His plan was to create a vehicle which really does put the cart before the horse.
And once he’d got the bit between his teeth, wild stallions couldn’t tear him away from his favourite hobby.
The result of his labours is a one horsepower, space age all-weather buggy powered by, ugh, a horse.
Unlike traditional horse-drawn vehicles, the horse rides inside, behind the driver, protected by an all-weather canopy.
And thanks to a lightweight polycarbonate frame and complex gearing, it can reach speeds of up to 80km/h – although its cruising speed is a more sedate 20km/h.
"My friends and relatives thought of me as a somewhat eccentric half-mad inventor attempting the impossible," said Mirhejazi, an Iranian engineer who has brought his invention to Dubai. Nevertheless, one friend was prepared to rustle up enough cash to put the project under starter’s orders.
"It took me 26 months to build the vehicle in my workshop in Tehran. I got it patented by a special department in Iran after professors at universities there attested that it was a scientific invention."
The horse walks on a fibreglass treadmill, generating enough power to move the 300kg Naturmobil along on six motorcycle wheels.
Mirhejazi says it produces enough surplus energy to charge a small battery which powers the buggy’s lights, electrical system, and can even take over from the horse when Neddy needs a rest.
When the horse’s body temperature gets too hot for comfort, a sensor attached to its side transmits its temperature reading to a controller which automatically turns off the treadmill and switches the vehicle to run on battery power.
Neddy can then rest for 20 minutes before the back-up power runs down.
Mirhejazi, who runs a business specialising in agricultural machinery, said he came up with the idea after pondering how to utilise horses in new, cruelty-free ways.
"I first tested the vehicle in January 2006. It was around 2am and the deserted streets of Tehran in Iran were perfect for the experiment," he said.
"My brother Saleh was behind the steering wheel."
Mirhejazi has already exhibited the Naturmobil in Geneva, and plans to take it to the upcoming Invention and New Product Exhibition in the city of Pittsburg in California, USA, this June.
"After the show, I intend to have a live demonstration there with a locally procured horse and hope to attract some sponsors," he said.
He needs sponsors to fund the creation of a second-generation Naturmobil – a four-horse coach intended to carry tourists.
And he hopes the bizarre design of the existing Naturmobil will attract enough attention to help fund the next version.
Mirhejazi also discovered the horse can power two LCD advertising screens mounted on the sides of the Naturmobil
"Bearing in mind the originality and uniqueness of the idea, Naturmobil was designed and built to achieve the maximum level of attention from its audiences," said his marketing manager, F. Minooeifar.
Comfort and safety in mind
Mirhejazi says the Naturmobil was designed with the safety and welfare of the animal in mind. No whipping is involved.
To make the horse move, the driver flicks a switch to make the conveyor belt, where the horse is mounted, move.
The belt is lifted to simulate an uphill condition to prevent friction from harming the horse.
The gearbox is designed to ease the pressure on the horse.
The horse need not exert its full power to achieve a faster speed.
Shock absorbers are placed under the conveyor belt to lessen the impact on the horse’s joints.
A digital display unit allows the driver to monitor the horse.
Two sets of sensors are attached to the horse to monitor its heart rate and body temperature.
A bower attached on top of the vehicle is designed to protect the horse from cold and heat and can be opened if the horse needs air.
The horse is made to wear special soft leather shoes, tied with laces, to make walking as comfortable as possible.
A waste bin is also provided to collect the horse’s discharges. Another bag is provided for food.
A specialist in agricultural machinery, Abdolhadi Mirhejazi is a graduate of Agriculture
He established the Pajoohesh and Ideh Company to set up greenhouses for olive plantations in Tehran, Iran.
In 1992, he invented a device for improving the efficiency of underground water pumps
In 2004, he developed a crankless one-stroke multi-fuel combustion engine for automobiles
He acquired a patent for the Naturmobil, a horse-powered vehicle, in 2005
Mirhejazi presently lives in Jumeirah in Dubai