine to the intermediate shaft. The remaining two sets of transmission from the intermediate shaft to the rear wheel. Differential structure is on the intermediate shaft (Figure 4a). The center of the rear wheel can shake around the center of rotation "trap" (Figure 4b).
To simplify the fabrication, we retain the previous frame of the two-wheeled motorcycle. The vehicle is cut off the tail as shown in Figure 5 and the frame is tightened directly to its frame by bolts. Figure 6 presents the overall drawings of the vehicle.
Thanks to the installation of DATECHCO-GA5 Kit, the vehicle can run on either fuel, LPG or petrol. LPG/Petrol three-wheel motorcycle carts for garbage transportation after fabrication is introduced in Figure 7. Floor is lower to create favorable conditions for putting the waste bins out and into the cart (Figure 8).
4. The features of three-wheel motorcycle carts running on LPG
 Comparing the torque and capacity of 100cc engine running on petrol and LPG with DATECHCO-GA5 Kit is presented in Figure 7a, b. The power of the engine running on LPG is maximized at 3.5 kW at 600 rpm while maximum capacity of the engine running on petrol reaches 4.43 kW at speed of 7500 rpm. This is consistent with the above mentioned calculations. Maximum power of the engine running on LPG can be adjusted higher or lower than 3.5 kW by calculating the gas flow supplied. In fact, when switching from petrol to gas without changing the compression ratio of the engine, engine power reduced by about 10%, which means the maximum capacity of 100cc engine running on gas, can reach 4kW. Torque curve of the engine running on LPG is steeper than of the engine running on petrol. The lines of transmission characteristics of the engine running on LPG congruent with the ones of the engine running on petrol. Thus the features of the motor in operation are not affected when changing the fuel. Actual road test shows that the features of accelerating, overtaking, uphilling of the three-wheel motorcycle carts running on LPG are satisfactory with usage requirement.
Figure 7c compares the useful fuel consumption rate of the engine running on petrol and LPG. At low speed and high speed, the fuel consumption rate running on LPG and petrol is approximately the same. At intermediate speeds, especially when engine speed of about 5000 rpm to 7000 rpm, the fuel consumption rate of LPG engine is only 50% of the rate of fuel consumption when running on petrol. In fact, when running on the road, motorcycles consume in average 01kg of LPG/100km or 02 liters of petrol/100km. With gas price of 12.000VND/kg and petrol price of 11.000d/liter, using LPG to run the motorcycle with DATECHCO-GA5 Kit, consumers save more than 40% of fuel costs.


On the basis of the above experimental results for the drag of the engine, we can draw a dynamics graph, the dynamics of the garbage trucks run on LPG.
Traction balancing Graph of motors designed to run on LPG is introduced in Figure 10. The results show three-wheel motorcycle dumpers can run at a top speed of 48.02 km / h in the gear III with the same transmission ratio from the engine to the wheels as of two-wheel motorcycles. Acceleration characteristics of the three-wheel motorcycle dumpers are presented in Figure 11. From this graph it is shown that maximum speed v4max = 46.92 [km / h] (j = 0) in the fourth gear; and in the third gear - v3max = 48.02 [km / h]. Testing of riding three-wheel motorcycle dumpers on the road showed ​​that the maximum speed at full load is 40 km / h. To fully evaluate the effectiveness of transmission from the engine to the wheels, we need to conduct testing on engine test bed.
The calculated economic and other technical features of the garbage truck showed its smallest rate of fuel consumption is Qnl3 (min) = 1.008 [kg/100km] third gear with speed v = 38.82[km/h]. The biggest drag coefficient it can overcome is D1max = 0.1 corresponding to the largest road slope angle of Amax = 4.874 [degrees] at full load. When reducing the load by 50%, i.e. carrying only 150 kg the three-wheel motorcycle cart for garbagetransportation can pass slope D1max (50%) = 0.142 or 7.30 [degrees].So this vehicle is designed to achieve good economic and technical indicators when running in the inner city. Without loading, the vehicle can go on a slope of 0.242 or 13.14 [degrees] and the maximum speed can be reached at the fourth gear with Vmax = 55 [km/h], this helps environment workers go home fast at night with nearly nobody on the street.

When using large wheels as shown in Figure 8, the steering wheel is a bit heavy, especially when going on ramps. To overcome this drawback, we use the small front wheel (wheel of Chaly or Vespa motorcycles). Figure 12 introduces dumpers with small front wheel environment.
5. Conclusion
The above results allow us to draw the following conclusions:

  1. Using small garbage vehiclerunningon LPG will help URENCO increase the capacity of waste collecting and transporting, increase productivity, and reduce pollution in the city. On the other hand, using this vehicle for garbage transporting also enhances the landscape of the city, suitable to a modern and civilized city.
  2. The option of reforming motorcycles into three-wheel motorcycle carts for garbage transportation simplifies fabrication, taking advantage of the detailed parts of the old motorcycles, reducing production cost. Therefore, this method is suitable for small mass production.
  3. The designed vehicle for garbage transportation can run on dual fuel, or petrol, or LPG with DATECHCO-GA5 Kit. The features of running this engine have been verified by the Vietnam Registration – Control Agency. The specifications of the engine are appropriate with the traction load requirements of motorcycles on the road.
  4. Garbage vehicles with 100cc engine running on LPG with a capacity of 4.70 kW can reach a maximum speed of 48km/h, therefore LPG engine power meets the requirements of traction load of the vehicle. DATECHCO-GA5 Kit allows increasing engine power to limited engine power running on petrol when necessary.
  5. The garbage vehicle is designed to two small waste bins (240 liters) or one large bin (660 liters). Low floor height makes it easier to put the waste bins in the cart. The vehicle is designed nicely suitable with the urban landscape.

 The specifications of the three-wheel motorcycle carts are designed as follows:

No Specifications Value
1 Dimensions 2730 x 1239 x 1179
2 Basic Length (mm) 1720
3 Basic width (mm) 1020
4 Total weight(kg) 595
5 Rotation radius (mm) 2050
6 Rotation Corridor (mm) 1176
7 Maximumpower of the engine when running on petrol/LPG (Nm)  4.70/3.50
8 Maximumtorque of the engine when running on petrol/LPG 6.70/5.99
9 Primarytransmission ratio 4.058
10 Gear transmissionratio 2.833; 1.705; 1.238; 0.958
11 Maximum speedwhen running on petrol/LPG (km/h)

1. Bui Van Ga, Tran Van Nam: Solid Waste Treatment.
    Journal of Da NangScience and Development, No. 94, pp. 25-28, 2003
2. Bui Van Ga: Motorcycle running on dual fuel LPG / petrol.
     VietnamRegistration-Control, 10-2003, pp. 9-12
3. Bui Van Ga: Clean Motorcycles.
    Journal of Communications and Transportation 1+2-2005, pp. 75-77
4. Bui Van Ga, Nguyen Quan: The garbage three-wheel motorcycle cart.
    Danang Science and Development, 111-2005, pp. 14-17
5. BUI VAN GA: Combustion of LPG-Air Lean Mixture and its Application on Motorcycle Engines. Paper 043, International Conference on Automotive Technology for Vietnam, ICAT 2005. Hanoi, October 22-24, 2005.
6. Bui Van Ga, Tran Dien: Comparing characteristics of the 100cc engine running on     petrol and LPG with DATECHCO-GA5 Kit.
   Journal of Communications and Transport, No 7, pp. 15-17, 2006

 (English Translation: RP)