Gurgaon-based JBM Group had unveiled its ambitious bus manufacturing plans at the Auto Expo 2014 and showcased its Citylife bus packed with advanced features for safer travel among commuters. Auto Tech Review recently overviewed the company’s bus manufacturing set-up to understand what makes the Citylife bus different and what prospects drove the company to spend Rs 500 cr on the bus project.
Indian bus market currently accounts for around 40,000 units annually (7.5 tonne and above). After falling 25 % in FY18, the bus market registered growth of 10 % in FY19. Where on one hand, home-grown players like Tata Motors, Ashok Leyland and Eicher continue to dominate the commuter bus market, foreign players like Volvo and Mercedes-Benz continue to dominate the premium bus market. Getting a foothold in this market hasn’t been easy for the JBM Group. Nonetheless, the company continues to invest in building engineering and production capabilities.
The JBM Group’s bus business is carried out of two manufacturing sites. The Ballabhgarh facility in Haryana undertakes bus structuring work, while the entire assembly operations of the bus peripherals are carried out at its Kosi Kalan plant in Uttar Pradesh. The two plants combine to produce 150 units monthly.
The Citylife bus was designed by the company’s R&D team based in Ballabhgarh. The 12 m long 16.2 tonne Citylife bus has been developed as per European standards for frontal collision, roll over and side impact. The uni-floor system based on its ultra-low floor design has an entry height of 340 mm for commuter comfort and safety, claims the company.
The complete vehicle design including drive ergonomics, passenger movement and seating has been fully modelled using 3D computer aided design (CAD) and computer aided engineering (CAE) systems. With state-of-the-art validation and testing along with AC airflow, the engine room analysis is carried out on Computational Fluid Dynamics (CFD) at the company’s Ballabhgarh plant. In case of any new order, vehicle integration takes place at the R&D centre, where the portfolio is matched with the customer requirements, while adhering to AIS standards.
Stainless steel tubes are moulded into the fixtures developed by JBM engineers to manufacture sides, front, back as well as flooring of the buses. The structural sides are then clubbed together and tagged to develop monocoque bus structure that is treated with chemical coatings internally and externally for corrosion resistance. Monocoque structures perform better in the long-term in comparison to the body-on-chassis structures, which has multiple pressure points, the company said. These structures are subsequently tested for structural alignment using ultrasonic coordinate measuring machines and also for rigidity and torsion stiffness. The structure is allowed for not more than 5 mm tolerance to maintain the structural accuracy, the company claimed. The structure is then painted and transferred to the Kosi Kalan plant for further operations.
KOSI KALAN PLANT
The Kosi plant, which is divided into four lines working in S-shape, undertakes 26 operations. The main lines are closely supported by sub-assemblies located adjacent to main assembly lines. Various kits for buses – tyres & wheels, CNG cylinders, axle assemblies are worked up in the sub-assembly area for smoother operations in the main line.
Every vehicle that enters the main assembly line is attached with vehicle travel card (VTC) that is followed till the time a ready vehicle goes out for final inspection before delivery. Line one undertakes critical operations such as wood floor installation, insulation and roof build up to make it ready for the engine and peripherals deployment. The Citylife bus is available in two six cylinder engines, powered by diesel and CNG (BS IV compliant) – both of which are sourced from Cummins. The CNG version gets the Cummins ISB 5.9 G 230 engine that generates 230 hp at 2,800 rpm and max torque of 678 Nm at 1,600 RPM. Citylife’s diesel version is also available in two options – a Cummins ISBe 5.9 230 40 engine that generates 230 hp at 2,500 rpm and 850 Nm of torque at 1,300-1,800 rpm and also the Cummins 6ISBe 300B 40 engine that puts out 300 hp at 2,500 rpm and 1,100 Nm of torque at 1,200-1,700 rpm.
After the engine deployment, the structure is equipped with air-conditioners sourced from suppliers like Valeo Motherson Thermal Commercial Vehicles India Ltd and Eberspacher for a range for 12-18 kW, depending on the order requirements and area of application like city travel or tarmac. Critical operations like CNG cylinder installation is done right after the engine and AC installation to prepare the system for the next stage. Four CNG cylinders of 180 l each are stacked and carried on the rack for easy inspection and interchangeability and also reduces the number of joints for improved reliability. The CNG system is designed for easy inspection of joints & valves from the side of the bus and is equipped with auto shut-off valves for added safety, the company stated.
This is closely followed by internal lights and panel installation in the structure. At the following station, the bus is engineered with front and rear suspension, where the CNG version is loaded with air suspension, while the diesel version of Citylife gets electronically controlled air suspension. Independent front suspension with two air bellows and telescopic shock absorbers are installed at the front suspension, whereas inverted portal axle with air suspension, four air bellows and telescopic shock absorbers along with stabiliser bar is deployed at the rear end of the structure, following which the line one operations end. The inverted portal axle with higher rear axle ratio in Citylife results in higher wheel torque, the company said.
JBM opted for high pressure laminated (HPL) sheets for developing the bus exterior to keep the structure light and robust. Internal cladding is installed in the very first step of the second phase line, followed by brake system installation in which Citylife gets all wheel disc-brakes with dual circuit full air system and anti-lock brake system as standard in both CNG and diesel variants. In the next workstation, the engine is mated to automatic transmission with inbuilt retarder, wherein the latter provides additional speed shed during down slope of flyovers and gradients, the company said. Subsequently in the next three steps, the bus is fitted with all the exterior panels and floor lining along with seating design as per the customer requirement, following which the structure turns towards line three.
Citylife has been designed in a way that the entire engine along with the transmission can be evacuated from the bus structure by unscrewing just four bolts to maintain serviceability of the vehicle. The vehicle gets ample space on each of the rear-end side panels for easy access of radiator, coolant and fire detection system. Rear engine buses in tropical climate like India often experience heating up. To address this issue, the Citylife has been fitted with polyurethane foam insulation (PUF) mesh grille at the rear end side panels, which helps reduce engine temperature as well as its peripherals during tough operations. The Citylife also gets cantilever seats as standard that are mounted on the bus side panels rather than the floor for passenger safety and quick cleaning operations.
THRUST ON SAFETY
The vehicle has also been installed with variety of safety features like denial of bus moving forward to remove any kind of driver negligence. The doors system has been interlocked with bus transmission that tends to deny bus moving forward in case the doors are left open. The bus also won’t move forward in case fuel fill-up valves are left open at CNG stations or CNG leak is detected by sensors installed at the back and on the top of the vehicle.
The line three operations start with glasses and window panel deployment on the structure, followed by driver and passenger doors installation along with side flaps. The pneumatically operable doors can also be accessed manually from outside the bus in case of any emergency. The Citylife gets electrical systems and internal trimming like dashboard in the two following workstations. Critical safety alerts like door open, CNG leak alerts are also available on the dashboard for quick reference. Mirrors and display boards are installed in the next few steps, following which installation of front windscreen marks the end of operations on line three. At this gate, the vehicle undergoes testing to complete any kind of pending work that got missed during operations across previous three lines.
Workstations at line four manage the end-of-line phase, where engine & transmission oils, CNG and AC gas are topped up in the bus. It is at this stage that the vehicle gets to life and is subjected to a pollution test, followed by a headlight levelling test. Before the vehicle undergoes a wheel alignment test, the bus is subjected to a roller brake test at the facility. The ready structure is then sent-off for the first road test of up to five km to check for any shortcomings or leakages, before it is sent for the shower test. As part of the process, buses need to go through various tests on surfaces, tracks and inclines before it undergoes a shower test.
After the clearance from quality inspectors, the vehicle is subjected to a shower test, where each bus is subjected to high pressure water nozzles operating at pressure of up to two bars for 20 min, as per AIS standards. Following a successful completion of the shower test, a final report is developed inside the plant before it is once again sent-off for a five-km road test. Once approved, the bus is ready for final delivery.
JBM Auto has tied up with Italian bus maker BredaMenarinbus (BMB) as the technology partner for the Citylife bus project. It has supplied 50 units to the Noida Metro Rail Corporation and is on the verge of completing an order of 200 units that will be deployed in Gurugram. These buses are equipped with features like Intelligent Transport Management System (ITMS), automatic bus vehicle location system, CCTV cameras, public address system & stop request buttons, smart card ticketing system, real time Passenger Information System (PIS), and wheel chair ramp, to name a few.
The company also launched its 100 % pure electric bus ‘Ecolife’ developed in association with Polish bus maker Solaris at the 2018 Auto Expo in Delhi. The company has drawn up plans to invest close to Rs 300 cr in a phase-wise manner for project engineering, design & development, manufacturing, supply chain development, among other focus areas in the electric mobility project. Ecolife is powered by fast-charging lithium batteries, and can run up to 200 km a day for city bus operations, with the option of running on plug-in charging.
TEXT: Anirudh Raheja
PHOTO: Bharat Bhushan Upadhyay/ JBM