Knorr - Bremse focuses on the future

But India is the undisputed leader in fatality risk per vehicle, with a figure of 1 in 770 compared to 1 in 1,300 for China. To address this the government, in particular the Department of Road Transport, has in addition to asserting the importance of improving road safety from the infrastructure perspective, also been making noises about wanting vehicle safety standards to be upgraded to near-European levels.

Autocar Pro News DeskBy Autocar Pro News Desk calendar 06 Jan 2009 Views icon13721 Views Share - Share to Facebook Share to Twitter Share to LinkedIn Share to Whatsapp
Knorr - Bremse focuses on the future
Accounting for over 80 percent of passenger traffic and over 60 percent of freight traffic, road transport has emerged as the dominant mode of transportation in India with a share of 4.5 percent of GDP, far ahead of the Railways, which accounted for a mere 1 percent in 2004–5 according to data released by the Central Statistical Organisation.

Consequently, it also accounts for the vast majority of transport-related deaths and injuries. Although the total number of road accidents in India involving injuries is significantly lower than in the US, Europe, and Japan, and comparable to the figure in China, these two neighbours vie for the dubious distinction as the countries with the highest number of fatalities.

But India is the undisputed leader in fatality risk per vehicle, with a figure of 1 in 770 compared to 1 in 1,300 for China. To address this the government, in particular the Department of Road Transport, has in addition to asserting the importance of improving road safety from the infrastructure perspective, also been making noises about wanting vehicle safety standards to be upgraded to near-European levels.

The cost implications of any such initiative would appear to be an insurmountable hurdle, especially for commercial vehicle manufacturers in a market where the sole objects are least cost of acquisition and quickest return on investment. To add to that, the downturn in the industry now will put paid to any hope of being able to achieve the desired goal through legislation.

“The government can play a role in the introduction of the latest-generation vehicle safety products through legislation, but cost will remain an inhibitor. The transporter will only be able to buy the vehicle if the operating economics work for him in terms of the number of turnarounds — and that is directly linked to the speed of infrastructure development, the speeds at which these trucks will run on the highways,” says Venkat Potturu, CEO of Knorr-Bremse Systems for Commercial Vehicles (KBSCV).

And secondly, though there has been no shortage of right legislation, what has been missing is the political will to follow through with strict enforcement. Rather, what we see today is the politically motivated relaxation over the last several months of the ban on overloading, which has depressed sales of trucks — and consequently demand for even the most basic versions of ABS from dominant supplier WABCO-TVS and its up-and-coming rival.

Starting in 2007 KBSCV, the German air-brake giant’s 74:26 joint venture with the TACO group, was supplying Tata Motors up to 2,000 ABS kits a month; last month the demand for this standard version was nil.

Rock bottom?

Potturu admits that things couldn’t get worse. Sales of midweight and heavy trucks were down 48 percent in October and 60 percent in November (compared to the same months in 2007), as against growth of 20 percent over the year the industry had projected.

“The heavier vehicles were first hit, as they always are in a recession. Now sales of the lighter vehicles are also dropping. This month Tata Motors plans to build fewer than 4,000 vehicles, instead of the 12,000 they had planned earlier. Only in March they produced 18,000 vehicles. And Ashok Leyland is going to make only 1,000, whereas they had planned to do 9,000,” he says.

The restricted availability of bank finance has certainly been an issue, but now there is a more fundamental one: transporters are putting off or cancelling truck purchases because a steep drop in the demand for transport, he points out.

The ban on export of iron ore and the sudden evaporation of liquidity in construction has had an immediate impact because trucks are used to move ores and construction materials like steel and cement. What demand remains is mainly for movement of cars and consumer goods, and that too is dropping.

The result is that all new truck projects have been pushed back, which in turn has delayed the introduction of a number of hi-spec brake system products KBSCV had geared up to supply for Tata’s World Truck. Notably, these include its ABS6 Premium upgradable with ESP, an integrated air processing unit (APU), and integrated pedal unit with foot brake valve and clutch servo.

And even when production does begin, the volumes may not be as big as earlier envisaged. In any case the conditions for introduction of this vehicle are anything but propitious. Sales of the current generation of heavy vehicles have fallen the most, and the fact that the World Truck is heavier than those certainly isn’t going to help. “Add to that the credit crunch, and I don’t think the numbers will pick up at the rate we desire,” Potturu says.

However, KBSCV has certain fundamental advantages with respect to the competition that will only strengthen its position when the market does pick up. For one, it is the only supplier in India capable of delivering all the components of an air braking system — compressors, air treatment, valves, actuators, foundation brakes, and electronics.

Vehicle manufacturers in India prefer to work with the brake system supplier for the entire system, unlike in Europe, where the OEMs put the system together themselves from components bought from suppliers who can offer the lowest price on each. KBSCV can provide an end-to-end solution, whereas OEMs today have to buy the pneumatic system, slack adjuster, and foundation brake from three different sources.

Two, its German-engineered products are manufactured from high-grade materials and are far more robust than the highly value-engineered offerings of its larger competitor. They have not needed to be modified in any way for this market; the only change compared to the European base product perhaps being the application-related repositioning of ports.

This reflects in their superior performance in the field, borne out by a study its operators did in the last few months. “Since we didn’t have a service support network our products would have to speak for themselves. We found out they are actually performing far better than the competition, which has about 220 service stations across the country taking care of their performance,” Potturu points out.

Another finding of note was that whereas transporters routinely needed to replace the O-rings and seals in the foot brake valves supplied by the said competitor, Knorr’s valves performed reliably without service. This kind of quality does not come cheap. Knorr components are more expensive, but come with a 200,000 km warranty, double that originally offered by the competition.

Then there is the brake system KBSCV developed for the World Truck, which is a generation ahead of what it supplies for the existing vehicles in terms of features and response characteristics of the components, and those in turn were more advanced than the products available in the market at the time they were introduced.

An interesting feature of Knorr products are their modular construction. For example its ZB44 APU for the World Truck integrates field-proven components – LA8 air dryer with integrated heater and unloader valve, AE44 four-circuit protection valve with exhaust functionality of the AE46 valve, and an oil separator – into one compact unit.

Designed to allow regeneration of the molecular sieve by a reverse flow of compressed air from the system reservoir itself instead of a dedicated purge tank, it offers significant packaging advantages to the DDU (drying and distribution unit) supplied by the competition for the last two years. The DDU is bulkier because it includes the volume of the purge tank, and consequently more difficult to applicate, because a larger system would require a larger purge tank, creating packaging difficulties. Foundation brake

KBSCV has the advantage of full access to its parent company’s extensive library of components, from which it just needs to pick the right ones for the intended application. However, the job of engineering the entire system involves much more than that. The components are sized and the entire system configured using Knorr proprietary software, which can also be used to simulate the performance of the system for the intended axle loads and speeds.

Last year it began production of the Knorr ASA-6 self-setting automatic slack adjuster, which it supplies to Tata Motors. A 325mm S-cam brake, originally designed by Bendix Spicer Foundation Brake (a joint venture between Bendix and Dana), the lead drum brake design centre within the Knorr-Bremse global organisation, is fully tested and ready for manufacture, and work has begun on a 410mm version.

In fact the plan was to bring in Bendix’s unique single-anchor-pin design because of its better wear characteristics and absence of squeal, but had to drop that because of Tata’s preference for the conventional twin-anchor-pin design. But even with this design, the OEM’s exceptionally challenging cost target has been impossible to meet so far because of the high metal prices. “We have the machinery and the tooling, we’ve also developed the suppliers. All we are waiting for is the commodity prices to come to a controllable level to start manufacturing,” Potturu says.

Apart from complete systems for Tata’s 1613 two-axle and 2516 and 3118 multiaxle models, it supplies ABS ECUs and valves for the 4018 and 4923 tractors. It also supplies the complete pneumatic actuation system for TACO Hendrickson’s Pararev lift axle on the 3118, consisting of the load sensing and axle lift control valve, plus the actuators for the unique camber-reversing mechanism.

“We supply these components directly to Tata, which fits them onto the basic hardware supplied by TACO Hendrickson. In fact the valves and actuators were specially designed for this application by Knorr-Bremse UK working together with Hendrickson Europe. Now that we are here, we can work with TACO Hendrickson locally and develop products for the future,” he says.

In 2008 KBSCV was awarded exclusive supply contracts by Ashok Leyland for the latter’s 1613 tipper and 816-series LCV, and a bus programme is expected to be announced shortly. It is also working on brake systems and exhaust brake cylinders for Mahindra Navistar, this correspondent learns. Actuated by a switch on the driver’s console, the exhaust brake engages before the service brake when the foot pedal is depressed for smoother, more effective braking.

For LCVs above 7.5 tonnes Potturu sees opportunities in the future, in particular for Tata Motors’ Y1. In addition, Autocar Professional learns that KBSCV has already started work on brake systems for Daimler Hero’s midweight and heavy trucks currently under development by Ricardo and Magna Steyr respectively.

The trailer industry has also attracted its attention; it presently supplies brake chambers and ABS (for tank-trailers) to DLT, has started discussions with PL Haulwel, and Potturu admits the RSB group’s trailer project expected to come up at Khopoli is another interesting prospect.

Knorr brakes come standard-fitted from Germany on the ZF deep-drop front axles fitted on Tata’s Starbus low-entry models, and its electronic levelling control (ELC) valves handle lift and kneeling functions on the Starbuses supplied to BEST in Mumbai. Last year the company applicated a disc brake for the front axle of the iBus that Ashok Leyland demonstrated at Auto Expo 2008.

Manufacturing these in India is not an economical proposition yet because the volumes are still small, Potturu points out: “The number of buses on which the disc brake sits is not more than 2,000 a year. But we know that in the long run the Indian regulations are moving towards ECE R13, and surely all these latest technology brake systems will be used in India too.”

In any case disc brakes, he believes, will only really catch on in the next generation of buses. “The current generation use discs on the front axle and drums at the rear. This is definitely not advisable because it increases the load on the front axle and brake pads wear faster. The two have to be matched, and it is better to use disc brakes at all four ends.”

Knorr’s ABS Premium system that will go onto the World Truck, offers an array of functions such as ASR (traction control), electronic brake force distribution, brake diagnostics, and drag torque control, and lends itself to upgradation with driving stability functions similar to ESP (Electronic Stability Program), which intervenes to restore directional stability when there is a difference between the driver’s steering input and the vehicle’s actual movement.

KBSCV has completed development of two new water-cooled clutch compressors for five- and six-litre engines for introduction by end-2009 — a 225cc model for higher-end LCVs and MCVs, and a 360cc version for buses, which have a higher air requirement for the air suspension and auxiliaries like door opening mechanisms. Both promise superior air delivery by design, and higher fuel savings than competing designs because of a the ability to disengage the compressor from the engine when the required pressure has built up in the system.

Next in the pipeline are “aggregates” combining actuator, slack adjuster, and S-cam brake, for instance, or a driver control module, a higher-end version of the pedal unit integrated with the steering column.

The introduction of the electronic braking system EBS which Knorr pioneered is a more distant prospect, Potturu says. “The OEMs are looking at EBS from a long-term perspective. This present downturn may delay things, but surely when the roads are improving, everybody wants to make futuristic vehicles. And when you have futuristic vehicles, you will have electronic braking systems.”

What’s of more immediate interest is the viscous torsional vibration dampers from Knorr subsidiary Hasse & Wrede, the largest manufacturer of this device worldwide. These dampers, which use a silicone fluid, prevent crankshaft damage from engine vibrations at high speeds and are more suitable for engines rated at 200 hp and above than the solid rubber variety currently fitted in the present generation of six-litre engines.

The flywheel is mounted on the damper, which is assembled onto the end the crankshaft. “Our torsional vibration dampers allow the use of lighter crankshaft and counterweight designs for higher power requirements and thus reduce the weight of the engine. This is a crucial advantage for OEMs engaged in new engine programmes for BS4 and BS5,” Potturu says.

Asked about the export prospects for the products KBSCV makes, Potturu cites “inter-company” opportunities within the group for product lines for which the global demand is limited because of a growing shift to electronic braking systems and disc brakes. These will include regular pneumatic valves, slack adjusters, and drum brakes for the emerging markets.

“Since Knorr-Bremse has plants all over the world, we try and make products locally to meet local customer requirements. Bendix in the US, and the Knorr plants in Brazil, China, and India, produce all the lines. But in Europe we have a centre of competence (CoC) for each product that designs, develops, and manufactures that product line for the whole of Europe,” he elaborates.

KBSCV itself is evolving into a CoC of sorts for slack adjusters, of which it is already developing a few models for an East European customer. Potturu says there is also scope to work with Bendix Spicer on drum brakes for world markets. Manufacturing will of course be initially for the domestic market and then extended to other markets.

“We are just a small company, but we are developing competences for the future. We are building the required infrastructure and the required people capabilities, and right now we are working with the existing CoCs for the future,” he says modestly.

Having more than doubled its revenues to Rs 100 crore in 2007–8, Potturu is certain KBSCV will achieve its target market share of 50 percent by 2012 regardless of the downturn. In normal conditions it would have been reasonable to expect a spike in sales in 2009 as a result of pre-buying ahead of the introduction of the BS3 emission norm countrywide in 2010, but now there’s no telling whether that will happen.

“The numbers are down, but I’m sure things will pick up after 2010. It’s only a question of going through this difficult year of 2009,” he says.


In addition to braking and safety systems, Knorr-Bremse has developed pneumatic systems aimed at greater energy efficiency and reducing emissions. At the recent IAA Commercial Vehicles in Hanover the company showcased three innovations that have the potential to enhance the competitiveness of manufacturers and fleet operators and at the same time reduce costs.

The first is its EAC electronic air control system, which integrates the air dryer, pressure regulator, and multi-circuit protection valve into a single unit and combines tried-and-tested pneumatic components with intelligent electronics. EAC2, the latest generation, has been designed as a platform module capable of integrating further functions including reducing compressor fuel consumption.

An optimised control system reduces the air requirement for regeneration of the air dryer’s molecular sieve and the overrun control uses excess energy to feed the pneumatic system. On uphill gradients or during overtaking, EAC2 switches the compressor to neutral, reducing engine load during acceleration.

Unlike conventional systems that operate independently of the drive situation, EAC2 saves fuel by intelligent regulation. Measurements on various road circuits indicate potential savings of several hundred litres per year, depending on the journey profile.

Another function that can be integrated into EAC2 is compressor clutch control. The clutch developed by Knorr-Bremse enables the compressor to disconnect from the engine when the braking system has reached its operating pressure, whereas conventional applications continue to operate the compressor even without back-pressure.

Direct control of the clutch either via EAC2 or using a supplementary software package can optimise energy savings and prolong the service life of the compressor. The annual savings that can be achieved run to some 900 litres per truck (on average European motorway runs). And lower fuel consumption means a truck fitted with such a compressor with clutch can reduce CO2 emissions by 2.5 tonnes per year.

The third technology solves the problem of diesel turbo lag. When a driver presses the accelerator, the Pneumatic Booster System (PBS) injects precise quantities of compressed air into the engine intake duct. The engine reaches maximum torque within half a second and effectively avoids the problem of turbo lag during acceleration.

An engine equipped with PBS achieves greater torque immediately after an upward gear change, allowing the driver to change up at lower rpms, thus maintaining the optimum engine speed for fuel economy and delivering potential fuel savings of up to 2 percent.

These technologies might appear futuristic for the Indian market, but Potturu does nevertheless see scope to partner with domestic truck OEMs on their long-term projects, for both EAC and PBS, and mechatronic transmission automation systems as well.

“We have already made presentations on these technologies, and also demonstrated them to the OEMs when they visited the IAA. All of them want go global and export their vehicles. Not only that, but they also want to introduce products of global standards in India. They are definitely interested in taking their vehicles to the next levels of technology. Now it’s only a question of how quickly they want to integrate these systems into their products,” he says.


Knorr EBS: How it works Knorr’s EBS electronic braking system brings together a wide range of electronic systems aimed at improving vehicle safety and reliability. It integrates the traditional braking system with functions such as ABS, traction control, and (in EBS5) retarder blending to form a single, integrated safety system.

The brake function is triggered by a foot brake “module”, essentially a foot brake valve with a travel sensor that communicates with the engine-ECU-interfacing central ECU. The module is designed to fall back on conventional pneumatic control if the electronics fail.

The central ECU controls the electronics in electropneumatic modules (EPMs) on the front and rear axles via a CAN data link. The EPMs are assemblies of solenoid valves, relay valves, and pressure control modulators with wheel speed and brake wear sensors and local electronics.

The electronics within each EPM trigger their solenoid valves, implement the ABS function, and evaluate the signals from the wheel speed sensors and brake wear sensors. The pressure control modules feed air to the brake actuators and control the pressure in accordance with the control input. This results in braking pressure building up not only faster, but also simultaneously in all brake actuators.

The response to the driver input is instantaneous, and the direct application of brake pressure by the EPMs to the actuators also helps reduce the stopping distance. At the same time, the excellent control sensitivity serves to increase braking comfort.

EBS ensures that an equal demand is placed on each brake; when the brakes are released, all the brake actuators are exhausted immediately and quickly. The brake wear control function ensures that the brake pad/disc wear is uniform throughout their service life. This means an increase in the useful life of the brakes of up to 20 percent.

EBS 5 includes the ESP electronic stability program, which actively intervenes in the vehicle’s braking and engine management system and helps the driver maintain control in critical situations. If there is a risk of rollover or jackknifing, ESP selectively applies the brakes on individual wheels and reduces engine torque, defusing potentially dangerous situations and in many cases preventing accidents. The entire process is transparent to the driver.

It also includes the Active Brake Assist function that monitors the driver’s use of the brake pedal, automatically sensing an attempt to stop the truck as a result of panic. The system then instantaneously generates very high braking power, even when the driver is only pressing the brake pedal lightly. Used together with ABS, Active Brake Assist results in faster and safer braking in emergencies.
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