(22 Mar 2014, 10:12 pm)Davey Bowyer wrote Basically, we need a double deck vehicle manufacturer that will come up with a vehicle and chassis combination that will provide for routes where a heavyweight single deck such as the B8RLE hasn't got the capacity but the investment of a coach couldn't be justified due to financial and operational reasons (cascading vehicles). Ideally, we need a low floor double deck vehicle that:

- Meets Euro legislation
- Has at least a 9 litre engine with 270bhp or more
- Has a gear box with tall gearing ratios for constant high speeds
- Is double deck and low floor
- Is priced at around 200k mark or less
- Will last 7 years on a demanding route (X15 or X18)
- Will last a further 7 to 8 years on slightly less demanding routes (X14 or X20) whilst acting as a backup for previous demanding route (X18) with the very final 2 years before 15 year life span coming to an end backing up on routes such as 35, X14, X20, X21 and X22

(22 Mar 2014, 10:39 pm)aureolin wrote Can I ask the fascination about 9 litre engines? You can produce the same horsepower (and more) on smaller engine capacities than than.

(22 Mar 2014, 10:42 pm)Kuyoyo wrote Indeed, reading articles will show that the upcoming Euro6 B5TL will produce 240bhp, which is about what most B9TLs produce (a small number of the Go North East examples have more powerful engines). Compare that to Scania, it ranks 10bhp above Stagecoach's preferred engine choice on the Scanias, the 230bhp (K230 or N230).

(23 Mar 2014, 12:32 am)Andreos Constantopolous wrote A quick comparison of current Euro6 engines from Volvo http://www.volvobuses.com/bus/na/en-us/_layouts/CWP.Internet.VolvoCom/NewsItem.aspx?News.ItemId=130637&News.Language=en-gb

D5
• 240 hp 900 Nm (also available in biodiesel version)

D8
Three models:
• 280 hp 1050 Nm
• 320 hp 1200 Nm (also available in biodiesel version)
• 350 hp 1400 Nm

D11
Three models:
• 380 hp 1800 Nm
• 430 hp 2050 Nm
• 460 hp 2200 Nm

The resulting economic analysis suggested that procurement of a hybrid bus in lieu of a B12 will deliver a negative economic outcome, with a projected loss of $113,950 (net present value basis) over the life of the vehicle, and a benefit-cost ratio of 0.84.
Compared with a bus fitted with contemporary B7 technology, the economic outcomes are more negative than for the B12, with a projected loss of $313,920 over the life of the vehicle (net present value basis), and a benefit-cost ratio of 0.10.
A sensitivity analysis revealed that the quantum of the above losses would be partly reduced in the face of substantial rises in diesel fuel prices, but the overall economic outcomes would likely remain negative under even more aggressive fuel price rise scenarios.
While the hybrid technology (as trialled) delivered a fuel efficiency benefit of around 15% relative to conventional B12 technologies, this benefit was not sufficient to offset the higher capital cost and ongoing maintenance costs of the hybrid bus. It is estimated that an 88% reduction in the capital cost of the hybrid bus technology would be required to support a break-even investment when compared with a traditional diesel bus operating 70,000 km p.a. over 25 years.
In the case of the more contemporary B7 bus technologies, the hybrid technology (as trialled) was less fuel efficient. This factor, coupled with the higher capital and maintenance costs over a typical bus life, suggests that the B7 currently delivers superior operational, environmental and economic outcomes when compared with hybrid bus technologies.

(23 Mar 2014, 5:56 am)G-CPTN wrote From:-
It's quite easy to see that the larger capacity engines offer higher torques (and, therefore, better 'pulling power'). Higher horsepower will result at the same engine revolutions (power is torque times revolutions).

Two different approaches to the same topic:-

http://www.largiader.com/articles/torque.html

http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

An engine with higher torque is capable of pulling longer gearing ratios, thereby giving the same roadspeed at lower engine revolutions.

The work done is the same (for equivalent roadspeed) but consumption will depend on the comparative economy of the engines at those revolutions.
The smaller capacity engine at higher engine revolutions might well be using more fuel to achieve this - but this will depend on the engine management system.
It is, perhaps, obvious that the components within the smaller capacity engine will 'run further' to achieve the same performance, and, therefore be expected to wear out sooner.

Conversely, if the gearing ratios are the same the larger capacity engine will probably use more fuel (again, depending on the engine management system). Throttle opening position will determine how much fuel is delivered (and how much performance is delivered) so judicious use of the pedal will reduce fuel consumption. A sophisticated 'drive by wire' control could optimise this.

(25 Mar 2014, 9:57 pm)Andreos Constantopolous wrote 240 bhp is quite frankly shocking.
There are some cars with even more bhp than the bus engine!

(11 Oct 2014, 7:24 pm)Dan wrote Video: New Bus Technology Spots Available Seats Upstairs
http://londonist.com/2014/10/video-new-bus-technology-spots-available-seats-upstairs.php

Not local, but perhaps something which could come to the North East in the future, should the trial be successful in London...

(11 Oct 2014, 7:24 pm)Dan wrote Video: New Bus Technology Spots Available Seats Upstairs
http://londonist.com/2014/10/video-new-bus-technology-spots-available-seats-upstairs.php

Not local, but perhaps something which could come to the North East in the future, should the trial be successful in London...

(11 Oct 2014, 7:24 pm)Dan wrote Video: New Bus Technology Spots Available Seats Upstairs
http://londonist.com/2014/10/video-new-bus-technology-spots-available-seats-upstairs.php

Not local, but perhaps something which could come to the North East in the future, should the trial be successful in London...

On a conventional hydraulically driven fan system, air is sucked from the outside of the bus through a charge air cooler with a hydraulic oil cooler alongside and then through a jacketed water filled radiator by a large fan driven by a hydraulic motor and controlled by a hydraulic control valve. AVID say this method traps debris within the system making it less effective. The debris becomes difficult to remove and the radiators are easy to damage. The system is also prone to hydraulic leaks.

With the AVID eFan micro hybrid system, air flows through a bank of high performance brushless DC electric fans, cooling a charge air cooler and a water radiator. There are usually six fans, four cooling the water system and two the charge air. Cooling the charge air cooler and the water radiator independently enables their temperatures to be more accurately controlled. The electric fans used are units specially designed for vehicle applications delivering 50% more airflow than the most efficient similarly sized units available commercially. They can be run in reverse, effectively as powerful blowers, to remove accumulated debris and keep the system running cleanly and efficiently. There is no hydraulic system so it can’t leak and doesn’t need cooling.
The system is controlled by an electronic controller connected to the vehicle’s CANbus system. It monitors the water temperature through a sensor in the radiator inlet and the charge air temperature through a sensor in the charge air cooler outlet. There are three functions available to the maintenance team on each system, a reversing switch that enables the fans to be run as blowers, a diagnostic connector port and a diagnostic lamp button.
A major difference between the hydraulic and electric systems is the energy required. When operating at full capacity, the eFan uses 3kW compared with a figure of around 20kW for a hydraulic system. On top of this, it only runs when needed and switches itself off when it isn’t. This ensures that engines operate at their optimum running temperature and also, because the fans do not operate when they are not needed in the early stages of a vehicle’s duty cycle, reduces the warm up time.
The absence of hydraulic fluid is a significant safety factor because, they claim, it is often a hydraulic problem that will start an engine bay fire or exacerbate one started in another way.
Another benefit from fitting an eFan is a reduction in problems with diesel particulate filters (DPFs).  This is because additional soot is created when engines are not running sufficiently hot to optimise combustion. This soot collects in the DPF and the exhaust temperature is often not high enough to burn it off. As the eFan helps keep the engine running at its best temperature, less soot is created.
In more extreme cases of overcooling, it can be that overcooled coolant is released into the engine by the thermostat creating thermal shock which damages the power unit. Only running the fan when it is needed makes overcooling less likely and reduces instances of thermal shock.
Elucidating on the benefits of the eFan, typically, a bus radiator is designed to last a couple of years at most but the eFan is designed to last at least ten years and was essentially a fit and forget type system. A robust technology called bar and plate was used because, while the traditional tube and fin construction method was OK on trucks, it was less durable in bus applications. The eFan is designed to be robust for bus applications, which was hard. Although the eFan is more durable it is not heavier. The complete pack weighs 60-70Kg which is comparable to a conventional hydraulic pack. ‘We don’t have a heavy hydraulic fan and supporting framework,’ said Chris, adding, ‘because of this there is less vibration and less noise.’
Noise is increasingly important and here there are advantages to the eFan in two more respects. Firstly, there is a kerbside quiet feature that has been developed whereby at below 5kmh, the noise output is reduced through an algorithm that prevents overcooling. Secondly, and of local benefit to operators with residential neighbours, is the low start up noise characteristic that it gives a bus because the eFan does not activate as soon as it is turned on, only when the engine reaches a temperature at which it needs cooling. It is also quieter because it runs for less of the time.
An advantage that becomes increasingly important as space becomes ever more at a premium within the bus envelope, is the eFan’s packaging attributes. ‘We can split the charge air from the water and have the relevant components in different locations, which is far more difficult to do with a belt or hydraulic driven system. Also, with one big fan you have to have a big square heat exchanger but with our smaller multiple eFans you can have virtually any shape of heat exchanger.’

Micro Hybrid technology captures the energy generated from a bus’s braking system, and redistributes this energy to power pneumatics, hydraulic and electrical systems which would otherwise require power from the engine.
The result is a reduction in fuel consumption of up to 10%, leading to substantial savings over a bus’s typical 15-year operational service life.

the Micro Hybrid equipment – which charges the batteries during braking to power auxiliaries – deliver a significant fuel saving, it also entitles the operator to enhanced BSOG payments without the extra costs associated with a full hybrid’s complexity and batteries.

StreetLite Micro Hybrid range has achieved Low Carbon Emission Bus Certification. The StreetLite Micro Hybrid is a very low cost hybrid system that allows the bus to recuperate lost braking energy to power the vehicle electrics and the vehicle compressed air system for free. This improves fuel efficiency by approximately 10% on a typical city bus drive cycle.

The StreetLite Micro Hybrid uses the same engine, transmission and rear axle as the conventional StreetLite, but re-jigs the auxiliary systems to give the vehicle smart control of energy generation and usage on the vehicle.
A standard bus driveline has three important extra bits powered by the engine:
1. Air compressor (for brakes) which runs when the air tank pressure is below a given set point
2. Alternator (to charge battery and power lights etc.) which runs continually with a load proportional to the electrical load on the bus
3. Hydraulic pump for cooling fan (to stop the bus melting) which runs continually with a load proportional to engine speed.

Now in the Micro Hybrid, when the driver presses the brake pedal, some of the waste energy is stored in compressed air tanks and the compressor only runs when really, really needed (which is hardly ever on a busy stop-go city route - lots of brake presses.

Likewise with the alternator, but here the spare energy is stored in the batteries. Again the alternator is hardly ever used on a busy city service. The hydraulic pump becomes an electric pump, again running only when needed.

In this way, the load on the engine is significantly reduced, and the auxiliary systems are powered by waste energy that would otherwise be lost. This has the additional benefit of reducing the load on the retarder and brakes, which will also reduce the load on the cooling pack and extend the life of the friction brakes. The overall efficiency gain when Micro Hybrid is added to a conventional StreetLite is around 9.2% and this additional fuel saving is enough to place the vehicle comfortably below the threshold for Low Carbon Emission Bus Certification.

Wrightbus’ “Micro Hybrid” recovers braking energy, but rather than use it to directly benefit propulsion as in full hybrid systems, this energy is stored in storage systems already on board and is used to power pneumatics, hydraulics and electrical items. These components would otherwise require power from the engine and, by using the energy harvested from the braking system, reduces overall fuel consumption by around 10%.

(05 Aug 2015, 7:25 pm)G-CPTN wrote An interesting read - thanks.

(05 Aug 2015, 7:48 pm)Malarkey wrote should test something like that out up here on the Sunderland Connect 700/701 for example when it comes to the time of replacing the Hybrid Solo SRs.

(05 Aug 2015, 8:00 pm)G-CPTN wrote Bring back trolleybuses . . .

(05 Aug 2015, 8:53 pm)Malarkey wrote BYD agree 19m Battery Bus Tie Up with ADL.
http://www.route-one.net/technology/chinese-in-19m-byd-battery-bus-tie-up-with-adl/

(09 Sep 2015, 12:59 pm)Michael wrote Not really new but Mercedes-Benz have announced  they are doing a gas version of the citaro...

http://media.daimler.com/dcmedia/0-921-911857-1-1807800-1-0-0-0-0-0-0-0-0-1-0-0-0-0-0.html