Into the heart of truck hydraulics

In 2004 Interpump Hydraulics, the largest manufacturer of power takeoffs in the world, decided to set up a subsidiary in India to upgrade the decades-old technology of truck hydraulics that it saw was clearly inadequate to meet the performance and efficiency demands of a growing number of infrastructure applications that were then emerging.

A power takeoff (PTO) is a device that extracts power from the engine or transmission by means of a geared mechanism and delivers it to an auxiliary device for use in work functions such as actuating a tipping or compacting cylinder, driving the drum of a transit mixer or roadsweeper, or powering a crane or a high-pressure pump for cleaning sewers.

The PTOs then available were all manually operated and side-mounted on the transmission. The problem was, if the pump attached to the PTO seized, the entire force would act to twist the PTO off the gearbox, causing the gearbox casing to fail. In earlier years these had been made of cast iron, but seven years ago, with the Euro regulations and the need to make vehicles lighter, the OEMs in Europe all moved to aluminium housings.

Since aluminium was less capable of withstanding the stresses generated by side-mounted PTOs, suppliers like Eaton and ZF started closing the side opening, opting instead to install rear-mounted PTOs (RPTOs). The advantage here is that even if the pump jams, the reaction is contained within the PTO mechanism and there is no separating force that acts to cause any part in the gearbox or casing to fail.

But the market in India was still dominated by side-mounted PTOs — mechanically operated, with linkages running all over the place. “The first technological improvement we brought in was a rear-mounted PTO for Ashok Leyland and we demonstrated its advantage — half the weight of side-mounted PTOs, and half the cost,” says P Ramesh Joshua, managing director of Interpump Hydraulics India.

“The second was, we replaced the rod or cable linkage with pneumatic operation. With the advent of tiltable cabs, the mechanical linkage had become a big disadvantage as it had to be disconnected entirely to be able to lift the cab.

We came out with a pneumatic hose that plugs into the PTO with a quick connector — all you do is pull it out and lift the cab, and then push it back in after the cab is lowered.”

The PTO drives a hydraulic pump, which in India has traditionally been of the axial-piston plunger type, for tipping applications. These pumps are ideal for continuous operation, run trouble-free for life, and – in Europe – are used for high-pressure applications above 250 bar. But they are noisy and “rpm-limited” to around 1,600 rpm, and – in India – far too heavy and bulky for the intended application (tipping), given that the pressure actually required is no higher than 170 bar.

“We were the first to introduce gear pumps, which are half the weight, and again, half the cost, of the plunger pumps. They are also very flexible because they are revolution-dependent — the faster they rotate, the higher the flow they generate,” says Joshua.

Ashok Leyland was IPH India’s first customer for pneumatically operated RPTOs and gear pumps, assembled together and tested as a unit, which it has fitted onto its ZF S 5-36, ZF S 6-36, and ZF 9S 109 gearboxes since 2005. Initial supplies were from Italy, and since October 2006 these have come from IPH India.

In fact, till the recent downturn, Ashok Leyland bought the entire requirement for its annual tipper production of 17,000–18,000 from IPH India, including 300 a month for the ZF 8S 109 gearbox on its heavy-duty mining tippers, and there are currently 50,000 PTO/pump units in operation all over India.

With the side-mounted PTOs there would be a propeller shaft to the pump, which was mounted somewhere in the chassis because of the bulk of these piston pumps and other reasons. Now the PTO and gear pump, which together weigh less than 20 kg, are simply “unit-mounted”.

“Because the weight of the combination is so small, the whole weight is now approved by the gearbox manufacturer. Earlier, the side-mounted PTO and pump put together would weigh 30 or more kg — we were able to reduce that by 10kg. And the combination is also more cost-effective,” he points out.

Big opportunity in waste

The company sees big business in garbage compactors, for which it offers a clutch PTO that can be engaged only for the few seconds that the compaction actually happens.

Most existing trucks have the same PTO on them as on tippers, which means both PTO and pump are kept running continuously. This is because the main PTO is operated from within the cabin, whereas the compactor is operated from the rear of the truck.

This is a big disadvantage if the driver, as in Europe, has to do both jobs. To address both the high incidence of pump failure arising from continuous operation, and the inconvenience to the operator, IPH India has developed a ‘hot-shift’ add-on device for its existing PTOs. This is a pneumatically actuated clutch pack to be retrofitted on the output end that engages the PTO – and simultaneously effects the compaction – at the press of a button and disengages it immediately when the switch is released. So the PTO works for only 15 or 20 seconds, or only as long as it takes to operate the compactor.

“We are a major supplier of hot-shift PTOs to all the major Italian solid waste management companies, including Farid and Rossi. Lots of people are coming into garbage compacting in India now. Today the biggest manufacturer is Antony Motors in Mumbai. Others in the business include Kam-Avida, and Gat-Ray Envirotech Systems, both from Pune. Hyva has introduced a compactor in collaboration with Dennis Eagle.

Vectra Motors (formerly Tatra Vectra), in collaboration with Czech company Orbit, has already built its first prototype on a Tata 407, and wants to use our PTO plus hotshift,” Joshua says.

For sewer cleaning applications IPH India sells 200 units a year of PZB’s advanced split-shaft PTOs, which it imports from Italy for customers that include Kam-Avida, Gat-Ray, TPS in Faridabad, and ITWT in Mumbai. “Any and every municipal tender in India specifies PZB PTOs,” he points out.

This product is similar in construction to a transfer case; one propeller runs from the gearbox to the PTO and another from the PTO to the axle. When the truck is stationary, it allows the axle drive to be disconnected so that the full engine torque is available for the work function.

“Earlier on everyone would use a very crudely fabricated transfer case onto which they would fit a PTO and pump. But this was grossly inadequate for sewer cleaning, which requires almost 150 hp to drive the high-pressure jetting pump,” he explains, adding that Pratissoli-brand pumps from Interpump Group’s industrial division are also quite popular for this application, though imported directly, not through IPH.

Split-shaft PTOs The split-shaft PTO comes with up to four drive outputs, all of which are needed only perhaps for roadsweeping. Even so, it is not really suitable for a roadsweeper, which functions effectively only when the vehicle moves. But it has to move at 2km/h, whereas the engine has to operate at full throttle to generate maximum suction. Even in first gear, the truck will move at not less than 10 km/h at full throttle.

To reduce the speed to 2km/h, roadsweepers made in India have a very peculiar arrangement — they use two gearboxes, one behind the other, to multiply the first gear reduction. And for the suction they use a separate donkey engine. This is a very heavy, inefficient way of doing things.

Earlier this year IPH introduced an advanced version of the split-shaft PTO in Europe that can drive the rear axle hydrostatically via a pump fitted to one of the PTO outputs. The regular shaft drive remains; the vehicle is only driven in hydrostatic mode when the sweeper/suction mechanism is activated. “We are working with both Ashok Leyland and Roots India on introducing this product,” Joshua reveals.

Although Tata Motors is not a direct customer for its PTOs and pumps for heavy trucks yet, IPH India does supply a few PTOs, pumps, and cab control (pneumatic) valves for high-end applications to TAL Manufacturing Solutions, the subsidiary to which Tata hived off its own 40-year-old pump, valve, and underbody tipping kits business recently.

It is also working on a pneumatically operated PTO for the next generation of Tata’s LPT 909 intermediate-weight truck, designated Y1. But even more exciting is the PTO/pump unit that Hydrocar (see factfile on page 81) on has developed exclusively for the Ace minitruck, for which Joshua expects volumes of about 100 a month. “This is the smallest PTO we have ever made anywhere in the world. My Italian colleagues call it a toy,” he says.

The joint design project with Tata was started in February 2007 and completed in Italy. IPH India built the prototype, which was then validated back in Italy on an Ace gearbox supplied by Tata. The production phase is just beginning, Joshua says, and Tata has agreed to release gearboxes with a PTO opening from January 2009.

The company was expecting to work on a version for the one-tonne Ace as well, but Joshua says there’s been no movement by Tata on that front. In the meantime he has bought a few gearbox casings, got them machined himself to drawings supplied by Tata, and sold them with PTO mounted to Ace dealer Prerana Motors in Bangalore.

“This will allow the Ace to be fitted with small cranes or sewer cleaners, as used by the Pune Municipal Corporation. Right now these use a hydraulic powerpack, or a separate engine, or connect the pump via a belt so that it runs continuously while the vehicle is running. Most hydraulic applications you can imagine on the Ace will use our PTO,” he says.

The company has also completed a vacuum-operated design for Mahindra Navistar’s Loadking LCV, which is fitted with a vacuum brake system. IPH is the sole supplier of PTOs to Eaton worldwide, and IPH India will likewise supply all the PTOs that go onto gearboxes shipped from Eaton’s truck component operations in Ranjangaon near Pune. In fact it has already received an order for 200 PTOs to be fitted on Eaton FS 10309 gearboxes to be supplied to AMW, and Joshua reveals he is in talks with Eaton for exports to one of the latter’s European plants as well.

Products whose time has come

The company manufactures 2,000 PTOs a month at its Hosur plant, and sells around 1,700 PZB pumps, all presently imported from Italy. IPH recently inaugurated a joint venture in China, and Joshua says the pumps will likely be sourced from there next year after PPAPs with Ashok Leyland and its other customers.

It plans to manufacture the hydrostatic transmissions in India, at least partially. “We will mainly assemble, test, and sell. It may be uneconomical to make 100 aluminium housings a year, as these are of a complicated design, and we have the choice of buying the housings from Italy.

However, we may make the gears here, and the mounting brackets and their rubber padding, for which the requirements are very stringent,” he says.

The next immediate addition to its production portfolio will be engine-mounted PTOs for part-power, continuous applications like transit mixers, where the drum must rotate all the time, whether the vehicle is stationary or in motion, or for air-conditioners for buses. It is already engaged in programmes for Ashok Leyland, Tata Motors, and Eicher, and is beginning to work for Cummins on its engine programmes for these OEM customers.

Today most manufacturers of buses and chassis use toothed belts to run the AC compressor. The problem is, the continuous, non-synchronous vibrations of the engine and compressor lower the life of the belt.

An alternative is to drive the compressor directly off the PTO via a propeller shaft, or if there isn’t enough space, to drive the compressor hydrostatically off a pump on the PTO. This arrangement could also be used to power a fan drive or any other auxiliary, he explains.

The company presently imports the pneumatic cab control and tipping valves it supplies to TAL and (together with its PTOs) to Wipro Infrastructure Engineering for the latter’s tipper wet kits. Like some of the tipper valves available on the market (from UT Ltd, for example), the IPH products protect the pump, i.e. they have a relief mechanism on the pump side, rather than the cylinder, because that is where IPH is coming from. (Hyva, on the other hand, supplies valves that protect the cylinder.)

Now IPH has designed and patented a valve that will protect both pump and cylinder in the event of a sudden increase in loading on either side. Currently under validation in Italy, this valve will be manufactured in India in the next two months and supersede the existing products, both here and worldwide.

“The truck manufacturers are fed up with either the cylinder failing – the seals in the cylinder blowing – or the pump blowing. Today they really don’t have a choice. So they are all looking for a valve like this. And if it is indigenously manufactured it will definitely be very cost-effective,” Joshua points out.

This valve will be introduced as part of a complete wet kit – consisting of PTO, pump, cab control valve, hydraulic tank, hoses, and cylinder from HS Penta of Faenza, Italy – for tippers that the company hopes to supply to the truck OEMs, and large bodybuilders like TSI, ACCL, and PL Haulwel, beginning February 2009. This will pit it directly against Hyva India (a former customer for its PTOs and pumps), Wipro, and UT Ltd.

IPH India has supplied one prototype wet kit to Ashok Leyland, and is trying to facilitate a collaboration between HS Penta and Automotive Coaches & Components (ACCL), a Leyland subsidiary, for local manufacture of cylinders.

HS Penta, a company IPH is acquiring the owning family’s holding of 30 percent in, specialises in underbody and front-mount cylinders for tippers, and wet kits. IPH has also acquired two other Italian cylinder manufacturers, one supplying to the earthmoving equipment industry and the other 100 percent specialised in long garbage-compactor cylinders.

Optimistic outlook

As for his outlook on the recession and the prospects for the industry in 2009, Joshua expresses optimism that the market will bounce back – even if not to the level it was at in September, to maybe 80 percent of that – in the next six months.

“Our product goes into the infrastructure business, and the finance minister has told us the government is not stopping any infrastructure projects but only postponing them. Right now because of the automotive industry shutdown the steel companies are shut down, the mines have shut down, and there’s a surplus,” he says.

But even when it bounces back the country will still have surplus capacity for tippers, he feels. In that case the competition between the truck manufacturers is going to be fierce. “The good thing for us is, we can supply to any truck manufacturer, regardless of which gearboxes they use — Tata, Eaton, or ZF.”

Besides, IPH India plans to concentrate on solid waste management and roadsweepers with its hot-shift, split-shaft PTO, and hydrostatic transmissions. “These segments are going to grow by leaps and bounds in India, and that is where we would like to be,” he says.

Going forward, Joshua sees tipping gear and PTOs accounting for the bulk of IPH India’s business, which stood at Rs 24 crore in 2007–8. “We have the products ready. Now we are working with the industry. In six months volumes should pick up to reasonable levels. And with the introduction of our high-end products, which are more expensive, our turnover will definitely grow.”